The effect of active immunization against adrenocorticotropic hormone on cortisol, beta-endorphin, vocalization, and growth in pigs

Because the poor growth performance of intensively housed pigs is associated with increased circulating glucocorticoid concentrations, we investigated the effects of glucocorticoid suppression by inducing a humoral immune response to ACTH on physiological and production variables in growing pigs. Grower pigs (28.6 +/- 0.9 kg) were immunized with amino acids 1 through 24 of ACTH conjugated to ovalbumin and suspended in diethylaminoethyl (DEAE) dextran-adjuvant or adjuvant alone (control) on d 1, 28, and 56. The ACTH-specific antibody titers generated suppressed increases in cortisol concentrations on d 63 in response to an acute stressor (P = 0.002; control = 71 +/- 8.2 ng/mL; ACTH-immune = 43 +/- 4.9 ng/mL) without altering basal concentrations. Plasma beta-endorphin concentrations were also increased (P < 0.001) on d 63 (control = 18 +/- 2.1 ng/mL; ACTH-immune = 63 +/- 7.3 ng/mL), presumably because of a release from negative feedback on the expression of proopiomelanocortin in pituitary corticotropes. Immunization against ACTH did not alter ADG (P = 0.120; control = 1,077 +/- 25; ACTH-immune = 1,143 +/- 25 g) or ADFI (P = 0.64; control = 2,719 +/- 42; ACTH-immune = 2,749 +/- 42 g) and did not modify behavior (P = 0.681) assessed by measuring vocalization in response to acute restraint. In summary, suppression of stress-induced cortisol responses through ACTH immunization increased beta-endorphin concentrations, but it did not modify ADG, ADFI, or restraint vocalization score in growing pigs.     

Modifying Myxococcus xanthus protoporphyrinogen oxidase to plant codon usage and high level of oxyfluorfen resistance in transgenic rice

Protoporphyrinogen oxidase (Protox) of Myxococcus xanthus (Mx Protox) is a 49-kDa membrane protein that catalyzes conversion of protoporphyrinogen IX (Protogen IX) into protoporphyrin IX (Proto IX). Upon heterologous expression in transgenic rice plants, Mx Protox is dually targeted into plastids and mitochondria, increasing resistance against the herbicidal Protox inhibitor oxyfluorfen. Here, we describe the chemical synthesis of the Mx Protox gene by assembling several small synthetic DNA fragments derived by ligation-PCR. Codon usage in the resulting 1416-bp gene was modified to correspond to that of the Arabidopsis Protox gene, a change that resulted in a decrease in G+C content from 71 to 49%. The modified Mx Protox gene was used to generate transgenic rice plants via Agrobacterium-mediated transformation. Integration, expression, and inheritance of the transgenes were demonstrated by Southern, Northern, and Western blot analyses. In plants transformed with the modified, low G+C-content Mx Protox gene, levels of Protox expression and enzyme activity were low compared to the levels observed for plants transformed with the native Mx Protox gene. Nonetheless, like the native gene, the modified gene conferred a high level of resistance to the herbicide oxyfluorfen in a seedling growth test.     

First molecular genotyping of voltage gated sodium channel alleles in Culex quinquefasciatus populations in Malaysia

A nationwide investigation was performed to detect the presence of 1014 mutation(s) in voltage gated sodium channel (kdr) gene of Culex quinquefasciatus from 14 residential areas across 13 states and a federal territory in Malaysia. Molecular genotyping of kdr mutation was performed via a modified three tubes allele-specific-polymerase chain reaction (AS-PCR) and direct sequencing of kdr gene. Based on the results of AS-PCR, homozygous susceptible (SS) genotype was found in nine out of 14 populations with 38 individuals from a total sample size of 140. Heterozygous (RS) genotype was most predominant (99 individuals) and distributed across all study sites. Homozygous resistance (RR) genotype was detected in Perak (one individual) and Selangor (two individuals). The resistance kdr allele frequencies ranged from 0.1 to 0.55, with the highest being detected in Cx. quinquefasciatus population from Selangor. This study has documented the first field-evolved instance of 1014F mutation in Malaysian mosquitoes and the findings of this study could be utilized in the implementation of strategic measures in vector control programs in Malaysia.     

Evaluation of Seed Vigor Tests for Predicting Seedling Establishment at Low Temperature in Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

This study was carried out to develop an evaluation method to predict rice seedling establishment (SE) under low-temperature conditions. Two Korean-bred japonica cultivars, Shindongjin and Hopum were used in the experiment. Fresh seeds were treated with an accelerated aging (AA) at 40°C and 100% RH for 1-15 days. The SEs of the fresh and AA seeds were evaluated in nursery beds at 17°C, and their correlation coefficients with seed vigor values measured by 9 test methods including standard germination test (SGT), cool germination test (CLT), cold germination test (CDT), seedling growth rate test (SGRT), ascorbate peroxidase (APX), peroxidase (POX), superoxide dismutase (SOD), catalase (CAT), and α ‐amylase (AMY) activities. The percentage of SE decreased slowly from 75 to 0% with an increasing of AA period from 0 to 15 days. The result of nine vigor tests showed different correlations with the SE. SGT, CLT, SGRT, and POX were significantly correlated with the SE. In the correlation analysis with only short-term aging seeds (1-7 days), the SE was very highly correlated with SGT, CLT, CDT, SGRT, POX, and CAT. These results suggest that seed vigor values measured by several methods including SGT and POX could be used as a reference value to secure SE at low temperatures in nursery bed rice seedling culture.     

