Photo-induced living cationic polymerization of isobutyl vinyl ether in the presence of various combinations of halides of diphenyliodonium and zinc salts in methylene chloride     

Soonhong?Kwon  Hyunjeong?Chun  Soukil?MahEmail author 《Fibers and Polymers》2004,5(4):253-258

Living nature of photoinduced cationic polymerization of isobutyl vinyl ether (IBVE) in the presence of various combinations of diphenyliodonium halide (DPIX), a photocationic initiator and zinc halide (ZnX₂) in methylene chloride has been investigated. Attainment of 100 % conversion and a linear relationship between % conversion and number average molar mass of the resulting polymer, strongly suggests the living nature of this system. Livingness of the polymerization system was observed irrespective to the type of halide anion of the initiator and zinc salts unless the reaction temperature is not higher than −30°C. The rate of polymerization decreases in the order of iodide > bromide > chloride when halide salt of DPIX and ZnX₂ are used. It is postulated that the cationic initiation is started by the insertion of weakly basic monomer in to the activated C-X terminal of the monomer adduct which is a reaction product of monomer and HX, a photolytic product of DPIX, formed in situ during the photo-irradiation process. It was concluded that polymerization is initiated by the insertion of weakly basic monomer into activated C-X terminal of monomer adduct due to the pulling action of ZnX₂, which successively producing a new polarized C-X terminal for the propagation in cationic nature. This led us to a conclusion that the living nature of this cationic polymerization is ascribable to the polarized C-X growing terminal, which is stable enough to depress the processes of chain transfer or termination process.  相似文献   

Changes in crustacean hyperglycemic hormones in Pacific whiteleg shrimp Litopenaeus vannamei subjected to air-exposure and low-salinity stresses     

Junpei Shinji  Bong Jung Kang  Tomoyuki Okutsu  Kota Banzai  Tsuyoshi Ohira  Naoaki Tsutsui  Marcy N. Wilder 《Fisheries Science》2012,78(4):833-840

Changes in crustacean hyperglycemic hormone (CHH)-family peptides in response to stress were investigated in Litopenaeus vannamei. Stress treatments consisted of air exposure and low salinity. High-performance liquid chromatography was used to quantify CHH-family peptides in the X-organ?Csinus gland complex (XO?CSG) in the eyestalks. Among the CHH-family peptides analyzed, only the level of sinus gland peptide-G (SGP-G) in the XO?CSG was decreased. SGP-G was also detectable by Western blotting analysis in the hemolymph of animals subjected to stress. These results suggest that SGP-G was secreted from the XO?CSG into the hemolymph during stress. Glucose levels in the hemolymph increased under conditions during which SGP-G was detected in the hemolymph. Hyperglycemia was also observed when SGP-G was injected. SGP-G may function to shift energy use to deal with stress.  相似文献   

Molecular cloning and characterization of <Emphasis Type="Italic">Dmc1</Emphasis>, a gene involved in gametogenesis,from the whiteleg shrimp <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>     

Tomoyuki Okutsu  Bong Jung Kang  Misako Miwa  Goro Yoshizaki  Yukio Maeno  Marcy N. Wilder 《Fisheries Science》2010,76(6):961-969

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Comparison of white spot syndrome virus quantification of fleshy shrimp Fenneropenaeus chinensis in outdoor ponds between different growing seasons by TaqMan real‐time polymerase chain reaction     

In Kwon Jang  Jong‐Sheek Kim  Bong‐Rae Kim  Xian‐Hong Meng 《Aquaculture Research》2011,42(12):1869-1877

In the present study, we used TaqMan real‐time polymerase chain reaction to quantify and compare infection of white spot syndrome virus (WSSV) with shrimp production of Fenneropenaeus chinensis cultured in outdoor ponds along the west coast of the South Korea. In 2007, a total of 60 specimens in summer and 116 specimens in autumn were collected from 12 growing‐out ponds and 12 harvest ponds respectively. Pond harvest data were obtained from farmers. Of the summer samples, all specimens were WSSV positive, with a wide range of 12.4–7.0 × 10⁷ (mean 7.5 × 10⁶) copies ng^?1 DNA; shrimp production was 1.7 metric tonnes per hectare (mt ha^?1). Of the 116 autumn‐sample specimens, 81 (69.8%) were WSSV positive; WSSV infection had been decreased dramatically, to 0–7.2 (mean 3.5) copies ng^?1 DNA. Shrimp production of autumn ponds was 2.1 mt ha^?1. Statistical analysis indicated that the difference in WSSV infections detected in summer and autumn was highly significant (P<0.01). In summer, seven ponds (58.3%) with low‐WSSV infection loads (0–1000 WSSV copies ng^?1 DNA) had shrimp production of 2.7 mt ha^?1; the others had shrimp production of only 0.2 mt ha^?1. The mean shrimp production between the two infection levels showed a highly statistically significant difference (P<0.01).  相似文献   

