金钟藤的危害与利用

金钟藤是旋花科。打花碗属的一种大型缠绕藤本或亚灌木植物。在森林中。它缠绕幼树使其扭曲变形,影响其正常生长;遮蔽成树接受阳光照射,无法进行光合作用,最终导致其死亡。通过介绍金钟藤的生长特点、分布和危害情况。探讨其防治方法及其可利用的可能性和价值。     

石蒜属植物的药用和观赏利用前景

石蒜属植物是重要的药用植物,又是一类优良观赏植物,既可用于园林配置,也可用作切花生产或盆栽。综述了石蒜属植物的药用和观赏价值并对其应用前景进行了探讨,为全面开发利用我国这一丰富的野生资源提供了一些理论基础。     

ABSORPTION AND UTILIZATION OF IRRADIANCE BY CYANOBACTERIAL MATS IN TWO ICE-COVERED ANTARCTIC LAKES WITH CONTRASTING LIGHT CLIMATES

We investigated the under-ice light climate and the efficiency with which light was absorbed and utilized by benthic algal mats in Lakes Hoare and Vanda, two perennially ice-covered lakes in the McMurdo Dry Valleys area of Southern Victoria Land, Antarctica. The ice cover and water column of Lake Vanda were much more transparent than those of Lake Hoare (18% vs. 2% transmission though ice and attenuation coefficients for downwelling irradiance of 0.05 vs. 0.12 m ^{− 1}, respectively). In both lakes the under-ice spectra were dominated by blue-green wavelengths. The benthic flora under perennial ice covers of both lakes comprised thick mucilaginous mats, dominated by cyanobacteria. The mats were well suited to absorb the dominant blue-green wavelengths of the under-ice light, with phycoerythrin being present at high concentrations. The pigment systems of the benthic mats absorbed 30%–50% of the light that reached them, varying with depth and lake. There was a tendency for the percentage of absorption to increase as ambient irradiance decreased. The efficiency of utilization of absorbed irradiance was examined by constructing absorbed irradiance/oxygen evolution curves to estimate community quantum yield. Mats from 13 m in Lake Hoare showed the highest quantum yields, approaching 1 mol of carbon fixed for every 8 mol quanta absorbed under light-limiting conditions. Lake Vanda mats had lower quantum yields, but these increased with depth. Calculated in situ irradiance occasionally exceeded the measured saturating irradiance for oxygen evolution in both lakes, thus efficiency in situ was below the maximum at times. As in other environments, optimization strategies allowed efficient capture and utilization of the lower and middle ranges of experienced irradiance but led to a compromised capacity to use the highest irradiances encountered at each depth.     

江西忍冬属药用植物资源

报道了江西忍冬属药用植物种类、地理分布、临床疗效、化学成分等有关情况,对该属资源的开发利用提出了合理建议。     

Rice genetic resources: history,conservation, investigative characterization and use in Japan

Rice has been grown in Japan for about 3000 years. Although both japonica and indica varieties have been grown in Japan, now japonica rices are grown. Japanese rice breeding has used an ecological breeding approach. While emphasis in rice breeding in the 1940's and 1950's focussed on yield in recent decades quality has been of major importance. Consumer preference and name recognition of high quality varieties, such as Koshihikari, has resulted in slow acceptance of new varieties.Rice germplasm was systematically collected throughout Japan between 1962 and 1963. Subsequent acquisition and collecting, in Japan and other countries, has resulted in 28,000 accessions being conserved in the National Genebank, based at the National institute of Agrobiological Resources (NIAR).Research on genetic diversity of rice using a range of techniques, for example esterase isozymes, has revealed clinal variation in rice radiating from the center of diversity of rice in and around southwest China. Newly found genes in traditional rice germplasm, such as genes for non-elongating mesocotyl, are now routinely identified on the rice genome. Pioneering studies on eco-genetic differentiation of species in the genus Oryza in Japan has revealed much about the complex genepool for which rice evolved.Pest and disease resistance sources, particularly to blast, bacterial blight and brown plant hopper, from many countries have been incorporated into Japanese varieties. Cold tolerance at the booting stage was found in the Indonesian variety Silewah. In the future in characterisation of rice germplasm and interaction between rice germplasm specialists and rice molecular scientists, both in Japan and internationally, will be corner stones to securing rice genetic diversity and rice improvement in the next century.     

