The Gram-negative phytopathogen Xanthomonas campestris pv. campestris employs a 5'UTR as a feedback controller to regulate methionine biosynthesis.

The synthesis of methionine is critical for most bacteria. It is known that cellular methionine has a feedback effect on the expression of met genes involved in de novo methionine biosynthesis. Previous studies revealed that Gram-negative bacteria control met gene expression at the transcriptional level by regulator proteins, while most Gram-positive bacteria regulate met genes at post-transcriptional level by RNA regulators (riboregulators) located in the 5'UTR of met genes. However, despite its importance, the methionine biosynthesis pathway in the Gram-negative Xanthomonas genus that includes many important plant pathogens is completely uncharacterized. Here, we address this issue using the crucifer black rot pathogen Xanthomonas campestris pv. campestris (Xcc), a model bacterium in microbe-plant interaction studies. The work identified an operon (met) involved in de novo methionine biosynthesis in Xcc. Disruption of the operon resulted in defective growth in methionine-limited media and in planta. Western blot analysis revealed that the expression of the operon is dependent on methionine levels. Further molecular analyses demonstrated that the 5'UTR, but not the promoter of the operon, is involved in feedback regulation on operon expression in response to methionine availability, providing an example of a Gram-negative bacterium utilizing a 5'UTR region to control the expression of the genes involved in methionine biosynthesis.

Integrative Analysis of the Microbiome and Metabolome of Broiler Intestine: Insights into the Mechanisms of Probiotic Action as an Antibiotic Substitute.

Antibiotic substitutes have become a research focus due to restrictions on antibiotic usage. Among the antibiotic substitutes on the market, probiotics have been extensively researched and used. However, the mechanism by which probiotics replace antibiotics remains unclear. In this study, we aimed to investigate this mechanism by comparing the effects of probiotics and antibiotics on broiler growth performance and intestinal microbiota composition. Results shown that both probiotics and antibiotics increased daily weight gain and reduced feed conversion rate in broilers. Analysis of ileum and cecum microorganisms via 16S rRNA gene sequencing revealed that both interventions decreased intestinal microbial diversity. Moreover, the abundance of Bacteroides increased in the mature ileum, while that of Erysipelatoclostridium decreased in the cecum in response to both probiotics and antibiotics. The main metabolites of probiotics and antibiotics in the intestine were found to be organic acids, amino acids, and sugars, which might play comparable roles in growth performance. Furthermore, disaccharides and trisaccharides may be essential components in the ileum that enable probiotics to replace antibiotics. These findings provide important insights into the mechanisms underlying the use of probiotics as antibiotic substitutes in broiler breeding.

Flavor Components Comparison between the Neck Meat of Donkey, Swine, Bovine, and Sheep.

Donkey in China is well known for its draft purpose and transportation; however, donkey meat has attracted more and more consumers in recent years, yet it lacks sufficient information on its flavor components compared to other main meats. Therefore, in this study, volatile flavor compounds in neck meat of donkey, swine, bovine, and sheep were classified by electronic nose, then confirmed and quantified by gas chromatography-mass spectrometry. High-performance liquid chromatography (HPLC) and gas chromatography were used to quantify free fatty acid, amino acid, and flavor nucleotide. A total of 73 volatile compounds were identified, and aldehydes were identified as the characteristic flavor compounds in neck meat of donkey, bovine, swine and sheep in proportion of 76.39%, 46.62%, 31.64%, and 35.83%, respectively. Particularly, hexanal was the most abundant volatile flavor. Compared with other neck meat, much higher unsaturated free fatty acids were present in donkeys. Furthermore, neck meat of donkeys showed essential amino acid with highest content. Thus, special flavor and nutrition in donkey neck meat make it probably a candidate for consumers in other regions besides Asia.

A SAM-I riboswitch with the ability to sense and respond to uncharged initiator tRNA.

