Action of two juvenile hormone antagonists on lepidopteran epidermis

The juvenile hormone antagonist ETB (ethyl-4-2(t-butylcarbonyloxy)-butoxybenzoate) caused formation of precocious larval-pupal intermediates after the 4th (penultimate)-larval instar of the tobacco hornworm, Manduca sexta, when 50 μg were applied to any 3rd stage larvae or to 4th stage larvae within 12 hr after ecdysis. This dose was most effective within 12 hr after ecdysis to the 3rd stage. In the black mutant larval assay for juvenile hormone, ETB had activity, 0.75 μg per larva giving half-maximal score. In vitro ETB acted as a juvenile hormone to prevent the ecdysteroid-induced change in commitment at concentrations above 0.1 μg/ml with an ED₅₀ at 2.8 μg/ml and as a partial juvenile hormone antagonist to 0.1 μg/ml juvenile hormone I at concentrations between 10^?3 and 10^?2 μg/ml. By contrast, EMD (ethyl-E-3-methyl-2-dodecenoate) had little juvenile hormone-like activity in vitro up to its limits of solubility (100 μg/ml) and exhibited sporadic partial juvenile hormone antagonistic activity in vitro at concentrations between 1 and 100 μg/ml. Since these concentrations were 10–1000 times that of juvenile hormone I in the medium, EMD apparently is not an efficient competitor.     

诱导子对藏红花悬浮培养细胞生产藏红花色素的影响

考察壳聚糖（chitosan）、壳寡糖（chitosanoligosaccharides,COS）、茉莉酸甲酯（methyljasmonate,MJ）、水杨酸（salicylicacid,SA）和Cu2＋等诱导子对藏红花悬浮培养细胞生长和藏红花色素合成的影响。结果表明：在实验考察浓度范围内,壳寡糖（1～500mg／L）和较低浓度壳聚糖（≤10mrdL）、MJ（≤10μmol／L）、SA（≤10μμmol／L）和Cu2＋（≤1μmoL／L）对细胞生长无显著影响;较高浓度壳聚糖（≥100mg／L）、MJ（≥100μmol／L）、SA（≥100μmoL／L）和cu“（≥10μmoL／L）显著抑制细胞生长。5种诱导子对藏红花色素合成的诱导效果不同,并且与诱导子作用浓度和添加时间有关。MJ诱导效果最好,在细胞培养第0天添加终浓度100仙moL／LMJ,藏红花色素含量（以1克干细胞计）达到28．57mg,比对照提高177．9％。其次是cu“,在细胞培养第4天添加终浓度500μmoL／LCu2＋,色素含量达到19．82mg,比对照提高108．2％。再次是壳聚糖和壳寡糖,在细胞培养第14天分别添加终质量浓度100mg／L壳聚糖和壳寡糖,色素含量分别达到18．33和17．39mg,比对照提高69．1％和69．0％。最后是SA,在细胞培养第14天添加终浓度10μmoL／LSA,色素含量达到14．65mg,比对照提高45．4％。     

2007年10月南海北部浮游纤毛虫的丰度和生物量

报道2007年10月南海北部海域(21°25.47′N 17°24.95′N,109°28.86′E 113°13.01′E)纤毛虫丰度和生物量的水平分布及砂壳纤毛虫的种丰富度。包括了13个断面的82个站位,Rosette采水器采水,水深低于15 m的站位采0,5 m和10 m;小于30 m站位,采0,10 m和底层;大于30 m的站位,采0,10,30 m和底层。纤毛虫丰度为0 5757 ind./L,平均(848±776)ind./L。无壳纤毛虫占绝对优势,其丰度占纤毛虫总丰度的比例平均为(91.9±9)%;纤毛虫生物量为0 12.09μg C/L,平均是(1.2±1.54)μg C/L,无壳纤毛虫的生物量平均为(0.94±1.27)μg C/L,占纤毛虫总生物量的78.6%。共发现砂壳纤毛虫16个属,49种,拟铃虫最多,具有一定的季节性。纤毛虫水体(40 m到表层)丰度为6.4×1069.1×107ind./m2,平均是(3.6×106±1.4×106)ind./m2;水体生物量3.6 195.8 mg C/m2,平均(48.1±33.7)mg C/m2。纤毛虫多分布于近岸浅水区(高温低盐,高Chl a),最大丰度要高于我国其他海区,不是Chl a最高的地方纤毛虫的丰度也最大,纤毛虫丰度最大时Chl a偏低。     

Behavior of psychrotrophic lactic acid bacteria isolated from spoiling cooked meat products

Three kinds of lactic acid bacteria were isolated from spoiling cooked meat products stored below 10 degrees C. They were identified as Leuconostoc mesenteroides subsp. mesenteroides, Lactococcus lactis subsp. lactis, and Leuconostoc citreum. All three strains grew well in MRS broth at 10 degrees C. In particular, L. mesenteroides subsp. mesenteroides and L. citreum grew even at 4 degrees C, and their doubling times were 23.6 and 51.5 h, respectively. On the other hand, although the bacteria were initially below the detection limit (<10 CFU/g) in model cooked meat products, the bacterial counts increased to 10(8) CFU/g at 10 degrees C after 7 to 12 days.     

