Chain length distribution and aggregation of branched (1→3)-β-d-glucans from Saccharomyces cerevisae

Water-soluble (1→3)-β-d-glucans with 1,6-linked branches (SBG), originally isolated from the cell walls of Saccharomyces cerevisiae and partially depolymerised for optimal performance in wound healing applications, were studied by size exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS) detector and a viscosity detector at both high and ambient column temperatures. The strongly aggregating materials could be dispersed as single chains in water following partial carboxymethylation (degree of substitution (DS) 0.51 or higher). Lower DS (0.23) also dispersed as single chains provided a column temperature of 80°C was applied. Reduction of reducing ends prior to carboxymethylation was required to avoid alkaline peeling and hence to obtain correct molecular weight distributions of the native material. DS was determined using (13)C NMR and potentiometric titration (range 0.23-0.91). Further analysis of CM-SBG in the single chain state suggested a randomly coiled behaviour with marginal influence of the branches in terms of macromolecular dimensions, which were close to those of CM-curdlan. The result of the investigation is a simple and reliable protocol for preparing undegraded and un-aggregated SBG derivatives, which are well suited as a standard analysis of the molecular weight distribution of SBG-like molecules.     

中国琵甲族一新属二新种(鞘翅目：拟步甲科)

记述了鞘翅目拟步甲科琵甲族1新属2新种,即新琵甲属Neoblaps gen.nov.,会泽新琵甲N.huizensis sp.nov.;波密地琵甲Dila bomiana sp.nov.。列出了机关报属和新种与近缘属或种的视差鉴别特征或检索表,模式标本保存在河北大学博物馆。     

Histological,Physiological and Transcriptomic Analysis Reveal the Acute Alkalinity Stress of the Gill and Hepatopancreas of Litopenaeus vannamei

Marine Biotechnology - The pacific white shrimp (Litopenaeus vannamei) has gradually become a promising economic species in the development of saline-alkali water fishery. The study...     

Survival, synaptogenesis, and regeneration of adult mouse spiral ganglion neurons in vitro

The inner ear spiral ganglion is populated by bipolar neurons connecting the peripheral sensory receptors, the hair cells, with central neurons in auditory brain stem nuclei. Hearing impairment is often a consequence of hair cell death, e.g., from acoustic trauma. When deprived of their peripheral targets, the spiral ganglion neurons (SGNs) progressively degenerate. For effective clinical treatment using cochlear prostheses, it is essential to maintain the SGN population. To investigate their survival dependence, synaptogenesis, and regenerative capacity, adult mouse SGNs were separated from hair cells and studied in vitro in the presence of various neurotrophins and growth factors. Coadministration of fibroblast growth factor 2 (FGF-2) and glial cell line-derived neurotrophic factor (GDNF) provided support for long-term survival, while FGF-2 alone could strongly promote neurite regeneration. Fibroblast growth factor receptor FGFR-3-IIIc was found to upregulate and translocate to the nucleus in surviving SGNs. Surviving SGNs formed contacts with other SGNs after they were deprived of the signals from the hair cells. In coculture experiments, neurites extending from SGNs projected toward hair cells. Interestingly, adult mouse spiral ganglion cells could carry out both symmetric and asymmetric cell division and give rise to new neurons. The authors propose that a combination of FGF-2 and GDNF could be an efficient route for clinical intervention of secondary degeneration of SGNs. The authors also demonstrate that the adult mammalian inner ear retains progenitor cells, which could commit neurogenesis.     

miR-218 regulates focal adhesion kinase–dependent TGFβ signaling in fibroblasts

Scarring, which occurs in essentially all adult tissue, is characterized by the excessive production and remodeling of extracellular matrix by α-smooth muscle actin (SMA)–expressing myofibroblasts located within connective tissue. Excessive scarring can cause organ failure and death. Oral gingivae do not scar. Compared to dermal fibroblasts, gingival fibroblasts are less responsive to transforming growth factor β (TGFβ) due to the reduced expression, due to the reduced expression and activity of focal adhesion kinase (FAK) by this cell type. Here we show that, compared with dermal fibroblasts, gingival fibroblasts show reduced expression of miR-218. Introduction of pre–miR-218 into gingival fibroblasts elevates FAK expression and, via a FAK/src-dependent mechanism, results in the ability of TGFβ to induce α-SMA. The deubiquitinase cezanne is a direct target of miR-218 and has increased expression in gingival fibroblasts compared with dermal fibroblasts. Knockdown of cezanne in gingival fibroblasts increases FAK expression and causes TGFβ to induce α-smooth muscle actin (α-SMA). These results suggest that miR-218 regulates the ability of TGFβ to induce myofibroblast differentiation in fibroblasts via cezanne/FAK.     

