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The anti-exercise-fatigue effect of active peptides derived from fish nicotinamide adenine dinucleotide Dehydrogenase (NADH) was investigated by simulating the hydrolysis of NADH Dehydrogenase protein subunits in five common fish species in China using computer simulations. The oligopeptides obtained through simulated hydrolysis were docked with lactate Dehydrogenase (LDH) and creatine kinase (CK) to identify the oligopeptides with ultra-high affinity for both enzymes (docking fraction ≤ -160), whereas Pymol and Ligplot+ software were used to display and analyze the mechanisms of interaction for molecular docking. The results showed that a total of 72 oligopeptides with ultra-high affinity were obtained from seven different NADH Dehydrogenase protein subunits of five fish species after computer-simulated hydrolysis and molecular docking. There were 36 oligopeptides with ultra-high affinity for LDH and CK, among which the oligopeptide with the highest docking score and the most frequent occurrence was PTIW (-198.762, -204.400). These results establish a theoretical foundation for improving the high-value utilization of fish protein and developing functional foods for anti-exercise-fatigue. [ABSTRACT FROM AUTHOR]

Microbially driven Fe(II) oxidation is vital for Fe-cycling processes. In the present study, a novel strain of nitrate-dependent Fe-oxidizing bacteria (FOB) was isolated from the riparian zone sediment of the Hanjiang River, China. It was identified as Comamonas terrigena strain HJ-2. The strain HJ-2 oxidized 2.80 mmol l−1 Fe(II) within 144 h to form Fe(III)/Fe(II) complex on the cell surface using 1.63 mmol l−1 nitrate as an electron acceptor. The formed nitrite from nitrate reduction chemically oxidized Fe(II). Surprisingly, this strain also reduced nitrilotriacetic iron to form 0.5 mmol l−1 Fe(II) in 120 h in anaerobic conditions primarily mediated by the NADH flavin oxidoreductase. Besides, the strain completely reduced 0.18 mmol l−1 nitrobenzene to aniline in 24 days and 15.6 μmol l−1 arsenate to arsenite in 7 days due to the existence of nitro and arsenate reductases. However, the Fe(II) inhibited the reduction of nitrate, nitrobenzene, and arsenate, possibly due to the impeding of transport of the solutes through the membrane or the synthesis of the related enzymes. These results provide new knowledge about the Fe(II)-cycling and the fate of some pollutants in the riparian zone. It also informed that some bacteria have universal functions on elements and contaminants transformation. [ABSTRACT FROM AUTHOR]

Background: In China, during the cultivation process of Pleurotus ostreatus, the yield and quality of fruiting bodies are easily affected by high temperatures in summer. Nitric oxide (NO) plays an important regulatory role in the response to abiotic stress, and previous studies have found that NO can induce alternative oxidase (aox) experssion in response to heat stress (HS) by regulating aconitase. However, the regulatory pathway of NO is complex, and the function and regulation of the aox gene in the response to HS remain unclear. Results: In this study, we found that NO affected nicotinamide adenine dinucleotide (NADH) and adenosine triphosphate (ATP) levels, reduced hydrogen peroxide (H2O2) and superoxide anion (O2−) contents, and slowed O2− production. Further RNA-Seq results showed that NO regulated the oxidation-reduction process and oxidoreductase activity, affected the cellular respiration pathway and activated aox gene expression. The function of aox was determined by constructing overexpression (OE) and RNA interference (RNAi) strains. The results showed that the OE-aox strains exhibited obviously improved growth recovery after exposure to HS. During exposure to HS, the OE-aox strains exhibited reduced levels of NADH, the product of the tricarboxylic acid (TCA) cycle, and decreased synthesis of ATP, which reduced the production and accumulation of reactive oxygen species (ROS), whereas the RNAi-aox strains exhibited the opposite result. In addition, aox mediated the expression of antioxidant enzyme genes in the mycelia of P. ostreatus under HS through the retrograde signaling pathway. Conclusions: This study shows that the expression of the aox gene in P. ostreatus mycelia can be induced by NO under HS, that it regulates the TCA cycle and cell respiration to reduce the production of ROS, and that it can mediate the retrograde signaling pathway involved in the mycelial response to HS. [ABSTRACT FROM AUTHOR]

