CTP synthase: the hissing of the cellular serpent.

CTP biosynthesis is carried out by two pathways: salvage and de novo. CTPsyn catalyzes the latter. The study of CTPsyn activity in mammalian cells began in the 1970s, and various fascinating discoveries were made regarding the role of CTPsyn in cancer and development. However, its ability to fit into a cellular serpent-like structure, termed 'cytoophidia,' was only discovered a decade ago by three independent groups of scientists. Although the self-assembly of CTPsyn into a filamentous structure is evolutionarily conserved, the enzyme activity upon this self-assembly varies in different species. CTPsyn is required for cellular development and homeostasis. Changes in the expression of CTPsyn cause developmental changes in Drosophila melanogaster. A high level of CTPsyn activity and formation of cytoophidia are often observed in rapidly proliferating cells such as in stem and cancer cells. Meanwhile, the deficiency of CTPsyn causes severe immunodeficiency leading to immunocompromised diseases caused by bacteria, viruses, and parasites, making CTPsyn an attractive therapeutic target. Here, we provide an overview of the role of CTPsyn in cellular and disease perspectives along with its potential as a drug target.

Genome-wide identification and characterization of long intergenic noncoding RNAs in the regenerative flatworm Macrostomum lignano.

The free-living flatworm Macrostoma lignano (M. lignano) is an emerging model organism for aging and regeneration research. Long intergenic non-coding RNAs (lincRNAs) have important roles in many biological processes such as aging, stem cell maintenance and differentiation. However, to date, there is no systematic identification of lincRNAs in M. lignano. By using public RNA-seq data, we identified a total of 2547 lincRNA transcripts in M. lignano genome. We discovered that M. lignano lincRNAs shared many characteristics with other species such as shorter in length, lower GC content, and lower in expression compared to protein-coding genes. Unlike protein-coding genes, M. lignano lincRNAs showed higher tendency to be expressed in temporal and region-specific fashion. Additionally, co-expression network analysis and functional enrichment suggest that M. lignano lincRNAs have potential roles in regeneration. This study will provide important resources and pave the way for investigations on non-coding genes involved in aging and regeneration.

MicroRNA regulation of CTP synthase and cytoophidium in Drosophila melanogaster.

CTPsyn is a crucial metabolic enzyme which synthesizes CTP nucleotides. It has the extraordinary ability to compartmentalize into filaments termed cytoophidia. Though the structure is evolutionarily conserved across kingdoms, the mechanisms behind their formation remain unknown. MicroRNAs (miRNAs) are short single-stranded RNA capable of directing mRNA silencing and degradation. D. melanogaster has a high total gene count to miRNA gene number ratio, alluding to the possibility that CTPsyn too may come under their regulation. A thorough miRNA overexpression involving 123 miRNAs was conducted, followed by CTPsyn-specific staining upon cytoophidia-rich egg chambers. This revealed a small group of candidates which confer either a lengthening or truncating effect on cytoophidia, suggesting they may play a role in regulating CTPsyn. MiR-975 and miR-1014 are both cytoophidia-elongating, whereas miR-190 and miR-932 are cytoophidia-shortening. Though target prediction shows that miR-975 and miR-932 do indeed have binding sites on CTPsyn mRNA, in vitro assays instead revealed a low probability of this being true, instead indicating that the effects asserted by overexpressed miRNAs indirectly reach CTPsyn and its cytoophidia through the actions of middling elements. In silico target prediction and qPCR quantification indicated that, at least for miR-932 and miR-1014, these undetermined elements may be players in fat metabolism. This is the first study to thoroughly investigate miRNAs in connection to CTPsyn expression and activity in any species. The findings presented could serve as a basis for further queries into not only the fundamental aspects of the enzyme's regulation, but may uncover new facets of closely related pathways as well.

Lactobacillus Strains Alleviated Hyperlipidemia and Liver Steatosis in Aging Rats via Activation of AMPK.

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 ß-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.

Ageing, Drosophila melanogaster and Epigenetics.

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.

Lactobacillus sp. improved microbiota and metabolite profiles of aging rats.

