scholarly journals Mutation of a degS Homologue in Enterobacter cloacae Decreases Colonization and Biological Control of Damping-Off on Cucumber

2011 ◽  
Vol 101 (2) ◽  
pp. 271-280 ◽  
Author(s):  
Daniel P. Roberts ◽  
Scott M. Lohrke ◽  
Laurie McKenna ◽  
Dilip K. Lakshman ◽  
Hyesuk Kong ◽  
...  
Keyword(s):  
Stress Response ◽  
Enterobacter Cloacae ◽  
Pythium Ultimum ◽  
Damping Off ◽  
E Coli ◽  
Transposon Insertion ◽  
Acidic Conditions ◽  
And Control ◽  
First Time ◽  
Reducing Stress

We have been using mutagenesis to determine how biocontrol bacteria such as Enterobacter cloacae 501R3 deal with complex nutritional environments found in association with plants. E. cloacae C10, a mutant of 501R3 with a transposon insertion in degS, was diminished in growth on synthetic cucumber root exudate (SRE), colonization of cucumber seed and roots, and control of damping-off of cucumber caused by Pythium ultimum. DegS, a periplasmic serine protease in the closely related bacterium Escherichia coli K12, is required for the RpoE-mediated stress response. C10 containing wild-type degS from 501R3 or from E. coli K12 on pBeloBAC11 was significantly increased in growth on SRE, colonization of cucumber roots, and control of P. ultimum relative to C10 containing pBeloBAC11 alone. C10 and 501R3 were similar in sensitivity to acidic conditions, plant-derived phenolic compounds, oxidative stress caused by hydrogen peroxide, dessication, and high osmoticum; stress conditions potentially associated with plants. This study demonstrates a role for degS in the spermosphere and rhizosphere during colonization and disease control by Enterobacter cloacae. This study implicates, for the first time, the involvement of DegS and, by extension, the RpoE-mediated stress response, in reducing stress on E. cloacae resulting from the complex nutritional environments in the spermosphere and rhizosphere.

scholarly journals Induction and control of the autolytic system of Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 26-34
Author(s):  
M Leduc ◽  
R Kasra ◽  
J van Heijenoort
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Acid Synthesis ◽  
Induction Method ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Carbonyl Cyanide ◽  
And Control ◽  
First Time ◽  
Induced Autolysis

Various methods of inducing autolysis of Escherichia coli cells were investigated, some being described here for the first time. For the autolysis of growing cells only induction methods interfering with the biosynthesis of peptidoglycan were taken into consideration, whereas with harvested cells autolysis was induced by rapid osmotic or EDTA shock treatments. The highest rates of autolysis were observed after induction by moenomycin, EDTA, or cephaloridine. The different autolyses examined shared certain common properties. In particular, regardless of the induction method used, more or less extensive peptidoglycan degradation was observed, and 10(-2) M Mg2+ efficiently inhibited the autolytic process. However, for other properties a distinction was made between methods used for growing cells and those used for harvested cells. Autolysis of growing cells required RNA, protein, and fatty acid synthesis. No such requirements were observed with shock-induced autolysis performed with harvested cells. Thus, the effects of Mg2+, rifampicin, chloramphenicol, and cerulenin clearly suggest that distinct factors are involved in the control of the autolytic system of E. Coli. Uncoupling agents such as sodium azide, 2,4-dinitrophenol, and carbonyl-cyanide-m-chlorophenyl hydrazone used at their usual inhibiting concentration had no effect on the cephaloridine or shock-induced autolysis.

scholarly journals Mutation of rpiA in Enterobacter cloacae Decreases Seed and Root Colonization and Biocontrol of Damping-Off Caused by Pythium ultimum on Cucumber

2002 ◽  
Vol 15 (8) ◽  
pp. 817-825 ◽  
Author(s):  
Scott M. Lohrke ◽  
Pierre D. Dery ◽  
Wei Li ◽  
Ralph Reedy ◽  
Donald Y. Kobayashi ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Sequence Similarity ◽  
Enterobacter Cloacae ◽  
Pythium Ultimum ◽  
Pentose Phosphate ◽  
Disease Suppression ◽  
Amino Acid Sequence Similarity ◽  
Damping Off ◽  
Isomerase Activity ◽  
Key Enzyme

Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum. Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3. Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days, while populations of strain 501R3 remained at substantial levels throughout all experiments. Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase. In Escherichia coli, RpiA catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate and is a key enzyme in the pentose phosphate pathway. Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant. Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3. Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae.

scholarly journals DEGR-factor Xa blocks disseminated intravascular coagulation initiated by Escherichia coli without preventing shock or organ damage

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 364-368 ◽  
Author(s):  
FB Jr Taylor ◽  
AC Chang ◽  
GT Peer ◽  
T Mather ◽  
K Blick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Injury ◽  
Factor Xa ◽  
Organ Damage ◽  
Lethal Outcome ◽  
Chloromethyl Ketone ◽  
E Coli ◽  
And Control ◽  
First Time

