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661.
Abstract The new planthopper taxon, Garumnella bella gen.n. , sp.n. , from Xizang, China, is described and illustrated, including external morphology of adult and eggs and structures of the male and female genitalia. The new genus is compared with Garumna Melichar and Paragarumna Muir, resulting in Paragarumna ( syn.n. ) being placed as a junior synonym of Garumna, with two new combinations, i.e. Garumna pseudolepida (Muir) comb.n. and Garumna melichari Baker comb.rev. New locality records for Garumna species are given. The morphology of the genitalia and egg of a copulating pair of the new genus is investigated. The female has a ventrally sclerotized posterior vagina forming a torsion groove, an unusual long membranous anterior vagina and an enlarged common oviduct. During copulation both the aedeagus and the torsion groove appear tightly interlocked, which may help to maintain the copulatory position. The aedeagus is observed in the bursa copulatrix.  相似文献   
662.
为明确药用植物委陵菜与其同属植物星毛委陵菜在不同基原之间的代谢差异,更有效的利用药用植物资源。基于气相色谱与质谱联用技术对两药用植物间的小分子初生代谢物进行非靶向代谢组学分析,利用主成分分析和偏最小二乘法分析,寻找可区分两物种的差异代谢物以及在初生代谢途径上的差异。结果:利用GC-MS在两植物中共检测到134个色谱峰,通过与数据库比对,共鉴定出43种初生代谢产物。PCA分析结果显示代谢物在委陵菜和星毛委陵菜间的分布有较大的差异;采用OPLS-DA筛选获得导致2物种区分的差异代谢物共33种,两物种在半乳糖代谢、淀粉和蔗糖代谢、氨酰生物合成、氨基糖和核苷酸糖代谢和果糖和甘露糖代谢途径有显著的差异。委陵菜和星毛委陵菜的初生代谢方面存在较大差异,虽然两植物来源于同科同属植物,但是星毛委陵菜不适合代替委陵菜作为药材使用。  相似文献   
663.
Abstract. Lysozymes are widely distributed in many organisms as one of the components of defence mechanisms. In herbivores, when nitrogen is not contained in sufficient amounts in the diet, bacteria lysed by stomach lysozymes are used as sources of nitrogen. In ruminants, lysozymes function as digestive enzymes in the true stomach. A convergence of amino acid sequence has been shown between the stomach lysozymes of different ruminants, and similar lysozymes have recently been reported in the gut or salivary gland of insects. In this mini review, the enzymatic and ecological functions of lysozymes in insects, particularly in termites, are introduced, together with future studies that are needed in this field.  相似文献   
664.
Start‐up phenomena in microbial biokinetic assays are not captured by the most commonly used growth‐related equations. In this study we propose a new respirometric experimental design to estimate intrinsic growth parameters that allow us to avoid these limitations without data omission, separate mathematical treatment, or wake‐up pulses prior to the analysis. Identifiability and sensitivity analysis were performed to confirm the robustness of the new approach for obtaining unique and accurate estimates of growth kinetic parameters. The new experimental design was applied to establish the metabolic burden caused by the carriage of a pWW0 TOL plasmid in the model organism Pseudomonas putida KT2440. The metabolic burden associated was manifested as a reduction in the yield and the specific growth rate of the host, with both plasmid maintenance and the over‐expression of recombinant proteins from the plasmid contributing equally to the overall effect. Biotechnol. Bioeng. 2010;105: 141–149. © 2009 Wiley Periodicals, Inc.  相似文献   
665.
M Arnó  M B García  J R Pedro  E Seoane 《Steroids》1984,43(3):305-314
The reaction of 2,3-seco-5 alpha-cholestane-2,3-diol and 4 alpha-methyl-2,3-seco-5 alpha-cholestane-2,3-diol with o-nitrophenyl selenocyanate was studied. The diols were synthesized from cholesterol.  相似文献   
666.
In a future scenario of increasing temperatures in North-Atlantic waters, the risk associated with the expansion of the harmful, benthic dinoflagellate Ostreopsis cf. siamensis has to be evaluated and monitored. Microscopy observations and spatio-temporal surveys of environmental DNA (eDNA) were associated with Lagrangian particle dispersal simulations to: (i) establish the current colonization of the species in the Bay of Biscay, (ii) assess the spatial connectivity among sampling zones that explain this distribution, and (iii) identify the sentinel zones to monitor future expansion. Throughout a sampling campaign carried out in August to September 2018, microscope analysis showed that the species develops in the south-east of the bay where optimal temperatures foster blooms. Quantitative PCR analyses revealed its presence across almost the whole bay to the western English Channel. An eDNA time-series collected on plastic samplers showed that the species occurs in the bay from April to September. Due to the water circulation, colonization of the whole bay from the southern blooming zones is explained by inter-site connectivity. Key areas in the middle of the bay permit continuous dispersal connectivity towards the north. These key areas are proposed as sentinel zones to monitor O. cf. siamensis invasions towards the presumably warming water of the North-East Atlantic.  相似文献   
667.