All known riboswitches use their aptamer to senese one metabolite signal and their expression platform to regulate gene expression. Here, we characterize a SAM-I riboswitch (SAM-IXcc) from the Xanthomonas campestris that regulates methionine synthesis via the met operon. In vitro and in vivo experiments show that SAM-IXcc controls the met operon primarily at the translational level in response to cellular S-adenosylmethionine (SAM) levels. Biochemical and genetic data demonstrate that SAM-IXcc expression platform not only can repress gene expression in response to SAM binding to SAM-IXcc aptamer but also can sense and bind uncharged initiator Met tRNA, resulting in the sequestering of the anti-Shine-Dalgarno (SD) sequence and freeing the SD for translation initiation. These findings identify a SAM-I riboswitch with a dual functioning expression platform that regulates methionine synthesis through a previously unrecognized mechanism and discover a natural tRNA-sensing RNA element. This SAM-I riboswitch appears to be highly conserved in Xanthomonas species.

[Gene polymorphism of the endothelial nitric oxide synthase enzyme and pulmonary hypertension in patient with chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the relationship between the gene polymorphism of the endothelial nitric oxide synthase enzyme (eNOSG894T) with pulmonary hypertension of Chinese patient with chronic obstructive pulmonary disease (COPD). METHODS: Fifty normal volunteers (29 male, 21 female, mean age 67 +/- 3) and 50 patients with COPD complicated by pulmonary hypertension (31 male, 19 female, mean age 69 +/- 10) were included in the study. Lung function, arterial blood gases, and echocardiographic examination were performed. The genotype of eNOSG894T was determined with PCR. RESULTS: The frequencies of GT + FT genotype and T allele were significantly greater in the patients compared to the controls. The levels of NOx and NOx/ET were lower in the GT + T genotype [(48 +/- 8) micromol/L, (0.51 +/- 0.20)] than in the GG genotype [(60 +/- 24) micromol/L, (1.43 +/- 0.64)] of COPD. The level of ET was higher in the GT + TT genotype [(104 +/- 38) microg/L] than in the GG genotype [(50 +/- 26) microg/L] of COPD patients. The mean systolic pulmonary artery pressure was higher in the GT + TT genotype [(57 +/- 15) mm Hg, 1 mm Hg = 0.133 kPa] than in the GG genotype [(47 +/- 10) mm Hg] of COPD patients. In stepwise logistic regression analysis for predicting pulmonary artery pressure, the polymorphism of eNOS gene, the level of Nox and smoking were found to be independent variables. CONCLUSION: The G894T polymorphism of eNOS gene is associated with pulmonary hypertension of COPD in a Chinese population. T allele may be involved in the etiology of pulmonary hypertension with COPD by reducing NO release of the endothelium.

Observation of influences of mental health promotion and mental intervention on mental health status of professionals.

OBJECTIVE: To observe the influences of mental health promotion and mental intervention on mental health status of professionals. METHOD: 2878 professionals for physical examination were selected and randomly divided into treatment group and control group, with 1443 professionals and 1435 professionals, respectively. Then, the difference of mental health status before and after mental intervention between two groups was compared. RESULTS: In treatment group, the proportion of people with healthy mental and modest pressure after mental intervention was higher than that before mental intervention and that in control group after mental intervention (P<0.01); the proportion of people with psychological sub-heath and moderate pressure after mental intervention was significantly lower than that before mental intervention and that in control group after mental intervention (P<0.05). There was no significant difference in mental health status in control group before and after mental intervention (P>0.05). Mental health consciousness, health status, self pressure-relief capability, job satisfaction, and happiness index of professionals were up to 63.3%~78.8%. CONCLUSIONS: Mental health promotion and mental intervention may significantly improve mental health status of professionals.

Prevalence and associated factors of corneal blindness in Ningxia in northwest China.

