MicroRNA‐29b‐3p suppresses oral squamous cell carcinoma cell migration and invasion via IL32/AKT signalling pathway

Oral squamous cell carcinoma (OSCC) is aggressive accompanied with poor prognosis. We previously isolated the most invasive cells resembling the invasive tumour front by microfluidic technology and explored their differentially expressed microRNAs (miRNAs) in our previous work. Here, we verified the miR‐29b‐3p as a guarder that suppressed migration and invasion of OSCC cells and was down‐regulated in the most invasive cells. Besides that, the invasion suppression role of miR‐29b‐3p was achieved through the IL32/AKT pathway. Thus, miR‐29b‐3p and IL32 might serve as therapeutic targets for blocking the progression and improving the outcome of OSCC.     

Complete Plastid Genome of the Brown Alga Costaria costata (Laminariales,Phaeophyceae)

Costaria costata is a commercially and industrially important brown alga. In this study, we used next-generation sequencing to determine the complete plastid genome of C. costata. The genome consists of a 129,947 bp circular DNA molecule with an A+T content of 69.13% encoding a standard set of six ribosomal RNA genes, 27 transfer RNA genes, and 137 protein-coding genes with two conserved open reading frames (ORFs). The overall genome structure of C. costata is nearly the same as those of Saccharina japonica and Undaria pinnatifida. The plastid genomes of these three algal species retain a strong conservation of the GTG start codon while infrequently using TGA as a stop codon. In this regard, they differ substantially from the plastid genomes of Ectocarpus siliculosus and Fucus vesiculosus. Analysis of the nucleic acid substitution rates of the Laminariales plastid genes revealed that the petF gene has the highest substitution rate and the petN gene contains no substitution over its complete length. The variation in plastid genes between C. costata and S. japonica is lower than that between C. costata and U. pinnatifida as well as that between U. pinnatifida and S. japonica. Phylogenetic analyses demonstrated that C. costata and U. pinnatifida have a closer genetic relationship. We also identified two gene length mutations caused by the insertion or deletion of repeated sequences, which suggest a mechanism of gene length mutation that may be one of the key explanations for the genetic variation in plastid genomes.     

Genotyping of Human Brucella melitensis Biovar 3 Isolated from Shanxi Province in China by MLVA16 and HOOF

Background

Brucellosis presents a significant economic burden for China because it causes reproductive failure in host species and chronic health problems in humans. These problems can involve multiple organs. Brucellosis is highly endemic in Shanxi Province China. Molecular typing would be very useful to epidemiological surveillance. The purpose of this study was to assess the diversity of Brucella melitensis strains for epidemiological surveillance. Historical monitoring data suggest that Brucella melitensis biovar 3 is the predominant strain associated with the epidemic of brucellosis in Shanxi Province.

Methods/Principal Findings

Multiple-locus variable-number repeat analysis (MLVA-16) and hypervariable octameric oligonucleotide fingerprinting (HOOF-print) were used to type a human-hosted Brucella melitensis population (81 strains). Sixty-two MLVA genotypes (discriminatory index: 0.99) were detected, and they had a genetic similarity coefficient ranging from 84.9% to 100%. Eighty strains of the population belonged to the eastern Mediterranean group with panel 1 genotypes 42 (79 strains) and 43 (1 strain). A new panel 1 genotype was found in this study. It was named 114 MLVAorsay genotype and it showed similarity to the two isolates from Guangdong in a previous study. Brucella melitensis is distributed throughout Shanxi Province, and like samples from Inner Mongolia, the eastern Mediterranean genotype 42 was the main epidemic strain (97%). The HOOF-printing showed a higher diversity than MLVA-16 with a genetic similarity coefficient ranging from 56.8% to 100%.

Conclusions

According to the MLVA-16 and HOOF-printing results, both methods could be used for the epidemiological surveillance of brucellosis. A new genotype was found in both Shanxi and Guangdong Provinces. In areas with brucellosis, the MLVA-16 scheme is very important for tracing cases back to their origins during outbreak investigations. It may facilitate the expansion and eradication of the disease.     

Reproductive Isolation of Hybrid Populations Driven by Genetic Incompatibilities

Despite its role in homogenizing populations, hybridization has also been proposed as a means to generate new species. The conceptual basis for this idea is that hybridization can result in novel phenotypes through recombination between the parental genomes, allowing a hybrid population to occupy ecological niches unavailable to parental species. Here we present an alternative model of the evolution of reproductive isolation in hybrid populations that occurs as a simple consequence of selection against genetic incompatibilities. Unlike previous models of hybrid speciation, our model does not incorporate inbreeding, or assume that hybrids have an ecological or reproductive fitness advantage relative to parental populations. We show that reproductive isolation between hybrids and parental species can evolve frequently and rapidly under this model, even in the presence of substantial ongoing immigration from parental species and strong selection against hybrids. An interesting prediction of our model is that replicate hybrid populations formed from the same pair of parental species can evolve reproductive isolation from each other. This non-adaptive process can therefore generate patterns of species diversity and relatedness that resemble an adaptive radiation. Intriguingly, several known hybrid species exhibit patterns of reproductive isolation consistent with the predictions of our model.     

