Quantitative study of PNSB energy metabolism in degrading pollutants under weak light-micro oxygen condition

Contribution and relationship between oxidative phosphorylation and photophosphorylation pathways in purple non-sulfur bacteria (PNSB) wastewater treatment under weak light-micro oxygen condition were studied quantitatively. Results showed that under weak light-anaerobic condition, PNSB followed photophosphorylation with the first-order degradation kinetic constant k₃ of 0.0585. Under dark-micro aerobic condition, it followed oxidative phosphorylation with k₂ of 0.0896. Under weak light-micro oxygen condition, both pathways existed with k₁ of 0.108. When light and oxygen both existed, oxidative phosphorylation had a strong competitiveness, it played a dominative role and counted for 92.7% in pollutants degradation, and meanwhile photophosphorylation was restrained by 81.6%. Theoretical analysis showed the common part from coenzyme Q (CoQ) to cytochrome c2 (Cyt c2) in both respiration and photosynthetic chains might cause the competition. When oxygen existed, respiration electron transport would be enhanced. Other potential explanations included that oxygen might damage the pigment and membrane system vital to photophosphorylation.     

Biochemical characterization of deblocking aminopeptidases from the hyperthermophilic archaeon Thermococcus kodakarensis KOD1

Deblocking aminopeptidase (DAP) is an exoprotease that can release N-terminal amino acids from blocked peptides. Three DAP homologous (TkDAP1, TkDAP2, and TkDAP3) are annotated in the genome data base of Thermococcus kodakarensis KOD1. TkDAP2 and TkDAP3 were identified as proteins that are overexpressed in response to heat and oxidative stress by two-dimensional electrophoresis. In this study, the TkDAP1 and TkDAP2 genes were cloned and expressed in Escherichia coli. The two proteins were purified homogeneity and analyzed by gel filtration chromatography and electron microscopy. TkDAP1 showed two oligomers, which were identified as an octodecimer and a dodecamer. TkDAP2 produced three native forms: octodecimer, dodecamer, and trimer. Dodecamer assembly was the main form in the two proteins. Finally, TkDAP1 was found to have higher deblocking aminopeptidase activity on the substrates of Ac-Leu-pNA and Ac-Ala-Ala-Ala, while TkDAP2 had higher aminopeptidase activity on the substrates of Leu-pNA and Ala-Ala-Ala-pNA.     

NaCl-induced stress: physiological responses of six halophyte species in in vitro and in vivo culture

Plant Cell, Tissue and Organ Culture (PCTOC) - To investigate the mechanisms underlying salt tolerance, physiological parameters of six halophyte species [Vitex rotundifolia L., Clerodendrum inerme...     

Characterization of the unarmored dinoflagellate Pseliodinium pirum (Ceratoperidiniaceae) from Jiaozhou Bay,China

A strain of Pseliodinium pirum was isolated from Jiaozhou Bay, China, identified based on a recently emended classification, and further characterized for its morphology using light, scanning electron, and transmission electron microscopy, and phylogeny based on SSU and partial LSU rDNA sequences. The pigment composition, life history, and potential effects on aquatic animals were also examined. We observed the typical characteristics of Ceratoperidiniaceae, in which its apical structure complex (ASC) formed a circular loop, and the ASC of our isolate comprised four to five rows of vesicles, and connected with sulcal intrusion. Epifluorescence and transmission electron microscopy revealed a bean‐shaped, centrally located nucleus, with at least 76 chromosomes. Numerous rod‐shaped chloroplasts were in connection to the irregularly shaped pyrenoids. Pigment analysis showed that peridinin was the most abundant among all carotenoids and other pigments. Phylogenetic analyses using maximum likelihood and Bayesian inference indicated that our isolate is conspecific with the entity Cochlodinium cf. helix (accession No. KF245459), but different from Ceratoperidinium, Kirithra, and other unidentified species of the family Ceratoperidiniaceae. Pseliodinium pirum could produce sexual, thin‐walled cyst, with subspherical and spherical shape and smooth surface (without spines or rough projections). The cyst could germinate within 3 days. Bioassays did not show adverse effects of P. pirum on the finfish Oryzias melastigma and the rotifer Brachionus plicatilis, indicating it may not be a harmful species.     

Mustard seeds (Sinapis Alba Linn) attenuate azoxymethane-induced colon carcinogenesis

Mustard seeds (MS), which are consumed in considerable amounts by the Japanese people that, interestingly, have the longest life expectancy in the world, are known to contain a number of yet not fully defined but quite powerful anti-oxidants. A suspension of extracted MS was found to suppress oxidized-LDL-induced macrophage respiratory burst in vitro, to prevent growth, and to induce apoptotic death of SW480 cells (a human colon cancer cell line), while no such effects were found for normal 3T3 cells. A diet enriched with MS decreased plasma levels of the lipid peroxidation product malonaldehyde in mice exposed to the colon cancer-inducer azoxymethane (AOM). Such a diet also dose-dependently enhanced the activity of several anti-oxidant enzymes, such as superoxide dismutase (SOD), catalase, and GSH-peroxidase and, moreover, reduced AOM-mediated formation of colon adenomas by about 50%. Further studies are required to detail and explore the beneficial effects of MS and their rich content of powerful anti-oxidants.     

Comparison of phenotypes between different vangl2 mutants demonstrates dominant effects of the Looptail mutation during hair cell development

Experiments utilizing the Looptail mutant mouse, which harbors a missense mutation in the vangl2 gene, have been essential for studies of planar polarity and linking the function of the core planar cell polarity proteins to other developmental signals. Originally described as having dominant phenotypic traits, the molecular interactions underlying the Looptail mutant phenotype are unclear because Vangl2 protein levels are significantly reduced or absent from mutant tissues. Here we introduce a vangl2 knockout mouse and directly compare the severity of the knockout and Looptail mutant phenotypes by intercrossing the two lines and assaying the planar polarity of inner ear hair cells. Overall the vangl2 knockout phenotype is milder than the phenotype of compound mutants carrying both the Looptail and vangl2 knockout alleles. In compound mutants a greater number of hair cells are affected and changes in the orientation of individual hair cells are greater when quantified. We further demonstrate in a heterologous cell system that the protein encoded by the Looptail mutation (Vangl2(S464N)) disrupts delivery of Vangl1 and Vangl2 proteins to the cell surface as a result of oligomer formation between Vangl1 and Vangl2(S464N), or Vangl2 and Vangl2(S464N), coupled to the intracellular retention of Vangl2(S464N). As a result, Vangl1 protein is missing from the apical cell surface of vestibular hair cells in Looptail mutants, but is retained at the apical cell surface of hair cells in vangl2 knockouts. Similarly the distribution of Prickle-like2, a putative Vangl2 interacting protein, is differentially affected in the two mutant lines. In summary, we provide evidence for a direct physical interaction between Vangl1 and Vangl2 through a combination of in vitro and in vivo approaches and propose that this interaction underlies the dominant phenotypic traits associated with the Looptail mutation.