Decomposition of gibberellic acid in aqueous solutions

Исследовалось влияние рН и температуры на гидролитическое разложение гибберелевой кислоты в бу?ерных водных растворах. Отдельные продукты гидролиха определяли с помощью хроматогра?ии на бумаге при одновременной спектро?отометриче ской оцерке концентрации образующейся гиббереленовой кислоты. Было установлено, что разложение гибберелевой кислоты в кислой, нейтральной и щелочной среде начинается с образования 1-карбокси-2,3,7-тригидрок си-1-метил-8-метиленгиб б-4-ен 1–3лактон 10 карбоно войкислоты. Это вещес твоприсутствует так же в?ерментационных средах и на различных этапах выделения гибберелевой кислоты. Дальнейшее разложение в растворах с рН 2–8 проходит потом через гиббереленовую кислоту до аллогибберовой кислоты. Следующее превращение аллогибберовой кислоты в гибберовую наблюдалось только в растворе с рН 2 иосле 24-часового прогревания при при 100° С. В растворе с рН 9 процесс разложения приводие к образованию 2,3,7-тригидрокси-1-метил-8-м етиленгибб-4-ен 1,10 дикарбоновой кислоты, которая возникает как главный окончательный продукт гидролиза, наряду с небольшим количеством гиббереленовой кислоты, при данном рН также уже не подвергающейся дальнейшим изменениям. Наибольшей устойчивостью гиььерелевая кислота отличается в растворах с рН 3–4. В нейтральной, а в особенности в слабо щелочной среде ее устойчивость резко понижается. Разложение гибберелевой кислоты в водных растворах значительно ускозяется также при повышении температуры.     

Sedimentation coefficient of T-even bacteriophage DNA

The sedimentation coefficient of T2 phage DNA has been studied by zone centrifugation in sector-shaped preparative centrifuge tubes over a concentration range of 0.02–2.0 μg./ml. DNA. These results have been compared to a similar study in the analytical centrifuge of T4 DNA over the range of 0.50–5.75 μg./ml. DNA. A value for the sedimentation coefficient of 60.7 ± 1.8 S. was obtained by the first method and a value of 61.3 ± 1.5 S. by the second.     

Simultaneous determination of rufloxacin, fenbufen and felbinac in human plasma using high-performance liquid chromatography

A simple, specific and sensitive high-performance liquid chromatographic method has been developed for the simultaneous determination of rufloxacin, fenbufen and felbinac in human plasma. Plasma, spiked with internal standard, was vortex-mixed for 1 min with a mixture of dichloromethane-diethyl ether (80:20, v/v). The evaporated extract was dissolved in 0.02 M NaOH. Drugs were resolved at room temperature on a 5 μm Zorbax SAX column (250×4.6 min I.D.) equipped with a 20×4.6 mm anion-exchange Vydac AXGU ( 10 μm particle size) precolumn. The mobile phase consisted of acetonitrile and phosphate buffer (pH 7.0), delivered at a flow-rate of 1.2 ml/min. Detection was made at 280 nm, 2-[4-(2′-Furoyl)phenyl]propionic acid was used as internal standard. The calibration curve was linear from 0.2 to 10μg/ml for rufloxacin, from 0.5 to 30 μg/ml for fenbufen and from 0.2 to 10 μg/ml for felbinac, respectively. The detection limit was 0.1 μg/ml for rufloxacin. 0.3 μg/ml for fenbufen and 0.1 μg/ml for felbinac, respectively.     

Production of extracellular polysaccharides by a Rhizobium species from the root nodules of Melilotus alba

The Rhizobium sp., isolated from the root nodules of the leguminous fodder herb Melilotus alba, produced large amounts of extracellular polysaccharides (EPS) (963.5 μg/ml) in a yeast extract mannitol medium. Growth and EPS production started simultaneously, but EPS production reached its maximum during the stationary phase of growth of the bacteria, at 20 hours. EPS production was increased with all of the thirteen sugars tested. Different nitrogen sources, such as nitrates, glutamic acid, casamino acid and L-asparagine, increased the EPS production although it was inhibited by glycine, nitrite and ammonium salts. Among the vitamins and metal ions, only pyridoxal phosphate and ZnSO₄ promoted EPS production. Attempts were made to optimize the cultural requirements for growth and maximum EPS production. Maximum EPS production (1457.0 μg/ml) was obtained when the medium was supplemented with glucose (1%), pyridoxal phosphate (2 μ g/ml), ZnSO₄ × 7 H₂O (10 μg/ml) and glutamic acid (0.1%). Under these conditions, the production was increased by 254.3% compared to the control. The EPS contained arabinose, xylose and rhamnose monomers. The presence of arabinose and xylose in the EPS produced by a Rhizobium sp. was uncommon.     

