Studies on the Metabolism of Fluoroacetate in the Liver of a Rat

In a rat poisoned with sodium fluoroacetate no accumulation of citrate was found in the liver, while in that of a frog fluoroacetate adtninistration was found to cause a marked increase of citrate. In this paper, it was shown that even in a rat when it was treated with insulin before fluoroacetate administration, citrate accuillulation could be found in the liver. In the experiments in vitro using slices of a rat liver it was also shown that fluoroacetate could cause an accumulation of citrate and inhibited the oxidation of malate in the slices of a normal as well as an insulinized liver.     

Construction and application of urinary system model with functional bladder module

In order to study the construction and application of urinary system model with functional bladder module, bladder model was designed, and appropriate materials was selected to make it, and its performance was studied. The results showed that in the analysis of pressure performance of bladder model, more detrusor instability was found in the model than in the urodynamic test, and there was significant statistical difference (P < 0.01). In the analysis of bladder safety capacity, it was found that the bladder safety capacity in the model was much larger than that measured by urodynamics, and there was significant statistical difference (P < 0.01). In the analysis of detrusor workmanship and contraction rate, it was found that the normal model group was significantly smaller than the obstruction group, and there was significant statistical difference (P < 0.01). Comparing the detrusor contraction rate of the two groups, it was found that the normal group and the obstruction group had significant difference at t3, and there was no statistical difference between the other two groups. Therefore, through this study, it is found that the understanding of urinary system can be enhanced by building bladder model, and the basic operating skills of medical staff can be improved more easily by using bladder model, which achieves the expected results of the experiment. Although some shortcomings have been found in the course of the study, it still provides experimental reference for the clinical study of bladder in the future.     

Carbon metabolism and morphogenesis of aspergillus fonsecaeus,II. nutritional status of culture filtrate and dissimilation by mycelial mat

Summary Culture filtrates ofA. fonsecaeus after its growth on glucose nitrate medium were studied for their nutritional status. It was found that culture filtrates support only the vegetative growth. This led to the conclusion that conditions for vegetative growth are different from those of asexual reproduction in this fungus.Efficiency of the fungus in utilization of glucose has been expressed in a ratio and it was found that economic coefficient in the case of this fungus ranges from 30 to 75.As regards the effect of culture filtrate on root elongation of different germinated seeds, it was found that in some cases it is stimulatory and in others it is inhibitory.As regards dissimilation of glucose, it brings about more rapid decomposition of glucose in the replacement culture than in the complete medium and in both cases one of the major metabolic products is oxalic acid.     

Cyclic changes in hormones, carbohydrates and indole metabolism in cervical mucus of normal, fertilizing cows and the relationship with non-fertility

In the cervical mucus of 'normal' cows the cholesterol content was very low at D--0; at D + 12 it was about fifty times as high; then it decreased to about half its value at D + 17 and then to the low value at D--0. Usually small amounts of oestrogen, testosterone, pregnanedione and progesterone were found at D--0; on D + 12 more pregnanedione was found and less oestrogen, while at D + 17 more oestrogen occurred and less pregnanedione. The fructose and glucose content was very low at D--0; then it increased until D + 12, when glucose was dominant, while at D + 17 it had decreased and rather large amounts of glucuronic acid and of sorbitol occurred. On D + 12 a blue fluorescing indole metabolite was sometimes found. Deviations from these patterns, were found particularly in the winter months, and coincided with lowered fertility. Indole metabolism was stronger in the winter months than in the summer months and occurred more in cows than in heifers.     

A study of the cyanogenetic content and toxicity of the fruit of selected species ofCotoneaster

Cyanogenetic glycosides were found to be present in the leaf, bark and fruit of eight species of Cotoneaster. A quantitative determination of cyanogenetic material was made on the leaf, bark and fruit of C. divaricate at three different periods in the growing season. The leaf was found to have the greatest percentage of cyanogenetic glycosides and the fruit the least. Seasonal variation was found to be greatest in the fruit where it was demonstrated that the cyanogenetic content decreased as the fruit aged. Toxicity of the fruit of C. divaricata was studied in the dog, cat and rat. On the basis of the cyanogenetic glycoside determinations and the toxicity studies it was concluded that classification of these eight species of Cotoneaster as poisonous was not warranted.     

