Determinants of resistant starch accumulation in wheat endosperm

A part of the big three cereal crops in the world, wheat has become a major constituent of the everyday food chain and is grown at a massive scale to meet global demands. This makes it an important crop from an economic as well as food security perspective. Selection of high-quality cultivars and consistent trait enhancement for such cultivars is crucial, and in light of new challenges from climate change, this has become an absolute necessity of time. In this regard, we conducted a detailed qualitative and quantitative trait analysis for multiple commercially viable varieties of wheat, and corresponding results were subjected to a series of critical statistical analyses. Final results have shown that five cultivars including Uqaab-2000, Faisalabad- 85, Anmol-19, NARC-2009, and Pirsabak-2004 depicts higher levels of various essential qualitative and quantitative traits (including Starch content, grain weight, RS content, Protein content, etc.) and are most viable varieties for further growth and trait enhancements to meet regional and global food challenges.     

氟喹诺酮类药物体外诱导肺炎克雷伯菌耐药后GyrA和ParC的变异

目的了解3种氟喹诺酮类（FQS）体外诱导肺炎克雷伯菌（Klebsiella pneumoniae,Kpn）耐药性的差异,研究肺炎克雷伯菌DNA旋转酶A亚单位（GyrA）和拓扑异构酶ⅣC亚基（ParC）的变异与其耐喹诺酮类药物的关系。方法采用环丙沙星（CW）、左氧氟沙星（LEX）和加替沙星（GAT）对从临床分离8株Kpn进行体外分步诱导,采用琼脂平板二倍稀释法测定CIP、LVF及GAT对Kpn诱导前、后的最低抑菌浓度（MIC）,并对诱导成功的17株Kpn的GyrA的基因（gyrA）和ParC的基因（parC）进行PCR扩增,选取其中8株KpnDNA测序并进行序列分析比较。结果8株耐FQS菌株都存在GyrA变异,同FQS耐药性相关的变异有Ser83（TCC）→Phe（TTC）、Ile（ATC）和Tyr（TAC）,Asp87（GAC）→Ala（GCC）、ma（GCC）和Glu（GAA）,5株Kpn同时存在ParC的变异：丝氨酸Ser80（AGC）→Ile（ATC）。结论本研究体外实验证实了Kpn可在长期低剂量的接触抗菌药物后形成耐药菌株。在高度耐FQS的Kpn中同时存在GyrA和ParC变异。     

Genetic dissection of resistance to root-knot nematodes Meloidogyne spp. in plum, peach, almond, and apricot from various segregating interspecific Prunus progenies

Sources of resistance in Prunus spp. exhibit different spectra to the root-knot nematodes (RKN) Meloidogyne incognita, Meloidogyne javanica and Meloidogyne floridensis. In this Prunus genus, two dominant genes, Ma with a complete spectrum from the heterozygous Myrobalan plums P.2175 and P.2980 (section Euprunus; subgenus Prunophora) and RMia with a more restricted spectrum from the peaches Nemared and Shalil (subgenus Amygdalus), have been identified. This study characterizes the resistance spectra of interspecific crosses involving (1) previous Myrobalan and peach sources, (2) two Alnem almonds (subgenus Amygdalus) resistant to M. javanica, and (3) the apricot A.3923, representing a species considered RKN-resistant (section Armeniaca; Prunophora). For both latter species, genetic data could be obtained through F1 crosses with genetically characterized Myrobalans that conferred their rooting ability for clonal multiplication of the hybrids and permitted their simultaneous evaluation to the three RKN. Crosses involving either Ma or RMia or both generated the expected resistance spectra. Nemared confirmed the species-specific resistance to M. incognita conferred by RMia. This rootstock, also previously considered resistant to M. javanica, was susceptible to the M. javanica isolate used, what illustrates an isolate-specific resistance to this species. Alnem accessions were shown homozygous resistant to M. javanica. In the progeny P.2980 × A.3923, Ma markers allowed to distinguish resistant individuals carrying that gene from resistant individuals lacking it. Distribution of non-Ma individuals in this cross suggested, in the apricot parent, (1) the absence of a major gene allelic to Ma and (2) the presence of a non RKN specific polygenic resistance.     

