Pachypodol attenuates Perfluorooctane sulphonate-induced testicular damage by reducing oxidative stress

Perfluorooctane sulfonate (PFOS) is an endocrine disruptor chemical (EDC) with potentially adverse effects on the male reproductive system. Pachypodol (5,4′-dihydroxy-3,7,3′-trimethoxyflavone) is a promising flavonoid isolated from Pogostemon cablin (Blanco) Benth that shows a broad range of pharmacological properties. However, the potential curative effects of pachypodol on testicular toxicity are not available until now. Therefore, this research was proposed to examine the efficiency of pachypodol against PFOS-induced testicular toxicity in adult male rats. The experiments were conducted on Sprague-Dawley rats (n = 48), which were equally distributed into four groups: control, PFOS (20 mg/kg), PFOS + Pachypodol (20 mg/kg + 10 mg/kg respectively), and Pachypodol (10 mg/kg). After 56 days of treatment, testes were excised by slaughtering rats, weighed, and stored till further analysis. The estimated parameters include biochemical markers, spermatogenic indices, hormonal and histopathological profiles. PFOS exposure disturbed the biochemical profile by altering the antioxidant/oxidant balance. For instance, it decreased the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GSR) while increasing the concentration of reactive oxygen species (ROS) and level of thiobarbituric acid reactive substances (TBARS). PFOS intoxication also led to a notable decline in viability, motility, epididymal sperm count, and the number of HOS coiled-tail sperms, whereas the higher level of abnormality in the head, mid-piece, and tail of sperms were observed. Besides, it lowered luteinizing hormone (LH), follicle-stimulating hormone (FSH), and plasma testosterone. In addition, PFOS exposure led to histopathological damages in testicles. However, pachypodol treatment potently alleviated all the illustrated impairments in testes. Conclusively, our results demonstrate the promising free-radical scavenging activity of pachypodol, a novel phytochemical, against the PFOS-instigated testicular dysfunctions.     

低双乙酰啤酒酵母菌株BEZ112的选育

以啤酒酿造生产菌株啤酒酵母(Saccharomyces cerevisiae)FB作为出发菌株,用甲基磺酸乙酯(EMS)诱变,经分离筛选得到一株优良的啤酒酵母菌株BEZ112。该菌株的絮凝性、发酵度、酒精度、发酵液的总酯和总高级醇的含量等特性保持了亲株的优良性状。但以12°Bx麦芽汁为培养基用500mL三角瓶在12℃下发酵,该菌株发酵至第4d,发酵液中的双乙酰含量达到峰值(0.291mg/L),比出发菌株FB发酵4d的峰值降低了30％,发酵至第8d,BEZ112发酵液中的双乙酰含量比出发菌株FB的降低了23％。以12°Bx麦芽汁为培养基用500L罐在12℃下发酵8d,BEZ112发酵液中的双乙酰含量(0.091mg/L)比出发菌株FB的(0.124mg/L)降低了27％。发酵得到的啤酒口感纯正清爽。     

LAS和5种洗衣粉对多刺裸腹氵蚤的毒性研究

采用多刺裸腹氵蚤（Ｍｏｉｎａｍａｃｒｏｃｏｐａ）对ＬＡＳ（十二烷基苯磺酸钠）和５种洗衣粉的毒性进行了研究。结果显示,这些物质能够抑制多刺裸腹氵蚤的运动,并且造成氵蚤的大量死亡。４８小时所测得的半数致死浓度（ＬＣ５０）,ＬＡＳ为７１ｐｐｍ;ＷＣ、ＦＣ、ＢＬ、ＯＭ、ＴＺ洗衣粉的ＬＣ５０分别为６６、５５、５１、４２和３５５ｐｐｍ。     