The biosynthesis of gangliosides. Labelling of rat brain gangliosides in vivo

1. After injection of [6-(3)H]glucosamine into 8-day-old rats it was found that all the major brain gangliosides and their sialyl groups were labelled at essentially the same rate, except the hematoside, which was the least labelled. In 18-day-old rats it was found that the two major gangliosides with the sialyl (2-->8)-sialyl linkage, and their sialyl groups were more labelled than the hematoside, the Tay-Sachs ganglioside, the other two major gangliosides and their respective sialyl groups. 2. No difference was found in any of the cases studied between the specific radioactivities of the neuraminidase-resistant and -labile sialyl groups belonging to the same ganglioside. The same was found for the specific radioactivities of the galactosyl groups proximal and distal to the ceramide moiety of total brain gangliosides from rats injected with [U-(14)C]glucose. From this it was concluded that partial turnover of the ganglioside molecule does not occur. 3. A model for the synthesis of gangliosides is presented that accounts for results from previous experiments in vitro and the lack of precursor-product relationships observed in experiments in vivo.     

Co-occurrence patterns and morphological similarity of semiaquatic insects (Hemiptera: Gerromorpha) in streams of Eastern Amazonia

1. To understand how the semiaquatic bug communities are shaped, it was first verified whether there was a pattern of co-occurrence between species. It was subsequently tested whether the pattern found was related to environmental variables. Lastly, it was verified whether morphological divergence between species was present in the morphological and functional traits selected. 2. A pattern of species co-occurrence was found in the studied assemblage, related to both environmental variables and interspecific biological interactions. Pairs of species with negative, positive, and random co-occurrence were found. Traits related to predation competition, sexual competition, and interaction with the environment showed significant morphological divergence. 3. Therefore, more than one process defines species co-occurrence patterns in semiaquatic bug communities. It is suggested that environmental influence is related to species microhabitat preference. On the other hand, the morphological divergence found is related to competition and sharing of food resources.     

网织红百分数法测定rHuEPO体内生物学活性的研究

本文通过对网织红百分数法测定rHuEPO体内生物学活性进行研究,找出网织红细胞百分数与rHuEPO浓度线性相关的范围。从而确定了用计数网织红细胞百分数的方法测定rHuEPO体内生物学活性。提出在rHuEPO体内生物学活性测定中选择合适的稀释液至关重要。对(3,3)法测定rHuEPO体内生物学活性进行了统计,批间CV、批内CV均接近10%,单次实验FL%平均数为3126%,并提出鼠间差异是造成FL%较大的主要原因;对(3,3)法与(2,2)法测定rHuEPO体内生物学活性进行比较,发现(2,2)法较(3,3)法更适合用于rHuEPO生产过程中rHuEPO体内生物学活性的测定。     

多年卧孔菌属五个中国新记录种

报道了多年卧孔菌属Perenniporia5个中国新记录种。非洲多年卧孔菌Perenniporia africana采自安徽省,孔口表面浅黄色至赭色,且骨架菌丝不分枝;下延多年卧孔菌P.decurrata采自云南省,担子果盖形,具较小孔口和担孢子;椭圆孢多年卧孔菌P.ellipsospora采自云南省,担子果平伏,孔口圆形至多角形,担孢子不平截;硬多年卧孔菌P.inflexibilis采自福建省,担子果盖形,孔口表面灰白至浅褐色,担孢子无色至浅黄色;黄多年卧孔菌P.xantha采自海南省,孔口较小,表面呈黄色,且在KOH试剂中呈深褐色。根据采集的标本材料提供了它们的详细描述和显微结构图。     

Absence of 5 alpha-reductase in plasma membranes of the hypothalamus in male rats]

No 5alpha-reductase activity was found in plasmic membranes from male rats hypothalami. Contrary to all expectation, it was found that 5alpha-dihydrotestosterone which was synthetized in microsomes or nuclei, was accumulated in plasmic membranes. The significance of this fact is at the moment unknown.     

