A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Alcohol dehydrogenase and adaptation to ethanol in Drosophila

The subject of this research is activity and allozyme spectra of alcohol dehydrogenase (ADH), and survival of mutant strains of Drosophila kept in standard nutrient medium with added ethanol. In all experiments the ADH of flies revealed greater affinity to isopropanol than ethanol. The mutant strains considerably differed from one another and from the wild type of flies in the level of enzyme activity, which may be connected with genotypic properties in the mutants studied. The ADH variability in mutant strains seems to be caused by different alleles of the structural ADH gene, which was established as a result of investigation of activity, electrophoretic mobility and thermostability of corresponding allozymes. As follows from experiments on the genotypical structure of populations in the conditions of fly selection in the medium containing ethanol (10%), the adaptation of flies to exogenous ethanol takes place via mechanisms of allele control of the ADH activity. Phenotypical manifestation of the ADH locus and its effect on the resistance of Drosophila to alcohol are supposed to depend on complex gene interactions determined by the genotype as a whole.     

<Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> inhibits <Emphasis Type="Italic">in-vitro Candida</Emphasis> biofilm development

Background  

Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development.     

Determination of quantitative parameters of Escherichia coli phagocytosis by mouse peritoneal macrophages

The fluorometric method was used to study guantitative parameters of phagocytosis of fluorescein-labeled Escherichia coli cells by mouse peritoneal macrophages. E. coli cells were conjugated with fluoresceinisothiocyanate (FITC) and then incubated with macrophages. At the end of the assay phagocytosis was arrested with a lysing solution (0.5% Triton X-100 in 0.01 M phosphate-buffered 0.15 M saline, pH 7.4). Trypan blue at a concentration of 0.04% was used as a quenching agent to differentiate between attachment and ingestion of E. coli cells. The time course analysis within this method showed that phagocytosis of E. coli cells was temperature and opsonin dependent. The number of E. coli cells ingested by macrophages increased rapidly during the initial 60 min of incubation at 37 degrees C. E. coli cells required opsonization with 5% native serum to achieve their optimal uptake. The uptake of nonopsonized bacteria by macrophages was significantly lower that that of opsonized ones (P < 0.05). It was demonstrated that sodium azide inhibited phagocytosis of E. coli cells by mouse peritoneal macrophages in a dose-dependent manner.     

Molecular determinants of caste differentiation in the highly eusocial honeybee <Emphasis Type="Italic">Apis mellifera</Emphasis>

Background  

In honeybees, differential feeding of female larvae promotes the occurrence of two different phenotypes, a queen and a worker, from identical genotypes, through incremental alterations, which affect general growth, and character state alterations that result in the presence or absence of specific structures. Although previous studies revealed a link between incremental alterations and differential expression of physiometabolic genes, the molecular changes accompanying character state alterations remain unknown.     

Mitochondrial haplotype diversity in the tortoise species <Emphasis Type="Italic">Testudo graeca</Emphasis> from North Africa and the Middle East

Background  

To help conservation programs of the endangered spur-thighed tortoise and to gain better insight into its systematics, genetic variation and evolution in the tortoise species Testudo graeca (Testudines: Testudinidae) was investigated by sequence analysis of a 394-nucleotide fragment of the mitochondrial 12S rRNA gene for 158 tortoise specimens belonging to the subspecies Testudo graeca graeca, Testudo graeca ibera, Testudo graeca terrestris, and a newly recognized subspecies Testudo graeca whitei. A 411-nucleotide fragment of the mitochondrial D-loop was additionally sequenced for a subset of 22 T. graeca, chosen because of their 12S gene haplotype and/or geographical origin.