Genetic analysis of a novel plasmid pZMX101 from Halorubrum saccharovorum: determination of the minimal replicon and comparison with the related haloarchaeal plasmid pSCM201

The DNA sequence of a novel haloarchaeal plasmid pZMX101 (3918 bp) from Halorubrum saccharovorum was determined and six ORFs were predicted. The largest ORF encodes a putative replication initiation protein RepA, which shares 40% sequence similarity with the Rep201 of a theta-replication plasmid pSCM201 recently isolated from Haloarcula, suggesting that pZMX101 might replicate via a theta-type mechanism. Using pZMX101 as the only haloarchaeal replicon, a shuttle vector pZMX108 was constructed and successfully transformed into Haloferax volcanii DS70. Based on this in vivo system, the minimal replicon (1978 bp) of pZMX101 was determined. It is composed of the repA gene plus c. 400-bp upstream and 300-bp downstream sequences. Significantly, the putative replication origin of pZMX101 and that of pSCM201 contain different types of sequence motifs, and these two plasmids exhibit distinct host preference for Haloferax and Haloarcula, respectively.     

个性化后侧入路治疗胫骨平台后髁冠状面骨折

目的:探讨个性化后侧入路治疗单纯性胫骨平台后髁冠状面骨折手术方法。方法:12例单纯性胫骨平台后髁冠状面骨折的患者,采用后内侧或后外侧以及后内后外联合入路切开复位内固定治疗。结果:12例均获随访,随访时间8-24个月,平均13个月。患者膝关节功能评定按Hohl评分标准:优10例,良2例。复查X线片:骨折复位良好,关节面未见明显塌陷。结论:个性化后侧入路治疗单纯性胫骨平台后髁骨折冠状面可直视下暴露胫骨平台后髁,提供了更广阔的操作空间,有利于骨折的解剖复位内固定。     

Recombinatorial Biases and Convergent Recombination Determine Interindividual TCRβ Sharing in Murine Thymocytes

Overlap of TCR repertoires among individuals provides the molecular basis for public T cell responses. By deep-sequencing the TCRβ repertoires of CD4(+)CD8(+) thymocytes from three individual mice, we observed that a substantial degree of TCRβ overlap, comprising ～10-15% of all unique amino acid sequences and ～5-10% of all unique nucleotide sequences across any two individuals, is already present at this early stage of T cell development. The majority of TCRβ sharing between individual thymocyte repertoires could be attributed to the process of convergent recombination, with additional contributions likely arising from recombinatorial biases; the role of selection during intrathymic development was negligible. These results indicate that the process of TCR gene recombination is the major determinant of clonotype sharing between individuals.     

Genomic Shifts,Phenotypic Clines,and Fitness Costs Associated With Cold Tolerance in the Asian Tiger Mosquito

Climatic variation is a key driver of genetic differentiation and phenotypic traits evolution, and local adaptation to temperature is expected in widespread species. We investigated phenotypic and genomic changes in the native range of the Asian tiger mosquito, Aedes albopictus. We first refine the phylogeographic structure based on genome-wide regions (1,901 double-digest restriction-site associated DNA single nucleotide polymophisms [ddRAD SNPs]) from 41 populations. We then explore the patterns of cold adaptation using phenotypic traits measured in common garden (wing size and cold tolerance) and genotype–temperature associations at targeted candidate regions (51,706 exon-capture SNPs) from nine populations. We confirm the existence of three evolutionary lineages including clades A (Malaysia, Thailand, Cambodia, and Laos), B (China and Okinawa), and C (South Korea and Japan). We identified temperature-associated differentiation in 15 out of 221 candidate regions but none in ddRAD regions, supporting the role of directional selection in detected genes. These include genes involved in lipid metabolism and a circadian clock gene. Most outlier SNPs are differently fixed between clades A and C, whereas clade B has an intermediate pattern. Females are larger at higher latitude yet produce no more eggs, which might favor the storage of energetic reserves in colder climate. Nondiapausing eggs from temperate populations survive better to cold exposure than those from tropical populations, suggesting they are protected from freezing damages but this cold tolerance has a fitness cost in terms of egg viability. Altogether, our results provide strong evidence for the thermal adaptation of A. albopictus across its wide temperature range.     

