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131.
Ni-Ni Guo Zong-Ming Zheng Yu-Lin Mai Hong-Juan Liu De-Hua Liu 《Applied microbiology and biotechnology》2010,86(2):701-707
The filtration in 1,3-propanediol (1,3-PD) downstream process is influenced by the large amounts of capsular polysaccharides
(CPS) produced by Klebsiella pneumoniae CGMCC 1.6366. The morphological and fermentation properties were investigated with the CPS-deficient mutant K. pneumoniae CGMCC 1.6366 CPS. Similar biomass was obtained with CGMCC 1.6366, and the mutant strain in batch cultures indicating the
cell growth was slightly inhibited by CPS defection. The viscosity of fermentation broth by mutant strain decreased by 27.45%.
The flux with ceramic membrane filter was enhanced from 168.12 to 303.6 l h−1 m−2, exhibiting the great importance for downstream processing of 1,3-PD fermentation. The products spectrum of mutant isolate
changed remarkably regarding to the concentration of fermentation products. The synthesis of important 1,3-PD and 2,3-butanediol
was enhanced from 9.73 and 4.06 g l−1 to 10.37 and 4.77 g l−1 in batch cultures. The noncapsuled K. pneumoniae provided higher 1,3-PD yield of 0.54 mol mol−1 than that of encapsuled wild parent in batch cultures. The fed-batch fermentation of mutant strain resulted in 1,3-PD concentration,
yield, and productivity of 78.13 g l−1, 0.53 mol mol−1, and 1.95 g l−1 h−1, respectively. 相似文献
132.
In addition to mitochondria, BCL‐2 is located at the endoplasmic reticulum (ER) where it is a constituent of several distinct complexes. Here, we identify the BCL‐2‐interacting protein at the ER, nutrient‐deprivation autophagy factor‐1 (NAF‐1)—a bitopic integral membrane protein whose defective expression underlies the aetiology of the neurodegenerative disorder Wolfram syndrome 2 (WFS2). NAF‐1 contains a two iron–two sulphur coordinating domain within its cytosolic region, which is necessary, but not sufficient for interaction with BCL‐2. NAF‐1 is displaced from BCL‐2 by the ER‐restricted BH3‐only protein BIK and contributes to regulation of BIK‐initiated autophagy, but not BIK‐dependent activation of caspases. Similar to BCL‐2, NAF‐1 is found in association with the inositol 1,4,5‐triphosphate receptor and is required for BCL‐2‐mediated depression of ER Ca2+ stores. During nutrient deprivation as a physiological stimulus of autophagy, BCL‐2 is known to function through inhibition of the autophagy effector and tumour suppressor Beclin 1. NAF‐1 is required in this pathway for BCL‐2 at the ER to functionally antagonize Beclin 1‐dependent autophagy. Thus, NAF‐1 is a BCL‐2‐associated co‐factor that targets BCL‐2 for antagonism of the autophagy pathway at the ER. 相似文献
133.
Lu Y Jin X Chen Y Li S Yuan Y Mai G Tian B Long D Zhang J Zeng L Li Y Cheng J 《Cell biochemistry and function》2010,28(8):637-643
Hypoxia/reoxygenation (H/R)‐induced injury is the key factor associated with islet graft dysfunction. This study aims to examine the effect of mesenchymal stem cells (MSCs) on islet survival and insulin secretion under H/R conditions. Islets from rats were isolated, purified, cultured with or without MSCs, and exposed to hypoxia (O2 ≤ 1%) for 8 h and reoxygenation for 24 and 48 h, respectively. Islet function was evaluated by measuring basal and glucose‐stimulated insulin secretion (GSIS). Apoptotic islet cells were quantified using Annexin V‐FITC. Anti‐apoptotic effects were confirmed by mRNA expression analysis of hypoxia‐resistant molecules, HIF‐1α, HO‐1, and COX‐2, using semi‐quantitative retrieval polymerase chain reaction (RT‐PCR). Insulin expression in the implanted islets was detected by immunohistological analysis. The main results show that the stimulation index (SI) of GSIS was maintained at higher levels in islets co‐cultured with MSCs. The MSCs protected the islets from H/R‐induced injury by decreasing the apoptotic cell ratio and increasing HIF‐1α, HO‐1, and COX‐2 mRNA expression. Seven days after islet transplantation, insulin expression in the MSC‐islets group significantly differed from that of the islets‐alone group. We proposed that MSCs could promote anti‐apoptotic gene expression by enhancing their resistance to H/R‐induced apoptosis and dysfunction. This study provides an experimental basis for therapeutic strategies based on enhancing islet function. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
134.
