The discovery of new deep-sea hydrothermal vent communities in the southern ocean and implications for biogeography

Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised.     

Evaluation of the use of malic acid decarboxylase‐deficient starter culture in NaCl‐free cucumber fermentations to reduce bloater incidence

Aims

Accumulation of carbon dioxide (CO₂) in cucumber fermentations is known to cause hollow cavities inside whole fruits or bloaters, conducive to economic losses for the pickling industry. This study focused on evaluating the use of a malic acid decarboxylase (MDC)‐deficient starter culture to minimize CO₂ production and the resulting bloater index in sodium chloride‐free cucumber fermentations brined with CaCl₂.

Methods and Results

Attempts to isolate autochthonous MDC‐deficient starter cultures from commercial fermentations, using the MD medium for screening, were unsuccessful. The utilization of allochthonous MDC‐deficient starter cultures resulted in incomplete utilization of sugars and delayed fermentations. Acidified fermentations were considered, to suppress the indigenous microbiota and favour proliferation of the allochthonous MDC‐deficient Lactobacillus plantarum starter cultures. Inoculation of acidified fermentations with L. plantarum alone or in combination with Lactobacillus brevis minimally improved the conversion of sugars. However, inoculation of the pure allochthonous MDC‐deficient starter culture to 10⁷ CFU per ml in acidified fermentations resulted in a reduced bloater index as compared to wild fermentations and those inoculated with the mixed starter culture.

Conclusions

Although use of an allochthonous MDC‐deficient starter culture reduces bloater index in acidified cucumber fermentations brined with CaCl₂, an incomplete conversion of sugars is observed.

Significance and Impact of the Study

Economical losses due to the incidence of bloaters in commercial cucumber fermentations brined with CaCl₂ may be reduced utilizing a starter culture to high cell density.     

Oxidative stress is markedly elevated in lecithin:cholesterol acyltransferase-deficient mice and is paradoxically reversed in the apolipoprotein E knockout background in association with a reduction in atherosclerosis.

Complete lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare cause of severe hypoalphalipoproteinemia, but the affected subjects are surprisingly not particularly prone to premature coronary heart disease. We studied oxidative stress in lcat-/- mice and their cross-breed with apolipoprotein-E knockout mice (apoE-/-xlcat-/-) by measuring vascular ring superoxide production and plasma phospholipid (PL)-bound F2-isoprostane levels and their relationship with aortic atherosclerosis. Compared with wild type control (lcat+/+), lcat-/- and lcat+/- mice showed a 4.9- (p = 0.003) and a 2.1-fold (p = 0.04) increase in plasma PL-F2-isoprostane levels, respectively. There was also a 3.6- (p < 0.0001) and 2.9-fold (p = 0.003) increase in the area under the curve for the aortic ring superoxide excursion by lucigenin-derived chemiluminescence. A comparison of apoE-/-xlcat+/+ mice with wild type control mice showed a more modest 2.1- (p = 0.04) and 2.2-fold (p < 0.00001) increase in these respective markers. Surprisingly, the apoE-/-xlcat-/- mice showed a paradoxical normalization in both oxidation markers. Furthermore, by fast protein liquid chromatography separation, we observed an associated retention and redistribution of serum paraoxonase activities to the non-high density lipoprotein fractions in both the apoE-/-xlcat-/- and apoE-/-xlcat+/- mice. Aortic atherosclerotic lesions in male apoE-/-xlcat-/- and apoE-/-xlcat+/- mice were reduced by 52 (p = 0.02) and 24% (p = 0.46), respectively. Our data suggest that LCAT-deficient mice are associated with an increased oxidative stress that is paradoxically reversed in a hyperlipidemic background, possibly due to the redistribution of paraoxonase. This modulation of oxidative stress may in part contribute to the reduced atherosclerosis seen in the apoE-/- xlcat-/- mice.     

