I2BC Paris-Saclay
11.9K views | +0 today
 
Scooped by I2BC Paris-Saclay
onto I2BC Paris-Saclay
Scoop.it!

Save the date! - I2BC PhD students' symposium - 16-17th June

Save the date! - I2BC PhD students' symposium - 16-17th June | I2BC Paris-Saclay | Scoop.it

 Today, we announce an exciting event organized on the CNRS campus of Gif-sur-Yvette, by the young scientists of I2BC and for I2BC doctoral students: the I2BC doctoral students' symposium.

Save the date : 16 & 17th June.

Essentially build around the scientific work of I2BC doctoral students, speakers will also be invited to these two days of seminars and posters. Participating in doctoral students' symposium gives you the opportunity to have an overview of the new projects of I2BC groups.

sofia carlos's curator insight, April 10, 2022 8:46 PM
fedinan levi's curator insight, May 25, 2022 7:24 AM

achete de MORPHINE
acheter ultram en ligne
acheter ultram en ligne
acheter du soma en ligne
achete klonopin
achete 4 dmt
achete 5 meo dmt usa
achete adderall en ligne
achete adipex
achete ambien
achete de la cocaine
achete de MORPHINE
acheter ultram en ligne
achete de MORPHINE
acheter ultram en ligne
achete percocet
achete de loxycodone
achete morphine
achete du suboxone
achete du fentanyl
achete dmt
achete de lheroine
achete klonopin
achete 4 aco dmt
achete 5 meo dmt usa
achete adderall en ligne
achete adipex
achete ambien
achete codeine en ligne
acheter de loxycodone
acheter actiskenan
acheter percocet
morphine
acheter ultram en ligne
injection-de morphine
achete de lheroine
achete codeine en ligne
acheter de loxycodone
acheter actiskenan
acheter percocet
morphine
acheter ultram en ligne
acheter ativan en ligne
injection-de morphine
acheter oxycontin
acheter phentermine en ligne
acheter tren a en-ligne
acheter trenbolone enanthate
acheter trenarapid en ligne
acheter de la cocaine
acheter demerol
acheter desoxyn
buy dexedrine online
acheter dilaudid en ligne
acheter du fentanyl
acheter du ritalin
acheter du suboxone
acheter du xanax-vert
acheter norvas 10mg
acheter oramorph
acheter rubifen
acheter subutex
acheter tramadol
acheter vicodin
acheter vyvanse
achete xanax

https://achetmorphine.com/
https://achetmorphine.com/produit/
https://achetmorphine.com/produit/achete-klonopin/
https://achetmorphine.com/produit/acheter-4-aco-dmt/
https://achetmorphine.com/product/acheter-5-meo-dmt-usa/
https://achetmorphine.com/product/acheter-dmt/
https://achetmorphine.com/product/polvo-de-ketamina/
https://achetmorphine.com/product/acheter-flakka-a-pvp/
https://achetmorphine.com/product/acheter-mdma-crystal/
https://achetmorphine.com/product/comprar-etizolam/
https://achetmorphine.com/product/acheter-du-soma-en-ligne/
https://achetmorphine.com/product/acheter-ultram-en-ligne/
https://achetmorphine.com/product/comprar-micro-mushrooms/
https://achetmorphine.com/product/acheter-seconal-sodium/
https://achetmorphine.com/product/comprar-cianuro-de-sodio/
https://achetmorphine.com/product/acheter-psilocybe-cubensis/
https://achetmorphine.com/product/poudre-de-nembutal/
https://achetmorphine.com/product/golden-teacher-crecer-rapidamente/
https://achetmorphine.com/product/acheter-nembutal-liquide/
https://achetmorphine.com/product/acheter-norvas-10mg/
https://achetmorphine.com/product/acheter-des-pilules-de-nembutal/
https://achetmorphine.com/product/acheter-adderall-en-ligne/
https://achetmorphine.com/product/acheter-adipex/
https://achetmorphine.com/product/acheter-ambien/
https://achetmorphine.com/product/acheter-amlodipine-en-ligne/
https://achetmorphine.com/product/acheter-buprenorphine-hcl/
https://achetmorphine.com/product/acheter-de-lheroine/
https://achetmorphine.com/product/acheter-actiskenan/
https://achetmorphine.com/product/acheter-de-loxycodone/
https://achetmorphine.com/product/acheter-oxycodone-mallinckrodt/
https://achetmorphine.com/product/acheter-de-loxycodone-sandoz/
https://achetmorphine.com/product/acheter-de-loxycodone/
https://achetmorphine.com/product/
https://achetmorphine.com/product/acheter-ativan-en-ligne/
https://achetmorphine.com/product/acheter-percocet/
https://achetmorphine.com/product/acheter-tramadol/
https://achetmorphine.com/product/morphine/
https://achetmorphine.com/product/acheter-codeine-en-ligne/
https://achetmorphine.com/product/injection-de-morphine/
https://achetmorphine.com/product/acheter-phentermine-en-ligne/
https://achetmorphine.com/product/acheter-oxycontin/
https://achetmorphine.com/product/acheter-tren-a-en-ligne/
https://achetmorphine.com/product/achetez-trenbolone-enanthate/
https://achetmorphine.com/product/acheter-trenarapid-en-ligne/
https://achetmorphine.com/product/acheter-de-la-cocaine/
https://achetmorphine.com/product/acheter-demerol/
https://achetmorphine.com/product/acheter-desoxyn/
https://achetmorphine.com/product/buy-dexedrine-online/
https://achetmorphine.com/product/acheter-dilaudid-en-ligne/
https://achetmorphine.com/product/acheter-du-fentanyl/
https://achetmorphine.com/product/acheter-du-ritalin/
https://achetmorphine.com/product/acheter-du-suboxone/
https://achetmorphine.com/product/acheter-du-xanax-vert/
https://achetmorphine.com/product/acheter-norvas-10mg/
https://achetmorphine.com/product/acheter-oramorph/
https://achetmorphine.com/product/acheter-rubifen/
https://achetmorphine.com/product/acheter-subutex/
https://achetmorphine.com/product/acheter-vicodin/
https://achetmorphine.com/product/acheter-vicodin/
https://achetmorphine.com/product/achetez-vyvanse/
https://achetmorphine.com/product/acheter-xanax/

