MicroRNA-29b upregulation improves myocardial fibrosis and cardiac function in myocardial infarction rats through targeting SH2B3.

OBJECTIVE: Myocardial fibrosis (MF) seriously affects normal cardiac function. Meanwhile, MF at post-myocardial infarction (MI) is the leading cause of cardiac dysfunction in patients with acute myocardial infarction (AMI). Therefore, the aim of this study was to investigate the potential effect of microRNA-29b on MF and cardiac function after MI in rats. MATERIALS AND METHODS: In vivo MI model was constructed by ligation of the left anterior descending coronary artery in Sprague-Dawley rats. Lentivirus overexpressing microRNA-29b was established and transfected to up-regulate microRNA-29b expression in rat myocardial tissues. The effect of microRNA-29b on luciferase activity of SH2B3 3'UTR was detected by the luciferase reporter gene assay. The mRNA levels of microRNA-29b, SH1B3, COL1A1, and α-SMA in the infarct border zone and cardiomyocytes were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Meanwhile, the protein levels of SH1B3, COL1A1, and α-SMA in the MI border zone and cardiomyocytes were determined by Western blot. In addition, cardiac function and MF in MI rats were evaluated by echocardiography, hematoxylin and eosin (HE) and Masson staining, respectively. RESULTS: MicroRNA-29b expression decreased significantly in the infarct border zone at day 28 after MI (p<0.05). In addition, microRNA-29b overexpression in myocardial tissues of MI rats significantly improved impaired cardiac function, reduced collagen volume fraction and down-regulated the expressions of COL1A1 and ɑ-SMA. Subsequent luciferase reporter gene assay verified the binding relation between microRNA-29b and SH2B3. Furthermore, the expressions of COL1A1 and ɑ-SMA were confirmed negatively regulated by SH2B3. CONCLUSIONS: MicroRNA-29b overexpression alleviates MF and cardiac dysfunction in MI rats through targeting SH2B3.

Dynamic QTL analysis of protein content and glutamine synthetase activity in recombinant inbred wheat lines.

Protein content (PC) is a crucial factor that determines the end-use and nutritional quality of wheat (Triticum aestivum). Glutamine synthetase (GS), which is a major participant in nitrogen metabolism, can convert inorganic nitrogen into organic nitrogen. Although many studies have been conducted on PC and GS, a dynamic analysis of all of the filling stages has not been conducted. Therefore, 115 F9-10 recombinant inbred wheat lines of 'R131/R142' were used to analyze PC and GS activity during different developmental stages, using the conditional quantitative trait loci (QTL) mapping method. Twenty-two and six conditional QTL were detected for PC and GS activily, respectively. More QTL in leaf PC were detected during the early filling stages than in the later filling stages. Grain PC QTL displayed different dynamic variations to leaf PC QTL during the entire grain-filling stages. All of the QTL were expressed differently over time, and nine conditional QTL were detected across two filling stages. QTL with similar functions may have tended to group in specific locales. This study provides dynamic genetic information on protein accumulation during grain-filling stages.

Diversity resistance to Puccinia striiformis f. sp Tritici in rye chromosome arm 1RS expressed in wheat.

The 1BL.1RS wheat-rye translocation contained in the Russian cultivar Aurora has been the most widespread alien translocation in wheat-breeding programs all over the world. However, following the prevalence of new biotypes of the pathogens, disease-resistance genes in this translocation chromosome have been overcome and consequently they have been eliminated in modern wheat-breeding programs. In this paper, we report on 12 new primary 1BL.1RS translocation lines derived from the crosses of a Chinese high yield wheat cv. Mianyang 11 with three rye cultivars collected from China. GISH, C-banding and PCR techniques using the specific primers for 1BS, 1RS and centromeres of wheat and rye were applied to identify the constitution of chromosomes. The results confirmed that all 1BL.1RS chromosomes in the 12 primary translocation lines contained integrated 1RS chromosome arms. In the resistance analysis using five kinds of Pst pathotypes, the 12 primary translocation lines showed diversity resistance to stripe rust, which contained at least five different new genes (alleles), significantly different from the Yr9 gene coming from Russian wheat cultivar Aurora. The results indicated that the chromosome arm 1RS in the rye population carries abundant yet untapped genes (alleles) for resistance to wheat stripe rust, which would originate from the neutral diversity in the natural population of rye. It is suggested that creating more primary translocation lines in genome modification will be extremely important to use the diversity of alien R-genes, which was generated by long-term neutral mutation and maintained in the population of alien species.

Major quality trait analysis and QTL detection in hexaploid wheat in humid rain-fed agriculture.