Regulation and Methylation of Tumor Suppressor MiR-124 by Androgen Receptor in Prostate Cancer Cells

Prostate cancer (PCa) is the most frequently diagnosed cancer for men in the developed world. Androgen receptor signaling pathway plays an important role in prostate cancer progression. Recent studies show that microRNA miR-124 exerts a tumor suppressive function in prostate cancer. However, the relationship between AR and miR-124 is unclear. In the present study, we found a negative feedback loop between AR and miR-124 expression. On one hand, miR-124 was a positively regulated target gene of the AR, on the other hand, overexpression of miR-124 inhibited the expression of AR. In addition, we found that miR-124-2 and miR-124-3 promoters were hypermethylated in AR-negative PCa cells. Furthermore, overexpression of miR-124 inhibited proliferation rates and invasiveness capacity of PCa cells in vitro, and suppressed xenograft tumor growth in vivo. Taken together, our results support a negative feedback loop between AR and miR-124 expression. Methylation of miR-124-2 and miR-124-3 may serve as a biomarker for AR-negative PCa cells, and overexpression of miR-124 might be of potential therapeutic value for the treatment of PCa.     

一株撕裂蜡孔菌的分离培养及其系统发育分析

目的:分离出一株撕裂蜡孔菌(Ceriporia lacerata),通过PDAY培养基培养后,进行了培养特性及系统发育分析.方法:PDAY培养基培养菌丝体,电镜扣描获得菌丝微观形态,利用分子生物学方法对其rRNA基因内转录间区(ITS区)进行了克隆测序,与Genbank中已有的有关序列进行比较.结果:其ITS区与撕裂蜡孔菌同源率为98.8%～100%,属于一单独分支中,与白囊耙齿菌(Irpex lacteus)、射脉菌(Phlebia albida)及齿白木层孔菌(Leucophellinus irpicoides)的同源率为83.7%、81.2%及83.5%.结论:形态结果及分子鉴定表明撕裂蜡孔菌(Ceriporia lacerata)培养成功,菌丝体的获得为进一步开发利用提供了依据.     

Sarcocystis cruzi: comparative studies confirm natural infections of buffaloes

Controversy exists concerning whether cattle and water buffalo sustain infections with cysts of distinct arrays of species in the genus Sarcocystis. In particular, morphologically similar parasites have been alternately ascribed to Sarcocystis cruzi or to Sarcocystis levinei, depending on their occurrence in cattle or water buffalo. We used light and transmission electron microscopy, genetic analysis, and experimental infections of definitive canine hosts to determine whether consistent differences could be identified from parasites derived from several natural infections of each host, examining several tissue types (esophagus, skeletal muscles, and heart). Cysts derived from cattle and water buffalo shared similar structure; variation among 18S rRNA sequences did not segregate consistently according to intermediate host type; parasites derived from cattle and water buffalo induced similar outcomes in the canine definitive host. One cattle specimen harbored unusually large (macroscopic) sarcocysts which nonetheless conformed to previously reported ultrastructural and genetic features of S. cruzi. Finding no consistent basis to differentiate between them, we conclude that the parasites infecting each host and tissue type correspond to S. cruzi. In our sample, no phylogenetically distinct taxon was sampled which might correspond to a distinct taxon previously described as S. levinei. Either that taxon was missed by our sampling effort, or it may represent a junior synonym to S. cruzi, which would then cycle between dogs and a broader range of intermediate bovine hosts than was previously considered.     

Presenilin-1 forms complexes with the cadherin/catenin cell-cell adhesion system and is recruited to intercellular and synaptic contacts

In MDCK cells, presenilin-1 (PS1) accumulates at intercellular contacts where it colocalizes with components of the cadherin-based adherens junctions. PS1 fragments form complexes with E-cadherin, beta-catenin, and alpha-catenin, all components of adherens junctions. In confluent MDCK cells, PS1 forms complexes with cell surface E-cadherin; disruption of Ca(2+)-dependent cell-cell contacts reduces surface PS1 and the levels of PS1-E-cadherin complexes. PS1 overexpression in human kidney cells enhances cell-cell adhesion. Together, these data show that PS1 incorporates into the cadherin/catenin adhesion system and regulates cell-cell adhesion. PS1 concentrates at intercellular contacts in epithelial tissue; in brain, it forms complexes with both E- and N-cadherin and concentrates at synaptic adhesions. That PS1 is a constituent of the cadherin/catenin complex makes that complex a potential target for PS1 FAD mutations.