https://dolorendo.com/
https://dolorendo.com/product/
https://dolorendo.com/product/comprar-oxicodona-en-linea/
https://dolorendo.com/product/comprar-oxicodon/
https://dolorendo.com/product/comprar-oxynorm-en-linea/
https://dolorendo.com/product/comprar-oxycontin-en-linea/
https://dolorendo.com/product/comprar-percocet-en-linea/
https://dolorendo.com/product/comprar-oramorph-sr/
https://dolorendo.com/productos-comprar-dilaudid/
https://dolorendo.com/product/comprar-vyvanse-en-linea/
https://dolorendo.com/product/comprar-suboxone-en-linea/
https://dolorendo.com/product/comprar-subutex-en-linea/
https://dolorendo.com/product/comprar-pastillas-nembutal/
https://dolorendo.com/productos-comprar-dilaudid/
https://dolorendo.com/product/comprar-acetaminofen-codeina/
https://dolorendo.com/product/comprar-adderall-en-linea/
https://dolorendo.com/product/comprar-desoxyn-en-linea/
https://dolorendo.com/product/comprar-dexedrina/
https://dolorendo.com/product/comprar-dmt-en-linea/
https://dolorendo.com/product/comprar-ketamina/
https://dolorendo.com/product/comprar-klonopin/
https://dolorendo.com/product/comprar-morfina/
https://dolorendo.com/product/comprar-ritalin/
https://dolorendo.com/product/comprar-cristal-mdma/
https://dolorendo.com/product/buy-seconal-sodium/
https://dolorendo.com/product/comprar-4-aco-dmt/
https://dolorendo.com/product/comprar-5-meo-dmt/
https://dolorendo.com/product/comprar-adipex-en-linea/
https://dolorendo.com/product/comprar-alphabol-cr/
https://dolorendo.com/product/comprar-ambien-en-linea/
https://dolorendo.com/product/golden-teacher-crecer-rapidamente/
https://dolorendo.com/product/comprar-buprenorfine-en-linea/
https://dolorendo.com/product/comprar-cianuro-de-sodio/
https://dolorendo.com/product/comprar-cocaina/
https://dolorendo.com/product/comprar-demerol/
https://dolorendo.com/product/comprar-amlodipine/
https://dolorendo.com/product/comprar-etizolam/
https://dolorendo.com/product/comprar-fentanilo-en-linea/
https://dolorendo.com/product/comprar-flakka-a-pvp/
https://dolorendo.com/product/comprar-heroina-en-linea/
https://dolorendo.com/product/comprar-metanfetaminas-en-linea/
https://dolorendo.com/product/comprar-micro-mushrooms/
https://dolorendo.com/product/comprar-norco-en-linea/
https://dolorendo.com/product/comprar-polvo-nembutal/
https://dolorendo.com/product/trenarapid-10x-1ml/
https://dolorendo.com/product/compre-nembutal-liquido/
https://dolorendo.com/product/comprar-psilocybe-cubensis-b/
https://dolorendo.com/product/comprar-quaaludes/
https://dolorendo.com/product/comprar-rubifen-espana/
https://dolorendo.com/product/comprar-soma-en-linea/
https://dolorendo.com/product/comprar-tilidin-en-linea/
https://dolorendo.com/product/comprar-trenbolone-enanthate/
https://dolorendo.com/product/comprar-trankimazin/
https://dolorendo.com/product/comprar-ultram-en-linea/
https://dolorendo.com/product/comprar-vicodin-en-linea/
https://dolorendo.com/product/comprar-xanax-verde/
https://dolorendo.com/product/comprar-xanax/

comprar Oxycodone
comprar Oxycodone Mexico
comprar pastillas nembutal
comprar oramorph sr
comprar dilaudid
comprar cristal mdma
comprar seconal sodium
comprar 4-aco dmt
comprar 5-meo dmt
comprar acetaminofen codeina
comprar adderall
comprar adipex
comprar alphabol
comprar ambien en-linea
comprar golden-teacher
comprar buprenorfine-en-linea
comprar cianuro-de-sodio
comprar cocaina
comprar demerol
comprar desoxyn-en-linea
comprar dexedrina
comprar dmt-en-linea
comprar amlodipine
comprar etizolam
comprar fentanilo en-linea
comprar flakka-a-pvp
comprar heroina en-linea
comprar ketamina
comprar klonopin
comprar metanfetaminas-en-linea
comprar micro-mushrooms
comprar morfina
comprar ritalin
comprar norco-en-linea
comprar Oxycodone en-linea
comprar Oxycodone
comprar oxynorm en-linea
comprar oxycontin en-linea
comprar percocet en-linea
comprar polvo nembutal
comprar trenarapid
comprar nembutal-liquido
comprar psilocybe-cubensis
comprar quaaludes
comprar rubifen espana
comprar soma en-line
comprar suboxone en-linea
comprar subutex en-linea
comprar tilidin en-linea
comprar trenbolone enanthate
comprar trankimazin
comprar ultram-en-linea
comprar vicodin en-linea
comprar xanax verde
comprar xanax
comprar Oxycodone USA
comprar vyvanse Canada

https://acquistaossicodone.eu/
https://acquistaossicodone.eu/product/
https://acquistaossicodone.eu/product/acquista-4-aco-dmt/
https://acquistaossicodone.eu/product/acquista-5-meo-dmt/
https://acquistaossicodone.eu/product/acquista-adderall-online/
https://acquistaossicodone.eu/product/acquista-adipex/
https://acquistaossicodone.eu/product/acquista-ambien-online/
https://acquistaossicodone.eu/product/acquista-buprenorfina-online/
https://acquistaossicodone.eu/product/acquista-cianuro-di-sodio/
https://acquistaossicodone.eu/product/acquista-flakka-a-pvp/
https://acquistaossicodone.eu/product/acquista-desoxyn/
https://acquistaossicodone.eu/product/acquista-dexedrine/
https://acquistaossicodone.eu/product/acquista-dmt-online/
https://acquistaossicodone.eu/product/acquista-fentanil-online/
https://acquistaossicodone.eu/product/acquista-la-morfina/
https://acquistaossicodone.eu/product/acquista-la-polvere-di-ketamina/
https://acquistaossicodone.eu/product/acquista-lsd/
https://acquistaossicodone.eu/product/acquista-mdma-crystal/
https://acquistaossicodone.eu/product/acquista-micro-funghi/
https://acquistaossicodone.eu/product/acquista-nembutal-liquid/
https://acquistaossicodone.eu/product/acquista-quaaludes/
https://acquistaossicodone.eu/product/acquista-vicodin/
https://acquistaossicodone.eu/product/acquista-subutex/
https://acquistaossicodone.eu/product/acquista-vyvanse/
https://acquistaossicodone.eu/product/buy-etizolam-usa/
https://acquistaossicodone.eu/product/acquista-ossicodone/
https://acquistaossicodone.eu/product/acquista-efedrina-hcl/
https://acquistaossicodone.eu/product/acquistare-tramadol-online/
https://acquistaossicodone.eu/product/acquista-addyi-online/
https://acquistaossicodone.eu/product/acquista-oxycontin/
https://acquistaossicodone.eu/products/
https://acquistaossicodone.eu/product/acquista-percocet/
https://acquistaossicodone.eu/product/acquista-pillole-di-nembutale/
https://acquistaossicodone.eu/product/acquista-pillole-suboxone/
https://acquistaossicodone.eu/product/acquista-polvere-nembutale/
https://acquistaossicodone.eu/product/acquista-psilocybe-cubensis-b/
https://acquistaossicodone.eu/product/buy-methamphentamine/
https://acquistaossicodone.eu/product/buy-secona-sodium/
https://acquistaossicodone.eu/product/acquista-soma-carisoprodol/
https://acquistaossicodone.eu/product/funghi-dorati-dellinsegnante
https://acquistaossicodone.eu/product/strisce-di-subossone/
https://acquistaossicodone.eu/product/strisce-di-subossone/
https://acquistaossicodone.eu/product/acquista-alphabol-cr-25mg/
https://acquistaossicodone.eu/product/acquista-tren-a-online/
https://acquistaossicodone.eu/product/acquista-trenarapid-online/
https://acquistaossicodone.eu/product/acquista-trenbolone-enanthate/
https://acquistaossicodone.eu/product/acquista-phentermine-italia/