Alterations of pattern in immune response and vitellogenesis during induced ovarian development by unilateral and bilateral ablation in Litopenaeus vannamei     

Sun-Hye Bae  Tomoyuki Okutsu  Bong Jung Kang  Marcy N. Wilder 《Fisheries Science》2013,79(6):895-903

Eyestalk ablation is often used to induce ovarian development in female shrimp, but it possibly alters the animal’s hormonal balance, and affects its physiology and immune system. Therefore, this study was conducted to investigate alterations to the immune response during induced ovarian development by unilateral and bilateral ablation in Litopenaeus vannamei. Sub-adult female shrimp could be induced to undergo ovarian development over a 20-day period by both unilateral and bilateral eyestalk ablation; however, ovaries did not reach the final mature stage in which cortical rods are observed. In terms of immune response, total hemocyte count decreased significantly at 4 h after unilateral ablation, and at 20 days after bilateral ablation. After 20 days, expression in the hemocytes of the immune-related genes prophenoloxidase and peroxinectin in bilaterally ablated shrimp increased significantly, whereas that for penaeidin, for lipopolysaccharide- and β-glucan-binding protein, and for transglutaminase mRNA expression did not change significantly. The results of this study suggest that, while eyestalk ablation induces ovarian development, it may also bring about a hormonal imbalance that leads to immune-related genes being activated.  相似文献   

Semiparametric Kernel-Based Regression for Evaluating Interaction Between Pathway Effect and Covariate     

Zaili Fang  Inyoung Kim  Jeesun Jung 《Journal of Agricultural, Biological & Environmental Statistics》2018,23(1):129-152

Pathway-based analysis has the ability to detect subtle changes in response variables that could be missed when using gene-based analysis. Since genes interact with other covariates such as environmental or clinical variables, so do pathways, which are sets of genes that serve particular cellular or physiological functions. However, since pathways are sets of genes and since environmental or clinical variables do not have parametric relationships with response variables, it is difficult to model unknown interaction terms between high-dimensional variables and low-dimensional variables as environmental or clinical variables. In this paper, we propose a semiparametric interaction model for two unknown functions to evaluate the interaction between a pathway and environmental or clinical variable: for the pathway, we use an unknown high-dimensional function, and for environmental or clinical variable, we use an unknown low-dimensional function. We model the environmental or clinical variable nonparametrically via a natural cubic spline. We model both the pathway effect and the interaction between the pathway and environmental or clinical effect nonparametrically via a kernel machine. Since both interactions among genes within the same pathway and the interaction between the pathway and the environmental or clinical variables are complex, we allow for the possibility that a pathway is interacting with environmental or clinical variables and the genes within the same pathway are interacting with each other. We illustrate our approach using simulated data and genetic pathway data for type II diabetes. Supplementary materials accompanying this paper appear online.  相似文献   

The morphology,behaviour and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov.     

J. Nechwatal  J. Bakonyi  S. O. Cacciola  D. E. L. Cooke  T. Jung  Z. Á. Nagy  A. Vannini  A. M. Vettraino  C. M. Brasier 《Plant pathology》2013,62(2):355-369

Since its first isolation from Salix roots in 1972, isolates of a sexually sterile Phytophthora species have been obtained frequently from wet or riparian habitats worldwide and have also been isolated from roots of Alnus and Prunus spp. Although originally assigned to Phytophthora gonapodyides on morphological grounds, it was recognized that these isolates, informally named P. taxon Salixsoil, might represent a separate lineage within ITS Clade 6. Based on phylogenetic analyses and comparisons of morphology, growth‐temperature relationships and pathogenicity, this taxon is formally described here as Phytophthora lacustris sp. nov. Isolates of P. lacustris form a clearly resolved cluster in both ITS and mitochondrial cox1 phylogenies, basal to most other Clade 6 taxa. Phytophthora lacustris shares several unusual behavioural properties with other aquatic Clade 6 species, such as sexual sterility and tolerance of high temperatures, that have been suggested as adaptations to riparian conditions. It appears to be widespread in Europe and has also been detected in Australia, New Zealand and the USA. It was shown to be weakly or moderately aggressive on inoculation to Alnus, Prunus and Salix. The extent of P. lacustris’ activity as a saprotroph in plant debris in water and as an opportunistic pathogen in riparian habitats needs further investigation. Its pathogenic potential to cultivated fruit trees also deserves attention because P. lacustris has apparently been introduced into the nursery trade.  相似文献   

Conservation and climate change: Assessing the vulnerability of snow leopard habitat to treeline shift in the Himalaya     

Jessica L. Forrest  Eric Wikramanayake  Rinjan Shrestha  Gopala Areendran  Kinley Gyeltshen  Aishwarya Maheshwari  Sraboni Mazumdar  Robin Naidoo  Gokarna Jung Thapa  Kamal Thapa 《Biological conservation》2012,150(1):129-135

