Production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid from α-linolenic acid by permeabilized cells of recombinant Escherichia coli expressing the oleate hydratase gene of Stenotrophomonas maltophilia

Recombinant Escherichia coli, expressing the oleate hydratase gene of Stenotrophomonas maltophilia, was permeabilized by sequential treatments with 0.125 M NaCl and 2 mM EDTA. The optimal conditions for the production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid from α-linolenic acid by permeabilized cells were 35 °C and pH 7.0 with 0.1 % (v/v) Tween 40, 50 g permeabilized cells l^?1, and 17.5 g α-linolenic acid l^?1. Under these conditions, permeabilized cells produced 14.3 g 10-hydroxy-12,15(Z,Z)-octadecadienoic acid l^?1 after 18 h, with a conversion yield of 82 % (g/g) and a volumetric productivity of 0.79 g l^?1 h^?1. These values were 17 and 168 % higher than those obtained by nonpermeabilized cells, respectively. The concentration, yield, and productivity of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid obtained by permeabilized cells are the highest reported thus far.     

Spotted fever group rickettsia closely related to Rickettsia monacensis isolated from ticks in South Jeolla province,Korea

Rickettsia monacensis, a spotted fever group rickettsia, was isolated from Ixodes nipponensis ticks collected from live‐captured small mammals in South Jeolla province, Korea in 2006. Homogenates of tick tissues were inoculated into L929 and Vero cell monolayers using shell vial assays. After several passages, Giemsa staining revealed rickettsia‐like organisms in the inoculated Vero cells, but not the L929 cells. Sequencing analysis revealed that the ompA‐small part (25–614 bp region), ompA‐large part (2849–4455 bp region), nearly full‐length ompB (58–4889 bp region) and gltA (196–1236 bp region) of the isolates had similarities of 100%, 99.8%, 99.3% and 99.5%, respectively, to those of R. monacensis. Furthermore, phylogenetic analysis showed that the isolate was grouped into the cluster in the same way as R. monacensis in the trees of all genes examined. These results strongly suggest that the isolate is closely related to R. monacensis. As far as is known, this is the first report of isolation of R. monacensis from ticks in Korea.     

Mesozooplankton distribution patterns and grazing impacts of copepods and Euphausia crystallorophias in the Amundsen Sea, West Antarctica, during austral summer

The rapid melting of glaciers as well as the loss of sea ice in the Amundsen Sea makes it an ideal environmental setting for the investigation of the impacts of climate change in the Antarctic on the distribution and production of mesozooplankton. We examined the latitudinal distribution of mesozooplankton and their grazing impacts on phytoplankton in the Amundsen Sea during the early austral summer from December 27, 2010 to January 13, 2011. Mesozooplankton followed a latitudinal distribution in relation to hydrographic and environmental features, with copepods dominating in the oceanic area and euphausiids dominating in the polynya. Greater Euphausia crystallorophias biomass in the polynya was associated with lower salinity and higher food concentration (chlorophyll a, choanoflagellates, and heterotrophic dinoflagellates). The grazing impact of three copepods (Rhincalanus gigas, Calanoides acutus, and Metridia gerlachei) on phytoplankton was low, with the consumption of 3 % of phytoplankton standing stock and about 4 % of daily primary production. Estimated daily carbon rations for each of the three copepods were also relatively low (<10 %), barely enough to cover metabolic demands. This suggests that copepods may rely on food other than phytoplankton and that much of the primary production is channeled through microzooplankton. Daily carbon rations for E. crystallorophias were high (up to 49 %) with the grazing impact accounting for 17 % of the phytoplankton biomass and 84 % of primary production. The presence of E. crystallorophias appears to be a critical factor regulating phytoplankton blooms and determining the fate of fixed carbon in the coastal polynyas of the Amundsen Sea.     

Effect of hypo-osmotic environmental changes on the expression of gonadotropin-releasing hormone,its receptor,and gonadotropin hormone subunit mRNA in adult chum salmon (Oncorhynchus keta)

Migrating fish such as salmonids are affected by external environmental factors and salinity changes are particularly important, influencing spawning migration. The aim of this study was to test whether changes in salinity would affect the expression of the hypothalamic-pituitary-gonadal (HPG) axis hormones (gonadotropin-releasing hormones (GnRHs) [salmon GnRH and chicken GnRH-II], GnRH receptors [GnRHR1 and GnRHR5], and mRNA of the gonadotropin hormone [GTH] subunits [GTHα, follicle stimulating hormone β, and luteinizing hormone β]) in chum salmon (Oncorhynchus keta). Fish were progressively transferred from seawater (SW) through 50% SW to freshwater (FW), and the relationship between the osmoregulatory hormone prolactin (PRL) and sexual maturation was determined. The expression and activity of HPG hormones and their receptors, and levels of estradiol-17β and PRL increased after fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis and PRL production in migrating chum salmon. These findings reveal details about the role of the endocrine system in maintaining homeostasis and stimulating sexual maturation and reproduction in response to salinity changes in this species.     

