Control of glyphosate uptake and metabolism in Pseudomonas sp. 4ASW

Abstract The tandem mini-exon gene repeat is an ideal diagnostic target for trypanosomatids because it includes sequences that are conserved absolutely coupled with regions of extreme variability. We have exploited these features and the polymerase chain reaction to differentiate Phytomonas strains isolated from phloem, fruit or latex of various host plants. While the transcribed regions are nearly identical, the intergenic sequences are variable in size and content (130–332 base pairs). The mini-exon genes of these phytomonads can therefore be distinguished from each other and from the corresponding genes in insect trypanosomes, with which they are oft confused.     

Plasmodial heat shock proteins: targets for chemotherapy

Heat shock proteins act as molecular chaperones, facilitating protein folding in cells of living organisms. Their role is particularly important in parasites because environmental changes associated with their life cycles place a strain on protein homoeostasis. Not surprisingly, some heat shock proteins are essential for the survival of the most virulent malaria parasite, Plasmodium falciparum . This justifies the need for a greater understanding of the specific roles and regulation of malarial heat shock proteins. Furthermore, heat shock proteins play a major role during invasion of the host by the parasite and mediate in malaria pathogenesis. The identification and development of inhibitor compounds of heat shock proteins has recently attracted attention. This is important, given the fact that traditional antimalarial drugs are increasingly failing, as a consequence of parasite increasing drug resistance. Heat shock protein 90 (Hsp90), Hsp70/Hsp40 partnerships and small heat shock proteins are major malaria drug targets. This review examines the structural and functional features of these proteins that render them ideal drug targets and the challenges of targeting these proteins towards malaria drug design. The major antimalarial compounds that have been used to inhibit heat shock proteins include the antibiotic, geldanamycin, deoxyspergualin and pyrimidinones. The proposed mechanisms of action of these molecules and the pathways they inhibit are discussed.     

Construction and characterisation of a yeast artificial chromosome library containing five haploid sugarbeet (Beta vulgaris L.) genome equivalents

A yeast artificial chromosome (YAC) genomic library of Beta vulgaris was constructed in the pYAC4 vector. High-molecular-weight DNA was prepared from agarose-embedded leaf protoplasts from a triploid cultivar. The library was found to contain 33,500 clones in an ordered array of microtiter plates. Mean size of the inserts was estimated to be 135 kb, and the library should therefore represent the equivalent of five haploid genomes. The library was characterised for the presence of highly repetitive, chloroplast and single-copy sequences. In order to isolate single-copy sequences, 18 pools of DNA, each from 1920 individual YAC clones, were prepared for rapid screening of the library by the polymerase chain reaction. The results of these screenings showed that the number of isolated clones was at or near the frequency expected.     

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.     

陆地棉品种抗黄萎病反应规律的研究

对我国自育的108个陆地棉品种的抗黄萎病性进行了研究。在黄萎病发病期内,对黄萎病发病情况进行连续调查,测定产量、考查产量因素并检测纤维品质。利用因子分析法对陆地棉抗黄萎病反应规律进行分析,得出不同时期的黄萎病病指主要与前后3～5个阶段抗病性有关。病情发展主要由4个主因子决定,且第1、2主因子具有较大的方差贡献率。第1主因子(F1)主要与品种7月26日至8月9日的黄萎病病指有关,第2主因子(F2)主要与品种8月20日至9月4日的黄萎病病指有关。利用因子分析结果将108个品种划分为4个类型,前期抗病性较好而后期发病较快的第Ⅰ类品种,其产量较低,单株结铃数、单铃重、衣分均低于其他3类;纤维品质均较差,纤维长度、整齐度、比强度和马克隆值均较其他3类差。前期和后期病指均较低、发病缓慢的第Ⅱ类则小区产量最高,纤维品质处于平均水平。第Ⅲ类品种前期发病较慢,中期发病较快,具有较高的小区产量,单铃重最高;纤维整齐度、比强度和伸长率好于其他3类品种;前期发病较快,中期发病平缓,后期仍具有较高病指的为第Ⅳ类品种,小区产量较低,单株产量、单株结铃数和衣分较高;其他性状处于中等水平。但研究表明,某一阶段具有的抗病性并不能完全代表品种的抗病性。     