Aging is closely associated with altered gut function and composition, in which elderly were reported with reduced gut microbiota diversity and increased incidence of age-related diseases. Probiotics have been shown to exert beneficial health-promoting effects through modulation of intestinal microflora biodiversity, thus the effects of probiotics administration on D-galactose (D-gal) senescence-induced rat were evaluated based on the changes in gut microbiota and metabolomic profiles. Upon senescence induction, the ratio of Firmicutes/ Bacteroidetes was significantly lowered, while treatment with Lactobacillus helveticus OFS 1515 and L. fermentum DR9 increased the ratio at the phylum level (P < 0.05). Study on the genus level showed that L. paracasei OFS 0291 and L. helveticus OFS 1515 administration reduced Bacteroides, which are prominently opportunistic pathogens while L. fermentum DR9 treated rats promoted the proliferation of Lactobacillus compared to the aged rats (P < 0.05). Probiotics treatment did not alter fecal short-chain fatty acid (SCFA) profile, but an increase in acetate was observed in the D-gal rats. The analysis of fecal water-soluble metabolites showed that D-gal induced senescence caused great impact on amino acids metabolism such as urocanic acid, citrulline, cystamine and 5-oxoproline, which could serve as potential aging biomarkers. Treatment with probiotics ameliorated these metabolites in a strain-specific manner, whereby L. fermentum DR9 promoted antioxidative effect through upregulation of oxoproline, whereas both L. paracasei OFS 0291 and L. helveticus OFS 1515 restored the levels of reducing sugars, arabinose and ribose similar to the young rats. D-gal induced senescence did cause significant immunological alteration in the colon of aged rats however, all probiotic strains demonstrated immunomodulatory properties as L. paracasei OFS 0291, L. helveticus OFS 1515 and L. fermentum DR9 alleviated proinflammatory cytokines TNF-α, IFN-γ and IL-1ß as well as IL-4 compared to the aged control (P < 0.05). Our study highlights the potential of probiotics as an anti-aging therapy through healthy gut modulation.

CTP synthase knockdown during early development distorts the nascent vertebral column and causes fluid retention in multiple tissues in zebrafish.

CTP Synthase (CTPS) is a metabolic enzyme that is recognized as a catalyst for nucleotide, phospholipid and sialoglycoprotein production. Though the structural characteristics and regulatory mechanisms of CTPS are well-understood, little is known regarding the extent of its involvement during the early developmental stages of vertebrates. Zebrafish carries two CTPS genes, annotated as ctps1a and ctps1b. Phylogenetic analyses show that both genes had diverged from homologues in the ancestral Actinopterygii, Oreochromis niloticus. Conservation of common CTPS-catalytic regions further establishes that both proteins are likely to be functionally similar to hsaCTPS. Here, we show that ctps1a is more critical throughout the initial period of embryonic development than ctps1b. The effects of concurrent partial knockdown are dependent on ctps1a vs ctps1b dosage ratios. When these are equally attenuated, abnormal phenotypes acquired prior to the pharyngula period disappear in hatchlings (48hpf); however, if either gene is more attenuated than the other, these only become more pronounced in advanced stages. Generally, disruption to normal ctps1a or ctps1b expression levels by morpholinos culminates in the distortion of the early spinal column as well as multiple-tissue oedema. Other effects include slower growth rates, increased mortality rates and impaired structural formation of the young fish's extremities. Embryos grown in DON, a glutamine-analogue drug and CTPS antagonist, also exhibit similar characteristics, thus strengthening the validity of the morpholino-induced phenotypes observed. Together, our results demonstrate the importance of CTPS for the development of zebrafish embryos, as well as a disparity in activity and overall importance amongst isozymes.

Drosophila melanogaster: Deciphering Alzheimer's Disease.

Alzheimer's disease (AD) is the most widespread neurodegenerative disorder worldwide. Its pathogenesis involves two hallmarks: aggregation of amyloid beta (Aß) and occurrence of neurofibrillary tangles (NFTs). The mechanism behind the disease is still unknown. This has prompted the use of animal models to mirror the disease. The fruit fly, Drosophila melanogaster has garnered considerable attention as an organism to recapitulate human disorders. With the ability to monopolise a multitude of traditional and novel genetic tools, Drosophila is ideal for studying not only cellular aspects but also physiological and behavioural traits of human neurodegenerative diseases. Here, we discuss the use of the Drosophila model in understanding AD pathology and the insights gained in discovering drug therapies for AD.

