Novel Active Chrysanthemic Esters

The rates of recycling and turnover of glucose in 5-day- and 21-day-old lambs and adult sheep were measured by the method of single simultaneous injection of glucose-6-³H and glucose-6-¹⁴C. The ³H/¹⁴C ratio decreased linearly with time and was 0.58 and 0.60 in lambs of 5-day- and 21-day-old, respectively, and 0.82 in adult sheep at 120 min after injection of the labeled glucose. The pool size and turnover rate of glucose considerably decreased with age. The rate of glucose recycling was significantly higher in lambs of both ages (22.0 and 26.2%, respectively) than in adult sheep (11.1 %).     

大蒜中生理活性物质对致病细菌的体外抑制作用

目的：从鲜蒜中提取蒜氨酸、蒜氨酸酶和蒜素,测定了蒜氨酸、蒜氨酸酶、蒜氨酸＋蒜氨酸酶、蒜素和蒜汁对10种致病细菌的抑菌作用及最低抑菌浓度。方法：采用平板打孔法和液体2倍稀释法。结果：蒜氨酸酶、蒜氨酸＋蒜氨酸酶、蒜素和蒜汁对金黄色葡萄球菌、大肠杆菌、鲍曼不动杆菌等10种菌株的抑菌环直径均大于7mm。蒜氨酸＋蒜氨酸酶对鲍曼不动杆菌的抑菌作用是50mg／mL氨苄青霉素的1．5倍。蒜氨酸＋蒜氨酸酶对金黄色葡萄球菌、类产碱假单胞菌和福氏志贺氏菌的MIC为0．19mg/mL。结论：蒜氨酸酶、蒜氨酸＋蒜氨酸酶、蒜素和蒜汁在体外具有明显的抑菌作用。     

Structure of a Physiologically Active Polysaccharide Produced by Bacillus polymyxa S-4

The structure of an acidic polysaccharide elaborated by Bacillus polymyxa S-4 was investigated in relation to its physiological activity, particularly, its hypocholesterolemic effect on experimental animals. The polysaccharide is composed of d-glucose, d-mannose, d-galactose, d-glucuronic acid, and d-mannuronic acid (molar ratio 3:3:1: 2:1). Methylation and fragmentation analyses, such as Smith degradation and partial acid hydrolysis showed that the polysaccharide has a complicated, highly branched structure, consisting mainly of (1 → 3)- and (1 → 4)-d-glycosidic linkages. The backbone chain containing d-glucuronic acid, d-mannose, and d-galactose residues is attached at the C-3, C-4, and C-4 positions, respectively, with side chains of single or a few carbohydrate units, which are terminated with d-glucose or d-mannose residues.     

A C-Terminal Phosphatase Module Conserved in Vertebrate CMP-Sialic Acid Synthetases Provides a Tetramerization Interface for the Physiologically Active Enzyme

The biosynthesis of sialic acid-containing glycoconjugates is crucial for the development of vertebrate life. Cytidine monophosphate-sialic acid synthetase (CSS) catalyzes the metabolic activation of sialic acids. In vertebrates, the enzyme is chimeric, with the N-terminal domain harboring the synthetase activity. The function of the highly conserved C-terminal domain (CSS-CT) is unknown. To shed light on its biological function, we solved the X-ray structure of murine CSS-CT to 1.9 Å resolution. CSS-CT is a stable shamrock-like tetramer that superimposes well with phosphatases of the haloacid dehalogenase superfamily. However, a region found exclusively in vertebrate CSS-CT appears to block the active-site entrance. Accordingly, no phosphatase activity was observed in vitro, which points toward a nonenzymatic function of CSS-CT. A computational three-dimensional model of full-length CSS, in combination with in vitro oligomerization studies, provides evidence that CSS-CT serves as a platform for the quaternary organization governing the kinetic properties of the physiologically active enzyme as demonstrated in kinetic studies.     

