Analysis of Genetic Determination of <I>Vibrio cholerae</I> Tweenase Activity

Studied are Vibrio cholerae of different serogroups on the presence of cef (CHO cell elongating factor) gene and activity against tweens and tributyrin using HDS-agar, prepared on the basis of bakery yeast pancreatic digest. Determined is the fact that all cef-positive strains hydrolyze tweens 20, 40, 60, 80, 85 and all but toxigenic V.cholerae O139, hydrolyze tributyrin. In contrast, non-toxigenic cef-negative strains of O139 serogroup, are active only against the latter. Apparently, the tweenase activity of Vibrio cholerae is provided, partly, by Cef, and the ability to hydrolyze tributyrin is the result of combined activity of Cef and other ferments. Shown is the efficiency of HDS-agar application to determine these characteristics

Determination of E102, E110, Е122, E124 synthetic dyes in soft drinks by modified piezosensors

A method for the determination of synthetic dyes (tartrazine E102, yellow “solar sunset” E110, azorubin E122, ponso 4R E124) in soft drinks using piezoelectric sensors based on the molecularly imprinted polymers (MIP) is proposed. The values of the imprinting factor and the coefficients of selectivity of the obtained molecularly imprinted polymers of synthetic dyes are compared. The selectivity of the modified sensors to template molecules in the model and binary mixtures of synthetic dyes has been studied. It was shown that a sensor with the molecular imprint is the most sensitive to the dye that was the template for obtaining the selective coating. The additive method showed the absence of the “matrix” influence of the object (dye) on the value of the analytical signal of the sensors based on the polymers with molecular prints. The results of the determination of synthetic dyes by piezoelectric sensors with the standard techniques (spectrophotometry and thin-layer chromatography) were compared; it was shown that the difference in the determination results does not exceed 10%. According to its metrological characteristics, the method for determining synthetic dyes by piezoelectric sensors with MIP is in satisfactory agreement with the method of spectrophotometry.Предложен способ определения синтетических красителей (тартразин Е102, желтый «солнечный закат» Е110, азорубин Е122, понсо 4R Е124) в безалкогольных напитках с помощью пьезоэлектрических сенсоров на основе полимеров с молекулярными отпечатками (ПМО). Предел обнаружения составил 0.02-0.2 мг/дм3. В качестве прекурсора при синтезе ПМО использовали полиимид ПМ. Проведено сравнение значений импринтинг-фактора и коэффициентов селективности полученных полимеров с молекулярными отпечатками синтетических красителей. Изучена избирательность модифицированных сенсоров к молекулам-шаблонам в модельных и бинарных смесях синтетических красителей, при этом сенсор с молекулярным отпечатком наиболее чувствителен к тому красителю, который был шаблоном при получении селективного покрытия. Методом добавок установлено отсутствие влияния матрицы объекта (красителя) на величину аналитического сигнала сенсоров на основе полимеров с молекулярными отпечатками. Проведено сравнение результатов определения синтетических красителей пьезоэлектрическими сенсорами на основе ПМО со стандартными методиками (спектрофотометрия и тонкослойная хроматография), показано, что разность результатов определения не превышает 10 %. По своим метрологическим характеристикам методика определения синтетических красителей пьезоэлектрическими сенсорами с ПМО удовлетворительно согласуется с методом спектрофотомерии

Alkyl Sulfatase of Cholera Vibrios

The aim of the work was to study the structure of the alkyl sulfatase (asu) gene in Vibrio cholerae strains of various serogroups, as well as to compare nucleotide and amino acid sequences of alkyl sulfatases using various methods of bioinformatic analysis.Materials and methods. 483 strains of V. cholerae O1, O139 and nonO1/nonO139 serogroups were employed in the work. The search for the gene, its recurrence, and localization was carried out applying the Blast software. The nucleotide and corresponding amino acid sequences of the gene, as well as its structure, were studied using bioinformatic analysis. Sequencing was performed on the MiSeq (Illumina) platform. The enzymatic activity was detected using a medium, confirming the presence/absence of the gene by PCR in vitro and in silico.Results and discussion. Bioinformatic analysis of the nucleotide and corresponding amino acid sequences of the asu gene has been carried out and its structure investigated. Four functional domains have been identified. In the beta-lactamase domain, a conservative amino acid sequence -HAHADH- has been found in all strains of cholera vibrios, which is part of the Zn2+ binding motif. It has been established that the alkyl sulfatase of cholera vibrios belongs to the family of Zn2+-dependent β-lactamases. Blast analysis has revealed the similarity of nucleotide and amino acid sequences of alkyl sulfatases in representatives of V. cholerae O1 and O139 serogroups (ctxAB+tcpA+) and representatives of the genera Aeromonas and Pseudomonas, which is in the line with the data of 3D modeling of the amino acid sequence structures of the alkyl sulfatase enzyme in these microorganisms. The bioinformatic analysis of nucleotide and amino acid sequences of alkyl sulfatases in cholera vibrios has showed the conservativeness of these sequences in toxigenic strains and the presence of a number of single mutations in the asu gene in atoxigenic ones. The presence or absence of the asu gene has been established by PCR in vitro and in silico and confirmed by the results obtained using the Blast program. It is demonstrated that the presence/absence of the asu gene correlates with the ability/inability of O139 strains to hydrolyze SDS on the medium. These results can be used in studying mechanisms of cholera vibrios adaptation, persistence and pathogenicity

Robust image analysis with sparse representation on quantized visual features

10.1109/TIP.2012.2219543IEEE Transactions on Image Processing223860-871IIPR