Histidine residues at the active site of maize δ-aminolevulinic acid dehydratase

Modification of maize δ-aminolevulinic acid dehydratase (ALAD) by diethylpyrocarbonate (DEP) caused rapid and complete inactivation of the enzyme. The inactivation showed saturation kinetics with a half inactivation time at saturating DEP equal to 0.3 min and K_DEP  0.3 mM. Substrate δ-aminolevulinic acid (ALA) and competitive inhibitor levulinic acid protected against inactivation, thereby indicating that DEP modifies the active site. The modified enzyme showed an increase in absorbance at 240 nm which was lost upon treatment with 0.8 M hydroxylamine. Most of the activity lost by DEP treatment could be restored after treatment with 0.8 M hydroxylamine. The results suggest that DEP modifies 7.4 residues/mole of the enzyme. These histidine residues are essential for catalysis by ALAD.     

Synthesis,characterization and biological studies of Schiff bases derived from heterocyclic moiety

Some new Schiff bases (H₁-H₇) have been synthesized by the condensation of 2-aminophenol, 2-amino-4-nitrophenol, 2-amino-4-methylphenol, 2-amino benzimidazole with thiophene-2-carboxaldehyde and pyrrole-2-carboxaldehyde. The structures of newly synthesized compounds were characterized by elemental analysis, FT-IR, ¹ H NMR, UV–VIS, and single crystal X-ray crystallography. The in vitro antibacterial activity of the synthesized compounds has been tested against Salmonella typhi, Bacillus coagulans, Bacillus pumills, Escherichia coli, Bacillus circulans, Pseudomonas, Clostridium and Klebsilla pneumonia by disk diffusion method. The quantitative antimicrobial activity of the test compounds was evaluated using Resazurin based Microtiter Dilution Assay. Ampicillin was used as standard antibiotics. Schiff bases individually exhibited varying degrees of inhibitory effects on the growth of the tested bacterial species. The antioxidant activity of the synthesized compounds was determined by the 1,1-diphenyl-2-picrylhydrazyl(DPPH) method. IC₅₀ value of synthesized Schiff bases were calculated and compared with standard BHA.     

手术切除与介入栓塞治疗肝癌术后复发患者的临床对比研究

目的:比较手术切除与介入栓塞治疗肝癌术后复发患者的临床疗效。方法:选择2010年6月到2011年6月本院收治的92例肝癌手术切除术后复发患者,按随机数字表法分为手术切除组和介入栓塞组,各46例。手术切除组患者给予再次切除治疗,介入栓塞组患者给予介入栓塞治疗。记录并比较两组患者治疗后1年、3年及5年的生存率。检测并比较两组患者治疗前后血清肝纤维化指标,包括血清透明质酸(HA)、层黏蛋白(LN)、人Ⅲ型前胶原(HPC-Ⅲ)及IV型胶原(IV-C)水平。检测并比较两组患者治疗前后血清白细胞(WBC)、甲胎蛋白(AFP)及癌胚抗原(CEA)水平。结果:手术切除组患者治疗后1年、3年、5年的生存率均明显高于介入栓塞组,差异均具有统计学意义(P0.05)。治疗后,介入栓塞组血清HA、LN、HPC-Ⅲ及IV-C明显高于治疗前,且均明显高于手术切除组,差异均具有统计学意义(P0.05)。两组患者治疗后血清WBC、AFP及CEA水平均明显低于治疗前,且手术切除组患者血清WBC明显高于介入栓塞组,而血清AFP、CEA水平明显低于介入栓塞组,差异均具有统计学意义(P0.05)。结论:手术切除治疗肝癌术后复发能够明显提高患者生存率,降低肝纤维化程度,改善血清AFP及CEA水平,值得在临床上推广应用。     