In the colour contrast effect, the impression of a colour changes according to the situation; cases occur in which the colour appearance is misunderstood. We propose an image signal processing method for preventing such misperception of colour. Many conventional image improving methods emphasize the contrast of images as same as the brain does. However, by their processes, the colour contrast effect is not canceled; we misunderstand the colour. The objective of this study is to perceive original colour. Therefore, we propose an image correction method using inverse processes of the brain in order to cancel the processes of the brain, the colour contrast effect. We verified whether the proposed method corrected the colour contrast effect by conducting a psychological experiment. The results show that the method succeeds in canceling the colour contrast effect. 相似文献
135.
In this study we found that a blue shrimp (Litopenaeus stylirostris) lysozyme gene (Lslzm) was up-regulated in WSSV-infected shrimp, suggesting that lysozyme is involved in the innate response of shrimp to this virus. Shrimp were intramuscularly injected with Lslzm protein to identify how this recombinant protein protects L. stylirostris from WSSV infection and to determine how this protein influences nonspecific cellular and humoral defense mechanisms. Higher survival rates and a lower viral load (compared with controls) were reported for shrimps that were first injected with the Lslzm protein and then infected with WSSV. In addition, the Lslzm expression level and the immunological parameters (including THC, phagocytic activity, respiratory burst activity, phenoloxidase activity and lysozyme activity) were all significantly higher in the WSSV-infected shrimp treated with the Lslzm protein, compared with the controls. These results indicate that lysozyme is effective at blocking WSSV infection in L. stylirostris and that lysozyme modulates the cellular and humoral defense mechanisms after they are suppressed by the WSSV virus. 相似文献
136.
Safaa G. Kumari Brendan Rodoni Heinrich-Josef Vetten Mai Hlaing Loh Angela Freeman Joop van Leur Shiying Bao Xiaoming Wang 《Journal of Phytopathology》2010,158(1):35-39
A virus disease of faba bean ( Vicia faba L.) in China, characterized by leaf yellowing and rolling and plant stunting, was shown to be caused by a virus of the genus Nanovirus based on serological reactions to nanovirus-specific monoclonal antibodies and the generation of polymerase chain reaction amplicons using nanovirus-specific primers. To identify the faba bean-infecting nanovirus, regions of the DNA components encoding the master replication initiator protein and capsid protein of two nanovirus isolates from China were cloned, sequenced and compared with those of other members of the genus Nanovirus . The two Chinese virus isolates shared nucleotide sequence identities ranging from 95 to 98% with the type isolate of Milk vetch dwarf virus (MDV) from Japan. They were thus identified as isolates of MDV, a virus so far known to cause important diseases of legumes in Japan. This is the first record of MDV-infecting faba bean in China. 相似文献
137.
Pollen-expressed F-box gene family and mechanism of S-RNase-based gametophytic self-incompatibility (GSI) in Rosaceae 总被引:1,自引:0,他引:1
Many species of Rosaceae, Solanaceae, and Plantaginaceae exhibit S-RNase-based self-incompatibility (SI) in which pistil-part
specificity is controlled by S locus-encoded ribonuclease (S-RNase). Although recent findings revealed that S locus-encoded F-box protein, SLF/SFB, determines pollen-part specificity, how these pistil- and pollen-part S locus products interact in vivo and elicit the SI reaction is largely unclear. Furthermore, genetic studies suggested that
pollen S function can differ among species. In Solanaceae and the rosaceous subfamily Maloideae (e.g., apple and pear), the coexistence
of two different pollen S alleles in a pollen breaks down SI of the pollen, a phenomenon known as competitive interaction. However, competitive interaction
seems not to occur in the subfamily Prunoideae (e.g., cherry and almond) of Rosaceae. Furthermore, the effect of the deletion
of pollen S seems to vary among taxa. This review focuses on the potential differences in pollen-part function between subfamilies of
Rosaceae, Maloideae, and Prunoideae, and discusses implications for the mechanistic divergence of the S-RNase-based SI. 相似文献
138.
