Optimum Dietary Protein Level and Protein‐to‐energy Ratio for Growth of Juvenile Parrot Fish,Oplegnathus fasciatus

An 8‐wk feeding trial was conducted to estimate the optimum dietary protein level and protein‐to‐energy (P/E) ratio in juvenile parrot fish, Oplegnathus fasciatus. Eight experimental diets were formulated with two energy levels and four protein levels for each energy level. Diets containing crude protein (CP) at 35, 40, 45, and 50% had either 12.5 or 14.6 kJ/g of energy. Fish averaging 7.1 ± 0.06 g (mean ± SD) were fed one of the experimental diets for 8 wk. At the end of the feeding trial, weight gain (WG) of fish fed 45 and 50% CP in the 12.5 kJ/g diet was significantly higher than fish fed the 35% CP diet (P < 0.05). WG of the fish fed 45 and 50% CP in the 14.6 kJ/g diet was significantly higher than fish fed the 35 and 40% CP diets (P < 0.05). Fish fed the 14.6 kJ/g diet had a higher WG compared with fish fed the 12.5 kJ/g diet at all CP levels. Feed efficiency (FE) and specific growth rate (SGR) showed a similar trend to the WG. WG, FE, and SGR improved with increasing dietary protein levels up to 45% and remained constant at 50% CP for both energy levels. However, protein efficiency ratio was negatively related to dietary protein levels. The results suggested that the optimum level of protein and the optimum P/E ratio for juvenile parrot fish should be 45% and 31.1 mg protein/kJ, respectively, in a diet containing 14.6 kJ/g energy.     

Permeability and meniscus phenomenon in four Korean softwood species

1 Introduction A number of studies have been carried out to examine the process of liquid impregnation into different kinds of wood (Stamm and Raleigh, 1967; Bolton and Petty, 1978; Olsson et al., 2001). Different techniques and methods have been developed so far to obtain quanti- tative and qualitative information about this process (Stamm, 1953; Stone, 1956; Rudman, 1965). Penetra- tion of liquid in wood depends on several factors. The penetration rate and amount varies in different spec…     

Isolation and antifungal activity of lignans from Myristica fragrans against various plant pathogenic fungi

BACKGROUND: In a search for plant extracts with potent in vivo antifungal activity against various plant diseases, we found that treatment with a methanol extract of Myristica fragrans Houttyn (nutmeg) seeds reduced the development of various plant diseases. The objectives of the present study were to isolate and determine antifungal substances from My. fragrans and to evaluate their antifungal activities. RESULTS: Three antifungal lignans were isolated from the methanol extract of My. fragrans seeds and identified as erythro-austrobailignan-6 (EA6), meso-dihydroguaiaretic acid (MDA) and nectandrin-B (NB). In vitro antimicrobial activity of the three lignans varied according to compound and target species. Alternaria alternata, Colletotrichum coccodes, C. gloeosporioides, Magnaporthe grisea, Agrobacterium tumefaciens, Acidovorax konjaci and Burkholderia glumae were relatively sensitive to the three lignans. In vivo, all three compounds effectively suppressed the development of rice blast and wheat leaf rust. In addition, EA6 and NB were highly active against the development of barley powdery mildew and tomato late blight, respectively. Both MDA and NB also moderately inhibited the development of rice sheath blight. CONCLUSION: This is the first study to demonstrate the in vitro and in vivo antifungal activities of the three lignans from My. fragrans against plant pathogenic fungi.     

Antimicrobial resistance in Salmonella enterica serovars Enteritidis and Typhimurium isolated from animals in Korea: comparison of phenotypic and genotypic resistance characterization

Fourteen and 22 each of Salmonella Enteritidis and Salmonella Typhimurium (S. Typhimurium) were isolated from animals from 1983 to 1999 in Korea and tested for their antibiotic resistance patterns, phage types and resistance gene patterns. S. Typhimurium isolates were highly resistant to streptomycin, sulfisoxazole and tetracycline, 95, 95 and 86%, respectively. The incidence of multiple antibiotic resistance (resistant to more than two drugs tested) of S. Typhimurium isolates was extremely high (100%) comparing to S. Enteritidis isolates (21%). Two of the five ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfisoxazole and tetracycline) resistant type S. Typhimurium isolates were phage type definitive type 104 (DT104).For the detection of resistance related genes in S. Enteritidis and S. Typhimurium isolates, particularly ACSSuT type S. Typhimurium, antibiotic resistance genes, cmlA/tetR, bla(PSE-1) and bla(TEM), and genus Salmonella specific gene, sipB/C, were amplified using four pairs of primers in a hot-start multiplex polymerase chain reaction (PCR). Two Korean isolates of S. Typhimurium DT104 showed bla(TEM) amplicons instead of bla(PSE-1) for the ampicillin resistance and they were susceptible to florfenicol. The multiplex PCR used in this study was useful in characterization of multiple drug resistant Salmonella isolates, especially ACSSuT type S. Typhimurium, and identification of beta-lactamase gene distribution among Salmonella isolates.     

