Breed differentiation among Japanese native chickens by specific skull features determined by direct measurements and computer vision techniques

1. Inter-breed morphological comparisons were made among 11 breeds of Japanese native chickens (Gifujidori, Hinaidori, Shokoku, Totenko, Tomaru, Satsumadori, Shamo, Koshamo, Koeyoshi, Chabo and Nagoya), White Leghorn, broiler chickens (Chunky) and red junglefowl collected in the Philippines, based on results of direct measurements and analysis by computer vision techniques of the skull. 2. Analysis of direct measurements identified two groups of chicken: a small type that included the Chabo, Koshamo, red junglefowl, Gifujidori and Shokoku and a large type that included the remaining breeds studied. These groupings were made based on size determined both in the first (PC1) and second principal component (PC2). The greatest length of the cranium and condylobasal length greatly contributed to the morphological differences between these two groups. 3. Analysis by computer vision techniques, however, identified three groups: the Bantam group (which includes red junglefowl), Shokoku group and Shamo group. White Leghorn clustered within the Shokoku group while the broiler chicken belonged to the Shamo group. The region around the junction of the neural cranium and the visceral cranium contributed greatly to the morphological differences among breeds, both in the PC1 and PC2.     

Chromosomal regions controlling anther culturability in rice (Oryza sativa L.)

Diallel analysis has revealed that anther culturability in rice (Oryza sativa L.) is a quantitative trait controlled by the nuclear genome. Mapping of anther culturability is important to increase the efficiency for green plant regeneration from microspores. In the previous study, we detected distorted segregation of RFLP markers in rice populations derived from the anther culture of an F₁ hybrid between a japonica cultivar ‘Nipponbare’ and an indica cultivar ‘Milyang 23’. To clarify the association between chromosomal regions showing distorted segregation and anther culturability, the anther culturability of doubled haploid lines derived from the same cross combination was examined, and the association between alleles of the RFLP markers, which exhibiting the most distorted segregation on chromosomes 1, 3, 7, 10 and 11, and the anther culturability was evaluated. One region on chromosome 1 was found to control callus formation from microspores, and one region on chromosome 10 appeared to control the ratio of green to albino regenerated plants. In both regions, the Nipponbare allele had positive effects. Three regions on chromosomes 3, 7 and 11, however, showed no significant effect on anther culturability. This revised version was published online in August 2006 with corrections to the Cover Date.     

A set of near-isogenic lines for blast resistance genes with an Indica-type rainfed lowland elite rice (Oryza sativa L.) genetic background

A set of near-isogenic lines for blast resistance genes was developed by using an Indica-type elite rice variety, IR49830-7-1-2-2, suitable for the rainfed lowland conditions in the tropics, as a genetic background. Initially, we revealed that IR49830-7-1-2-2 harbors five blast resistance genes - Pia, Pib, Pik-s, Pita, and Pi11(t) - by using a differential system involving 19 selected standard blast isolates from the Philippines. Based on this result, we developed nine near-isogenic lines (NILs) targeting eight resistance genes - Pik, Pi7(t), Pi3, Pi5, Pita-2, Piz-5, Pish, and Pi9 - by recurrent backcrossing. The introgression of each resistance gene in the NILs was confirmed by reaction patterns to the blast isolates, allelism tests, and DNA marker analysis. In addition, a genome-wide DNA marker survey revealed that most of the chromosome regions in each NIL were of the IR49830-7-1-2-2 type. The agricultural characteristics of most of the developed NILs were almost the same as those of IR49830-7-1-2-2. Moreover, with one exception, they showed submergence tolerance similar to IR49830-7-1-2-2. The developed NILs could be used as a multiline variety suitable for the rainfed lowland in the tropics.     

