Biochemical Activity of PIF1 Helicase from Thermophilic Bacteria / 中国生物化学与分子生物学报

Petite integration frequency 1 (PIF1) helicases are ubiquitous enzymes which play vital roles in nearly all DNA metabolic processes. In recent years, the biochemical activity and three-dimensional structure of several PIF1 helicases have been reported, but there are few reports on the PIF1 helicase of bacteria living in extreme environments. In this paper, a series of biochemical and biophysical techniques were used to study the Thermodesulfovibrio yellowstonii PIF1 (Ty.PIF1) helicase in many aspects. Ty. PIF1 was obtained with a purity of over 90% and good uniformity using the prokaryotic expression and purification system. Ty.PIF1 is a monomer with a calculated molecular weight of 60 kD in solution. Ty. PIF1 has high thermal stability. The secondary structure remains stable when the temperature is below 65 ℃, and the secondary structure changes only when the temperature is above 70 ℃. The optimal unwinding temperature of Ty.PIF1 in vitro is 45 ℃, which is not the optimal temperature for the survival of thermodesulfovibrio yellowstonii. It indicates that when Ty.PIF1 exerts its enzymatic activity in vivo, it may require the participation of other cofactors. Ty.PIF1 can exert unwinding activity in a wide temperature range (20-55 ℃), and the presence of enzyme activity at 55 ℃ indicates that Ty.PIF1 has heat-resistant properties. Ty.PIF1 prefers to bind to substrates containing ssDNA, but there is certain requirement for the length of the ssDNA, which is at least 4 nt in length. Ty.PIF1 can also bind to the G

Bacterial degradation of anthraquinone dyes / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Anthraquinone dyes, which contain anthraquinone chromophore groups, are the second largest class of dyes after azo dyes and are used extensively in textile industries. The majority of these dyes are resistant to degradation because of their complex and stable structures; consequently, a large number of anthraquinone dyes find their way into the environment causing serious pollution. At present, the microbiological approach to treating printing and dyeing wastewater is considered to be an economical and feasible method, and reports regarding the bacterial degradation of anthraquinone dyes are increasing. This paper reviews the classification and structures of anthraquinone dyes, summarizes the types of degradative bacteria, and explores the possible mechanisms and influencing factors of bacterial anthraquinone dye degradation. Present research progress and existing problems are further discussed. Finally, future research directions and key points are presented.

Bacterial degradation of anthraquinone dyes / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Anthraquinone dyes, which contain anthraquinone chromophore groups, are the second largest class of dyes after azo dyes and are used extensively in textile industries. The majority of these dyes are resistant to degradation because of their complex and stable structures; consequently, a large number of anthraquinone dyes find their way into the environment causing serious pollution. At present, the microbiological approach to treating printing and dyeing wastewater is considered to be an economical and feasible method, and reports regarding the bacterial degradation of anthraquinone dyes are increasing. This paper reviews the classification and structures of anthraquinone dyes, summarizes the types of degradative bacteria, and explores the possible mechanisms and influencing factors of bacterial anthraquinone dye degradation. Present research progress and existing problems are further discussed. Finally, future research directions and key points are presented.

Differential Innervation of Secretory Coils and Ducts in Human Eccrine Sweat Glands / 中华医学杂志(英文版)

Background@#Previous studies demonstrate that eccrine sweat glands are innervated by both cholinergic and adrenergic nerves. However, it is still unknown whether the secretory coils and ducts of eccrine sweat glands are equally innervated by the sympathetic nerve fibers. To well understand the mechanisms on sweat secretion and reabsorption, the differential innervation of secretory coils and ducts in human eccrine sweat glands was investigated in the study.@*Methods@#From June 2016 to June 2017, six human skins were fixed, paraffin-embedded, and cut into 5 μm-thick sections, followed by costaining for nerve fiber markers protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH) and vasoactive intestinal peptide (VIP), and eccrine sweat gland markers K7, S100P, and K14 by combining standard immunofluorescence with tyramide signal amplification (IF-TSA). Stained sections were observed under the microscope, photographed, and analyzed.@*Results@#The fluorescent signals of PGP 9.5, TH, and VIP were easily visualized, by IF-TSA, as circular patterns surrounding eccrine sweat glands, but only PGP 9.5 could be observed by standard IF. The IF-TSA method is more sensitivity than standard IF in detecting antigens expressed at low levels. PGP 9.5, TH, and VIP appeared primarily surrounding the secretory coils and sparsely surrounding the sweat ducts.@*Conclusion@#Sweat secretion is mainly controlled by autonomic nerves whereas sweat reabsorption is less affected by nerve activity.

Signal transduction by protein tyrosine kinases and antitumor agents / 药学学报

Intracellular signal transduction plays an important role in the process of cellular metabolism, segmentation, differentiation, biological behaviour and cell death. Overactive signal transduction relates to tumor development and progression. Signaling pathways operated by protein tyrosine kinases (PTKs) will be illuminated here briefly. The Ras/Raf/MAPK and PI-3K/Akt pathways through receptor protein tyrosine kinases (RTKs), the Src, Bcr-Abl and JAK/STAT pathways by non-receptor protein tyrosine kinases (nrPTKs) are shown separately. Antitumor agents targeting the key proteins involved in the above five signalling routes are also summarized in this review.

Identification and cell phenotype transdifferentiation of adipose-derived stem cells / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the transdifferentiation of the ADSCs to epidermal cells.</p><p><b>METHODS</b>ADSCs were isolated and cultured from rat adipose tissue by digestion of enzyme. ADSCs was identified by immunocytochemistry and flow cytometry. ADSCs were divided into four groups in order to induce: the condition medium (containing 30% superior of homogenizing rat skin in 10% FBS/DMEM) group, 7 days; 10% FBS/DMEM with EGF (20 ng/ml) group, 7 days; the condition medium for 4 days and then 10% FBS/DEME instead of the condition medium for 3 days group; 10% FBS/DMEM for 7 days group (control group). Cytokeratin 19 and cytokeratin 10 expressions in ADSCs were detected by flow cytometry.</p><p><b>RESULTS</b>(1) The results of immunocytochemistry showed that ADSCs were positive for CD49d and negative for CD106, CD34, CD19, CD10. The results of flow cytometry showed ADSCs were positive for CD49d and CD44. (2) The CK19 expression of ADSCs was 45.32% in the condition medium group, 26.58% in the condition medium with EGF group, 23.37% in te condition medium for 4 days and then 10% FBS/DMEM instead of the condition medium for 3 days gropu and 18.53% in control group, P <0.01. The CK10 expression of ADSCs was 43.56% in the condition medium group, 25.54% in the condition medium with EGF group, 18.20% in the condition medium for 4 days and then 10% FBS/DMEM instead of the condition medium for 3 days group and 2.46% in control group, P < 0.01.</p><p><b>CONCLUSIONS</b>The superior of homogenizing rat skin can induce CK19 and CK10 expressing in ADSCs, and thereby demonstrating ADSCs can differentiate to epidermal cell phenotype in vitro.</p>