ABSTRACT
AIMS: Waterborne outbreaks of hepatitis A and Norovirus disease have been reported and associated with contaminated water supply in various countries. However, in Mexico, there are no studies that report HAV and NV presence in water. This study reports the application of ultrafiltration and RT-nested PCR methods to concentrate and identify these viruses. METHODS AND RESULTS: Forty estuarine water samples were collected from the Huizache Caimanero Lagunary Complex. Samples were concentrated by ultrafiltration system (UFS) and RT-nested PCR was performed for HAV and NV identification. These viruses were found in 80% and 70% of the samples collected respectively and both were present in 57.5%. The DNA sequences analysis showed that 21 estuarine water samples were associated with HAV and 13 with NV. Faecal coliforms were isolated in 48.57% of the samples, while Escherichia coli were found in 34.28%. CONCLUSIONS: DNA sequencing showed that the genotype IB for HAV and GII for NV were predominant in México. No significant relationships were detected between indicators and viruses (P < 0.05). SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that the UFS is adequate for viral concentration. This is the first study analysing the genetic sequence of HAV and NV isolated from Mexican estuarine water.
Subject(s)
Hepatitis A virus/isolation & purification , Norovirus/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , Ultrafiltration/methods , Water Microbiology , Animals , Base Sequence , Enterobacteriaceae/isolation & purification , Escherichia coli/isolation & purification , Feces/microbiology , Feces/virology , Fisheries , Fresh Water/microbiology , Hepatitis A virus/classification , Hepatitis A virus/genetics , Humans , Hydrogen-Ion Concentration , Mexico , Molecular Sequence Data , Norovirus/classification , Norovirus/genetics , Phylogeny , RNA, Viral/genetics , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/instrumentation , Seasons , Seawater/microbiology , Temperature , Time Factors , Ultrafiltration/instrumentation , Water/chemistryABSTRACT
Conjugant pairs of Tetrahymena thermophila were mechanically separated by vigorous pipetting at the early stages of meiotic prophase. The complete sequence of conjugational nuclear events including the appearance of pronuclei, development of the new macronuclei (postzygotic development), and resorption of the old macronuclei was observed in the separated cells, without pronuclear exchange. The pronuclei in the separated cells were recognised by the presence of components of the extranuclear cytoskeleton, which were labelled with anti-tubulin and anti-fenestrin antibodies in the same way as in undisturbed conjugants. The apical region of the separated conjugants (the post-junction area), corresponding to the junction area of conjugants was labelled with anti-fenestrin antibody and maintained the properties required for the nuclear development. The results of the genetic study were consistent with a hypothesis that cytogamy (pronuclear fusion) was induced in the separated conjugants. Therefore, the lasting cell contact is not necessary for the successful completion of conjugational nuclear events.
Subject(s)
Cell Nucleus/physiology , Conjugation, Genetic , Tetrahymena thermophila/cytology , Tetrahymena thermophila/physiology , Animals , Cell Nucleus/genetics , Cell Nucleus/ultrastructure , Genotype , Meiosis , Models, Biological , Tetrahymena thermophila/genetics , Zygote/cytology , Zygote/physiologyABSTRACT
The total content of myosin heavy chain (MHC) and individual MHC isoforms were studied in 14-day denervated rat leg muscles: the slow-twitch (soleus) and fast-twitch (extensor digitorum longus and gastrocnemius) by biochemical methods. The weight of the denervated muscles decreased by about 50%, as compared to the control muscles. In all denervated muscles the total content of MHCs decreased, more so in the slow than in the fast muscles. We have observed that the proportion among the MHC isoforms changed: while MHC-1 and MHC-2B decreased, MHC-2A and MHC-2X increased. Taking into account muscle atrophy, the loss of MHC total content and the shift in pattern of MHC isoforms, the total net changes of the particular MHC isoforms were evaluated. It was found that the muscle content of each of the MHCs decreased after denervation, but their tissue concentration changed variously. The concentration of the MHC-1 and MHC-2B decreased in all denervated muscles, but that of the MHC-2A and MHC-2X changed variously, depending on the muscle. The concentration of MHC-2A decreased in the soleus and increased in the fast muscles, whereas the concentration of the MHC-2X changed inversely. In the denervated soleus a considerable amount of MHC-2X was expressed, while in the contralateral muscles this isoform was undetectable or appeared at trace levels.