Prevention of Dahl salt-induced hypertension by chronic dietary tryptophan

Four-week-old inbred Dahl salt-sensitive (DS/JR) and Dahl salt-resistant (DR/JR) rats were placed on an 8% salt diet with or without a supplemental 2.5% tryptophan (Trp). Blood pressures were monitored for the next 5 weeks. Urine volumes and ion concentrations were measured during the 6th week. Blood pressures of DS/JR rats on control diets elevated rapidly and markedly, whereas pressures of DS/JR rats on the Trp-supplemented diet were not significantly elevated over those of DR/JR rats. Pressures of DR/JR rats were unaffected by Trp supplementation. Urinary sodium was significantly greater in DR/JR rats compared with DS/JR rats and was unaffected by Trp supplementation. This suggests that the antihypertensive effect of Trp was not at the level of the kidney. We conclude that dietary Trp blocks the development of hypertension in DS/JR rats maintained on a high salt diet.     

Rheological properties of aqueous solution containing xanthan gum and cationic cellulose JR400

Rheological properties of aqueous solution containing xanthan gum (XG) and cationic cellulose JR400 were investigated at different composition ratio, shear rate, pH and electrolyte concentrations. It was found that the mixing of XG and JR400 can induce a viscosity-increasing effect for the mixed solution. As the concentration fraction (f(JR)) of JR400 in the mixed solution increases from 0 to 0.40 with the total polymer concentration (c(t)) of 1%, the solution transforms from an elastic fluid into a viscoelastic one, while as f(JR) decreases from 1 to 0.78, the solution transforms from a viscous fluid into a viscoelastic one. At pH 5-10, both the viscosity and elasticity of XG/JR400 mixture (f(JR)=0.15) are independent of pH and the viscosity-increasing effect is obvious. Outside this pH range, the viscosity, elasticity and viscosity-increasing effect of the mixture decrease. The increase of added NaCl concentration and shear rate can induce the decrease of viscosity, elasticity and viscosity-increasing effect of the XG/JR400 mixture.     

八株芽孢杆菌菌株的分类及固氮活性的测定

从8个省市的不同土壤分离了200个菌株,筛选出8株（JR₁,JR₂,JR₅,ZZ₃,ZZ₁₂,ZZ₁₆,M₁,K₄）能在无氮培养基上生长良好的典型的芽抱杆菌,其中6株（JR₁,JR₂,JR₄和ZZ₃,ZZ₁₂,ZZ     

Drag-reducing properties of bacteria from the skin mucus of the cornetfish (Fistularia commersonii)

Scanning electron microscopy and fluorescence microscopy after scanning with DAPI indicated that the skin mucus of the cornetfish contained large numbers of bacteria, 4 × 10⁸ per cm3. However, viable counts yielded only 2 × 104 per cm³. Twelve bacterial strains were isolated directly from the mucus and another ten strains were obtained following enrichment on pasteurized mucus medium. Most of the isolates belonged to the genus Pseudomonas; a smaller number were classified as Micrococcaceae. Cultures of 13 of the isolates were active in reducing friction in a turbulent flow rheometer. The surface active and drag-reducing properties of three strains—JR5, JR8, and GB7—were studied further. The drag-reducing activities, which were extracellular, were concentrated by ultra-filtration. The chemical composition of the concentrated preparations consisted of 14–24% protein and 38–75% polysaccharide. The major components of the polysaccharide fraction were galacturonic acid, galactosamine, and glucosamine, with lesser amounts of glucose and galactose. The most active preparation, from strain JR8, had a specific drag-reducing activity of 77 units per mg. Strain JR5 was the most hydrophobic as measured by the DOS and BATH tests. JR8 gave intermediate values, and GB8 showed low hydrophobicity values in both tests. The hydrocarbon-in-water emulsifying ability of the concentrated polymer fractions from JR8, GB7, and JR5 were high, intermediate, and low, respectively. The emulsifying and drag-reducing activities of the polymer fraction from strain JR8 were separated from each other by extraction with hydrocarbons. The emulsifying activity was due to a carbohydrate-protein complex, whereas the drag-reducing activity was associated with a uronic acid-containing polysaccharide. Offprint requests to: E. Rosenberg.     

Importance of the relationship between sinus cycle length and junctional rhythm cycle length (occured during radiofrequency ablation) in predicting the successful modification of the slow pathway in Atrioventricular Nodal Re-entrant Tachycardias

Background

In atrioventricular nodal re-entrant tachycardias (AVNRT), the achievement of Junctional Rhythms (JR) during Radiofrequency Ablation (RF) is a sensitive but non-specific marker of success. Our aim is to analyze prospectively the predictors of non-inducibility of AVNRT, focusing on the characteristics of the JR.

