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Acta Microbiologica et Immunologica Hungarica
Authors: Emese Balogh, Tímea Mosolygó, Hilda Tiricz, Ágnes Szabó, Adrienn Karai, Fanni Kerekes, Dezső Virók, Éva Kondorosi and Katalin Burián

Even in asymptomatic cases of Chlamydia trachomatis infection, the aim of the antibiotic strategy is eradication of the pathogen so as to avoid the severe late sequelae, such as pelvic inflammatory disease, ectopic pregnancy, and tubal infertility. Although first-line antimicrobial agents have been demonstrated to be predominantly successful in the treatment of C. trachomatis infection, treatment failures have been observed in some cases. Rich source of antimicrobial peptides was recently discovered in Medicago species, which act in plants as differentiation factors of the endosymbiotic bacterium partner. Several of these symbiotic plant peptides have proved to be potent killers of various bacteria in vitro. We show here that 7 of 11 peptides tested exhibited antimicrobial activity against C. trachomatis D, and that the killing activity of these peptides is most likely due to their interaction with specific bacterial targets.

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Asymptomatic carriage of Staphylococcus aureus in healthy individuals has a high prevalence, especially in children and young adults. Nasal colonisation is a well-known risk factor for subsequent severe infection, or can be the source of transmission of this bacterium to other susceptible persons. In this study, we have surveyed the nasal carriage rate of students of the Semmelweis University, by screening 300 volunteers. We have determined the antibiotic sensitivity of the isolates by Etest, and their genetic relatedness by pulsed-fieled gel electrophoresis. The nasal carriage rate of S. aureus was found to be 29.3%, and that of MRSA only 0.67% (2/300). The isolates were generally sensitive to antibiotics, except for macrolides. We could observe a noticeably great genetic diversity, even among strains deriving from students of the same university group.

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Better vaccines and new therapeutic drugs could be a successful breakthrough against intracellular bacteria. M. tuberculosis ABC transporter ATPase (Rv0986) plays a role in mycobacterial virulence by inhibiting phagosome-lysosome fusion. Thus, it could be a potential vaccine candidate. C. pneumoniae another important intracellular bacterium possesses a protein named CpB0255, which is homologous with the mycobacterial Rv0986. The aim of this study was the cloning, over-expression and purification of CpB0255 ABC transporter ATPase protein to study its biological properties. The immunogenicity and protective effect of recombinant chlamydial ATPase protein combined with Alum adjuvant were investigated in mice. The immunization resulted in the reduction of the number of viable C. pneumoniae in the lungs after challenge. Our results confirm that chlamydial ATPase induces protective immunity in mice.

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The efficiency of three oxygen-vectors liquid paraffin, silicone oil and n-dodecane in the production of tyrosine phenol lyase (TPL) by Citrobacter freundii MTCC 2424 was evaluated at 4% (v/v) concentration. The liquid paraffin as oxygenvectors was found to exhibit a stimulatory effect on TPL synthesis. The liquid paraffin at 6% (v/v) resulted in 34% increase in the TPL synthesis accompanied by a 13% increase in the production of cell mass at a 10 L scale. This improvement in TPL and cell mass production in the presence of liquid paraffin can be related to the fact that liquid paraffin was capable of maintaining dissolved O2 concentration above 28% throughout the course of the fermentation. Maintenance of the dissolved O2 concentration above 28% could be viewed in terms of an adequate oxygen supply to the rapidly dividing cells of the bacterium, which in turn resulted in enhanced synthesis of TPL and cell mass.

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Abstract  

The thermogenic curves of the aerobic metabolism of the three strains of Bacillus thuringiensis B.t. A, B.t. B and B.t. C have been determined by using an LKB-2277 BioActivity Monitor. B.t. A was the host bacterium without foreign gene. B.t. B and B.t. C were constructed by transforming different foreign genes into the host B.t. A, respectively. B.t. B expressed erythromycin resistant gene, while B.t. C expressed both erythromycin resistant gene and tyrosinase gene. The heat flow rate of these strains is B.t. A> B.t. B >B.t. C. These results indicated that there is obvious interrelation between expression of foreign genes and heat flow rate of B.t. strains.

