产适冷木聚糖酶的海洋产青霉的筛选和诱变

从黄海深层海底泥样中分离到1株产低温木聚糖酶的青霉,经EMS诱变得到11株酶活性提高的菌株,对其中1株产低温木聚糖酶活力最高的菌株产酶性质进行了初步研究。所产木聚糖酶在pH4．6,45℃时酶活可达25．8u／ml,比出发菌株提高126％。诱变后菌株所产木聚糖酶在0℃仍有显著酶活性,达8．2u／ml。     

葡聚糖酶高产菌株的诱变筛选及其摇瓶发酵条件的初步研究

从土壤中分离出的一株产葡聚糖酶酶活31 U／ml的野生菌株,经UV、^60Co、LiCl诱变筛选后得到了产葡聚糖酶高产菌株SB126,经发酵条件优化试验后检测其酶活达到85U／ml,较野生菌株提高了近两倍。葡聚糖酶摇瓶较适发酵条件为：装量30ml(250m1)、转速180r／min、pH7．0、温度30℃、接种量8％、发酵周期5d。     

养虾池好氧反硝化细菌新菌株的分离鉴定及特征

利用间歇曝气选择性富集并对所获菌株的好氧反硝化活性进行检测。筛选到一株亚硝酸盐去除活性较高的好氧反硝化细菌。在溶解氧（D0）为3.80-5．21mg／L的培养条件下。该菌株10h内将亚硝态氮由26．18mg／L降至0;在盐度为0—25之间20h内均可达到同样的去除效果。通过形态学特征、生理生化反应及部分长度16SrDNA序列分析对筛选菌株进行鉴定,初步判定它为嗜麦芽寡养单胞菌Stertotrophomonas maltophilia。亚硝酸盐还原酶基因分析结果表明。该菌株只含亚硝酸盐还原酶nitS基因,其序列与Alcaligenes faecalis A15（后来被重新鉴定为Pseudomonas stutzeri）的nirS基因序列相似。     

一株苯酚降解菌的分离与鉴定

目的：筛选能高效降解苯酚的微生物,并进行初步鉴定。方法：从某焦化厂排水沟采集污泥,通过逐步驯化筛选苯酚降解菌株;利用形态观察、生理生化检测、16SrDNA序列分析进行初步鉴定。结果：筛选获得1株苯酚降解菌JDM-2—1,该菌能够以苯酚为惟一碳源,耐酚能力高达2200mg／L,在30℃和pH7．0条件下,42h内能将800mg／L的苯酚彻底降解;初步鉴定其为球形芽孢杆菌（Bacillus sphaericus）。结论：菌株JDM-2-1是一株高效降解苯酚的球形芽孢杆菌。     

产淀粉酶益生乳杆菌的筛选及鉴定

目的以健康仔猪肠道及粪便样品为基础,从中筛选产淀粉酶的乳杆菌菌株,并评价其作为益生菌候选菌株潜力。方法用MRS培养基分别从仔猪新鲜粪便和小肠黏膜上分离到乳酸菌,采用改良的产淀粉酶选择性培养基初筛得到能降解淀粉活性的菌株,并研究菌株的淀粉水解活性、抗逆能力、粘附特性及对抗生素的敏感性。结果从备选的485株乳酸菌中筛选得到具有初步淀粉酶活性的菌株25株（占总筛选数量的5.2%）,复筛选育得到具有较强淀粉酶活性的乳杆菌3株。进一步研究了这3株乳杆菌的抗逆能力、粘附特性以及对抗生素的耐药性,并对最终选育得到的菌株进行生理生化及16S rRNA分子鉴定。经选育鉴定的罗伊乳杆菌G8-5淀粉降解能力最强,并能耐受pH 3.0的酸度、1.0%的胆盐浓度,在小肠上皮细胞上的粘附效率超过15个以上,并对常用的抗生素具有较高的敏感率。结论罗伊乳杆菌G8-5符合安全益生菌的要求,可以作为产淀粉酶的益生乳杆菌优良的候选菌株。     

