Uropathogenic Escherichia coli (UPEC) strains may carry virulence properties of diarrhoeagenic E. coli

To analyze whether Escherichia coli strains that cause urinary tract infections (UPEC) share virulence characteristics with the diarrheagenic E. coli (DEC) pathotypes and to recognize their genetic diversity, 225 UPEC strains were examined for the presence of various properties of DEC and UPEC (type of interaction with HeLa cells, serogroups and presence of 30 virulence genes). No correlation between adherence patterns and serogroups was observed. Forty-five serogroups were found, but 64% of the strains belonged to one of the 12 serogroups (O1, O2, O4, O6, O7, O14, O15, O18, O21, O25, O75, and O175) and carried UPEC virulence genes (pap, hly, aer, sfa, cnf). The DEC genes found were: aap, aatA, aggC, agg3C, aggR, astA, eae, ehly, iha, irp2, lpfA(O113), pet, pic, pilS, and shf. Sixteen strains presented aggregative adherence and/or the aatA sequence, which are characteristics of enteroaggregative E. coli (EAEC), one of the DEC pathotypes. In summary, certain UPEC strains may carry DEC virulence properties, mostly associated to the EAEC pathotype. This finding raises the possibility that at least some faecal EAEC strains might represent potential uropathogens. Alternatively, certain UPEC strains may have acquired EAEC properties, becoming a potential cause of diarrhoea.     

An expeditious synthesis of 4-hydroxy-2E-nonenal (4-HNE), its dimethyl acetal and of related compounds

The facile one step synthesis of 4-hydroxy-2(E)-nonenal and its dimethyl acetal via a cross-metathesis reaction between commercially available octen-3-ol and acrolein or its dimethyl acetal is reported. The method was extended to the synthesis of C₆ and C₁₂ 4-hydroxy-2(E)-enals, their dimethyl acetal and of the 4-hydroxy-2(E)-nonenoic acid (4-HNA).     

Developing pheromone traps and lures for Maruca vitrata in Benin, West Africa

In previous work successful trapping of the legume podborer, Maruca vitrata Fabricius (Lepidoptera: Pyralidae), was accomplished using a synthetic pheromone blend consisting of (E,E)‐10,12‐hexadecadienal, (E,E)‐10,12‐hexadecadienol, and (E)‐10‐hexadecenal in a 100 : 5 : 5 ratio. In the present work, experiments were conducted in cowpea fields in Benin to compare different trap designs, and other aspects of the lures. A water‐trap made from a plastic jerry‐can was found to be superior to commercial funnel‐ and sticky‐trap designs, and 120 cm was the optimum height for captures. Generally, lures consisted of polyethylene vials containing 0.1 mg of pheromone. Results showed that shielding the lures from the adverse effects of sunlight with aluminium foil did not increase trap catches of M. vitrata. The degree of isomeric purity of the (E,E)‐10,12‐hexadecadienal and (E,E)‐10,12‐hexadecadienol blend components, in the range 73–99%, had no significant effect on captures, while lures of 80% isomeric purity showed no loss of effectiveness for up to 4 weeks. Similar results were observed with lures from a commercial source containing 0.46 mg of pheromone in the blend ratio 100 : 11 : 6 and 95% isomeric purity. Residue analysis showed that vial lures exposed for 2 weeks in the field still contained 73% of the initial amount of (E,E)‐10,12‐hexadecadienal, compared to rubber septa dispensers, which only retained 22%. Females comprised 11–50% of total catches, confirming earlier, unexpected results for synthetic lures. The observations that effective traps can be made from locally available plastic containers, and that pheromone blend composition and purity are not critical, should reduce costs and improve the feasibility of traps as practical monitoring tools for M. vitrata.     

Identification of specific binding sites for leukotriene C4 in human fetal lung

Specific leukotriene C₄ (LTC₄) binding sites were identified in membrane preparations from human fetal lung. Specific binding of [³H]-LTC₄ represented 95 percent of total binding, reached steadystate within 10 minutes and was rapidly reversible upon addition of excess unlabeled LTC₄. Binding assays were performed at 4°C under conditions which prevented metabolism of [³H]-LTC₄ (80 mM serineborate, 10 mM cysteine, 10 mM glycine). Under these conditions, greater than 95 percent of the membrane bound radioactivity, as analyzed by high performance liquid chromatography, co-eluted with the LTC₄ standard. Computer-assisted analyses of saturation binding data showed a single class of binding sites with a dissociation constant (K_d) of 26 + 6 nM and a density (B_max) of 84 ± 18 pmol/mg protein. Pharmacological specificity was demonstrated by competition studies in which specific binding of [³H]-LTC₄ was displaced by LTC₄ and its structural analogs with inhibition constants (K_j) of 10 to 30 nM, whereas LTD₄, diastereoisomers of LTD₁, LTE₄ and the end organ antagonist FPL 55712 were 150 to 700 fold less potent competitors than LTC₄. These results provide evidence for specific, reversible, saturable, high affinity binding sites for [³H]-LTC₄ in human fetal lung membranes.     