Cardiovascular Risk of Resistant Hypertension: Dependence on Treatment-Time Regimen of Blood Pressure–Lowering Medications

In resistant hypertension, ingesting one or more blood pressure (BP)-lowering medications at bedtime is associated with significant reduction of sleep-time BP, a sensitive prognostic marker of cardiovascular disease (CVD) risk. This randomized trial investigated if bedtime therapy with at least one hypertension medication exerts better BP control and CVD risk reduction than conventional, morning-time therapy with all medications. We conducted a prospective, open-label, blinded-endpoint trial on 776 patients (387 men/389 women) with resistant hypertension, 61.6?±?11.2 (mean?±?SD) yrs of age. Patients were randomized to ingest all their prescribed hypertension medications upon awakening or ≥1 of them at bedtime. BP was measured by ambulatory monitoring for 48?h at baseline, and again annually or more frequently (quarterly) if treatment adjustment was required. After a median follow-up of 5.4 yrs (range, .5–8.5 yrs), participants ingesting ≥1 hypertension medications at bedtime showed a significantly lower hazard ratio (HR) of total CVD events (adjusted by age, sex, and diabetes) than those ingesting all medications upon awakening (.38 [95% CI: .27–.55]; number of events 102 vs. 41; p?<?.001). The difference between groups in the adjusted HR of major CVD events (a composite of CVD death, myocardial infarction, ischemic stroke, and hemorrhagic stroke) was also statistically significant (.35 [95% CI: .18–.68]; number of events 32 vs. 12; p?=?.002). At the last evaluation, patients treated with the bedtime versus awakening-time-treatment regimen showed significantly lower sleep-time systolic/diastolic BP mean values (121.6/65.4 vs. 113.0/61.1?mm Hg; p?<?.001) and higher prevalence of controlled ambulatory BP (61% vs. 46%; p?<?.001). The progressive decrease in the sleep-time systolic BP mean during follow-up was the most significant predictor of event-free survival (15% risk reduction per 5?mm Hg decreased asleep systolic BP mean). Among patients with resistant hypertension, ingestion of at least one hypertension medication at bedtime, compared with all medications upon waking, resulted in improved ambulatory BP control and fewer hard and soft CVD events. (Author correspondence: rhermida@uvigo.es)     

抗性淀粉对HFA小鼠肠道菌群的影响

目的 以人源菌群(HFA)小鼠为研究模型,观察抗性淀粉(RS)对高脂饮食诱导的肥胖小鼠肠道菌群的多样性的影响.方法 将30只无菌小鼠接种健康人志愿者的粪便悬液构建HFA小鼠模型后,随机分成3组,一组喂养含20％的抗性淀粉的高脂饲料(RS组),一组喂养纯高脂饲料(CK组),一组喂养普通饲料(CONV组),取第0周和第8周的小鼠新鲜粪便,用PCR-DGGE分析3组小鼠的肠道菌群的相似性和多样性.结果 3组小鼠在第0周时肠道菌群多样性的相似度达到79％～87％,与人的肠道菌群相似性达到39％,说明构建HFA小鼠模型成功,第8周时,3组之间的均匀度(E)和Shannon指数差异无统计学意义(P＞0.05),而丰富度(S)在高脂组(CK)与普通饲料组(CONV)和抗性淀粉组(RS)之间差异都有统计学意义(P＜0.05),说明高脂饮食引起肠道菌群多样性增加,而抗性淀粉则能降低这种多样性.结论 抗性淀粉可以显著影响HFA小鼠的肠道菌群多样性.     