猪肠道乳杆菌的筛选及其生物学特性研究

目的从健康仔猪肠道中筛选到用于研制微生态制剂的优良乳杆菌株。方法本研究选用乳杆菌选择培养基LBS、MRS从健康仔猪肠道分离到67株乳杆菌,对其染色镜检、生化试验和耐酸、耐胆汁、耐高温、抑菌活性及动物安全性等生物学特性进行初步研究。结果从其中筛选到3株嗜酸乳杆菌,均能耐受pH3．0的酸度、0．8％～1．0％的牛胆盐和60℃的高温,其代谢产物对猪肠道致病性大肠埃希菌和猪沙门菌具有抑制作用,且对小白鼠无致病性。结论3株嗜酸乳杆菌符合益生菌的要求,可作为猪用益生素制剂的候选菌株。     

Xenorhabdus和Photorhabdus代谢产物体外抗肿瘤活性

用8株昆虫病原线虫共生菌(Xenorhabdus属和Photorhabdus属)的发酵液进行了体外抗肿瘤活性的研究,从中筛选出活性较高的菌株一嗜线虫致病杆菌(Xenorhabdus nematophila CB6)。经有机溶剂萃取和硅胶柱层析对嗜线虫致病杆菌发酵液进行进一步分离,得到5个组分。用MTT法测定体外杀肿瘤细胞作用,发现其中2个组分具有抗肿瘤活性。组分3对HepG2、Hela、BGC-823、A-549、K562和HT-29的IC50分别等于3．1μg／ml、8．5μg／ml、2．1μg／ml、3．0μg／ml、4．4μg／ml和1．5μg／ml;组分5对HepG2、Hela、BGC-823、A-549、K562和HT-29的IC50分别等于0．1μg／ml、1．8μg／ml、0．1μg／ml、0．4μg／ml、1．2μg／ml和0．6μg／ml。同时发现抗肿瘤活性组分对正常人肺成纤维细胞MRC-5和正常人肝细胞L-02生长的影响很小。该研究在国内率先报道了嗜线虫致病杆菌发酵液具有较强抗肿瘤活性,为新药物的研制和开发提供了一条崭新的途径。     

链霉菌菌株A与哈茨木霉T-23原生质体融合条件的研究

报道了链霉菌菌株和哈茨木霉菌株属问原生质体融合构建生防工程菌的前期研究成果,研究结果显示：链霉菌菌株A与哈茨木霉T-23分别以1000μg／ml庆大霉素和50～53℃热灭活120min作为遗传标记;融合系统采用聚乙二醇(PEG)作为促融剂,通过对PEG最佳分子量、浓度、处理时间的筛选,确立最佳融合技术系统,即内含0．05mol／L Ca^2 的35％ PEG6000,融合处理15min。所得融合子经过选择再生培养基培养后,在132株融合子中初步筛选出2株稳定的融合子。经孢子大小和DNA含量测定,确立一株为单倍重组体,另一株为杂合二倍体。     

白酒酒曲中高产四甲基吡嗪菌株的筛选和鉴定

为探索白酒酿造过程中四甲基吡嗪的合成机制,从白酒高温曲中筛选获得具有高产四甲基吡嗪的菌株。本研究应用Voges．Proskauer（V．P）反应和光度法对获得菌株的发酵液中的四甲基吡嗪含量进行测定从而获得高产菌株,综合菌落生长形态,16SrDNA序列分析及飞行时间质谱分析,对高产四甲基吡嗪菌株进行鉴定。结果表明,从曲中筛选获得的16株产乙偶姻菌株,其中S12、B1、S1001及B3产TTMP含量较高,分别为67．4mg／kg、50．7mg／kg、48．9mg／kg和43．2mg／kg。S12经进一步鉴定为Bacillussp．。     

