Temperature influences the expression of fimbriae and flagella in <Emphasis Type="Italic">Hafnia alvei</Emphasis> strains: an immunofluorescence study

Hafnia alvei, a Gram negative bacillus related to the Enterobacteriaceae family, is considered an opportunistic pathogen of several animal species and humans. In this communication, we describe fimbrial-like structures from different strains of H. alvei that cannot be easily ascribed to any of the previously reported fimbrial types in this species (type I or type III). Polymerase chain reaction (PCR) and immunofluorescence assays were carried out to study fimbriae and flagella in H. alvei strains isolated from different sources. No correlation between the results obtained by PCR and those obtained by phenotypic methods were found, and the antibodies used gave cross or different recognition patterns of the surface structures present in these strains. We report as well that strain and growth temperature influence fimbriation and expression of flagella in human and animal isolates of H. alvei. This study also indicates that the absence of fimbriae have a significant positive influence on the initial adhesion of H. alvei to human epithelial cells.     

Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major

ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an appropriate molecular template for the construction of an efficient anti-infective agent.     

Status of the reproductive system of bony fish from the Teterev River and the Kiev Reservoir 20 years after the Chernobyl accident

The status of the reproductive system is investigated in five species of Teleostei from the Teterev River and the Kiev Reservoir (Ukraine), descendants of F₄2–F₇ generations of fish exposed to radiation from the accident at the Chernobyl nuclear power plant. Twenty years after the accident, a wide range of morphofuinctional anomalies of this system is present in fish. The most significant of them are: asymmetry and anomalous morphology of gonads, proliferation of connective tissue—sterilization, mass destruction of follicular and sex cells of various developmental stages, and hermaphroditism. Among the investigated species, disturbances of reproductive glands were preset to the highest extent in pike Esox lucius and crucian carp Carassius carassius. In the series of investigated generations the maximum frequency of occurrence of gonad anomalies was noted in F₄ and F₅, due to prolonged mutagenesis (Dubinin, 1986).     

Determination of the structural integrity of DNA from pathogenic enterobacteria

Among the enterobacterial strains under study, more organisms in the stationary phase of growth have been found to have nicks in their DNA than those in the exponential phase. Bacteria less sensitive to ultraviolet irradiation have the least number of nicks in each phase of growth. The number of nicks in different strains belonging to the serovar is sufficiently stable. Virulent and avirulent forms show no difference in this characteristic.     

Zur Taxonomie von Rhodopseudomonas palustris

Zusammenfassung Eine Reihe von Rhodopseudomonas palustris-Stämmen aus verschiedenen Herkünften wurden vergleichend unter Verwendung folgender Merkmale untersucht: Substratverwertung, in vivo-Absorptionsspektrum und Serologie der O-Antigene. Die gegen 2 Stämme gerichteten Antiseren zeigen hohe Spezifität. Die Verwendbarkeit der serologischen Kreuzreaktion für taxonomische Untersuchungen bei photosynthetischen Bakterien wird diskutiert.

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On the taxonomy of Rhodopseudomonas palustris

Summary Strains of Rhodopseudomonas palustris isolated from different habitats were compared with respect to their taxonomic features. All strains grew very well on formiate, acetate, propionate, butyrate, aspartate, inositol, ethanol, fructose, and p-amino-benzoate, respectively, as single carbon source. Most of the strains were able to use benzoic acid or glucose, too. But alanine was not found to be a good substrate. The maxima of the bacteriochlorophyll in-vivo-absorption spectra were estimated to be 376, 589, 802–805, and 858–875 nm. The shift of the infrared peak in the different strains is loosely correlated with the change of the carotenoid in vivo spectrum, the maxima of which were measured to be 470–480 nm (shoulder) 495–505 nm, and 520–545 nm (shoulder). Antisera were prepared against the strains 1e5 and 11/1. It was demonstrated that these antisera were directed against the lipopolysaccharides (O-antigen) of these bacteria. The antigen of 1e5 does not cross react with the antigen of 11/1. Strain 1e5 is the only one of 17 strains tested which is sensitive to the bacteriophage Rp1. The antigen of this strain cross reacted only with the antigen of strain K1. In contrast, the antigen of strain 11/1 cross reacted in some degree with most of the tested strains of Rps. palustris. No or very weak cross reaction was observed between the antigens of Rps. palustris (1e5, 11/1) and Rps. capsulata, Rps. spheroides, or R. rubrum, respectively. In contrast to 11/1 only heat-killed cells of strain 1e5 were agglutinated by anti-1e5.

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Im Text verwendete Abkürzungen LPS Lipopolysaccharid - R Rhodospirillum - Rps. Rhodopseudomonas - i.m. intramuskulär - s.c. subcutan - i.v. intravenös