scholarly journals Memantine attenuated E. coli K1-induced tight junction injuries through inhibition of α7 nAChR-dependent pathway in vitro

2020 ◽  
Vol 101 ◽  
pp. 132
Author(s):  
H.S. Qiu ◽  
Z.T. Li ◽  
Q.X. Lin ◽  
Y.P. Cai ◽  
J. Lan ◽  
...  
Keyword(s):  
Tight Junction ◽  
E Coli ◽  
Α7 Nachr ◽  
Dependent Pathway

scholarly journals Enteroaggregative Escherichia coli Disrupts Epithelial Cell Tight Junctions

2010 ◽  
Vol 78 (11) ◽  
pp. 4958-4964 ◽  
Author(s):  
Maura C. Strauman ◽  
Jill M. Harper ◽  
Susan M. Harrington ◽  
Erik Juncker Boll ◽  
James P. Nataro
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Tight Junctions ◽  
Cell Model ◽  
Barrier Dysfunction ◽  
T84 Cells ◽  
E Coli ◽  
Eaec Strain ◽  
Epithelial Barrier Dysfunction

ABSTRACT Enteroaggregative Escherichia coli (EAEC) is responsible for inflammatory diarrhea in diverse populations, but its mechanisms of pathogenesis have not been fully elucidated. We have used a previously characterized polarized intestinal T84 cell model to investigate the effects of infection with EAEC strain 042 on tight junction integrity. We find that infection with strain 042 induces a decrease in transepithelial electrical resistance (TER) compared to uninfected controls and to cells infected with commensal E. coli strain HS. When the infection was limited after 3 h by washing and application of gentamicin, we observed that the TER of EAEC-infected monolayers continued to decline, and they remained low even as long as 48 h after the infection. Cells infected with the afimbrial mutant strain 042aafA exhibited TER measurements similar to those seen in uninfected monolayers, implicating the aggregative adherence fimbriae II (AAF/II) as necessary for barrier dysfunction. Infection with wild-type strain 042 induced aberrant localization of the tight junction proteins claudin-1 and, to a lesser degree, occludin. EAEC-infected T84 cells exhibited irregular shapes, and some cells became elongated and/or enlarged; these effects were not observed after infection with commensal E. coli strain HS or 042aafA. The effects on tight junctions were also observed with AAF/I-producing strain JM221, and an afimbrial mutant was similarly deficient in inducing barrier dysfunction. Our results show that EAEC induces epithelial barrier dysfunction in vitro and implicates the AAF adhesins in this phenotype.

Rho GTPase overactivation by E. coli CNF-1 disrupts epithelial tight junction structure and barrier function

2001 ◽  
Vol 120 (5) ◽  
pp. A110-A110
Author(s):  
A HOPKINS ◽  
S WALS ◽  
P VERKADE ◽  
P BOQUET ◽  
A NUSRAT
Keyword(s):  
Tight Junction ◽  
Barrier Function ◽  
Rho Gtpase ◽  
E Coli ◽  
Epithelial Tight Junction ◽  
Junction Structure

The Mechanism of Platelet Aggregation Induced by HLA-Related Antibodies

1996 ◽  
Vol 76 (05) ◽  
pp. 774-779 ◽  
Author(s):  
John T Brandt ◽  
Carmen J Julius ◽  
Jeanne M Osborne ◽  
Clark L Anderson
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Complement Activation ◽  
Thromboembolic Disease ◽  
Clinical Samples ◽  
Hla Antigen ◽  
Aggregation Response ◽  
Immune Mediated ◽  
Dependent Pathway

SummaryImmune-mediated platelet activation is emerging as an important pathogenic mechanism of thrombosis. In vitro studies have suggested two distinct pathways for immune-mediated platelet activation; one involving clustering of platelet FcyRIIa, the other involving platelet-associated complement activation. HLA-related antibodies have been shown to cause platelet aggregation, but the mechanism has not been clarified. We evaluated the mechanism of platelet aggregation induced by HLA-related antibodies from nine patients. Antibody to platelet FcyRIIa failed to block platelet aggregation with 8/9 samples, indicating that engagement of platelet FcyRIIa is not necessary for the platelet aggregation induced by HLA-related antibodies. In contrast, platelet aggregation was blocked by antibodies to human C8 (5/7) or C9 (7/7). F(ab’)2 fragments of patient IgG failed to induce platelet activation although they bound to HLA antigen on platelets. Intact patient IgG failed to aggregate washed platelets unless aged serum was added. The activating IgG could be adsorbed by incubation with lymphocytes and eluted from the lymphocytes. These results indicate that complement activation is involved in the aggregation response to HLA-related antibodies. This is the first demonstration of complement-mediated platelet aggregation by clinical samples. Five of the patients developed thrombocytopenia in relationship to blood transfusion and two patients developed acute thromboembolic disease, suggesting that these antibodies and the complement-dependent pathway of platelet aggregation may be of clinical significance.

Evidence that gene expression of ovarian follicular tight junction proteins is regulated in vivo and in vitro in cattle

2017 ◽  
Vol 95 (3) ◽  
pp. 1313 ◽  
Author(s):  
L. Zhang ◽  
L. F. Schütz ◽  
C. L. Robinson ◽  
M. L. Totty ◽  
L. J. Spicer
Keyword(s):  
Gene Expression ◽  
Tight Junction ◽  
Tight Junction Proteins ◽  
Junction Proteins

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Антимикробная активность лиофилизированного водного извлечения Caragana jubata (Pall.) Poir.

