Energetics of colicin import revealed by genetic cross-complementation between the Tol and Ton systems

2012 ◽  
Vol 40 (6) ◽  
pp. 1480-1485 ◽  
Author(s):  
Roland Lloubès ◽  
Emilie Goemaere ◽  
Xiang Zhang ◽  
Eric Cascales ◽  
Denis Duché
Keyword(s):  
Cell Envelope ◽  
Membrane Receptors ◽  
Target Cells ◽  
Transmembrane Helices ◽  
Tonb System ◽  
Group A ◽  
Group B ◽  
Colicin E9 ◽  
Import System ◽  
N Use

Colicins are bacterial toxins that parasitize OM (outer membrane) receptors to bind to the target cells, use an import system to translocate through the cell envelope and then kill sensitive cells. Colicins classified as group A (colicins A, E1–E9, K and N) use the Tol system (TolA, TolB, TolQ and TolR), whereas group B colicins (colicins B, D, Ia, M and 5) use the ExbB–ExbD–TonB system. Genetic evidence has suggested that TolQ and ExbB, as well as TolR and ExbD, are interchangeable, whereas this is not possible with TolA and TonB. Early reports indicated that group B colicin uptake requires energy input, whereas no energy was necessary for the uptake of the pore-forming colicin A. Furthermore, energy is required to dissociate the complex formed with colicin E9 and its cognate immunity protein during the import process. In the present paper, we detail the functional phenotypes and colicin-sensitivity results obtained in tolQ and exbB mutants and cross-complementation data of amino acid substitutions that lie within ExbB or TolQ TMHs (transmembrane helices). We also discuss on a specific phenotype that corresponds to group A colicin-sensitivity associated with a non-functional Tol system.

scholarly journals Different Expressions of IL-1 TNF-α P-selectin mRNA by Endothelial Cells after Vein Thrombosis

2019 ◽  
Author(s):  
Jiasheng Xu ◽  
Kaili Liao ◽  
Weimin Zhou
Keyword(s):  
Endothelial Cells ◽  
Early Stage ◽  
Early Period ◽  
Target Cells ◽  
Mrna Levels ◽  
Vein Thrombosis ◽  
Tnf Α ◽  
Group A ◽  
Group B ◽  
Porcine Endothelial Cells

[Abstract]ObjectiveExperiments were designed to compare the expressions of IL-1 TNF-α P-selectin mRNA by porcine endothelial cells after vein thrombosis.MethodsIVC under the renal vein of 20 porcines were ligated to induce thrombosis modes. These thrombosed veins were divided into three groups:group A-one day after thrombosis, group B-four days after thrombosis and group C-seven days after thrombosis. The other pigs were given the shame operation as a contro group (group D). The mRNA levels of IL-1、 TNF-α and P-selectin expressed by porcine endothelial cells in three groups were analy sed by semi quantitative RT-PCR. Endothelial cells were harvested with collagenase II.ResultsThe purity of endothelial cells harvested was 99.42 ±0.07. The expression of IL-1 was detained only in group A while TNF-αreached its peak in group B(P<0.05) and P-selectin increased gradually with the days passing by(P<0.05).ConclusionEndothelial cells are not only the target cells of inflammatory mediators, but also can express a variety of active factors to promote venous thrombosis. Expression of TNF-α mRNA is increased gradually in the early period of vein thrombosis whileP-selectin in the acute period; IL-1 mRNA was transiently expressed only in the early stage of thrombosis.

scholarly journals Colicin E2 Is Still in Contact with Its Receptor and Import Machinery When Its Nuclease Domain Enters the Cytoplasm

2007 ◽  
Vol 189 (11) ◽  
pp. 4217-4222 ◽  
Author(s):  
Denis Duché
Keyword(s):  
Escherichia Coli ◽  
Envelope Protein ◽  
Cytoplasmic Membrane ◽  
Outer Membrane Receptor ◽  
Nuclease Domain ◽  
Tonb System ◽  
Group A ◽  
Colicin E2 ◽  
Group B ◽  
Time Required

ABSTRACT Colicins reach their targets in susceptible Escherichia coli strains through two envelope protein systems: the Tol system is used by group A colicins and the TonB system by group B colicins. Colicin E2 (ColE2) is a cytotoxic protein that recognizes the outer membrane receptor BtuB. After gaining access to the cytoplasmic membrane of sensitive Escherichia coli cells, ColE2 enters the cytoplasm to cleave DNA. After binding to BtuB, ColE2 interacts with the Tol system to reach its target. However, it is not known if the entire colicin or only the nuclease domain of ColE2 enters the cell. Here I show that preincubation of ColE2 with Escherichia coli cells prevents binding and translocation of pore-forming colicins of group A but not of group B. This inhibition persisted even when cells were incubated with ColE2 for 30 min before the addition of pore-forming colicins, indicating that ColE2 releases neither its receptor nor its translocation machinery when its nuclease domain enters the cells. These competition experiments enabled me to estimate the time required for ColE2 binding to its receptor and translocation.

