A novel cardiolipin-remodeling pathway revealed by a gene encoding an endoplasmic reticulum-associated acyl-CoA:lysocardiolipin acyltransferase (ALCAT1) in mouse

Cardiolipin is a major membrane polyglycerophospholipid that is required for the reconstituted activity of a number of key mitochondrial enzymes involved in energy metabolism. Cardiolipin is subjected to remodeling subsequent to its de novo biosynthesis to attain appropriate acyl composition for its biological functions. Yet, the enzyme(s) involved in the remodeling process have not been identified. We report here the identification and characterization of a murine gene that encodes an acyl-CoA:lysocardiolipin acyltransferase 1 (ALCAT1). Expression of the ALCAT1 cDNA in either insect or mammalian cells led to a significant increase in acyl-CoA:monolysocardiolipin acyltransferase and acyl-CoA: dilysocardiolipin acyltransferase activities that exhibited a dependence upon ALCAT1 enzyme levels. The recombinant ALCAT1 enzyme recognizes both monolysocardiolipin and dilysocardiolipin as substrates with a preference for linoleoyl-CoA and oleoyl-CoA as acyl donors. In contrast, no significant increases in acyltransferase activities by the recombinant ALCAT1 were detected against either glycerol-3-phosphate or a variety of other lysophospholipids as substrates, including lysophosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidylserine. Immunocytohistochemical analysis showed that the ALCAT1 enzyme is localized in the endoplasmic reticulum, which is supported by a significant ALCAT activity in isolated liver and heart microsomes. Northern blot analysis indicates that the mouse ALCAT1 is widely distributed, with the highest expression in heart and liver. In support of a role for ALCAT1 in maintaining heart function, the ALCAT1 gene is conserved among different species of vertebrates, but not in non-atrium organisms. ALCAT1 represents the first identified cardiolipin-remodeling enzyme from any living organism; its identification implies a novel role for the endoplasmic reticulum in cardiolipin metabolism.     

Two new antibacterial sesquiterpenoids from Centipeda minima

Two new guaiane-type sesquiterpene lactones, compounds 1 and 2, along with three known guaianolide- or pseudoguaianolides, were isolated from Centipeda minima (whole plant). Their structures were identified by spectroscopic and mass-spectrometric analyses. The configuration at C5 of the guaiane framework of 1 was rationalized by quantum-mechanical calculations (Table 2). All compounds were found to be active against eight different microbial pathogens (Table 3), with MIC values in the range of 6.25-100 microg/ml.     

Synthesis and analgesic activities of endomorphin-2 and its analogues

Endomorphin-2 (1; H-Tyr-Pro-Phe-Phe-NH2; EM2) and its novel cyclic asparagine (cycloAsn) analogues, H-Tyr-cAsn(CHPh)-Phe-Phe-NH2 (2) and H-Tyr-cAsn(CHMe2)-Phe-Phe-NH2 (3), were synthesized via liquid-phase synthesis. The structures of the products and intermediates were characterized by IR, 1H-NMR, MS, and HR-MS analyses. The antinociceptive activity of EM2 and its cyclic asparagine analogues were assessed in AcOH-induced abdominal constriction tests in mice with i.p. injection. The results show that the antinociceptive activities of EM2 and its cyclic asparagine analogue 2 were higher than those of aspirine and meperidine. Analogue 2 was observed to be a stronger analgesic with dose-dependence than EM2. The test mice did not show any tendency to be addicted while administrated of analogue 2 repeatedly and regularly.     

Genome sequence of duck pathogen Mycoplasma anatis strain 1340

Mycoplasma anatis, a member of the class Mollicutes, is the causative agent of a contagious infectious disease of domestic ducklings, wild birds, and eggs. Increasing reports show that coinfection of M. anatis with Escherichia coli results in substantial economic impacts on the duck farms in China. Here, we announce the first genome sequence of M. anatis.     

Association of single-nucleotide polymorphisms in RHOB and TXNDC3 with knee osteoarthritis susceptibility: two case-control studies in East Asian populations and a meta-analysis

Introduction

Conflicting findings on the association of single nucleotide polymorphisms (SNPs) in RHOB and TXNDC3 with susceptibility to knee osteoarthritis (OA) have been reported in European Caucasians. To examine the associations of these SNPs with OA in East Asian populations and to evaluate their global significance, we conducted two case-control studies in 955 Chinese and 750 Japanese patients.

