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61.
62.
Lei Xu Guang-Chao Zhuang Andrew Montgomery Qianyong Liang Samantha B. Joye Fengping Wang 《Environmental microbiology》2021,23(2):641-651
Methane is a potent greenhouse gas; methane production and consumption within seafloor sediments has generated intense interest. Anaerobic oxidation of methane (AOM) and methanogenesis (MOG) primarily occur at the depth of the sulfate–methane transition zone or underlying sediment respectively. Methanogenesis can also occur in the sulfate-reducing sediments through the utilization of non-competitive methylated compounds; however, the occurrence and importance of this process are not fully understood. Here, we combined a variety of data, including geochemical measurements, rate measurements and molecular analyses to demonstrate the presence of a cryptic methane cycle in sulfate-reducing sediments from the continental shelf of the northern South China Sea. The abundance of methanogenic substrates as well as the high MOG rates from methylated compounds indicated that methylotrophic methanogenesis was the dominant methanogenic pathway; this conclusion was further supported by the presence of the methylotrophic genus Methanococcoides. High potential rates of AOM were observed in the sediments, indicating that methane produced in situ could be oxidized simultaneously by AOM, presumably by ANME-2a/b as indicated by 16S rRNA gene analysis. A significant correlation between the relative abundance of methanogens and methanotrophs was observed over sediment depth, indicating that methylotrophic methanogenesis could potentially fuel AOM in this environment. In addition, higher potential rates of AOM than sulfate reduction rates at in situ methane conditions were observed, making alternative electron acceptors important to support AOM in sulfate-reducing sediment. AOM rates were stimulated by the addition of Fe/Mn oxides, suggesting AOM could be partially coupled to metal oxide reduction. These results suggest that methyl-compounds driven methane production drives a cryptic methane cycling and fuels AOM coupled to the reduction of sulfate and other electron acceptors. 相似文献
63.
Baohua Wang Xavier Draye Zhimin Zhuang Zhengsheng Zhang Min Liu Edward L. Lubbers Don Jones O. Lloyd May Andrew H. Paterson Peng W. Chee 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2017,130(6):1297-1308
Key message
QTLs for fiber length mapped in three generations of advanced backcross populations derived from crossing Gossypium hirsutum and Gossypium mustelinum showed opportunities to improve elite cottons by introgression from wild relatives.Abstract
The molecular basis of cotton fiber length in crosses between Gossypium hirsutum and Gossypium mustelinum was dissected using 21 BC3F2 and 12 corresponding BC3F2:3 and BC3F2:4 families. Sixty-five quantitative trait loci (QTLs) were detected by one-way analysis of variance. The QTL numbers detected for upper-half mean length (UHM), fiber uniformity index (UI), and short fiber content (SFC) were 19, 20, and 26 respectively. Twenty-three of the 65 QTLs could be detected at least twice near adjacent markers in the same family or near the same markers across different families/generations, and 32 QTLs were detected in both one-way variance analyses and mixed model-based composite interval mapping. G. mustelinum alleles increased UHM and UI and decreased SFC for five, one, and one QTLs, respectively. In addition to the main-effect QTLs, 17 epistatic QTLs were detected which helped to elucidate the genetic basis of cotton fiber length. Significant among-family genotypic effects were detected at 18, 16, and 16 loci for UHM, UI, and SFC, respectively. Six, two, and two loci showed genotype?×?family interaction for UHM, UI and SFC, respectively, illustrating complexities that might be faced in introgression of exotic germplasm into cultivated cotton. Co-location of many QTLs for UHM, UI, and SFC accounted for correlations among these traits, and selection of these QTLs may improve the three traits simultaneously. The simple sequence repeat (SSR) markers associated with G. mustelinum QTLs will assist breeders in transferring and maintaining valuable traits from this exotic source during cultivar development.64.