Only one isoform of Drosophila melanogaster CTP synthase forms the cytoophidium.

CTP synthase is an essential enzyme that plays a key role in energy metabolism. Several independent studies have demonstrated that CTP synthase can form an evolutionarily conserved subcellular structure termed cytoophidium. In budding yeast, there are two isoforms of CTP synthase and both isoforms localize in cytoophidium. However, little is known about the distribution of CTP synthase isoforms in Drosophila melanogaster. Here, we report that three transcripts generated at the CTP synthase gene locus exhibit different expression profiles, and three isoforms encoded by this gene locus show a distinct subcellular distribution. While isoform A localizes in the nucleus, isoform B distributes diffusely in the cytoplasm, and only isoform C forms the cytoophidium. In the two isoform C-specific mutants, cytoophidia disappear in the germline cells. Although isoform A does not localize to the cytoophidium, a mutation disrupting mostly isoform A expression results in the disassembly of cytoophidia. Overexpression of isoform C can induce the growth of the cytoophidium in a cell-autonomous manner. Ectopic expression of the cytoophidium-forming isoform does not cause any defect in the embryos. In addition, we identify that a small segment at the amino terminus of isoform C is necessary but not sufficient for cytoophidium formation. Finally, we demonstrate that an excess of the synthetase domain of CTP synthase disrupts cytoophidium formation. Thus, the study of multiple isoforms of CTP synthase in Drosophila provides a good opportunity to dissect the biogenesis and function of the cytoophidum in a genetically tractable organism.

Drosophila Argonaute 1 and its miRNA biogenesis partners are required for oocyte formation and germline cell division.

Argonaute 1 (Ago1) is a member of the Argonaute/PIWI protein family involved in small RNA-mediated gene regulation. In Drosophila, Ago1 plays a specific role in microRNA (miRNA) biogenesis and function. Previous studies have demonstrated that Ago1 regulates the fate of germline stem cells. However, the function of Ago1 in other aspects of oogenesis is still elusive. Here we report the function of Ago1 in developing egg chambers. We find that Ago1 protein is enriched in the oocytes and is also highly expressed in the cytoplasm of follicle cells. Clonal analysis of multiple ago1 mutant alleles shows that many mutant egg chambers contain only 8 nurse cells without an oocyte which is phenocopied in dicer-1, pasha and drosha mutants. Our results suggest that Ago1 and its miRNA biogenesis partners play a role in oocyte determination and germline cell division in Drosophila.

Developmental RNA processing of 3'UTRs in Hox mRNAs as a context-dependent mechanism modulating visibility to microRNAs.

The Drosophila Hox gene Ultrabithorax (Ubx) controls the development of thoracic and abdominal segments, allocating segment-specific features to different cell lineages. Recent studies have shown that Ubx expression is post-transcriptionally regulated by two microRNAs (miRNAs), miR-iab4 and miR-iab8, acting on target sites located in the 3' untranslated regions (UTRs) of Ubx mRNAs. Here, we show that during embryonic development Ubx produces mRNAs with variable 3'UTRs in different regions of the embryo. Analysis of the resulting remodelled 3'UTRs shows that each species harbours different sets of miRNA target sites, converting each class of Ubx mRNA into a considerably different substrate for miRNA regulation. Furthermore, we show that the distinct developmental distributions of Ubx 3'UTRs are established by a mechanism that is independent of miRNA regulation and therefore are not the consequence of miR-iab4/8-mediated RNA degradation acting on those sensitive mRNA species; instead, we propose that this is a hard-wired 3'UTR processing system that is able to regulate target mRNA visibility to miRNAs according to developmental context. We show that reporter constructs that include Ubx short and long 3'UTR sequences display differential expression within the embryonic central nervous system, and also demonstrate that mRNAs of three other Hox genes suffer similar and synchronous developmental 3'UTR processing events during embryogenesis. Our work thus reveals that developmental RNA processing of 3'UTR sequences is a general molecular strategy used by a key family of developmental regulators so that their transcripts can display different levels of visibility to miRNA regulation according to developmental cues.

p-Coumaric acid attenuates the effects of Aß42 in vitro and in a Drosophila Alzheimer's disease model.