Comparative Metabolomics Analysis between Red- and White-Flowered Common Buckwheat Cultivars

Common buckwheat (Fagopyrum esculentum), a specialty crop in southwest China, is not only used as a supplement to primary grain crops but also to produce beverages, such as tea and wine. To fully exploit the products made from common buckwheat flower, ultra-performance liquid chromatography–electrospray ionization– tandem mass spectrometry (UPLC–ESI–MS/MS) was conducted to analyze the metabolites in red- (‘Guihong 2’) and white-flowered (‘Fengtian 1’) buckwheat cultivars. A total of 784 metabolites were identified of which flavonoids were the largest group with 191 components, followed by organic acids and derivatives (126), and amino acids and derivatives (95). Besides, dozens of phenylpropanoids, nucleotides and derivates, lipids, alkaloids as well as several kinds of indole derivatives and sterides were detected. Among these rich varieties of metabolites, 24 metabolites were only detected in the red flower that mainly included 8 anthocyanins and 6 flavones, while 22 metabolites were only detected in the white flower, which mainly contained 5 lipids, 5 flavonoids, and 5 organic acids and derivatives. Our results enrich the metabolites’ information of buckwheat and may be helpful for the exploitation of products from common buckwheat flowers.     

斑马鱼tbx2b调控心脏房室间隔发育的功能研究*

tbx2是早期心脏发育的关键基因。为进一步探究其对房室间隔(AVC)发育的影响,研究利用CRISPR/Cas9介导的基因敲除技术,成功构建了斑马鱼tbx2b突变体。通过T7E1酶切对其F₀进行敲除效率检测,结果显示平均敲除效率约为57.5%。F₁进一步筛选获得tbx2b杂合突变体,测序结果显示突变类型为11 bp碱基缺失的移码突变。tbx2b杂合子内交获得纯合子,tbx2b纯合突变体在5 dpf死亡并出现早期心脏环化异常表型。斑马鱼整胚原位杂交实验显示在3 dpf tbx2b纯合突变体中, 心脏腔室分化特异性标志基因nppa、nppb表达上调并异位表达在AVC,而AVC发育关键基因has2的表达消失。高效构建tbx2b突变体并初探其对下游基因的影响,为后续深入研究tbx2b对心脏AVC发育的作用奠定了基础,同时加深了人们对早期心脏调控网络的认识。     

Improved gene targeting frequency in marine-derived filamentous fungus Aspergillus glaucus by disrupting ligD

Filamentous fungi from the marine environment have shown great potential as cell factories for the production of pharmacologically active metabolites, but extremely low frequency of homologous recombination brings difficulty to further molecular biology studies. To bypass this problem and develop a highly efficient gene targeting system in marine-derived filamentous fungus Aspergillus glaucus, LigD, a homolog of Neurospora crassa Mus-53 which is considered to play a significant role in nonhomologous end joining (NHEJ), was coloned and deleted, and frequency of targeted gene replacement (TGR) increased dramatically from <2% to 85% in comparison with that in the wild type, when containing 1000 bp of homologous flanking sequence. Such results strongly indicate that AgLigD is indeed involved in the repair of NHEJ in A. glaucus and functions in this pathway. Furthermore, the AgLigD-defective mutant has no discernible differences with wild type regarding sensitivity to mutagens and UV, growth characteristics and transformation frequency. The AgligD-deficient transformant, as the first NHEJ-defective mutant in the field of marine-derived filamentous fungus, will help in expediting studies of molecular biology of marine-derived microorganisms.