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1.
三裂叶野葛毛状根的诱导及其固体培养和液体培养   总被引:6,自引:1,他引:5  
发根农杆菌(Agrobacterium rhizogenes)ATCC15834感染三裂叶野葛(Pueraria phaseoloides)叶片外植体20 d后产生毛状根,毛状根可直接从叶片外植体叶脉处或从叶脉处产生的愈伤组织上产生。感染35d后,约85%的叶片外植体产生毛状根。毛状根能在无外源生长调节剂的 MS固体和液体培养基上自主生长。PCR扩增结果表明,发根农杆菌Ri质粒的rolBrolC基因已在三裂叶野葛毛状根基因组中整合并得到表达。与固体培养的毛状根相比,在液体培养基中培养的毛状根不仅生长迅速,也不会形成愈伤组织。在无外源生长调节剂的液体MS培养基中培养15d的三裂叶野葛毛状根的鲜重、干重、可溶性总糖含量及细胞内活性氧(ROS)含量分别为固体培养毛状根的1.59倍、1.18倍、5.25倍和1.16倍。  相似文献   
2.
Escherichia coli grew aerobically with 2,4,6-trinitrotoluene (TNT) as sole nitrogen source and caused TNT's partial denitration. This reaction was enhanced in nongrowing cell suspensions with 0.516 mol nitrite released per mol TNT. Cell extracts denitrated TNT in the presence of NAD(P)H. Isomers of amino-dimethyl-tetranitrobiphenyl were detected and confirmed with U-15N-labeled TNT.  相似文献   
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4.
The production of lignocellulolytic enzymes by eleven basidiomycetes species isolated from two ecosystems of Georgia was investigated for the first time under submerged (SF) and solid-state fermentation (SSF) of lignocellulosic by-products. Notable intergeneric and intrageneric differences were revealed with regard to the extent of hydrolase and oxidase activity. Several fungi produced laccase along with hydrolases in parallel with growth during the trophophase, showing that the synthesis of this enzyme is not connected with secondary metabolism. The lignocellulosic substrate type had the greatest impact on enzyme secretion. Some of the substrates significantly stimulated lignocellulolytic enzyme synthesis without supplementation of the culture medium with specific inducers. Exceptionally high carboxymethyl cellulase (CMCase, 122 U ml−1) and xylanase (195 U ml−1) activities were revealed in SF of mandarin peelings by Pseudotremella gibbosa IBB 22 and of residue after ethanol production (REP) by Fomes fomentarius IBB 38, respectively. The SSF of REP by T. pubescens IBB 11 ensured the highest level of laccase activity (24,690 U l−1), whereas the SSF of wheat bran and SF of mandarin peels provided the highest manganese peroxidase activity (570–620 U l−1) of Trichaptum biforme IBB 117. Moreover, the variation of lignocellulosic growth substrate provides an opportunity to obtain enzyme preparations containing different ratios of individual enzymes.  相似文献   
5.

Background

Recent experimental evidence suggests that socioeconomic characteristics of neighbourhoods influence cardiovascular health, but observational studies which examine deprivation across a wide range of cardiovascular diseases (CVDs) are lacking.

Methods

Record-linkage cohort study of 1.93 million people to examine the association between small-area socioeconomic deprivation and 12 CVDs. Health records covered primary care, hospital admissions, a myocardial infarction registry and cause-specific mortality in England (CALIBER). Patients were aged ≥30 years and were initially free of CVD. Cox proportional hazard models stratified by general practice were used.

Findings

During a median follow-up of 5.5 years 114,859 people had one of 12 initial CVD presentations. In women the hazards of all CVDs except abdominal aortic aneurysm increased linearly with higher small-area socioeconomic deprivation (adjusted HR for most vs. least deprived ranged from 1.05, 95%CI 0.83–1.32 for abdominal aortic aneurysm to 1.55, 95%CI 1.42–1.70 for heart failure; I2 = 81.9%, τ2 = 0.01). In men heterogeneity was higher (HR ranged from 0.89, 95%CI 0.75–1.06 for cardiac arrest to 1.85, 95%CI 1.67–2.04 for peripheral arterial disease; I2 = 96.0%, τ2 = 0.06) and no association was observed with stable angina, sudden cardiac death, subarachnoid haemorrhage, transient ischaemic attack and abdominal aortic aneurysm. Lifetime risk difference between least and most deprived quintiles was most marked for peripheral arterial disease in women (4.3% least deprived, 5.8% most deprived) and men (4.6% least deprived, 7.8% in most deprived); but it was small or negligible for sudden cardiac death, transient ischaemic attack, abdominal aortic aneurysm and ischaemic and intracerebral haemorrhage, in both women and men.

