Research Articles (Genetics)
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- ItemFast developing Russian wheat aphid biotypes remains an unsolved enigma(Elsevier Inc., 2020-12-30) Botha, Anna-MariaDiuraphis noxia, commonly known as the Russian wheat aphid, is an economically important cereal pest species, highly invasive and reproduces mostly asexually. Remarkably, many new virulent populations continue to develop, despite the lack of genetic diversity in the aphid. Russian wheat aphid is a phloem feeder and is therefore engaged in a continuous arms battle with its cereal host, with the acquisition of virulence central to the breakdown of host resistance. In the review, most attention is given to recent topics about mechanisms and strategies whereby the aphid acquires virulence against its host, with special reference given to the role of noncoding RNA elements, bacteria, and the epigenetic pathway in possibly directing virulence.
- ItemImproving crops for a changing world(Frontiers Media S.A, 2021-09-06) Lloyd, James Richard; Kossmann, JensPlant biotechnology has been fundamental to the development of human civilisation. The domestication of plants helped increase food production, allowing the sustenance of populations in large settlements and they provide most calories in the human diet alongside being used as fodder for farm animals. They are also good sources of both therapeutic drugs and industrial feed stocks, while more recently they have been used to produce pharmaceutical proteins and biofuels. There are neverthelessmany areas where plants can be improved through geneticmanipulation and there are pressing reasons why this needs to be accomplished.
- ItemPatterns and tempo of PCSK9 pseudogenizations suggest an ancient divergence in mammalian cholesterol homeostasis mechanisms(Springer Nature, 2021-01-30) Van Asch, Barbara; Da Costa, Luís Filipe TeixeiraProprotein convertase subtilisin/kexin type 9 (PCSK9) plays a central role in cholesterol homeostasis in humans as a major regulator of LDLR levels. PCSK9 is an intriguing protease in that it does not act by proteolysis but by preventing LDLR recirculation from endosomes to the plasma membrane. This, and the inexistence of any other proteolytic substrate but itself could suggest that PCSK9 is an exquisite example of evolutionary fine-tuning. However, the gene has been lost in several mammalian species, and null alleles are present (albeit at low frequencies) in some human populations without apparently deleterious health effects, raising the possibility that the PCSK9 may have become dispensable in the mammalian lineage. To address this issue, we systematically recovered, assembled, corrected, annotated and analysed publicly available PCSK9 sequences for 420 eutherian species to determine the distribution, frequencies, mechanisms and timing of PCSK9 pseudogenization events, as well as the evolutionary pressures underlying the preservation or loss of the gene. We found a dramatic difference in the patterns of PCSK9 retention and loss between Euarchontoglires—where there is strong pressure for gene preservation—and Laurasiatheria, where multiple independent events have led to PCSK9 loss in most species. These results suggest that there is a fundamental difference in the regulation of cholesterol metabolism between Euarchontoglires and Laurasiatheria, which in turn has important implications for the use of Laurasiatheria species (e.g. pigs) as animal models of human cholesterol-related diseases.
- ItemUse of pawpaw (Carica papaya) seed in tilapia sex reversal(Reviews in Agricultural Science, 2020-10-18) Omeje, Victor Okonkwo; Lambrechts, Helet; Brink, DanieTilapia breeds effortlessly in captivity, with this attribute which is considered as the “Achilles heel” of the species, because it predisposes pond systems to overcrowding and low weight at harvest. Efforts to mitigate this shortcoming include mono-sex culture using exogenous hormone to reverse the sex of sexually undifferentiated fish. This is premised on the fact that improvement in the growth by mono-sex culture will lead to shortened production times and a more uniform weight at harvest, which will ultimately benefit the producers. However, the use of exogenous hormones in aquaculture has recently raised concerns about the effect on farm workers, consumers and on the environment. Recently research has focused on the use of substances of plants origin which mimic the action of hormones as a potential approach to achieve sex reversal in fish. Pawpaw (Carica papaya) seed contains phytochemicals that hold great promise as a sex reversal and a reproductive inhibition agent in aquaculture. The purpose of this study was to conduct a systematic review of the relevant literature on the possibility of using a less harmful phytochemicals abundant in the plant to effect sex reversal of sexually undifferentiated tilapia.
- ItemDistinct host-immune response toward species related intracellular mycobacterial killing : a transcriptomic study(Taylor & Francis, 2020) Madhvi, Abhilasha; Mishra, Hridesh; Chegoua, Novel N.; Tromp, Gerard; Van Heerden, Carel J.; Pietersen, R. D.; Leisching, Gina; Baker, BienyameenThe comparison of the host immune response when challenged with pathogenic and nonpatho- genic species of mycobacteria can provide answers to the unresolved question of how pathogens subvert or inhibit an effective response. We infected human monocyte derived macrophages (hMDMs) with different species of mycobacteria, in increasing order of pathogenicity, i.e. M. smegmatis, M. bovis BCG, and M. tuberculosis R179 that had been cultured in the absence of detergents. RNA was isolated post-infection and transcriptomic analysis using amplicons (Ampliseq) revealed 274 differentially expressed genes (DEGs) across three species, out of which we selected 19 DEGs for further validation. We used qRT-PCR to confirm the differential expression of 19 DEGs. We studied biological network through Ingenuity Pathway Analysis® (IPA) which revealed up-regulated pathways of the interferon and interleukin family related to the killing of M. smegmatis. Apart from interferon and interleukin family, we found one up-regulated (EIF2AK2) and two down-regulated (MT1A and TRIB3) genes as unique potential targets found by Ampliseq and qRT-PCR which may be involved in the intracellular mycobacterial killing. The roles of these genes have not previously been described in tuberculosis. Multiplex ELISA of culture supernatants showed increased host immune response toward M. smegmatis as compared to M. bovis BCG and M.tb R179. These results enhance our understanding of host immune response against M.tb infection.