Mapping QTL for fat area ratios and serum leptin concentrations in a Duroc purebred population

The reduction of extra subcutaneous, intermuscular and abdominal fat is important to increase the carcass lean percentage of pigs. Image analyses of fat area ratios were effective for estimation of separated fat in pig carcasses. Serum concentrations of leptin are useful as physiological predictors of fat accumulation in pigs. The objectives of the present study were to perform a quantitative trait locus (QTL) analysis for fat area ratios and serum leptin concentrations in a Duroc purebred population. Pigs (n = 226 to 538) were measured for fat area ratios of carcass cross‐sections at the fifth to sixth thoracic vertebrae, half body length and last thoracic vertebra using an image analysis system, and serum leptin concentration. In total, animals were genotyped for 129 markers and used for QTL analysis. For fat area ratios, four significant and 12 suggestive QTLs were detected on chromosomes 1, 6, 7, 8, 9, 12 and 13. Significant QTLs were detected on the same region of chromosome 6, which was located near a leptin receptor gene. For serum leptin concentrations, two significant and two suggestive QTLs were detected on chromosomes 6, 9, and 16, and the QTLs on chromosome 6 were also in the same region for fat area ratios.     

Common nucleotide sequence of structural gene encoding fibroblast growth factor 4 in eight cattle derived from three breeds

Fibroblast growth factor 4 (FGF4) is considered as a crucial gene for the proper development of bovine embryos. However, the complete nucleotide sequences of the structural genes encoding FGF4 in identified breeds are still unknown. In the present study, direct sequencing of PCR products derived from genomic DNA samples obtained from three Japanese Black, two Japanese Shorthorn and three Holstein cattle, revealed that the nucleotide sequences of the structural gene encoding FGF4 matched completely among these eight cattle. On the other hand, differences in the nucleotide sequences, leading to substitutions, insertions or deletions of amino acid residues were detected when compared with the already reported sequence from unidentified breeds. We cannot rule out a possibility that the structural gene elucidated in the present study is widely distributed in cattle. To the best of our knowledge, this is the first determination of the complete nucleotide sequence of the structural gene encoding bovine FGF4 in identified breeds.     

Effects of winter barley as a cover crop on the weed vegetation in a no-tillage soybean

The present study clarified the effects of winter barley as a cover crop on the weed vegetation, expressed as a multiplied dominance ratio (MDR), and emergence of summer annual weeds in a no-tillage soybean system. A 3 year field study with treatments consisting of six systems was conducted: no-tillage single cropping, no-tillage cropping following winter barley and tillage single cropping, respectively with and without herbicide application. The MDR of perennial weeds increased annually in the no-tillage fields in spring, but summer annual weeds were abundant in all fields, including the no-tillage fields in summer. Grasses, for example Digitaria ciliaris (Retz.) Koeler, were especially abundant in the no-tillage fields. The MDR of summer annual weeds, especially grasses in the barley and soybean fields, were much lower than for the no-tillage single soybean fields. Densities of D. ciliaris and Echinochloa crus-galli (L.) Beauv. var. crus-galli in the no-tillage single soybean fields were much greater than in the tilled fields, with few exceptions. In contrast, broad-leaved weeds emerged more in tilled fields than in the no-tillage fields. Winter barley suppressed emergence of summer annual weeds, especially during the first 3 years. The MDR for grasses in summer showed a good correlation with the frequency of emergence for grasses every year. These results showed that the increase in the volume of grasses in summer resulted mainly from an increase in the frequency of emergence, and that the suppression of grasses by winter barley resulted mainly from suppression of the emergence frequency. Soybean yields were higher in the barley and soybean fields for the first 2 years.     

Effect of Yucca schidigera with or without nisin on ruminal fermentation and microbial protein synthesis in sheep fed silage- and hay-based diets

A 4 × 6 Youden square design was used to study manipulating effect of Yucca schidigera with or without nisin on rumen fermentation characteristics and microbial protein synthesis in sheep fed silage‐ and hay‐based diets. Four ruminally canulated wethers were given isonitrogenous diets of timothy silage and concentrate (85:15) (S), and timothy hay and concentrate (60:40) (H), on DM basis. The six experimental diets were: (i) S; (ii) S + 240 ppm of Yucca schidigera (SY); (iii) S + 240 ppm of Yucca schidigera + 6 mg/kg bodyweight (BW)^0.75 of nisin (SYN); (iv) H; (v) H + 240 ppm of Yucca schidigera (HY); and (vi) H + 240 ppm of Yucca schidigera + 6 mg/kg BW^0.75 of nisin (HYN). Rumen pH was higher (P < 0.01) in sheep fed SYN diet than those fed S diet. Concentration of ammonia‐N (NH₃‐N) was significantly lower (P < 0.05) in sheep fed SY, SYN, HY, HYN than those of S and H. Total volatile fatty acids concentration was significantly lower (P < 0.05) in HYN than in H diet and tended to be higher in sheep fed H diets than those fed S diets. There was a significantly higher (P < 0.01) efficiency of microbial nitrogen synthesis in the rumen of sheep fed on HY diet than those fed on H diet.     