清热化痰、宣肺解痉法治疗支气管哮喘的临床疗效及对气道呼吸参数、生活质量的影响

摘要 目的：探讨清热化痰、宣肺解痉法治疗支气管哮喘的临床疗效及对气道呼吸参数、生活质量的影响。方法：选取我院2019年10月到2021年9月收治的60例支气管哮喘患者作为研究对象,分为观察组与对照组,每组30例。对照组予吸入布地奈德福莫特罗粉吸入剂,观察组在对照组基础上增加清热化痰宣肺解痉法治疗,对比两组患者临床疗效,治疗前与治疗1个月后的中医证候积分变化,气道呼吸参数变化,炎症因子以及生活质量变化。结果：观察组总有效率较对照组高（P<0.05）;两组患者治疗前中医证候积分对比无差异（P＞0.05）,治疗后降低,且观察组低于对照组（P＜0.05）;两组患者治疗前第1秒用力呼气容积（FEV₁）、用力肺活量（FVC）、第1s用力呼气量/用力肺活量（FEV₁/FVC）最大呼气流速（PEF）对比无明显差异（P＞0.05）,治疗后两组患者FVC、FEV₁、FEV₁/ FVC、PEF均有提升,且观察组高于对照组（P＜0.05）;两组患者治疗前肿瘤坏死因子-α（TNF-α）、转化生长因子-β1（TGF-β1）、基质金属蛋白-9（MMP-9）、血管内皮生长因子（VEGF）、干扰素-γ（IFN-γ）、白细胞介素-4（IL-4）水平对比无明显差异（P＞0.05）,治疗后两组患者TNF-α、TGF-β1、MMP-9、VEGF、IFN-γ、IL-4水平均明显降低,且观察组低于对照组（P＜0.05）;两组患者治疗前生活质量评分对比无差异（P＞0.05）,治疗后1个月生活质量相关评分均降低,且观察组较对照组低（P＜0.05）。结论：支气管哮喘患者在常规西医治疗基础上增加清热化痰宣肺解痉法治疗可减轻患者症状。另外可改善患者呼吸功能,降低炎症因子反应,提升患者生活质量。     

龈沟液炎性因子及TSP-1在拔牙正畸患者中的表达情况及发生牙周疾病的影响因素分析

摘要 目的：探讨龈沟液炎性因子及TSP-1在拔牙正畸患者中的表达情况及发生牙周疾病的影响因素。方法：选取我院2020年8月到2023年8月收治的80例拔牙正畸治疗患者进行回顾性分析,分别取所有患者正畸前、正畸后1个月、3个月及正畸结束时的龈沟液样本检测肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、血小板反应蛋白-1（TSP-1）表达水平。随后依照患者正畸治疗过程中是否患有牙周疾病将其分为牙周疾病组（n=36）及非牙周疾病组（n=44）,对比两组患者正畸前及正畸结束时的TNF-α、IL-1β、IL-6、TSP-1表达水平,对比两组患者一般情况,采用logistics回归模型分析拔牙正畸患者牙周疾病的影响因素。结果：80例拔牙正畸患者中正畸后1个月、3个月 TNF-α、IL-1α、IL-6、TSP-1水平升高,正畸后3个月到正畸结束时TNF-α、IL-1β、IL-6、TSP-1水平趋于平稳,但正畸后1个月、3个月及结束时明显高于正畸前（P＜0.05）;牙周疾病组与非牙周疾病组患者正畸前、正畸后TNF-α、IL-1β、IL-6、TSP-1表达水平对比差异显著,牙周疾病组明显高于非牙周疾病组（P＜0.05）;牙周疾病组及非牙周疾病组患者性别、年龄、BMI对比无明显差异（P＞0.05）,牙周疾病组及非牙周疾病组患者正畸治疗时间、拔牙数量、正畸方式、口腔清洁度对比差异显著（P＜0.05）;logistic回归分析结果表明：TNF-α、IL-1β、IL-6、TSP-1、正畸方式、口腔清洁度为拔牙正畸患者牙周疾病的独立危险因素（P＜0.05）。结论：拔牙正畸患者随着正畸时间延长龈沟液炎性因子及TSP-1水平明显升高,且TNF-α、IL-1β、IL-6、TSP-1、正畸方式、口腔清洁度为拔牙正畸患者牙周疾病的独立危险因素。     

Transesterification catalyzed by polystyrene-supported chymotrypsin in toluene: the effect of neutralization of basic or acidic groups attaching to polystyrene resins

Crosslinked polystyrene resins containing a low level of either basic or acidic groups were used for supports of alpha-chymotrypsin (CT), which catalyzed the transesterification of N-acetyl-L-phenylalanine ethyl ester (AcPheOEt) with propanol in toluene. With a minimal amount of water, CT was sorbed to the resins, basic or acidic groups of which were partly or fully neutralized by several soluble acids or bases. With an increasing degree of neutralization of basic resins by free acids, the rate of disappearance of AcPheOEt was decreased, whereas the by-product formation of AcPheOH, due to hydrolysis, was considerably suppressed, compared with the ester-exchange product, AcPheOPr. The pK(a) value of the neutralizing acid was also important for both CT activity and reaction selectivity. AcPheOPr was selectively produced at a certain range of pK(a) values. On the other hand, the neutralization of acidic resins with free amines enhanced the CT activity but a strong base promoted the formation of hydrolysis product. (c) 1995 John Wiley & Sons, Inc.     

A rapid PCR-based method for genetically mapping ESTs

A simple, semi-automatable procedure was developed for converting expressed sequence tags (ESTs) into mappable genetic markers. The polymerase chain reaction is used to amplify regions immediately 5′ or 3′ to the coding regions of genes in order to maximise sequence variability between alleles. Fragment length and nucleotide substitution polymorphisms among amplified alleles can be detected using either ethidium bromide staining or automated laser-based fluorescence. A 6% non-denaturing acrylamide gel, analysed with an ABI 377 DNA sequencer, proved capable of resolving homoduplexes and heteroduplexes formed between amplified alleles containing nucleotide substitutions as well as resolving allelic length differences. With this approach 75% of 60 ESTs from a range of Pinus species could be genetically mapped in each of three pedigrees from P. radiata and P. taeda. Furthermore, three or four alleles were detected in each pedigree for 42% of the EST markers. Received: 4 January 2000 / Accepted: 26 May 2000