One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1- naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

scholarly journals DEGR-factor Xa blocks disseminated intravascular coagulation initiated by Escherichia coli without preventing shock or organ damage

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 364-368 ◽  
Author(s):  
FB Jr Taylor ◽  
AC Chang ◽  
GT Peer ◽  
T Mather ◽  
K Blick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Injury ◽  
Factor Xa ◽  
Organ Damage ◽  
Lethal Outcome ◽  
Chloromethyl Ketone ◽  
E Coli ◽  
And Control ◽  
First Time

Abstract One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1- naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

scholarly journals Sterol 14α-demethylase activity in Streptomyces coelicolor A3(2) is associated with an unusual member of the CYP51 gene family

2002 ◽  
Vol 364 (2) ◽  
pp. 555-562 ◽  
Author(s):  
David C. LAMB ◽  
Kay FOWLER ◽  
Tobias KIESER ◽  
Nigel MANNING ◽  
Larissa M. PODUST ◽  
...  
Keyword(s):  
Streptomyces Coelicolor ◽  
Open Reading Frame ◽  
Reading Frame ◽  
E Coli ◽  
Transposon Insertion ◽  
Cell Extracts ◽  
C Terminus ◽  
Demethylase Activity ◽  
First Time

The annotation of the genome sequence of Streptomyces coelicolor A3(2) revealed a cytochrome P450 (CYP) resembling various sterol 14α-demethylases (CYP51). The putative CYP open reading frame (SC7E4.20) was cloned with a tetrahistidine tag appended to the C-terminus and expressed in Escherichia coli. Protein purified to electrophoretic homogeneity was observed to bind the 14-methylated sterols lanosterol and 24-methylene-24,25-dihydrolanosterol (24-MDL). Reconstitution experiments with E. coli reductase partners confirmed activity in 14α-demethylation for 24-MDL, but not lanosterol. An S. coelicolor A3(2) mutant containing a transposon insertion in the CYP51 gene, which will abolish synthesis of the functional haemoprotein, was isolated as a viable strain, the first time a CYP51 has been identified as non-essential. The role of this CYP in bacteria is intriguing. No sterol product was detected in non-saponifiable cell extracts of the parent S. coelicolor A3(2) strain or of the mutant. S. coelicolor A3(2) CYP51 contains very few of the conserved CYP51 residues and, even though it can catalyse 14α-demethylation, it probably has another function in Streptomyces. We propose that it is a member of a new CYP51 subfamily.

scholarly journals Progress in the development of vaccines and strategies of their application in the control of infectious diseases of swine

2020 ◽  
Vol 76 (03) ◽  
pp. 6384-2020
Author(s):  
ZYGMUNT PEJSAK ◽  
MARIAN TRUSZCZYŃSKI ◽  
HANNA LUTNICKA
Keyword(s):  
Infectious Diseases ◽  
Recombinant Vaccine ◽  
Genetic Changes ◽  
Live Vaccines ◽  
E Coli ◽  
Inactivated Vaccines ◽  
Baculovirus System ◽  
And Control ◽  
First Time ◽  
Oedema Disease

Data are presented concerning vaccines used in the prophylaxis and control of some viral and bacterial infectious diseases of swine, particularly against: MPS, PRRS, PMWS CSF, AD, SI, E. coli, Cl. perfringens type C and A and oedema disease. The lower efficacy in immunization of inactivated vaccines is stressed. However in case of live vaccines against PRRS this is not always the case since also live attenuated vaccines deliver unsatisfactory results of immunization. This is explained by frequently occurring genetic changes in the genome of the field PRRSV strains in comparison with the strain or strains being in the vaccine. Vaccines against PMWS are characterized, underlining high efficacy of the vaccines in the Baculovirus system. After withdrawing from field use against CSF the vaccines Lapest and Cellpest a recombinant vaccine against CSF was introduced for control of this disease. A recombinant vaccine against AD of swine is mentioned, which was successfully used in eradication program in Europe. Of high practical value is mentioned a vaccine against SI containing subptypes H1N1, H3N2 and H1N1. Referring to vaccines against viral diseases of swine marker vaccines were mentioned enabling differentiation of animals infected from vaccinated (DIVA strategy). At the beginning of the XXI century several new and effective vaccines were developed, produced and used against diarrheal diseases of different etiology and for the first time against oedema disease. The role of strategy of vaccination depending on the characteristic of the infectious disease, the vaccine and the production system of swine is present.

scholarly journals Differential Inactivation of Seed Exudate Stimulation of Pythium ultimum Sporangium Germination by Enterobacter cloacae Influences Biological Control Efficacy on Different Plant Species

2003 ◽  
Vol 69 (2) ◽  
pp. 1114-1120 ◽  
Author(s):  
Koji Kageyama ◽  
Eric B. Nelson
Keyword(s):  
Biological Control ◽  
Plant Species ◽  
Enterobacter Cloacae ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Control Efficacy ◽  
Stimulatory Activity ◽  
Seed Exudate ◽  
Pea Seeds ◽  
Stimulation Of