Methods

We included 75 patients with reproducibly inducible AVNRT. Ablation was performed following an electro-anatomical approach. After each application, the induction protocol was repeated.

Results

A total of 341 applications were performed. Although the achievement of ≥1 JR was necessary to obtain the non-inducibility, and the cumulative number of junctional beats (CJB) was higher in effective applications, no CJB cut-off was associated with a success rate higher than 75%. After the observation of a significant correlation between the sinus cycle length (CL) pre-RF and the CL of the JR (JR-CL) (c=0.52; p<0.001), the sinus CL pre-RF/JR-CL ratio (CL-ratio) adequately differentiated the successful vs. unsuccessful applications: 1.41±0.23 vs. 1.17±0.2 (p<0.001). In a multivariate analysis, a CBJ 11 (p<0.001) and a CL-ratio 1.25 (p<0.001) were found to be the only independent predictors of success. The combination of ≥ 11 of CJB with a CL ratio ≥ 1.25 achieved non-inducibility in 97% of our patients.

Conclusion

1) The specificity of the occurrence of JR as a marker of the successful ablation of AVNRT is increased by the CL-ratio. 2) The achievement of ≥ 11 of CJB with a CL ratio ≥ 1.25 predicts non-inducibility in almost all patients.     

间作经济作物对黄土丘陵区旱作红枣土壤水分的调控效应

研究行间种植经济作物饲料油菜和黄花菜对黄土丘陵区旱作红枣林地土壤水分的调控效应.结果表明： 饲料油菜和黄花菜处理0～180 cm土层土壤含水量较无作物对照分别提高6.2%和10.1%;枣树生育期内土壤水分变化主要集中在0～60 cm土层,饲料油菜和黄花菜处理均明显增加了0～60 cm土层土壤含水量,保证枣树生育期内正常生长;持续干旱条件下,各处理土壤水分消耗主要在0～60 cm土层,其中0～20 cm土层土壤含水量与次降雨后干旱天数存在显著指数负相关,雨后18 d干旱期饲料油菜和黄花菜处理0～60 cm土层土壤水分含量均高于对照.该间作系统显著改善了红枣林土壤水分环境,是黄土丘陵区克服季节性干旱的有效措施.     

Natural selection for 2,4,5-trichlorophenoxyacetic acid mineralizing bacteria in agent orange contaminated soil

Agent Orange contaminated soils were utilized in direct enrichment culture studies to isolate 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) mineralizing bacteria. Two bacterial cultures able to grow at the expense of 2,4,5-T and/or 2,4-D were isolated. The 2,4,5-T degrading culture was a mixed culture containing two bacteria, Burkholderia species strain JR7B2 and Burkholderia species strain JR7B3. JR7B3 was able to metabolize 2,4,5-T as the sole source of carbon and energy, and demonstrated the ability to affect metabolism of 2,4-D to a lesser degree. Strain JR7B3 was able to mineralize 2,4,5-T in pure culture and utilized 2,4,5-T in the presence of 0.01 yeast extract. Subsequent characterization of the 2,4-D degrading culture showed that one bacterium, Burkholderiaspecies strain JRB1, was able to utilize 2,4-D as a sole carbon and energy source in pure culture. Polymerase chain reaction (PCR) experiments utilizing known genetic sequences from other 2,4-D and 2,4,5-T degrading bacteria demonstrated that these organisms contain gene sequences similar to tfdA, B, C, E, and R (Strain JRB1) and the tftA, C, and E genes (Strain JR7B3). Expression analysis confirmed that tftA, C, and E and tfdA, B, and C were transcribed during 2,4,5-T and 2,4-D dependent growth, respectively. The results indicate a strong selective pressure for 2,4,5-T utilizing strains under field condition.     

Requirement for a second sterol biosynthetic mutation for viability of a sterol C-14 demethylation defect in Saccharomyces cerevisiae.

Genetic analysis of a nystatin-resistant sterol mutant (strain JR4) of Saccharomyces cerevisiae defective in C-14 demethylation revealed the presence of a second mutation in 5,6-desaturation. It appeared from complementation tests that a defect in delta 5-desaturase enzyme activity was required for the viability of the C-14 demethylation mutant. Growth studies with a sterol auxotrophic strain indicated that the major sterol of strain JR4, 14 alpha-methyl-ergosta-8,24(28)-dien-3 beta-ol, could satisfy "bulk" membrane requirements but not the second, structurally specific, sterol function that we defined previously (Rodriguez et al., Biochem. Biophys. Res. Commun. 106:435-441, 1982). Leakiness in the sterol mutations in strain JR4 provided a small amount of ergosterol which could satisfy this second function.     

