An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.

A bacterial colony was isolated from the gut of the bean bug, Riptortus clavatus. From morphological and biochemical tests, the bacterial isolate showed the highest similarity to Staphylococcus succinus. DNA sequence of 16S rRNA gene of the bacterium supported the identification. Oral administration of penicillin G to adults of R. clavatus gave a dose-dependent mortality of adults of R. clavatus to adults along with significant decrease of the bacterial population in the gut. Similarly, three metabolites (benzylideneacetone, proline-tyrosine, and acetylated phenylalanine-glycine-valine) derived from an entomopathogenic bacterium, Xenorhabdus nematophila, also inhibited growth of the gut bacterial population and gave significant mortalities to R. clavatus. These results suggest that a gut bacterial population classified as Staphylococcus sp. is required for survival of R. clavatus and that the three bacterial metabolites had toxic effects on the bugs due to their antibacterial properties.

Ingestion of plant secondary metabolites (PSMs) presents a major challenge to mammalian herbivores. We investigated the relationship between PSM concentrations in the diet and feeding patterns in sheep fed diet containing flavone extracted from Apocynum venetum. Results showed that the flavone concentrations significantly influenced food intake by sheep. With the concentration of flavone in diet increase, sheep can regulate their intake of PSM within limits that are tolerable.

Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), are symbionts of nematodes, Steinernema carpocapsae and Heterorhabditis megidis, respectively. When the nematodes enter host insect hemocoel, the bacteria are released from the nematode intestine to insect hemocoel and cause immunosuppression, which results in septicemia. Culture broth of both bacteria had insecticidal effects when injected into hemocoel of Plutella xylostella larvae, but did not when orally administered. However, either mixture of Xn or Ptt with Bacillus thuringiensis (Bt) significantly enhanced the Bt pathogenicity against P. xylostella. The culture broth was fractionated with hexane and diethylacetate extracts. Diethylacetate extract had potent factor (s) to increase Bt pathogenicity. A compound, benzylideneacetone, identified from the diethylacetate fraction had oral toxicity against P. xylostella. This compound also showed high acaricidal effect on the two spotted spider mite, Tetranychus urticae

Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), maintain monoxenic condition within host insect cadaver by synthesizing and releasing various antibiotics. These two bacteria were cultured in tryptic soy broth during different times, which were screened in their antibacterial activities. Both bacterial culture broth had high antibacterial activities against Escherichia coli at their stationary growth phase. The potent culture broth was used to screen target plant bacterial pathogens using both inhibition zone assay and liquid culture assay. Ralstonia sp. was most susceptible, while Xanthomonas sp. was highly resistant. Pseudomonas sp. and Bacillus sp. showed hemi-susceptible. The culture broth was further fractionated into hexane and diethylether extracts. Significant antibacterial effect was found in the diethylether extract

Two entomopathogenic bacteria, Xenorhadus nematophila and Photorhabdus temperata temperata, are known to suppress immune responses of target insects by inhibiting eicosanoid biosynthesis. This study analyzed these bacterial metabolites in their effects on hemocyte-spreading behavior of the beet armyworm, Spodoptera exigua. Both bacterial culture broth significantly inhibited the hemocyte-spreading behavior, at which the culture broth derived from the stationary growth phase had the most potent effect. Three identified eicosanoid synthesis inhibitors (benzylideneacetone, PY and Ac-FGV) impaired the hemocyte-spreading behavior of S. xigua, at which benzylideneacetone was the most potent. These three compounds share a common chemical structure: a pentenebenzene ring. Alternation of this common structure resulted in significant loss of their inhibitory activity to the hemocyte-spreading behavior.

This study was conducted to examine the effect of fermented alcoholic feedstuff (FAF), sustained-release recombinant bovine somatotropin(rBST) on blood metabolites and carcass characteristics of Korean native cattle, Hanwoo. The experiment was carried at the Livestock Breeding Station in Kangwon-do with fourteen bulls with two groups, control and treatment. Seven bulls per each group were allocated. In control group, bulls were treated with total mixed ration(TMR) for the whole experimental periods. In treatment group, bulls were treated whith TMR+FAF+rBST for the fattening period and TMR+FAF for finishing period, respectively. The results are summarized as follows ; Blood creatinine concentration was higher in treatment group than in control group(P<0.05), while cholesterol content in blood was lower in treatment group than in control group. There were no significant differences between in control and treatment group on back-fat thickness(BFT) and rib eye area(REA), however, MS of treatment was more improved than that of control. The frequencies of yield grade A and quality grade 1 were 33 and 17% for control group and, 50 and 50% for treatment group, respectively, which imply higher appearances of grade A and grade 1 in treatment group than in control group. The auction prices(won/carcass kg) were 11,145 and 11,573 won in control and treatment group, respectively, and net gross incomes per carcass were 654,408 and 1,051,542 won in control and treatment groups, respectively, which suggest that the margin of profit between treatment and control group was 397,134 won per carcass. Overall results indicate that the favorable feeding system to produce high quality beef with high profit is TMR+FAF+rBST feeding during the fattening period and TMR+FAF feeding during the finishing period.