Enzyme immobilization on colloidal liquid aphrons (CLAs): the influence of system parameters on activity

The novel technique of immobilization of beta-galactosidase on colloidal liquid aphrons (CLAs) was investigated. CLAs are oil-in-water macroemulsions stabilised by a mixture of ionic and nonionic surfactants. Enzyme retention was found to be unaffected by changes in bulk phase pH and ionic strength, indicating that beta-galactosidase immobilization was due primarily to hydrophobic interactions. However, by varying the polarity of the internal solvent core, and the charge of the surfactants used in the formation of the CLAs, it was found that immobilization could be improved to almost 100% under certain conditions indicating that electrostatic interactions also affected immobilization to a lesser degree. Upon immobilization, it was found that there was a shift in the pH optimum of the enzyme, with the immobilized enzyme showing a broader range, and a maximal activity at higher pH. The immobilized beta-galactosidase displayed normal Michaelis-Menten dependence on substrate concentration, whilst also exhibiting superactivity for increased substrate concentrations. Activation energy was determined for the CLA immobilized enzyme, and it was found to decrease indicating that a conformational change had occurred that may account for the observed increase in activity. Finally, although the temperature profile of the immobilized enzyme was similar to the free enzyme, it was very stable, with a potential half-life of 3.6 years at 30 degrees C.     

Studies on the Mechanism of Activation of Pepsinogen

The mechanism of activation of pepsinogen was studied. It was found that no peptide bond cleavage occurred in the molecule of denatured pepsinogen at pH 2. It was inferred from this that a specific secondary and tertiary structure is formed in the molecule of pepsinogen in acid and that it might be necessary for the hydrolysis of the peptide bond. From the circular dichroism studies on pepsinogen and pepsin, it was found that there is a conformational change in the molecule of pepsinogen at pH 4.3~4.5 and that this change is followed by a gradual formation of pepsin.     

Metabolism and disposition of 3,6-dibutanoylmorphine in rat brain

In previous studies from this laboratory it was found that dibutanoylmorphine (DBM) was more potent than morphine as an analgesic in rats and that it was less active than acetyl esters of morphine on behaviour. As DBM is a morphine prodrug, the aim of this work was to determine if rat brain homogenates were capable of deacylating DBM and monobutanoylmorphine (MBM) and to determine relative proportions of parent drug to metabolites in the brain in vivo. In 10% (w/v) brain homogenates, DBM was eliminated with a half-life of about 70 min (corrected for dilution), while MBM was eliminated 10 times as quickly. DBM and its metabolites were found in both blood and brain as early as 1 min after i.v. administration of DBM. After 5 min, the predominant form in blood was MBM and in brain it was DBM. Thus, rat brain possesses the capacity to metabolize DBM by deesterification and the parent drug, MBM, and morphine were found in blood and brain in vivo.     

Clinical Chemical Comparative Examination of Ruminal Samples Collected by Means of a Naso-Ruminal Sampler

Samples of ruminal fluid collected with the COMET naso-ruminal sampler and by two other methods through fistula were subjected to comparative clinical chemical examination. It was found that the mean values of pH and buffer capacity were nearly identical for all three methods. The greatest variation between the methods were found for reduction time of methylene blue owing to different dry matter contents in the samples. The VFA contents were nearly identical in all three samples. In conclusion, it was found that it is possible to obtain ruminal samples that are representative of the biochemical status in the rumen by means of the COMET naso-ruminal sampler in non-fistulated cows.     

Regulation of aromatic amino acid biosynthesis in Escherichia coli K-12: control of the aroF-tyrA operon in the absence of repression control.

Evidence was found which indicated that a mutation in gene trpS affected the rate of synthesis of tyrosine-repressible 3-deoxy-D-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase. The effect was found to occur independently of repression mediated by the tyrR gene product, and it was not due to a change in growth rate, nor was it a manifestation of the stringent response. It is proposed that in the proximal region of the aroF-tyrA operon there is an attenuator site controlled by the level of charged tryptophanyl-transfer RNA. In addition, it was demonstrated that starvation for certain amino acids led to degradation of tyrosine-repressible DAHP synthetase, but not phenylalanine-repressible DAHP synthetase, and supplementation with the missing amino acid led to an increased rate of synthesis of tyrosine-repressible DAHP synthetase during subsequent growth.     