AIM: To describe the prevalence and demographic characteristics of corneal blindness in an urban and rural region of Ningxia, located in the northwest part of China. METHODS: A stratified, randomized sampling procedure was employed in the study, including urban and rural area of all age group. Visual acuity, anterior segment and ocular fundus were checked. Related factor of corneal disease, including age, gender, education status, ethnic group, location and occupation, were identified according to uniform customized protocol. An eye was defined to be corneal blindness if the visual acuity was <20/400 due to a corneal disease. RESULTS: Three thousand individuals (1290 from urban area and 1710 from rural area) participated in the investigation, with a response rate of 80.380%. The prevalence of corneal blindness was 0.023% in both eyes and 0.733% in at least one eye. The blindness in at least one eye with varied causes was present in 106 participants (3.533%) and in bilateral eyes in 34 participants (1.133%). The corneal diseases accounted for 20.754% of blindness in at least one eye and 20.588% of bilateral blindness. The prevalence of corneal disease was higher in older and Han ethnic group, especially those who occupied in agriculture and outdoor work. People with corneal blindness were more likely to be older and lower education. Rural population were more likely to suffer from bilateral corneal blindness than the urban population in ≥59-year group (χ (2)=6.716, P=0.019). Infectious, trauma and immune corneal disease were the three leading causes of corneal disease. Trauma corneal disease was more likely leading to blindness in one eye. However, infectious and immune corneal diseases make more contribution to the bilateral corneal blindness. CONCLUSION: Corneal blindness is a significant burden of in Ningxia population, encompassing a variety of corneal infections and trauma; the majority of those were avoidable. Health promotion strategies and good hygienic conditions have to be developed.

Identification of a novel p.R1443W mutation in RP1 gene associated with retinitis pigmentosa sine pigmento.

AIM: To screen mutations in the retinitis pigmentosa 1 (RP1) gene and the rhodopsin (RHO) gene in Chinese patients with retinitis pigmentosa sine pigmento (RPSP) and describe the genotype-phenotype relationship of the mutations. METHODS: Twenty affected, unrelated Chinese individuals with RPSP (4 autosomal dominant RPSP, 12 autosomal recessive RPSP and 4 unknown inheritance pattern) were recruited between 2009 and 2012. The clinical features were determined by complete ophthalmologic examinations. Polymerase chain reaction (PCR) and direct DNA sequencing were used to screen the entire coding region and splice junctions of the RP1 gene and the RHO gene. The cosegregation analysis and population frequency studies were performed for patients with identified mutations. RESULTS: Five variants in the RP1 gene and one in the RHO gene were detected in 20 probands. Four missense changes (rs444772, rs446227, rs414352, rs441800) and one non-coding variant (rs56340615) were common SNPs and none of them showed a significant relationship with RPSP. A missense mutation p.R1443W was identified in the RP1 gene in three affected individuals from a family with autosomal dominant RPSP and was found to cosegregate with the phenotype in this family, suggestive of pathogenic. In addition, population frequency analysis showed the p.R1443W mutation was absent in 300 healthy controls. CONCLUSION: The identification of p.R1443W mutation cosegregating in a family with autosomal dominant RPSP highlights an atypical phenotype of the RP1 gene mutation, while RHO gene is not associated with the pathogenesis of RPSP in this study. To our knowledge, this is the fist mutation identified to associate with RPSP.

MTORC1 regulates cardiac function and myocyte survival through 4E-BP1 inhibition in mice.

Mechanistic target of rapamycin (MTOR) plays a critical role in the regulation of cell growth and in the response to energy state changes. Drugs inhibiting MTOR are increasingly used in antineoplastic therapies. Myocardial MTOR activity changes during hypertrophy and heart failure (HF). However, whether MTOR exerts a positive or a negative effect on myocardial function remains to be fully elucidated. Here, we show that ablation of Mtor in the adult mouse myocardium results in a fatal, dilated cardiomyopathy that is characterized by apoptosis, autophagy, altered mitochondrial structure, and accumulation of eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). 4E-BP1 is an MTOR-containing multiprotein complex-1 (MTORC1) substrate that inhibits translation initiation. When subjected to pressure overload, Mtor-ablated mice demonstrated an impaired hypertrophic response and accelerated HF progression. When the gene encoding 4E-BP1 was ablated together with Mtor, marked improvements were observed in apoptosis, heart function, and survival. Our results demonstrate a role for the MTORC1 signaling network in the myocardial response to stress. In particular, they highlight the role of 4E-BP1 in regulating cardiomyocyte viability and in HF. Because the effects of reduced MTOR activity were mediated through increased 4E-BP1 inhibitory activity, blunting this mechanism may represent a novel therapeutic strategy for improving cardiac function in clinical HF.

Mechanism for induction of hydroxyurea resistance and loss of latent EBV genome in hydroxyurea-treated Burkitt's lymphoma cell line Raji.

