Transferability of microsatellite markers from Eucalyptus spp. to Eugenia dysenterica (Myrtaceae family)

Cagaita (Eugenia dysenterica) is a widespread plant found in the Brazilian cerrado. Its fruit is used for popular consumption and for industrial purposes. A battery of 346 primer pairs developed for Eucalyptus spp. was tested on cagaita. Only 10 primer pairs were found to be transferable between the two species. Using a polyacrilamide gel, an average of 10.4 alleles per locus was detected, in a sample of 116 individuals from 10 natural populations of cagaita. Seven polymorphic loci allowed estimation of genetic parameters, including expected average heterozigosity H_E = 0.442, diversity among populations, R_ST = 0.268 and gene flow Nm = 0.680.     

Mitogenomic phylogeny of the Percichthyidae and Centrarchiformes (Percomorphaceae): comparison with recent nuclear gene-based studies and simultaneous analysis

Delineation of the fish family Percichthyidae (Percomorphaceae) has a long and convoluted history, with recent morphological-based studies restricting species members to South American and Australian freshwater and catadromous temperate perches. Four recent nuclear gene-based phylogenetic studies, however, found that the Percichthyidae was not monophyletic and was nested within a newly discovered inter-familial clade of Percomorphaceae, the Centrarchiformes, which comprises the Centrarchidae and 12 other families. Here, we reexamined the systematics of the Percichthyidae and Centrarchiformes based on new mitogenomic information. Our mitogenomic results are globally congruent with the recent nuclear gene-based studies although the overall amount of phylogenetic signal of the mitogenome is lower. They do not support the monophyly of the Percichthyidae, because the catadromous genus Percalates is not exclusively related to the freshwater percichthyids. The Percichthyidae (minus Percalates) and Percalates belong to a larger clade, equivalent to the Centrarchiformes, but their respective sister groups are unresolved. Because all recent analyses recover a monophyletic Centrarchiformes but with substantially different intra-relationships, we performed a simultaneous analysis for a character set combining the mitogenome and 19 nuclear genes previously published, for 22 centrarchiform taxa. This analysis furthermore indicates that the Centrarchiformes are divided into three lineages and the superfamily Cirrhitoidea is monophyletic as well as the temperate and freshwater centrarchiform perch-like fishes. It also clarifies some of the relationships within the freshwater Percichthyidae.     

Molecular basis of bacterial resistance to chloramphenicol and florfenicol

Chloramphenicol (Cm) and its fluorinated derivative florfenicol (Ff) represent highly potent inhibitors of bacterial protein biosynthesis. As a consequence of the use of Cm in human and veterinary medicine, bacterial pathogens of various species and genera have developed and/or acquired Cm resistance. Ff is solely used in veterinary medicine and has been introduced into clinical use in the mid-1990s. Of the Cm resistance genes known to date, only a small number also mediates resistance to Ff. In this review, we present an overview of the different mechanisms responsible for resistance to Cm and Ff with particular focus on the two different types of chloramphenicol acetyltransferases (CATs), specific exporters and multidrug transporters. Phylogenetic trees of the different CAT proteins and exporter proteins were constructed on the basis of a multisequence alignment. Moreover, information is provided on the mobile genetic elements carrying Cm or Cm/Ff resistance genes to provide a basis for the understanding of the distribution and the spread of Cm resistance--even in the absence of a selective pressure imposed by the use of Cm or Ff.     

甲状腺乳头状癌组织微小RNA-93-5p、微小RNA-98-5p表达与临床病理特征和增殖、侵袭基因表达的关系研究

摘要 目的：研究甲状腺乳头状癌（PTC）组织微小核糖核酸-93-5p（miR-93-5p）、微小RNA-98-5p（miR-98-5p）表达与临床病理特征和增殖、侵袭基因表达的关系。方法：选取2020年10月到2023年10月在广东省中医院行手术切除的PTC患者153例作为研究对象,收集术中切除的癌组织以及癌旁组织。检测并比较癌组织与癌旁组织miR-93-5p、miR-98-5p及增殖基因、侵袭基因mRNA表达水平,分析miR-93-5p及miR-98-5p表达与PTC患者临床病理特征的关系。利用Pearson法分析miR-93-5p、miR-98-5p表达水平与增殖基因、侵袭基因mRNA表达的相关性。结果：癌组织的miR-93-5p表达水平较癌旁组织更高,miR-98-5p表达水平较癌旁组织更低（P<0.05）。miR-93-5p高表达PTC患者TNM分期Ⅲ~Ⅳ期、有淋巴结转移及低分化的比例较miR-93-5p低表达PTC患者更高（P<0.05）。miR-98-5p低表达PTC患者TNM分期Ⅲ~Ⅳ期、有淋巴结转移及低分化的比例较miR-98-5p高表达PTC患者更高（P<0.05）。癌组织的增殖基因程序性细胞死亡因子4（PDCD4）及蛋白磷酸酶4调节亚基 （PP4R1）水平较癌旁组织更低（P<0.05）,侵袭基因金属蛋白酶解离素9（ADAM9）及Bcl-6共抑制因子样蛋白（BCORL1）水平较癌旁组织更高（P<0.05）。Pearson法分析结果显示,miR-93-5p表达与增殖基因PDCD4及PP4R1表达水平呈负相关,与侵袭基因ADAM9及BCORL1表达水平呈正相关。miR-98-5p表达水平与增殖基因PDCD4及PP4R1水平呈正相关,与侵袭基因ADAM9及BCORL1表达水平呈负相关。结论：PTC患者癌组织miR-93-5p表达升高,miR-98-5p表达降低,与TNM分期、淋巴结转移及分化程度等临床病理特征有关,还可促进PTC癌细胞增殖、侵袭。     