蛇足石杉内生真菌无柄盘菌Pezicula sp. JR14中抑制乙酰胆碱酯酶的次级代谢产物分离

采用形态学及ITS-rDNA序列分析法,对具有抑制乙酰胆碱酯酶活性的蛇足石杉内生菌株JR14进行鉴定,确定为无柄盘菌Pezicula sp.。开展了乙酰胆碱酯酶抑制活性化合物的分离,从Pezicula sp. JR14乙酸乙酯提取物中分离到4个化合物,利用核磁共振及质谱技术将其鉴定为behenic acid (1)、himeic acid B (2)、secalonic acid A (3)和palmitic acid (4)。采用改进的Ellman比色法对分离的化合物进行活性检测,结果表明,himeic acid B (2)具有较强的乙酰胆碱酯酶抑制活性,其IC₅₀为205μg/mL（0.64mmol/L）。     

Hydrogen peroxide and tumour necrosis factor-alpha induce NF-kappaB-DNA binding in primary human T lymphocytes in addition to T cell lines.

Reactive oxygen intermediates (ROIs), such as hydrogen peroxide (H2O2), have been implicated as second messengers in the activation of NF-kappaB by a variety of stimuli, including tumour necrosis factor-alpha (TNF-alpha). The aim of the present study was to examine the effects of ROIs on NF-kappaB activation in primary human CD3+ T lymphocytes and human peripheral blood mononuclear cells (PBMCs). For comparison purposes, Jurkat T cells (subclones JR and JE6.1) were also investigated. Cells were incubated in the presence of either H2O2 or TNF-alpha and nuclear proteins were extracted. NF-kappaB binding was assessed by electrophoretic mobility shift assays (EMSAs). The concentration of H2O2 required to activate NF-kappaB in human primary CD3+ T lymphocytes was as low as 1 microM. In contrast, much higher concentrations of H2O2 were required to activate NF-kappaB in PBMCs and in the JR subclone of Jurkat T cells. H2O2-induced NF-kappaB activation was not observed in the JE6.1 subclone of Jurkat T cells. NF-kappaB was activated by TNF-alpha in all four cell types tested. In PBMCs and Jurkat T cells (subclones JR and JE6.1), this activation could be inhibited by pre-treatment with the antioxidants, pyrrolidine dithiocarbamate (PDTC) and N-acetyl-L-cysteine (NAC). Our results support a role for ROIs in NF-kappaB-DNA binding in human primary T lymphocytes.     

Effect of a cationic cellulosic polymer on gametophytes of Laminaria digitata (Laminariaceae, Phaeophyta): Improvement of dispersed `free-living' cultures

As filament aggregation is responsible for heterogeneity of Laminariales gametophyte cultures, a project was conducted to obtain stable homogeneous `free-living' cultures of Laminaria digitatagametophytes. The alga was cultivated at 15 ^° Cunder low light and in the presence of a cationic cellulosic polymer, JR125. With 0.1%polymer in the culture medium, the filaments were dispersed and did not adhere to the culture vessel. The absence of any effect of the closely related, but uncharged, polymer LR-250 Natrasol on filament aggregation indicated that the cationic nature of the JR125 molecule was involved in gametophyte dissociation. In the presence of JR125, the gametophytes showed active vegetative growth; the doubling time, measured as chlorophyll concentration, was 5 days. The outer surface of the cell wall was clearly modified by the polymer treatment, as observed by transmission electron microscopy, while neither the inner cell wall or cell organelles were affected. Physiological studies indicated that JR125 treatment did not disturb cell physiology, there being no effecton respiration, photosynthetic activity, sensitivity to high-light stress or modification of pigment or fluorescence characteristics. We have therefore established the conditions for maintaining a stable culture of mixed male and female Laminaria digitata gametophytes in active vegetative growth. The presence of JR 125 in the medium yields a homogeneous culture without cell physiology becoming modified. This revised version was published online in August 2006 with corrections to the Cover Date.     

