Phylogenetic analysis reveals that the use of nicotinamide adenine dinucleotide phosphate (NADP) by prokaryotic isocitrate dehydrogenase (IDH) arose around the time eukaryotic mitochondria first appeared, about 3.5 billion years ago. We replaced the wild-type gene that encodes the NADP-dependent IDH of Escherichia coli with an engineered gene that possesses the ancestral NAD-dependent phenotype. The engineered enzyme is disfavored during competition for acetate. The selection intensifies in genetic backgrounds where other sources of reduced NADP have been removed. A survey of sequenced prokaryotic genomes reveals that those genomes that encode isocitrate lyase, which is essential for growth on acetate, always have an NADP-dependent IDH. Those with only an NAD-dependent IDH never have isocitrate lyase. Hence, the NADP dependence of prokaryotic IDH is an ancient adaptation to anabolic demand for reduced NADP during growth on acetate.
15 October 2020 in Communications Earth & Environment
Antarctic krill, Euphausia superba, supports a valuable commercial fishery in the Southwest Atlantic, which holds the highest krill densities and is warming rapidly. The krill catch is increasing, is concentrated in a small area, and has shifted seasonally from summer to autumn/winter. The fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources, with the main goal of safeguarding the large populations of krill-dependent predators. Here we show that, because of the restricted distribution of successfully spawning krill and high inter-annual variability in their biomass, the risk of direct fishery impacts on the krill stock itself might be higher than previously thought. We show how management benefits could be achieved by incorporating uncertainty surrounding key aspects of krill ecology into management decisions, and how knowledge can be improved in these key areas. This improved information may be supplied, in part, by the fishery itself.
Transmembrane protein 64 (TMEM64), a member of the family of transmembrane protein, is an α-helical membrane protein. Its precise role in various types of tumors, including glioma, is unclear. This study used immunohistochemical (IHC) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques to show that TMEM64 expression was significantly higher in glioma cells and tissues compared to normal cells and tissues, respectively. Additionally, a correlation between high TMEM64 expression and higher grade as well as a worse prognosis was found. TMEM64 enhanced cell proliferation and tumorigenicity while inhibiting glioma cell apoptosis in vitro and in vivo, according to loss- and gain-of-function studies. Mechanistically, it was discovered that TMEM64 increased the malignant phenotype of gliomas by accelerating the translocation of β-catenin from the cytoplasm to the nucleus, thereby activating the Wnt/β-catenin signaling pathway. Stimulation with the Wnt/β-catenin signaling pathway activator CHIR-99021 successfully reversed the malignant phenotype of glioma; however, these effects were inhibited upon TMEM64 silencing. Stimulation with the Wnt/β-catenin signaling pathway inhibitor XAV-939 successfully rescued the malignant phenotype of glioma, which was promoted upon TMEM64 overexpression. Our results provide that TMEM64 as a novel prognostic biomarker and a potential treatment target for glioma.
Rice production in the Anhui province is threatened by fungal diseases. We obtained twenty-five fungal isolates from rice and wild rice leaves showing leaf spot disease collected along the Yangtze River. A phylogenetic analysis based on internal transcribed spacer (ITS), translation elongation factor 1 alpha (TEF1-α), and beta tubulin (TUB2) sequences revealed one isolate (SS-2-JB-1B) grouped with Nigrospora sphaerica, one (QY) with Nigrospora chinensis, twenty-two with Nigrospora oryzae, and one isolate (QY-2) grouped in its own clade, which are related to but clearly different from N. oryzae. Nineteen tested isolates, including sixteen strains from the N. oryzae clade and the three isolates of the other three clades, caused disease on detached rice leaves. The three isolates that did not belong to N. oryzae were also able to cause disease in rice seedlings, suggesting that they were rice pathogens. Isolate QY-2 differed from the other isolates in terms of colony morphology, cell size, and susceptibility to fungicides, indicating that this isolate represents a new species that we named Nigrospora anhuiensis. Our analysis showed that N. sphaerica, N. chinensis, and the new species, N. anhuiensis, can cause rice leaf spot disease in the field. This research provides new knowledge for understanding rice leaf spot disease.
1 November 2020 in Pesticide Biochemistry and Physiology