Phenology of the rhodomelarian algae Neorhodomela aculeata and Ceramium kondoi and their survival strategies against herbivorous snails

The seasonal growth and reproductive phenology of Neorhodomela aculeata (Perestenko) Masuda and Ceramium kondoi Yendo, and the food preferences of herbivorous snails were examined to elucidate (i) why snails select the fronds of N. aculeata for their habitat; and (ii) the survival strategies of the two red algae under grazing pressures. The maximal lengths and weights of both algal species were recorded for each season over a 12‐month period beginning with the spring of 2003. C. kondoi grew in length at a faster rate than N. aculeate, whereas the turf alga N. aculeata produced new branches from the tips of broken branches. The reproductive period of C. kondoi was between the spring and summer but the reproductive organs of N. aculeata were observed throughout the year. The algal loss rate of fresh N. aculeata to snails was low but snails had a food preference for N. aculeata when compared to C. kondoi in an artificial food experiment. These results indicate that snails may adapt to chemical compounds characteristic of N. aculeata and that the alga further reduces predation damage by its structural resistance. In conclusion, the survival strategies of C. kondoi appear to be rapid growth, seasonal sexual reproduction, and a delicately branched frond morphology that reduces stable feeding patterns of its predators plus high tissue nitrogen content, whereas the survival strategy of N. aculeata includes regenerative growth responses, structural toughness and chemical defenses while under the grazing pressure of herbivorous snails.     

Production of Recombinant Hinnavin II/MSH Hybrid in Insect Cells

The increasing problem of antibiotic resistance among pathogenic bacteria requires development of new antimicrobial agents. For the purpose of this study, a cDNA encoding hinnavin II‐α‐melanocyte stimulating hormone (hin/MSH) hybrid was chemically synthesized, annealed, and then cloned into transfer vector pBacPAK 9 for expression in Sf21 insect cells. Recombinant hin/MSH (rhin/MSH) hybrid was efficiently produced in baculovirus expression vector system (BEVS) as a hybrid peptide. The antibacterial activity of the rhin/MSH hybrid was compared to that of the recombinant hinnavin II (rhin), using inhibition zone and overlay assay. This new recombinant hybrid peptide may serve as an attractive candidate for powerful novel class of antimicrobial pharmaceuticals.     

cDNA cloning and sequence analysis of the rice Cinnamate-4-Hydroxylase gene, a cytochrome P450-dependent monooxygenase involved in the general phenylpropanoid pathway

Plant cytochrome P450 monooxygenases (P450s) mediate a wide range of oxidative reactions involved in the biosynthesis of phenylpropanoids, terpenes, lipids, and alkaloids. We isolated a cDNA clone for cinnamate-4-hydroxylase (C4H) from a Japonica type rice(Oryza sativa L. cv. llpumbyeo). This C4H has a deduced amino acid sequence that is 85% identical tothat ofSorghum bicolor. Our phylogenetic analysis also showed that theOsC4HL gene is closely related toC4H fromS. bicolor. A putative genomic DNA sequence corresponding toOsC4HL contained cis-elements (boxes P, A, L, and TCA motifs), AT-rich elements, and wound-response elements that control gene expression in its promoter region.OsC4HL expression was detected in all the tissue types, with the highest level being measured in the roots. It was also apparently up-regulated by wounding stress. These data suggest that theOsC4HL gene isC4H member in theCYP73 subfamily.     