Conclusions

Associations of small-area socioeconomic deprivation with 12 types of CVDs were heterogeneous, and in men absent for several diseases. Findings suggest that policies to reduce deprivation may impact more strongly on heart failure and peripheral arterial disease, and might be more effective in women.  相似文献   
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7.
The aim of this study was to assess the interactions between Saccharomyces cerevisiae and lactic acid bacteria that either form a stable consortium in Greek wheat sourdoughs (i.e. Lactobacillus sanfranciscensis and L. brevis) or occasionally constitute the secondary microbiota (i.e. Weissella cibaria, L. paralimentarius, Pediococcus pentosaceus and Enterococcus faecium). For this purpose, wheat dough was prepared by using strains of the above mentioned species either as single starters, or in combination of the yeast with each of the lactic acid bacteria strains. The determination of the metabolic products in sourdough samples was performed by HPLC analysis. Presence of lactic acid bacteria had no effect on S. cerevisiae final cell yield but affected negatively the maximum specific growth rate. Ethanol production was primarily affected negatively while the co-culture had a variable effect on glycerol production. On the other hand, the presence of S. cerevisiae favoured mannitol and acetic acid production, had a species-dependent effect on maximum specific growth rate and had no effect on final cfu/g sourdough and lactic acid production by the lactic acid bacteria and at the same time caused the depletion of glucose, fructose and maltose.  相似文献   
8.
9.
Haematophagous insects are frequently carriers of parasitic diseases, including malaria. The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa and is thus responsible for thousands of deaths daily. Although the role of olfaction in A. gambiae host detection has been demonstrated, little is known about the combinations of ligands and odorant binding proteins (OBPs) that can produce specific odor-related responses in vivo. We identified a ligand, indole, for an A. gambiae odorant binding protein, AgamOBP1, modeled the interaction in silico and confirmed the interaction using biochemical assays. RNAi-mediated gene silencing coupled with electrophysiological analyses confirmed that AgamOBP1 binds indole in A. gambiae and that the antennal receptor cells do not respond to indole in the absence of AgamOBP1. This case represents the first documented instance of a specific A. gambiae OBP–ligand pairing combination, demonstrates the significance of OBPs in odor recognition, and can be expanded to the identification of other ligands for OBPs of Anopheles and other medically important insects.  相似文献   
10.
Laccase from the white rot fungus strain Coriolopsis polyzona was immobilized covalently on the diatomaceous earth support Celite® R-633 using different strategies. A first methodology involved the sequential activation of the support surface with γ-aminopropyltriethoxysilane followed by the reaction of the functionalized surface with glutaraldehyde (GLU) or glyoxal (GLY) and the immobilization of laccase on the activated surface. Another strategy tested the simultaneous internal cross-linking of the protein with GLU or GLY and the immobilization of the laccase on the silanized surface. Finally, these two strategies were modified to test the impact of the concomitant addition of bovine serum albumin (BSA) as a stabilizing agent during the immobilization steps. The highest laccase activity and the greatest degree of activity recovery (tested using 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as the substrate) were achieved by the sequential immobilization procedure using GLU as the cross-linking agent. The solid catalysts featuring internal cross-linking of the protein showed significantly higher stability against several denaturants. The Michaelis–Menten kinetic parameters with respect to ABTS revealed a higher affinity for this substrate in the case of the sequential procedure compared to the simultaneous approach. The biocatalyst formed using GLU in the sequential procedure was applied in a packed bed reactor for the continuous treatment of 5 mg l−1 solutions of the endocrine disrupting chemicals (EDCs) nonylphenol (NP), bisphenol A (BPA) and triclosan (TCS) through repeated batch treatments. All of these EDCs could be eliminated at a contact time of less than 200 min by using, respectively, 3.75 units (U) of laccase activity for BPA and TCS and 1.88 U for NP. These performances of elimination were maintained over five consecutive treatment cycles using the same biocatalyst. This system could also remove these EDCs from 100 mg l−1 solutions. The Michaelis–Menten kinetic parameters with respect to these chemicals showed a decreasing affinity of the solid biocatalyst for NP, TCS and BPA in that order.  相似文献   
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