Genetika

Based on the specific aptamer-functionalized magnetic beads and the hybrid chain reaction (HCR), a rapid detection method for Bacillus cereus was established. B. cereus competes with carboxylfluorescein-labeled cDNA (FAM-cDNA) to bind to biotin-labeled aptamer fixed on streptavidin magnetic beads. After magnetic separation, the released FAM-cDNA was used as an initiator to trigger HCR amplification, significantly enhancing the fluorescence signal. In the absence of B. cereus, the initiator binds to the aptamer, generating only a weak fluorescent signal. More importantly, graphene oxide (GO) can quench the fluorescence of unreacted FAM-cDNA, achieving a more accurate detection effect and thus enabling the detection of B. cereus at lower concentrations. This method has good specificity and can detect B. cereus as low as 5.4×101 CFU/mL. A linear response was observed across the concentration range of 5.4×105 CFU/mL-5.4×101 CFU/mL. The feasibility of this method was verified by detecting B. cereus in artificially contaminated milk samples.

Bacillus cereus is a common Gram-positive bacterium that poses a significant threat to food safety due to its environmental adaptability, spore-forming ability, and production of harmful toxins. Traditional detection methods for B. cereus are time-consuming and inaccurate. This study aimed to develop a rapid enrichment medium for B. cereus to improve detection efficiency. Five B. cereus strains and five non-B. cereus strains were used. The TSB medium was selected as the basic medium as it supported the best growth and spore germination of B. cereus among the tested media. Magnesium sulfate and inosine were identified as the most effective promoters for the growth of vegetative cells and spore germination respectively, while glycine and sodium nitrite were chosen as suitable inhibitors against non-B. cereus bacteria. Through orthogonal experiments, the optimal formulation of the rapid enrichment medium (BC-TSB) was determined. BC-TSB effectively inhibited the growth of non-target bacteria and significantly promoted the growth and spore germination of B. cereus compared to the TSB basic medium. It also efficiently facilitated the recovery of thermally injured B. cereus cells, with a 6 h recovery rate of 87%-shortening the incubation time required by traditional method from 48 h to 6 h. In the detection of artificially contaminated dairy samples, BC-TSB could effectively pre-enrich B. cereus, achieving a 100% detection rate in UHT milk, modified milk, and pasteurized milk using both traditional and PMAxx-qPCR methods. Overall, the developed BC-TSB medium has great potential for the rapid and accurate detection of B. cereus in food, which can help enhance food safety monitoring.

The rapid detection of pathogenic bacteria is important for the global public health field. Existing detection technologies are generally limited by log efficiency, high costs, and susceptibility to contamination. Advanced detection methods, such as surface plasmon resonance (SPR), have been proposed to break these limitations, with the advantages of fast detection speed and high sensitivity. SPR operates on the principle of attenuated total internal reflection at a metal–dielectric interface. This technique exploits the resonant absorption of incident photons by surface plasmons, facilitating the detection of tiny variations in the local refractive index by tracking the resonance condition change. This review provides a comprehensive overview of the development in the detection of foodborne pathogens using SPR technology, including a detailed discussion of the working principles of SPR, related instrumentation, and various detection methods. Specifically, this review focuses on a discussion of different SPR detection methods in terms of assembly processes, detection specificity, sensitivity, and detection limits in SPR biosensors, aiming to provide the readers with a fundamental knowledge of SPR.

This study aimed to partition the genomic variance of carcass weight (CW), marbling score (MS), rib-eye area (REA), and back fat thickness (BFT) traits in Angus beef cattle into components associated with minor allele frequency (MAF) bins, functional annotation classes, and chromosomes. The dataset included 6,511,978 (6.5 million) imputed whole-genome sequence (WGS) SNPs from 13,241 Angus beef cattle. Genomic partitioning was performed using a multi-component mixed linear model analysis, modeling random effects with multiple genomic relationship matrices (GRMs), either simultaneously (joint analysis) or separately (separate analysis). The estimated heritability (h 2) for CW, MS, REA, and BFT, obtained by fitting all 6.5 million SNPs at once, was 0.22 ± 0.01, 0.25 ± 0.01, 0.35 ± 0.01, and 0.15 ± 0.01, respectively. The aggregate genetic variance components estimated from the separate analysis were substantially larger than the corresponding heritability estimates, while the results of joint analysis for all partitioning factor were very close to h 2 estimates for all traits. A weak relationship was observed between chromosome length and its heritability (R 2 < 0.35). Although intergenic and intronic variants significantly contributed to the genetic variation of the traits, the variance captured per SNP was considerably lower for these variants compared to genic variants, particularly exon variants.