Marker expression, behaviors, and responses vary in different lines of conditionally immortalized cultured podocytes

The state-of-the-art cultured podocyte is conditionally immortalized by expression of a temperature-sensitive mutant of the SV40 large-T antigen. These cultures proliferate at 33°C and differentiate at 37°C into arborized cells that more closely resemble in vivo podocytes. However, the degree of resemblance remains controversial. In this study, several parameters were measured in podocyte cell lines derived from mouse (JR, KE), human (MS), and rat (HK). In all lines, the quantities of NEPH1 and podocin proteins and NEPH1 and SYNPO mRNAs were comparable to glomeruli, while synaptopodin and nephrin proteins and NPHS1 and NPHS2 mRNAs were <5% of glomerular levels. Expression of Wilms' tumor-1 (WT1) mRNA in mouse lines was comparable to glomeruli, but rat and human lines expressed little WT1. Undifferentiated human and mouse lines had similar proliferation rates that decreased after differentiation, while the rate in rat cells remained constant. The motility of different lines varied as measured by both general motility and wound-healing assays. The toxicity of puromycin aminonucleoside was MS ～ JR > KE, and of doxorubicin was JR ～ KE > MS, while HK cells were almost unaffected. Process formation was largely a result of contractile action after formation of lamellipodia. These findings demonstrate dramatic differences in marker expression, response to toxins, and motility between lines of podocytes from different species and even between similarly-derived mouse lines.     

二株固氮芽孢杆菌的固氮特性研究

在无氮Ｈｉｎｏ培养基ＪＲ_１菌株的乙炔还原活性在氧浓度３％时最高,ＺＺ_１２菌株则随氧浓度上升而下降,但两菌株在空气条件下也能有效固氮;在有０．０１％酵母膏存在时,各氧气浓度菌株的乙炔还原值起伏不大。０．０２％铵盐存在时ＪＲ_１乙炔还原作用最强,但活性随硝酸盐浓度上升而一直下降;０．０２％硝酸盐时ＺＺ_１２菌株乙炔还原力最强,但其活性值随铵盐浓度递增而逐减。土壤中存在可利用糖类时ＪＲ_１和ＺＺ_１２     

4种生态类型稻区节肢动物群落的基本组成与结构特征分析

根据在浙江富阳、河南郑州、江苏句容和湖南长沙的连续田间调查,稻田节肢动物群落的组成依生态学上的营养关系分为植食类（害虫）、捕食类和寄生类（天敌）、以及腐生类和水生类（与水稻关系不甚密切,但可作为天敌的猎物）等。进一步分析显示,不同稻区的节肢动物群落的种－丰盛度关系适于用对数正态分布（Ｌｏｇｎｏｒｍａｌｄｉｓｔｒｉｂｕｔｉｏｎ）模型描述,单一作物生长季节中取样总计少于１０个个体的物种所占比例为４３．７６％－７１．９１％。不同类群的相对丰盛度因地而异,且可是水生类的摇蚊（富阳早稻田）、白背飞虱和褐飞虱（富阳晚稻、句容、长沙）、黑尾叶蝉（郑州）或腐生类的弹尾虫（句容）。多样性（以Ｎ＿１表示）的高低顺序为郑州（２８．５６）＞富阳晚稻（２２．４３）＞句容９１（１１．０８）＞富阳早稻（６．４３）,句容９２（６．８０）,和长沙（６．７２）。极丰盛种所包括的个体数占总个体数量的比例在６９％－８０％之间,具有普遍性的丰盛种有猎物类的褐飞虱、白背飞虱、蚊类、弹尾虫以及捕食类的狼蛛、黑肩绿盲蝽和尖钩宽蝽等,构成了稻田节肢动物群落组成及功能作用的主体。     

拟南芥JR1基因片段的克隆及分析

根据拟南芥CBF基因序列的保守区设计合成一对特异引物,以菠菜基因组DNA为模板,采用PCR扩增的方法扩出一条DNA特异片段并克隆到pUC18载体中。用酶切和测序分析法对克隆片段进行鉴定并进一步进行核苷酸序列分析。序列测定该片段长为430bp。OMIGA2.0软件分析结果表明,该片段与已报道的拟南芥JR1序列的一致性为99.1%。     

Studies on amino acid utilization in relation to virulence of Macrophomina phaseoli causing disease of jute (corchorus capsularis L.)

Amino acid utilization and synthetic capacity of two strains (JR & IR) ofMacrophomina phaseoli, a jute parasite, were compared in relation to their virulence. The effects of an extraneous supply of appropriate amino acid on the pathogenicity of the avirulent strain (IR) were also studied. Chromatographic and growth studies revealed that the avirulent strain contained a greater number of amino acids but its utilizing capacity was much lower than that of the virulent strain (JR). Out of 16 amino acids and an amide tested, phenylalanine was found to be most suitable for the growth of the IR strain, the optimum concentration being 0.5 per cent. This concentration did not, however, affect the resistance of the host after foliar application but temporarily increased the pathogenicity when it was given to the pathogen (IR) in vitro. Phenylalanine was detected neither in mycelia of the tested strains nor in the healthy roots of host plants under test conditions. Efficiency of amino acid utilization could be regarded as one of the important biochemical characteristics of the virulent species.