Identification of microRNAs involved in drought stress responses in early-maturing cotton by high-throughput sequencing

Abstract

Drought stress is one of the most important abiotic stresses. Cotton is classified as drought tolerant crop but the regulatory mechanism is unknown. MicroRNAs (miRNAs) have been implicated important roles in stress responses in many plants. However, the study of miRNAs in cotton responsive to drought stress is limited, especially in early-maturing cotton. In this study, we performed deep sequencing of small RNAs to identify known and novel miRNAs involved in the regulation of drought stress and understand the expression profile of miRNAs in early-maturing cotton. Three cotton small RNA libraries: non-stressed Shizao1 (early-maturing cotton variety) library (NSS), drought-stressed Shizao1 library (DSS) and non-stressed Jimian958 (medium-maturing cotton variety) library (NSJ) were constructed for deep sequencing. As a result, we identified a total of 64 known and 67 novel miRNAs in the 3 libraries and 88 of them were dramatically differentially expressed (greater than twofold) during drought stress. In addition, we found the expression of 41 miRNAs increased or reduced more than twofold in early-maturing cotton variety compared with that in medium-maturing cotton variety. Our results significantly increased the number of miRNAs in cotton and revealed for the first time the expression profile of miRNAs for early-maturing cotton.

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In vivo evidence on the functional variation within fatty acid synthase gene associated with lipid metabolism in bovine longissimus dorsi muscle tissue

Abstract

In Korean cattle, intramuscular fat (IMF), or marbling, of the longissimus dorsi muscle (LM) cross section is one of the most important indicators of beef quality and are influenced by environmental and genetic factors. This study was to evaluate the effect of SNPs on the beef quality in Korean cattle for functional studies, such as site-directed mutagenesis based on bovine adipocytes. The fatty acid synthase (FASN) gene plays an important role in lipogenesis. FASN is an essential metabolic and multifunctional enzyme in fatty acid synthesis. Several studies have reported that SNPs g.841G, g.16024A, g.16039T, and g.17924G have a significant impact on marbling scores in Korean cattle and Japanese Black cattle population. These SNPs are located in transcription factor binding sites, the beta-ketoacyl reductase, and thioesterase domains. Our results revealed that the g.17924 A>G SNP is located in the thioesterase domain of the FASN protein, and changes from polar, neutral, and hydrophilic to nonpolar, aliphatic, and hydrophobic, respectively. In in vivo LM tissue of Korean cattle, the g.17924A>G SNP has an effect on increasing fat deposition. Therefore, g.17924A>G SNP could be a causal mutation for increasing fat deposition in Korean cattle LM tissue.

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Characterization of the dynamic change of microRNA expression in mice hypothalamus during the time of female puberty

Abstract

Puberty onset is a milestone in sexual development. A tumor suppress gene (TSG) network had been reported to be involved in the regulation of female puberty onset. The observations in rodents and primates showed a potential link between microRNAs and puberty onset. To figure out what miRNAs play roles in this important biological process, profilings of microRNAs in the hypothalamus of female mice from three different pubertal stages, juvenile [postnatal day (P10)], early pubertal (P25) and pubertal (P30) were performed on the Affymetrix GeneChip miRNA 3.0 Arrays, the cerebral cortex (CTX) was used as a control tissue. 20 miRNAs were shown to be differentially expressed in hypothalamus (fold change > 1.5, P < 0.05), but not in CTX during the transition from juvenile to pubertal. Four of them were validated by real-time quantitative RT-PCR (qRT-PCR) method. 1018 genes were predicted as the targets of these miRNAs. Further bioinformatics analysis suggested that these target genes were involved in many important signaling pathways, especially in the cancer related pathways. We also found that about 90% of these target genes were expressed in the hypothalamus, as well as in the immortalized GnRH-producing GT1-7 cells, which provided additional evidence that these miRNAs could be female puberty onset related. Here we present a novel comprehensive data set of miRNA gene expression during the puberty onset; and it provides an important recourse for the future functional characterization of individual miRNAs and their targets in mouse hypothalamus and in GT1-7 cells.

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Acute intermittent hypoxia with concurrent hypercapnia evokes P2X and TRPV1 receptor dependent sensory long-term facilitation in naïve carotid bodies