This study was performed to examine the effects of recombinant bovine somatotropin (rBST) and fermented alcoholic feedstuff(FAF) on blood metabolites, carcass characteristics and profitability. Sixteen Hanwoos(bulls; 8, steers; 8) with average 143㎏ of body weight were randomly assigned to bull control group(BC), steer control group(SC), bull group(BrA) treated with rBST and FAF, and steer group(SrA) treated with rBST and FAF. Sustained release rBST(0.03㎎/㎏/body weight) was administered biweekly and dose of rBST was adjusted monthly according to body weight increase. The blood glucose content was higher in the groups treated with rBST and FAF than control groups. The blood cholesterol contents tended to be lower in the treatment groups (BrA, 120.5 mg/dl; SrA, 104.0 mg/dl) than in the control groups (BC, 141.0 mg/dl; SC, 125.5 mg/dl). No significant difference between the groups of bulls and steers were found in the blood triglyceride concentrations as well as the albumin contents. The rib eye area of BC and BrA were 70 and 72 cm2, respectively, which are slightly larger than the area of SC and SrA. The treatment did not affect the backfat thickness both in bulls and steers. The marbling scores of BC and BrA appeared as No. 1 and No. 2, respectively, and No. 3 and No. 4 were obtained in SC and SrA. Lower non saturate fat concentrations were observed in the treatment groups (BrA, 64.30%; SrA, 59.59) than in control groups (BC, 58.98%; SC, 58.09%). Saturated fatty acids and amino acids contents were slightly more improved in the treatment than in the control. Average auction prices of BC and BrA were 7,900 and 8,089 wons per 1kg of carcass, respectively, whereas the prices of SC and SrA were 9407 and 9866 wons per 1kg of carcass, respectively. It is concluded that the treatment with rBST and FAF can improve the growth performance such as marbling scores and rib eye area and increase the auction prices.

Methidathion을 흰쥐에 경구투여 및 피부도포 후 뇨 중 대사물질을 GC/MS로 분석하였고, 투여경로에 따른 뇨 중 대사물질의 차이를 비교하였으며, 뇨 중 dialkyl phosphate의 시간별 배설량과 그 외 대사물질을 측정하여 다음과 같은 결과를 얻었다. Methidathion을 경구 투여 및 피부도포 후 뇨 중 대사물질을 측정한 결과 유기인계 농약의 공통적이 대사물질인 dialkyl phosphates 중 세 가지 물질인 DMP, DMTP 및 DMDTP로 동일하게 배설되었다. GC/MS로 주요조간이온을 확인한 결과 DMP는 m/z=153,127, 109, DMTP는 m/z=198, 169, 142, 109 그리고, DMDTP는 m/z=158, 125, 93에서 분자이온을 확인할 수 있었다. Methidathion을 경구투여 및 피부도포 후 뇨 중 dialkyl phosphates의 시간별 배설량을 측정한 결과 경구투여의 경우 DMP는 12시간 이내에 79.2%, DMTP는 24시간 이내에 93.3% 그리고, DMDTP는 12시간 이내에 83.0%가 배설되었고, 피부도포의 경우 DMP는 24시간 이내에 71.1%, DMTP와 DMDTP는 48시간 이내에 각각 82.8%, 87.7%가 배설되었다. 이 결과 경구투여 한 실험에서는 48시간 이내에 뇨 중 dialkyl phosphates가 완전히 배설되는 반면 피부도포 한 실험에서는 각 개체의 상태에 따라 대사물질들이 늦게는 168시간까지 배설이 지연됨을 알 수 있었다. 이상의 결과를 종합하면, 흰쥐에 methidathion을 경구투여 및 피부도포 후 뇨 중 대사물질을 측정한 결과 dialkyl phosphate 중 DMP, DMTP 및 DMDTP로 검출되었으며, 경구투여와 피부도포 시 뇨 중 etkanfwlf의 차이는 없었으나, 경구투여보다 피부도포의 경우 배설이 더 지연되었다. 결론적으로, methidathion의 뇨 중 대사물질인 DMP, DMTP 및 DMDTP는 이 농약의 생체모니터링 지표물질로서 사용될 수 있을 것으로 생각된다.