Alzheimer's disease (AD) is the most common neurodegenerative condition in civilizations worldwide. The distinctive occurrence of amyloid-beta (Aß) accumulation into insoluble fibrils is part of the disease pathophysiology with Aß42 being the most toxic and aggressive Aß species. The polyphenol, p-Coumaric acid (pCA), has been known to boost a number of therapeutic benefits. Here, pCA's potential to counteract the negative effects of Aß42 was investigated. First, pCA was confirmed to reduce Aß42 fibrillation using an in vitro activity assay. The compound was next examined on Aß42-exposed PC12 neuronal cells and was found to significantly decrease Aß42-induced cell mortality. pCA was then examined using an AD Drosophila melanogaster model. Feeding of pCA partially reversed the rough eye phenotype, significantly lengthened AD Drosophila's lifespan, and significantly enhanced the majority of the AD Drosophila's mobility in a sex-dependent manner. The findings of this study suggest that pCA may have therapeutic benefits for AD.

Behavioural Effects and RNA-seq Analysis of Aß42-Mediated Toxicity in a Drosophila Alzheimer's Disease Model.

Alzheimer's disease (AD) is the most common neurological ailment worldwide. Its process comprises the unique aggregation of extracellular senile plaques composed of amyloid-beta (Aß) in the brain. Aß42 is the most neurotoxic and aggressive of the Aß42 isomers released in the brain. Despite much research on AD, the complete pathophysiology of this disease remains unknown. Technical and ethical constraints place limits on experiments utilizing human subjects. Thus, animal models were used to replicate human diseases. The Drosophila melanogaster is an excellent model for studying both physiological and behavioural aspects of human neurodegenerative illnesses. Here, the negative effects of Aß42-expression on a Drosophila AD model were investigated through three behavioural assays followed by RNA-seq. The RNA-seq data was verified using qPCR. AD Drosophila expressing human Aß42 exhibited degenerated eye structures, shortened lifespan, and declined mobility function compared to the wild-type Control. RNA-seq revealed 1496 genes that were differentially expressed from the Aß42-expressing samples against the control. Among the pathways that were identified from the differentially expressed genes include carbon metabolism, oxidative phosphorylation, antimicrobial peptides, and longevity-regulating pathways. While AD is a complicated neurological condition whose aetiology is influenced by a number of factors, it is hoped that the current data will be sufficient to give a general picture of how Aß42 influences the disease pathology. The discovery of molecular connections from the current Drosophila AD model offers fresh perspectives on the usage of this Drosophila which could aid in the discovery of new anti-AD medications.

Uncovering the Microbiota of Bagworm Metisa plana (Lepidoptera: Psychidae) in Oil Palm Plantations in Malaysia.

Bagworm Metisa plana is one of the major pests in Malaysia's oil palm plantation, with infestation resulting in huge economical loss. Currently, the microbial profile of the bagworm has yet to be study. Understanding the biology of the pest such as the bacterial community is crucial as bacteria associated with insects often provide benefits to the insect, giving the insect host a better chance of survival. Here, 16S amplicon sequencing was used to identify the bacteria community of M. plana. Additionally, two comparisons were made, the bacterial communities between two larval stages (early instar stage and late instar stage) from outbreak area; the bacterial communities of late instar stage larvae from non-outbreak between outbreak areas. From this study, it was found that the bacterial community of M. plana consisted of Proteobacteria, Actinobacteria, Bacterioidetes, Firmicutes and other minor phyla, with Proteobacteria being the most dominant phylum. Furthermore, bacterial genera of M. plana consisted of Pantoea, Curtobacterium, Pseudomonas, Massilia and other minor genera, with Pantoea being the most dominant. It was also found that the alpha and beta diversity in both comparisons were not significantly different. We present our data as a first insight towards the bacterial community of M. plana, paving a way towards understanding the biology of the bagworm M. plana.