Physicochemical responses of Pythium porphyrae (Oomycota), the causative organism of red rot disease in Porphyra to acidification

Physicochemical responses to acidification in Pythium porphyrae , the causative organism of red rot disease in Porphyra , were investigated. The acid tolerance of P. porphyrae mycelia under pH 4 (acidic condition) condition increased significantly compared with that of the mycelia under pH 8 (condition equivalent to seawater) condition. Free amino acid levels in the mycelia decreased 1.3–8.8-fold under pH 4 condition. However, some free amino acids such as the d -cysteinolic acid-like component, phosphoethanolamine, glutamic acid, aminoadipic acid and methionine increased 2.6–21.7-fold under the same condition. Proton flux on the mycelia exposed to pH 8 increased significantly compared with the mycelia exposed to pH 4. The patterns of proteins present (examined by two-dimensional polyacrylamide gel electrophoresis) differed among the pH conditions. These results suggest that P. porphyrae acquires acid tolerance and is able to adapt to the changing pH conditions. This has significant implications for the use of acidic fungicide treatment for prevention of red rot disease on Porphyra farms.     

假单胞菌中抗真菌成分对植物病原真菌准性产孢的抑制作用

我们目前正进行铜绿假单胞菌（PAFS）中抗真菌物质的纯化研究,本文考察对卵菌产孢及菌丝生长具抑制活性的部分纯化成分的特性。PAFS中的初级成分：A1,A2,A3及A6似乎包含2类抗菌组分,A1,A2及A3对子囊菌准性产孢具特异性抑制作用,导致孢子发育不完全,然而有趣的是这些成分对菌丝生长抑制作用不明显。相反,A6对卵菌菌丝生长具抑制活性,另外在含A6条件下产生的孢子萌发的非对称性说明其抗菌活性具有持效性。     

Quantification of polyphenolics and their antioxidant capacity in fresh plums

Total phenolics, total flavonoids, and antioxidant capacity of 11 cultivars of fresh plums were determined using spectrophotometric methods. Identification and quantification of individual polyphenolics were performed using reversed-phase high-performance liquid chromatography equipped with a diode array detector. The total phenolic contents of various cultivars widely varied from 125.0 to 372.6 mg/100 g expressed as gallic acid equivalents. The level of total flavonoids in fresh plums ranged between 64.8 and 257.5 mg/100 g expressed as catechin equivalents. Antioxidant capacity, expressed as vitamin C equivalent antioxidant capacity (VCEAC), ranged from 204.9 to 567.0 mg/100 g with an average of 290.9 mg/100 g of fresh weight. Cv. Beltsville Elite B70197 showed the highest amounts of total phenolics and total flavonoids and the highest VCEAC. A positive relationship (correlation coefficient r (2)() = 0.977) was presented between total phenolics and VCEAC, suggesting polyphenolics would play an important role in free radical scavenging. The level of IC(50) value of superoxide radical anion scavenging activity of the plum cultivars ranged from 13.4 to 45.7 mg of VCEAC/100 g. Neochlorogenic acid was the predominant polyphenolic among fresh plums tested. Flavonols found in plum were commonly quercetin derivatives. Rutin was the most predominant flavonol in plums. Various anthocyanins containing cyanidin aglycon and peonidin aglycon were commonly found in all plums except for cv. Mirabellier and NY 101.     

Changes of enzyme activity and hematopoiesis in Chinese prawn Fenneropenaeus chinensis (Osbeck) induced by white spot syndrome virus and zymosan A

White spot syndrome virus and zymosan A were used to stimulate the Chinese prawn Fenneropenaeus chinensis (Osbeck), and enzyme activities in organs involved in immune defence e.g., lymphoid organ, hepatopancreas and gill, total haemocyte count and mitotic index of haematopoietic tissue (HPT) were measured. The results showed that activities of phenoloxidase (PO), superoxide dismutase (SOD), alkaline phosphatase (ALP) and acid phosphatase (ACP) were higher in lymphoid organ than in gill. The hepatopancreas had no PO activity, its SOD activity was similar to the lymphoid organ, and its ALP and ACP activities were higher than lymphoid organ and gill. Phenoloxidase activity in lymphoid organ was higher than that of the control group at 2 h after injection and lower than control after 24 h. Superoxide dismutase activity in all organs showed an increase. Alkaline phosphatase activity in lymphoid organ and gill was higher than that of the control group at 2 and 24 h after injection respectively. The difference in ACP activity was not significant. After injection with zymosan A, the mitotic index of HPT increased by 1.5‐fold compared with the control, and returned to control level after 48 h.