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    Investigation of bacterial pathogens in milk from mastitic dairy cattle by matrix-assisted laser desorption ionization-time of flight mass spectrometry
    (Chulalongkorn Univ, 2022) Ozbey, Gokben; Otlu, Baris; Yakupogullari, Yusuf; Celik, Betul; Tanriverdi, Elif Seren; Kelestemur, Neslihan; Safak, Tarik
    The scope of the present study was to assess the use of Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry (MS) as a quick technique for the identification of bacterial species in mastitis. In this study, milk samples from each udder quarter from a total of 250 dairy cattle were aseptically collected and tested. The samples were grouped into California Mastitis Test (CMT) positive, CMT negative and clinical mastitis. The samples were streaked on blood agar and the bacterial isolates were analysed using MALDI-TOF MS. Using MALDI-TOF MS, certain species such as Staphylococcus chromogenes (44/188, 23.4%), Aerococcus viridans (40/188, 21.3%) and Staphylococcus haemolyticus (19/188, 10.1%) were identified at a higher proportion in milk samples from cattle that were CMT positive. Moreover, the most common bacteria isolated from CMT negative milk samples were A. viridans (56/161, 34.8%), S. haemolyticus (24/161, 14.9%) and S. chromogenes (17/161, 10.6%). Only one isolate of S. chromogenes (1/4, 25%), A. viridans (1/4, 25%), S. haemolyticus (1/4, 25%) and Enterococcus faecium (1/4, 25%) was detected from milk samples with clinical mastitis using MALDI-TOF MS. There was a concurrence between the MALDI-TOF and biochemical bacterial identification method in 325 of 353 samples (92.06%). This study concludes that MALDI-TOF can be applied for quick determination of bacterial isolates once the bacterial colony has been isolated in milk samples.
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    Protective role of vitamin E against acrylamide-induced testicular toxicity from pregnancy to adulthood: insights into oxidative stress and aromatase regulation
    (Springer, 2024) Uremis, Muhammed Mehdi; Gultekin, Sevinc; Uremis, Nuray; Safak, Tarik; cigremis, Yilmaz; Gul, Mehmet; Aydin, Muhterem
    Acrylamide (ACR) is a toxic chemical frequently encountered in daily life, posing health risks. This study aimed to elucidate the molecular-level mechanism of ACR's toxic effects on testicles and investigate whether Vitamin E can mitigate these effects. A total of 40 adult pregnant rats were utilized, divided into four groups: Control, ACR, Vitamin E, and ACR + Vitamin E. ACR and Vitamin E were administered to the mother rats during pregnancy and lactation, and to the male offspring until the 8th week post-birth. Serum hormone levels, oxidant-antioxidant parameters, histopathological examination of testicular tissue, and mRNA and protein levels of the testicular and liver aromatase gene were analyzed. Spermiogram analysis was conducted on the collected sperm samples from the male offspring. The results revealed that ACR exposure adversely affected hormone levels, oxidant-antioxidant parameters, histological findings, as well as aromatase gene and protein expressions. However, Vitamin E administration effectively prevented the toxic effects of ACR. These findings demonstrate that ACR application significantly impairs the reproductive performance of male offspring rats by increasing liver aromatase activity.