Circular Leaf Spot of Sweet Basil Caused by <Emphasis Type="Italic">Cercospora guatemalensis </Emphasis>New to Japan

A leaf spot disease on sweet basil (Ocimum basilicum L.) was observed in Chiba Prefecture in 1997. The lesions were amphigenous, circular to irregular, hygrophanous, dark brown. Stromata were amphigenous, composed of a few brown cells. Conidia with a thickened truncate base, filiform to cylindrical, hyaline, were produced from conidiophores with thickened conidial scars. These morphological characteristics agreed with those of Cercospora guatemalensis Mueller et Chupp. This species was new to Japan. The symptoms appeared 10 days after inoculation and the inoculated fungus was re-isolated. Artificial sporulation and detection from commercial seeds were not successful. Received 7 May 2001/ Accepted in revised form 7 August 2001     

Brown Leaf Spot on Lantana spp. Caused by Pseudocercospora guianensis

Brown leaf spot of Lantana camara L. and L. montevidensis Briq. caused by Pseudocercospora guianensis (Stevens et Solheim) Deighton was found in Shizuoka, Chiba, Kagoshima and Okinawa Prefectures. Pathogenicity of isolates from the leaf spots was examined, and a taxonomic study as well as identification of the causal fungus was carried out. Similar leaf spots appeared on 7 to 25 days after inoculation with the isolates on Lantana spp., and the same fungus was re-isolated from the inoculated leaves. Two hitherto known Pseudocercospora species on Lantana, P. guianensis and P. formosana, were considered to be variations within one species, and we identified the causal fungus as P. guianensis due to priority. Received 25 September 2000/ Accepted in revised form 20 May 2001     

Comparison of the functions of the barley nicotianamine synthase gene HvNAS1 and rice nicotianamine synthase gene OsNAS1 promoters in response to iron deficiency in transgenic tobacco

Barley ( Hordeum vulgare L.) nicotianamine synthase gene ( HvNAS1 ) expression in barley is strongly induced by Fe deficiency in the roots and rice ( Oryza sativa L.) nicotianamine synthase gene ( OsNAS1 ) expression in rice is induced by Fe deficiency both in the roots and in the shoots. In dicots, NAS genes are not strongly induced by Fe deficiency, and they function to maintain Fe homeostasis. Rice OsNAS1promoter::GUS or barley HvNAS1promoter::GUS was introduced into tobacco ( Nicotiana tabacum L.) and tissue specificities and systemic regulation of their expression were compared. A split-root experiment revealed that the HvNAS1 promoter exhibited functions similar to those of Fe-acquisition-related genes in tobacco roots, suggesting that this promoter responded to certain Fe-deficiency systemic signals and to the Fe concentration in the rhizosphere. The HvNAS1 promoter might harbor a type of universal system of gene expression for Fe acquisition. However, the OsNAS1 promoter did not respond to local application of Fe to the roots and induced GUS activities in mature leaves in response to Fe deficiency. This promoter might possess numerous types of cis -acting sequences that are involved in Fe metabolism.     

Detection and identification of rumen bacteria constituting a fibrolytic consortium dominated by Fibrobacter succinogenes

A fibrolytic consortium, dominated by the rumen cellulolytic bacterium Fibrobacter succinogenes, was artificially constructed on hay stems to detect and identify rumen bacteria that can potentially interact with F. succinogenes . Consortium-bacterial members were determined by DGGE and sequencing analysis targeted bacterial 16S rDNA. An artificial consortium was formed in a 2-step incubation of hay stems; the first step with group 1, 2 or 3 F. succinogenes strains, the second step with rumen fluid. After consortium formation, morphologically different bacteria were observed in association with F. succinogenes . DGGE exhibited more than 30 bands, the pattern of which depended on the F. succinogenes group. Sequencing suggested that Butyrivibrio fibrisolvens, Pseudobutyrivibrio ruminis , Clostridium sp., F. succinogenes group 2, Prevotella ruminicola and unclassified Bacteroides were prominent in the group 1 consortium and that Treponema bryantii , B. fibrisolvens , Acinetobacter sp, and Wolinella succinogenes were prominent in the group 2 consortium. However, in the group 3 consortium, F. succinogenes -like bacteria were microscopically undetectable, whereas cellulolytic Ruminococcus albus and F. succinogenes group 1 were prominent, suggesting that the group 3 cannot be a core member of this consortium. This study is the first attempt to identify bacterial members of a fibrolytic consortium dominated by a specific bacterium.