An ultrastructural study of sertoli cells in two geographically isolated populations of Aphanius dispar

1992 ◽  
Vol 50 (1) ◽  
pp. 548-549
Author(s):  
Taber A. Ba-Omar ◽  
Philip F. Prentis
Keyword(s):  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Freshwater Teleost ◽  
Isolated Populations ◽  
En Bloc ◽  
The North ◽  
Group A ◽  
Ultrathin Sections ◽  
Group B ◽  
Geographically Isolated

We have recently carried out a study of spermiogenic differentiation in two geographically isolated populations of Aphanius dispar (freshwater teleost), with a view to ascertaining variation at the ultrastructural level. The sampling areas were the Jebel Al Akhdar in the north (Group A) and the Dhofar region (Group B) in the south. Specimens from each group were collected, the testes removed, fixed in Karnovsky solution, post fixed in OsO, en bloc stained with uranyl acetate and then routinely processed to Agar 100 resin, semi and ultrathin sections were prepared for study.

Comparison of one-year prognosis of patients classified as chronic critical lower limb ischaemia according to TASC II or European consensus definition in the COPART cohort

VASA ◽  
2015 ◽  
Vol 44 (3) ◽  
pp. 0220-0228 ◽  
Author(s):  
Marion Vircoulon ◽  
Carine Boulon ◽  
Ileana Desormais ◽  
Philippe Lacroix ◽  
Victor Aboyans ◽  
...  
Keyword(s):  
Medical Treatment ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Medical Group ◽  
Consensus Definition ◽  
Transcutaneous Oxygen ◽  
European Consensus ◽  
Group A ◽  
One Year ◽  
Group B

Background: We compared one-year amputation and survival rates in patients fulfilling 1991 European consensus critical limb ischaemia (CLI) definition to those clas, sified as CLI by TASC II but not European consensus (EC) definition. Patients and methods: Patients were selected from the COPART cohort of hospitalized patients with peripheral occlusive arterial disease suffering from lower extremity rest pain or ulcer and who completed one-year follow-up. Ankle and toe systolic pressures and transcutaneous oxygen pressure were measured. The patients were classified into two groups: those who could benefit from revascularization and those who could not (medical group). Within these groups, patients were separated into those who had CLI according to the European consensus definition (EC + TASC II: group A if revascularization, group C if medical treatment) and those who had no CLI by the European definition but who had CLI according to the TASC II definition (TASC: group B if revascularization and D if medical treatment). Results: 471 patients were included in the study (236 in the surgical group, 235 in the medical group). There was no difference according to the CLI definition for survival or cardiovascular event-free survival. However, major amputations were more frequent in group A than in group B (25 vs 12 %, p = 0.046) and in group C than in group D (38 vs 20 %, p = 0.004). Conclusions: Major amputation is twice as frequent in patients with CLI according to the historical European consensus definition than in those classified to the TASC II definition but not the EC. Caution is required when comparing results of recent series to historical controls. The TASC II definition of CLI is too wide to compare patients from clinical trials so we suggest separating these patients into two different stages: permanent (TASC II but not EC definition) and critical ischaemia (TASC II and EC definition).

Absorbable suture material in carotid surgery

VASA ◽  
2015 ◽  
Vol 44 (6) ◽  
pp. 451-457 ◽  
Author(s):  
Vincenzo Gasbarro ◽  
Luca Traina ◽  
Francesco Mascoli ◽  
Vincenzo Coscia ◽  
Gianluca Buffone ◽  
...  
Keyword(s):  
Suture Material ◽  
Absorbable Suture ◽  
Paediatric Surgery ◽  
Carotid Surgery ◽  
Suture Materials ◽  
Absorbable Suture Material ◽  
Absorbable Sutures ◽  
Group A ◽  
Group B

Abstract. Background: Absorbable sutures are not generally accepted by most vascular surgeons for the fear of breakage of the suture line and the risk of aneurysmal formation, except in cases of paediatric surgery or in case of infections. Aim of this study is to provide evidence of safety and efficacy of the use of absorbable suture materials in carotid surgery. Patients and methods: In an 11 year period, 1126 patients (659 male [58.5 %], 467 female [41.5 %], median age 72) underwent carotid endarterectomy for carotid stenosis by either conventional with primary closure (cCEA) or eversion (eCEA) techniques. Patients were randomised into two groups according to the type of suture material used. In Group A, absorbable suture material (polyglycolic acid) was used and in Group B non-absorbable suture material (polypropylene) was used. Primary end-point was to compare severe restenosis and aneurysmal formation rates between the two groups of patients. For statistical analysis only cases with a minimum period of follow-up of 12 months were considered. Results: A total of 868 surgical procedures were considered for data analysis. Median follow-up was 6 years (range 1-10 years). The rate of postoperative complications was better for group A for both cCEA and eCEA procedures: 3.5 % and 2.0 % for group A, respectively, and 11.8 % and 12.9 % for group B, respectively. Conclusions: In carotid surgery, the use of absorbable suture material seems to be safe and effective and with a general lower complications rate compared to the use of non-absorbable materials.

