Development of a nucleic acid lateral flow immunoassay for simultaneous detection of Listeria spp. and Listeriamonocytogenes in food

We present a new nucleic acid lateral flow immunoassay (NALFIA) for the assessment of listeria contamination. The detection procedure starts with enrichment of sample in Half Fraser broth (24 h). Following isolation of DNA, a duplex PCR is performed with two labelled primer sets, one generic and directed to a specific sequence of the gene encoding 16S rRNA from Listeria spp. and the other specific and directed to a part of the prfA gene encoding the central virulence gene regulator from the food pathogen Listeria monocytogenes (3.5 h). The PCR solution is directly added to the one-step assay device and the appearance of a grey/black line is indicative of the presence of specific amplicons (max 15 min). In all tests performed, the method correctly identified L. monocytogenes and strains of Listeria spp. PCR material of over 20 food samples was tested by NALFIA. The method proved to be useful for the detection of L. monocytogenes in different kinds of food sample

Nucleic Acid Lateral Flow Immunoassay for the Detection of Pathogenic Bacteria from Food

Nucleic acid lateral flow immunoassay (NALFIA) is a method combining molecular biological principle of detection with immunochemical principle of visualisation. Following isolation of DNA from the sample, a duplex PCR with two primer sets, of which one was labelled with biotin and the other with digoxigenin or fluorescein, respectively, was performed. The PCR solution and carbon particles conjugated with avidin are directly added to the nitrocellulose membrane with two test lines of immobilised antibodies specific for digoxigenin and fluorescein. The appearance of a black line indicates the presence of specific amplicon. We would like to present the NALFIA for the simultaneous detection of L. monocytogenes in particular and the genus Listeria in general, in food. Bacteria from the genus Listeria frequently contaminate a large variety of foods. Occurrence of Listeria strains in food may indicate errors in good hygienic and manufacturing practice, only L. monocytogenes is a significant human and animal pathogen responsible for the serious illness listeriosis. Conventional microbiological methods for L. monocytogenes detection are laborious and take several days to achieve a confirmed identification

Роль інтелектуальної культури в процесі професійної підготовки майбутнього фахівця

Зниження рівня професійної підготовки фахівців у вищих навчальних закладах сьогодні є актуальною проблемою вищої освіти на всьому пострадянському просторі. І не в останню чергу ця проблема пов’язується з рівнем інтелекту студентської молоді

Украина — член международной комиссии по блоьшим плотинам

Within Herd Test Prevalence Affects Genetic Variation in Antibody Response to Mycobacterium avium Subspecies paratuberculosis in Milk of Dutch Holstein-Friesians - K.J.E. van Hulzen, M. Nielen, A.P. Koets, G. de Jong, J.A.M. van Arendonk and H.C.M. Heuven. Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands. Worldwide, classical control strategies based on hygiene and culling of infected animals have not been able to eradicate Johne’s disease. Therefore, breeding for disease resistance may be a useful tool to contribute to control the disease. In this study, genetic parameters were estimated for the presence of a Mycobacterium avium subspecies paratuberculosis specific antibody response in milk of Dutch Holstein-Friesians using subsets of data based on within herd test prevalence levels. The estimated heritability ranged from 3.1% for the complete dataset to 9.7% for herds with a minimum test prevalence of 10%. Cross-validation analysis showed that breeding values were predicted most accurately using data obtained from herds with at least 2 positive tested animals, hence a heritability of 4.1% (± 0.4)

Amorphous carbon nanoparticles: a versatile label for rapid diagnostic (immuno)assays

Carbon nanoparticles (CNPs) labeled with reporter molecules can serve as signaling labels in rapid diagnostic assays as an alternative to gold, colored latex, silica, quantum dots, or up-converting phosphor nanoparticles. Detailed here is the preparation of biomolecule-labeled CNPs and examples of their use as a versatile label. CNPs can be loaded with a range of biomolecules, such as DNA, antibodies, and proteins (e.g., neutravidin or a fusion protein of neutravidin with an enzyme), and the resulting conjugates can be used to detect analytes of high or low molecular mass

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted

Влияние фенилгидразина и алкилсульфатов на осмотическую чувствительность эритроцитов млекопитающих

Показано, что чувствительность эритроцитов млекопитающих к гипертоническому стрессу при 37 °С после обработки фенилгидразином зависит от видовой принадлежности клеток. Установлено, что модификация фенилгидразином эритроцитов млекопитающих приводит к снижению антигемолитической активности алкилкилсульфатов в условиях гипертонического стресса.Показано, що чутливість еритроцитів ссавців до гіпертонічного стресу при 37 °С після обробки фенілгідразином залежить від видової приналежності клітин. Встановлено, що модифікація фенілгідразином еритроцитів ссавців призводить до зниження антигемолітичної активності алкілсульфатів в умовах гіпертонічного стресу.It is shown that the sensitivity of mammalian erythrocytes to hypertonic stress at 37 °C after the treatment with phenylhydrazine depends on the species of a cell. We have established that the modification with phenylhydrazine of mammalian erythrocytes leads to a decrease of the alkyl sulfates antihemolytic activity under hypertonic stress

Infectious Bronchitis Virus induces acute interferon-gamma production through polyclonal stimulation of chicken leukocytes

AbstractInfectious Bronchitis Virus, a member of the Coronaviridae, is a respiratory pathogen in poultry. We found that in vitro stimulation with IBV resulted in ChIFN-γ production in splenocytes of both infected birds and uninfected birds. The non-specific stimulation did not occur when other avian viruses or other coronaviruses were used or when mammalian cells were stimulated with IBV. Inactivation of IBV reduced ChIFN-γ production, but ChIFN-γ remained elevated compared to unstimulated cells. An increase in ChIFN-γ mRNA was detected in splenocytes from IBV-infected and uninfected chickens as early as 1 h after stimulation with IBV. These results indicate that IBV acts as a polyclonal stimulus, inducing a rapid production of IFN-γ even without previous exposure to the virus

Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations

peer-reviewedBackground: Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland. Methods: The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population. Results and discussion: The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively. Conclusions: Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values