一株十二烷基苯磺酸钠降解菌的分离鉴定及降解特性研究

从受污染河水中筛选分离得到一株能以十二烷基苯磺酸钠(Sodiumdodecylbenzenesulfonate,SDBS)为唯一碳源和能源生长的菌株WZR-A。经对其形态特征、生理生化、以及16SrDNA序列分析,将WZR-A初步鉴定为人苍白杆菌(Ochrobactrumanthropi)。研究表明该菌株利用SDBS生长的最适温度为30℃,最适pH为7·0。SDBS浓度低于400mg/L时菌株对SDBS的降解率可在80%以上。菌株细胞蛋白SDS-PAGE结果显示,菌株在SDBS诱导前后的细胞蛋白组成有明显差异。酶的定域试验表明,该菌株的相关降解酶为胞内酶。相关降解酶活性及降解底物测试结果表明,该菌株可能通过邻位途径裂解芳环并具有对多种芳香族化合物降解的能力。此外,利用质粒检测和消除试验发现菌株WZR-A中含有大质粒且该菌株的相关降解基因初步定位于该质粒。     

十二烷基苯磺酸钠对引发内置物感染表皮葡萄球菌生物被膜的作用

【背景】随着医用内置物的广泛使用,由表皮葡萄球菌生物被膜导致的医院获得性感染不断增多,目前鲜见关于表面活性剂针对表皮葡萄球菌生物被膜作用的报道。【目的】通过研究阴离子型表面活性剂十二烷基苯磺酸钠(sodium dodecyl benzene sulfonate,SDBS)分别对ATCC 35984 (产膜表皮葡萄球菌标准株)生物被膜的清除、生物被膜内细菌代谢和形成生物被膜的关键物质多糖胞间黏附素(polysaccharide intercellular adhesion,PIA)产生的影响,为临床使用SDBS防治由表皮葡萄球菌生物被膜引起的相关感染提供可靠的理论及实践依据。【方法】利用XTT减低法,评价SDBS对ATCC 35984已形成生物被膜的清除效率及对生物被膜内细菌代谢的影响;激光共聚焦显微镜观察SDBS对生物被膜作用的效果;采用刚果红培养基观察SDBS对PIA产生的影响。【结果】浓度为256、128、64、32、16 mg/L的SDBS在作用6、12、24 h时,对ATCC 35984的生物被膜均有显著的清除效率(P<0.01);浓度为32 mg/L时对生物被膜内细菌的...     

An Introduction to Worm Lab: from Culturing Worms to Mutagenesis

This protocol describes procedures to maintain nematodes in the laboratory and how to mutagenize them using two alternative methods: ethyl methane sulfonate (EMS) and 4, 5'', 8-trimethylpsoralen combined with ultraviolet light (TMP/UV). Nematodes are powerful biological systems for genetics studies because of their simple body plan and mating system, which is composed of self-fertilizing hermaphrodites and males that can generate hundreds of progeny per animal. Nematodes are maintained in agar plates containing a lawn of bacteria and can be easily transferred from one plate to another using a pick. EMS is an alkylating agent commonly used to induce point mutations and small deletions, while TMP/UV mainly induces deletions. Depending on the species of nematode being used, concentrations of EMS and TMP will have to be optimized. To isolate recessive mutations of the nematode Pristionchus pacificus, animals of the F2 generation were visually screened for phenotypes. To illustrate these methods, we mutagenized worms and looked for Uncoordinated (Unc), Dumpy (Dpy) and Transformer (Tra) mutants.     

Membrane permeability transition promoted by phosphate enhances 1-anilino-8-naphthalene sulfonate fluoresence in calcium-loaded liver mitochondria

