Enzyme Production by Species of Cephalosporium

The culture filtrates of ten species of Cephalosporium, which had been grown under conditions of submerged culture, were tested for enzymatic activity against each of seven substrates. The latter included casein, gelatin, milk, hemoglobin, human plasma clots, starch, and N-acetyl-β-D-glucosaminide. All organisms tested were active, but to varying degrees. The most pronounced activities were obtained against the proteinaceous substrates. Two unidentified species of Cephalosporium exhibited the highest over-all activities, but no one organism predominated for all enzymatic functions. The ability of a filtrate to degrade a specific substrate was not always correlated with its ability to attack other substrates. The fibrinolytic properties of three of the cephalosporia were of particular interest. α-Amylase activity was not significant. The results obtained suggest the possible use of selected species of Cephalosporium as sources of a variety of microbial enzymes.     

Cortisol stress response and histopathological alteration index in Clarias gariepinus exposed to sublethal concentrations of Qua Iboe crude oil and rig wash

The histological effect on and stress response of post juvenile Clarias gariepinus exposed to Qua Iboe crude oil and rig wash were investigated. Fish weighing 60–90 g and measuring 16–18 cm were exposed for 7–28 days to 8.00 ml^?1 Qua Iboe crude oil and 0.0018 ml^–1 rig wash, both being 0.1 of the 96 hr LC₅₀. Blood samples of C. gariepinus were collected every seven days and evaluated for stress by measuring cortisol concentration. The gills and liver were studied and scored for Gill Alteration Index (GAI) and Hepatic Alteration Index (HAI), respectively. There was an increase in cortisol level up to the 7th and 14th day among the group exposed to Qua Iboe crude oil, with a decrease on the 21st and 28th day. The rig wash group increased in cortisol level up to the 7th day and decreased slightly on the 14th day, after which the trend became irregular. The toxic effects of the Qua Iboe crude oil and rig wash were time dependent, as shown by the histopathological alteration index (HAI) of gill and liver. After 28 days of exposure, the gills had irreparable damage due to high frequency of cellular necrosis and degeneration, whereas the liver had from moderate to severe damage due to the high frequency of cellular degeneration and inflammation. Qua Iboe crude oil and rig wash are both toxic to C. gariepinus, therefore their indiscriminate discharge to the environment must be discouraged.     

The role of platelet ice microalgae in seeding phytoplankton blooms in Terra Nova Bay (Ross Sea,Antarctica): a mesocosm experiment

The aim of this study was to assess the role of platelet ice microalgal communities in seeding pelagic blooms. Nutrient dynamics, microalgal biomass, photosynthetic parameters, cell densities and species succession were studied in two mesocosm experiments, designed to simulate the transition of microalgal communities from platelet ice habitat to pelagic conditions. The microalgal assemblages were dominated by diatoms, 70% of which were benthic species such as Amphiprora kufferathii, Nitzschia stellata, and Berkeleya adeliensis. Photoacclimation of benthic species was inadequate also at relatively low irradiances. Exceptional growth capacity at different light levels was observed for pelagic species such as Fragilariopsis cylindrus and Chaetoceros spp. which may be important in seeding blooms at ice breakup. Fragilariopsis cylindrus showed high growth rates both at 65 and 10% of incident light and in nutrient replete as well as in nutrient depleted conditions. Five days after inoculation, phytoplankton biomass increased and nutrient concentrations decreased in both light conditions. Nutrient uptake rates were up to 9.10 μmol L⁻¹ d⁻¹ of TIN in the high light tank and 6.18 μmol L⁻¹ d⁻¹ in the low light tank and nutrient depletion in the high light tank occurred 3 days prior to depletion in the low light tank. At nutrient depletion, biomass concentrations were similar in both tanks, 30 and 34 μg Chla L⁻¹. This article belongs to a special topic: Five articles on Sea-ice communities in Terra Nova Bay (Ross Sea), coordinated by L. Guglielmo and V. Saggiomo, appear in this issue of Polar Biology. The studies were conducted in the frame of the National Program of Research in Antarctica (PNRA) of Italy.     

Amine substituted N-(1H-benzimidazol-2ylmethyl)-5,6,7,8-tetrahydro-8-quinolinamines as CXCR4 antagonists with potent activity against HIV-1

Several novel amine substituted N-(1H-benzimidazol-2ylmethyl)-5,6,7,8-tetrahydro-8-quinolinamines were synthesized which had potent activity against HIV-1. The synthetic approaches adopted allowed for variation of the substitution pattern and resulting changes in antiviral activity are highlighted. This led to the identification of compounds with low and sub-nanomolar anti-HIV-1 activity.     

非酒精性脂肪肝大鼠PPARα基因表达及脂代谢和胰岛素水平的变化

目的观察非酒精性脂肪肝（NAFLD）大鼠肝组织中PPARα基因的表达,并用PPARct激动剂进行干预,探讨其与胰岛素抵抗、脂代谢紊乱的关系。方法大鼠随机分为①正常对照组、②高脂模型组、③PPARα激动剂干预组,利用高脂饮食建立大鼠非酒精性脂肪肝模型。12周后,检测大鼠血脂、肝功能、血糖、胰岛素水平及胰岛素抵抗指数;RT-PCR法分析PPARα基因的表达;观察肝脏的形态学改变。结果PPARa激动剂可降低NAFLD大鼠转氨酶、血脂水平及胰岛素抵抗指数,可促进NAFLD大鼠中PPARa基因的表达;肝脏形态学明显改善。结论PPARα激动剂能改善NAFLD大鼠脂质代谢紊乱,有明显的保肝降酶作用,具有适度的胰岛素增敏作用。PPARα及其配体在NAFLD发病机制及治疗中的进一步深入研究,将为临床防治NAFLD提供新的思路。     

