Валентин Митин

Acetic acid bacteria (AAB) are ubiquitous wine spoilage microorganisms causing significant economic damage to winemakers. Considering difficulties in their isolation through traditional microbiological methods, it would be advantageous to detect them using molecular methods at all stages of winemaking and, thus, prevent wine spoilage. In this research, we analyzed wines, musts and grapes of 13 varieties grown in different regions of the Republic of Moldova. The DNA was extracted and analyzed via PCR using home-designed primers to detect Acetobacter aceti and Acetobacter pasteurianus. Generally, samples with no detectable amounts of AAB in either musts or wine had volatile acidity within the acceptable limits. Only one grape (Rara Neagra) had detectable amounts of AAB (A. pasteurianus) at all analyzed stages (grape, must, wine), and this sample had the highest amount of volatile acidity (2.11 g/L), exceeding the maximum acceptable limit for red wines of 1.2 g/L. A. pasteurianus was more common than A. aceti, both in musts and wines. Samples positive for AAB but containing low amounts of them in wine (Cq value > 35) did not have volatile acidity above the acceptable level. Samples that were wine-negative but must-positive for AAB had volatile acidity close to the acceptable limit. This study shows the utility of PCR diagnostics for predicting the risks of wine spoilage by AAB.

Acetobacter aceti and Acetobacter pasteurianus belong to acetic acid bacteria (AAB), associated with wine spoilage. The timely detection of AAB, thought essential for their control, is however challenging due to the difficulties of their isolation. Thus, it would be advantageous to detect them using molecular methods at all stages of winemaking and storage. In this paper, we analyzed wines, musts and grapes of 13 varieties grown in different regions with Protected Geographical Indication of the Republic of Moldova for the presence of AAB, Acetobacter aceti and Acetobacter pasteurianus by real-time PCR and measured wine volatile acidity. Overall, the AAB content in the mature wine explained 33.7% of the variance in the volatile acidity of the mature wine, while the A. pasteurianus content in the mature wine alone explained 59.6% of the variability in the volatile acidity in the wine, and its content in the grapes, must and wine explained about 70% of the variance in the the volatile acidity. This makes A. pasteurianus a good candidate to be a potential predictor of wine volatile acidity.

Abstract Viruses and bacteria are the cause of a large number of different human diseases. It is believed that some of them may even contribute to the development of cancer. The present work is dedicated to the identification of mycoplasmas in patients with breast cancer. Mycoplasmas may participate in the development of several human diseases including chronic fatigue syndrome, acquired immunodeficiency syndrome, atypical pneumonia, etc. Moreover, there is a reason to believe that mycoplasma can participate in the development of cancer, leukemia and lymphoma. DNA samples from blood, saliva and tumor tissues of the Oncology Institute of Moldova patients diagnosed with breast cancer were analyzed. Mycoplasma testing was performed using nested PCR method. For Mycoplasma spp . detection, we used primers from the region of the 16S-23S RNA genes. The identification of Mycoplasma faucium , Mycoplasma salivarium and Mycoplasma orale was performed by nested PCR with primers for RNA polymerase beta subunit gene corresponding to mycoplasma. M.faucium and M.salivarius was found in saliva at about 100%, and M.or ale at a frequency of about 50%. Only M.faucium was found with the frequency of about 60% in the tissue of the patients. Moreover, a fairly high rate of detection of mycoplasma is observed both in the cases when primers for RNA polymerase gene and primers for 16S-23S RNA were used. We found M.faucium in tumor tissues of patients diagnosed with breast cancer. It is known that mycoplasmas are able to stimulate the synthesis of certain cytokines, which act as mitogenes on the cell. We assume that M.faucium can stimulate the mitogenes synthesis in breast tissues (e.g., cytokines) which, in turn, stimulate cell division and thus participate in the initiation of breast cancer.

Brettanomyces bruxellensis yeasts cause wine spoilage by producing volatile phenol compounds with specific off-odors. Assessing the propagation of this species is challenging, especially for micro-wineries. In this study, wines produced in a micro-winery from the grapes of different varieties collected from three PGI regions of Moldova over three years were studied for the presence and infection level of Brettanomyces spoilage yeasts, using traditional microbiological and molecular methods. The results of Brettanomyces infection monitoring in mature wines might speak in favor of the hypothesis that grape berries can be a potential source of B. bruxellensis in wine. The contamination levels of mature wines with respective species fluctuated in accordance with the year of grape cultivation, being the highest during the 2023 vintage. This study shows the potential of applying sequencing analysis for tracking the source of Brettanomyces contamination in wineries.

The article focuses on real-time PCR detection and quantification of Fusarium spp., potential producer of class B fumonisin mycotoxins in mature corn kernels using primers designed to genes FUM1 and FUM6, involved in mycotoxin biosynthesis. Research have shown that the real-time PCR assay can be used for detecting and quantifying potentially mycotoxigenic Fusarium in the maize kernels by the genes involved in mycotoxin synthesis. Three pairs of primers specific to genes involved in the synthesis of mycotoxin FB known to contaminate maize and maize products were developed and a pair of primers specific to a conserved Fusarium beta-tubulin gene, aimed at detection of most Fusarium species. There has been applied quantitative PCR assay for quantification of total Fusarium spp. and potentially mycotoxigenic Fusarium verticillioides.