Stimulation of cyclic AMP production in the rat ovary by luteinizing hormone: Independence of prostaglandin mediation

In cubation of intact juvenile rat ovaries with luteinizing hormone (LH; 10 μ g/ml) for 20 min caused a ten-fold rise in cyclic AMP concentration, without increasing the activity of “prostaglandin synthetase” in the tissue. Flufenamic acid [N-(α,α,α- trifluoro-m-tolyl) anthranilic acid], aspirin or indomethacin (100 μ g/ml of each added to the incubation medium) inhibited “prostaglandin synthetase” activity by 90%, 97% and 70%, respectively, but did not prevent the stimulatory effect of LH on cyclic AMP formation. Prostaglandin E₂ (10 μ g/ml) also stimulated cyclic AMP formation in vitro, but this action was abolished by flufenamic acid. These findings argue against the hypothesis proposed in the literature that prostaglandins of the E-type are essential for the LH effect on ovarian adenylate cyclase and thus serve as obligatory mediators of cyclic AMP-dependent actions of LH on the ovary.     

Studies on obtaining meiotic chromosomes for analysis in the bull. II. Direct and culture methods

Testicular tissue was obtained by biopsy or by aspiration following castration or slaughter from 32 healthy bulls, 12 to 16 mos of age, using a 20G 2″, 19G 1 1/2″, 18G 1 1/2″ or 16G 1 1/2″ needle attached to a 20 ml syringe. Meiotic preparations were made by processing the tissue directly and/or after 24 hrs in culture. The tissue culture medium consisted of minimum essential medium (Eagle) supplemented with 10% heat inactivated fetal bovine serum, 4 mM L-glutamine, 20 μg/ml follicular stimulating hormone, 40 i.u./ml human chorionic gonadotrophin, 5 μg/ml testosterone and 25 mM HEPES buffer. The pH was adjusted to 7.0. Culture conditions were: cell concentration approximately 100 cells/ml; incubation temperature 31°C, and atmosphere 5% CO₂, 95% air. Satisfactory preparations were obtained from only 40% of biopsies processed directly, but from 57% of biopsies cultured for 24 hrs. With the procedure that was finally developed using a 16G 1 1/2″ needle enveloped in a sterile plastic bag, 87% of biopsies cultured for 24 hrs gave preparations suitable for meiotic analysis.     

杂色云芝产漆酶的发酵条件研究*

本文对杂色云芝（Coriolus versicolor）产漆酶的发酵条件作了研究。结果表明摇瓶实验产漆酶（Laccase）的最佳培养基成分为：可溶性淀粉 2g/L, NH4Cl 24mmol/L, 微量元素混合液 7ml/L, pH3.0柠檬酸—Na2HPO4缓冲溶液 0.01mol/L, KH2PO4 1.4×10-2 mol/L, MgSO4·7H2O 2.03×10-3mol/L, CaCl2·2H2O 6.8×10-4 mol/L, VB1 2.97×10-6 mol/L, 吐温80 4.0g/L, 愈创木酚0.01mmol/L, CuSO4 ·5H2O 0.005mmol/L,最佳发酵条件为培养基初始pH3.0, 菌体生长6d,培养基装量为250ml三角瓶中25ml培养液,25℃条件下振荡培养(150r/min)9d。     

Elevation of serum albumin concentration in analbuminemic rats by administration of 3'-methyl-4-dimethylaminoazobenzene

Albumin-like protein was detected in the serum of analbuminemic rats which have a mutation affecting albumin mRNA processing and genetically lack serum albumin. This protein was identified as rat serum albumin on the basis of molecular weight, immunological property and digestion patterns with proteases. The serum albumin level in analbuminemic rats was 5 μg/ml 4 weeks after birth and increased slightly during aging. By continuous administration of a hepatocarcinogen, 3′-methyl-4-dimethylaminoazobenzene, the level of serum albumin in the mutant rats increased over that of untreated rats and reached a maximum of 32 μg/ml at the 15th week of the carcinogen administration, whereas that of untreated rats was 16 μg/ml at the same time.     