依那西普联合来氟米特治疗强直性脊柱炎的疗效观察及安全性分析

目的:探究依那西普联合来氟米特治疗强直性脊柱炎(AS)的疗效及安全性。方法:收集2015年1月-2016年6月间我院收治的AS患者90例,按随机数字表法分为观察组和对照组,每组各45例。观察组采用依那西普联合来氟米特治疗,对照组则单纯采用来氟米特治疗。记录两组治疗前后的晨僵时间、AS活动性指数(BASDAI)和AS测量指数(BASMI),比较两组治疗总有效率及不良反应发生情况。结果:治疗后,两组患者晨僵时间、BASDAI及BASMI较治疗前均有所下降,且观察组上述各指标均显著低于对照组,差异有统计学意义(P0.05);观察组总有效率显著高于对照组,差异有统计学意义(P0.05);治疗过程中,患者发生的主要不良反应为肝功能损伤、腹泻和过敏性皮疹,但两组不良反应发生率差异无统计学意义(P0.05)。结论:依那西普联合来氟米特可获得比较理想的疗效,且不良反应发生率较低,值得在临床上推广使用。     

Prevalence of multidrug resistance in Pseudomonas spp. isolated from wild bird feces in an urban aquatic environment

Antimicrobial resistance (AMR) has been detected in the microbiota of wildlife, yet little is known about the origin and impact within the ecosystem. Due to the shortage of nonepizootic surveillance, there is limited understanding of the natural prevalence and circulation of AMR bacteria in the wild animal population, including avian species. In this surveillance study, feces from wild birds in proximity to the River Cam, Cambridge, England, were collected and Pseudomonas spp. were isolated. Of the 115 samples collected, 24 (20.9%; 95% CI, 12.6%‒29.2%) harbored Pseudomonas spp. of which 18 (75%; 95% CI, 58%‒92%) had a multiple antibiotic resistance (MAR) index greater than 0.2. No Pseudomonas spp. isolate in this study was pansusceptible. Resistance was found among the 24 isolates against ciprofloxacin (87.5%; 95% CI, 74.3%‒100%) and cefepime (83.3%; 95% CI, 68.4%‒98.2%), both of which are extensively used to treat opportunistic Pseudomonas spp. infections. The prevalence of Pseudomonas spp. in the wild bird feces sampled during this study is greater than previous, similar studies. Additionally, their multidrug resistance profile provides insight into the potential risk for ecosystem contamination. It further highlights the importance of a One Health approach, including ongoing surveillance efforts that help to develop the understanding of how wildlife, including avifauna, may contribute and disperse AMR across the ecosystem.     

Evaluation of oil dispersion formulation of nematophagus fungus,Pochonia chlamydosporia against root-knot nematode,Meloidogyne incognita in cucumber

Root-knot nematode, Meloidogyne incognita is considered as one of the major non-insect pests of crops. The management of these root feeders becomes highly challenging due to a strong host-parasitic relationship. Pochonia chlamydosporia is a nematophagus fungus that colonizes eggs of nematodes. This study aimed to test the efficacy of P. chlamydosporia (NAIMCC-SF0039) against M. incognita. An oil dispersion formulation of P. chlamydosporia was prepared using emulsifiers and vegetable oil. This formulation had a shelf-life of 90 days (3.3 × 10⁸ CFU/mL) at room temperature (28 ± 1 °C). The inhibitory effect of oil formulation was tested against M. incognita by inoculating it on the egg mass. We found that colonization of the gelatinous matrix occurred on the third day of inoculation followed by complete egg parasitization on the seventh day. A greenhouse trial was laid out to evaluate the biocontrol potential of P. chlamydosporia in cucumber (Cucumis sativus). The results showed that the application of talc formulation of P. chlamydosporia at the rate of 1 kg per acre during planting, followed by delivery of 1 L of oil dispersion formulation through drip lines at 30-day intervals caused the highest reduction of nematode infestation. This treatment recorded 67.9 and 57.5% reduction in egg masses and soil nematode population respectively than that of control.     