Differential patterns of spatial divergence in microsatellite and allozyme alleles: further evidence for locus‐specific selection in the acorn barnacle,Semibalanus balanoides?

We compared patterns of genetic structure at potentially selected (two allozyme loci) and neutral molecular markers (six microsatellite loci) in the acorn barnacle, Semibalanus balanoides from the Gulf of St. Lawrence. Our results confirmed the presence of a geographical shift in alleles MPI and GPI near the Miramichi River. In contrast, no significant patterns of population differentiation among samples located north and south of the river mouth were detected for four of six microsatellite loci. However, analysis of molecular variance (amova) at individual loci revealed that a significant proportion of the total variance in allele frequencies was partitioned among samples located north and south of the river for both the allozyme and the other two microsatellite loci. The two most common alleles at these microsatellites showed frequencies that were highly correlated (r = 0.65-0.74, P < 0.05) with those of the MPI*2 allele, perhaps because of either physical linkage or epistasis. The two allozyme loci were significantly correlated in barnacles located north of the Miramichi River (r = 0.86, P < 0.05). Overall, our results supported the hypothesis that the broad scale pattern of allozyme allelic shifts is maintained by selection. They also indicated that microsatellites may not always behave in a neutral way and must be used cautiously, especially when evidence for genetic structuring relies on only a few assayed loci.     

Assessing differential gene expression with small sample sizes in oligonucleotide arrays using a mean-variance model

The identification of the genes that are differentially expressed in two-sample microarray experiments remains a difficult problem when the number of arrays is very small. We discuss the implications of using ordinary t-statistics and examine other commonly used variants. For oligonucleotide arrays with multiple probes per gene, we introduce a simple model relating the mean and variance of expression, possibly with gene-specific random effects. Parameter estimates from the model have natural shrinkage properties that guard against inappropriately small variance estimates, and the model is used to obtain a differential expression statistic. A limiting value to the positive false discovery rate (pFDR) for ordinary t-tests provides motivation for our use of the data structure to improve variance estimates. Our approach performs well compared to other proposed approaches in terms of the false discovery rate.     

白色獭兔蓝眼突变体的发现与遗传分析

文章设计了杂交、回交和全同胞交配3个实验, 对美系白色獭兔(♂)和青紫蓝肉兔(♀)杂交所产生的白色蓝眼獭兔突变体的遗传机制进行了等位性测试。结果表明, 白色獭兔蓝眼突变体是维也纳座位(V)发生隐性突变的结果。基因v纯合(vv)对家兔基本毛色基因座(A、B、C、D、E)具有隐性上位作用, 无论其他毛色座位的基因型如何, 只要vv存在即可产生白色蓝眼兔。vv基因型与rr基因型组合即可产生白色蓝眼獭兔。白色蓝眼獭兔突变体在我国家兔育种中是一个新发现, 其遗传机制的阐明, 对獭兔育种和生产具有重要的指导意义。     

九种蟋蟀mtDNA-16S rRNA基因序列及其系统进化(直翅目:蟋蟀科)

蟋蟀科5属9个种的线粒体16S rRNA基因部分序列被测定或从Gen Bank获得,比较其同源性,计算核苷酸使用频率,并构建NJ和MP分子系统树。在获得的449bp的序列中A、T、C和G碱基含量分别为31．8％、36．9％、9．9％和21．4％,A T平均含量为68．7％。研究结果表明：所研究的5属9种蟋蟀聚成3个聚类簇,斗蟋属先与灶蟋属汇合,再与棺头蟋属构成聚类簇Ⅰ;油葫芦属黑脸油葫芦和北京油葫芦与蟋蟀属的家蟋相聚构成聚类簇Ⅱ;蟋蟀属的田蟋单独构成聚类簇Ⅲ。