acquista oxycontin
acquista 4 aco dmt
acquista 5 meo dmt
acquista adderall online
acquista ambien online
acquista buprenorfina online
acquista di sodio
acquista desoxyn
acquista dexedrine
acquista dilaudid pill
acquista dmt online
acquista fentanil online
acquista la morfina
acquista ketamina
acquista lsd
acquista mdma crystal
acquista micro funghi
acquista nembutal liquid
acquista-polvere nembutale
acquista polvere nembutale
acquista psilocybe cubensis b
acquista la-morphine
acquista phentermine italia
acquista oxycontin
acquista ossicodone
acquista subossone
acquista efedrina hcl
acquista suboxone
acquista subutex
acquista quaaludes
acquista vicodin
acquista vyvanse
https://onlinevapesshop.com/
https://onlinevapesshop.com/product/
https://onlinevapesshop.com/product/buy-phentermine-online/
https://onlinevapesshop.com/product/buy-adipex-online/
https://onlinevapesshop.com/product/buy-oxynorm-online/
https://onlinevapesshop.com/product/buy-oxycontin-online/
https://onlinevapesshop.com/product/buy-adderall-online-3/
https://onlinevapesshop.com/product/buy-adderall-online-2/
https://onlinevapesshop.com/product/buy-celexa-online/
https://onlinevapesshop.com/product/buy-concerta-online/
https://onlinevapesshop.com/product/buy-desoxyn-5mg-online/
https://onlinevapesshop.com/product/buy-dexedrine-online/
https://onlinevapesshop.com/product/buy-humatrope-pen-online/
https://onlinevapesshop.com/product/buy-methamphentamine-online/
https://onlinevapesshop.com/product/buy-molly-pills-online/
https://onlinevapesshop.com/product/buy-ritalin-online/
https://onlinevapesshop.com/product/buy-bromazepam-online/
https://onlinevapesshop.com/product/buy-vyvanse-online/
https://onlinevapesshop.com/product/order-diazepam-online/
https://onlinevapesshop.com/product/buy-etizolam-online/
https://onlinevapesshop.com/product/buy-green-xanax-online/
https://onlinevapesshop.com/product/buy-kinz-injections-online/
https://onlinevapesshop.com/product-category/anti-anxiety/
https://onlinevapesshop.com/product/buy-klonopin-online/
https://onlinevapesshop.com/product/buy-mescaline-online/
https://onlinevapesshop.com/product/buy-valium-online/
https://onlinevapesshop.com/product/buy-xanax-online/
https://onlinevapesshop.com/product/buy-yellow-xanax-bars-online/
https://onlinevapesshop.com/product/buy-zopiclone-online/
https://onlinevapesshop.com/product/buy-botox-online/
https://onlinevapesshop.com/product/buy-cbd-oil-online/
https://onlinevapesshop.com/product/buy-diclazepam-online/
https://onlinevapesshop.com/product/buy-liquid-red-mercury-online/
https://onlinevapesshop.com/product/buy-mdma-crystal-online/
https://onlinevapesshop.com/product/buy-phenylacetone-oil-online/
https://onlinevapesshop.com/product/buy-nembutal-pentobarbital-liqu...
https://onlinevapesshop.com/product/buy-piperonyl-methyl-ketone/
https://onlinevapesshop.com/product/buy-anavar-oxandrolone-online/
https://onlinevapesshop.com/product/buy-ssd-chemical-solution/
https://onlinevapesshop.com/product/buy-ayurvedic-urea-online/
https://onlinevapesshop.com/product/buy-dxn-code-strike-online/
https://onlinevapesshop.com/product/buy-deca-durabolin-online/
https://onlinevapesshop.com/product/buy-viagra-online/
https://onlinevapesshop.com/product/buy-genius-test-online/
https://onlinevapesshop.com/product/buy-viagra-online/
https://onlinevapesshop.com/product-category/growth-hormones/
https://onlinevapesshop.com/product/buy-viagra-online/
https://onlinevapesshop.com/product/buy-ketamine-liquid-online/
https://onlinevapesshop.com/product/buy-ketamine-powder-online/
https://onlinevapesshop.com/product/buy-methoxetamine-online/
https://onlinevapesshop.com/product/buy-methylone-crystals-online/
https://onlinevapesshop.com/product/buy-potassium-cyanide-online/
https://onlinevapesshop.com/product/buy-acetaminophen-online/
https://onlinevapesshop.com/product/buy-suboxone-online/
https://onlinevapesshop.com/product/buy-suboxone-online-2/
https://onlinevapesshop.com/product/buy-subutex-online/
https://onlinevapesshop.com/product/buy-ultram-online/
https://onlinevapesshop.com/product/buy-oxynorm-liquid/
https://onlinevapesshop.com/product/buy-anavar-oxandrolone-online/
https://onlinevapesshop.com/product/buy-arimidex-online/
https://onlinevapesshop.com/product/buy-botox-online/
https://onlinevapesshop.com/product/buy-demerol-online/
https://onlinevapesshop.com/product/buy-carfentanil-online/
https://onlinevapesshop.com/product/buy-dilaudid-online/
https://onlinevapesshop.com/product/buy-lortab-online/
https://onlinevapesshop.com/product/buy-cc-2/
https://onlinevapesshop.com/product/buy-oramorph-online/
https://onlinevapesshop.com/product/buy-percocet-online/
https://onlinevapesshop.com/product/buy-roxicodone-online/
https://onlinevapesshop.com/product/buy-soma-online/
https://onlinevapesshop.com/product/buy-tramadol-online/
https://onlinevapesshop.com/product/buy-vicodin-online/
https://onlinevapesshop.com/product/buy-vicoprofen-online/
https://onlinevapesshop.com/product/actavis-cough-syrup/
https://onlinevapesshop.com/product/buy-actavis-cough-syrup/
https://onlinevapesshop.com/product/buy-aliaxin-online/
https://onlinevapesshop.com/product/buy-fentanyl-citrate-online/
https://onlinevapesshop.com/product/buy-hydrocodone-online/
https://onlinevapesshop.com/product/buy-ketamine-hydrochloride-inje...
https://onlinevapesshop.com/product/buy-ketaset-online/
https://onlinevapesshop.com/product/buy-opana-40mg-online/
https://onlinevapesshop.com/product/buy-opana-40mg-online/

Your new post is loading...
Your new post is loading...
Scooped by I2BC Paris-Saclay
Scoop.it!

Members of gut microbiota prime insect immunity

Members of gut microbiota prime insect immunity | I2BC Paris-Saclay | Scoop.it

Burkholderia bacteria from the gut microbiota in the bean bug insect can cross the epithelium of the gut and trigger a protective systemic immune response that has no adverse effects on the insect fitness but confers a general protection against pathogens.

Insects lack acquired immunity and were thought to have no immune memory, but recent studies reported a phenomenon called immune priming, wherein sub-lethal dose of pathogens or non-pathogenic microbes stimulate immunity and prevent subsequential pathogen infection. Although the evidence for insect immune priming is accumulating, the underlying mechanisms are still unclear. The bean bug Riptortus pedestris acquires its gut microbiota from ambient soil and spatially structures them into a multispecies and variable community in the anterior midgut and a specific, mono-species Caballeronia symbiont population in the posterior region. We demonstrate that some particular Burkholderia strains colonizing the anterior midgut, stimulate systemic immunity by penetrating gut epithelia and migrating into the hemolymph. This hemolymph colonization and activated immunity, consisting of a humoral and a cellular response, has no negative effect on the host fitness, but on the contrary protected the insect from subsequent infection by pathogenic bacteria. Interruption of contact between the Burkholderia and epithelia of the gut weakened the host immunity back to pre-infection levels and made the insects again vulnerable to microbial infection, demonstrating that persistent acquisition of environmental bacteria is important to maintain an efficient immunity. This suggests that priming is only activated when it might be most helpful, e.g. when pathogen encounters are most likely in a microbially rich environment. Together, these findings not only highlight a role of environmental microbes in shaping insect immunity but also put a new, symbiotic perspective on bacterial intestinal barrier breaching and hemolymph colonization, which has been generally viewed only as a pathogenic phenomenon.

