Bacterial Production in the Recently Flooded Sep Reservoir: Diel Changes in Relation to Dissolved Carbohydrates and Combined Amino Acids

The spatial distribution of bacterial abundance and production were measured every 4 h in a recently flooded oligo-mesotrophic reservoir (the Sep Reservoir, Puy-De-Dôme, France), in relation to concentrations of dissolved carbohydrates and combined amino acids. The concentration of dissolved organic matter (DOM) components in the recently flooded Sep Reservoir were higher than those measured in other lakes of similar trophic status. Short-term variations in the bacterial production in this new reservoir appeared cyclical and endogenous to bacterial communities. These results highlight the need for the evaluation of diel changes in bacterial production, if estimation of the daily production rate of bacteria is to be done accurately for a reliable model of carbon flow through bacterioplankton and ultimately through aquatic microbial food webs. Bacterial growth, measured over time and space, did not appear exclusively governed by DOM components from phytoplankton primary production.     

外源氨基酸胁迫下植物体内游离氨基酸的测定

目的：通过检测外源氨基酸胁迫下植物体内的游离氨基酸含量,探讨氨基酸胁迫下植物生长受抑制的机制。方法：小麦胚接种在加入D-丙氨酸、D-丝氨酸和L-缬氨酸等3种外源氨基酸的培养基中,其发芽和生长会受到强烈抑制。取材胁迫植株和对照植株,提取并用HPLC方法检测游离氨基酸含量,分析主要氨基酸特征的改变。结果：作为处理的胁迫氨基酸在体内有数倍到数十倍的增高,其他氨基酸,尤其是同族及相近族氨基酸的量也出现较大改变,有增加也有减少,有些氨基酸甚至检测不出。结论：在外源氨基酸胁迫下,植物可直接吸收这些氨基酸,胁迫氨基酸在体内的积累。至少影响到了部分氨基酸的合成,使细胞内正常游离态氨基酸的数量增加或减少,这些变化引起代谢失调,进而引起生长抑制。     

Hippocampal Free Amino Acids in Alzheimer's Disease

The free amino acid content of the hippocampus, obtained at postmortem, has been analysed in cases of Alzheimer's disease and compared with normal cases. There were no significant differences in the levels of 23 amino acids including the transmitter candidates γ-aminobutyric, glutamic or aspartic acids. This finding is interpreted in relation to present knowledge of transmitter pathways in the region of the hippocampus. A tendency for some amino acids to be increased in the Alzheimer group reached statistical significance for arginine. This observation is consistent with increased proteolytic or peptidase activity in Alzheimer's disease.     

Enzymatic Production of Amino Acids

Abstract

Insects have extremely sensitive systems of olfaction. These systems have been explored as potential sensors for odourants associated with forensics, medicine, security, and agriculture application. Most sensors based on insect olfaction utilize associative learning to “program” the insects to exhibit some form of behavioural response to a target odourant. To move to the next stage of development with whole-insect programmable sensors, an examination of how odourants are captured, processed and used to create behaviour is necessary. This review article examines how the neurophysiological, molecular, genetic and behavioural system of olfaction works and how an understanding of these systems should lead the way to future developments in whole-insect programmable sensors.     

测定荔枝核中的游离氨基酸

采用氨基酸自动分析仪测定荔枝核水提取液、醇提取液样品。在醇提取液中游离氨基酸的含量高于水提取液,在两种提取液中共检出了21种游离氨基酸(其中4种为未知氨基酸,6种必需氨基酸);已知游离氨基酸的质量分数为307μg.kg-1(醇提取液)和269μg.kg-1(水提取液),总游离氨基酸的质量分数为500μg.kg-1,必需氨基酸的量占总游离氨基酸量的44%。结论:荔枝核中的游离氨基酸具有利用价值。     

Changes in Volatile Fatty Acids and Free Amino Acids during Air-Tobacco Stalks

In our searching program for novel sorbicillin related compounds, three novel compounds, spirosorbicillinols A (1), B (2), and C (3), were isolated from the fermentation broth of the USF-4860 strain isolated from a soil sample. The planar structures of compounds 1–3 were determined from spectroscopic evidence and degradation reaction, and that of 1 was the same as that of 2. The relative stereochemistries of compounds 1–3 were determined by ¹H-¹H coupling constants, the elucidation of HMBC and NOESY spectra in detail. 1 and 2 were stereoisomers at C8 position, each other. We propose that compounds 1 and 2 were formed by exo and endo intermolecular Diels-Alder reaction between sorbicillinol as a diene and scytolide (proposed precursor-1) as a dienophile, respectively. Similarly, we propose that compound 3 was formed by an endo intermolecular Diels-Alder reaction between sorbicillinol and proposed precursor-2.     