Randomized trial of medical compression stockings versus two-layer short-stretch bandaging in the management of venous leg ulcers

Phlebologie ◽  
2009 ◽  
Vol 38 (04) ◽  
pp. 157-163 ◽  
Author(s):  
A. Franek ◽  
L. Brzezinska-Wcislo ◽  
E. Blaszczak ◽  
A. Polak ◽  
J. Taradaj
Keyword(s):  
Drug Therapy ◽  
Randomized Clinical Trials ◽  
Therapy Group ◽  
Long Term Results ◽  
Leg Ulcers ◽  
Compression Stockings ◽  
Venous Leg Ulcers ◽  
Group A ◽  
Group B ◽  
Medical Compression Stockings

SummaryA prospective randomized clinical trial was undertaken to compare a medical compression stockings with two-layer short-stretch bandaging in the management of venous leg ulcers. Study endpoints were number of completely healed wounds and the clinical parameters predicting the outcome. Patients, methods: Eighty patients with venous leg ulcers were included in this study, and ultimately allocated into two comparative groups. Group A consisted of 40 patients (25 women, 15 men). They were treated with the compression stockings (25–32 mmHg) and drug therapy. Group B consisted of 40 patients (22 women, 18 men). They were treated with the short-stretch bandages (30–40 mmHg) and drug therapy, administered identically as in group A. Results: Within two months the 15/40 (37.50%) patients in group A and 5/40 (12.50%) in group B were healed completely (p = 0.01). For patients with isolated superficial reflux, the healing rates at two months were 45.45% (10/22 healed) in group A and 18.18% (4/22 healed) in group B (p = 0.01). For patients with superficial plus deep reflux, the healing rates were 27.77% (5/18 healed) in group A and 5.55% (1/18 healed) in group B (p = 0.002). Comparison of relative change of the total surface area (61.55% in group A vs. 23.66% in group B), length (41.67% in group A vs. 27.99% in group B), width (46.16% in group A vs. 29.33% in group B), and volume (82.03% in group A vs. 40.01% in group B) demonstrated difference (p = 0.002 in all comparisons) in favour of group A. Conclusion: The medical compression stockings are extremely useful therapy in enhancement of venous leg ulcer healing (both for patients with superficial and for patients who had superficial plus deep reflux). Bandages are less effective (especially for patients with superficial plus deep reflux, where the efficiency compared to the stockings of applied compression appeared dramatically low). These findings require confirmation in other randomized clinical trials with long term results.

Hypercoagulable State in the Watanabe Heritable Hyperlipidemic Rabbit, an Animal Model for the Progression of Atherosclerosis

1989 ◽  
Vol 61 (01) ◽  
pp. 140-143 ◽  
Author(s):  
Yoshitaka Mori ◽  
Hideo Wada ◽  
Yutaka Nagano ◽  
Katsumi Deguch ◽  
Toru Kita ◽  
...  
Keyword(s):  
Vitamin K ◽  
Fibrinogen Level ◽  
Plasma Cholesterol ◽  
Age Groups ◽  
Clotting Factor ◽  
Clotting Factors ◽  
Group A ◽  
Hyperlipidemic Rabbit ◽  
Group B ◽  
Progression Of Atherosclerosis

SummaryBlood coagulation in a strain of rabbits designated as Watanabe heritable hyperlipidemic (WHHL) rabbits was examined. The activities of vitamin K-dependent clotting factors, contact factors and clotting factor VIII (F VIII) and the fibrinogen level were significantly higher in WHHL rabbits than in normolipidemic rabbits (all age groups). Values for vitamin Independent clotting factor were already higher at 2 months of age. Contact factors and fibrinogen levels increased age after 5 to 8 months. F VIII increased between 5 and 8 months and then decreased. At 2 months of age, WHHL rabbits were divided into two groups. Group A was fed standard rabbit chow and group B standard rabbit chow containing 1% probucol. Probucol prevented the progression of atherosclerosis in group B in the absence of a significant reduction in plasma cholesterol level. F VIII and fibrinogen levels were statistically decreased in all rabbits at all ages in group B (P<0.05). These differences in clotting factors between the two groups were most obvious at 8 months (P<0.02).We conclude that vitamin K-dependent clotting factors may increase with hyperlipemia and that increases in F VIII and fibrinogen may be closely related to the progression of throm- boatherosclerosis.

