Biodegradation pathway and detoxification of the diazo dye Reactive Black 5 by Phanerochaete chrysosporium

The in vivo biodegradation of the diazo dye Reactive Black 5 (RB5) by Phanerochaete chrysosporium immobilised on cubes of nylon sponge and on sunflower-seed shells (SS) in laboratory-scale bioreactors was investigated. The SS cultivation led to the best results with a decolouration percentage of 90.3% in 72 h for an initial RB5 concentration of 100 mg/L. It was found that the addition of 0.4 mM veratryl alcohol (VA) into the medium considerably increased the decolouration rate in SS cultivation. However, the addition of VA had no effect in the nylon cultivation. Thin layer chromatography (TLC) revealed that RB5 was transformed into one metabolite after 24 h. UV-vis spectroscopy and Fourier Transform Infrared (FT-IR) also confirmed the biodegradation of RB5. Toxicity of RB5 solutions before and after fungal treatment was assayed using Sinorhizobium meliloti as a sensitive soil microorganism. P. chrysosporium transformed the toxic dye RB5 into a non-toxic product.     

Advanced glycation end products enhance expression of pro-apoptotic genes and stimulate fibroblast apoptosis through cytoplasmic and mitochondrial pathways

Both aging and diabetes are characterized by the formation of advanced glycation end products (AGEs). Both exhibit other similarities including deficits in wound healing that are associated with higher rates of fibroblast apoptosis. In order to investigate a potential mechanism for enhanced fibroblast apoptosis in diabetes and aged individuals, experiments were carried out to determine whether the predominant advanced glycation end product in skin, N-epsilon-(carboxymethyl) lysine (CML)-collagen, could induce fibroblast apoptosis. In vivo experiments established that CML-collagen but not unmodified collagen induced fibroblast apoptosis and that apoptosis was dependent upon caspase-3, -8, and -9 activity. In vitro experiments demonstrated that CML-collagen but not control collagen induced a time- and dose-dependent increase in fibroblast apoptosis. By use of blocking antibodies, apoptosis was shown to be mediated through receptor for AGE signaling. AGE-induced apoptosis was largely dependent on the effector caspase, caspase-3, which was activated through both cytoplasmic (caspase-8-dependent) and mitochondrial (caspase-9) pathways. CML-collagen had a global effect of enhancing mRNA levels of pro-apoptotic genes that included several classes of molecules including ligands, receptors, adaptor molecules, mitochondrial proteins, and others. However, the pattern of expression was not identical to the pattern of apoptotic genes induced by tumor necrosis factor alpha.     

Identification and determination of extracellular phytate-degrading activity in actinomycetes

In this study 97 soil samples from different soil ecosystems were collected. The initial screening was performed on modified glycerol arginine agar (MGAA) to isolate common actinomycetes and on modified MGA-SE (MMGA-SE) to isolate rare actinomycetes. Sixty-seven isolates potentially producing extracellular phytate-degrading activity were identified. The potential to dephosphorylate phytate was confirmed in liquid culture for 46.3 % of the isolates. 12 strains were selected for a direct determination of their phytate-degrading capacity. The results highlighted that the selected isolates produced extracellular phytate-degrading activity; however their capacity in InsP(6) degradation was different. In addition the fermentation medium had an effect on the extent of phytate degradation. Some enzymatic properties of the phytases from isolate No. 43 and isolate No. 63 were determined after obtaining phytase-enriched samples. The enzymes had maximum phytate-degrading capability at 55 °C and pH 5 (isolate No. 43) and 37 °C and pH 7 (isolates No. 63), respectively. Due to their properties, the phytase of isolate No. 43 behaves like a histidine acid phytase, whereas the phytase of No. 63 showed similar enzymatic properties to the phytase of lily. To our knowledge, the results from this study demonstrated for the first time that actinomycetes produce extracellular phytate-degrading activity. By 16SrRNA sequencing, the more closely studied phytase producers were identified as Streptomyces sp. Isolate No. 43 showed 98 % identity to Streptomyces alboniger and S. venezuelae, while isolate No. 63 exhibited 98 % sequence identity to S. ambofaciens and S. lienomycini.     

The many faces of ubiquitinated histone H2A: insights from the DUBs

Increasing knowledge on the cell cycle deregulations in cancers has promoted the introduction of phytochemicals, which can either modulate signaling pathways leading to cell cycle regulation or directly alter cell cycle regulatory molecules, in cancer therapy. Most human malignancies are driven by chromosomal translocations or other genetic alterations that directly affect the function of critical cell cycle proteins such as cyclins as well as tumor suppressors, e.g., p53. In this respect, cell cycle regulation and its modulation by curcumin are gaining widespread attention in recent years. Extensive research has addressed the chemotherapeutic potential of curcumin (diferuloylmethane), a relatively non-toxic plant derived polyphenol. The mechanisms implicated are diverse and appear to involve a combination of cell signaling pathways at multiple levels. In the present review we discuss how alterations in the cell cycle control contribute to the malignant transformation and provide an overview of how curcumin targets cell cycle regulatory molecules to assert anti-proliferative and/or apoptotic effects in cancer cells. The purpose of the current article is to present an appraisal of the current level of knowledge regarding the potential of curcumin as an agent for the chemoprevention of cancer via an understanding of its mechanism of action at the level of cell cycle regulation. Taken together, this review seeks to summarize the unique properties of curcumin that may be exploited for successful clinical cancer prevention.     

