Ethanol Alleviates Amyloid-β-Induced Toxicity in an Alzheimer’s Disease Model of Caenorhabiditis elegans

Amyloid-β, a hallmark of Alzheimer’s disease, forms toxic intracellular oligomers and extracellular senile plaques resulting in neuronal toxicity. Ethanol is widely consumed worldwide. Moderate ethanol consumption has numerous benefits in humans. We found that ethanol could significantly extend the lifespan of Caenorhabiditis elegans in a previous study. Based on that study, we tested the effect of ethanol on Alzheimer’s disease transgenic Caenorhabiditis elegans strain CL4176, which expresses amyloid-β1-42 peptide in body wall muscle cells. Ethanol delayed paralysis and reduced amyloid-β oligomers in Caenorhabiditis elegans worms of the CL4176 strain. Moreover, ethanol could induce the nuclear translocation of DAF-16 in the nematodes. However, in worms that were fed daf-16 RNAi bacteria, ethanol no longer delayed the paralysis. The qPCR assays showed that ethanol increases the expression of daf-16, hsf-1 and their common target genes- small heat shock protein genes. In addition, we also found that ethanol could increase lysosome mass in the CL4176 worms. In summary, our study indicated that ethanol attenuated amyloid-β toxicity in the Alzheimer’s disease model of Caenorhabiditis elegans via increasing the level of lysosomes to promote amyloid-β degradation and upregulating the levels of small heat shock protein genes to reduce amyloid-β aggregation.

Transcriptomic Analysis of Stropharia Rugosoannulata Reveals Potential Carbohydrate Metabolism and Cold Resistance Mechanisms Under Low-Temperature Stress

Low temperature is an important environmental factor that restricts the growth of Stropharia rugosoannulata; however, the molecular mechanisms underlying S. rugosoannulata responses to low-temperature stress are largely unknown. In this study, we performed a transcriptome analysis of a high-sensitivity strain (DQ-1) and low-sensitivity strain (DQ-3) under low-temperature stress. The liquid hyphae of S. rugosoannulata treated at 25°C and 10°C were analyzed by RNA-Seq, and a total of 9499 differentially expressed genes (DEGs) were identified. GO and KEGG enrichment analyses showed that these genes were enriched in “xenobiotic biodegradation and metabolism”, “carbohydrate metabolism”, “lipid metabolism” and “oxidoreductase activity”. Further research found that carbohydrate enzyme (AA, GH, CE, and GT) genes were downregulated more significantly in DQ-1 than DQ-3 and several cellulase activities were also reduced to a greater extent. Moreover, the CAT1, CAT2, GR, and POD genes and more heat shock protein genes (HSP20, HSP78 and sHSP) were upregulated in the two strains after low-temperature stress, and the GPX gene and more heat shock protein genes were upregulated in DQ-3. In addition, the enzyme activity and qRT–PCR results showed trends similar to those of the RNA-Seq results. This result indicates that low-temperature stress reduces the expression of different AA, GH, CE, and GT enzyme genes and reduces the secretion of cellulase, thereby reducing the carbohydrate metabolism process and mycelial growth of S. rugosoannulata. Moreover, the expression levels of different types of antioxidant enzymes and heat shock proteins are also crucial for S. rugosoannulata to resist low-temperature stress. In short, this study will provide a basis for further research on important signaling pathways, gene functions and variety breeding of S. rugosoannulata related to low-temperature stress.

Expression of heat shock protein genes Aaehsp26, Aaehsp83 and Aaehsc70 in response to thermal stress in Aedes aegypti larvae

Climate change is responsible to a certain extent for the occurrence and spread of arboviral pathogens worldwide. Temperature is one of the crucial abiotic factors influencing the physiological processes of mosquitoes. Several genes of heat shock protein (AaeHsp26, AaeHsp83, and AaeHsc70) families are known to be expressed in mosquitoes, which aid in overcoming stress induced by elevated temperature. In this study, the relative expression of heat shock protein genes has been examined using Quantitative Real-time PCR (qPCR). The temperatures used for heat shock treatment were 27(control), 37, and 42°C for 1 hour heat shock period and applied to 3rd instar larvae. Significant up-regulation has been seen at 37, and 42°C. The highest expression level, about 82.43 fold, was reported for the AaeHsc70 gene at 42°C followed by 78.36 fold for AaeHsp26 at 37°C and 4.79 fold for AaeHsp83 at 42°C. The current study has shown that HSPs are important markers of stress and may function as critical proteins to protect and enhance the survival of Ae. aegypti larvae and pupae. Biological implications of these findings could impact the vector competencies Dhaka Univ. J. Biol. Sci. 30(2): 233-241, 2021 (July)

Evolution of tissue and developmental specificity of transcription start sites in Bos taurus indicus

To further the understanding of the evolution of transcriptional regulation, we profiled genome-wide transcriptional start sites (TSSs) in two sub-species, Bos taurus taurus and Bos taurus indicus, that diverged approximately 500,000 years ago. Evolutionary and developmental-stage differences in TSSs were detected across the sub-species, including translocation of dominant TSS and changes in TSS distribution. The 16% of all SNPs located in significant differentially used TSS clusters across sub-species had significant shifts in allele frequency (472 SNPs), indicating they may have been subject to selection. In spleen and muscle, a higher relative TSS expression was observed in Bos indicus than Bos taurus for all heat shock protein genes, which may be responsible for the tropical adaptation of Bos indicus.