More information: https://doi.org/10.1073/pnas.2315540121

Contact : Peter MERGAERT <peter.mergaert@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

JAK-STAT-dependent contact between follicle cells and the oocyte controls Drosophila anterior-posterior polarity and germline development

JAK-STAT-dependent contact between follicle cells and the oocyte controls Drosophila anterior-posterior polarity and germline development | I2BC Paris-Saclay | Scoop.it

The authors identified a population of somatic cells in Drosophila follicles that elaborate filopodia penetrating the oocyte, thereby maintaining the contact between the two tissues. This is essential to control polarity and germline development of the future embryo.

The number of embryonic primordial germ cells is determined, in Drosophila, by the quantity of germ plasm, whose assembly starts in the posterior region of the oocyte during oogenesis. Here, we report that extending JAK-STAT activity in the posterior somatic follicular epithelium leads to an excess of primordial germ cells in the future embryo. We show that JAK-STAT signaling is necessary for the differentiation of approximately 20 specialized follicle cells maintaining tight contact with the oocyte. These cells define, in the underlying posterior oocyte cortex, the anchoring of the germ cell determinant oskar mRNA. We reveal that the apical surface of these posterior anchoring cells extends long filopodia penetrating the oocyte. We identify two JAK-STAT targets in these cells that are each sufficient to extend the zone of contact with the oocyte, thereby leading to production of extra primordial germ cells. JAK-STAT signaling thus determines a fixed number of posterior anchoring cells required for anterior-posterior oocyte polarity and for the development of the future germline.

More information: https://doi-org.insb.bib.cnrs.fr/10.1038/s41467-024-45963-z

Contact: Marianne MALARTRE <marianne.malartre@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Activity of MukBEF for chromosome management in E. coli and its inhibition by MatP

Activity of MukBEF for chromosome management in E. coli and its inhibition by MatP | I2BC Paris-Saclay | Scoop.it

The MukBEF condensin of E. coli loads at the replication fork and is unloaded at the Ter region by MatP.

Structural maintenance of chromosomes (SMC) complexes share conserved structures and serve a common role in maintaining chromosome architecture. In the bacterium Escherichia coli, the SMC complex MukBEF is necessary for rapid growth and the accurate segregation and positioning of the chromosome, although the specific molecular mechanisms involved are still unknown. Here, we used a number of in vivo assays to reveal how MukBEF controls chromosome conformation and how the MatP/matS system prevents MukBEF activity. Our results indicate that the loading of MukBEF occurs preferentially on newly replicated DNA, at multiple loci on the chromosome where it can promote long-range contacts in cis even though MukBEF can promote long-range contacts in the absence of replication. Using Hi-C and ChIP-seq analyses in strains with rearranged chromosomes, the prevention of MukBEF activity increases with the number of matS sites and this effect likely results from the unloading of MukBEF by MatP. Altogether, our results reveal how MukBEF operates to control chromosome folding and segregation in E. coli.

More information: https://elifesciences.org/articles/91185

Contact: Stéphane DUIGOU <stephane.duigou@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

 "Jeudis de la Recherche" at I2BC

 "Jeudis de la Recherche" at I2BC | I2BC Paris-Saclay | Scoop.it

As part of the "Jeudis de la Recherche" organized by the COMPAS (Paris-Saclay University), the CNRS and the town of Gif sur Yvette, Sylvie Lautru's team (I2BC, Microbiology Department) welcomed around twenty people to take part in 5 workshops on the theme of "Antibiotics and the microbial response: a never-ending battle". Thanks to the very interactive format, participants who were very interested in this topical issue, asked many questions and exchanged a lot with the research team.

https://www.ville-gif.fr/215/que-faire-a-gif/culture/conferences/jeudis-de-la-recherche.htm

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

EMBO conference "Molecular Biology of Archaea" 23-27th of june 2024 in Palaiseau (near Paris)! 

EMBO conference "Molecular Biology of Archaea" 23-27th of june 2024 in Palaiseau (near Paris)!  | I2BC Paris-Saclay | Scoop.it

The registration in now open for the next EMBO conference "Molecular Biology of Archaea" that will take place near Paris (Palaiseau) on 23-27th of june 2024! 

Archaea are fascinating organisms with a bacteria-like morphology, but information-processing systems that are homologous to eukaryotic counterparts, for instance replication, transcription and translation. Recently, novel groups of archaea (e.g. Asgard archaea) have been discovered that represent the closest living relatives to eukaryotes and shed new light on their evolution. Archaeal research has led to seminal change-of-concept mechanistic discoveries in the area of molecular biology, and many studies are currently aiming to unravel the global environmental impact of archaea. Their viruses have a remarkable diversity of morphotypes, exceeding that of bacterial or eukaryotic viruses.The EMBO Workshop on Molecular biology of Archaea will cover cutting-edge research in various fields with a focus on archaeal molecular biology, evolution, and ecology and their interconnections. The proposed talks will present data at different scales ranging from single molecule and structural studies to archaeal physiology, metabolism and ecological impact. This is of high interest as molecular studies of archaea are a very active field, reflecting the wealth of metagenomics information revealing novel biology that can now be addressed by the latest experimental and computational techniques.

all information:

https://meetings.embo.org/event/24-archaea

contact: Tamara BASTA-LE BERRE <tamara.basta@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Transposon sequencing reveals genes enabling insect gut colonization by the symbiont Caballeronia insecticola

Transposon sequencing reveals genes enabling insect gut colonization by the symbiont Caballeronia insecticola | I2BC Paris-Saclay | Scoop.it

High-througput genetic screens with Tn-seq in an insect gut bacterium reveals gut-derived nutrients consumed by the symbiont.

Caballeronia insecticola is a bacterium belonging to the Burkholderia sensu lato, able to colonize multiple environments like soils and the gut of the bean bug Riptortus pedestris. We constructed a saturated Himar1 mariner transposon library and revealed by transposon-sequencing (Tn-seq) that 498 protein-coding genes constitute the essential genome of C. insecticola for growth in free-living conditions. By comparing essential gene sets of C. insecticola and seven related Burkholderia s.l. strains, only 120 common genes were identified indicating that a large part of the essential genome is strain-specific. In order to reproduce specific nutritional conditions that are present in the gut of R. pedestris, we grew the mutant library in minimal media supplemented with candidate gut nutrients and identified several condition-dependent fitness-defect genes by Tn-seq. To validate the robustness of the approach, insertion mutants in six fitness genes were constructed and their growth-deficiency in media supplemented with the corresponding nutrient was confirmed. The mutants were further tested for their efficiency in R. pedestris gut colonization, confirming that gluconeogenic carbon sources, taurine and inositol, are nutrients consumed by the symbiont in the gut. Thus, our study provides insights about specific contributions provided by the insect host to the bacterial symbiont.

More information: https://doi.org/10.1093/ismeco/ycad001

Contact: Peter MERGAERT <peter.mergaert@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

The stringent response is strongly activated in the high antibiotic producer, Streptomyces coelicolor

The stringent response is strongly activated in the high antibiotic producer, Streptomyces coelicolor | I2BC Paris-Saclay | Scoop.it

The stringent response controls positively antibiotic biosynthesis. Antibiotics are thus part of the stringent response.