人热休克蛋白gp96基因的克隆及其在大肠杆菌中的表达与纯化

热休克蛋白gp96是热休克蛋白90家族成员,能够引起非特异性和特异性免疫反应。得到大量高纯度的蛋白质是研究开发gp96的关键。然而重组的gp96容易在E．coli中降解,并在一定条件下形成多聚体。实验先将人gp96基因克隆到pET-30a载体上并在E．coli Blstar中表达,再经过亲和层析、阴离子交换、分子筛分别纯化gp96。最终去掉了大部分的降解片段和多聚体,得到一定量的可溶性gp96,为进一步研究其结构和功能打下一定的基础。     

干扰素研究及应用进展

1957年,英国科学家Isaacs和Lindenmann利用鸡胚绒毛尿囊研究流感干扰现象时,发现一种能够干扰病毒繁殖的物质,称之为干扰素（IFN）,由于干扰素对许多疾病有很好的治疗作用,一直是医学领域研究的重要物质之一。现在干扰素已成功地用于肝炎、肿瘤治疗等方面。为了充分发挥干扰素的作用,人们稍用基因工程的方法来对干扰素的产量及功效进行改进,已达到更好的应用,因此基因工程干扰素越来越多地成了研究的重点。     

苹果园光能截获率的数学模型

应用气象学原理推导了不同纬度、不同栽植行向、不同树形的苹果园光能截获率的数学模型,给出在保证树冠基部外围日照时间大于25％总日照时间的条件下,生长季中充分截获光能的最佳树形、行距、冠高、冠径的优化组合方案。实例分析表明,计算结果与专家经验基本一致。本研究为果园合理栽植,充分利用光能,合理整形修剪提供理论依据与参考方案。     

Detection of plasmid-mediated quinolone resistance in clinical isolates of Enterobacteriaceae strains in Hamadan,West of Iran

Plasmid mediated quinolone resistance (PMQR) determinants have arisen as a significant concern in recent years. The aim of this study was screening of resistant-clinical isolates to fluoroquinolone antibiotics and detection of qnr and aac(6′)-Ib-cr genes.For this purpose we collected 100 fluoroquinolone-resistant Enterobacteriaceae which were from 3 hospitals in Hamadan, west provinces of Iran, between October 2012 and June 2013. The all samples were identified by biochemical tests and confirmed by PCR method. Antimicrobial susceptibility to 14 antimicrobial agents including levofloxacin and ciprofloxacin were determined by disk diffusion methods and ciprofloxacin MIC was obtained by broth microdilution method as Clinical Laboratory Standards Institute (CLSI) recommendations. The isolates were screened for the presence of qnrA, qnrB, qnrS and aac(6′)-Ib-cr genes using PCR assay. Among the screened isolates, 64 strains (64%) of Escherichia coli, 23 strains (23%) of Klebsiella pneumoniae, 13 strains (13%) of Proteus mirabilis were collected as quinolone-resistant isolates. out of 100 isolates, two (2%) were positive for qnrS, seventeen (17%) isolates were positive for qnrB and we did not find qnrA gene in any of the isolates. There were also 32 positive isolates for aac(6′)-Ib-cr determinant. We described the prevalence of qnr and aac(6′)-Ib-cr genes in fluoroquinolone-resistant Enterobacteriaceae in Hamadan city. The carriage rate of multidrug-resistant Enterobacteriaceae in healthy people in Hamadan City is extremely high. Moreover, genes encoding transferable quinolones, in particular aac(6′)-Ib-cr, are highly prevalent in these strains.     

Brucellosis Causes Alteration in Trace Elements and Oxidative Stress Factors

Brucellosis is regarded as one of the most common diseases among humans and livestock. In the present study, we aimed to assess the effect of this disease on the level of various cations including copper (Cu), manganese (Mn), zinc (Zn), and magnesium (Mg) as well as oxidative stress status in the serum of people suffering from brucellosis. The present case-study was carried out on 40 patients with brucellosis (case) and 20 healthy people (control). Blood specimens were taken from all the people and the level of essential trace elements and oxidative stress status were measured. The serum level of copper in the case group (165.39 ± 43.19 μg/dl) was significantly higher compared with that in the control group (122.12 ± 28.88 μg/dl). Whereas the serum level of zinc was significantly lower in the case group compared with that in the control group (76.47 ± 28.88 vs. 92.85 ± 23.16 μg/dl). The manganese and magnesium serum levels did not differ significantly between the two groups. Furthermore, total antioxidant capacity level was significantly lower in the case group (122.12 ± 28.22 μmol/ml) than that in the control group (3.08 ± 0.12 μmol/ml) and the level of serum malondialdehyde was significantly higher in the case group (7.20 ± 0.23 mmol/ml) than that in the control group (4.0 ± 0.19 mmol/ml). Brucellosis can cause alteration in the serum level of essential trace elements. Moreover, the present study indicated that brucellosis produces oxidative stress in patients.