PRODUCTIVE AND BIOLOGICAL CHARACTERISTICS OF RUSSIAN MEAT MERINOS SHEEP WITH DIFFERENT LINEAR SELECTION

Line breeding is a difficult but effective zootechnical process in purebred sheep husbandry. Linear sheep consistently transmit their characteristics to offspring in order to increase and identify the most promising genotypes, characterized by high productivity and breeding efficiency, by detecting interline selection. The main purpose of the work was to identify the most suitable options for intra- and interline selection of the Russian meat merino breed. The article studies the early development of animals’ growth and physique, the high rates of animals, live weight in different age periods, slaughter and meat qualities. We established that young animals obtained by mating between the animal lines VK-40 and ME-50 were characterized by more proportional body shapes, better slaughter and meat qualities. The increase in live weight of lambs obtained by mating queens of the VK-40 line and rams of the ME-50 line (group III) was more intense than their peers from the intraline selection of the VK-40 line (I group) and of queens of the line AC- 30 with ME-50 rams (group II). The heaviest carcasses were in lambs obtained from the mating of queens of the VK-40 line and rams of the ME-50 line (13.26 kg), the weight of the carcass was greater, compared with the same indicator of the peers of groups I and II, respectively, by 7.7% and 4.0%, by internal fat mass – by 21.8% and 9.8%, by slaughter weight – by 8.3% and 4.3%

Serum prevalence to non-viral pathogens in wild felids of Southern Primorye, Russia

Serum prevalence to six different non-viral pathogens was estimated for big Russian cats (Amur tiger (Panthera tigris altaica) and the Far Eastern leopard (Panthera pardus orientalis)) in Southern Primorye, Russia (n = 26) in 2008–2016. Serum samples from smaller cats (Eurasian lynx (Lynx lynx) and Far Eastern wildcat (Prionailurus bengalensis euptilurus)) were also tested for these pathogens (n = 28) during the same period. Felids of Russian Southern Primorye showed serum prevalence to five out of six tested pathogens. Antibodies to Candida sp. and Trichinella sp. were found to be much more widespread in cats (47% and 42%) than antibodies to other tested pathogens (20% and less). Large cats demonstrated a higher serum prevalence to these pathogens than smaller ones. We did not detect animals seropositive to Coxiella burnetii

Synthetic peptides as a novel approach for detecting antibodies against sand fly saliva.

BACKGROUND: Hosts repeatedly bitten by sand flies develop antibodies against sand fly saliva and screening of these immunoglobulins can be employed to estimate the risk of Leishmania transmission, to indicate the feeding preferences of sand flies, or to evaluate the effectiveness of vector control campaigns. Previously, antibodies to sand fly saliva were detected using whole salivary gland homogenate (SGH) or recombinant proteins, both of which also have their disadvantages. This is the first study on sand flies where short peptides designed based on salivary antigens were successfully utilized for antibody screening. METHODOLOGY/PRINCIPAL FINDINGS: Specific IgG was studied in hosts naturally exposed to Phlebotomus orientalis, the main vector of Leishmania donovani in East Africa. Four peptides were designed by the commercial program EpiQuest-B, based on the sequences of the two most promising salivary antigens, yellow-related protein and ParSP25-like protein. Short amino acid peptides were synthesised and modified for ELISA experiments. Specific anti-P. orientalis IgG was detected in sera of dogs, goats, and sheep from Ethiopia. The peptide OR24 P2 was shown to be suitable for antibody screening; it correlated positively with SGH and its specificity and sensitivity were comparable or even better than that of previously published recombinant proteins. CONCLUSIONS/SIGNIFICANCE: OR24 P2, the peptide based on salivary antigen of P. orientalis, was shown to be a valuable tool for antibody screening of domestic animals naturally exposed to P. orientalis. We suggest the application of this promising methodology using species-specific short peptides to other sand fly-host combinations

Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

BACKGROUND: Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as TcI-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual's history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. METHODOLOGY/PRINCIPAL FINDINGS: We have applied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70%) of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001). Among northern chagasic sera 4/20 (20%) from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated here to be highly conserved across lineages and therefore not applicable to lineage-specific serology. CONCLUSIONS/SIGNIFICANCE: These results demonstrate the considerable potential for synthetic peptide serology to investigate the infection history of individuals, geographical and clinical associations of T. cruzi lineages

LDA analysis of swirling flow in a hydro turbine draft tube

The work reports on experimental study of flow and pressure pulsations in draft-tube of a laboratory air model of a Francis hydro-turbine operating over a broad range of regimes corresponding to different combinations of the runner rotation speed and flowrates. The velocity measurements using a computer-automated laser-Doppler anemometer and the pressure recording by wall-mounted acoustic sensors for a selection of operating conditions reveal different patterns of the swirling flow, with clearly identifiable regimes with the maximum flow pulsations at non-optimal operating conditions. The regimes with distinct precessing vortex cores show notable rearrangement of the velocity fields, accompanied by an increase in the amplitude of the pressure pulsations, as confirmed by the peaks of the spectra of pressure signals from wall-mounted microphones

Physical simulation of heat exchange between 6(10) kV voltage instrument transformer and its environment with natural convection and insolation

This study examines the results of thermal tests on a 6(10) kV digital combined current and voltage transformer conducted in an environmental chamber. This measuring instrument consists of current and voltage transformers, featuring a resistive divider, and is used for commercial and technical electric power accounting. Ambient temperatures and levels of insolation on the transformer surface were set for the environmental chamber, with simulation of voltage transformer functioning in normal and emergency modes. We determined the time needed for the thermodynamic system to move to steady heat exchange mode, and also the final temperatures in the lower resistors and on the surface of the voltage transformer insulation cover. The results of our study have been used in developing algorithms for self-diagnostics of the thermal state of a digital combined transformer