In most bacteria, the stringent response (SR) was initially characterized as a response to nitrogen (N) limitation resulting into the depletion of aminoacylated tRNAs leading to the stalling of ribosomes on mRNA. The recruitment of the ppGpp synthetase, RelA, at the stalled ribosomes activates (p)ppGpp synthesis from GTP. ppGpp that is the mediator of the SR controls negatively, at the transcriptional and translational levels, the expression of most ribosomal proteins leading to the down regulation of the translational process and thus of growth.
The model strains Streptomyces coelicolor (SC) and Streptomyces lividans (SL), strong and weak producers of the same antibiotics, respectively, were grown in condition of phosphate (Pi) limitation or proficiency and the abundance of proteins of their translational apparatus was compared. This study revealed that the expression of RelA was induced in Pi limitation suggesting that, besides N limitation, Pi limitation also contributes to the triggering of the SR. Interestingly, most proteins of the translational apparatus had a similar or slightly higher abundance in SL than in SC, in Pi limitation whereas most of these proteins were far more abundant in SL than in SC, in Pi proficiency. This indicated an alleviation of the SR in Pi proficiency in SL, but not in SC. This suggested an alteration of Pi up-take and/or Pi-mediated regulation in SC whose molecular basis remain to be elucidated.
Interestingly, the production of specialized metabolites in SC (CDA, RED and ACT) is usually concomitant of phases of growth slow down and it is known that ppGpp controls positively the expression of their biosynthetic pathways. Their production could thus be considered as part of the SR. Indeed, these metabolites were proposed to regulate negatively, through different processes, the energetic metabolism and thus the generation of ATP, in SC, a process that might contribute to the slower growth rate of SC compared to SL.

More information: https://www.sciencedirect.com/science/article/pii/S0923250823001547?via%3Dihub

Contact: Marie-Joëlle VIROLLE <marie-joelle.virolle@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Nikon presents the AX-NSPARC at Imagerie-Gif - From January 30 to February 9 -

Nikon presents the AX-NSPARC at Imagerie-Gif - From January 30 to February 9 - | I2BC Paris-Saclay | Scoop.it

Nikon is presenting its latest confocal microscope to the Paris-Saclay community, equipped with a new detector for very high-resolution images (XY : 100 nm).

From January 30 to February 9, 8 days of demonstrations on the Gif Imaging platform will enable you to test the microscope with your own samples .

Don't hesitate to come and take advantage of this opportunity.

More information: here

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Antigen self-anchoring onto bacteriophage T5 capsid-like particles for vaccine design

Antigen self-anchoring onto bacteriophage T5 capsid-like particles for vaccine design | I2BC Paris-Saclay | Scoop.it

Self-anchoring of large antigens onto Capsid-Like Particles derived from bacteriophage T5 paves the way for the development of a new vaccination platform that is highly immunogenic without the need for extrinsic adjuvant.

The constant need for immunization to prevent life-threatening diseases worldwide is urging the search for new vaccines. The promises of vaccines based on virus-like particles stimulate demand for universal non-infectious virus-like platforms that can be efficiently grafted with large antigens. In this study, we harnessed the modularity and extreme affinity of the decoration protein pb10 for the capsid of bacteriophage T5 to design a novel Ag delivery platform. DNA-free T5 capsid-like particles (T5-CLP) were decorated with chimeric proteins formed of pb10 fused to the model antigen ovalbumin (Ova). SPR experiments demonstrated that these proteins retained picomolar affinity for T5-CLP, while cryo-EM studies attested to the full occupancy of the 120 capsid binding sites. Mice immunisation with CLP-bound pb10-Ova chimeras elicited strong long-lasting anti-Ova humoral responses involving a large panel of isotypes, as well as CD8+ T cell responses, without any extrinsic adjuvant. Therefore, T5-CLP constitutes a unique DNA-free bacteriophage capsid able to display a regular array of large antigens through highly efficient chemical-free anchoring. Its ability to elicit robust immune responses paves the way for further development of this novel vaccination platform.

More information: https://www.nature.com/articles/s41541-023-00798-5

Contact: Pascale BOULANGER <pascale.boulanger-biard@i2bc.paris-saclay.fr>

 
 
No comment yet.
Rescooped by I2BC Paris-Saclay from Life Sciences Université Paris-Saclay
Scoop.it!

Conférence Cyclope : Les Protéines sont Partout ! - mardi 30 janvier 2024

Conférence Cyclope : Les Protéines sont Partout ! - mardi 30 janvier 2024 | I2BC Paris-Saclay | Scoop.it

On les trouve chez les animaux comme chez les plantes, les bactéries ou les virus. Elles permettent le battement régulier de votre cœur, la digestion de votre dernier repas, maintiennent votre corps à une température constante, participent à la lutte contre les infections qui vous menacent et bien plus encore...

 

Les protéines sont partout où la vie existe et la science les étudie depuis des décennies, mais elles sont si nombreuses et si diverses que leur monde reste encore à explorer.

 

Nous vous invitons à découvrir ces recherches passionnantes en compagnie de Marie-Hélène Le Du, chercheuse CEA à l'Institut de Biologie Intégrative de la Cellule – I2BC (DRF/Joliot/I2BC).

 

RDV le mardi 30 janvier 2024 à 20h.

 

Entrée libre sous réserve de places disponibles (le nombre de places est limité à 280).

 

Vous pourrez aussi suivre cette conférence en direct sur la chaîne Youtube du CEA.


Via Life Sciences UPSaclay
No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Visualizing the DNA repair process by a photolyase at atomic resolution

Visualizing the DNA repair process by a photolyase at atomic resolution | I2BC Paris-Saclay | Scoop.it

Molecular movies? No problem for time-resolved serial femtosecond X-ray crystallography! We have obtained 18 snapshots visualizing the whole DNA repair by a photolyase: from the initial electron transfer to the active site recovery and DNA reannealing.

Photolyases, a ubiquitous class of flavoproteins, use blue light to repair DNA photolesions. In this work, we determined the structural mechanism of the photolyase-catalyzed repair of a cyclobutane pyrimidine dimer (CPD) lesion using time-resolved serial femtosecond crystallography (TR-SFX). We obtained 18 snapshots that show time-dependent changes in four reaction loci. We used these results to create a movie that depicts the repair of CPD lesions in the picosecond-to-nanosecond range, followed by the recovery of the enzymatic moieties involved in catalysis, completing the formation of the fully reduced enzyme-product complex at 500 nanoseconds. Finally, back-flip intermediates of the thymine bases to reanneal the DNA were captured at 25 to 200 microseconds. Our data cover the complete molecular mechanism of a photolyase and, importantly, its chemistry and enzymatic catalysis at work across a wide timescale and at atomic resolution.

More information: https://www.science.org/doi/10.1126/science.add7795

Contact: Pavel MULLER  <pavel.muller@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

First anti-CRISPR protein that inhibits the CRISPR-Cas defense system in Clostridioides difficile

First anti-CRISPR protein that inhibits the CRISPR-Cas defense system in Clostridioides difficile | I2BC Paris-Saclay | Scoop.it

CRISPR-Cas adaptive immunity defends prokaryotes against their viruses named phages. In response, phages have evolved counter defense strategies to fight back. This study describes the identification of a phage protein to evade CRISPR-Cas immunity in a human pathogen Clostridioides difficile.