Humid rain-fed agriculture is a special environment for wheat (Triticum aestivum) culture that tends to negatively affect wheat yield and quality. To identify quality characters of wheat in a humid environment, we conducted quality analysis and quantitative trait loci (QTL) detection in a recombinant inbred line whose parent had a high level of quality for several years. We found that high-quality wheat had less gluten content and lower protein content. Apparently, wheat quality and associated quantity traits were in a dynamic state of equilibrium. We detected 83 QTL for 10 wheat quality traits in this recombinant inbred line population. Nine QTL were detected in both evaluation years; Q.DT.scau-2A, linked to Xwmc522-2A, was detected at the same genetic location in both years. Other QTL for different traits were detected simultaneously in more than one location. Consequently, there appeared to be pleiotropic genes that control wheat quality. Based on previous studies and our research on QTL analysis of grain protein content, we conclude that there must be one or more genes for grain protein content on chromosome 6B, whose expression was little affected by environment. We constructed a consensus map and projected the QTL on it. It was useful for choosing optimal markers for marker-assisted breeding and map-based cloning.

Evolutionary trends of microsatellites during the speciation process and phylogenetic relationships within the genus Secale.

Eleven weedy or wild species or subspecies of the genus Secale L. were compared with a set of cultivated rye accessions, based on inter-simple sequence repeat (ISSR) markers to analyze their phylogenetic relationships. A total of 846 bands were amplified from reactions using 12 screening primers, including 79 loci with a mean of 10.1 alleles per locus. The number of amplified bands for each primer ranged from 12 to 134, with a mean of 70.5 amplified bands per primer. The presence and distribution of amplified bands in different accessions demonstrate that a rapid evolutionary trend of microsatellite repeats occurred during the speciation process from the perennial wild form to annual cultivated rye. In addition, variation, amplification, and deletion of microsatellites in genomes revealed phylogenetic relationships in the genus Secale. Analysis of the presence, number, and distribution of amplified bands in genomes, as well as the comparison with genetic similarity (GS) indices based on ISSR, indicate that Secale strictum subsp. africanum (Stapf) Hammer, Secale strictum anatolicum (Boiss.) Hammer, Secale sylvestre Host, and Secale strictum subsp. strictum (C. Presl) Hammer emerged in succession from a common ancestor of Secale following geographic separation and genetic differentiation. The annual weedy rye evolved from S. strictum subsp. strictum, which was domesticated as present-day cultivated rye. Data from ISSR analyses separated all investigated accessions of the genus Secale into three distinct groups. These results support the division of the genus Secale into three species: the annual wild species S. sylvestre; the perennial wild species S. strictum, including several differential subspecies forms such as strictum, africanum, and anatolicum; and S. cereale, including cultivated and weedy rye as subspecies forms.

Resistance to ciprofloxacin of respiratory pathogens in patients with cystic fibrosis.

OBJECTIVE: To determine the incidence of resistance to ciprofloxacin in respiratory pathogens isolated from patients with cystic fibrosis (CF) compared with that of isolates from patients without CF. The hypothesis was that repeated exposure of these respiratory pathogens to ciprofloxacin would reduce their sensitivity. DESIGN: Isolates of Pseudomonas aeruginosa and Staphylococcus aureus were obtained prospectively from sputa of patients with CF, as part of their routine care. The sensitivities of these isolates to ciprofloxacin were determined by standard agar dilution techniques. SETTING AND PATIENTS: The study was carried out in patients who attended the outpatient clinic or were treated as inpatients of a tertiary referral hospital. Sputa were obtained from 71 patients with CF (age range, 2-31 years) and isolates of P. aeruginosa and S. aureus were compared with those from 54 hospital patients who did not have CF. OUTCOME MEASURES: Sensitivities to ciprofloxacin, expressed as the minimal concentrations required to inhibit growth of the organisms (MIC), were used to make comparisons between different isolates and the same isolates within patients at different times. RESULTS: A higher incidence of ciprofloxacin resistance was displayed by isolates of P. aeruginosa from CF patients who had been previously prescribed ciprofloxacin (MIC50 of 2.0 mg/L and 4.0 mg/L for mucoid and non-mucoid strains respectively). The MIC of individual organisms tended to rise after a course of ciprofloxacin had been given to their host. A much lower incidence of resistance was displayed by isolates of P. aeruginosa from patients without CF (MIC50, 0.25 mg/L). Similarly, S. aureus isolates from patients with CF exhibited greater resistance to ciprofloxacin (MIC50, 32 mg/L) than isolates from other patients (MIC50, 0.75 mg/L). CONCLUSION: The resistance of P. aeruginosa appears to be related to ciprofloxacin exposure, so further development of resistance may be diminished by restricting the frequency of ciprofloxacin administration to individual patients.

Survey on use of antimicrobial agents and bacterial resistance in Huashan Hospital.

A cross-section study was carried out to assess the general patterns in use of antimicrobial agents and the trends of bacterial resistance in Huashan Hospital. Of 2,400 patients whose charts were reviewed, 61% were given such drugs. 3,596 antibiotic courses were prescribed. Gentamicin was most frequently used. Results of the susceptibility test of 320 bacterial strains showed a high percentage of resistance against gentamicin, ampicillin, and chloramphenicol. Our findings suggest that antibiotic policies in the hospital need reappraising.