SD雌性大鼠性发育早期性器官等脏器和性激素的动态变化

目的探讨正常SD雌性大鼠性成熟前不同日龄段的脏器与促黄体生成素（LH）、促卵泡素（FSH）、雌二醇（E2）等性激素的变化及其关系。方法从生产群中取出60窝密度状态一致的SD大鼠,在不同日龄随机选取雌性大鼠,检测15、25、32、40日龄时大鼠体重、主要脏器指数,子宫、卵巢组织变化和15、25、32、40、60日龄大鼠血清LH、FSH、E2水平。结果记录了SD雌性大鼠性成熟前各脏器指数和卵巢、子宫组织变化,结果显示大鼠卵巢、子宫的增长速度大于体重的增长,而其他脏器增速大都小于体重的增长。本研究还记录了血清LH、FSH、E2水平在不同日龄段的变化规律,表明血清LH、E2浓度在32日龄时出现较为明显升高。结论不同日龄大鼠脏器指数的动态变化提示大鼠性器官在性发育早期得到机体的优先发育。血清LH、E2水平在32日龄时有了明显升高,提示性腺轴功能已经激活。60日龄大鼠血清性激素水平的波动类似于动情周期的规律性变化,推测大鼠在60日龄前即已进入性成熟,这些结果将为大鼠性发育的相关研究提供重要的参考数据。     

Developing human laboratory models of smoking lapse behavior for medication screening

Use of human laboratory analogues of smoking behavior can provide an efficient, cost-effective mechanistic evaluation of a medication signal on smoking behavior, with the result of facilitating translational work in medications development. Although a number of human laboratory models exist to investigate various aspects of smoking behavior and nicotine dependence phenomena, none have yet modeled smoking lapse behavior. The first instance of smoking during a quit attempt (i.e. smoking lapse) is highly predictive of relapse and represents an important target for medications development. Focusing on an abstinence outcome is critical for medication screening as the US Food and Drug Administration approval for cessation medications is contingent on demonstrating effects on smoking abstinence. This paper outlines a three-stage process for the development of a smoking lapse model for the purpose of medication screening. The smoking lapse paradigm models two critical features of lapse behavior: the ability to resist the first cigarette and subsequent ad libitum smoking. Within the context of the model, smokers are first exposed to known precipitants of smoking relapse (e.g. nicotine deprivation, alcohol, stress), and then presented their preferred brand of cigarettes. Their ability to resist smoking is then modeled and once smokers 'give in' and decide to smoke, they participate in a tobacco self-administration session. Ongoing and completed work developing and validating these models for the purpose of medication screening is discussed.     

Population dynamic of the extinct European aurochs: genetic evidence of a north-south differentiation pattern and no evidence of post-glacial expansion

Background

Various evolutionary models have been proposed to interpret the fate of paralogous duplicates, which provides substrates on which evolution selection could act. In particular, domestication, as a special selection, has played important role in crop cultivation with divergence of many genes controlling important agronomic traits. Recent studies have indicated that a pair of duplicate genes was often sub-functionalized from their ancestral functions held by the parental genes. We previously demonstrated that the rice cell-wall invertase (CWI) gene GIF1 that plays an important role in the grain-filling process was most likely subjected to domestication selection in the promoter region. Here, we report that GIF1 and another CWI gene OsCIN1 constitute a pair of duplicate genes with differentiated expression and function through independent selection.

Results

Through synteny analysis, we show that GIF1 and another cell-wall invertase gene OsCIN1 were paralogues derived from a segmental duplication originated during genome duplication of grasses. Results based on analyses of population genetics and gene phylogenetic tree of 25 cultivars and 25 wild rice sequences demonstrated that OsCIN1 was also artificially selected during rice domestication with a fixed mutation in the coding region, in contrast to GIF1 that was selected in the promoter region. GIF1 and OsCIN1 have evolved into different expression patterns and probable different kinetics parameters of enzymatic activity with the latter displaying less enzymatic activity. Overexpression of GIF1 and OsCIN1 also resulted in different phenotypes, suggesting that OsCIN1 might regulate other unrecognized biological process.

Conclusion

How gene duplication and divergence contribute to genetic novelty and morphological adaptation has been an interesting issue to geneticists and biologists. Our discovery that the duplicated pair of GIF1 and OsCIN1 has experienced sub-functionalization implies that selection could act independently on each duplicate towards different functional specificity, which provides a vivid example for evolution of genetic novelties in a model crop. Our results also further support the established hypothesis that gene duplication with sub-functionalization could be one solution for genetic adaptive conflict.     

In vitro activity of novel dual action MDR anthranilamide modulators with inhibitory activity at CYP-450

Synthesis and in vitro cytotoxicity assays of new anthranilamide MDR modulators have been performed to assess their inhibition potency of the P-glycoprotein (P-gp) transporter. The aromatic spacer group between nitrogen atoms (N1 and N2) in the known inhibitor XR9576 was replaced with a flexible alkyl chain of 2 to 6 carbon atoms in length. 6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinoline and their open-chain N-methylhomoveratrylamine counterparts were shown to be potent P-gp inhibitors. The maximal inhibition was obtained when using an ethyl or propyl spacer. Several compounds were more potent than verapamil and intrinsically less cytotoxic than XR9576. In addition, in vitro metabolism studies of 23a with a subset of human CYP-450 isoforms revealed that, unlike XR9576, 23a inhibited CYP3A4, an enzyme that colocalizes with P-gp in the intestine and contributes to tumor cell chemoresistance by enhancing the biodisposition of anticancer drugs such as paclitaxel toward metabolism. In this context, 22a might be a suitable candidate for further drug development.