Warming and Salt Intrusion Affect Microcystin Production in Tropical Bloom-Forming Microcystis

The Vietnamese Mekong Delta is predicted to be one of the regions most impacted by climate change, causing increased temperature and salinity in inland waters. We hypothesized that the increase in temperature and salinity may impact the microcystin (MC) production of two Microcystis strains isolated in this region from a freshwater pond (strain MBC) and a brackish water pond (strain MTV). The Microcystis strains were grown at low (27 °C), medium (31 °C), high (35 °C) and extremely high (37 °C) temperature in flat photobioreactors (Algaemist). At each temperature, when cultures reached a stable state, sea salt was added to increase salinity to 4‰, 8‰, 12‰ and 16‰. MC concentrations and cell quota were reduced at high and extremely high temperatures. Salinity, in general, had comparable effects on MC concentrations and quota. At a salinity of 4‰ and 8‰, concentrations of MC per mL of culture and MC cell quota (based on chlorophyll, dry-weight and particle counts) were higher than at 0.5‰, while at the highest salinities (12‰ and 16‰) these were strongly reduced. Strain MBC produced five MC variants of which MC-RR and MC-LR were most abundant, followed by MC-YR and relatively low amounts of demethylated variants dmMC-RR and dmMC-LR. In strain MTV, MC-RR was most abundant, with traces of MC-YR and dmMC-RR only in cultures grown at 16‰ salinity. Overall, higher temperature led to lower MC concentrations and cell quota, low salinity seemed to promote MC production and high salinity reduced MC production. Hence, increased temperature and higher salinity could lead to less toxic Microcystis, but since these conditions might favour Microcystis over other competitors, the overall biomass gain could offset a lower toxicity.     

Association of a novel polymorphism in the bovine PPARGC1A gene with growth, slaughter and meat quality traits in Brangus steers

The PPARGC1A gene (peroxysome proliferator-activated receptor-γ coactivator 1α gene) controls muscle fiber type and brown adipocyte differentiation; therefore, it is a candidate gene for beef quality traits (tenderness and fat content). Two SNPs (Single Nucleotide Polymorphisms) were identified within exon 8 by multiple alignment of DNA sequences obtained from 24 bulls: a transition G/A (SNP 1181) and a transversion A/T (SNP 1299). The SNP 1181 is a novel SNP, corresponding to a non-conservative substitution (AGT/AAT) that could be the cause of amino acid substitution (³⁶⁴Serine/³⁶⁴Asparagine). A Mismatch PCR method was designed to determine genotypes of 73 bulls and 268 steers for SNP 1181. Growth, slaughter and meat quality information were available for the group of steers. Allele A of SNP 1181 was not found in Angus. In 243 steers, no significant differences (P > 0.05) were found for either final live body weight, gain in backfat thickness in Spring, kidney fat weight, kidney fat percentage, Warner–Bratzler shear force at 7 days postmortem, intramuscular fat percentage or meat colour between genotype GG and AG. This SNP could be included in breed composition and population admixture analyses because there are marked differences in allelic frequencies between Bos taurus and Bos indicus breeds.     

What is the value of integrating the idea of certainty into continuous evaluation?]

A student, future decision-maker, has to measure the consequences of his indecision. In this study, a model of work with doubt is tested. We observe that the indecision is correlate with knowledge. His taking into consideration from continuous assessments allows us to predict his academic standard.