Metisa plana adalah salah satu daripada perosak utama dalam ladang kelapa sawit Malaysia, dengan serangan yang mengakibatkan kerugian besar kepada ekonomi. Pada masa ini, profil mikrob bagworm masih belum dikaji. Memahami biologi perosak seperti komuniti bakteria adalah penting kerana bakteria yang dikaitkan dengan serangga sering memberi manfaat kepada serangga, memberikan hos serangga peluang untuk terus hidup. Penjujukan amplikon 16S digunakan untuk mengenal pasti komuniti bakteria M. plana. Selain itu, dua perbandingan telah dibuat, komuniti bakteria antara dua peringkat larva (peringkat instar awal dan peringkat instar lewat) dari kawasan wabak; komuniti bakteria larva peringkat instar lewat dari kawasan bukan wabak dan kawasan wabak. Daripada kajian ini, didapati komuniti bakteria M. plana terdiri daripada Proteobacteria, Actinobacteria, Bacterioidetes, Firmicutes dan filum kecil lain, dengan Proteobacteria merupakan filum yang paling dominan. Tambahan pula, genera bakteria M. plana terdiri daripada Pantoea, Curtobacterium, Pseudomonas, Massilia dan genera minor lain, dengan Pantoea yang paling dominan. Kajian ini juga mendapati bahawa kepelbagaian alfa dan beta dalam kedua-dua perbandingan adalah tidak jauh berbeza. Data ini dibentangkan sebagai pandangan pertama terhadap komuniti bakteria M. plana, membuka jalan ke arah memahami biologi bagworm M. plana.

3-[[(3S)-1,2,3,4-Tetrahydroisoquinoline-3-Carbonyl]Amino]Propanoic Acid (THICAPA) Is Protective Against Aß42-Induced Toxicity In Vitro and in an Alzheimer's Disease Drosophila.

Alzheimer's disease (AD) is the most prevalent type of dementia globally. The accumulation of amyloid-beta (Aß) extracellular senile plaques in the brain is one of the hallmark mechanisms found in AD. Aß42 is the most damaging and aggressively aggregating Aß isomer produced in the brain. Although Aß42 has been extensively researched as a crucial peptide connected to the development of the characteristic amyloid fibrils in AD, the specifics of its pathophysiology are still unknown. Therefore, the main objective was to identify novel compounds that could potentially mitigate the negative effects of Aß42. 3-[[(3S)-1,2,3,4-Tetrahydroisoquinoline-3-carbonyl]amino]propanoic acid (THICAPA) was identified as a ligand for Aß42 and for reducing fibrillary Aß42 aggregation. THICAPA also improved cell viability when administered to PC12 neuronal cells that were exposed to Aß42. Additionally, this compound diminished Aß42 toxicity in the current AD Drosophila model by rescuing the rough eye phenotype, prolonging the life span, and enhancing motor functions. Through next-generation RNA-sequencing, immune response pathways were downregulated in response to THICAPA treatment. Thus, this study suggests THICAPA as a possible disease-modifying treatment for AD.

Revised Annotation and Characterization of Novel Aedes albopictus miRNAs and Their Potential Functions in Dengue Virus Infection.

The Asian tiger mosquito, Ae. albopictus, is a highly invasive species that transmits several arboviruses including dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV). Although several studies have identified microRNAs (miRNAs) in Ae. albopictus, it is crucial to extend and improve current annotations with both the newly improved genome assembly and the increased number of small RNA-sequencing data. We combined our high-depth sequence data and 26 public datasets to re-annotate Ae. albopictus miRNAs and found a total of 72 novel mature miRNAs. We discovered that the expression of novel miRNAs was lower than known miRNAs. Furthermore, compared to known miRNAs, novel miRNAs are prone to expression in a stage-specific manner. Upon DENV infection, a total of 44 novel miRNAs were differentially expressed, and target prediction analysis revealed that miRNA-target genes were involved in lipid metabolism and protein processing in endoplasmic reticulum. Taken together, the miRNA annotation profile provided here is the most comprehensive to date. We believed that this would facilitate future research in understanding virus-host interactions, particularly in the role of miRNAs.

Dual inhibition of anti-apoptotic proteins BCL-XL and MCL-1 enhances cytotoxicity of Nasopharyngeal carcinoma cells.