Physiological significance of hydrophilic and hydrophobic textile materials during intermittent exercise in humans under the influence of warm ambient temperature with and without wind

The purpose of this present study was to compare the physiological effects of the hydrophilic and hydrophobic properties of the fabrics investigated in exercising and resting subjects at an ambient temperature of 30°C and a relative humidity of 50% with and without wind. Three kinds of clothing ensemble were tested: wool and cotton blend with high moisture regain (A), 100% cotton with intermediate moisture regain (B), 100% polyester clothing with low moisture regain (C). The experiments were performed using seven young adult women as subjects. They comprised six repeated periods of 10-min exercise on a cycle ergometer at an intensity of 40% maximal oxygen uptake followed by 5 min of rest (20 min for the last rest). The experiments comprised two sessions. During session I (first three repetitions of exercise and rest) the subjects were exposed to an indifferent wind velocity and during session II (last three repetitions of exercise and rest) they were exposed to a wind velocity of 1.5 m · s⁻¹. Rectal temperature and skin temperatures at eight sites, pulse rate and clothing microclimate were recorded throughout the whole period. The main findings can be summarized as follows: rectal temperature during session II was kept at a significantly lower level in A than in B and C. Clothing microclimate humidity at the chest was significantly lower in A than in B and C during session II. Skin and clothing microclimate temperatures at the chest were significantly lower in A than in B and C during session II. Pulse rate was significantly higher in C than in A and B during sessions I and II. It was concluded that the hydrophilic properties of the fabrics studied were of physiological significance for reducing heat strain during exercise and rest especially when influenced by wind. Accepted: 3 June 1998     

Biological, Immunological, and Genetic Analysis of Bacillus thuringiensis Isolated from Granary in Korea

To isolate a naturally occurring novel Bacillus thuringiensis strain, we investigated the distribution, toxicity, morphology, H serotype, and gene type of B. thuringiensis from residue samples of granary in Korea. A total of 163 B. thuringiensis isolates out of 411 samples producing spore and crystal were obtained. In toxicity tests, 80% of all isolates were toxic to lepidoptera, and 12% were not toxic to any of tested insects. And dipteran-active and lepidopteran/dipteran-active isolates were rare (2% and 6%, respectively). 152 B. thuringiensis isolates produced typical rhomboidal crystals, and the remainder produced parasporal inclusions with various morphologies. Serological test showed that B. thuringiensis isolates in granary represented 12 H serotypes, indicating varied distribution of B. thuringiensis. Of these, the serotype 3ab predominated, followed by the serotype 7 and 4ac. B. thuringiensis isolates of the serotype 3ab, 4ac, 5ab, 7, 8ab, 9, and 23 were toxic to lepidoptera, and the serotype 8bd, 12, 18, and 20ac were nontoxic, while 14 isolates were untypable by 33 B. thuringiensis H antisera. The frequency of toxicity against lepidoptera and diptera was primarily highly toxic. PCR analysis using cryI gene type-specific primers showed that cryIA(b) genes are frequently found and cryIE gene exists in only one isolate. Analysis of B. thuringiensis crystals and plasmid DNAs indicated a diversity of crystal and gene types. Received: 15 January 1998 / Accepted: 18 February 1998     

Effect of <Emphasis Type="Italic">Liriomyza huidobrensis</Emphasis> (Diptera: Agromyzidae) density on foliar leaf damage and yield loss in potato

Liriomyza huidobrensis (Blanchard) is a key pest of potatoes worldwide and an emerging pest of potatoes in Korea. To understand the nature of the damage caused by this pest and the potential for yield loss, potato (Solanum tuberosum), cv. Superior was exposed to different pest infestation levels (0, 2, 5, 10, 20, and 50 individuals/cage) for 27 days and the relationship between pest density and crop damage assessment was determined using both laboratory cage studies and field cages. Leaf stippling, number of mines per leaf, % leaf area mined, and yield loss varied significantly with infestation density level in both the laboratory and field. The greatest leaf area mined and yield loss were associated with the 20- and 50-individual infestation rates in both the laboratory and field. There was a significant relationship between female choice (as shown by stippling, caused by adult feeding and oviposition) and larval performance (as reflected by the number of mines, damaged leaf area, and yield loss). It is important to understand the nature of the damage caused by L. huidobrensis and to determine its economic threshold for potato in order to optimize the management of this leafminer and minimize management costs.