Characterization and expression of prohibitin during the mexican bean weevil (Zabrotes subfasciatus, Boheman, 1833) larvae development.

Prohibitin (PHB) is a highly conserved eukaryotic protein complex involved in multiple cellular processes. In insects, PHB has been identified as a potential target protein to insecticidal molecules acting as a receptor of PF2 insecticidal lectin in the midgut of Zabrotes subfasciatus larvae (bean pest) and Cry protein of Bacillus thuringiensis in Leptinotarsa decemlineata (Colorado potato beetle). This study aimed to characterize the structural features of Z. subfasciatus prohibitin (ZsPHB) by homology modeling and evaluate its expression and tissue localization at different stages of larval development both at the transcript and protein levels. The samples were collected from eggs and larvae of different developmental stages. The immunodetection of ZsPHB was done with anti-PHB1 and confirmed by LC-MS/MS analysis. Gene expression analysis of ZsPHB1 and ZsPHB2 was performed by RT-qPCR, and immunohistochemistry with FITC-labeled anti-PHB1. Results showed that ZsPHBs exhibit distinctive characteristics of the SPFH protein superfamily. The transcript levels suggest a coordinated expression of ZsPHB1 and ZsPHB2 genes, while ZsPHB1 was detected in soluble protein extracts depending on the stage of development. Histological examination showed ZsPHB1 is present in all larval tissues, with an intense fluorescence signal observed at the gut. These results suggest a physiologically important role of PHB during Z. subfasciatus development and show its regulation occurs at the transcriptional and post-transcriptional levels. This is the first characterization of PHB in Z. subfasciatus.

Prevalence and genotypic diversity of ostreid herpesvirus type 1 in Crassostrea gigas cultured in the Gulf of California, Mexico.

In bivalve mollusk aquaculture, massive disease outbreaks with high mortality and large economic losses can occur, as in northwest Mexico in the 1990s. A range of pathogens can affect bivalves; one of great concern is ostreid herpesvirus 1 (OsHV-1), of which there are several strains. This virus has been detected in the Gulf of California in occasional or sporadic samplings, but to date, there have been few systematic studies. Monthly samples of Crassostrea gigas, water, and sediment were taken in the La Cruz coastal lagoon and analyzed by PCR. The native mollusk, Dosinia ponderosa, which lives outside the lagoon, was sampled as a control. The virus was found throughout the year only in C. gigas, with prevalence up to 60%. In total, 9 genotype variants were detected, and genetic analysis suggests that linear genotypic evolution has occurred from strain JF894308, present in La Cruz in 2011. There has been no evidence of the entry of new viral genotypes in the recent past, thus confinement of the virus within the lagoons of the Gulf of California could promote a native genotypic diversity in the short term.

The Pacific oyster (Crassostrea gigas) Hsp70 modulates the Ostreid herpes virus 1 infectivity.

The Ostreid herpes virus type 1 (OsHV-1) is one of the most devastating pathogen in oyster cultures. Among several factors, as food limitation, oxygen depletion, salinity and temperature variations, episodes of "summer mortality" of the Pacific oyster Crassostrea gigas have also been associated with OsHV-1 infection. Mortalities of C. gigas spat and juveniles have increased significantly in Europe, and contemporary mortality records of this mollusk in México have been associated with the occurrence of OsHV-1. In the present study, the expression of the heat shock protein 70 gene from the Pacific oyster correlates with the abundance of DNA polymerase transcripts from the OsHV-1. This may suggest that the induction on the expression of the Pacific oyster hsp70 may potentially participate in the immune response against the virus. Furthermore, this study reports for the first time a TEM representative image of the OsHV-1 in aqueous solution, which possesses an icosahedral shape with a diameter of 70 nm × 100 nm. Finally, the examined sequence encoding the ORF4 of the OsHV-1 isolate from northwest Mexico showed specific sequence variations when compared with OsHV-1 isolates from distant geographical areas.

Seasonal changes in gene expression and polymorphism of hsp70 in cultivated oysters (Crassostrea gigas) at extreme temperatures.

The HSP70 proteins are an important element of the response against thermal stress and infectious diseases, and they are highly conserved and ubiquitous. In some species, variations on the hsp70 encoding sequence resulted in intraspecific differential expression, which leads to variations on thermo-tolerance among individuals. This phenomenon has not been described in the Pacific oyster Crassostrea gigas, which is cultivated in Mexico under temperature conditions highly above the optimal for this species. The present study was aimed to identify associations between hsp70 genotypes and their expression levels in C. gigas. By analyzing a 603 bp fragment from the 3' end of the hsp70 gene, 21 different genotypes with 60 nucleotide polymorphic sites were detected, of which 34 sites were found in heterozygous condition. Although no correlation was found between genotype-expression-season, a minimum expression threshold that should be taken into account as an important feature for a future breeding program is proposed.

G-C heterozygosis in mutS homolog2 as a risk factor to hereditary nonpolyposis colon cancer in the absence of a family medical history.

To detect the presence of point mutations in a small section of the mutS homolog2 (MSH2) gene in both healthy and affected persons treated at the General Hospital of the State of Sonora, a 353 base pair section of the MSH2 gene was amplified and sequenced from six persons affected by hereditary nonpolyposis colorectal cancer and from 19 healthy persons. The affected persons did not show the mutations reported in the scientific literature; however, six healthy persons were heterozygote and mutant-allele carriers. The heterozygote condition implies that carriers are candidates for the development of colorectal cancer. However, it is important to know the family medical history when investigating hereditary mutations.