Serum 5-androstene-3 beta,17 beta-diol sulphate and 5 alpha-androstane-3 alpha,17 beta-diol sulphate in hirsute females with polycystic ovarian disease

Serum sulphates of 5-androstene-3 beta,17 beta-diol (5-ADIOL-S), 5 alpha-androstane-3 alpha,17 beta-diol (3 alpha-DIOL-S) and dehydroepiandrosterone (DHEA-S), unconjugated androstene-dione (AD) and testosterone (T), sex hormone binding globulin (SHBG), free androgen index (FAI), 17 alpha-hydroxyprogesterone (17OHP), luteinising hormone (LH) and follicle stimulating hormone (FSH) were measured by specific radioimmunoassay in 28 hirsute women with polycystic ovarian disease (PCO) and in normal women (n = 73). Mean levels of steroids measured were significantly elevated, and SHBG significantly depressed, in the women with PCO with values (mean +/- SE) for 5-ADIOL-S (516 +/- 51 vs 267 +/- 10 nmol/l), 3 alpha-DIOL-S (130 +/- 9 vs 52 +/- 2 nmol/l), DHEA-S (7.3 +/- 0.5 vs 4.4 +/- 0.2 mumol/l), AD (11.3 +/- 1.1 vs 3.4 +/- 0.2 nmol/l), T (3.3 +/- 0.2 vs 1.5 +/- 0.1 nmol/l) and 17OHP (5.1 +/- 0.8 vs 2.8 +/- 0.2 nmol/l). SHBG levels were 31 +/- 2.9 vs 65 +/- 2.5 nmol/l, and the free androgen index [100 x T (nmol/l) divided by (SHBG nmol/l)] was 12.5 +/- 1.4 vs 2.4 +/- 0.1. The mean LH to FSH ratio was also elevated at 2.8 +/- 0.3. These studies suggest that the measurement of 5-ADIOL-S and DHEA-S may indicate adrenal gland involvement in PCO while 3 alpha-DIOL-S appears to be a reflection of peripheral androgen metabolism. A comprehensive biochemical profile of PCO should thus include the analysis of these sulphoconjugates as well as unconjugated steroids.     

低温对植物叶片中超氧物歧化酶、过氧化氢酶和过氧化氢水平的影响

番茄和鸡蛋果叶片中可提取的SOD活性不受低温的影响。在电泳谱带上SOD主同工酶带被氰化物而不被低温抑制,次同工酶带在低温下不稳定,且活性很低,它的变化不影响总的SOD活性。一些冷敏感植物叶片中CAT活性被低温抑制,而H_2O_3水平在低温下稳定或有增加,这可能使毒性更强的羟基离子(OH·)易于形成。     

Exploiting a water network to achieve enthalpy-driven,bromodomain-selective BET inhibitors

Within the last decade, the Bromodomain and Extra-Terminal domain family (BET) of proteins have emerged as promising drug targets in diverse clinical indications including oncology, auto-immune disease, heart failure, and male contraception. The BET family consists of four isoforms (BRD2, BRD3, BRD4, and BRDT/BRDT6) which are distinguished by the presence of two tandem bromodomains (BD1 and BD2) that independently recognize acetylated-lysine (KAc) residues and appear to have distinct biological roles. BET BD1 and BD2 bromodomains differ at five positions near the substrate binding pocket: the variation in the ZA channel induces different water networks nearby. We designed a set of congeneric 2- and 3-heteroaryl substituted tetrahydroquinolines (THQ) to differentially engage bound waters in the ZA channel with the goal of achieving bromodomain selectivity. SJ830599 (9) showed modest, but consistent, selectivity for BRD2-BD2. Using isothermal titration calorimetry, we showed that the binding of all THQ analogs in our study to either of the two bromodomains was enthalpy driven. Remarkably, the binding of 9 to BRD2-BD2 was marked by negative entropy and was entirely driven by enthalpy, consistent with significant restriction of conformational flexibility and/or engagement with bound waters. Co-crystallography studies confirmed that 9 did indeed stabilize a water-mediated hydrogen bond network. Finally, we report that 9 retained cytotoxicity against several pediatric cancer cell lines with EC₅₀ values comparable to BET inhibitor (BETi) clinical candidates.