Free Amino Acids Mediate Association Preferences in Fish

Chemical information is used in a variety of contexts including habitat recognition, foraging and predator avoidance, and a plethora of studies have shown that an individual's distinct chemical profile can mediate interactions with conspecifics. Interestingly, recent work has revealed that diet alone is sufficient to change the chemical profile of individuals, and with it, the way other individuals perceive and interact with them. Free amino acids are known to be utilised across species in a range of contexts, including during predator–prey and host–parasite interactions, and have been widely postulated to underpin diet‐mediated social interactions, especially in fish. However, so far no empirical evidence has been presented to support this suggestion. Using an established behavioural assay in three‐spined sticklebacks (Gasterosteus aculeatus), we aimed to assess association preferences in groups of fish fed experimental diets which differed by a single free amino acid. Our results demonstrate that free amino acids alone are sufficient to mediate interindividual association preferences, raising the possibility that such a mechanism may be widespread among aquatic animals.     

Use of Dissolved Amino Acids by the Foraminifer Notodendrodes antarctikos

SYNOPSIS. Foraminifera are a ubiquitous and sometimes numericallyimportant component of benthic communities. This paper discussesthe role of free amino acids in the nutrition of Notodendrodesantarctikos, a large arborescent foraminifer from an oligotrophicembayment of the Ross Sea, Antarctica. The effects of temperatureand substrate concentrations suggest a carrier mediated transportsystem which facilitates the accumulation of a wide varietyof free amino acids at concentrations found in the interstitialwaters of its sedimentary habitat. Involvement of isotopicallylabeled amino acids in the metabolism of this organism is discussed.     

Fate of Free Amino Acids and Nucleotides in Spoiling Beef

Fresh beef allowed to undergo microbial spoilage at 7 C showed decreases in quantity and types of amino acids as well as decreases in nucleotides when the initial number of bacteria per gram was high. When the initial number of bacteria was low, decreases were either not detectable or of low orders. It seems, therefore, that low-molecular-weight compounds of the above type support the growth of beef-spoilage bacteria rather than primary beef proteins. These low-molecular-weight compounds provide the probable sources of ammonia, hydrogen sulfide, and other such compounds associated with beef allowed to spoil at low temperatures.     

Free Amino Acids and Phosphorylethanolamine in Milk Whey of Cow

Free amino acids in the milk of cow were investigated in comparison with those in the plasma. The concentrations of most free amino acids in the milk except for a few amino acid were lower than those in the plasma. It appears that the percentage of each amino acid in the milk against the corresponding amino acid in the plasma is the reflexion of casein synthesis in the mammary gland. Nutritional alteration influenced on the level of some amino acids in the milk. Free phosphorylserine, glycerylphosphorylethanolamine, and phosphorylethanolamine were observed in the milk. Phosphorylethanolamine was present in significantly high concentration in one animal as control, whereas was almost absent in another animal as experimental.     

Human Adenoviruses and Coliphages in Urban Runoff-Impacted Coastal Waters of Southern California

A nested-PCR method was used to detect the occurrence of human adenovirus in coastal waters of Southern California. Twenty- to forty-liter water samples were collected from 12 beach locations from Malibu to the border of Mexico between February and March 1999. All sampling sites were located at mouths of major rivers and creeks. Two ultrafiltration concentration methods, tangential flow filtration (TFF) and vortex flow filtration (VFF), were compared using six environmental samples. Human adenoviruses were detected in 4 of the 12 samples tested after nucleic acid extraction of VFF concentrates. The most probable number of adenoviral genomes ranged from 880 to 7,500 per liter of water. Coliphages were detected at all sites, with the concentration varying from 5.3 to 3332 PFU/liter of water. F-specific coliphages were found at 5 of the 12 sites, with the concentration ranging from 5.5 to 300 PFU/liter. The presence of human adenovirus was not significantly correlated with the concentration of coliphage (r = 0.32) but was significantly correlated (r = 0.99) with F-specific coliphage. The bacterial indicators (total coliforms, fecal coliforms, and enterococci) were found to exceed California recreational water quality daily limits at 5 of the 12 sites. However, this excess of bacterial indicators did not correlate with the presence of human adenoviruses in coastal waters. The results of this study call for both a reevaluation of our current recreational water quality standards to reflect the viral quality of recreational waters and monitoring of recreational waters for human viruses on a regular basis.     