Maki Kiso Kyoko Shinya Masayuki Shimojima Ryo Takano Kei Takahashi Hiroaki Katsura Satoshi Kakugawa Mai thi Quynh Le Makoto Yamashita Yousuke Furuta Makoto Ozawa Yoshihiro Kawaoka 《PLoS pathogens》2010,6(8)
Influenza viruses resistant to antiviral drugs emerge frequently. Not surprisingly, the widespread treatment in many countries of patients infected with 2009 pandemic influenza A (H1N1) viruses with the neuraminidase (NA) inhibitors oseltamivir and zanamivir has led to the emergence of pandemic strains resistant to these drugs. Sporadic cases of pandemic influenza have been associated with mutant viruses possessing a histidine-to-tyrosine substitution at position 274 (H274Y) in the NA, a mutation known to be responsible for oseltamivir resistance. Here, we characterized in vitro and in vivo properties of two pairs of oseltaimivir-sensitive and -resistant (possessing the NA H274Y substitution) 2009 H1N1 pandemic viruses isolated in different parts of the world. An in vitro NA inhibition assay confirmed that the NA H274Y substitution confers oseltamivir resistance to 2009 H1N1 pandemic viruses. In mouse lungs, we found no significant difference in replication between oseltamivir-sensitive and -resistant viruses. In the lungs of mice treated with oseltamivir or even zanamivir, 2009 H1N1 pandemic viruses with the NA H274Y substitution replicated efficiently. Pathological analysis revealed that the pathogenicities of the oseltamivir-resistant viruses were comparable to those of their oseltamivir-sensitive counterparts in ferrets. Further, the oseltamivir-resistant viruses transmitted between ferrets as efficiently as their oseltamivir-sensitive counterparts. Collectively, these data indicate that oseltamivir-resistant 2009 H1N1 pandemic viruses with the NA H274Y substitution were comparable to their oseltamivir-sensitive counterparts in their pathogenicity and transmissibility in animal models. Our findings highlight the possibility that NA H274Y-possessing oseltamivir-resistant 2009 H1N1 pandemic viruses could supersede oseltamivir-sensitive viruses, as occurred with seasonal H1N1 viruses. 相似文献
139.
Jinchuan Deng Bin Liao Mai Ye Dongmei Deng Chongyu Lan Wensheng Shu 《Plant and Soil》2007,297(1-2):83-92
The genetic diversity and population structure of seven populations of Sedum alfredii growing in lead/zinc (Pb/Zn) mine spoils or in uncontaminated soils from eastern and southern China were investigated using
random amplified polymorphic DNA (RAPD) technology. Four of the sampled sites were heavily contaminated with heavy metals
(Zn, Cd, Pb), and extremely high concentrations of Zn, Cd, and Pb were found among these corresponding populations. A significant
reduction of genetic diversity was detected in the mining populations. The reduction of genetic diversity could be derived
from a bottleneck effect and might also be attributed to the prevalence of vegetative reproduction of the mining populations.
Analysis of molecular variance (AMOVA) and the unweighted pair group method with arithmetic mean (UPGMA) tree derived from
genetic distances further corroborated that the genetic differentiation between mine populations and uncontaminated populations
was significant. Polymorphism with the heavy metal accumulation capability of S. alfredii probably due to the genetic variation among populations and heavy metal contamination could have more impact on the genetic
diversity and population structure of S. alfredii populations than geographic distance. 相似文献
140.
Production of Recombinant β-Hexosaminidase A, a Potential Enzyme for Replacement Therapy for Tay-Sachs and Sandhoff Diseases, in the Methylotrophic Yeast Ogataea minuta
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Hiromi Akeboshi Yasunori Chiba Yoshiko Kasahara Minako Takashiba Yuki Takaoka Mai Ohsawa Youichi Tajima Ikuo Kawashima Daisuke Tsuji Kohji Itoh Hitoshi Sakuraba Yoshifumi Jigami 《Applied microbiology》2007,73(15):4805-4812
Human β-hexosaminidase A (HexA) is a heterodimeric glycoprotein composed of α- and β-subunits that degrades GM2 gangliosides in lysosomes. GM2 gangliosidosis is a lysosomal storage disease in which an inherited deficiency of HexA causes the accumulation of GM2 gangliosides. In order to prepare a large amount of HexA for a treatment based on enzyme replacement therapy (ERT), recombinant HexA was produced in the methylotrophic yeast Ogataea minuta instead of in mammalian cells, which are commonly used to produce recombinant enzymes for ERT. The problem of antigenicity due to differences in N-glycan structures between mammalian and yeast glycoproteins was potentially resolved by using α-1,6-mannosyltransferase-deficient (och1Δ) yeast as the host. Genes encoding the α- and β-subunits of HexA were integrated into the yeast cell, and the heterodimer was expressed together with its isozymes HexS (αα) and HexB (ββ). A total of 57 mg of β-hexosaminidase isozymes, of which 13 mg was HexA (αβ), was produced per liter of medium. HexA was purified with immobilized metal affinity column for the His tag attached to the β-subunit. The purified HexA was treated with α-mannosidase to expose mannose-6-phosphate (M6P) residues on the N-glycans. The specific activities of HexA and M6P-exposed HexA (M6PHexA) for the artificial substrate 4MU-GlcNAc were 1.2 ± 0.1 and 1.7 ± 0.3 mmol/h/mg, respectively. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern suggested a C-terminal truncation in the β-subunit of the recombinant protein. M6PHexA was incorporated dose dependently into GM2 gangliosidosis patient-derived fibroblasts via M6P receptors on the cell surface, and degradation of accumulated GM2 ganglioside was observed. 相似文献