Leptospirosis is a widespread infection among pigs worldwide and in Ukraine in particular. In order to diagnose leptospirosis in animals, in most cases, only the serological method is used – the microagglutination reaction (MAT). From 2009 to 2024, 1497047 pig blood serum samples were tested in Ukraine by the PMA and 36507 positive reactions for leptospirosis were obtained, which is 2.4% of the studied livestock of this species. In the etiological structure, the dominant serological groups of leptospira were as follows: Icterohaemorrhagiae - 28.4%, Australis - 27.4%, Tarassovi - 4.0%, Canicola - 2.9% and Pomona - 2.6%. Antibodies to other serological groups were recorded in smaller numbers, namely: Grippotyphosa (1.8%), Sejroe (1.2%) and Hebdomadis (0.7%), so they played a secondary role in the etiologic structure. During the analyzed period, a large number of positive reactions with several serogroups of leptospira (mixed reactions) were observed, their number was 32.8 % of the total number of positive animals. The article presents a retrospective analysis of the circulation of eight main diagnostic serogroups of leptospira among the pig population in Ukraine: Sejroe, Hebdomadis, Tarassovi, Pomona, Grippotyphosa, Canicola, Icterohaemorrhagiae, Australis. The mapping of the territory of Ukraine for leptospirosis was carried out, which allows to evaluate the data and determine the risk zones of infection of pigs with leptospira of eight main diagnostic serogroups. It was found that they have a certain eco-regional confinement. The prevalence and etiological structure of porcine leptospirosis differed for each administrative (region) during the analyzed period. Thus, there was a decrease in the number of positive reactions to leptospira of the Australis, Pomona, Tarassovi, Canicola, Sejroe and Hebdomadis serogroups and an increase in the number of reactions to the Icterohaemorrhagiae and Grippotyphosa serogroups. Key words: leptospira, pigs, etiologic structure, serogroup, serovar, microagglutination test (MAT), mapping, GIS.

Kalanxoye degremona dorivor o‘simligining ildizidan 2ta, poyasidan 3ta va bargidan 3ta jami 8ta endofit izolyatlar ajratib olindi. Skrining natijasida Kalanxoye degremonadan ajratib olingan K7 izolyati tanlab olindi va MALDI TOF mass-spektrometriya usuli yordamida identifikatsiya qilindi. Tanlab olingan K7 bakteriya izolyati B.amyloliquefaciens ekanligi aniqlandi va B.amyloliquefaciens – UzMU 22 shtammi deb nomlandi. Bacillus amyloliquefaciens - UzMU 22 shtammining Verticillium dahliae, Alternaria alternata, Fusarium solani ва Fusarium oxysporum kabi patogen zamburug‘larga nisbatan antogonistik faolligi, kanamitsin, eritromitsin, sefotoksin, seprofloksatsin, gentamitsin va lenkomitsin kabi bir nechta antibiotiklarga sezgirligi va gidrolitik fermentlar faolligi aniqlandi.

The measures taken against tuberculosis (TB) in recent years in the Russian Federation have been highly effective. Unfortunately, the COVID-19 pandemic may seriously undermine the progress that has been made in the fight against TB. The aim of this study was to assess changes in the epidemiological rates of tuberculosis in the Russian Federation before and after the COVID-19 pandemic. Materials and methods. The analysis was conducted by considering the main epidemiological indicators of tuberculosis, according to the federal statistics for the period from 2017 to 2021. The parameters were estimated according to the data received from 11 areas in the North-Western region. Statistical analysis was carried out using the free software computing environment R (v.3.5.1) and the commercial software package Statistical Package for the Social Sciences (SPSS Statistics for Windows, version 24.0, IBM Corp., 2016). Research results. We found a positive correlation between the incidence among the overall population and the incidence among children aged 0–17, inclusively (r = 0.55 in 2017, r = 0.60 in 2020, and r = 0.53 in 2021). Along with the received regularities, a different trend is shown in the data analysis of general incidence and health X-ray examination for tuberculosis among the general population. The correlation has decreased threefold from 2017 (r = 0.72) to 2020 (r = 0.32); this negative trend might be the result of factors such as the quality of X-ray screening examinations among the general population, and the reduced assessment objectivity of the tuberculosis incidence rate. Conclusions. In assessing the correlation between general incidence and incidence in children under 17 years of age, as well as between incidence and mortality in the Russian Federation, a positive correlation was found with an increasing trend. Such a discrepancy might be due to decreases in the occupational health examination coverage among the general population. Therefore, in the years ahead, we can expect epidemiological indicators to increase incidence and mortality, including child mortality, associated with the insufficient detection of tuberculosis among the population during the COVID-19 pandemic.

O`simliklarning kasalliklardan himoya qilish maqsadida qishloq xo`jaligi ekinlarining hosildorligini oshirish va mahsulotning sifatini yaxshilashda muhim rol o`ynaydi.

The study of the Mirabilith deposit of the Azambur group, namely Lake Sakhare, allowed us to plan the experiment by mathematical planning of the experiment in order to obtain anhydrous sodium sulfate, conduct experimental studies and calculate a theoretical solution of the reaction. To do this, we selected the optimization parameter and the factors affecting it, according to which experiments were planned and conducted. The validity of the results obtained in the experiments was tested according to the criteria of Fischer, Kohren and Stiudent. After that a mathematical model of processes was chosen. This model was tested for adequacy of each experiment. After the relevant calculations confirmed the adequacy of the model, process optimization was carried out and parameters were selected to ensure the maximum solution of the reaction.