维生素E对三氯乙烯急性染毒大鼠肝脏脂质过氧化与抗氧化酶的影响

本文观察了用抗氧化剂维生素E预处理后,三氯乙烯(3000mg/kg B-W-) 一次性经口染毒24h 大鼠肝脏的超氧化物歧化酶、谷胱甘肽过氧化物酶等抗氧化酶活力及丙二醛含量的变化,结果表明三氯乙烯染毒组肝脏中丙二醛含量、超氧化物歧化酶活力及血清谷丙转氨酶、谷草转氨酶活力均高于对照组(P< 0-01) ;而维生素E干预组的丙二醛含量、超氧化物歧化酶活力及血清谷丙转氨酶、谷草转氨酶活力均分别低于三氯乙烯染毒组(P< 0-01) ,说明三氯乙烯急性染毒可引起肝脏脂质过氧化反应及肝损害,肝脏超氧化物歧化酶活力升高可能是机体受自由基及脂质过氧化反应刺激而诱导产生的一种适应性反应,维生素E对三氯乙烯所致的肝损害有一定的保护作用。     

Putrescine distribution in Escherichia coli studied in vivo by 13C nuclear magnetic resonance

In order to study the intracellular polyamine distribution in Escherichia coli, ¹³C-NMR spectra of [1,4-¹³C]putrescine were obtained after addition of the latter to intact bacteria. The ¹³C-enriched methylene signal underwent line broadening. When the cells were centrifuged after 90 min the cell-bound putrescine peak had a linewidth of 23 Hz, while the supernatant liquid showed an unbound putrescine signal with a linewidth smaller than 1 Hz. By using ¹³C-enriched internal standards it could be shown that the linewidening was not due to the heterogeneity of the medium or to an in vivo paramagnetic effect. Cell-bound putrescine was liberated by addition of trichloroacetic acid and was therefore non-covalently linked to macromolecular cell structures. Cell-bound [¹³C]putrescine could be displaced by addition of an excess of [¹²C]putrescine. When samples of membranes, soluble protein, DNA, tRNA and ribosomes from E. coli were incubated with [1,4-¹³C]putrescine, strong binding was detected only in the ribosomal and membrane fractions. The ribosome-putrescine complex showed properties similar to those determined with the intact cells. By measuring the nuclear Overhauser enhancements η, it was possible to estimate that only about 50% of the polyamine was linked to the macromolecules. Determination of the T₁ values of free and ribosomal-bound putrescine allowed the calculation of a correlation time, τ_c = 4·10^?7 s for the latter. T₁ and τ_c value for the ribosome-putrescine complex were those expected for a motional regime of slowly tumbling molecules.     

Degradation of 1,3-dichloropropene by a soil bacterial consortium and Rhodococcus sp. AS2C isolated from the consortium

A bacterial consortium capable of degrading the fumigant 1,3-D ((Z)- and (E)-1,3-dichloropropene) was enriched from an enhanced soil. This mixedculture degraded (Z)- and (E)-1,3-D only in the presence of a suitable biodegradable organic substrate, such as tryptone, tryptophan, or alanine. After 8 months of subculturing at 2- to 3-week intervals, a strain of Rhodococcus sp. (AS2C) that was capable of degrading 1,3-D cometabolically in the presenceof a suitable second substrate was isolated. (Z)-3-chloroallyl alcohol (3-CAA) and (Z)-3-chloroacrylic acid (3-CAAC), and (E)-3-CAA and (E)-3-CAAC were the metabolites of (Z)- and (E)-1,3-D, respectively. (E)-1,3-D was degraded faster than (Z)-1,3-D by the strain AS2C and the consortium. AS2C also degraded (E)-3-CAA faster than (Z)-3-CAA. Isomerization of (E)-1,3-D to (Z)-1,3-D orthe (Z) form to the (E) form did not occur.     