海南青牛胆中游离氨基酸的分析

对海南青牛胆(Tinospora hainanesis H.S.Lo et Z.X.Li)藤茎中游离氨基酸进行了测定。结果表明,海南青牛胆中游离氨基酸种类极其丰富,其含量总游离氨基酸为0．27％,人体必需氨基酸占总游离氨基酸选75％,精氨酸含量最高,为0．0909％。     

不同产地天麻氨基酸的含量测定

氨基酸用途广泛,人们对氨基酸质量和品种的要求也越来越高.我国氨基酸从无到有,到现在的大市场份额,经历了五十多年的发展历程,其中包括谷氨酸、赖氨酸、苏氨酸和蛋氨酸在内的大品种氨基酸已经发展成为全球的主要供应品种,部分小品种氨基酸已形成自己的优势.绿色制造和现代生物技术的应用将成为氨基酸行业发展的主流.本文重点论述了我国氨基酸品种的现状、水平以及未来发展方向.     

几种氨基酸在庆大霉素生产中作用的研究

庆大霉素是氨基糖苷类广谱抗生素,其不仅用于临床治病,而且广泛应用于畜牧业。由于其发酵周期长,产素率低,生产成本高,因此改进生产方法势在必行。本文报道了在绛红色小单孢菌产生庆大霉素的培养过程中,添加一定量的甘氨酸、蛋氨酸、赖氨酸、酪氨酸能够有效地提高微生物细胞的代谢能力,缩短发酵培养周期,提高产素率。本方法是在小试（摇瓶）成功基础上,用5L玻璃发酵罐运转一个多月,取一个月的平均罐批数据表明：新方法较原工艺发酵周期缩短30% ~45%,罐批产量增加14% 左右,产素率提高30 % ~95%（因菌种生产能力不同而异）,产品质量符合中国药典2000版（CP2000）、英国药典2000版（BP2000）、美国药典26版（USP26）,生产成本大幅度降低,具有很强的市场竞争力。     

Seasonal Variation in Diel Production Pattern of Centropages tenuiremis in Xiamen Waters, China

The seasonal variations in diel production pattern, and egg hatching time of the copepod Centropages tenuiremis in Xiamen waters, China, were investigated between January and June of 2003. The results show that in the winter–spring (January to early May) the adult females tended to lay subitaneous eggs at night, while in the beginning of summer (late May–June) they tended to lay diapause eggs as well as subitaneous eggs during the daytime. The egg hatching time negatively correlated with water temperature. These results, combined with the fact that C. tenuiremis migrates vertically in Xiamen waters, may explain the reproductive strategy of this dominant species in winter–spring.     

大麦籽粒及花药愈伤组织的游离氨基酸含量分析

对同一基因型大麦花药愈伤组织与籽粒中的游离氨基酸含量尤其是赖氨酸含量之间的关系进行分析,结果表明,对同一基因型而言,愈伤组织及籽粒中的同一氨基酸含量高低具有相同趋势。同时着重分析了愈伤组织中游离脯氨酸的含量与绿苗分化的关系,结果表明游离脯氨酸含量高的愈伤组织,其绿苗分化率较高,说明脯氨酸对绿苗分化具有重要作用。966259的花药愈伤组织及籽粒中的游离氨基酸总含量及游离赖氨酸含量均最高。     

Free Amino Acids in Serine-Antagonized Cells of Tetrahymena pyriformis.

Wragg, June B. (Agricultural Research Service, Beltsville, Md.), Howard Reynolds, and Michael J. Pelczar, Jr. Free amino acids in serine-antagonized cells of Tetrahymena pyriformis. J. Bacteriol. 90:748-754. 1965.-Growth inhibition of Tetrahymena pyriformis by l-serine in a chemically defined medium was reversed by l-arginine in a manner which resembled competitive antagonism. Composition of the free amino acid pools from cells grown in either a balanced amino acid mixture or a mixture with serine concentrations which inhibited growth suggested an antagonism by serine with energy-yielding reactions. Growth in media with excess serine resulted in the accumulation of higher concentrations of free cellular amino acids and an apparent increase in the rate of conversion of arginine to ornithine, as compared with growth in the balanced medium. The results suggested that serine or a metabolic product of serine interferes with the formation of pyruvic acid. In the presence of high levels of serine, arginine appeared to be metabolized more rapidly and to be spared when alanine, aspartic acid, or glutamic acid was added to the unbalanced medium.