Abstract

Apneas constitute an acute existential threat to neonates and adults. In large part, this threat is detected by the carotid bodies, the primary peripheral chemoreceptors, and combatted by arousal and acute cardiorespiratory responses, including increased sympathetic output. Similar responses occur with repeated apneas but they continue beyond the last apnea and can persist for hours (i.e. ventilatory and sympathetic LTF). These long-term effects may be adaptive during acute episodic apnea, but may prolong hypertension causing chronic cardiovascular impairment. We report a novel mechanism of acute carotid body (CB) plasticity (sensory LTF) induced by repeated apnea-like stimuli i.e. acute intermittent hypoxia with concurrent hypercapnia (AIH-Hc). This plasticity did not require chronic intermittent hypoxia (CIH) preconditioning, was dependent on P2X receptors and PKC, and involved heat-sensitive TRPV1 receptors. ROS (O₂·⁻) were involved in initiating plasticity only; no evidence was found for H₂O₂ involvement. Angiotensin II and 5HT receptor antagonists, losartan and ketanserin, severely reduced CB responses to individual hypoxic-hypercapnic challenges and prevented induction of sLTF but, if applied after AIH-Hc, failed to reduce plasticity-associated activity. Conversely, TRPV1 receptor antagonism had no effect on responses to individual hypoxic-hypercapnic challenges but reduced plasticity-associated activity by ∼50%. Further, TRPV1 receptor antagonism in vivo reduced sympathetic LTF caused by AIH-Hc, but only if the CBs were functional. These data demonstrate a new mechanism of CB plasticity and suggest P2X-TRPV1 dependent sensory LTF as a novel target for pharmacological intervention in some forms of neurogenic hypertension associated with recurrent apneas.

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Kairomones from an estuarine fish increase visual sensitivity in brine shrimp ( Artemia franciscana) from Great Salt Lake, Utah, USA

Abstract

Chemical cues from fish, or kairomones, often impact the behavior of zooplankton. These behavioral changes are thought to improve predator avoidance. For example, marine and estuarine crustacean zooplankton become more sensitive to light after kairomone exposure, which likely deepens their vertical distribution into darker waters during the day and thereby reduces their visibility to fish predators. Here, we show that kairomones from an estuarine fish induce similar behavioral responses in adult brine shrimp (Artemia franciscana) from an endorheic, hypersaline lake, Great Salt Lake, Utah, USA. Given downwelling light stimuli, kairomone-exposed A. franciscana induce a descent response upon dimmer light flashes than they do in the absence of kairomones. Using extracellular electroretinogram (ERG) recordings, we also find that kairomones induce physiological changes in the retina that may lead to increased visual sensitivity, suggesting that kairomone-induced changes to photobehavior are mediated at the photoreceptor level. However, kairomones did not induce structural changes within the eye. Although A. franciscana inhabit endorheic environments that are too saline for most fish, kairomones from an estuarine fish amplify photobehavior in these branchiopod crustaceans. The mechanism for this behavioral change has both similarities to and differences from that described in marine malacostracan crustaceans.

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The ubiquity of pleiotropy in human disease

Abstract

Pleiotropy has long been thought to be a common phenomenon in the human genome; however, until recently appropriate data was unavailable to test this hypothesis. Prior studies focused on assessing the prevalence of pleiotropy in only small subsets of phenotypes (≤ 53 phenotypes), without a truly comprehensive assessment of pleiotropy in the human genome. In this study, we determined the prevalence of pleiotropy, using the entire GWAS catalog (1094 disease phenotypes, 14,459 genes), as well as investigate the relationship between the degree of pleiotropy and the average effect size for each associating gene. The number of associating phenotypes per gene ranged from 1 to 53, with 44% of genes reported in the GWAS catalog associating with more than one phenotype. The proportion of genes shown to be pleiotropic has continued to increase as more studies are added to the catalog. We also found the degree of pleiotropy scales positively with a gene's average effect size (r = 0.04, p value = 0.0003) and negatively with the variance of effect sizes in genes with a given number of associating phenotypes (r = − 0.590, p value = 0.0019). Based on this and prior work, it is becoming evident that pleiotropy is a common, if not ubiquitous, phenomenon. These results have implications in understanding disease etiologies, potentially common biology underlying even disparate diseases, and in elucidating the genotype–phenotype map.

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GABA concentration in sensorimotor cortex following high-intensity exercise and relationship to lactate levels

Abstract

High-intensity exercise increases the concentration of circulating lactate. Cortical uptake of blood borne lactate increases during and following exercise, however the potential relationship with changes in the concentration of neurometabolites remains unclear. While changes in neurometabolite concentration have previously been demonstrated in primary visual cortex following exercise, it remains unknown whether these changes extend to regions such as sensorimotor cortex (SM) or executive regions such as dorsolateral prefrontal cortex (DLPFC). Here we explored the acute aftereffects of high-intensity interval training (HIIT) on the concentration of gamma-amino butyric acid (GABA), a combined glutamate-glutamine-glutathione spectral peak (Glx), and their balance in SM and DLPFC, as well as the relationship to blood lactate levels. Following HIIT, there was a robust increase in GABA concentration in sensorimotor cortex, evident across the majority of participants. This change was not observed in DLPFC. Furthermore, the increase in sensorimotor cortex GABA was positively correlated with an increase in blood lactate. There were no changes in Glx concentration in either region. The observed increase in sensorimotor cortex GABA concentration implies functional relevance while the correlation with lactate levels may relate to the metabolic fate of exercise-derived lactate that crosses the blood-brain barrier.

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