Effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee

The effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee were examined in the laboratory. Exposed to 45 different combinations of temperature (10–30 °C) and salinity (0–40) under saturating irradiance, G. instriatum exhibited its maximum growth rate of 0.7 divisions/day at a combination of 25 °C and a salinity of 30. Optimum growth rates (>0.5 divisions/day) were observed at temperatures ranging from 20 to 30 °C and at salinities from 10 to 35. The organism could not grow at ≤10 °C. In addition, G. instriatum burst at a salinity of 0 at all temperatures, but grew at a salinity of 5 at temperatures between 20 and 25 °C. It is noteworthy that G. instriatum is a euryhaline organism that can live under extremely low salinity. Factorial analysis revealed that the contributions of temperature and salinity to its growth of the organism were almost equal. The irradiance at the light compensation point (I₀) was 10.6 μmol/(m² s) and the saturated irradiance for growth (I_s) was 70 μmol/(m² s), which was lower than I_s for several other harmful dinoflagellates (90–110 μmol/(m² s)).     

Genetic variations in the chloroplast genome and phylogenetic clustering of Lycoris species

The genus Lycoris of Amaryllidaceae comprises approximately 20 species that are distributed only in the moist warm temperate woodlands of eastern Asia. The objectives of this study were: (1) to clarify the phylogeny of the Lycoris species by using the definitive DNA sequencing method and (2) to examine the possible maternal donor of the hybrid origin Lycoris species and the Japanese triploid strains of Lycoris radiata var. radiata. The nucleotide sequence of the maturase K (matK) gene and the noncoding intergenic spacer (IGS) between the atpB and rbcL genes in the chloroplast genome were determined in a total of 27 strains of 11 species of the genus Lycoris. Variation among taxa was mainly due to nucleotide substitution, although deletions and an insertion were found in the IGS. For two chloroplast regions, the phylogenetic trees showed essentially similar topology, indicating the existence of four clades, I, II, III, and IV. For all the species except L. radiata, intraspecific variation was smaller than interspecific variation. For L. radiata, triploid strains were divided into clades I and II, and diploid strains were divided into clades I and IV. This implies that the diploid species of L. radiata var. pumila is a probable ancestral species. The clustering indicated that the chloroplast genome has not evolved in parallel with the karyotype in genus Lycoris. Regarding the hybrid origin species, the maternal parents of L. squamigara, L. albiflora and L. rosea were revealed to be L. longituba, L. radiata and L. radiata var pumila, respectively. We also suggest that a diploid strain of L. radiata var. pumila in clade I might be a candidate of the maternal donor of the Japanese triploid strains. A possible model of the maternal donor of Lycoris species is proposed.     

Peroxisomal ABC transporters: Structure, function and role in disease

ATP-binding cassette (ABC) transporters belong to one of the largest families of membrane proteins, and are present in almost all living organisms from eubacteria to mammals. They exist on plasma membranes and intracellular compartments such as the mitochondria, peroxisomes, endoplasmic reticulum, Golgi apparatus and lysosomes, and mediate the active transport of a wide variety of substrates in a variety of different cellular processes. These include the transport of amino acids, polysaccharides, peptides, lipids and xenobiotics, including drugs and toxins. Three ABC transporters belonging to subfamily D have been identified in mammalian peroxisomes. The ABC transporters are half-size and assemble mostly as a homodimer after posttranslational transport to peroxisomal membranes. ABCD1/ALDP and ABCD2/ALDRP are suggested to be involved in the transport of very long chain acyl-CoA with differences in substrate specificity, and ABCD3/PMP70 is involved in the transport of long and branched chain acyl-CoA. ABCD1 is known to be responsible for X-linked adrenoleukodystrophy (X-ALD), an inborn error of peroxisomal β-oxidation of very long chain fatty acids. Here, we summarize recent advances and important points in our advancing understanding of how these ABC transporters target and assemble to peroxisomal membranes and perform their functions in physiological and pathological processes, including the neurodegenerative disease, X-ALD. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of Peroxisomes in Health and Disease.     

Lipopolysaccharide-induced Overproduction of Nitric Oxide and Overexpression of iNOS and Interleukin-1β Proteins in Zinc-deficient Rats

Zinc deficiency leads to decreased cellular immune responses. The overproduction of nitrogen species derived from inducible nitric oxide synthase (iNOS), its enzyme, and interleukine-1 beta (IL-1β), and inflammatory cytokine have been implicated in immune responses. The goal of this study was to investigate the effects of lipopolysaccharide (LPS)-induced changes in NO metabolites, iNOS, and IL-1β protein expression in the lungs of zinc-deficient rats. Male Sprague–Dawley rats (body weight, 100 g) were divided into two groups and were fed either a zinc-deficient diet (ZnD) or a zinc-containing diet (Cont). After 4 weeks on these diets, rats received a 10-mg/kg dose of LPS injected via the tail vein and were then maintained for an additional 72 h. To determine total NO concentrations in the blood, serum zinc concentration, iNOS protein expression, IL-1β, and iNOS immunohistochemistry, blood and lung samples were obtained at pre-LPS injection, 5, 24, and 72 h after injection. Total NO levels were significantly increased at 5, at 24, and at 72 h after LPS injection compared with pre-LPS injection level in ZnD group; significant changes in total NO levels was elevated at 5 h from at pre-LPS level but not significant changes from basal level at 24 and 72 h in the control group. Based on western blot analyses and immunohistochemistry, clear bands indicating iNOS and IL-1β protein expression and iNOS antibody-stained inflammatory cells were detected at 5 and 24 h in the ZnD group and 5 h in the Cont group, not observed at 24 and 72 h in the control group. These results suggest that zinc deficiency induces overexpression of iNOS and IL-1β proteins from inflammatory cells around the alveolar blood vessels, resulting in overproduction of total NO and persisted inflammatory response in the zinc-deficient rat lung. Taken together, overexpression of LPS-induced iNOS, overproduction of iNOS-derived NO, and overexpression of IL-1β may induce nitrosative and oxidative stresses in the lung, and these stresses may be involved low immunity of zinc deficiency states.     