Carbon source utilization of soil extracted microorganisms as a tool to detect the effects of soil supplemented with genetically engineered and non-engineered Corynebacterium glutamicum and a recombinant peptide at the community level

Abstract: Substrate utilization of microbial cells extracted from soil with a 0.85% aqueous sodium chloride solution, was determined to estimate effects on soil microorganisms at the community level with microtiter plates (Biolog GN®) containing 95 different sources of organic carbon. A consistent pattern of utilized substrates was obtained after 24 h of microtiter plate incubation at 28°C. The absorbance values (OD₅₉₀) obtained from a microtiter plate reader after background correction were transformed by using the average absorbance values of oxidized substrates as a threshold to distinguish between well utilized and poorly or non-utilized substrates and thereby reduce variances between replicates. Doubling times of the extracted soil microorganisms in the microtiter plates were tested with 12 substrates and ranged from 1.96 h to 3.23 h, depending on the carbon source. The carbon source utilization assay was used to assess the effects of soil inoculation with Corynebacterium glutamicum with and without a genetically engineered plasmid (pUN1; 6.3 kb), which encoded for the synthesis of the mammalian protease inhibiting peptide, aprotinin. Additionally, aprotinin itself was added at two concentrations to soil samples. An identical decrease in the number of carbon sources utilized, especially carbohydrates, occurred upon soil inoculation with both C. glutamicum strains after inoculation with 10⁶ cells g⁻¹ soil. This effect was only detectable during the first three weeks of incubation, as long as cell numbers of C. glutamicum (pUN1) were above 10⁵ cfu g⁻¹. Soil amendment with aprotinin resulted in utilization of additional substrates, most of them carbohydrates. With 0.1 mg aprotinin g⁻¹ soil this stimulation lasted 2 days and with 10 mg g⁻¹ it lasted for 7 days.     

Adaptive laboratory evolution and reverse engineering enhances autotrophic growth in Pichia pastoris

Synthetic biology offers several routes for CO₂ conversion into biomass or bio-chemicals, helping to avoid unsustainable use of organic feedstocks, which negatively contribute to climate change. The use of well-known industrial organisms, such as the methylotrophic yeast Pichia pastoris (Komagataella phaffii), for the establishment of novel C1-based bioproduction platforms could wean biotechnology from feedstocks with alternative use in food production. Recently, the central carbon metabolism of P. pastoris was re-wired following a rational engineering approach, allowing the resulting strains to grow autotrophically with a μ_max of 0.008 h⁻¹, which was further improved to 0.018 h⁻¹ by adaptive laboratory evolution. Using reverse genetic engineering of single-nucleotide (SNPs) polymorphisms occurring in the genes encoding for phosphoribulokinase and nicotinic acid mononucleotide adenylyltransferase after evolution, we verified their influence on the improved autotrophic phenotypes. The reverse engineered SNPs lead to lower enzyme activities in putative branching point reactions and in reactions involved in energy balancing. Beyond this, we show how further evolution facilitates peroxisomal import and increases growth under autotrophic conditions. The engineered P. pastoris strains are a basis for the development of a platform technology, which uses CO₂ for production of value-added products, such as cellular biomass, technical enzymes and chemicals and which further avoids consumption of organic feedstocks with alternative use in food production. Further, the identification and verification of three pivotal steps may facilitate the integration of heterologous CBB cycles or similar pathways into heterotrophic organisms.     

Substantial Metabolic Activity of Human Brown Adipose Tissue during Warm Conditions and Cold-Induced Lipolysis of Local Triglycerides

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Reprogramming of sugar transport pathways in Escherichia coli using a permeabilized SecY protein-translocation channel

In the initial step of sugar metabolism, sugar-specific transporters play a decisive role in the passage of sugars through plasma membranes into cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. The present work shows that permeabilized SecY channels can be used as nonspecific sugar transporters in Escherichia coli. SecY with the plug domain deleted allowed the passage of glucose, fructose, mannose, xylose, and arabinose, and, with additional pore-ring mutations, facilitated lactose transport, indicating that sugar passage via permeabilized SecY was independent of sugar stereospecificity. The engineered E. coli showed rapid growth on a wide spectrum of monosaccharides and benefited from the elimination of transport saturation, improvement in sugar tolerance, reduction in competitive inhibition, and prevention of carbon catabolite repression, which are usually encountered with native sugar uptake systems. The SecY channel is widespread in prokaryotes, so other bacteria may also be engineered to utilize this system for sugar uptake. The SecY channel thus provides a unique sugar passageway for future development of robust cell factories for biotechnological applications.     

不同宿主来源的重组酿酒酵母混合糖代谢比较

【目的】研究不同工业酿酒酵母宿主背景对重组酵母木糖利用效率的影响。【方法】将木糖利用途径的木糖还原酶(XR)、木糖醇脱氢酶(XDH)和木酮糖激酶(XK)编码基因串联后分别转入3株不同的工业酿酒酵母中,得到重组酵母ZQ1、ZQ5和ZQ7。分别对3个木糖途径代谢基因的表达水平、酶活和重组菌株的木糖发酵效率进行比较。【结果】重组菌株在木糖代谢基因转录、酶活性和木糖利用性能方面有很大差异,其中ZQ5木糖代谢能力最强,ZQ7其次,ZQ1木糖利用能力最弱。ZQ7在初始木糖浓度为20 g/L时木糖利用速率快于ZQ5,表明木糖浓度对重组菌发酵性能评价具有影响。【结论】不同菌株的遗传背景和木糖浓度对重组菌木糖利用的影响很大,评价重组酵母的木糖利用需考虑宿主的遗传背景和底物浓度的影响。