Chitooligosaccharide (COS) has been recognized to exhibit efficient anti-oxidant activity. Enzymatic hydrolysis using chitosanases can retain all the amino and hydroxyl groups of chitosan, which are necessary for its activity. In this study, a new chitosanase encoding gene, csnQ, was cloned from the marine Bacillus sp. Q1098 and expressed in Escherichia coli. The recombinant chitosanase, CsnQ, showed maximal activity at pH 5.31 and 60 °C. Determination of CsnQ pH-stability showed that CsnQ could retain more than 50% of its activity over a wide pH, from 3.60 to 9.80. CsnQ is an endo-type chitosanase, yielding chitodisaccharide as the main product. Additionally, in vitro and in vivo analyses indicated that chitodisaccharide possesses much more effective anti-oxidant activity than glucosamine and low molecular weight chitosan (LMW-CS) (~5 kDa). Notably, to our knowledge, this is the first evidence that chitodisaccharide is the minimal COS fragment required for free radical scavenging.

Pantothenate kinase (PanK) catalyzes the first step of the universal five-step coenzyme A (CoA) biosynthetic pathway. The recently characterized type III PanK (PanK-III, encoded by the coaX gene) is distinct in sequence, structure and enzymatic properties from both the long-known bacterial type I PanK (PanK-I, exemplified by the Escherichia coli CoaA protein) and the predominantly eukaryotic type II PanK (PanK-II). PanK-III enzymes have an unusually high Km for ATP, are resistant to feedback inhibition by CoA, and are unable to utilize the N-alkylpantothenamide family of pantothenate analogues as alternative substrates, thus making type III PanK ineffective in generating CoA analogues as antimetabolites in vivo. Previously, we reported the crystal structure of the PanK-III from Thermotoga maritima and identified it as a member of the "acetate and sugar kinase/heat shock protein 70/actin" (ASKHA) superfamily. Here we report the crystal structures of the same PanK-III in complex with one of its substrates (pantothenate), its product (phosphopantothenate) as well as a ternary complex structure of PanK-III with pantothenate and ADP. These results are combined with isothermal titration calorimetry experiments to present a detailed structural and thermodynamic characterization of the interactions between PanK-III and its substrates ATP and pantothenate. Comparison of substrate binding and catalytic sites of PanK-III with that of eukaryotic PanK-II revealed drastic differences in the binding modes for both ATP and pantothenate substrates, and suggests that these differences may be exploited in the development of new inhibitors specifically targeting PanK-III.

ABSTACTTo understand the prevalence and evolution of drug resistant HIV strains in Henan China after the implementation of free antiretroviral therapy for AIDS patients. 45 drug naïve AIDS patients, 118 AIDS patients who received three months antiretroviral therapy and 124 AIDS patients who received six months antiretroviral treatment were recruited in the southern part of Henan province. Information on general condition, antiretroviral medicines, adherence and clinical syndromes were collected by face to face interview. Meanwhile, 14ml EDTA anticoagulant blood was drawn. CD4/CD8 T cell count, viral load and genotypic drug resistance were tested. The rates of clinical improvement were 55.1% and 50.8% respectively three months and six months after antiretroviral therapy. The mean CD4 cell count after antiretroviral therapy was significantly higher than in drug naïve patients. The prevalence rate of drug resistant HIV strains were 13. 9%, 45.4% and 62.7% in drug naïve patients, three month treatment patients and six month treatment patients, respectively. The number of resistance mutation codons and the frequency of mutations increased significantly with continued antiretroviral therapy. The mutation sites were primarily at the 103, 106 and 215 codons in the three-month treatment group and they increased to 15 codon mutations in the six-month treatment group. From this result, the evolution of drug resistant strains was inferred to begin with the high level NNRTI resistant strain, and then develop low level resistant strains to NRTIs. The HIV strains with high level resistance to NVP and low level resistance to AZT and DDI were highly prevalent because of the AZT+DDI+NVP combination therapy. These HIV strains were also cross resistant to DLV, EFV, DDC and D4T. Poor adherence to therapy was believed to be the main reason for the emergence and prevalence of drug resistant HIV strains. The prevalence of drug resistant HIV strains was increased with the continuation of antiretroviral therapy in the southern part of Henan province. Measures, that could promote high level adherence, provide new drugs and change ART regimens in failing patients, should be implemented as soon as possible.

Objective: This study focused on the efficacy and safety of thalidomide for patients with thalassemia intermedia (TI) in a multicenter trial. Methods：Clinical and laboratory data of 62 patients subjected to thalidomide therapy in four centers were retrospectively analyzed. We evaluated the efficacy and safety of thalidomide in the short-term (three months) and long-term follow-up (12 and 24 months). Response to thalidomide was defined as follows: Main Responder (MaR) showing an increase in Hb level of >2.0 g/dl or removal from blood transfusion and Minor Responder (MiR) achieving elevated hemoglobin (Hb) level of 1.0-2.0 g/dl or ≥50% reduction in blood transfusion frequency. Results：The overall response rate (ORR) of 62 patients with TI was 93.5% (58/62), with MaR and MiR rates accounting for 62.9% (39/62) and 30.6% (19/62) in short-term follow-up and 66.1% (41/62) and 27.4% (17/62) in long-term follow-up, respectively. The clinical response during long-term follow-up was maintained and the Hb level remained stable during the observation period. The response was still observed in patients with dose reduction despite a slight decrease in Hb level. However, Hb decreased rapidly to the baseline level after drug discontinuation. No effect of thalidomide on spleen size in nonsplenectomized patients was evident. Minimal side-effects were documented throughout, except peripheral neurotoxicity in one patient. Nevertheless, the mean serum ferritin (SF) level was significantly increased after treatment. Conclusion: Thalidomide had significant therapeutic effects on patients with TI, and the response was sustained with acceptable short-term and long-term adverse reactions. While these preliminary results support the potential long-term efficacy and safety of thalidomide as a therapeutic agent for TI, several issues need to be addressed before its application in the clinic.

S100B protein is a calcium-binding protein mostly derived from glial cells, which exerts trophic or toxic effects on neural cell depending on its concentration. It has been reported that S100B played an important role as a potential marker in psychiatric disorders. Thus, we will explore the clinical implication of S100B in major depression, especially the effect of gender and numbers of depressive episodes on S100B. The levels of serum S100B were measured with enzyme-linked immunosorbent assay (ELISA) in 54 patients with major depression and 35 age-matched healthy controls. The S100B levels in major depressed patients were significantly higher than those in controls. The serum S100B levels in female patients were significantly higher than those in male patients. Patients with recurrent depressive episodes had significantly higher S100B levels than those in first-episode depression. Serum S100B levels were significantly positive related with the numbers of depressive episode, family history and cognitive disturbance scores. These findings confirmed an increase in serum S100B levels in major depressive patients and presence of a sexual dimorphism. Moreover, numbers of depressive episodes in depression seemed to have an additional increasing effect on S100B levels.

Our findings did not suggest association of S100B gene polymorphisms in patients with MDD in China. We found there were differences in depressive episodes among different genotypes of S100B gene.

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