2020 ◽  
Vol 54 (3) ◽  
pp. 42-44
Author(s):  
Павел Алексеевич Какорин ◽  
Татьяна Владимировна Фатеева ◽  
Ольга Ивановна Терешкина ◽  
Ирина Борисовна Перова ◽  
Галина Владиславовна Раменская ◽  
...  
Keyword(s):  
E Coli

На основании ранее проведенных исследований установлен профиль флавоноидов лиофилизированного водного извлечения, полученного из побегов C. jubata. В связи с тем, что, согласно данным литературы, флавоноиды являются потенциальными ингибиторами микроорганизмов, проведено изучение антимикробной активности лиофилизата в опытах in vitro с использованием скринигового метода определения антимикробной активности для препаратов растительного происхождения. При изучении бактериостатической и фунгистатической активности в опытах in vitro использовали метод двукратного серийного разведения препаратов в жидких питательных средах. В результате исследования лиофилизированного водного извлечения караганы гривастой установлено наличие умеренной антимикробной активности в отношении всех изученных штаммов патогенных микроорганизмов: грамположительных и грамотрицательных бактерий (S. aureus, E. coli, P. vulgaris, P. aeruginosa), дрожжеподобных и мицелиальных грибов (C. albicans, M. canis). Полученные данные позволяют рекомендовать лиофилизированное водное извлечение караганы гривастой для создания на его основе лекарственных форм наружного применения для лечения заболеваний кожи и слизистых оболочек, связанных с бактериальным воспалительным процессом.

Влияние in vitro изолированного и сочетанного с антибактериальными средствами применения бовгиалуронидазы азоксимер на целостность бактериальной биопленки и жизнеспосоность микроорганизмов

2020 ◽  
Vol 83 (2) ◽  
pp. 38-44
Author(s):  
Е. Ю. Тризна ◽  
Д. Р. Байдамшина ◽  
Александр А. Виницкий ◽  
А. Р. Каюмов
Keyword(s):  
E Coli

Исследована способность лиофилизата бовгиалуронидазы азоксимера («Лонгидаза») разрушать бактериальные биопленки S. aureus, E. faecalis, E. coli, а также сочетанное действие препарата с антибактериальными средствами. Показано, что 2 ч инкубации бовгиалуронидазы азоксимер в концентрации 750 – 1500 МЕ/мл вызывает двукратное снижение биомассы матрикса зрелых биопленок E. faecalis и E. coli, и на 60 % — S. aureus. Данный ферментный препарат не влияет на образование бактериальных биопленок. При сочетанном применении с антибактериальными средствами препарат повышает их эффективность в отношении бактерий в составе биопленок. Так, концентрация ципро-флоксацина и амоксициллина, необходимая для снижения количества КОЕ на 3 порядка в биопленке E. faecalis, в присутствии бовгиалуронидазы азоксимера снижается в 16 раз (p < 0,05). В присутствии фермента в 16 раз меньшие концентрации цефуроксима, фосфомицина, ципрофлоксацина и амикацина достаточны для снижения количества КОЕ на 3 порядка в биопленке E. coli (p < 0,05), и в значительно меньшей концентрации цефуроксим оказывает бактерицидное действие на клетки в биопленке S. aureus (p < 0,05). Вероятно, бовгиалуронидаза азоксимер увеличивает проникновение антибактериальных средств к клеткам бактерий в биопленке, что обеспечивает потенцирование их антибактериального эффекта. Такое действие ферментного препарата позволяет снизить дозу и повысить безопасность антибактериальных средств при сохранении их эффективности.

Properties and Biotechnological Application of mutant Derivatives of Mini-intein PRP8 from Penicillium chrysogenum with Improved Control of C-terminal Processing

2019 ◽  
Vol 35 (6) ◽  
pp. 91-101
Author(s):  
F.A. Klebanov ◽  
S.E. Cheperegin ◽  
D.G. Kozlov
Keyword(s):  
Penicillium Chrysogenum ◽  
Protein Denaturation ◽  
Biologically Active ◽  
Cultivation Temperature ◽  
Target Proteins ◽  
E Coli ◽  
Complete Inactivation ◽  
Target Molecules ◽  
Proteins And Peptides

Mutant variants of mini-intein PRP8 from Penicillium chrysogenum (Int4b) with improved control of C-terminal processing were characterized. The presented variants can serve as a basis for self-removed polypeptide tags capable of carrying an affine label and allowing to optimize the process of obtaining target proteins and peptides in E. coli cells. They allow to synthesize target molecules in the composition of soluble and insoluble hybrid proteins (fusions), provide their afnne purification, autocatalytic processing and obtaining mature target products. The presented variants have a number of features in comparison with the known prototypes. In particular the mutant mini-intein Int4bPRO, containing the L93P mutation, has temperature-dependent properties. At cultivation temperature below 30 °C it allows the production of target molecules as part of soluble fusions, but after increasing of cultivation temperature to 37 °C it directs the most of synthesized fusions into insoluble intracellular aggregates. The transition of Int4bPRO into insoluble form is accompanied by complete inactivation of C-terminal processing. Further application of standard protein denaturation-renaturation procedures enable efficiently reactivate Int4bPRO and to carry out processing of its fusions in vitro. Two other variants, Int4b56 and Int4b36, containing a point mutation T62N or combination of mutations D144N and L146T respectively, have a reduced rate of C-terminal processing. Their use in E. coli cells allows to optimize the biosynthesis of biologically active target proteins and peptides in the composition of soluble fusions, suitable for afnne purification and subsequent intein-dependent processing without the use of protein denaturation-renaturation procedures. intein, fusion, processing, processing rate, gelonin The work was supported within the framework of the State Assignment no. 595-00003-19 PR.

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