碱性蛋白酶产生菌的筛选及发酵条件考查

从土壤中分离到的167株芽胞杆菌中选出一株高产、稳产碱性蛋白酶菌株A4－3（嗜碱性枯草芽胞杆菌）。该菌株最适产酶条件为（g／100ml）：蔗糖6．0;豆饼水解液10.0;Na2CO31．0;起始pH9．5。在该条件下,经37℃振荡培养48h,酶活力达2612u／ml。     

Type 2 diabetes mellitus in a non-obese mouse model induced by Meg1/Grb10 overexpression

We assessed the possibility of C57BL/6-Tg (Meg1/Grb10)isn(Meg1 Tg) mice as a non-obese type 2 diabetes (2DM) animal model. Meg1 Tg mice were born normal, but their weight did not increase as much as normal after weaning and showed about 85% of normal size at 20 weeks of age. Body mass index of Meg1 Tg mice was also smaller than that of control mice. The glucose tolerance test and insulin tolerance test showed that Meg1 Tg mice had reduced ability to normalize the blood glucose level. Blood urea nitrogen (BUN) in Meg1 Tg mice (19.6 +/- 1.2 mg/dl) was significantly lower than in controls (22.0 +/- 0.8 mg/dl), while plasma triglyceride, insulin, adiponectin, and resistin levels were significantly higher (202.0 +/- 23.4 mg/dl vs 146.3 +/- 23.4 mg/dl, 152.4 +/- 16.3 pg/ml vs 88.1 +/- 16.9 pg/ml, 74.4 +/- 10.9 microg/ml vs 48.3 +/- 7.0 microg/ml, and 4.0 +/- 0.2 ng/ml vs 3.6 +/- 0.2 ng/ml, respectively). Body, visceral fat weight and liver weights were significantly lower (19.6 +/- 0.4 g vs 24.3 +/- 0.3 g, 376.7 +/- 29.6 mg to 507.5 +/- 23.0 mg, and 906.0 +/- 41.8 mg to 1,001.0 +/- 15.1 mg, respectively). Thus, hyperinsulinemia observed in Meg1 Tg mice indicates that their insulin signaling pathway is somehow inhibited. With high fat diet, the diabetes onset rate of Meg1 Tg mice increased up to 60%. These results suggest that Meg1 Tg mice resemble human 2DM.     

Insulin resistance,intramyocellular lipid content,and plasma adiponectin in patients with type 1 diabetes

Insulin resistance is a key pathogenic factor of type 2 diabetes (T2DM); in contrast, in type 1 diabetes (T1DM) it is considered a secondary alteration. Increased intramyocellular lipid (IMCL) content accumulation and reduced plasma adiponectin were suggested to be pathogenic events of insulin resistance in T2DM. This study was designed to assess whether IMCL content and plasma adiponectin were also associated with the severity of insulin resistance in T1DM. We studied 18 patients with T1DM, 7 older and overweight/obese patients with T2DM, and 15 nondiabetic, insulin-resistant offspring of T2DM parents (OFF) and 15 healthy individuals (NOR) as appropriate control groups matched for anthropometric features with T1DM patients by means of the euglycemic hyperinsulinemic clamp combined with the infusion of [6,6-2H2]glucose and 1H magnetic resonance spectroscopy of the calf muscles. T1DM and T2DM patients showed reduced insulin-stimulated glucose metabolic clearance rate (MCR: 5.1 +/- 0.6 and 3.2 +/- 0.8 ml x kg(-1) min(-1)) similar to OFF (5.3 +/- 0.4 ml x kg(-1) x min(-1)) compared with NOR (8.5 +/- 0.5 ml x kg(-1) min(-1), P < 0.001). Soleus IMCL content was increased in T1DM (112 +/- 15 AU), T2DM (108 +/- 10 AU) and OFF (82 +/- 13 AU) compared with NOR (52 +/- 7 AU, P < 0.05) and the result was inversely proportional to the MCR (R2 = 0.27, P < 0.001); an association between IMCL content and Hb A1c was found only in T1DM (R2 = 0.57, P < 0.001). Fasting plasma adiponectin was reduced in T2DM (7 +/- 1 microg/ml, P = 0.01) and OFF (11 +/- 1 microg/ml, P = 0.03) but not in T1DM (25 +/- 6 microg/ml), whose plasma level was increased with respect to both OFF (P = 0.03) and NOR (16 +/- 2 microg/ml, P = 0.05). In conclusion, in T1DM, T2DM, and OFF, IMCL content was associated with insulin resistance, demonstrating that IMCL accretion is a marker of insulin resistance common to both primary genetically determined and secondary metabolic (chronic hyperglycemia) alterations. The increased adiponectin levels in insulin-resistant patients with T1DM, in contrast to the reduced levels found in patients with T2DM and in OFF, demonstrated that the relationship of adiponectin to insulin resistance in humans is still unclear.     

