The morphological and molecular analyses of a new South American urban tardigrade offer new insights on the biological meaning of the Macrobiotus hufelandi group of species (Tardigrada: Macrobiotidae)

Worldwide knowledge of tardigrade fauna is still limited, and many areas such as South America are not well studied. The collection of new substrates in Argentinean urban areas provided an opportunity to describe the new tardigrade species Macrobiotus kristenseni sp. nov. This species has been studied with an integrative taxonomic approach, analysing its morphology by light and scanning electron microscopy, and considering two genes (cox1 and 18S rRNA) for DNA barcoding and phylogenetic purposes. The species belongs to the Macrobiotus hufelandi group of species, and it is characterized by egg processes in the shape of elongated cones with truncated and enlarged apexes, and by a high genetic distance with respect to closely related species (cox1: 18.2–33.4%). Morphological and molecular data show that the Macrobiotus hufelandi group of species has to be considered a true biological entity; one of the more widespread tardigrade lineages in continental environments. http://www.zoobank.org/urn:lsid:zoobank.org:pub:2CA51ABA-5570-4AFB-8182-CE499D97B0F1     

Nine new species of the subgenus Stegana (Oxyphortica) from the Oriental region,with morphological and molecular evidence based on Chinese species (Diptera: Drosophilidae)

Nine new species of the subgenus Stegana (Oxyphortica) have been discovered from the Oriental Region: S. (O.) chuanjiangi Zhang and Chen, sp. nov., S (O.) dainuo Wang and Chen, sp. nov., S. (O.) dawa Zhang and Chen, sp. nov., S. (O.) laohlie Zhang and Chen, sp. nov., S. (O.) luchun Wang and Chen, sp. nov., S. (O.) mengwan Wang and Chen, sp. nov., S. (O.) triodonta Cheng and Chen, sp. nov. from southern China; S. (O.) dehiscens Cheng and Chen, sp. nov. and S. (O.) spinosa Cheng and Chen, sp. nov. from eastern Malaysia. One newly recorded species from China: S. (O.) maichouensis Sidorenko is re-described. The DNA sequences of the mitochondrial COI gene with BOLD Process ID and GenBank accession numbers are provided for the above seven new species and five known species from China: S. (O.) acutipenis Xu, Gao and Chen, S. (O.) adentata Toda and Peng, S. (O.) hirtipenis Xu, Gao and Chen, S. (O.) latipenis Xu, Gao and Chen, and S. (O.) maichouensis Sidorenko. Intra- and interspecific pairwise K-2P distances among these species are summarized and the phylogenetic relationships are reconstructed based on the neighbour-joining (NJ) analyses.

www.zoobank.org/urn:lsid:zoobank.org:pub:2FA403F6-5535-40A4-9FD0-ADB9913EDE83.     

Histone methylation and ubiquitination with their cross-talk and roles in gene expression and stability

Methylation of lysine residues of histones is associated with functionally distinct regions of chromatin, and, therefore, is an important epigenetic mark. Over the past few years, several enzymes that catalyze this covalent modification on different lysine residues of histones have been discovered. Intriguingly, histone lysine methylation has also been shown to be cross-regulated by histone ubiquitination or the enzymes that catalyze this modification. These covalent modifications and their cross-talks play important roles in regulation of gene expression, heterochromatin formation, genome stability, and cancer. Thus, there has been a very rapid progress within past several years towards elucidating the molecular basis of histone lysine methylation and ubiquitination, and their aberrations in human diseases. Here, we discuss these covalent modifications with their cross-regulation and roles in controlling gene expression and stability. Received 24 September 2008; received after revision 21 November 2008; accepted 28 November 2008     

DNA methylation of fly genes and transposons

The use of anti-5-methylcytosine antibodies in affinity columns allowed the identification of methylated sequences in the genome of Drosophila melanogaster adults. In view of the presence of transposable elements amongst the identified sequences, it has been suggested that DNA methylation is involved in transposon control in the fly genome. On the contrary, a reanalysis of these data furnishes several intriguing elements that could raise new questions about the role that DNA methylation plays in the fly genome. The aim of the present paper is to discuss some features that emerge from the analysis of the identified methylated sequences. Received 26 January 2006; received after revision 8 May 2006; accepted 2 June 2006     

从线粒体DNA控制区基因探讨红腹锦鸡和白腹锦鸡的分类关系

用聚合链式反应(PCR)和直接测序的方法测定红腹锦鸡(Chrysolophus pictus)和白腹锦鸡(C.amherstiae)各5个样本线粒体DNA控制区的468 bp的序列,共发现26个变异位点.红腹锦鸡的序列变异率为0.90%,白腹锦鸡的序列变异率是0.17%,两者差异极显著.红腹锦鸡和白腹锦鸡的3种碱基(A,T,C)含量差异显著.根据Kumar双参数法计算两种锦鸡的遗传距离为0.035±0.008,按线粒体DNA控制区的进化速率2%/Myr计算,它们的分歧进化的时间大约是(1.75±0.40)Myr,结果支持它们是两个独立的种.红腹锦鸡和白腹锦鸡可能分别起源于秦岭以南地区和横断山脉.     

He—Ne激光对鲱鱼DNA X射线衍射谱的影响

用He-Ne激光处理鲱鱼DNA，测试处理前后鲱鱼DNA的X射线衍射谱。结果显示处理前后鲱鱼DNA的X射线衍射谱发生了明显变化。为激光生物学效应的机理解释提供了实验依据。     

Ancient DNA sequences of rice from the low Yangtze reveal significant genotypic divergence

Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.