Clostridioides difficile is the widespread anaerobic spore-forming bacterium that is a major cause of potentially lethal nosocomial infections associated with antibiotic therapy worldwide. Due to the increase in severe forms associated with a strong inflammatory response and higher recurrence rates, a current imperative is to develop synergistic and alternative treatments of C. difficile infections. In particular, phage therapy is regarded as a potential substitute for existing antimicrobial treatments. However, it faces challenges because C. difficile have highly active CRISPR-Cas immunity, which may be a specific adaptation to phage-rich and highly crowded gut environment. To overcome this defense, C. difficile phages must employ anti-CRISPR mechanisms. Here, we present the first anti-CRISPR protein that inhibits the CRISPR-Cas defense system in this pathogen. Our work offers insights into the interactions between C. difficile and its phages, paving the way for future CRISPR-based applications and development of effective phage therapy strategies combined with the engineering of virulent C. difficile infecting phages.

More information: doi: 10.1128/msphere.00401-23 

Contact: Olga SOUTOURINA <olga.soutourina@i2bc.paris-saclay.fr> 

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

3D models of fungal chromosomes to enhance visual integration of omics data

3D models of fungal chromosomes to enhance visual integration of omics data | I2BC Paris-Saclay | Scoop.it

It has become easier to build 3D models of the entire genome based on Hi-C data, and thus benefit from the methodology and visualization tools developed for structural biology. In this paper, we show how seeing the spatial organization of chromosomes can bring new perspectives to omics data integration.

The functions of eukaryotic chromosomes and their spatial architecture in the nucleus are reciprocally dependent. Hi-C experiments are routinely used to study chromosome 3D organization by probing chromatin interactions. Standard representation of the data has relied on contact maps that show the frequency of interactions between parts of the genome. In parallel, it has become easier to build 3D models of the entire genome based on the same Hi-C data, and thus benefit from the methodology and visualization tools developed for structural biology. 3D modeling of entire genomes leverages the understanding of their spatial organization. However, this opportunity for original and insightful modeling is underexploited. In this paper, we show how seeing the spatial organization of chromosomes can bring new perspectives to omics data integration. We assembled state-of-the-art tools into a workflow that goes from Hi-C raw data to fully annotated 3D models and we re-analysed public omics datasets available for three fungal species. Besides the well-described properties of the spatial organization of their chromosomes (Rabl conformation, hypercoiling and chromosome territories), our results highlighted (i) in Saccharomyces cerevisiae, the backbones of the cohesin anchor regions, which were aligned all along the chromosomes, (ii) in Schizosaccharomyces pombe, the oscillations of the coiling of chromosome arms throughout the cell cycle and (iii) in Neurospora crassa, the massive relocalization of histone marks in mutants of heterochromatin regulators. 3D modeling of the chromosomes brings new opportunities for visual integration of omics data. This holistic perspective supports intuition and lays the foundation for building new concepts.

More information: https://academic.oup.com/nargab/article/5/4/lqad104/7458894

Contact: Gaëlle LELANDAIS <gaelle.lelandais@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Bettencourt-Schueller Foundation seminar on Art & Science: How does creativity emerge?

Bettencourt-Schueller Foundation seminar on Art & Science: How does creativity emerge? | I2BC Paris-Saclay | Scoop.it

Chloé @Chl0e_Girard and Daan @DaanNoordermeer were invited to an interdisciplinary workshop organized by the Bettencourt-Schueller Foundation @Fondation_BS about creativity as motor for scientific research.

A 3-days seminar was organized by the Bettencourt-Schueller Foundation at the Domaine de Chaumont-sur-Loire for former laureates (Prix Jeune Chercheur, Prix Impulsience, Prix Coups d’Elan pour la Recherche Française). This interdisciplinary seminar centered around creativity combined Arts & Science, the two main components of the foundation's patronage. The I2BC scientists participated in thematic workshops around Music, Mathematics, Visual Arts and Biology, presented by world-reknown artists and scientists. Daan Nordermeer was a recipient of the "Coup d'élan pour la recherche française”, while Chloé Girard received the "Prix jeune Chercheur", both in 2015.

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Cooperation between two modes for DNA replication initiation in the archaeon Thermococcus barophilus

Demonstration that diverse physiological states influence the mode of DNA replication initiation in the archaeon Thermococcus.

The mechanisms underpinning the replication of genomic DNA have recently been challenged in Archaea. Indeed, the lack of origin of replication has no deleterious effect on growth, suggesting that replication initiation relies on homologous recombination. Recombination-dependent replication (RDR) appears to be based on the recombinase RadA, which is of absolute requirement when no initiation origins are detected. The origin of this flexibility in the initiation of replication and the extent to which it is used in nature are yet to be understood. We combined deep sequencing and genetics to elucidate the dynamics of oriC utilization according to growth phases. We discovered that in Thermococcus barophilus, the use of oriC diminishes from the lag to the middle of the log phase, and subsequently increases gradually upon entering the stationary phase. Although oriC demonstrates no indispensability, RadA does exhibit essentiality. Notably, a knockdown mutant strain provides confirmation of the pivotal role of RadA in RDR for the first time. Thus, we demonstrate the existence of a tight combination between oriC utilization and homologous recombination to initiate DNA replication along the growth phases. Overall, this study demonstrates how diverse physiological states can influence the initiation of DNA replication, offering insights into how environmental sensing might impact this fundamental mechanism of life.

More information: https://pubmed.ncbi.nlm.nih.gov/38421162/

Contact: Jacques OBERTO <jacques.oberto@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

A genome-wide comprehensive analysis of nucleosome positioning in yeast

A genome-wide comprehensive analysis of nucleosome positioning in yeast | I2BC Paris-Saclay | Scoop.it

We show that the regulation and compartmentalisation of nucleosomal organisation require the concomitant actions of local and global processes that are maintained actively by energy consuming factors.

In eukaryotic cells, the one-dimensional DNA molecules need to be tightly packaged into the spatially constraining nucleus. Folding is achieved on its lowest level by wrapping the DNA around nucleosomes. Their arrangement regulates other nuclear processes, such as tran- scription and DNA repair. Despite strong efforts to study nucleosome positioning using Next Generation Sequencing (NGS) data, the mechanism of their collective arrangement along the gene body remains poorly understood. Here, we classify nucleosome distributions of protein-coding genes in Saccharomyces cerevisiae according to their profile similarity and analyse their differences using functional Principal Component Analysis. By decomposing the NGS signals into their main descriptive functions, we compared wild type and chromatin remodeler-deficient strains, keeping position-specific details preserved whilst considering the nucleosome arrangement as a whole. A correlation analysis with other genomic proper- ties, such as gene size and length of the upstream Nucleosome Depleted Region (NDR), identified key factors that influence the nucleosome distribution. We reveal that the RSC chromatin remodeler—which is responsible for NDR maintenance—is indispensable for decoupling nucleosome arrangement within the gene from positioning outside, which inter- fere in rsc8-depleted conditions. Moreover, nucleosome profiles in chd1Δ strains displayed a clear correlation with RNA polymerase II presence, whereas wild type cells did not indicate a noticeable interdependence. We propose that RSC is pivotal for global nucleosome orga- nisation, whilst Chd1 plays a key role for maintaining local arrangement.

More information: https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1011799

Contact: Arach GOLDAR <arach.goldar@i2bc.paris-saclay.fr>

No comment yet.
Rescooped by I2BC Paris-Saclay from Life Sciences Université Paris-Saclay
Scoop.it!

Portrait Jeune Chercheuse - Cécile Sauvanet, Professeure junior en Biologie Structurale

Portrait Jeune Chercheuse - Cécile Sauvanet, Professeure junior en Biologie Structurale | I2BC Paris-Saclay | Scoop.it

Cécile Sauvanet est titulaire d’une Chaire de Professeur Junior du CNRS et est affectée à l’Institut de Biologie Intégrative de la Cellule - I2BC (CNRS/CEA/UPSaclay) à Gif-sur-Yvette. Ses recherches portent sur les mécanismes régulant le transport intracellulaire des organites en particulier les mitochondries. Elle utilise des approches de biologie intégrative alliant la biologie cellulaire, la biochimie et la cryo-microscopie électronique (Cryo-EM).