Phosphate and a number of other compounds induce membrane permeability transition (MBT) in Ca²⁺-loaded mitochondria. 1-Anilino-8-naphthalene sulfonate (ANS) was used as a fluorescent probe to investigate perturbations on the inner membrane during MBT. Induction of MBT caused ANS fluoresence enhancement with a biphasic rate that reached a plateau. The enhancement is analogous to that reported for de-energization of mitochondria. The fluoresence level was independent of whether ANS was added before or at different times after phosphate. In the absence of ANS, fluorescence was low and remained unchanged. The initial time course of MBT, as followed by large-amplitude swelling, was similar to that of fluorescence enhancement. Ruthenium red, EGTA, ADP, and cyclosporin A inhibited the enhancement. Only EGTA + ADP (or ATP) reversed the enhancement when added after phosphate. Efflux of matrix Ca²⁺ by sodium acetate or A23187 did not alter ANS fluoresence. The binding parameters (K _d and number of binding sites) were not significantly different, but the fluorescence maximum was more than doubled after MBT. Although the flourescence of bound ANS showed a nonlinear relationship, it was always higher (73.0 +/- 19.0%) after reaching the plateau. Since ANS binding to membranes is nonspecific, the exact mechanism of the enhanced fluorescence is not apparent. The dependence of the initial rate of fluorescence enhancement on Ca²⁺ concentration was nonlinear, with 45 µM at half-maximal rate. The dependence on phosphate was hyperbolic with 0.7 mM at half-maximal rate, which is close to theK _m value of phosphate carrier. The kinetics is compatible with Ca²⁺ binding to some membrane component(s) during MBT and cause ANS fluorescence enhancement. It is suggested that the bilayer-nonbilayer (hexagonal₁₁) transition consequent to Ca²⁺ binding to proteinphospholipid domains containing cardiolipin may play a role in fluorescence enhancement and MBT.     

INFLUENCE OF CELL WALL COMPOSITION ON THE RESISTANCE OF TWO CHLORELLA SPECIES (CHLOROPHYTA) TO DETERGENTS1

The influence of dodecylbenzene sulfonate (DBS) and Triton X-100 (TX-100) was examined on two species of Chlorella exhibiting conspicuous differences in cell wall composition. Chlorella emersonii has both a classical polysaccharidic wall and a thin trilaminar outer wall (TLS) composed of nonhydrolyzable macromolecules. Chlorella vulgaris lacks a TLS. Photosynthetic capacity was measured following short exposures (1 h) of the algae at different physiological stages to high DBS and TX-100 concentrations, up to 1 g·L^?1. Comparisons with untreated controls indicated that 1) the presence of a TLS in C. emersonii was associated with a very high resistance to the anionic (DBS) and nonionic (TX-100) detergents at all growth stages, and net photosynthesis was not significantly affected in that species, 2) a high toxicity, particularly pronounced with TX-100, was observed for actively growing cells of the TLS-devoid species, C. vulgaris, and 3) aging exerted a protective influence, especially efficient against DBS, on the latter species. Additional observations, including fluorescence spectra and high-performance liquid chromatography pigment analyses, were conducted following short exposures of actively growing cells. Fluorescence emission spectra revealed that the chlorophyll a-protein complexes in thylakoid membranes were not substantially affected by DBS and TX-100, even in the case of C. vulgaris. In sharp contrast, fluorescence excitation spectra on the latter species showed 1) that excitation transfer from antenna pigments to chlorophyll a in reaction centers was substantially altered with both detergents and 2) that the two detergents affected different parts of the photosynthetic system of the TLS-devoid species. Analyses of C. vulgaris extracts indicated significant decreases in pigment content following exposure to DBS and, to a lesser extent, to TX-100. Longer exposure experiments (1 day) were conducted with actively growing algae. The TLS-containing species still showed a very high resistance and no important changes in photosynthetic capacity compared to cells exposed for 1 h. For the sensitive TLS-devoid species, the detrimental influence of TX-100, already very high after 1 h, was not increased. DBS toxicity was markedly increased and may reflect a lower uptake rate of DBS by C. vulgaris. Taken together, these observations confirm the important protective role of TLS against detergents. They also provide information on the factors controlling detergent toxicity in the sensitive, TLS-devoid species and on the different modes of action of DBS and TX-100 on its photosynthetic system. Such large differences in microalgal sensitivity to detergents, related to TLS occurrence, should have important consequences for the selection of suitable species in toxicity tests.