Abstract Rhodotorula sp. (USM-PSY62) is a psychrophilic yeast isolated from Antarctic sea ice and it grows optimally at 15 °C. This study was set up to observe how USM-PSY62 adapted to fluctuations in temperature. During cold adaptation, an elevated transcription of the CorA magnesium transporter gene in USM-PSY62 indicated a higher requirement for magnesium ions in order to gain additional enzyme cofactors or maintain cytoplasmic fluidity. The HepA homologue coding for DNA/RNA helicase was also over-expressed in cold condition possibly to reorganize secondary structures of DNA and RNA. An up-regulation of the catalase gene was also observed reflecting an increment in the concentration of reactive oxygen species and fluctuations in the associated antioxidant system. The YOP1 gene, which encodes a membrane protein associated with protein transport and membrane traffic, was the most down-regulated under cold shock condition. The genes responsible for the structural maintenance of chromosome ( SMC ) were also down-regulated when the temperature was shifted to 0 °C. Upon cold shock, the gene for heat shock factor protein 1 ( HSF 1) was also down-regulated. Hsf1 is a transcriptional regulator which regulate the heat shock responses. Although USM-PSY62 showed some common adaptive strategies as in several other psychrophilic organisms, new mechanisms were also uncovered.
The aim of this study was to evaluate the molecular mechanisms of Lactobacillus strains in improving ageing of the musculoskeletal system. The anti‐ageing mechanism of three probiotics strains Lactobacillus fermentum DR9, Lactobacillus paracasei OFS 0291 and L. helveticus OFS 1515 were evaluated on gastrocnemius muscle and tibia of d‐galactose‐induced ageing rats. Upon senescence induction, aged rats demonstrated reduced antioxidative genes CAT and SOD expression in both bone and muscle compared to the young rats (P < 0·05). Strain L. fermentum DR9 demonstrated improved expression of SOD in bone and muscle compared to the aged rats (P < 0·05). In the evaluation of myogenesis‐related genes, L. paracasei OFS 0291 and L. fermentum DR9 increased the mRNA expression of IGF‐1; L. helveticus OFS 1515 and L. fermentum DR9 reduced the expression of MyoD, in contrast to the aged controls (P < 0·05). Protective effects of L. fermentum DR9 on ageing muscle were believed to be contributed by increased AMPK‐α2 expression. Among the osteoclastogenesis genes studied, TNF‐α expression was highly elevated in tibia of aged rats, while all three probiotics strains ameliorated the expression. Lactobacillus fermentum DR9 also reduced the expression of IL‐6 and TRAP in tibia when compared to the aged rats (P < 0·05). All probiotics treatment resulted in declined proinflammatory cytokines IL‐1β in muscle and bone. Lactobacillus fermentum DR9 appeared to be the strongest strain in modulation of musculoskeletal health during ageing. The study demonstrated the protective effects of the bacteria on muscle and bone through antioxidative and anti‐inflammatory actions. Therefore, L. fermentum DR9 may serve as a promising targeted anti‐ageing therapy.
Abstract The Southern house mosquito, Culex quinquefasciatus ( Cx. quinquefasciatus ) is an important vector that transmit multiple diseases including West Nile encephalitis, Japanese encephalitis, St. Louis encephalitis and lymphatic filariasis. Long noncoding RNAs (lncRNAs) involve in many biological processes such development, infection, and virus-host interaction. However, there is no systematic identification and characterization of lncRNAs in Cx. quinquefasciatus . Here, we report the first ever lncRNA identification in Cx. quinquefasciatus . By using 31 public RNA-seq datasets, a total of 4,763 novel lncRNA transcripts were identified, of which 3,591, 569, and 603 were intergenic, intronic, and antisense respectively. Examination of genomic features revealed that Cx. quinquefasciatus shared similar characteristics with other species such as short in length, low GC content, low sequence conservation, and low coding potential. Furthermore, compared to protein-coding genes, Cx. quinquefasciatus lncRNAs had lower expression values, and tended to be expressed in temporally-specific fashion. In addition, weighted correlation network and functional annotation analyses showed that lncRNAs may have roles in blood meal acquisition of adult female Cx. quinquefasciatus mosquitoes. This study presents the first systematic identification and analysis of Cx. quinquefasciatus lncRNAs and their association with blood feeding. Results generated from this study will facilitate future investigation on the function of Cx. quinquefasciatus lncRNAs.