一种高效构建同源重组DNA片段的方法——融合PCR

融合PCR技术（fusion PCR）采用具有互补末端的引物,形成具有重叠链的PCR产物,通过PCR产物重叠链的延伸,从而将不同来源的任意DNA片段连接起来,此技术在不需要内切酶消化和连接酶处理的条件下实现DNA片段的体外连接,为同源重组片段的构建提供了快速简捷的途径。对原有的融合PCR技术进行改进,以三个同源重组线性DNA片段的构建为例,详细论述了改进的融合PCR技术的反应过程及技术体系。结果表明,改进的融合PCR技术可以同时进行三个片段及四个片段的融合反应,产物长度均在4.5kb以上,各同源重组片段在扩增过程中均无突变发生,获得的片段可以用于后续实验分析。     

Phylogenetic diversity and mutational analysis of New Delhi Metallo-β-lactamase (NDM) producing E. coli strains from pediatric patients in Pakistan

The evolution of NDM genes (bla_NDM) in E. coli is accounted for expansive multidrug resistance (MDR), causing severe infections and morbidities in the pediatric population. This study aimed to analyze the phylogeny and mutations in NDM variants of E. coli recovered from the pediatric population. Carbapenem-resistant clinical strains of E. coli were identified using microbiological phenotypic techniques. PCR technique used to amplify the bla_NDM genes, identified on agarose gel, and analyzed by DNA sequencing. The amino acid substitutions were examined for mutations after aligning with wild types. Mutational and phylogenetic analysis was performed using Lasergene, NCBI blastn, Clustal Omega, and MEGA software, whereas PHYRE2 software was used for the protein structure predictions. PCR amplification of the bla_NDM genes detected 113 clinical strains of E. coli with the contribution of bla_NDM-1 (46%), bla_NDM-4 (3.5%), and bla_NDM-5 (50%) variants. DNA sequencing of bla_NDM variants showed homology to the previously described bla_NDM-1, bla_NDM-4, and bla_NDM-5 genes available at GenBank and NCBI database. In addition, the mutational analysis revealed in frame substitutions of Pro60Ala and Pro59Ala in bla_NDM-4 and bla_NDM-5, respectively. The bla_NDM-1 was ortholog with related sequences of E. coli available at GenBank. The phylogenetic analysis indicated that the NDM gene variants resemble other microbes reported globally with some new mutational sites.     

Restriction endonuclease resistant chromatin in human chromosomes

Summary The recent addition of restriction endonucleases in obtaining selective bands in the human genome has added a new dimension to molecular genetics. However, a considerable discrepancy exists in banding patterns produced by AluI in chromosomes 19 and 20, by MboI in chromosomes 4, 5, 8, 21 and 22 and by RsaI in chromosomes 12, 21 and 22. The principal causes of these differences are highlighted.     

Host mating system and the spread of a disease-resistant allele in a population

The model presented here modifies a susceptible-infected (SI) host–pathogen model to determine the influence of mating system on the outcome of a host–pathogen interaction. Both deterministic and stochastic (individual-based) versions of the model were used. This model considers the potential consequences of varying mating systems on the rate of spread of both the pathogen and resistance alleles within the population. We assumed that a single allele for disease resistance was sufficient to confer complete resistance in an individual, and that both homozygote and heterozygote resistant individuals had the same mean birth and death rates. When disease invaded a population with only an initial small fraction of resistant genes, inbreeding (selfing) tended to increase the probability that the disease would soon be eliminated from a small population rather than become endemic, while outcrossing greatly increased the probability that the population would become extinct due to the disease.     

Microsatellite and minisatellite markers based DNA fingerprinting and genetic diversity of blast and ufra resistant genotypes

A total of 78 alleles and 29 loci were detected from nine microsatellite and three minisatellite markers, respectively across 26 blast and ufra disease resistant genotypes. For blast resistant genotypes, the Polymorphic Information Content (PIC) values ranged from 0.280 to 0.726 and RM21 was considered as the best marker. PIC values ranged from 0.5953 to 0.8296 for ufra resistant genotypes and RM23 was the best marker for characterization of ufra resistant genotypes. The genetic similarity analysis using UPGMA clustering generated nine clusters with coefficient of 0.66 for blast resistant genotypes while five genetic clusters with similarity coefficient of 0.42 for ufra resistant genotypes. In order to develop resistant varieties of two major diseases of rice, hybridisation should be made using the parents, BR29 and NJ70507, BR36 and NJ70507 for blast, while BR11 and Aokazi, BR3 and Aokazi, Rayda and BR3 and Rayda and BR11 for ufra.