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.

A transcriptomic (RNA-seq) analysis of Drosophila melanogaster adult testes overexpressing microRNA-2b-1.

MicroRNAs (miRNAs) are short non-coding single-stranded RNAs with approximately 22 nucleotides in length that negatively regulate the mRNA translation of a target gene. MiR-2b-1 belongs to the largest miR-2 family in Drosophila melanogaster with 8 members and this miRNA family is conserved in invertebrates. miRNAs play key roles in gene regulation, cell proliferation, cell death, cell differentiation and cell developmental homeostasis in multicellular organisms. Its role in various human diseases is continuously being studied. miRNAs also found out to be crucial in maintaining stem cell niche in D. melanogaster gonads. We have identified that ectopic overexpression of miR-2b-1 of D. melanogaster causes testicular bulging (a tumour like phenotype) in 3-5 days old adult flies. Hence, we have performed a transcriptomic (RNA-seq) analysis to understand the role of miR-2b-1 in the development, maintenance, and differentiation of D. melanogaster adult testis stem cells. Data are available from GEO (accession number GSE211399).

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G.

BACKGROUND: Improved understanding of the molecular basis of insecticide resistance may yield new opportunities for control of relevant disease vectors. In this current study, we investigated the quantification responses for the phenotypic and genotypic resistance of Aedes aegypti populations from different states in Malaysia. METHODS: We tested the insecticide susceptibility status of adult Ae. aegypti from populations of three states, Penang, Selangor and Kelantan (Peninsular Malaysia), against 0.25% permethrin and 0.25% pirimiphos-methyl using the World Health Organisation (WHO) adult bioassay method. Permethrin-resistant and -susceptible samples were then genotyped for domains II and III in the voltage-gated sodium channel (vgsc) gene using allele-specific polymerase chain reaction (AS-PCR) for the presence of any diagnostic single-nucleotide mutations. To validate AS-PCR results and to identify any possible additional point mutations, these two domains were sequenced. RESULTS: The bioassays revealed that populations of Ae. aegypti from these three states were highly resistant towards 0.25% permethrin and 0.25% pirimiphos-methyl. Genotyping results showed that three knockdown (kdr) mutations (S989P, V1016G and F1534C) were associated with pyrethroid resistance within these populations. The presence of a novel mutation, the A1007G mutation, was also detected. CONCLUSIONS: This study revealed the high resistance level of Malaysian populations of Ae. aegypti to currently used insecticides. The resistance could be due to the widespread presence of four kdr mutations in the field and this could potentially impact the vector control programmes in Malaysia and alternative solutions should be sought.

SARS-CoV-2 genomic surveillance in Malaysia: displacement of B.1.617.2 with AY lineages as the dominant Delta variants and the introduction of Omicron during the fourth epidemic wave.

OBJECTIVES: This study reported SARS-CoV-2 whole genome sequencing results from June 2021 to January 2022 from seven genome sequencing centers in Malaysia as part of the national surveillance program. METHODS: COVID-19 samples that tested positive by reverse transcription polymerase chain reaction and with cycle threshold values <30 were obtained throughout Malaysia. Sequencing of SARS-CoV-2 complete genomes was performed using Illumina, Oxford Nanopore, or Ion Torrent platforms. A total of 6163 SARS-CoV-2 complete genome sequences were generated over the surveillance period. All sequences were submitted to the Global Initiative on Sharing All Influenza Data database. RESULTS: From June 2021 to January 2022, Malaysia experienced the fourth wave of COVID-19 dominated by the Delta variant of concern, including the original B.1.617.2 lineage and descendant AY lineages. The B.1.617.2 lineage was identified as the early dominant circulating strain throughout the country but over time, was displaced by AY.59 and AY.79 lineages in Peninsular (west) Malaysia, and the AY.23 lineage in east Malaysia. In December 2021, pilgrims returning from Saudi Arabia facilitated the introduction and spread of the BA.1 lineage (Omicron variant of concern) in the country. CONCLUSION: The changing trends of circulating SARS-CoV-2 lineages were identified, with differences observed between west and east Malaysia. This initiative highlighted the importance of leveraging research expertise in the country to facilitate pandemic response and preparedness.