Cytogenetic effects of a food mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and its metabolite, 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), on human and Chinese hamster cells in vitro

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced structural chromosomal aberrations (CAs) and sister-chromatid exchanges (SCEs) in human lymphocytes and human diploid fibroblasts (TIG-7) at concentrations above 12.5 μg/ml in the presence of rat S9 mix. PhIP also elevated the frequencies of SCEs in human lymphocytes in the presence of rat S9 at concentrations above 2.0 μg/ml with dose-dependency. A proximate form of metabolites of PhIP, 2-hydroxyamino-1-methyl -phenylimidazo[4,5-b]pyridine (N-OH-PhIP), caused CAs in human and Chinese hamster fi fibroblast cells in the absence of S9 mix at concentrations above 0.75 μg/ml and 1.25 μg/ml, respectively, which were 10 times lower than the effective concentration of PhIP. No marked differenceswere observed in the cytogenetic sensitivity to N-OH-PhIP between human and Chinese hamster cells, except between lymphocytes obtained from different donors.     

寄生于洪湖经济鱼类鳃上的单殖吸虫包括二新种的描述

本文报告寄生子洪湖经济鱼类鳃上的单殖吸虫共60种,包括描述指环虫和三代虫各一新种,并有若干寄主新记录及长江流域新记录。       

Vascular smooth muscle relaxation by a lectin from Pisum arvense: evidences of endothelial NOS pathway

The vasorelaxant effect of the lectin of Pisum arvense (PAL) seeds was investigated in rat aorta. PAL (10-100 μg/ml) was applied on aorta rings, with or without endothelium, pre-contracted with phenylephrine (Phe; 0.1 μM). Participation of endothelium derived relaxant factors was evaluated incubating the tissue with indomethacin (10 μM), L-nitro arginine methyl ester (L-NAME, 100 μM) and tetraethylammonium (TEA, 5 mM) before addition of PAL. The role of the lectin domain was investigated by addition of PAL into tissue in presence of glucose (3x 10?? M), or N-acetyl Dglucosamine (GlcNAc; 3 x 10?? M). The importance of extracellular calcium (Ca2?e) or interaction with muscarinic receptors in the relaxant effect was evaluated by addition of PAL into aorta rings containing calcium free solution (OCa) and atropine (1 μ M), respectively. PAL induced concentration-dependent relaxation in endothelized aorta (IC50 =58.38 ± 1.87 μg/ml), which was reversed by L-NAME and glucose. The lectin effect was totally inhibited when the preparation was inserted in OCa, but not in presence of atropine. Summarizing, our data showed a relaxant effect of PAL in isolated rat aorta rings in presence of endothelium, suggestive of interaction between the lectin carbohydrate binding sites with specific receptors located in vascular endothelial cells leading to nitric oxide synthase activation. This effect seems to require Ca2?e but is independent on muscarinic receptors interaction.     

Interaction of methylxanthines and gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa: role of phosphodiesterase inhibition

Previous studies showed that methylxanthines increased the antimicrobial activity of gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa. In this study, the effect of non-selective phosphodiesterase (PDE) inhibitors (methylxanthines: aminophylline and caffeine) and partially selective PDE inhibitors, dipyridamole and sildenafil, was evaluated on the antimicrobial activity of gentamicin using checkerboard method. Aminophylline at concentrations of 0.5 and 1 mg/ml reduced the minimal inhibitory concentration (MIC) of gentamicin (2 μg/ml) 2 and 4 times against S. aureus, and at concentrations of 0.5 and 2 mg/ml reduced the MIC of gentamicin (4 μg/ml) 2 and 4 times, respectively, against P. aeruginosa. Caffeine at concentrations of 1 and 2 mg/ml reduced the MIC of gentamicin (2 μg/ml) 4 and 32 times against S. aureus, and at concentrations of 0.12 and 2 mg/ml reduced the MIC of gentamicin (4 μg/ml) 2 and 4 times, respectively, against P. aeruginosa. However, dipyridamole and sildenafil (32 μg/ml) did not show any effect on MIC of gentamicin against S. aureus and P. aeruginosa. These results suggest that methylxanthines could increase gentamicin effects against S. aureus and P. aeruginosa but this effect is not mediated by inhibition of PDE 5, 6, 8, 10 and 11.     

Resistance of Pseudomonas aeruginosa to gentamicin

The resistance to gentamicin 4 μg./ml. of 250 Pseudomonas aeruginosa isolates was measured by a proportion method. Twenty-eight (11.2%) of the cultures fell into the most resistant group, in whose populations between 10 and 100% of the organisms were resistant. A relatively high percentage of urinary isolates and a comparatively low percentage of isolates from respiratory sources occurred in this group. Three of the 28 were resistant to carbenicillin 150 μg./ml. and 6 of 18 tested were as resistant to gentamicin 8 μg./ml. as they were to 4 μg./ml. The distribution of Ps. aeruginosa isolates between the different grades of resistance did not change significantly during the 10 months in which the survey was performed.