Diurnal and circadian regulations by three melatonin receptors in the brain and retina of olive flounder Paralichthys olivaceus: profiles following exogenous melatonin

To establish the molecular basis of circadian rhythm control by melatonin receptors (MTs), we investigated the mitochondrial ribonucleic acid (mRNA) expressions of three types of MTs in different tissues of the olive flounder (Paralichthys olivaceus). All three types of MT mRNAs were expressed in the neural tissues, while MT1 mRNA was expressed in the peripheral tissues and MT2 and MT3 mRNAs were weakly expressed or undetected in these tissues. We observed increased MT mRNA expression in the neural tissues at night under both light–dark (LD) and constant dark (DD) conditions. Although the melatonin-treated cultured pineal gland samples showed similar diurnal variations with high-MT mRNA expression levels at night compared to those of untreated cultured pineal gland samples, the expression levels were considerably higher in the melatonin-treated samples. The plasma melatonin level also significantly increased at night. Under DD conditions, the expression patterns of MT mRNAs were similar to those under the LD photocycle, but the peak was lower and the circadian change patterns were less clear. These findings reinforce the hypothesis that MTs are active in processing light information, and that these genes are regulated by the circadian clock and light, thus suggesting that MTs play an important role in daily and circadian variations in the brain and retina of olive flounders.     

Autophagy-Related Proteins Are Required for Degradation of Peroxisomes in Arabidopsis Hypocotyls during Seedling Growth

Plant peroxisomes play a pivotal role during postgerminative growth by breaking down fatty acids to provide fixed carbons for seedlings before the onset of photosynthesis. The enzyme composition of peroxisomes changes during the transition of the seedling from a heterotrophic to an autotrophic state; however, the mechanisms for the degradation of obsolete peroxisomal proteins remain elusive. One candidate mechanism is autophagy, a bulk degradation pathway targeting cytoplasmic constituents to the lytic vacuole. We present evidence supporting the autophagy of peroxisomes in Arabidopsis thaliana hypocotyls during seedling growth. Mutants defective in autophagy appeared to accumulate excess peroxisomes in hypocotyl cells. When degradation in the vacuole was pharmacologically compromised, both autophagic bodies and peroxisomal markers were detected in the wild-type vacuole but not in that of the autophagy-incompetent mutants. On the basis of the genetic and cell biological data we obtained, we propose that autophagy is important for the maintenance of peroxisome number and cell remodeling in Arabidopsis hypocotyls.     

Photochemical Colorine Reaction of Sake

Coloring reaction of sake caused by exposure to sun-light was investigated. There is one of the coloring reactions in which deferri-ferrichrysin participate. The reaction was named Reaction I.

Deferri-ferrichrysin, tyrosine, Mn²⁺ and unknown nitrogenous compound named conveniently compound X were essential for Reaction I and citric acid was stimulative.

Compound X was purified by using Amberlite IR 120 (H type) column, active carbon column, silicic acid column and alumina column, and crystallized from methanol-water (1 : 1).

The crystals decomposed at 288~290°C. The ultraviolet and infrared spectra of the compound X were essentially identical with those of authentic kynurenic acid.

From these results the compound X was identified as kynurenic acid.

Since kynurenic acid alone did not cause the color development and riboflavin could be substituted for kynurenic acid in Reaction I, kynurenic acid may act as photosensitizer in Reaction I.     

Métabolisme de l’Acide 2-Aminoéthylphosphonique (Ciliatine) chez le Poulet

For Podospora anserina, several studies of cellulolytic enzymes have been established, but characteristics of amylolytic enzymes are not well understood. When P. anserina grew in starch as carbon source, it accumulated glucose, nigerose, and maltose in the culture supernatant. At the same time, the fungus secreted α-glucosidase (PAG). PAG was purified from the culture supernatant, and was found to convert soluble starch to nigerose and maltose. The recombinant enzyme with C-terminal His-tag (rPAG) was produced with Pichia pastoris. Most rPAG produced under standard conditions lost its affinity for nickel-chelating resin, but the affinity was improved by the use of a buffered medium (pH 8.0) supplemented with casamino acid and a reduction of the cultivation time. rPAG suffered limited proteolysis at the same site as the original PAG. A site-directed mutagenesis study indicated that proteolysis had no effect on enzyme characteristics. A kinetic study indicated that the PAG possessed significant transglycosylation activity.     

The Effect of Riboflavin on Hypertension induced by High Salt Diet in the Rat

The effect of riboflavin on development of hypertension in rats given a high salt diet was studied. Large doses of riboflavin prevented both elevation of blood pressure and rise of cholesterol levels in the serum. The increase in liver monoamine oxidase activity of the rats fed riboflavin was confirmed.