During oogenesis, self-renewal and differentiation of germline stem cells (GSCs) must be tightly regulated. The Drosophila female germline serves as an excellent model for studying these regulatory mechanisms. Here, we report that a previously uncharacterized gene CG14545 , which we named sakura , is essential for oogenesis and female fertility in Drosophila . Sakura is predominantly expressed in the ovaries, particularly in the germline cells, including GSCs. sakura null mutant female flies display rudimentary ovaries with germline-less and tumorous phenotypes, fail to produce eggs, and are completely sterile. The germline-specific depletion of sakura impairs Dpp/BMP signaling, leading to aberrant bag-of-marbles ( bam ) expression, resulting in faulty differentiation and loss of GSCs. Additionally, sakura is necessary for normal piwi-interacting RNAs (piRNAs) levels and for proper localization of Oo18 RNA-binding protein (Orb) in developing oocytes. We identified Ovarian Tumor (Otu) as protein binding partner of Sakura, and we found that loss of otu phenocopies loss of sakura in ovaries. Thus, we identified Sakura as a crucial factor for GSC renewal and differentiation and oogenesis, and propose that Sakura and Otu function together in these processes.
Ageing is a phenomenon where the accumulation of all the stresses that alter the functions of living organisms, halter them from maintaining their physiological balance and eventually lead to death. The emergence of epigenetic tremendously contributed to the knowledge of ageing. Epigenetic changes in cells or tissues like deoxyribonucleic acid (DNA) methylation, modification of histone proteins, transcriptional modification and also the involvement of non-coding DNA has been documented to be associated with ageing. In order to study ageing, scientists have taken advantage of several potential organisms to aid them in their study. Drosophila melanogaster has been an essential model in establishing current understanding of the mechanism of ageing as they possess several advantages over other competitors like having homologues to more than 75% of human disease genes, having 50% of Drosophila genes are homologues to human genes and most importantly they are genetically amenable. Here, we would like to summarise the extant knowledge about ageing and epigenetic process and the role of Drosophila as an ideal model to study epigenetics in association with ageing process.
Abstract Aedes albopictus ( Ae. albopictus ) is an important vector of arboviruses such as Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Long noncoding RNA (lncRNAs) have been identified in other vectors including Aedes aegypti and Anopheles mosquitoes, few of which have been implicated in immunity and viral replication. To identify lncRNAs with potential biological functions in Ae. albopictus , we performed RNA-seq on Ae. albopictus cells infected with DENV and ZIKV, and analyzed them together with public datasets. We identified a total of 23,899 transcripts, 16,089 were intergenic while 3,126 and 4,183 of them were antisense and intronic to annotated genes respectively. Ae. albopictus lncRNAs shared many of the characteristics with their invertebrate and vertebrate counterparts, such as low expression, low GC content, short in length, and low conservation even among closely related species. Compared to protein-coding genes, lncRNAs exhibited higher tendency to be expressed in a stage-specific manner. Besides, expression of lncRNAs and nearest protein-coding genes tended to be correlated, especially for the gene pairs within 1kb from each other. We also discovered that Ae. albopictus lncRNAs have the potential to act as precursors for miRNA and piRNAs, both of which have been implicated in antiviral defense in Aedes mosquito. Upon flavivirus infection, lncRNAs were observed to be differentially expressed, which possibly indicates the involvement of lncRNAs in the host-antiviral defense. Our study provides the first systematic identification of lncRNAs in Ae. albopictus , hence, offering a foundation for future studies of lncRNA functions.
Abstract Long noncoding RNAs (lncRNAs) play diverse roles in biological processes. Aedes aegypti ( Ae . aegypti ), a blood-sucking mosquito, is the principal vector responsible for replication and transmission of arboviruses including dengue, Zika, and Chikungunya virus. Systematic identification and developmental characterisation of Ae . aegypti lncRNAs are still limited. We performed genome-wide identification of lncRNAs, followed by developmental profiling of lncRNA in Ae . aegypti . We identified a total of 4,689 novel lncRNA transcripts, of which 2,064, 2,076, and 549 were intergenic, intronic, and antisense respectively. Ae . aegypti lncRNAs share many characteristics with other species including low expression, low GC content, short in length, and low conservation. Besides, the expression of Ae . aegypti lncRNAs tend to be correlated with neighbouring and antisense protein-coding genes. A subset of lncRNAs shows evidence of maternal inheritance; hence, suggesting potential role of lncRNAs in early-stage embryos. Additionally, lncRNAs show higher tendency to be expressed in developmental and temporal specific manner. The results from this study provide foundation for future investigation on the function of Ae . aegypti lncRNAs.