Excessive Zinc Intake Increases Systemic Blood Pressure and Reduces Renal Blood Flow via Kidney Angiotensin II in Rats

This study investigated the effects of excess zinc intake on the mean arterial pressure (MAP), renal blood flow (RBF), inulin clearance (IC), serum zinc level, serum angiotensin-converting enzyme (ACE) activity, and kidney angiotensin II (AT II) levels in rats. Experiments were performed on male Sprague?CDawley rats maintained for 4?weeks on a diet containing either 5?mg/100?g (control group), 50?mg/100?g (Zn50 group), or 200?mg/100?g (Zn200 group) zinc carbonate. Serum zinc levels significantly increased to 126.5?% in the Zn50 group and 198.1?% in the Zn200 group compared with controls. MAP significantly increased to 107.8?% in the Zn50 group and 114.5?% in the Zn200 group again compared with controls. Although the difference in serum ACE activity was independent of the serum zinc levels, the kidney AT II levels increased significantly to 137.2?% in the Zn50 group and 174.4?% in the Zn200 group compared with the controls. RBF was decreased significantly to 74.4?% in the Zn50 group and 69.7?% in the Zn200 group compared with the controls. IC values were significantly decreased to 69.6?% in the Zn50 group and 52.7?% in the Zn200 group as compared with control levels. Combined together, these results show that excessive Zn intake reduced IC and RBF and increased MAP and kidney AT II levels, suggesting that excessive Zn intake reduces renal function.     

Benzyl alcohol inhibits <Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="SmallCaps">d</Emphasis>-aspartate receptor-mediated neurotoxicity and calcium accumulation in cultured rat cortical neurons

The purpose of this study is to examine whether benzyl alcohol affects N-methyl-D-aspartate (NMDA) receptor in cortical cells. Benzyl alcohol (0.5–2 mM) inhibited NMDA-induced cytotoxicity. The protective effect of benzyl alcohol on NMDA-induced toxicity disappeared by washing cells with buffer to remove benzyl alcohol. Benzyl alcohol reduced NMDA receptor-mediated calcium accumulation, indicating that benzyl alcohol inhibits NMDA receptor activity.     

Identification and characterization of ten polymorphic microsatellite loci in the red panda Ailurus fulgens

Ten polymorphic microsatellite loci were characterized from two genomic DNA-enriched libraries of the red panda (Ailurus fulgens). The number of observed alleles among 35 samples of red pandas ranged from five to 12. Observed and expected heterozygosities were 0.286–0.971 and 0.443–0.894, and the mean polymorphic information content was 0.712. All loci followed Hardy–Weinberg expectations except Aifu-14 and Aifu-16, which may due to the presence of inbreeding or null alleles. Three pairs of loci exhibited significant linkage disequilibrium after Bonferroni correction for multiple comparisons. These microsatellites would be useful to strengthen population management, genetic diversity exploration, and demographic history speculation of this species.     

Alterations in manganese, copper, and zinc contents, and intracellular status of the metal-containing superoxide dismutase in human mesothelioma cells

BACKGROUND AND AIM: Molecular diagnostics and therapeutics of human mesothelioma using disease-related markers present major challenges in clinical practice. To identify biochemical alternations that would be markers of human mesothelioma, we measured the intracellular steady-state levels of biologically important trace metals such as manganese (Mn), copper (Cu), and zinc (Zn) in a human mesothelial cell line, MeT-5A, and in five human mesothelioma cell lines (MSTO-211H, NCI-H226, NCI-H2052, NCI-H2452, ACC-MESO-1) by inductively coupled plasma-mass spectrometry (ICP-MS). We also aimed to investigate whether the alterations were related to the intracellular status of metal-containing superoxide dismutase (SOD). RESULTS: There were no significant differences in the contents of the trace metals among MeT-5A, MSTO-211H, and ACC-MESO-1 cells. However, each of the other three mesothelioma cell lines had a unique characteristic in terms of the intracellular amounts of the metals; NCI-H226 contained an extremely high level of Mn, an amount 7.3-fold higher than that in MeT-5A. NCI-H2052 had significantly higher amounts of Cu (3.4-fold) and Zn (1.3-fold) compared with MeT-5A. NCI-H2452 contained about 5.8-fold the amount of Cu and 2.5-fold that of Mn compared with MeT-5A. As for the intracellular levels of copper/zinc-SOD (Cu/Zn-SOD) and manganese-SOD (Mn-SOD), those of Cu/Zn-SOD were relatively unchanged among the cells tested, and no notable correlation with Cu or Zn contents was observed. On the other hand, all mesothelioma cells highly expressed Mn-SOD compared with MeT-5A, and a very high expression of the enzyme with a robust activity was observed in the two mesothelioma cells (NCI-H226, NCI-H2452) containing a large amount of Mn. CONCLUSIONS: In comparison with MeT-5A human mesothelial cells, some human mesothelioma cells had significantly higher amounts of Mn or Cu and one mesothelioma cell had a significantly higher amount of Zn. Interestingly, all mesothelioma cells overexpressed Mn-SOD compared with MeT-5A, and the cells whose Mn-SOD activity was increased contained higher amounts of Mn. It seemed that intracellular Mn content was positively correlated with Mn-SOD, suggesting that the intracellular Mn level is associated with Mn-SOD activity. These biochemical signatures could be potential disease-related markers of mesothelioma.