Current status and future prospects of Zoige Marsh in Eastern Qinghai-Tibet Plateau

Zoige Marsh, located in the Northeastern Qianghai-Tibet Plateau, is the largest highland marsh in the world. The marsh is one of the hotspots for biodiversity, harboring many endemic and endangered species, including Grus nigricollis, the only plateau crane. Zoige Marsh has a large area of high-quality grasslands, serving as the fifth largest livestock base in China, and it is also the major water source to the headstream of the Yellow River. However, due to global warming and unwise use of the marsh resources, including ditching for grassland enlargement, peat exploitation, and livestock grazing, since the 1970s, Zoige Marsh has suffered severe ecosystem degradations such as vegetation recessive succession, biodiversity loss, soil deterioration, and rodent disasters. It is therefore imperative to restore the damaged marsh. We propose in this paper that ecological engineering and livestock population control must be taken as measures for ecological restoration and biodiversity protection.     

Critical Roles of Voltage-Dependent Sodium Channels in the Process of Synaptogenesis During the Postnatal Cortical Development of Rats

The developmental changes of the sodium channel and construction of synapse connection were studied in cerebral cortical pyramidal neurons of rats at different age groups. We used whole-cell patch-clamp recordings to characterize electrophysiological properties of cortical neurons at different age stages, including the sodium currents, APs evoked by depolarizing current and short-term plasticity of the eEPSCs. The result shows that the sodium currents undergo a hyperpolarizing shift in activation process and acceleration of activation and inactivation with age. The maximal sodium current also increased with maturation, and the evident difference appeared from P7–P11 (with the day of birth as P0) to P12–P15 group. The tendency of the sodium current density changes which exhibited the same properties as that of sodium current, showed the significant increases from P19–P21 to P ≥ 22 group. The APs’ parameters exhibited the age-dependent changes except the threshold, including the increase of the peak amplitude from P ≤ 6 to P16–P18 groups, and the curtailment of duration and the time-to-peak with age. The amplitude of 1st eEPSC increased with maturation, and STP displays depression at all observed groups. In addition, although STP also exhibited depression in response to last three stimulations in P ≥ 22 group, the 2nd response showed the tendency of facilitation compared with the younger age groups. Our results indicated that the cerebral cortical pyramidal neurons of rats are undergoing marked changes in the characteristics of their sodium channels with maturation, which play a critical role in synaptogenesis and construction of the neuronal network.     

The expression and function of β-1,4-galactosyltransferase-I in dendritic cells

β-1,4-Galactosyltransferase-I (GalTI) is unusual among the galactosyltransferase family, which has two isoforms that differ only in the length of their cytoplasmic domains [1]. In this study, we found that both the long and short isoforms of GalTI were expressed in human monocyte-derived dendritic cells (MoDCs), and localized in the cytoplasm near nucleus and cytomembrane. The expression level of GalTI and cellular adhesion ability was increased when DCs continued to mature. We also demonstrated that the cellular adhesion ability of DCs was inhibited by α-lactalbumin (α-LA) via interference with cell surface GalTI function, suggesting that the adhesion ability was positively correlated with the expression of cell surface long GalTI. α-LA also could inhibit DC-T clustering and CD4⁺ T cell proliferation. Collectively, the data suggests that GalTI might act as a key adhesion molecular participating in T cells-DCs contacts.     

A method for the identification of glycoproteins from human serum by a combination of lectin affinity chromatography along with anion exchange and Cu-IMAC selection of tryptic peptides

This paper reports a method for identifying glycoproteins from human serum. Glycoproteins were selected with a concanavalin A (Con A) lectin column and then tryptically digested prior to sequential chromatographic selection of acidic and histidine containing peptides. Acidic peptides were selected with a strong anion exchange (SAX) column. Peptides captured by the SAX columns were then released and histidine-containing peptides in the mixture selected with a copper loaded immobilized metal affinity chromatography (Cu-IMAC) column. This serial chromatographic selection process reduced the complexity of proteolytic digests by more than an order of magnitude. Peptides selected by this serial process were then fractionated by reversed-phase chromatography (RPC) and identified by tandem mass spectrometry. The method was initially validated using human transferrin before application to human serum. The results show that all the peptides identified except one contained histidine and acidic amino acids.