 

Elle a effectué sa thèse de biochimie à l’Université de Bordeaux où son travail cherchait à caractériser la machinerie de fusion mitochondriale. Elle a pu montrer in vivo dans la levure Saccharomyces cerevisiae que des défauts bioénergétiques entrainaient l’inhibition spécifique de la fusion de la membrane mitochondriale interne. Elle a également caractérisé le rôle des mitofusines humaines dans la fusion mitochondriale grâce à des approches in vitro de biochimie et biophysique.

 

Elle a ensuite poursuivi sa formation post-doctorale tout d’abord à l’université de Cornell (Ithaca, NY, USA) dans le laboratoire d’Anthony Bretscher. Ses recherches portaient sur les protéines responsables de la formation et de la régulation des microvillosités au niveau du site apical des cellules épithéliales. Elle a ensuite rejoint l'équipe de Francesca Giordano à l'I2BC, où elle a participé à l’étude des sites de contact membranaire entre le réticulum endoplasmique, les mitochondries et les gouttelettes lipidiques.

 

Cécile a finalement rejoint le groupe de Dorit Hanein à l'Institut Pasteur où elle a concentré ses travaux sur le développement de méthodes de cryo-EM et cryo-tomographie qu’elle a utilisées pour étudier l'entrée du SARS-CoV-2 dans les cellules, les jonctions cellulaires ou encore la structure des protéines membranaires.

 

Depuis Septembre 2023, elle a rejoint l’I2BC et l’équipe « Biochimie structurale des microtubules, des kinésines et leurs cargos » co-dirigée par Julie Ménétrey et Benoît Gigant. Elle y développe sa propre thématique de recherche sur les mécanismes régulant le transport des mitochondries dans les neurones. L’objectif est de comprendre comment les mitochondries sont positionnées au bon moment, au bon endroit et dans la bonne quantité pour répondre aux besoins de la cellule.

 

« Je n'accepte plus les choses que je ne peux pas changer. Je change les choses que je ne peux pas accepter. » - Angela Davis

 

Contact : cecile.sauvanet@i2bc.paris-saclay.fr


Via Life Sciences UPSaclay
No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Prize "Relève de l'étoile" for the excellence of the research work carried out by Alexia Royer

Prize "Relève de l'étoile" for the excellence of the research work carried out by Alexia Royer | I2BC Paris-Saclay | Scoop.it

Alexia Royer received the prize "Relève de l'étoile" for her article “Clostridioides difficile S-Layer Protein A (SlpA) Serves as a General Phage Receptor” published in Microbiology Spectrum in February 2023.

Antibiotics have been used for more than 80 years to treat bacterial infections, but bacteria have developed resistance to these treatments, making them difficult to eradicate. One of the side effects of antibiotics is that they tend to kill a broad spectrum of bacteria, including “good bacteria” important for the proper functioning of the human body. The resulting bacterial imbalance, called dysbiosis, will open the door to opportunistic bacteria such as Clostridioides difficile. This bacterium is the main cause of severe diarrhea in industrialized countries. As the infection is now treated with antibiotics, which are themselves responsible for the infection, many relapses are reported. In the laboratories of Professor Louis-Charles Fortier and Professor Olga Soutourina, we are interested in phage therapy, which is a treatment based on the use of bacteria-killing viruses called bacteriophages. Phages have the advantage of being specific and targeting a species or a few bacterial strains unlike antibiotics. Thus, they could be used as an alternative or complementary therapy to antibiotics to treat patients in therapeutic failure. The key step to set up a phage therapy is to understand the mechanism of recognition of the bacteria by phages. For a phage to attack and kill a bacterium, it must first attach to a receptor on its surface. In the article, we identified the SlpA protein as the receptor on the surface of the bacteria that is targeted by phages. We have shown that the infection specificity of phages is linked to the presence of different forms of SlpA, called isoforms, each strain expressing one isoform. We also identified a domain of SlpA, named D2, playing a role in receptor recognition by certain phages. These data are essential because they improve our understanding of phage/bacteria interactions and make phage therapy possible one day against C. difficile infections.

https://frq.gouv.qc.ca/histoire-et-rapport/releve-etoile-jacques-genest-decembre-2023/

Alexia ROYER <alexia.royer@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Protein-protein interactions: how to push forward the limits of the revolutionary AlphaFold2 programme?

Protein-protein interactions: how to push forward the limits of the revolutionary AlphaFold2 programme? | I2BC Paris-Saclay | Scoop.it

AlphaFold2 is revolutionising protein structure prediction and structural biology practices. However, it may prove less effective for certain protein assemblies, particularly when they depend on intrinsically disordered regions. In an article published in Nature Communications, researchers from the I2BC show that applying a fragmentation strategy to the protein partners of such assemblies very significantly improves AlphaFold2’s prediction capacity.

Mapping protein-protein interaction networks is essential for understanding the dynamics of cellular functions and their cross-regulation. Precise knowledge of interaction sites makes it possible to specifically perturb the proteins in these networks and understand the synergies and competitions that ensure cell function.

Unfortunately, a great amount of structural information is still lacking to provide a detailed understanding of the organisation of interaction networks. The AlphaFold2 artificial intelligence programme has demonstrated a remarkable ability to predict the structures of protein assemblies that have co-evolved over long time scales. Its performance remained poorly characterised for assemblies involving intrinsically disordered regions, which often mediate transient and dynamic interactions during evolution.

In a study published in the journal Nature Communications, researchers from the AMIG team at the Institut de Biologie Intégrative de la Cellule – I2BC (CNRS/CEA/UPSaclay, Gif-sur-Yvette) have shown that AlphaFold2 performs poorly if large disordered regions are used directly for prediction (40% success rate). A protein fragmentation strategy was found to be particularly well adapted to predicting the interfaces between folded domains and small protein motifs that fold on contact with the partner. Applied on a large scale using the Jean Zay HPC infrastructure on more than 900 complexes, this strategy achieved a success rate of almost 90%, a very encouraging result for the systematic screening of protein interaction networks. Nevertheless, the study calls for vigilance with regard to the risks of detecting false positives, which will be at the heart of future developments in artificial intelligence strategies such as AlphaFold2.

More information: https://www.nature.com/articles/s41467-023-44288-7

Contact: Jessica ANDREANI and Raphaël GUEROIS  <jessica.andreani@i2bc.paris-saclay.fr> <raphael.guerois@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Composition of Poxvirus Core Revealed

Composition of Poxvirus Core Revealed | I2BC Paris-Saclay | Scoop.it

A collaboration between groups at I2BC, CSSB, MPI, and PEI, reveals the structure and the flexibility of A10 trimers that compose the palisade layer of the Vaccinia virus core encasing the viral genome. 