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The action of three kinds of the selenomorpholine compounds on a strain ofEscherichia coli was studied by microcalorimetry. Differences in their capacities to affect the metabolism of this bacterium were observed. The extent and duration of the effect on the metabolism as judged from the rate constant (k) of Escherichia coli (in log phase) varied with the different drugs. The kinetics show that selenomorpholine compounds had an effect on the metabolism process of Escherichia coli. The k of Escherichia coli in the presence of the drugs increased with the increasing concentrations of the drugs (C) at low concentration; but at high concentration, the rate constant decreased with the increasing concentrations of the drugs. The experimental results reveal that the sequence of antibiotic activity of selenomorpholines is: N-selenomorpholinemethyl succinimide and its hydrochloride>N-(α-selenomorpholinebenzyl) succinimide.

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The aim of this study was to investigate the change of Pu oxidation states due to interaction with aerobic bacteria and fungi at low pH under laboratory conditions. Microorganisms were isolated from samples collected from the low-level radioactive waste repository within the confines of Ignalina NPP. Abilities of the fungi (Absidia spinosa var spinosa Lendn. and Paecilomyces lilacinus Thom Samson) as well as Gram-positive bacteria (Bacillus mycoides and Micrococcus luteus) and Gram-negative bacterium I-m1 to transform the oxidation states of Pu under aerobic conditions were investigated. Oxidized and reduced Pu was tested using two radiochemical procedures. The amount of reduced and oxidized Pu was determined by measuring alpha activity after radiochemical separation. The results have shown that all bacteria and fungi can very slightly alter oxidation states of Pu due to their microbial activity. All the microorganisms tested demonstrate quite a fast process of Pu biosorption under the experimental conditions.

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Abstract

There are numerous biological agents including bacteria such as Brucella suis, B. abortus, Francisella tularensis, Burkholderia mallei, Coxiella burnetii, Yersina pestis, Bacillus anthracis and Chlamydia psittaci, viruses such as Variola major and V. minor, Flavivirus and Hantavirus, and toxins such as Botulinum toxin produced by the bacterium Clostridium botulinum, Staphylococcus enterotoxin B and Trichothecene mycotoxin reported to have potential to cause illness via water consumption. In the recent years, biological threat prevention for urban water supply systems has been of special interest worldwide, thus, protection against biological agents requires adequate knowledge, available water treatment technologies and preparedness. In this review, the history of biological threat via public water supply, as well as selected early detection methods, prevention strategies and risk assessment models are detailed.

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Selection
Authors: J. Randerson, J. Moreau, T. Rigaud and Laurence D. Hurst

Within isopod crustaceans, the vertically transmitted bacteria Wolbachia induces either cytoplasmic incompatibility (CI) or feminization of male hosts. One of the challenges is to understand the distribution of the different manipulations between species. The invasion conditions for feminizers are much broader than for CI inducers and so the former is expected to be the more common, all else being equal. Here we ask whether prior infection with one type predisposes or inhibits the spread of a strain causing the opposite manipulation. Were this so, historical accident might have to be evoked to explain which species is affected by which type. We consider two possibilities. First, the appearance of a new mutant bacterium capable of both manipulations. Second, the appearance, via horizontal transfer, of a new bacterium capable of only one manipulation. In a mutational model, invasion of CI into a population with a feminizer is trivial, as is the reverse. This provides the first mechanism for trivial invasion of CI, but its biological relevance is unclear. In the horizontal transfer model, replacement of one type by another can occur if infection is initially into an uninfected lineage. However, under these circumstances neither form is likely to spread. If the initial horizontal transfer event is into an infected lineage, then under the most realistic circumstances, the prior existence of one form has little effect on the conditions for spread of the other, but may marginally inhibit or promote spread. If spread does occur, stable duel infection is the most common equilibrium condition. We suggest reasons as to why this has yet to be observed.

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-oxidizing bacterium isolated from an underground crude-oil storage cavity. Int. J. Syst. Evol. Microbiol. 54 , 2297–2300 (2004). Watanabe K. Sulfuricurvum kujiense gen. nov., sp. nov., a

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