Bradyrhizobium arachidis mediated enhancement of (oxy)matrine content in the medicinal legume Sophora flavescens

Effect of rhizobial inoculation and nitrate application on the content of bioactive compounds in legume plants is an interesting aspect for interactions among microbes, plants and chemical fertilizers, as well as for cultivated practice of legumes. In this study, nitrate (0, 5 and 20 mmol l⁻¹) and Bradyrhizobium arachidis strain CCBAU 051107^T were applied, individually or in combination, to the root rhizosphere of the medicinal legume Sophora flavescens Aiton (SFA). Then the plant growth, nodulation and active ingredients including (oxy)matrine of SFA were determined and compared. Rhizobial inoculation alone significantly increased the numbers and fresh weight of root nodules. Nodulation was significantly inhibited due to nitrate (5 and 20 mmol l⁻¹). Only oxymatrine was detected in the control plants without rhizobial inoculation and nitrate supplement, while both oxymatrine and matrine were synthesized in plants treated with inoculation of B. arachidis or supplied with nitrate. The content of oxymatrine was the highest in plants inoculated solely with rhizobia and was not significantly altered by additional application of nitrate. Combinations of B. arachidis inoculation and different concentrations of nitrate did not significantly change the concentrations of (oxy)matrine in the plant. In conclusion, sole rhizobial inoculation was the best approach to increase the contents of key active ingredients oxymatrine and matrine in the medicinal legume SFA.     

The Evolutionary Dynamics of Genetic Incompatibilities Introduced by Duplicated Genes in Arabidopsis thaliana

Although gene duplications provide genetic backup and allow genomic changes under relaxed selection, they may potentially limit gene flow. When different copies of a duplicated gene are pseudofunctionalized in different genotypes, genetic incompatibilities can arise in their hybrid offspring. Although such cases have been reported after manual crosses, it remains unclear whether they occur in nature and how they affect natural populations. Here, we identified four duplicated-gene based incompatibilities including one previously not reported within an artificial Arabidopsis intercross population. Unexpectedly, however, for each of the genetic incompatibilities we also identified the incompatible alleles in natural populations based on the genomes of 1,135 Arabidopsis accessions published by the 1001 Genomes Project. Using the presence of incompatible allele combinations as phenotypes for GWAS, we mapped genomic regions that included additional gene copies which likely rescue the genetic incompatibility. Reconstructing the geographic origins and evolutionary trajectories of the individual alleles suggested that incompatible alleles frequently coexist, even in geographically closed regions, and that their effects can be overcome by additional gene copies collectively shaping the evolutionary dynamics of duplicated genes during population history.     

Six New Families of Aerobic Arsenate Reducing Bacteria: Leclercia,Raoultella, Kosakonia,Lelliottia, Yokenella,and Kluyvera

Elevated levels of arsenate can occur in the environment due to processes such as mining activities, and microbes must utilize various detoxification mechanisms to adapt to the associated pressure. The aim of this study was to identify as many aerobic arsenate-reducing bacteria (aARB) as possible in order to investigate their phylogenetic diversity and molecular mechanisms of arsenic resistance. We isolated 24 strains of aARB from a long-standing arsenic contaminated environment and detected the ars genotype in them. All 24 strains could reduce approximately 90% of arsenate, and 23 of them exhibited (6–59%) arsenic removal ability. The 16S rRNA gene analyses revealed aARB representing 16 genera were abundant. The included six genera, namely Leclercia, Raoultella, Kosakonia, Lelliottia, Yokenella, and Kluyvera, that were not previously known to reduce or exhibit resistance to arsenic. Twenty-one of 24 aARB were positive for ars amplification and 17 of them harbored a putative arsC gene, which is well-known for its involvement in arsenate reduction. However, the arsenic resistance associated with aARB strains is not always determined by the ars operon system. These results have provided additional insight into aARB and their potential for arsenic transformation and bioremediation.     