Factor II Related Antigen and Antithrombin III Levels as Indicators of Liver Failure in Consumption Coagulopathy

1982 ◽  
Vol 47 (03) ◽  
pp. 218-220 ◽  
Author(s):  
P Sié ◽  
E Letrenne ◽  
C Caranobe ◽  
M Genestal ◽  
B Cathala ◽  
...  
Keyword(s):  
Liver Failure ◽  
Antithrombin Iii ◽  
Coagulation Factors ◽  
Consumption Coagulopathy ◽  
Blood Coagulation Factors ◽  
Factor Ii ◽  
At Iii ◽  
Group A ◽  
Group B

SummaryIn order to detect impaired synthesis of blood coagulation factors associated to consumption coagulopathy, a simultaneous evaluation of factor II-related antigen (II rAg) and of antithrombin III (AT III) was carried out in 16 patients affected with severe defibrination. An in vitro preliminary study on plasma and serum demonstrated that the levels of II rAg and of AT III, assessed by the Laurell technique with Behring antisera, were not reduced by the coagulation process. The patients were, a posteriori, classified into two groups according to the absence (group A) or the presence (group B) of factors predisposing to liver failure such as metastasis, cirrhosis, and prolonged shock. II rAg and AT III levels are significantly correlated; they are in the normal range in group A but reduced in group B. Thus II rAg or AT III level determinations are useful markers in the detection of liver failure associated to the consumption phenomenon. These results also suggest that part of the decreased AT III levels reported in severe cases of disseminated intravascular coagulation may be the consequence of an associated liver failure.

Blood Viscosity and Platelet Aggregation in Male and Female Patients with Transient Ischaemic Attacks (TIA)

1979 ◽  
Author(s):  
G. Palareti ◽  
M. Poggi ◽  
G. Fortunato ◽  
S. Coccheri
Keyword(s):  
Platelet Aggregation ◽  
Blood Viscosity ◽  
Indirect Evidence ◽  
Vascular Lesions ◽  
Transient Ischaemic Attacks ◽  
Group A ◽  
Circulating Platelet Aggregates ◽  
Male Patients ◽  
Group B ◽  
Almost All

A series of 40 patients with TIA (25 males and 15 females) was thoroughly investigated by means of angiography and computerized tomography, and divided into a group (A) of 15 “sine materia”, and a group (B) of 25 with direct or indirect evidence of vascular occlusive or stenotic changes. Blood viscosity at 230 sec-1 37° was cp 4.2 ± 0.3 in the controls, cp 4.7 ± 0.7 in all patients (p < 0.05) cp 4.98 ± 0.7 in all male patients (p < 0.01 versus male controls), and cp 4.75 ± 0.8 in group B (p < 0.02). Haematocrit and Fibrinogen were also significantly increased in all male patients and in group B. Circulating platelet aggregates (CPA) were increased in 40% of the patients. Almost all patients with elevated CPA were males, with a slight prevalence in group B. Changes in blood viscosity parameters and in platelet aggregation in TIA patients were therefore related both to evidence of vascular lesions, and to sex, since they were found to prevail in male patients of both groups.

Study the Relationship Between Estrogen Hormone and Calcium in Normal Females Before and After Menopause in Baghdad / Iraq

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Sameerah Mustafa ◽  
Asal Tawfeeq ◽  
Hadeel Hasan
Keyword(s):  
Oral Contraceptive ◽  
Healthy Controls ◽  
Serum Samples ◽  
Oral Contraceptive Pills ◽  
Contraceptive Pills ◽  
Menopausal Women ◽  
Before And After ◽  
Group A ◽  
Group B ◽  
Age Range

This study involved the collection of (90) samples of women serum which included (30) serum samples collected from women before menopause (reproductive women) in the age range of (22-43) years and were considered as (group A- control). While, (group B) included (30) serum samples collected from women using oral contraceptive pills between the ages of (22-43) years old. Whereas, another (30) serum samples were collected from women after menopause between the ages of (43-54) years and were considered as (group C). All of the collected serum samples were subjected to a number of serological and chemical tests for the measurement of (E2, HDL, LDL and Ca). Then, the obtained data were statistical analyzed and results showed a significant decrease (p˂ 0.05) in (E2 ,Ca and HDL) levels in menopausal women compared to that of the normal healthy controls. While, there were non-significant decrease (p> 0.05) in (E2, Ca and HDL) levels in women taking oral contraceptive when compared to the normal healthy controls. On the other hand, a significant increase (p˂ 0.05) was recorded in LDL level in menopausal women compared to that of the normal healthy controls whereas, no-significant increase (p˃ 0.05) in the LDL level in women taking oral contraceptives when compared to the control women.

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