Removing endosymbiotic Wolbachia specifically decreases lifespan of females and competitiveness in a laboratory strain of Drosophila melanogaster

To understand specific symbiotic relationships ensuring stable existing of the bacterium Wolbachia in laboratory strains of Drosophila melanogaster, the imago lifespan and senescence rate, as well as competitiveness, have been evaluated as components of fitness in females from the following laboratory strains: (1) inbred strain 95 infected with Wolbachia; (2) two uninfected strains obtained by tetracycline treatment that were genetically similar to strain 95; and (3) two control, uninfected, wild-type laboratory strains that were used to assess the possible effects of the antibiotic on the studied characters in the absence of Wolbachia. The results have shown that infected females have longer lifespan and competitiveness than females with the same genotype uninfected with Wolbachia. The increase in the senescence and mortality rates with age was also slower in infected females. It is noteworthy that tetracycline does not affect the lifespan of females from the two control, uninfected, wild-type strains. Therefore, the antibiotic is not the cause of the positive changes in fitness that were observed in infected females. The obtained results are the first direct evidence that the relationship s in the Wolbachia-D melanogaster symbiotic system are mutualistic rather than parasitic, at least in micropopulations adapted to laboratory conditions.     

Convective tissue movements play a major role in avian endocardial morphogenesis

Endocardial cells play a critical role in cardiac development and function, forming the innermost layer of the early (tubular) heart, separated from the myocardium by extracellular matrix (ECM). However, knowledge is limited regarding the interactions of cardiac progenitors and surrounding ECM during dramatic tissue rearrangements and concomitant cellular repositioning events that underlie endocardial morphogenesis. By analyzing the movements of immunolabeled ECM components (fibronectin, fibrillin-2) and TIE1 positive endocardial progenitors in time-lapse recordings of quail embryonic development, we demonstrate that the transformation of the primary heart field within the anterior lateral plate mesoderm (LPM) into a tubular heart involves the precise co-movement of primordial endocardial cells with the surrounding ECM. Thus, the ECM of the tubular heart contains filaments that were associated with the anterior LPM at earlier developmental stages. Moreover, endocardial cells exhibit surprisingly little directed active motility, that is, sustained directed movements relative to the surrounding ECM microenvironment. These findings point to the importance of large-scale tissue movements that convect cells to the appropriate positions during cardiac organogenesis.     

Creation of thermostable polypeptide cassettes for amino acid balancing in farm animal rations

The study of the poultry needs in basic nutrients allowed the development of a scheme for obtaining feed polypeptides (“polypeptide cassettes”) enriched with L-amino acids, which are necessary for the metabolism of birds. The amino acid and nucleotide profiles of about 500 bioinformation sequences of thermostable plant proteins and archaea were studied, on the basis of which candidate sequences were selected. In silico, the amino acid and domain composition of the thermostable polypeptides has been optimized. A library of genetically engineered constructs encoding optimized polypeptides with the necessary composition of L-amino acids irreplaceable for poultry has been created. Primary E. coli producer strains were obtained, and the expression and thermostability of the target polypeptides were studied.     

Ultrastructural Study of Relationships between Germinal Bodies and Mitochondria in Apostichopus japonicus (Echinodermata: Holothuroidea) and Pleuronectes asper (Teleostei: Pleuronectidae)

The relationships between germinal bodies and mitochondria were studied in the holothurian Apostichopus japonicus and the flounder Pleuronectes asper using TEM. In the gonial cells of both species the mitochondria are arranged around germinal bodies and are in contact with the latter. A gradual disappearance of the outer membrane is found in the mitochondria that interact with the germinal substance. Later on, dispersion of the globules of the mitochondrial matrix containing mitochondrial cristae occurs. It is supposed that the substance of the mitochondrial matrix takes part in the development and functioning of the germinal plasm in both invertebrates and vertebrates.     

The characteristics of the accumulation and elimination of organophosphorus compounds in rats

Peculiarities of accumulation and excretion of different phosphor-organic pesticides from stomach wall at peroral introduction in LD50 dose. The data on dependence of pesticide LD50 on the rate of accumulation is stomach wall, the time of their biological lifetime, the direction of metabolism, and content of intact pesticides in liver tissues have been presented.     

Monitoring of microbial degraders in manned space stations

Samples of microorganisms from the surface of constructions of Mir Space Station (Mir SS) were taken and examined after 13 years of operation. The following microorganisms were isolated and identified: 12 fungal species belonging to the genera Penicillium, Aspergillus, Cladosporium, and Aureobasidium; 3 yeast species belonging to the genera Debaryomyces, Candida, and Rhodotorula; and 4 bacterial species belonging to the genera Bacillus, Myxococcus, and Rhodococcus. The predominant species in all samples was Penicillium chrisogenum. It was shown that the fungi isolated could damage polymers and induce corrosion of aluminum-magnesium alloys. We commenced a study of microbial degraders on constructions of the Russian section of the International Space Station (RS ISS). Twenty-six species of fungi, bacteria, yeasts, and actinomycetes, known as active biodegraders, were identified in three sample sets taken at intervals. We founded a collection of microorganisms surviving throughout space flights. This collection can be used to test spacecraft production materials, in order to determine their resistance to biodegradation.