Three AFLP markers tightly linked to the genic male sterility <Emphasis Type="Italic">ms</Emphasis><Subscript><Emphasis Type="Italic">3</Emphasis></Subscript> gene in chili pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) and conversion to a CAPS marker

Genic male sterility (GMS) has long been used as a tool for hybrid seed production in chili pepper (Capsicum annuum L.). We developed DNA markers linked to the GMS ms ₃ gene in a segregating population using bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) techniques. The segregating population was subjected to BSA-AFLP with 512 primer combinations. Three AFLP markers (Eagg/Mccc₂₇₆, Eagc/Mctt₁₇₈, and Ecag/Mtgc₂₀₄) were identified as tightly linked to the ms ₃ locus. Among them, we converted the AFLP marker Ecag/Mtgc₂₀₄ to the cleavage amplified polymorphic sequence (CAPS) marker, named GMS3-CAPS, based on sequencing analysis of internal and flanking regions for the markers between male-fertile and sterile plants. This marker will be useful for pepper breeding using the GMS system.     

Genetic, agronomic and quality comparisons of two 1AL.1RS. wheat-rye chromosomal translocations

The 1AL.1RS wheat-rye chromosomal translocation originally found in ‘Amigo’ wheat possesses resistance genes for stem rust, powdery mildew and greenbug biotypes B and C, but also has a negative effect on wheat processing quality. Recently, a second 1AL.1RS translocation carrying Gb6, a gene conferring resistance to greenbug biotypes B, C, E, G and I, was identified in the wheat germplasm line ‘GRS1201′. Protein analytical methods, and the DNA polymerase chain reaction were used to identify markers capable of differentiating the 1RS chromosome arms derived from ‘Amigo’ and ‘GRS1201′. The secalin proteins encoded by genes on 1RS chromosome arms differed in ‘Amigo’ and ‘GRS1201′. A 70 kDa secalin was found in the ‘Amigo’1AL.1RS, but did not occur in the ‘GRS1201’1AL.1RS. Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also differentiated the two translocations. When ‘GRS1201’was mated with a non-1RS wheat, no recombinants between 1RS markers were observed. In crosses between 1RS and non-1RS parents, both DNA markers and secalins would be useful as selectable markers for 1RS-derived greenbug resistance. Recombination between 1RS markers did occur when 1RS from ‘Amigo’ and 1RS from ‘GRS1201’were combined, but in such intermatings, the molecular markers described herein could still be used to develop a population enriched in lines carrying Gb6. No differences in grain yield or grain and flour quality characteristics were observed when lines carrying 1RS from ‘Amigo’ were compared with lines with 1RS from ‘GRS1201′. Hence, differences in secalin composition did not result in differential quality effects. When compared with sister lines with 1AL.1AS derived from the wheat cultivar ‘Redland’, lines with ‘GRS1201’had equal grain yield, but produced flours with significantly shorter mix times, weaker doughs, and lower sodium dodecyl sulphate sedimentation volumes.     

Dietary eicosapentaenoic acid requirement of juvenile rock bream,Oplegnathus fasciatus

A feeding trial was conducted to evaluate the optimum dietary level of eicosapentaenoic acid (EPA, 20:5n‐3) based on growth and non‐specific immune responses in juvenile rock bream. A basal diet without EPA supplementation was used as a control, and six other diets were prepared by supplementing with 4, 8, 12, 16, 20 or 40 g of EPA per kg diet. The actual EPA concentrations of the diets were 0.5, 4.3, 8.5, 13.0, 16.8, 21.0 and 41.2 g of EPA per kg diet, and the diets were abbreviated as EPA_0.5, EPA_4.3, EPA_8.5, EPA_13.0, EPA_16.8, EPA_21.0 and EPA_41.2, respectively. Triplicate groups of fish averaging 1.06 ± 0.01 g (mean ± SD) were fed one of the seven experimental diets at the apparent satiation for 8 weeks. At the end of the feeding trial, weight gain, specific growth rate and feed efficiency of fish fed EPA_16.8, EPA_21.0 and EPA_41.2 diets were significantly higher than those of fish fed EPA_0.5, EPA_4.3, EPA_8.5 and EPA_13.0 diets (p < .05). Superoxide dismutase activity of fish fed EPA_16.8, EPA_21.0 and EPA_41.2 diets were significantly higher than those of fish fed EPA_0.5, EPA_4.3 and EPA_8.5 diets. Fish fed EPA_21.0 and EPA_41.2 diets showed significantly higher lysozyme activity than did fish fed EPA_0.5, EPA_4.3, EPA_8.5 and EPA_13.0 diets. The broken‐line analysis of weight gain indicated that the optimum dietary EPA level was 16.7 g/kg diet. These results suggested that the optimum dietary EPA level in juvenile rock bream could be greater than 16.7 g/kg diet but less than or equal to 16.8 g/kg diet based on the broken‐line analysis and the ANOVA test of weight gain.     

Output of methylmercury from a Catchment in northern Sweden

The runoff output of methylmercury (MeHg) from the 50 ha Svartberget Catchment in northern Sweden was studied during 1993. These outputs are compared to those from the Gårdsjön Catchment in the southwestern part of Sweden. Although the wet deposition of MeHg is several times higher in southern Sweden the output of MeHg per unit area from the two catchments was comparable (0.12 g /km_* ²yr). Furthermore, the concentration of MeHg (0.4 ng/L) in the Svartberget Catchment was more than twice that from the Gårdsjön Catchment. These results suggest that the contemporary wet deposition of MeHg in itself is not a good indicator of runoff concentration or output per unit area. DOC transport and catchment characteristics such as wetland area, or possibly other forms of contemporary atmospheric deposition may all be more important for explaining MeHg output from the terrestrial ecosystem.