低温条件下外源生理活性物质对棉铃发育的影响

和4月20日（正常播期）、6月15日（晚播）两个播期条件下．对棉花1～4果枝1、2果节棉铃及其对位果枝叶于花后15d和30d涂抹外源生理活性物质：6％蔗糖和0．6％符氨酰胺混合溶液（C＋N）、2％蔗糖和0．2％谷氨酰胺混合溶液（1／3C＋1／3N）及12%蔗精和1．2％谷氨酰胺混合溶液（2C＋2N）．各浓度处理的C／N比值相同。统计正常播期铃龄50d和纤维加厚发育期（铃龄25～50d）日均温分别为28．5℃、28．1℃．晚播铃龄50d和纤维加厚发育期日均温分刖为22．9℃、21．4℃（超过了相应的临界温度21℃和18℃）。试验结果表明．晚播条件下,花后15dC＋N处理以及花后30d 2C＋2N处理促进了氮和可溶性糖的运转．均使铃重增加最大,分别达0．40g和0．58g。3种浓度外源生理活性物质均增加了纤维素的累积量．且于花后30d促进了螺旋角（φ）和取向分布角（ψ）的优化．提高了纤维比强度．其中以2C＋2N处理提高纤维比强度幅度最大．达1．45cN／tex。花后15d以1／3C＋1／3N处理对提高纤维比强度最有利．达2．10cN／tex。     

Active Metabolites in the Chronic Hepatotoxicity of Pyrrolizidine Alkaloids,including Otonecine Esters

WHEN she reported the chronic hepatotoxicity of the alkaloids senkirkine and hydroxysenkirkine, which are esters of the aminoalcohol otonecine, Schoental¹ suggested that 1,2-epoxides rather than pyrrolic derivatives^2,3 are the active metabolites of hepatotoxic pyrrolizidine alkaloids. We have results which confirm the hepatotoxicity of otonecine esters but argue against the suggested involvement of 1,2-epoxides.     

Low Vitamin D Status and Suicide: A Case-Control Study of Active Duty Military Service Members

Objective

Considering that epidemiological studies show that suicide rates in many countries are highest in the spring when vitamin D status is lowest, and that low vitamin D status can affect brain function, we sought to evaluate if a low level of 25-hydroxyvitamin D [25(OH)D] could be a predisposing factor for suicide.

Method

We conducted a prospective, nested, case-control study using serum samples stored in the Department of Defense Serum Repository. Participants were previously deployed active duty US military personnel (2002–2008) who had a recent archived serum sample available for analysis. Vitamin D status was estimated by measuring 25(OH) D levels in serum samples drawn within 24 months of the suicide. Each verified suicide case (n = 495) was matched to a control (n = 495) by rank, age and sex. We calculated odds ratio of suicide associated with categorical levels (octiles) of 25(OH) D, adjusted by season of serum collection.

Findings

More than 30% of all subjects had 25(OH)D values below 20 ng/mL. Although mean serum 25(OH)D concentrations did not differ between suicide cases and controls, risk estimates indicated that subjects in the lowest octile of season-adjusted 25(OH)D (<15.5 ng/mL) had the highest risk of suicide, with subjects in the subsequent higher octiles showing approximately the same level of decreased risk (combined odds ratio compared to lowest octile  = 0.49; 95% C.I.: 0.315–0.768).

Conclusions

Low vitamin D status is common in active duty service members. The lowest 25(OH)D levels are associated with an increased risk for suicide. Future studies could determine if additional sunlight exposure and vitamin D supplementation might reduce suicide by increasing 25(OH) D levels.     

Antioxidative and Prooxidative Abilities of some Biological Substances and Physiologically Active Substances on the Oxidation of Unsaturated Fatty Acids

Some biological substances and physiologically active substances such as amino acids, hormones, vitamins, medicines and the other substances were added into the linoleic acid solution; and antioxidative and prooxidative abilities of these substances, the abilities to act as electron donors or acceptors, were tested. Many substances were effective as the antioxidant and some others showed prooxidative effects. These facts suggested the possibility of the occurrence of many reactions involving the transfer of an electron among biological processes.     