Methods

We genotyped the previously implicated SNPs rs585017 (in RHOB) and rs4720262 (in TXNDC3) in patients with primary symptomatic knee OA with radiographic confirmation and in matched control individuals, and analyzed their associations. We further conducted a meta-analysis of the study findings together with those of previously reported European studies using the DerSimonian-Laird procedure.

Results

A significant association of RHOB with knee OA was observed in male Chinese patients (P = 0.02). No significant associations were found for RHOB in any other comparisons in the East Asian populations. The association of TXNDC3 was replicated in Chinese female (P = 0.04) and Japanese (P = 0.03) patients, although none of these associations persisted after Bonferroni correction. Significant association (P = 0.02 for the allelic frequency) with nonsignificant heterogeneity was found in the East Asian replication study. No significant association was found in any comparison in the meta-analysis for all studies.

Conclusion

Our study replicates the association, previously reported in European Caucasians, of TXNDC3 with knee OA susceptibility in an East Asian population.     

Effect of rock fragments on the percolation and evaporation of forest soil in Liupan Mountains, China

The water-retaining capacity, percolation and evaporation of stony soil in Liupan Mountains, China, were measured in order to understand the effect of rock fragments on soil hydrological processes. The results indicated that the effective water-retaining capacity of soil is positively related with the volumetric content of rock fragments, but there is no relation between saturated water-retaining capacity and rock fragment content. For the soil layers within 0–40 cm, the steady infiltration rate increases with increasing volumetric content of rock fragments until it reaches the range of 15%–20%, and then it decreases when the rock fragment content further increases. For the soil layers below 40 cm, the steady infiltration rate always increases with increasing rock fragment content. The soil evaporation rate decreases with increasing volumetric content of rock fragments when it varies in the range of 0–20%, while the soil evaporation rate keeps basically stable when the rock fragment content is higher than 20%. The soil evaporation rate shows a rising tendency with increasing size of rock fragments.     

Genetic structure of Brandt’s vole (<Emphasis Type="Italic">Lasiopodomys brandtii</Emphasis>) populations in Inner Mongolia,China, based on microsatellite analysis

Brandt’s vole (Lasiopodomys brandtii) distribution is discontinuous in Inner Mongolia with some populations isolated from others. Recently, some isolated populations have suffered extinction, and the factors responsible remain elusive. Genetic drift is one of the processes affecting population genetic differentiation, and can play a substantial role in the divergence of small, isolated populations. Using seven microsatellite markers, we genotyped four geographically isolated populations of Brandt’s vole, all of which exhibit episodic fluctuations in population density. The results showed a strong genetic differentiation among the geographically distinct populations (total F _ST = 0.124) and in particular, one population (Zhengxiangbaiqi) was isolated from all others (F _ST values were greatest between Zhengxiangbaiqi and other populations). Furthermore, high levels of inbreeding (F _IS values ranged from 0.205 to 0.290) within each distinct population suggest that inbreeding has and is likely occurring in Brandt’s vole populations. These processes can decrease average individual fitness and consequently increase the risk of extinction of the species.     

Effects of phosphate-solubilizing bacteria application on soil phosphorus availability in coal mining subsidence area in Shanxi

The effect of phosphate-solubilizing bacteria (PSB) application on phosphorus (P) availability in reclaimed soil in coal mining subsidence region was investigated. Seven treatments were carried out including control, chicken manure (CM), PSB, PSB + tricalcium phosphate (TCP), CM?+?TCP, PSB?+?ground phosphate rock (GPR) and CM?+?GPR. The results showed soil Olsen-P concentration and phosphatase level as well as the yield of pakchoi (Brassica chinensis L.) were significantly higher in PSB application treatments compared to the corresponding CM application treatments. Soil phosphatase, invertase and urease contents were increased most significantly in PSB treatment, 1.18-, 1.31- and 2.32-fold higher than those in the control, respectively. Soil Ca₂-P, Ca₈-P, Fe-P and Al-P concentrations exhibited the greatest increases in PSB?+?TCP treatment, while occluded-P showed minor changes in different treatments. Application of PSB fertilizer reduced the transformation of Olsen-P to Ca₁₀-P, thus increasing P availability in reclaimed soil of coal mining subsidence area.