The Chinese white pine beetle, Dendroctonus armandi Tsai & Li (Coleoptera: Curculionidae, Scolytinae), is considered the most destructive forest pest in the Qinling and Bashan Mountains of China. In recent years, winter temperature has dropped in these regions, and extremely low temperatures are hard to survive for insects. Cold hardiness becomes a crucial strategy because temperature change often leads to fluctuations in insect abundance, and the metabolism rate is a key index of resistance to cold in overwintering insects. Therefore, we investigated the relationship between the change in respiratory rate and the activity of metabolism‐related mitochondrial enzymes in D. armandi larvae under cold conditions. We found that the respiratory rate decreased, and it was matched with the activity of glutamate dehydrogenase, aconitase, and lipase during overwintering. Among the various test times under cold conditions, the respiratory rate also decreased with decreasing temperature and increased under very low temperatures. At all cold stress periods, glutamate dehydrogenase and lipase showed increased activity at higher temperatures and decreased activity under lower temperatures, but the activity of NAD‐malic enzyme, NADP‐malic enzyme, mitochondrial isocitrate dehydrogenase, and aconitase were contrary. Under all low temperatures, the activity of enzymes – except for NADP‐malic enzyme, glutamate dehydrogenase, and lipase – increased in short‐term cold stress and decreased in long‐term cold stress at 4, 0, −4, −6, −8, and −10 °C. However, at −2 °C, the activity of enzymes showed a decreasing trend in short‐term treatments and an increasing trend in long‐term treatments, except for mitochondrial isocitrate dehydrogenase. The results not only improve our understanding of the metabolic mechanism of cold adaptation in D. armandi, but also provide an important experimental basis for further study and biological pest control. [ABSTRACT FROM AUTHOR]

• Leaf ultrastructure were damaged by 15 and 50 mg L−1 NH 4 +-N. • 15 and 50 mg L−1 NH 4 +-N decreased f v / f m and rETR in submerged leaves of O. cordata. • NH 4 +-N more than 2 mg L−1 reduced the leaf PEPC activity and soluble sugar and starch content. • GS/GOGAT cycle is important in NH 4 +-N assimilation in the submerged leaves of O. cordata. • Ammonium stress might be one possible reason for O. cordata endangerment. Although ammonium (NH 4 +-N) is an important nutrient for plants, increases in soil nitrogen (N) input and atmospheric deposition have made ammonium toxicity a serious ecological problem. In this study, we explored the effects of NH 4 +-N stress on the ultrastructure, photosynthesis, and NH 4 +-N assimilation of Ottelia cordata (Wallich) Dandy, an endangered heteroblastic plant native to China. Results showed that 15 and 50 mg L−1 NH 4 +-N damaged leaf ultrastructure and decreased the values of maximal quantum yield (F v /F m), maximal fluorescence (F m), and relative electron transport rate (rETR) in the submerged leaves of O. cordata. Furthermore, when NH 4 +-N was ≥ 2 mg L−1, phosphoenolpyruvate carboxylase activity (PEPC) and soluble sugar and starch contents decreased significantly. The content of dissolved oxygen in the culture water also decreased significantly. The activity of the NH 4 +-N assimilation enzyme glutamine synthetase (GS) significantly increased when NH 4 +-N was ≥ 10 mg L−1 and NADH-glutamate synthase (NADH-GOGAT) and Fd-glutamate synthase (Fd-GOGAT) increased when NH 4 +-N was at 50 mg L−1. However, the activity of nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase (NADH-GDH) and nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase (NADPH-GDH) did not change, indicating that GS/GOGAT cycle may play an important role in NH 4 +-N assimilation in the submerged leaves of O. cordata. These results show that short-term exposure to a high concentration of NH 4 +-N is toxic to O. cordata. [ABSTRACT FROM AUTHOR]