活性维生素D3对大鼠系膜增生性肾炎PCNA的影响

目的:研究活性维生素D3对大鼠系膜增生性肾小球肾炎的作用及机制.方法:应用抗大鼠胸腺细胞免疫血清(Anti-thymocyte serum,ATS)抗体一次性尾静脉注射复制大鼠系膜增生性肾小球肾炎(Mesangial Proliferative Glomerulonephritis,MsPGN)模型,将实验大鼠分为三组对照组(A组)、模型组(B组)、活性维生素D3治疗组(C组),分别与1、3、7、14天每组各处死6只大鼠,并采用Envision免疫组化法、RT-PCR法,观察PCNA蛋白、PCNAmRNA及中性粒细胞在肾小球中的表达情况.结果:肾炎组增殖细胞核抗原(Proliferating cell nuclear Antigen,PCNA)蛋白、PCNAmRNA及肾小球中中性粒细胞计数明显高于对照组(p＜0.01),并随着时间延长逐渐增高,到第7天达到高峰,第14天有下降的趋势.活性维生素D3治疗组PCNA蛋白、PCNAmRNA及肾小球中中性粒细胞计数的表达均较低(p＜0.01),其中第3、7、14天表达均显著减少(p＜0.05).PCNA蛋白、PCNAmRNA、中性粒细胞计数各指标之间呈均成正相关.结论:活性维生素D3可以抑制系膜细胞的增生,其作用机制可能是抑制炎症细胞浸润、PCNAmRNA及其蛋白的表达.     

微生物转化制备活性维生素D_3的研究进展

活性维生素D类药物作为一类高效原料药,采用化学合成方法,制备复杂,限制了其广泛应用。采用微生物转化法条件温和,操作简单,对于活性维生素D3的制备具有重要意义。从甾体羟化菌株,生物转化制备不同活性维生素D3、基因工程在生物转化上的应用及转化率的影响因素等方面综述了其研究进展,并对该领域的发展趋势进行了展望。     

Processive Endoglucanase Active in Crystalline Cellulose Hydrolysis by the Brown Rot Basidiomycete Gloeophyllum trabeum

Brown rot basidiomycetes have long been thought to lack the processive cellulases that release soluble sugars from crystalline cellulose. On the other hand, these fungi remove all of the cellulose, both crystalline and amorphous, from wood when they degrade it. To resolve this discrepancy, we grew Gloeophyllum trabeum on microcrystalline cellulose (Avicel) and purified the major glycosylhydrolases it produced. The most abundant extracellular enzymes in these cultures were a 42-kDa endoglucanase (Cel5A), a 39-kDa xylanase (Xyn10A), and a 28-kDa endoglucanase (Cel12A). Cel5A had significant Avicelase activity—4.5 nmol glucose equivalents released/min/mg protein. It is a processive endoglucanase, because it hydrolyzed Avicel to cellobiose as the major product while introducing only a small proportion of reducing sugars into the remaining, insoluble substrate. Therefore, since G. trabeum is already known to produce a β-glucosidase, it is now clear that this brown rot fungus produces enzymes capable of yielding assimilable glucose from crystalline cellulose.     

A New Crystalline form of Monosodium l-Glutamate

A new crystalline form of monosodium l-glutamate, which is different from the known monosodium l-glutamate monohydrate crystal in external appearance, density, X-ray diffraction pattern, solubility, and water of crystallization, has been crystallized from ca. 73 weight per cent aqueous methanol solution at ca. 18°C. It was identified as the dihydrate from the determination of water of crystallization based on Karl Fischer′s method. The newly found crystals are extremely unstable in air, aqueous solution, and the mother liquor, because of rapid transformation into the stable monohydrate, whereas they can be kept in a considerably stable condition in absolute ethanol and acetone.