Hormonal and reproductive risk factors of papillary thyroid cancer: A population-based case-control study in France

The three times higher incidence of thyroid cancer in women compared to men points to a role of female sex hormones in its etiology. However the effects of these factors are poorly understood. We analyzed the association between thyroid cancer and hormonal and reproductive factors among women enrolled in CATHY, a population-based case-control study conducted in France. The study included 430 cases of papillary thyroid cancer and 505 controls frequency-matched on age and area of residence. The odds ratios for thyroid cancer increased with age at menarche (p trend 0.05). Postmenopausal women were at increased risk, as compared to premenopausal women, particularly if menopause followed an ovariectomy, and for women with age at menopause < 55 years. In addition, use of oral contraceptives and menopausal hormone therapy reduced the association with thyroid cancer by about one third, and breastfeeding by 27%. Overall, these findings provide evidence that the risk of thyroid cancer increases with later age at menarche and after menopause, and decreases with use of oral contraceptives and menopausal hormone therapy. These findings confirm an implication of hormonal factors in papillary thyroid cancer risk, whose mechanisms need to be elucidated.     

Discovery of novel oxindole derivatives as potent α-glucosidase inhibitors

A series of 6-chloro-3-oxindole derivatives 1–25 were synthesized in high yields by the reaction of 6-chlorooxindole with different aromatic aldehydes in the presence of piperidine. All the synthesized compounds were isolated with E configuration. The structures were confirmed using spectroscopic techniques, including ¹H NMR and EIMS. These compounds showed varying degree of yeast α-glucosidase inhibition and seven were found as potent inhibitors of the enzyme. Compounds 2, 3, 4, 5, 6, 23, and 25 exhibited IC₅₀ values 2.71 ± 0.007, 11.41 ± 0.005, 37.93 ± 0.002, 15.19 ± 0.004, 24.71 ± 0.007, 17.33 ± 0.001, and 14.2 ± 0.002 μM, respectively, as compared to standard acarbose (IC₅₀, 38.25 ± 0.12 μM). Docking studies helped to find interactions between the enzyme and the active compounds. As a result of this study, oxindoles have been discovered as a new class of α-glucosidase inhibitors which have not been reported earlier.     

Morphometric analysis of the genusHemerocallis L. (Liliaceae) in Korea

To better understand the patterns of variability and distributions ofHemerocallis in Korea, 53 locations were visited and measurements of 19 morphological and phenological characters were taken on plants directly from their natural habitats. For morphometric analysis, 10 plants from each of 34 populations and five herbarium specimens ofH. middendorffii were used and the data from 12 quantitative characters was analyzed using univariate analysis. Except the littoral populations of Cheju, Hong, Taehuksan, and Sohuksan Islands (H. hongdoensis M. Chung & S. Kang), three peninsular KoreanHemerocallis species can be recognized mainly in South Korea:H. hakuunensis Nakai (=H. micrantha Nakai, growing on southern, central, and northwestern Korea);H. thunbergii Baker (=H. coreana Nakai, found on southeastern and central Korea); andH. middendorffii Tr. et Mey. (central and northeastern Korea). Morphological and phenological features contributing to recognition of the three groups were; color of perianth, shape of roots, shape of inflorescence, flowering time, odor, length of inflorescence, width of the lowest bracts, length of perianth tube enclosing a ovary, width of the inner perianth lobes. Natural hybridization seems to be rare in KoreanHemerocallis. It appears that the KoreanHemerocallis species are relatively well characterized by their distribution patterns, phenology, and habitats compared with the JapaneseHemerocallis species.     

From “Us vs. Them” to “Shared Risk”: Can Animals Help Link Environmental Factors to Human Health?

Linking human health risk to environmental factors can be a challenge for clinicians, public health departments, and environmental health researchers. While it is possible that nonhuman animal species could help identify and mitigate such linkages, the fields of animal and human health remain far apart, and the prevailing human health attitude toward disease events in animals is an “us vs. them” paradigm that considers the degree of threat that animals themselves pose to humans. An alternative would be the development of the concepts of animals as models for environmentally induced disease, as well as potential “sentinels” providing early warning of both noninfectious and infectious hazards in the environment. For such concepts to truly develop, critical knowledge gaps need to be addressed using a “shared risk” paradigm based on the comparative biology of environment–host interactions in different species.