Organic Zn and Cu supplementation imprints on seminal plasma mineral,biochemical/ antioxidant activities and its relationship to spermatozoal characteristics in bucks

This experiment was conducted to study the effect of mineral supplementation on seminal plasma minerals level, biochemical constituents and total antioxidant capacity of Osmanabadi bucks. The study comprised of forty healthy bucks, aged five months were randomly assigned to ten groups (n = 4 per group). The control group was fed with a basal diet without any additional mineral supplementation. In addition to basal diet, treatment bucks were supplemented with three graded doses of organic Zinc (Zn) as 20, 40 and 60 mg/kg dry matter (DM); organic Copper (Cu) as 12.5, 25, 37.5 mg/ kg DM and combination of Zn + Cu as Zn20+Cu12.5, Zn40+Cu25, Zn60+Cu37.5 mg /kg DM basis respectively. Minerals were supplemented for 8 months and the separated seminal plasma used for analysis of minerals, biochemical profile, total antioxidant capacity (TAC), lipid peroxidation (LPO), and protein carbonylation (PC). In treatment groups, significantly lower LPO and PC were observed, except Zn60 and Zn60+Cu37.5, where higher malondialdehyde (MDA) (P < 0.05) formed. The TAC was relatively higher (P < 0.05) in Zn20, Zn40, Cu12.5 and Zn60+Cu37.5 than control. The minerals and biochemical parameters were significantly altered and positive relationship was observed among them. From this study, it was concluded that supplemented minerals changed the seminal plasma minerals profile (Zn- 7–13; Cu- 0.5–1.9 mg/L), reduced the stress (LPO and PC of control Vs treatment as 0.3 Vs 0.1 nmol/ml and 25.7 Vs 4.3 nmol protein carbonyl/mg protein), which improved the sperm quality in Zn40, all Cu treatments and Zn60+Cu37.5 groups respectively.     

Influence of acetylsalicylic acid on oxidation of native and glycated low-density lipoprotein

It is generally accepted that oxidation of low-density lipoproteins (LDL) is a causal factor in the development of atherosclerosis. Non-enzymatic glycosylation of LDL, i.e."glycation", plays a central role in late complications of diabetes mellitus and may initiate and/or accelerate the oxidation process. Therefore, the inhibition of this processes is of major therapeutic relevance. The influence of acetylsalicylic acid (ASA) on the oxidation of native and glycated LDL was studied in vitro. LDL (0.25 mg protein/ml ) was oxidatively modified with 5.0 microM CuSO4. Only at "supratherapeutical" ASA concentrations in the range 0.06-2.0 mg /ml we found a significant concentration-dependent inhibition of LDL oxidation both for native and glycated LDL, which was from 0.2 mg/ml upwards significantly more marked for native LDL than for glycated LDL. The maximal inhibitory effect occurred at 2.0 mg/ml with 89.6% inhibition of LDL-oxidation for native LDL and 64.4% for glycated LDL. At 0.2 mg/ml ASA the respective inhibitory values were 38.5% and 31.0%. For glycated LDL the ASA doses of maximal- and approximately 50%-inhibition, as found for native LDL, were chosen to investigate the inhibitory effect on 2,4,8 and 24 hours oxidation of glycated LDL to monitor the time-dependency of inhibition by ASA. This revealed that ASA only delayed, not permanently inhibited LDL oxidation.     

