RNA polymerases can be shared by a particular group of genes in a transcription "factory" in nuclei, where transcription may be coordinated in concert with the distribution of coexpressed genes in higher-eukaryote genomes. Moreover, gene expression can be modulated by regulatory elements working over a long distance. Here, we compared the conformation of a 130-kb chromatin region containing the mouse ␣-globin cluster and their flanking housekeeping genes in 14.5-day-postcoitum fetal liver and brain cells. The analysis of chromatin conformation showed that the active ␣1 and ␣2 globin genes and upstream regulatory elements are in close spatial proximity, indicating that looping may function in the transcriptional regulation of the mouse ␣-globin cluster. In fetal liver cells, the active ␣1 and ␣2 genes, but not the inactive gene, colocalize with neighboring housekeeping genes C16orf33, C16orf8, MPG, and C16orf35. This is in sharp contrast with the mouse ␣-globin genes in nonexpressing cells, which are separated from the congregated housekeeping genes. A comparison of RNA polymerase II (Pol II) occupancies showed that active ␣1 and ␣2 gene promoters have a much higher RNA Pol II enrichment in liver than in brain. The RNA Pol II occupancy at the gene promoter, which is specifically repressed during development, is much lower than that at the ␣1 and ␣2 promoters. Thus, the mouse ␣-globin gene cluster may be regulated through moving in or out active globin gene promoters and regulatory elements of a preexisting transcription factory in the nucleus, which is maintained by the flanking clustered housekeeping genes, to activate or inactivate ␣-globin gene expression.The human genome project has revealed that there are about 32,000 protein-encoding genes, which are distributed in 22 pairs of autosomes and 2 sex chromosomes. The genomewide bioinformatic analysis of chromosomal gene expression profiles and chromosomal gene positions reveals that genes are not randomly distributed in the genome. Moreover, highly expressed genes, especially housekeeping genes, are often clustered within specific chromosomal regions (9, 25), suggesting that their chromosomal locations may be related to their transcriptional activities and inherent regulatory properties (42,44). The estimation of the total number of nascent transcripts, active polymerase molecules, and number of transcription sites within a cell suggests that many different templates may be attached in a "cloud" of loops around a site; each site, or transcription "factory," would contain approximately 30 active polymerases and associated transcripts (22). Active RNA polymerases are concentrated in these discrete "factories," where they work together on the transcription of particular groups of genes (34,35,39). However, little is known about the functional correlation between the clustered gene order and their transcription. It is also unclear how these clustered genes are spatially organized in nuclei with respect to transcription and how they, as individual transcription unit...

A Gram-negative, non-motile, rod-shaped and pink-pigmented bacterium, designated strain X2-1g T , was isolated from a mixture of sand samples collected from the desert of Xinjiang, China, after exposure of the sand to 8 kGy gamma radiation. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that this isolate represents a novel member of the genus Hymenobacter, with low sequence similarities (,97 %) to recognized Hymenobacter species. Biolog GN2 assays supported this conclusion. Optimum growth was observed at pH 7 and 28 6C. The strain contained MK-7 as the predominant menaquinone and the major fatty acids were iso-C 15 : 0 (19.5 %), C 16 : 1 v7c/iso-C 15 : 0 2-OH (20.2 %), C 16 : 1 v5c (10.6 %), C 16 : 0 (6.2 %), anteiso-C 17 : 1 B/iso-C 17 : 1 I (8.5 %) and C 18 : 0 (6.5 %). The DNA G+C content was 54 mol% (T m ). On the basis of the polyphasic evidence presented, it is proposed that strain X2-1g T represents a novel species of the genus Hymenobacter, for which the name Hymenobacter xinjiangensis sp. nov. is proposed. The type strain is X2-1g T (5CCTCC AB 206080 T 5IAM 15452 T ).

No abstract

Attention-deficit hyperactivity disorder (ADHD) seriously affects children’s health, and the gut microbiome has been widely hypothesized to play a role in the regulation of ADHD behavior. The present study aims to the biosynthesize of zinc oxide nanoparticles (ZnONPs) by using Acinetobacter johnsonii strain RTN1, followed by their characterization through state-of-the-art material characterization techniques, viz., UV–vis spectroscopy, Fourier transform infrared spectroscopy, and transmission and scanning electron microscopic analyses with energy dispersive spectrometry. Moreover, we investigated and compared the population composition of gut microbiota and their susceptibility to biogenic ZnONPs between healthy and ADHD children based on the traditional plate method and 16S rRNA amplicon sequence analysis. The antibacterial effect of ZnONPs against gut bacteria was also determined by measurement of live cell number, living/dead bacterial staining test, and flow cytometry observation. The present study revealed that the number of live gut bacteria in healthy children was more than 10-fold higher than that in ADHD children; however, the community structure of gut bacteria has changed, while greater diversity was found in gut bacteria from ADHD children. In addition, we found that the number of live gut bacteria in healthy and ADHD children was reduced by ZnONPs, which shows an increased and reduced effect in composition of gut bacteria from healthy and ADHD children, respectively. It was also noted that the main mechanism of ZnONPs may be to inhibit the growth of gut bacteria rather than to kill them, while the nanoparticle-resistant strains in healthy children is also different from that in ADHD children. Some representative bacteria, in particular nanoparticle-resistant bacteria, were successfully isolated and identified. Overall, this study revealed the potential correlation of ADHD with gut bacteria and provided a new possibility to prevent ADHD by the combination of nanoparticle and its resistant bacteria.

No abstract