TAT-hEGF融合蛋白在E.coli BL21(DE3)中高效自我表达

为了获得TAT-hEGF融合蛋白在E.coliBL21(DE3)中高效表达,构建了原核表达载体pRSET-tat-hegf,将其转化E.coliBL21(DE3)得到重组工程菌BL21(DE3)/pRSET-tat-hegf。工程菌在无IPTG的诱导下实现了高效表达,TAT-hEGF融合蛋白的表达量占总菌体蛋白的45.6%,主要以包涵体形式存在。     

New Amides from Buckwheat Seeds (Fagopyrum esculentum Moench)

Two new amino acid amides which yield in acid hydrolysis isomeric hydroxybenzylamines and amino acids have been isolated from the achenes of Fagopyrum esculentum Moench. One of them called BN-II is composed of salicylamine and allo-4-hydroxy-l-glutamic acid, and the other, BN-III, p-hydroxybenzylamine and l-glutamic acid. These coupled compounds link one another to form an amide respectively. Finally the structures of BN-II and BN-III were determined to be N⁵-(2′-hydroxybenzyl)-allo-4-hydroxy-l-glutamine and N⁵-(4′-hydroxybenzyl)-l-glutamine respectively from their chemical and spectrometry properties.     

Canalization of the redbanded leafroller moth sex pheromone blend

Previous attempts to shift the (Z)-11-/(E)-11-tetradecenyl acetate ratio of pheromone components in the redbanded leafroller moth (RBLR), Argyrotaenia velutinana, by several selection protocols showed that this ratio is strongly canalized. Analysis of the complete seven-component blend, however, showed that a Geneva laboratory stock of RBLR had a lower percent (20%) of the E9–12:OAc minor component compared to the E11–14:OAc component than a population of RBLR from North Carolina (31%). Hybrid populations from these two cultures were used in a two-way family truncation selection scheme in which families were selected for either the lowest (low line) or the highest (high line) ratio of E9–12:OAc/E11–14:OAc. After three generations of selection, the low line had 14% E9–12:OAc relative to E11–14:OAc and the high line had 42%. The selection pressure was removed in generations 4–9, and the low line remained unchanged at 14% E9–12:OAc; but in the high line, it drifted to 53%. Studies were conducted to estimate heritability and realized heritability. The realized heritability calculated for each generation of selection averaged 1.14 for the low line and 1.50 for the high line. These calculations, along with estimated heritability values of 0.416 and 0.644 for reciprocal crosses, indicate some plasticity in the E9–12:OAc/E11–14:OAc ratio. This ratio was positively correlated to the total amount of 12-carbon components to 14-carbon components, but was negatively correlated to the Z/E ratio of Δ11-tetradecenylacetates. The results of two studies on the canalization of various components of the RBLR sex pheromone blend indicate that there is limited potential in this insect for manipulation of the blend ratios in the laboratory.     

浆果楝中的新木脂素

从浆果楝（Cipadessa baccifera）中分离得到两个木脂素,其化学结构通过波谱方法鉴定为：（-）-9′-O-（E）-coumarate-5,5′-dimethoxylariciresinol（1）和（＋）-9′-O-（E）-feruloyl-5,5′-dimethoxylariciresinol（2）。其中化合物1为新化合物。     

Inhibitory Effect of Coronamic Acid Derivatives on Senescence in Cut Carnation Flowers

(+)-(1R,2S)-Allocoronamic acid, (?)-(1S,2R)-allocoronamic acid, and their racemate showed an inhibitory effect on senesence in cut carnation flowers. This antisenescent activity was based on the inhibition of endogenous ethylene formation catalyzed by an ethylene-forming enzyme.     

Synthesis of (E)-9-(1-pyrenyl)-4-hydroxynon-2-enal, a fluorescent probe of the (E)-4-hydroxynon-2-enal with retained biological properties

(E)-9-(1-pyrenyl)-4-hydroxynon-2-enal (FHNE), a fluorescent probe of (E)-4-hydroxynon-2-enal (HNE) is synthesised in seven steps and in 35% overall yield, starting from commercially available 1-pyrencarboxyaldehyde. When incubated with cultured HeLa cells this fluorescent probe penetrates cells and particularly concentrates in the region surrounding the nucleus. As the parent compound, HNE it is able to induce the activation of heat shock factor (HSF) and it is able to induce the binding of HSF to heat shock element (HSE).     