Immune phagocytosis inhibition by commercial immunoglobulins

Sixteen commercially available immunoglobulins (Ig) and 5 anti-Rho (D) hyperimmune globulins were investigated for immune phagocytosis inhibition (IPI) factors as well as for T, B lymphocytotoxic and monocytotoxic antibodies. All Ig contained IPI factors with lowest inhibitory IgG concentrations ranging from 0.08 to 50 mg/ml. Pepsin-digested Ig was noninhibitory. IPI factors in anti-D preparations were uniformly high (inhibitory IgG concentrations 0.6-2.5 mg/ml). Cytotoxic antibodies against T, B lymphocytes and monocytes were found in 2,2 and 7 products, respectively. Since we have recently shown that IPI is caused by antibodies against major histocompatibility complex antigens, most likely HLA, the hypothesis is put forward that IPI factors in Ig are HLA-related, cytotoxic as well as noncytotoxic antibodies which act via Fc receptor blockade of human monocytes.     

The effect of grapefruit juice and seville orange juice on the pharmacokinetics of dextromethorphan: the role of gut CYP3A and P-glycoprotein

The objective of this study was to determine the effects of grapefruit juice and seville orange juice on dextromethorphan (DM) pharmacokinetics. Eleven healthy volunteers were studied over a 3-week period consisting of 5 study days each separated by a three-day washout. All subjects refrained from drinking caffeine containing beverages (coffee, soda, etc.) 8 h before orally taking DM (30 mg) with 200 ml water, 200 ml grapefruit juice, 200 ml water, 200 ml seville orange juice, and 200 ml water on Study Days 1 to 5. Aliquots of urine samples were assayed and analysed for DM, and the DM metabolites dextrorphan, 3-methoxymorphinan and 3-hydroxymorphinan using a validated HPLC method employing a phenyl column and a fluorescence detection. Results suggests that DM could provide some useful information on P-glycoprotein or related membrane efflux protein activity in the human gastro-intestinal tract. Bioavailability (F) of DM increased significantly with grapefruit and seville orange juice, but only returned to half the baseline value after three days of washout. This confirms that grapefruit and seville orange juice are long-lasting and perhaps irreversible inhibitors of gut CYP3A/P-glycoprotein. Grapefruit and seville orange juice appeared to have the same overall effect on DM pharmacokinetics. In addition, this paper presents a novel method of phenotyping for CYP2D6, CYP3A and P-glycoprotein using DM as a probe.     

Immobilization of a cephalosporin acetylesterase by containment within an ultrafiltration device

A cephalosporin acetylesterase produced by Bacillus subtilis catalyzes the deacetylation of 7-aminocephalosporanic acid (7-ACA). Previous reports from our laboratory described the kinetic constants that characterize the reaction: K_m = 2.8 × 10^?3M, K_ia acetate = 5 × 10^?2M, and K_id deacetyl-7-ACA = 3.6 × 10^?2M. These constants were used to predict the time course of the reaction using the following equation for dual competitive product inhibition. where S_t = mg/ml 7-ACA, A_t = mg/ml acetate, D_t = mg/ml deacetyl-7-ACA. The predicted time course closely matched the time course measured experimentally. The equation also was solved without the inhibition terms and the solution indicated that product inhibition caused about a 30% increase in the time required for complete (>97%) hydrolysis of a 24 mg/ml 7-ACA solution. The esterase was immobilized by containment within an ultrafiltration device. With this technique the enzyme was reused 20 times over an 11 day span to deacetylate 7-ACA solutions containing 4 to 24 mg/ml 7-ACA. The specific activity after the 20th use was the same as the activity prior to the first use, indicating little enzyme inactivation occurred.     