Climate change is likely to affect the persistence of large, space-requiring species through habitat shifts, loss, and fragmentation. Anthropogenic land and resource use changes related to climate change can also impact the survival of wildlife. Thus, climate change has to be integrated into biodiversity conservation plans. We developed a hybrid approach to climate-adaptive conservation landscape planning for snow leopards in the Himalayan Mountains. We first mapped current snow leopard habitat using a mechanistic approach that incorporated field-based data, and then combined it with a climate impact model using a correlative approach. For the latter, we used statistical methods to test hypotheses about climatic drivers of treeline in the Himalaya and its potential response to climate change under three IPCC greenhouse gas emissions scenarios. We then assessed how change in treeline might affect the distribution of snow leopard habitat. Results indicate that about 30% of snow leopard habitat in the Himalaya may be lost due to a shifting treeline and consequent shrinking of the alpine zone, mostly along the southern edge of the range and in river valleys. But, a considerable amount of snow leopard habitat and linkages are likely to remain resilient to climate change, and these should be secured. This is because, as the area of snow leopard habitat fragments and shrinks, threats such as livestock grazing, retaliatory killing, and medicinal plant collection can intensify. We propose this approach for landscape conservation planning for other species with extensive spatial requirements that can also be umbrella species for overall biodiversity.  相似文献   

Acaricidal toxicity of 2'-hydroxy-4'-methylacetophenone isolated from Angelicae koreana roots and structure-activity relationships of its derivatives     

Oh MS  Yang JY  Lee HS 《Journal of agricultural and food chemistry》2012,60(14):3606-3611

The acaricidal activities of 2'-hydroxy-4'-methylacetophenone derived from Angelica koreana roots and its derivatives against Dermatophagoides farinae, Dermatophagoides pteronyssinus, and Tyrophagus putrescentiae were examined by vapor phase and contact toxicity bioassays. In the vapor phase toxicity bioassay, 2'-methylacetophenone (1.25 μg/cm(2)) was 8.0 times more toxic against D. farinae than benzyl benzoate (10.00 μg/cm(2)), followed by 3'-methylacetophenone (1.26 μg/cm(2)), 4'-methylacetophenone (1.29 μg/cm(2)), 2'-hydroxy-4'-methylacetophenone (1.75 μg/cm(2)), and 2'-hydroxy-5'-methylacetophenone (1.96 μg/cm(2)). In the contact toxicity bioassay, 3'-methylacetophenone (0.58 μg/cm(2)) was 17.24 times more effective against D. farinae than benzyl benzoate (7.52 μg/cm(2)), followed by 2'-methylacetophenone (0.64 μg/cm(2)), 2'-hydroxy-4'-methylacetophenone (0.76 μg/cm(2)), 4'-methylacetophenone (0.77 μg/cm(2)), and 2'-hydroxy-5'-methylacetophenone (1.16 μg/cm(2)). The acaricidal activities of 2'-hydroxy-4'-methylacetophenone derivatives against D. pteronyssinus and T. putrescentiae were similar to those against D. farinae. In terms of structure-activity relationships, acaricidal activity against the three mite species changed with the introduction of hydroxyl and methyl functional groups onto the acetophenone skeleton. Furthermore, some of 2'-hydroxy-4'-methylacetophenone derivatives could be useful for natural acaricides against three mite species.  相似文献   

In vitro digestion rate and estimated glycemic index of oat flours from typical and high β-glucan oat lines     

Kim HJ  White PJ 《Journal of agricultural and food chemistry》2012,60(20):5237-5242

The in vitro starch digestion rate and estimated glycemic index (GI) of oat flours and oat starches from typical and high β-glucan oat lines were evaluated along with the impact of heating on starch digestion. Flour from oat lines ('Jim', 'Paul', IA95, and N979 containing 4.0, 5.3, 7.4, and 7.7% β-glucan, respectively) was digested by pepsin and porcine pancreatin. To determine the impact of heating on starch digestion, oat slurries were prepared by mixing oat flour and water (1:8 ratio) and heating for 10 min prior to digestion. Viscosity, as measured on a Rapid Visco Analyzer, increased with increases in concentration and molecular weight of β-glucan. The in vitro starch digestion of oat flours and a control, white bread made from wheat flour, increased as the digestion time increased. Starch digestion of oat flour was slower than that of the control (p < 0.05). Heat treatment of oat-flour slurries increased the starch digestion from a range of 31-39% to a range of 52-64% measured after 180 min of in vitro digestion. There were no differences in starch digestibility among oat starches extracted from the different oat lines. The GI, estimated by starch hydrolysis of oat flours, ranged from 61 to 67, which increased to a range of 77-86 after heating. Oat-flour slurries prepared from IA95 and N979 lines with high β-glucan concentrations had lower GI values than did slurries made from Jim and Paul lines. Starch digestion was negatively correlated with β-glucan concentrations in heated oat-flour slurries (R(2) = 0.92). These results illustrate that the oat soluble fiber, β-glucan, slowed the rate of starch digestion. This finding will help to develop new food products with low GI by using oat β-glucan.  相似文献