Kun-Tai Li Dong-Hong Liu Ying-Ping Zhuang Yong-Hong Wang Ju Chu Si-Liang Zhang 《World journal of microbiology & biotechnology》2008,24(11):2525-2530
Previous research has confirmed that cobalt ion and dimethylbenzimidazole (DMBI) are the precursors of vitamin B12 biosynthesis, and porphobilinogen synthase (PBG synthase) is a zinc-requiring enzyme. In this paper, the effects of Zn2+, Co2+ and DMBI on vitamin B12 production by Pseudomonas denitrificans in shake flasks were studied. Present experimental results demonstrated that the addition of the above mentioned three components
to the fermentation medium could significantly stimulate the biosynthesis of vitamin B12. The concentrations of zinc sulphate, cobaltous chloride and DMBI in the fermentation medium were further optimized with
rotatable orthogonal central composite design and statistical analysis by Data Processing System (DPS) software. As a result,
vitamin B12 production was increased from 69.36 ± 0.66 to 78.23 ± 0.92 μg/ml. 相似文献
65.
66.
多倍化是植物物种进化的主要动力, 异源多倍体植物在形成早期发生着快速的基因表达变化。本文概述了异源多倍体植物中基因表达变化的特点, 包括基因的沉默、激活和部分同源基因表达水平的变化, 探讨了基因表达变化的分子机制和生物学意义, 并对研究中的问题进行了分析和展望。 相似文献
67.
68.
Purpose
It remains controversial whether mini-incision (MI) benefits patients in total hip arthroplasty (THA). We performed a meta-analysis of randomized controlled trials (RCTs) to assess the effects of MI on surgical and functional outcomes in THA patients.Methods
A systematic electronic literature search (up to May 2013) was conducted to identify RCTs comparing MI with standard incision (SI) THA. The primary outcome measures were surgical and functional outcomes. According to the surgical approach taken, MI THA patients were divided into four subgroups for sub-group meta-analysis. Standardized mean differences (SMDs) or risk differences (RDs) with accompanying 95% confidence intervals (CIs) were calculated and pooled using a fixed-effect or random-effect model according to the heterogeneity.Results
A total of 14 RCTs involving THA 1,174 patients met the inclusion criteria. The trials were medium risk of bias. The overall meta-analysis showed MI THA reduced total blood loss (95% CI, -201.83 to -21.18; p=.02) and length of hospital stay ( 95% CI, -0.67 to -0.08; p=.01) with significant heterogeneity. However, subgroup meta-analysis revealed posterior MI THA had perioperative advantages of reduced surgical duration ( 95% CI, -8.45 to -2.67; P<.001), less blood loss ( 95% CI, -107.20 to -1.73; P=.04) and shorter hospital stay ( 95% CI, -0.74 to -0.06; p=.002) with low heterogeneity. There were no significant differences between MI and SI THA groups in term of pain medication dose, functional outcome (HHS), radiological outcome or complications (P>.05, respectively).Conclusions
Although no definite overall conclusion can be arrived at on whether MI THA is superior to SI THA, posterior MI THA clearly result in a significant decrease in surgical duration, blood loss and hospital stay. It seems to be a safe minimally invasive surgical procedure without increasing the risk of component malposition or complications. 相似文献69.
Zhuang J Gutknecht R Flükiger K Hasler L Erni B Engel A 《Archives of biochemistry and biophysics》1999,372(1):89-96
The glucose transporter of the bacterial phosphotransferase system mediates sugar transport across the cytoplasmic membrane concomitant with sugar phosphorylation. It consists of a cytoplasmic subunit IIA(Glc) and the transmembrane subunit IICB(Glc). IICB(Glc) was purified to homogeneity by urea/alkali washing of membranes and nickel-chelate affinity chromatography. About 1.5 mg highly pure IICB(Glc) representing 77% of the total activity present in the membranes was obtained from 8g (wet weight) of cells. IICB(Glc) was reconstituted into lipid bilayers by temperature-controlled dialysis to yield small 2D crystals and by a rapid detergent-dilution procedure to yield densely packed vesicles. Electron microscopy and digital image processing of the negatively stained 2D crystals revealed a trigonal lattice with a unit cell size of a = b = 14.5 nm. The unit cell morphology exhibited three dimers of IICB(Glc) surrounding the threefold symmetry center. Single particle analysis of IICB(Glc) in proteoliposomes obtained by detergent dialysis also showed predominantly dimeric structures. 相似文献