Hydroxyurea (HU), as an inhibitor of ribonucleotide reductase (RR) through interaction with the R2 component, has been used in the treatment of malignancies. Recently, therapeutic strategies in Epstein-Barr Virus (EBV)-targeted lymphoma have been reported. In order to study the effect of HU on EBV, infected Burkitt's lymphoma (BL) Raji cells were passaged in medium containing 50 microM HU for more than 2 months. EBV DNA was eliminated in about 40% of the cells in the HU-treated cultures. The cells were cloned from such cultures, and only EBV-positive clones could be isolated in 102 examined clones. No differences were observed in the EBV-latent state, EBV-gene expression, or cell growth between HU-untreated Raji cells and HU-treated clones. However, relative to parental Raji cells, the HU-treated Raji clones were almost eight times resistant to growth inhibition by HU according to the ID50 value, and the expression of the R2 component of RR increased more than two to three times. These results indicate that HU not only efficiently eliminates the EBV genome from Raji cells but also induces HU resistance. HU resistance was accompanied by over-expression of the R2 component of RR. However, the HU-resistant clones were sensitive to gemcitabine, another inhibitor of RR, and this seems highly relevant to chemotherapeutic combination in the use of these drugs.

[Clinical study of subcutaneous administration of gonadotropin-releasing hormone agonist every six weeks in girls with idiopathic central precocious puberty].

OBJECTIVE: Gonadotropin-releasing hormone agonist (GnRHa) is widely used for the treatment of precocious puberty, but there was no identical regime for the dosage and the interval of administration. The aim of this study was to assess the feasibility of subcutaneous administration of Triptorelin with a prolonged interval (six weeks) for the suppression of pituitary-gonadal axis and clinical signs in girls with idiopathic central precocious puberty (ICPP). METHODS: Forty-six girls with ICPP were enrolled in this trial and were divided into two groups at random, with 26 patients in group A and 20 in group B. There were no significantly differences in chronological age, height, weight, age at clinical onset of puberty and bone age between the two groups before treatment. Triptorelin (Decapeptyl, 3.75 mg) was administered subcutaneously (SC) at 6 weeks intervals in group A or intramuscularly (IM) at 4 weeks intervals in group B. Both forms were given for more than 12 months consecutively. During the period of treatment, the clinical parameters including height, weight, pubertal stage, bone age, uterine volume and ovarian size were documented. The serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol (E(2)) were monitored using immunoenzymometric assay. RESULTS: Both treatment regimes can completely suppressed the pituitary-gonadal axis. The clinical signs of pubertal development regressed or stabilized in all patients. Breast developments, as reflected by Tanner staging, were regressed. Uterine volume decreased after treatment, however, this decrease did not reach statistical significance. Mean ovarian volume did not change significantly during treatment. The height velocity was significantly decreased from a pretreatment value of 6.3 +/- 1.4 cm/year to 5.8 +/- 1.2 cm/year in group A and 6.7 +/- 1.3 cm/year to 5.4 +/- 1.0 cm/year in group B, respectively. The rate of skeletal maturation was reduced significantly during treatment. The ratio of bone age/chronological age was 1.2 +/- 0.2 or 1.3 +/- 0.3 at the onset of therapy and decreased significantly after the treatment to 0.7 +/- 0.2 or 0.9 +/- 0.1, respectively. The predicted adult height increased significantly and progressively during therapy. The levels of serum LH, FSH and E(2) were returned to the prepubertal condition after 6 - 8 weeks treatment and remained suppressed for the duration of treatment. No significantly side effects of therapy were noted. The most common adverse event during SC treatment was that a non-irritating, 1 cm in diameter mass can be palpated at the site of subcutaneous injection in the abdominal wall of group A patients. It gradually decreased in size, and disappeared after 8 - 12 weeks. Two girls had minimal withdrawal virginal bleeding episodes after the first injection. CONCLUSION: Both IM and SC triptorelin administration were clinically effective. They can induce profound suppression of hypothalamic-pituitary-gonadal axis while stabilizing height velocity, slowing bone maturation and increasing predicted adult height. These results suggest that subcutaneous injection of triptorelin in 6 weeks intervals at a dosage of 3.75 mg was a safe and acceptable regime for ICPP with good efficacy.