Abstract Viscoelastic properties of sago starch and wheat flour, and sago–wheat flour mixtures at different percentages of sago substitution were studied. Swelling characteristics of high protein wheat (HPW), medium protein wheat (MPW) and low protein wheat (LPW) flour, and sago starch were determined at various temperatures (55°–95°C). Both sago and wheat starch granules started to swell from 55°C and reached a maximum at 75°C. Flour gels containing mixture of sago + wheat of different protein content at different levels of sago substitutions were prepared as follows: sago + HPW, sago + MPW, and sago + LPW flours. Stress relaxation (SR) test for control sago and control wheat flours and sago–wheat mixtures were carried out at different percentages of sago substitutions from 10 to 50%. For control flours the value of asymptotic residue modulus, E A for HPW and MPW was rapidly increased with the increase of the gel concentration up to 30% but it decreased at 20%. For LPW it decreased at 20 and 25%, and increased at 30%. At higher percentage of sago in the mixture, E A value does not show uniform consistence pattern. It was found to increase rapidly at 50% of sago portion for all types of wheat flour.
One of the many strategies that cancer cells evade death is through up-regulation of the BCL-2 anti-apoptotic proteins. Hence, these proteins have become attractive therapeutic targets. Given that different cell populations rely on different anti-apoptotic proteins for survival, it is crucial to determine which proteins are important for Nasopharyngeal carcinoma (NPC) cell survival. Here we determined the survival requirements for the NPC cells using a combination of the CRISPR/Cas9 technique and selective BH3-mimetics. A human apoptosis RT2 Profiler PCR Array was first employed to profile the anti-apoptotic gene expressions in NPC cell lines HK-1 and C666-1. The HK-1 cells expressed all the anti-apoptotic genes (MCL-1, BFL-1, BCL-2, BCL-XL, and BCL-w). Similarly, the C666-1 cells expressed all the anti-apoptotic genes except BFL-1 (undetectable level). Notably, both cell lines highly expressed MCL-1. Deletion of MCL-1 sensitized the NPC cells to BCL-XL selective inhibitor A-1331852, suggesting that MCL-1 and BCL-XL may be important for NPC cell survival. Co-inhibition of MCL-1 and BCL-2 with MCL-1 selective inhibitor S63845 and BCL-2 selective inhibitor ABT-199 inhibited NPC cell proliferation but the effect on cell viability was more profound with co-inhibition of MCL-1 and BCL-XL with S63845 and A-1331852, implying that MCL-1 and BCL-XL are crucial for NPC cell survival. Furthermore, co-inhibition of MCL-1 and BCL-XL inhibited the growth and invasion of NPC spheroids. Deletion of BFL-1 sensitized NPC cells to A-1331852 suggesting that BFL-1 may play a role in NPC cell survival. Taken together co-inhibition of BCL-XL and MCL-1/BFL-1 could be potential treatment strategies for NPC.
In this study, we hypothesized that different strains of Lactobacillus can alleviate hyperlipidemia and liver steatosis via activation of 5′ adenosine monophosphate-activated protein kinase (AMPK), an enzyme that is involved in cellular energy homeostasis, in aged rats. Male rats were fed with a high-fat diet (HFD) and injected with D-galactose daily over 12 weeks to induce aging. Treatments included (n = 6) (i) normal diet (ND), (ii) HFD, (iii) HFD-statin (lovastatin 2 mg/kg/day), (iv) HFD-Lactobacillus fermentum DR9 (10 log CFU/day), (v) HFD-Lactobacillus plantarum DR7 (10 log CFU/day), and (vi) HFD-Lactobacillus reuteri 8513d (10 log CFU/day). Rats administered with statin, DR9, and 8513d reduced serum total cholesterol levels after eight weeks (p < 0.05), while the administration of DR7 reduced serum triglycerides level after 12 weeks (p < 0.05) as compared to the HFD control. A more prominent effect was observed from the administration of DR7, where positive effects were observed, ranging from hepatic gene expressions to liver histology as compared to the control (p < 0.05); downregulation of hepatic lipid synthesis and β-oxidation gene stearoyl-CoA desaturase 1 (SCD1), upregulation of hepatic sterol excretion genes of ATP-binding cassette subfamily G member 5 and 8 (ABCG5 and ABCG8), lesser degree of liver steatosis, and upregulation of hepatic energy metabolisms genes AMPKα1 and AMPKα2. Taken altogether, this study illustrated that the administration of selected Lactobacillus strains led to improved lipid profiles via activation of energy and lipid metabolisms, suggesting the potentials of Lactobacillus as a promising natural intervention for alleviation of cardiovascular and liver diseases.
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