A new species of Barbastella is described, originally discovered in 2001 in Beijing, northern China. The description of the new species is based on both morphological and molecular data. The morphology of the skull and ears of the new bat is more similar to that of the Egyptian barbastelle (B. leucomelas) and B. barbastellus distributed in Europe than to B. leucomelas found in southern China and Taiwan. Projections and notches occur along the posterior margin of each ear, and a small lobe (vaulted process) protrudes from the middle outer edge of each pinna. The skull and body size of the new species are larger than in B. leucomelas. Echolocation calls were of 2 types, a brief frequency-modulated call that was alternated with longer calls with a convex frequency-time course. The calls were very similar to those of B. barbastellus recorded in Europe, although they may be slightly lower in frequency. Molecular phylogenies were reconstructed from cytochrome-b (Cytb) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) gene sequences. Cladograms of ND1 indicated that barbastelles from the Beijing area form a monophyletic group, which is the sister to B. leucomelas from Egypt. The clade including the new species and Egyptian barbastelle clusters with B. barbastellus, but not with B. leucomelas from Sichuan, Taiwan, and Japan. The genetic distances (corrected Kimura 2-parameter) between Barbastella sp. nov. and most bats from other localities (including all B. barbastellus) were 14.31-17.69% at the ND1 gene and 15.01-17.36% at the Cytb gene. However, ND1 divergence is 12.79% between Barbastella sp. nov. and B. leucomelas from Egypt. All these results support the hypothesis that the barbastelle from Beijing is a new species. Additionally, because Egypt is the type locality of B. leucomelas, the paraphyletic nature of B. leucomelas suggests that barbastelles from Sichuan, Taiwan, and Japan--which are currently classified as B. leucomelas darjelingensis--should not be considered conspecific with B. leucomelas. [ABSTRACT FROM AUTHOR]

Previous epidemiological results show the importance of niacin in relation to the cause of Parkinson's disease, that is the nutritional condition which causes pellagra, niacin deficiency, might protect people from Parkinson's disease. Because maize (Zea mays) contains niacytin which the human being cannot use as niacin, and because maize contains low tryptophan, and abundant leucine which inhibits quinolinate phosphoribosyl transferase, the key enzyme of converting from tryptophan to NAD, niacin deficiency is observed in the people who obtain most of their energy from maize. Correlation coefficients among the prevalence rate of Parkinson's disease, maize yield, niacin intake and selenium intake by each province in China were analyzed. Positive correlation was seen between selenium intake and niacin intake. Niacin deficiency also could be seen in the Keshan disease prevalent area. Negative association was seen between maize production and niacin intake and between maize production and prevalence rate of Parkinson's disease. Retrospective study of preventive effect of maize on mortality from Parkinson's disease in Japan was also demonstrated. Absorbed niacin is used for synthesizing of NAD in the body, and in the metabolic process, NAD releases nicotinamide by poly (ADP-ribosyl) ation which activation has been reported to mediate MPTP-induced Parkinson's disease. Nicotinamide N-methyltransferase (EC2.1.1.1) activity was assayed with cytosolic fraction of rat brain, and nicotinamide could be methylated to 1-methylnicotinamide (MNA) via this enzyme in the brain. The deficiency of mitochondrial NADH: ubiquinone oxidoreductase (complex I) activity is believed to be a critical factor in the development of Parkinson's disease. MNA destroyed several subunits of cerebral complex I, and it was suggested that MNA was concerned in the pathogenesis of Parkinson's disease. From these results, niacin is expected to be the causal substance of Parkinson's disease through following process, NAD produced from niacin releases nicotinamide via poly (ADP-ribosyl) ation which is activated by hydroxyl radical. Released excess nicotinamide is methylated to MNA in cytoplasm, and superoxides formed by MNA via complex I destroys complex I subunits directly or indirectly via mitochondrial DNA damage, and stimulates poly (ADP-ribosyl) ation. Any hereditary or environmental factors may cause acceleration of this rotation and consequently cause neuronal death. [ABSTRACT FROM AUTHOR]