Dextromethorphan affects cocaine-mediated behavioral pattern in parallel with a long-lasting Fos-related antigen-immunoreactivity

In order to understand the underlying mechanisms responsible for the behaviors mediated by dextromethorphan (DM), we examined the effects of DM on locomotor activity and locomotor patterns in mice, and Fos-related antigen immunoreactivity (FRA-IR) of mouse brain following repeated administration of cocaine. Combined treatments (30 min prior to each cocaine administration) with DM dose-dependently decreased locomotor activity for high doses of cocaine (20 mg/kg, i.p./day x 7). DM combinations did not significantly affect hyperactivity for 10 mg cocaine/kg, i.p./day x 7. In contrast, combined treatments with DM increased the locomotor activity for 5 mg cocaine/kg, i.p./day x 7. These results were consistent with alterations in marginal activity. Repeated administration with cocaine or DM increased FRA-IR in the nucleus accumbens (NAc) and striatum which lasted for at least 7 days. Our results suggest that DM exhibits biphasic effects on the locomotor stimulation induced by cocaine, and that locomotor activities are in parallel with FRA-IR of the striatal complex. However, the role of FRA-IR regulated by DM or/and cocaine remains to be further determined.     

Inactivation and activation of various membranal enzymes of the cholesterol biosynthetic pathway by digitonin

The activity of rat liver microsomal squalene epoxidase is inhibited effectively by digitonin. Concentrations of 0.8 to 1.2 mg/ml of digitonin cause total inhibition of microsomal (0.75 mg protein/ml) squalene epoxidase either in microsomes that were pretreated with digitonin and subsequently washed and subjected to epoxidase assay or when digitonin was added directly to the assay. The inhibition of squalene epoxidase by digitonin is concentration-dependent and takes place rapidly within 5 min of exposure of the microsomes to digitonin. Octylglucoside, dimethylsulfoxide, CHAPS, as well as cholesterol or total microsomal lipid extract were ineffective in restoring the digitonin-inhibited squalene epoxidase activity. Epoxidase activity in digitonin-treated microsomes was fully restored by Triton X-100. The reactivation by Triton X-100 displays a concentration optimum with maximal reactivation of the epoxidase (0.7 mg protein/ml) occurring at 0.2% Triton X-100. Microsomal 2,3-oxidosqualene-lanosterol cyclase is also inhibited by digitonin. Higher concentrations of digitonin are required to obtain full inhibition of the cyclase activity and only 40% inhibition of cyclase activity is observed at 1 mg/ml of digitonin. Solubilized (subunit size 55 to 66 kDa) and microsomal (subunit size 97 kDa) 3-hydroxy-3-methylglutaryl CoA reductase are totally unaffected by the same concentration of digitonin. Squalene synthetase, another microsomal enzyme in the biosynthetic pathway of cholesterol, is activated by digitonin. A 2.2-fold activation of squalene synthetase is observed at 0.8 mg/ml of digitonin. The results agree with a model in which squalene, and to a lesser degree 2,3-oxidosqualene, are segregated by digitonin into separate intramembranal pools.(ABSTRACT TRUNCATED AT 250 WORDS)     

丁布对小麦赤霉病菌和玉米小斑病菌的抑制作用

采用菌丝生长速率法和孢子萌发试验法检测了抗菌化合物丁布对小麦赤霉病菌和玉米小斑病菌的抑菌作用。结果表明,丁布在PDA培养基中浓度为0.2-1.0 mg/ml时对两种供试病菌的菌丝生长无抑制作用;丁布浓度为0.4-1.0 mg/ml时对两种供试病菌孢子悬浮液中孢子的萌发具有显著抑制作用;1.0 mg/ml丁布药液中培育15h的小麦赤霉病菌和培育5h的玉米小斑病菌的孢子萌发抑制率分别达到100%和83.6%。