Serum metabolic profiling and features of papillary thyroid carcinoma and nodular goiter

Thyroid carcinoma is a common endocrine malignancy worldwide, accounting for approximately 1% of all diagnosed cancers and about 91.5% of the malignancies of head and neck. However, differentiating malignant thyroid nodules from benign ones remains a diagnostic challenge. Thus, novel molecular markers that enable non-invasive diagnostics for malignant thyroid nodules are urgently needed. In the present study, a metabonomic investigation based on liquid chromatography-LTQ Orbitrap mass spectrometry was employed for serum metabolic profiling of 30 cases of papillary thyroid carcinomas (PTC), 80 cases of nodular goiters (benign thyroid nodules) and 30 cases of healthy controls. According to the results of multivariate statistical data analysis, the significantly changed metabolites among these three groups were defined. It was found that most of these metabolites decreased in the sera of both malignant and benign thyroid cases due to the increased metabolic rate, which is in accordance with clinical features. The major metabolic differences between benign and malignant nodules occurred in lipid metabolism. Especially, the content of 3-hydroxybutyric acid, an intermediate product of fatty acid metabolism, was much higher in the PTC group than that in the nodule goiter and control groups, indicating its potential as a diagnostic marker for PTC and nodular goiters. These results show that the serum metabolic profiling method is a powerful tool for distinguishing thyroid carcinoma from nodular goiter and healthy controls.     

Activation of Akt/mTOR Pathway Is Associated with Poor Prognosis of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumor of the head and neck region, which frequently occurs in Southeast Asia, especially in the south of China. It is known that the mammalian target of rapamycin (mTOR) pathway plays a central role in regulating cellular functions, including proliferation, growth, survival, mobility, and angiogenesis. Aberrant expression of the mTOR signaling pathway molecules has been found in many types of cancer. However, whether the alterations of p-Akt, p-p70S6K and p-4EBP1 protein expression are associated with clinicopathological features and prognostic implications in NPC have not been reported. The purposes of the present study are to investigate the association between the expression of p-Akt, p-p70S6K and p-4EBP1 proteins and clinicopathological features in NPC by immunohistochemistry. The results showed that the positive percentage of p-Akt, p-p70S6K and p-4EBP1 proteins expression in NPC (47.2%, 73.0% and 61.7%, respectively) was significantly higher than that in the non-cancerous nasopharyngeal control tissue (33.3%, 59.1% and 47.0%, respectively). There was a significantly higher positive expression of p-Akt in undifferentiated non-keratinizing nasopharyngeal carcinoma than that in differentiated non-keratinizing nasopharyngeal carcinoma (P = 0.014). Additionally, positive expression of p-p70S6K and p-4EBP1 proteins, and positive expression of either of p-Akt, p-p70S6K and p-4EBP1 were significantly correlated inversely with overall survival rates of NPC patients (P = 0.023, P = 0.033, P = 0.008, respectively). Spearman’s rank correlation test showed that expression of p-Akt in NPC was significantly associated with expression of p-p70S6K (r = 0.263, P<0.001) and p-4EBP1(r = 0.284, P<0.001). Also there was an obviously positive association between expression of p-p70S6K and p-4EBP1 proteins in NPC (r = 0.286, P<0.001). Multivariate Cox regression analysis further identified positive expression of p-4EBP1 and p-p70S6K proteins were the independent poor prognostic factors for NPC (P = 0.043, P = 0.027, respectively). Taken together, high expression of p-p70S6K and p-4EBP1 proteins may act as valuable independent biomarkers to predict a poor prognosis of NPC.     

Donor-host mitochondrial compatibility improves efficiency of bovine somatic cell nuclear transfer

Background  

The interaction between the karyoplast and cytoplast plays an important role in the efficiency of somatic cell nuclear transfer (SCNT), but the underlying mechanism remains unclear. It is generally accepted that in nuclear transfer embryos, the reprogramming of gene expression is induced by epigenetic mechanisms and does not involve modifications of DNA sequences. In cattle, oocytes with various mitochondrial DNA (mtDNA) haplotypes usually have different ATP content and can further affect the efficiency of in vitro production of embryos. As mtDNA comes from the recipient oocyte during SCNT and is regulated by genes in the donor nucleus, it is a perfect model to investigate the interaction between donor nuclei and host oocytes in SCNT.