中国西藏部分地区猪戊型肝炎病毒流行病学调查

戊型肝炎病毒(Hepatitis E Virus,HEV)感染是一个重要的全球公共卫生问题,而猪被认为是HEV的天然宿主。HEV可以跨种间传播,且已经证实生吃感染的猪肉会导致人感染。在中国西藏许多地区仍然有生吃猪肉、猪肝等的习惯,且不同种家畜混合饲养,极易造成HEV感染和传播。然而中国西藏地区猪HEV流行情况报道甚少。文中对中国西藏5个地区市(拉萨、日喀则、山南、那曲和昌都)猪血清进行HEV Immunoglobulin-M(Ig M)和Ig G抗体检测,并通过逆转录巢氏PCR(RT-n PCR)进行HEV RNA检测和定量RT-PCR(q RT-PCR)进行病毒拷贝计算,首次报道了藏猪血清HEV RNA阳性率。结果显示,在西藏猪中HEV有较高的流行趋势。猪血清HEV Ig M抗体阳性率高达7.6%(26/340),HEV Ig G抗体阳性率为1.8%(6/340),HEV RNA阳性率高达7.6%(26/340),血清中病毒拷贝高达1.7×107 copies/m L,而且5个地区有不同的流行趋势。结果表明西藏猪HEV感染情况严重。有关部门应加强管理,以避免人与动物之间的交叉感染和暴发。     

Zero extracellular K+ and prostaglandin E release in the guinea-pig taenia coli

Prostaglandin E release rates from isolated strips of guinea-pig taenia coli increased during exposure to zero K⁺ bathing fluid, from control values of $\text{0.78 ± 0.11}\text{ng/g}$ per min to levels as high as 29.2 ng/per min. Release rates increased for 40–50 min and then remained constant or fell despite progressive increases in intracellular sodium [Na_i⁺] or fall in intracellular potassium [K_i⁺]. Readmittance of K⁺ to the bathing solution resulted in rapid reversal of elevated prostaglandin E release rates. [Na⁺_i] and [K⁺_i] were markedly more abnormal in strips exposed to zero K⁺ for 70–201 min compared to 30-min exposures. Upon the readdition of K⁺ after long zero K⁺ exposure, the rate of prostaglandin E release fell long before [Na⁺_i] and [K⁺_i] returned to control levels. After K⁺ was readded to the bathing solution, the ion concentration of tissues exposed to zero K⁺ for 30 min returned to normal much more quickly than did those of tissues exposed for the longer time periods, yet the exponential rate constants for fall of prostaglandin E release rate after K⁺ was added were not significantly different after short or long zero K⁺ exposure. Thus there was a dissociation between the return of [Na⁺_i] and [K⁺_i] and the fall of prostaglandin E release rate to control levels. Ouabain augmented prostaglandin E release under conditions where [K⁺_i] could not fall. Addition of known neurotransmitters present in this tissue to the bathing fluid did not augment prostaglandin E release. Guinea-pig taenia coli strips that had been incubated with [³H]arachidonic acid, constantly released [³H]arachidonic acid and [³H]prostaglandin E and a prostaglandin which cochromatographed with prostaglandin E but could not be converted to prostaglandin B by alkali and was shown to be 6-ketoprostaglandin F_1α. Release of [³H]arachidonic acid and [³H]prostaglandin E plus 6-[³H]ketoprostaglandin F_1α was increased when strips were exposed to zero K⁺. Data obtained in this study suggest the augmented prostaglandin E release seen during zero K⁺ or ouabain is related to increased availability of unbound arachidonic acid at the site of cyclooxygenase in the cell. Augmented prostaglandin E release is apparently not related to alterations in intracellular electrolyte concentrations or release of known neurotransmitters.     

Convenient framework of poly functionalized (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamides via rearrangements as an efficient antibiofilm inhibitors with SAR study

A simple and one-pot approach for the synthesis of highly functionalized novel (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamide derivatives from different 2-(2′,3′,4′,9′-tetrahydro-carbazol-1′-ylidene)-propanedinitriles and aryl/heteroaryl carbaldehydes via vinylogous aldol reaction. The structures of the molecules were designated by FT-IR, ¹H NMR, ¹³C NMR studies, elemental and X-ray crystallographic analysis. The synthesized pure products have been screened for in vitro antibiofilm inhibitory activity towards antibiotic-resistant pathogenic organisms. All the synthesized compounds showed biofilm inhibition. Promisingly, the moieties 3a, 3d and 3h showed higher antibiofilm activity at biofilm inhibitory concentration (BIC) (200?μg/mL) against bacterial pathogens. Among the three moieties, 3a showed high prospective against E. coli biofilm with minimal and maximal BIC percentage of 32% (10?μg/mL) and 89% (100?μg/mL) and chosen lowest BIC for further evaluation. Also, the 3a generate ROS two fold at 1?h treatment in E. coli biofilm. The 3a exhibited no toxic effect on cell viability upto 75?μg/mL in HEK293 cell lines. The results of the present study reveal that among (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamides, (E)-2-benzylideno-6-methyl-2,3,4,9-tetrahydro-1H-carbazol-(Z)-α-carbamino-α-cyano-1-ylidene (3a) could be exploited as an excellent antibiofilm agent against carbapenem-resistant E. coli bacteria strains.     