ABSTRACT This study was initiated to understand whether differential biological control efficacy of Enterobacter cloacae on various plant species is due to differences in the ability of E. cloacae to inactivate the stimulatory activity of seed exudates to Pythium ultimum sporangium germination. In biological control assays, E. cloacae was effective in controlling Pythium damping-off when placed on the seeds of carrot, cotton, cucumber, lettuce, radish, tomato, and wheat but failed to protect corn and pea from damping-off. Seeds from plants such as corn and pea had high rates of exudation, whereas cotton and cucumber seeds had much lower rates of exudation. Patterns of seed exudation and the release of P. ultimum sporangium germination stimulants varied among the plants tested. Seed exudates of plants such as carrot, corn, lettuce, pea, radish, and wheat were generally more stimulatory to P. ultimum than were the exudates of cotton, cucumber, sunflower, and tomato. However, this was not directly related to the ability of E. cloacae to inactivate the stimulatory activity of the exudate and reduce P. ultimum sporangium germination. In the spermosphere, E. cloacae readily reduced the stimulatory activity of seed exudates from all plant species except corn and pea. Our data have shown that the inability of E. cloacae to protect corn and pea seeds from Pythium damping-off is directly related to its ability to inactivate the stimulatory activity of seed exudates. On all other plants tested, E. cloacae was effective in suppressing damping-off and inactivating the stimulatory activity of seed exudates.

Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
Klebsiella Oxytoca ◽  
Enterobacter Aerogenes ◽  
Enterobacter Cloacae ◽  
Proteus Vulgaris ◽  
Providencia Rettgeri ◽  
E Coli

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.

The effect of type of water supply on water quality in a developing community in South Africa

1997 ◽  
Vol 35 (11-12) ◽  
pp. 35-40 ◽  
Author(s):  
B. Genthe ◽  
N. Strauss ◽  
J. Seager ◽  
C. Vundule ◽  
F. Maforah ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Supply ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
E Coli ◽  
Guideline Values ◽  
Developing Communities ◽  
Quality Guideline ◽  
And Control ◽  
The Relationship

Efforts to provide water to developing communities in South Africa have resulted in various types of water supplies being used. This study examined the relationship between the type of water supply and the quality of water used. Source (communal taps, private outdoor and indoor taps) and point-of-use water samples were examined for heterotrophic plate counts (HPC), total and faecal coliforms, E. coli, and coliphages. Ten percent of samples were also analysed for enteric viruses, Giardia and Cryptosporidium. Approximately 320 households were included in a case-control study. In addition, a cross-sectional study was conducted. Both studies examined the relationship between different types of water facilities and diarrhoea among pre-school children. The source water was of good microbial quality, but water quality was found to have deteriorated significantly after handling and storage in both case and control households, exceeding drinking water quality guideline values by 1-6 orders of magnitude. Coliphage counts were low for all water samples tested. Enteric viruses and Cryptosporidium oocysts were not detected. Giardia cysts were detected on one occasion in case and control in-house samples. Comparisons of whether in-house water, after handling and storage, complied with water quality guideline values demonstrated households using communal taps to have significantly poorer quality than households using private outdoor or indoor taps for HPC and E. coli (χ2 = 14.9, P = 0.001; χ2 = 6.6, P = 0.04 respectively). A similar trend (although not statistically significant) was observed for the other microbial indicators. The cross-sectional study demonstrated an apparent decrease in health risk associated with private outdoor taps in comparison to communal taps. This study suggests that a private outdoor tap is the minimum level of water supply in order to ensure the supply of safe water to developing communities.

The Effects of Corporate Ownership on Public Accountants' Professionalism and Ethics

2002 ◽  
Vol 16 (2) ◽  
pp. 109-124 ◽  
Author(s):  
William E. Shafer ◽  
D. Jordan Lowe ◽  
Timothy J. Fogarty
Keyword(s):  
Current Trend ◽  
Auditor Independence ◽  
Corporate Ownership ◽  
Negative Effects ◽  
Public Accounting ◽  
Corporate Acquisitions ◽  
Accounting Professionals ◽  
Research Questions ◽  
And Control ◽  
First Time

The current trend toward corporate acquisitions of CPA firms poses potential threats to the autonomy and ethical standards of public accounting professionals. This recent consolidation movement suggests that for the first time a significant number of public accounting professionals are subject to the supervision and control of nonprofessionals. In addition to acknowledging the potential threats to auditor independence and objectivity, this paper suggests that these new organizational arrangements for the provision of public accounting services have other negative effects on professionalism and ethics such as desensitizing CPAs to traditional professional values, and subverting professional institutions to the goals of corporate employers. This paper develops a framework that identifies several specific research questions related to the effects of corporate ownership on professionalism and ethics in public accounting.

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