Vaccinia virus is the model for the family of poxviruses, however, the structure of the viral particle used to propagate infection is poorly understood. The group of Emmanuelle Quemin at I2BC together with collaborators at CSSB in Hamburg, MPI for Biophysics in Frankfurt, and PEI in Langen, have revealed the composition and architecture of Vaccinia virus core that encases the viral genome. Their findings have been published in Nature Structural & Molecular Biology.
By combining cryo-electron tomography with subtomogram averaging and AlphaFold2, the authors were able to identify components of the core of Vaccinia virus. During entry, there is the fusion of the viral and cellular membranes that lead to the subsequent release of the viral core inside the host cell. As these are rare and fast events difficult to tackle by cellular cryo electron tomography, the researchers studied the core both in situ and in vitro, using virusal particles treated with detergents to access so-called “naked” cores containing the viral genome still. In parallel to the large dataset obtained in vitro, entering cores found inside cells were also analysed under native conditions at CSSB cryo-EM facility directed by Kay Grünewald in Hamburg, Germany,
The four groups involved focused more specifically on the outer layer of the core called the palisade that displayed a dense and organized surface of tubular protrusions that we refer to as stakes. Their study determined that these protrusions are trimers of the viral protein A10, previously known as one of the major core proteins. Here, the stakes appeared as more randomly organized than reported in other recent published work and have an inherent flexibility.
While some poxviruses can spread in human populations as recently exemplified with the Mpox virus multi-country outbreak, improving our understanding of Vaccinia virus and its core sub-structure is key to shed light on conserved mechanisms of poxvirus infection and pathogenicity.

More information: https://www.nature.com/articles/s41594-024-01218-5

Contact: Emmanuelle QUEMIN <emmanuelle.quemin@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Toxoplasma membrane inositol phospholipid binding protein TgREMIND is essential for secretory organelle function and host infection

Toxoplasma membrane inositol phospholipid binding protein TgREMIND is essential for secretory organelle function and host infection | I2BC Paris-Saclay | Scoop.it

Apicomplexan parasites possess specialized secretory organelles called rhoptries, micronemes, and dense granules that play a vital role in host infection. In this study, we demonstrate that TgREMIND, a protein found in Toxoplasma gondii, is necessary for the biogenesis of rhoptries and dense granules. TgREMIND contains a Fes-CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain, which binds to membrane phospholipids, as well as a novel uncharacterized domain that we have named REMIND (regulator of membrane-interacting domain). Both the F-BAR domain and the REMIND are crucial for TgREMIND functions. When TgREMIND is depleted, there is a significant decrease in the abundance of dense granules and abnormal transparency of rhoptries, leading to a reduction in protein secretion from these organelles. The absence of TgREMIND inhibits host invasion and parasite dissemination, demonstrating that TgREMIND is essential for the proper function of critical secretory organelles required for successful infection by Toxoplasma.

More information: doi: 10.1016/j.celrep.2023.113601

Contact: Stanislas TOMAVO <stanislas.tomavo@i2bc.paris-saclay.fr>

 
No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Schizosaccharomyces pombe as a fundamental model for research on mitochondrial gene expression: Progress, achievements and outlooks

Schizosaccharomyces pombe as a fundamental model for research on mitochondrial gene expression: Progress, achievements and outlooks | I2BC Paris-Saclay | Scoop.it

This is a comprehensive and critical review on mitochondrial gene expression in fission yeast, presenting up-to-date knowledge, and emphasising numerous contributions of the unicellular model to both fundamental and biomedical research.

Schizosaccharomyces pombe (fission yeast) is an attractive model for mitochondrial research. The organism resembles human cells in terms of mitochondrial inheritance, mitochondrial transport, sugar metabolism, mitogenome structure, and dependence of viability on the mitogenome (the petite-negative phenotype). Transcriptions of these genomes produce only a few polycistronic transcripts, which then undergo processing as per the tRNA punctuation model. In general, the machinery for mitochondrial gene expression is structurally and functionally conserved between fission yeast and humans. Furthermore, molecular research on S. pombe is supported by a considerable number of experimental techniques and database resources. Owing to these advantages, fission yeast has significantly contributed to biomedical and fundamental research. Here, we review the current state of knowledge regarding S. pombe mitochondrial gene expression, and emphasise the pertinence of fission yeast as both a model and tool, especially for studies on mitochondrial translation.

More information: https://doi.org/10.1002/iub.2801

Contact: Nathalie BONNEFOY <nathalie.bonnefoy@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays

Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays | I2BC Paris-Saclay | Scoop.it

Meet me at MAM: optimization of a proximity ligation-3D image analysis protocol to quantify protein interactions at Mitochondria-Associated Endoplasmic Reticulum Membranes.

More information:  https://www.jove.com/fr/v/64750/visualization-quantification-endogenous-intra-organelle-protein

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Straining the root on and off triggers local calcium signaling

Straining the root on and off triggers local calcium signaling | I2BC Paris-Saclay | Scoop.it

Combining microfluidics and imaging, reveal that a pressure exerted on the root induces an elastic deformation and a calcium signal both at the onset and at the offset of the stimulation.

 How plant roots perceive mechanical cues encountered in the soil remains elusive. Combining microfluidics and imaging, we have shown that a pressure exerted on the root induces an elastic deformation and a calcium signal both at the onset and at the offset of the stimulation. Although the intensity of the calcium response increased with the pressure applied, successive stimuli led to a remarkable attenuation of the calcium signal. The calcium elevation was restricted to the tissue under pressure without propagation. This study published in Proceedings of the Royal Society B (https://doi.org/10.1098/rspb.2023.1462) contributes to elucidate the mechanisms of root adaptation to the mechanical cues generated by the soil.
This work was supported by the Région Ile de France through the DIM ELICIT program and by Saclay Plant Sciences through the DYNANO project.

More information: doi: 10.1128/msphere.00401-23 

Contact: Jean-Marie Frachisse – Sébastien Thomine <jean-marie.frachisse@i2bc.paris-saclay.fr> <sebastien.thomine@i2bc.paris-saclay.fr>

No comment yet.
Scooped by I2BC Paris-Saclay
Scoop.it!

Inter-generational nuclear crosstalk controls the progression of the Paramecium developmental program

Inter-generational nuclear crosstalk controls the progression of the Paramecium developmental program | I2BC Paris-Saclay | Scoop.it

Perturbing the Paramecium transcriptome during somatic development reveals the existence of internuclear feed-forward and feedback transcriptional regulatory loops in a multinucleate unicellular eukaryote.

The single-celled ciliate Paramecium tetraurelia harbors multiple nuclei within its cytoplasm: two germline micronuclei (MIC) dedicated to sexual reproduction and a somatic macronucleus (MAC) responsible for gene expression. During the sexual cycle, the parental MAC undergoes progressive degradation while, in the same cell, new MACs develop from copies of the zygotic MIC. Throughout this process, gene expression primarily occurs in the parental MAC, and clusters of developmentally regulated genes are successively switched on and off. Concomitantly, the genome of the new MACs is extensively rearranged and cleansed of its transposons and other DNA repeats, to become competent for gene expression.

New MAC development has long been known to be controled by the parental MAC, which expresses key genes involved in programmed genome rearrangement (PGR). In this study, RNA deep sequencing and bioinformatic analysis of differential gene expression reveal a reciprocal relationship between the two generations of MACs: the formation of the new MACs is essential for the proper induction of a subset of developmental genes. Later in the sexual cycle, if PGR is hindered in the new MACs, a group of genes partially overlapping the former subset is upregulated, and no longer switched off. Thus, the progression of new MAC development regulates the gene expression program in the parental MAC at different stages. The set of co-expressed genes identified during the course of this work establishes a list of potential novel actors, whose roles in PGR will be explored in future studies.

More information: https://doi.org/10.1093/nar/gkad1006

Contact: Olivier Arnaiz – Mireille Bétermier <olivier.arnaiz@i2bc.paris-saclay.fr> <mireille.betermier@i2bc.paris-saclay.fr>

No comment yet.