Codonopsis draco Ramp. (桔梗科) 的身份鉴定，特别提及它的濒危状态

Pampanini于1910年发表了桔梗科采自湖北西部的一个新种Codonopsis draco。此后100年无人提起它。最近作者在进行党参属及其近缘类群的专著研究中发现它就是1984年发表的刺萼参Echinocodon lobophyllus DY. Hong, 也采自湖北西部。本文作了新组合。刺萼参在湖北郧西的分布点已经消失,至今仅知道陕西东南部两个地点有少量植株,可见刺萼参已处于濒危状态。因为它是单种属,对其保护应予特别关注。     

意蜂蜂王浆超氧化物歧化酶的分离纯化及部分性质

以意蜂Apis mellifera蜂王浆为材料,经过硫酸铵分段盐析,DEAE-Sepharose 柱层析和Sephacryl S-200凝胶过滤,得到纯化的超氧化物歧化酶(SOD),纯化倍数104.00,比活力53.05 U/mg。该SOD经SDS-PAGE显示单一蛋白带。温度对该酶活力的影响较小。Cu、Zn、Fe和Mn等元素含量测定发现该酶只含有Cu和Zn。酶经圆二色谱测定后,其α螺旋、β折叠和无规则卷曲蛋白构型的含量分别为26.1%、53.8%和22.0%。等电聚焦电泳测得酶的等电点为4.69、4.85和5.01。NR/R单向和双向SDS-PAGE表明该酶含有链内二硫键。氨基酸组成分析发现该酶由约402个氨基酸残基组成,其中Asp、Gly、Leu、Ala、Glu和Val的含量较高。脲可抑制SOD活性,并使其紫外光谱发生变化,荧光发射峰强度变小。溴乙酸（BrAc）抑制酶的活力,使其紫外光谱发生变化,荧光发射峰强度变小。二巯基苏糖醇（DTT）使酶的活力发生变化,紫外吸收峰增大,荧光发射峰变小。     

Structure-Activity Relationship Study of the Bacterial Actin-Like Protein MreB Inhibitors: Effects of Substitution of Benzyl Group in S-Benzylisothiourea

We comprehensively investigated the effects of substitution of the benzyl group in S-benzylisothiourea derivatives on antibacterial activity, because we found previously that some substitutions enhanced it. A 2,4-Cl₂-derivative was found to be the most effective compound, it was stronger than the original one in Gram-negative rod shaped-bacteria such as Escherichia coli and Salmonella typhimurium.     

Celebrating the golden anniversary of the discovery of bacillosamine, the diamino sugar of a Bacillus

Bacillosamine (2,4-diamino-2,4,6-trideoxy-d-glucose, Bac), a rare amino sugar, was discovered 50 years ago as a result of the follow-up of a chance observation made during studies of polypeptide synthesis by a Bacillus subtilis strain later renamed Bacillus licheniformis. In the following decades this amino sugar was almost completely ignored, although it was found in a number of bacterial polysaccharides and other metabolites. Recently, there has been a burst of interest in Bac when it was found to be a link glycan in eubacterial glycoproteins. In this retrospective, I review the chance discovery of Bac, its structural determination and its biosynthesis.     

Sialic acid binding protein of human endometrium: Its regulation by steroids

In the present study, we have observed that sialic acid binding protein (SABP – a 54 kDa glycoprotein which was isolated from human endometrial scrapings taken at various stages of the menstrual cycle from normal cycling females and purified to apparent homogeneity and was earlier reported from this laboratory) was found in sufficiently detectable amount in the endometrium of normal cycling women whereas it was found in lesser amount in tissue from women who have recently entered the post-menopause stage. SABP was observed in both follicular and luteal phase of menstrual cycle which was found by western blot analysis. In the de-novo synthesis experiment, synthesis and secretion of SABP was found to be stimulated by estradiol (E₂) whereas progesterone (P₄) was found to have no significant stimulatory effect on it which was also confirmed by HEC cell culture. In the HEC cell culture, priming of cells with E₂ was found to influence the effect of P₄ on SABP when it was added 2 h after E₂ administration. This was observed by doing immunoprecipitation followed by SDS-PAGE and autoradiography. Hence this report clearly indicates that E₂ regulates the synthesis and secretion of 54 kDa SABP from human endometrium. How E₂ priming of endometrium influences the effect of P₄ on SABP has been discussed.