E. Vieitez    E. Seoane    D. V. Gesto    M. C. Mato    A. Vazquez    A. Carnicer  J. Peña 《Physiologia plantarum》1967,20(1):232-244
A study of the cuttings of Salix atrocinerea Brot. was made by extraction with methanol, paper chromatography and Avena coleoptile straight growth test. In the acidic fraction, indole-3-acetic acid (IAA; about 15 μg per kg fresh weight) and p-hydroxybenzoic acid (PHB; about 850 μg per kg fresh weight) were isolated and identified. The growth activity of the different zones is explained by their content of these two compounds. The watersoluble residue, insoluble in ether, showed growth Stimulating activity, which probably is due to a bound auxin (IAA-sugar); alkaline breakdown of this aqueous residue, giving PHB, vanillic and p-coumaric acids, suggests the presence (in the cuttings of Salix atrocinerea) of glycosides with aglycones similar to rhamnacine and scutellareine.  相似文献   
668.
A Tn5 insertion which led to increased susceptibility to multiple drugs, including tetracycline, chloramphenicol, nalidixic acid, erythromycin, spectinomycin, norfloxacin, and novobiocin, was identified in Escherichia coli. Cloning and sequence studies showed that the insertion was in the previously identified prc gene at min 40.4. The prc product is known to function as a protease linked to processing of penicillin-binding protein 3 and lambda repressor and when absent to allow some leakage of periplasmic constituents. Complementation studies with the prc gene on plasmids showed complete recovery of parental levels of susceptibility to all drugs except chloramphenicol, with which only partial reversion to wild-type levels was observed.  相似文献   
669.
熊鹰  艾赣雄  周晨  姚颖  谢庆 《生态学报》2022,42(3):1165-1179
洞庭湖是长江流域重要的调蓄湖泊,也是中国重要的农产品主产区。科学评估洞庭湖区生态可持续状态,揭示其时空演化特征,对探究其生态可持续影响因素与作用机理,降低生态赤字具有重要意义。基于碳足迹与生态足迹理论构建了改进的三维生态足迹模型,填补了化石能源无法核算生态承载力的问题,同时调整了不同土地利用类型的参数因子。在对洞庭湖区25个区县进行可持续发展的动态评价分析中,计算了2000—2019年生态赤字、足迹广度与深度的时空分布特征。研究结果表明:(1)近20年来洞庭湖区的人均生态足迹增长速度远高于人均生态承载力,致使人均生态赤字在时间维度上不断增大,空间维度上呈湖滨向周边地区扩散的趋势;(2)洞庭湖区除林地之外的土地利用类型均存在自然资本存量的消耗,且表现为高生态赤字;(3)三次产业结构的分配、土地利用的变化、居民对生活质量的提高以及生态保护政策的有效实施等均会对洞庭湖区的可持续发展产生较大影响;(4)改进后的化石能源账户相较于传统账户的计算方法更能反映真实的碳排量与碳吸收量。研究以期为洞庭湖区土地利用、生态保护以及促进社会经济可持续发展提供科学参考。  相似文献   
670.
Five wethers were surgically prepared with cranial implants to study the role of gabaminergic neural pathways on the hypothalamic control of feeding behaviour in ruminants. In the first experiment, the animals were injected (1 microL) with a physiological Tyrode (0.95%) solution, muscimol (0.5 and 1.0 nmol), GABA (0.5 and 1.0 nmol), and L-glutamic acid (0.5 and 1.0 nmol). Feed intake following injections of muscimol (1.0 nmol) and L-glutamic acid (0.5 and 1.0 nmol) was twice as large as that following the Tyrode solution, at 60-min postinjections. These results, however, were not statistically significant (p = 0.12-0.15). In the second experiment, the animals were injected (1 microL) with saline, muscimol (0.8 nmol), L-glutamic acid (0.8 nmol), and pentobarbital (0.26 mumol). Fifteen minutes after the injections, pentobarbital had induced a significant feeding response when compared with control values (p less than 0.01), whereas the effect of L-glutamic acid was not significant. However, 30 min after the injections, feed intake of sheep having received L-glutamic acid was higher than that obtained with the control injections (p less than 0.01). The response to pentobarbital was stronger than that to either muscimol or L-glutamic acid. Histological analyses of brain tissue indicated that injections were performed in the ventromedial hypothalamus of four sheep and in the dorsomedial hypothalamus of the other. The data indicate that L-glutamic acid stimulates feed intake by acting either as a precursor of GABA or by a direct stimulation of glutaminergic neural pathways involved in the control of feed intake.  相似文献   
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