Binding of plasminogen to Escherichia coli adhesion proteins

Immobilization of plasminogen via its lysine-binding sites is regarded as a prerequisite for its activation and function in fibrinolysis and pericellular proteolysis. In the present study, the interaction of plasminogen with fimbriae found on Escherichia coli strains causing invasive human infections was studied. Plasminogen displayed concentration-dependent and saturable binding to immobilized type 1 fimbriae and, several fold lower binding to P and S fimbriae. The binding to fimbriae was effectively inhibited by -aminocaproic acid indicating that it was mediated by the lysine-binding sites of plasminogen. Binding studies with mutated fimbriae and inhibition tests indicated that the interaction was not dependent on the lectin subunit of the fimbriae. These results indicate the existence of a novel type of host-microbe interaction which may be important in the invasion by bacteria of host tissues.     

Identification of Novel Decenoic Acids in Heated Butter

Novel decenoic acids such as (E)-4-decenoic acid and (E)- and (Z)-5-,6-decenoic acid were detected as minor components in heated butter using GC and GC/MS. The formation mechanism of these novel decenoic acids is discussed on the basis of the result of the reaction of δ-decalactone with active clay in a model experiment.     

Role of hydroperoxide lyase in white-backed planthopper (Sogatella furcifera Horváth)-induced resistance to bacterial blight in rice, Oryza sativa L.

A pre-infestation of the white-backed planthopper (WBPH), Sogatella furcifera Horváth, conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae ( Xoo ) in rice ( Oryza sativa  L.) under both laboratory and field conditions. The infestation of another planthopper species, the brown planthopper (BPH) Nilaparvata lugens Stål, did not significantly reduce the incidence of bacterial blight symptoms. A large-scale screening using a rice DNA microarray and quantitative RT-PCR revealed that WBPH infestation caused the upregulation of more defence-related genes than did BPH infestation. Hydroperoxide lyase 2 ( OsHPL2 ), an enzyme for producing C₆ volatiles, was upregulated by WBPH infestation, but not by BPH infestation. One C₆ volatile, ( E )-2-hexenal, accumulated in rice after WBPH infestation, but not after BPH infestation. A direct application of ( E )-2-hexenal to a liquid culture of Xoo inhibited the growth of the bacterium. Furthermore, a vapour treatment of rice plants with ( E )-2-hexenal induced resistance to bacterial blight. OsHPL2 -overexpressing transgenic rice plants exhibited increased resistance to bacterial blight. Based on these data, we conclude that OsHPL2 and its derived ( E )-2-hexenal play some role in WBPH-induced resistance in rice.     

Monitoring codling moth (Lepidoptera: Tortricidae) with a four‐component volatile blend compared to a sex pheromone‐based blend

Monitoring adult codling moth, Cydia pomonella (L.), is a crucial component in implementing effective integrated management programmes in apple, Malus domestica Borkhausen. Use of sex pheromone lures to track male populations has been the traditional approach, but their use in orchards treated with sex pheromone for mating disruption (MD) has been problematic. Development of kairomone and kairomone–pheromone combination lures has allowed the catch of female moths and has benefited several aspects of codling moth management through improved spray timings and action thresholds. Recently, a new four‐component volatile blend (4‐K) comprised of pear ester, (E,Z)‐2,4‐ethyl decadienoate (PE), (E)‐11 4,8‐dimethyl‐1,3,7‐nonatriene, all isomers of pyranoid linalool oxide and acetic acid (AA) has been characterized that has increased female moth catch threefold versus any previous blend. Field trapping studies were conducted to compare moth catches in traps baited with 4‐K versus the use of sex pheromone, (E,E)‐8,10‐dodecadien‐1‐ol (PH) in combination with PE and AA. Trials were conducted in orchards left either untreated, or treated with PH or PH + PE. Traps baited with 4‐K and 4‐K + PH lures caught significantly more females than traps baited with PH + PE + AA lures. Traps baited with 4‐K + PH lures caught significantly more total moths than traps baited with PH + PE + AA lures in all three orchards. Adding a PH lure to traps with the 4‐K lure did not affect female catch, but significantly increased male and total moth catches. These studies demonstrate that codling moth can be trapped effectively in apple under MD without the use of sex pheromone lures. The significant increase in female codling moth catch with the 4‐K lure suggests that efforts to improve spray timings and action threshold determinations as well as mass trapping might be enhanced with this new lure.