Detection of Pythium aphanidermatum in tomato using loop-mediated isothermal amplification (LAMP) with species-specific primers

A loop-mediated isothermal amplification (LAMP) reaction with a primer set designed from the rDNA ITS sequence of P. aphanidermatum was developed. Results of a specificity test using 57 strains of Pythium spp. indicated that the LAMP assay gave no cross reactions in other 39 Pythium species, 11 strains of Phytophthora spp. and eight other soil borne pathogens. The detection limit was 10 fg of genomic DNA, which was ten times the sensitivity of the polymerase chain reaction. The LAMP assay was applied to hydroponic solution samples from tomato fields, and the results were compared to those of the conventional plating method. LAMP was observed to be effective for the specific detection of P. aphanidermatum. Furthermore, P. aphanidermatum was detected directly in tomato roots infected with P. aphanidermatum without DNA extraction. The LAMP method established in this study is a simple, sensitive and rapid tool for the detection of P. aphanidermatum.     

Usefulness of computed tomography for cryptorchidism in bulls

Cryptorchidism is defined as the failure of the testis to descend into the scrotal position. Bulls with cryptorchidism have problems in both meat quality and husbandry management; thus, it is greatly important to accurately identify the retained testis and remove it during the early stage. Abdominal computed tomography (CT) was performed under general anesthesia in 34 bulls aged 3–9 months with cryptorchidism. All bulls underwent laparoscopic or incision approach for cryptorchidectomy, and 40 testes were dissected. The detection rates of retained testes were 64.5% in the abdominal cavity and 100% in the subcutaneous inguinal region, and the total detection rate was 72.5%. Furthermore, all cases in this study were suspected to have intra-abdominal cryptorchidism in primary care, but CT revealed that 22.5% of cases had cryptorchidism in the subcutaneous inguinal region. The CT value (mean ± standard deviation) of the retained testes was 20.96 ± 7.54 Hounsfield Unit, and the CT value and size of the retained testes showed a positive weak correlation with bovine age. Therefore, there is the demerit that general anesthesia and a huge device are necessary; nevertheless, CT is suggested to be useful in identifying the location of retained testes and selecting an appropriate surgical approach in bulls with cryptorchidism. Moreover, CT findings suggested that the maturation of the retained testes might depend not on the descending process but on age.     

Changes in the level of plasma cortisol, progesterone and total testosterone in developing hairless dogs.

Changes in the levels of plasma cortisol, progesterone and total testosterone were examined in developing hairless and haired dogs. Cortisol levels in the hairless dogs seemed to be higher than those in haired dogs within the age of 4-5 weeks. No apparent changes were seen in the level of plasma progesterone between the groups of hairless females and haired females. Total testosterone levels in hairless males showed to be significantly lower than those in haired males at the age of 13-21 weeks.     

Influence of weaning age on the villous height and disaccharidase activities in the porcine small intestine

Body weight gain after weaning is correlated with villous height and disaccharidase activity. This evidence suggests that the maintenance of the small intestinal structure and function after weaning is important for the growth of piglets. We demonstrated that the influence of weaning age was obtained by disaccharidase activities and villous height in eight sections of the porcine small intestine. Therefore, we designed three weaning ages (weaned at the ages of 14, 21 or 28 days) and the piglets were slaughtered after 7 or 14 days post‐weaning. The remaining suckling piglets were slaughtered at the age of 1, 7, 14, 21 and 28 days. Four piglets were slaughtered at each event; therefore, 44 piglets were used in this study. Villous height and disaccharidase activities were measured in each section of the small intestine. Early weaning such as that at 14 days had severe influence on villous and disaccharidase activities. In particular, weaning of 14‐day‐olds did not result in maltase activity at least 2 weeks post‐weaning. Accordingly, the weaning age of crossbred piglets is recommended to be at least 21 days or more on the basis of villous height and disaccharidase activity analyses.     

Immunolocalization of gastrin-releasing peptide (GRP) in the uteroplacenta of the mouse deer

The considerable phylogenetical differences between mouse deer and other ruminants have been established by means of DNA sequence analysis and anatomical observations. To clarify the physiological role of the uteroplacenta of the mouse deer, immunohistochemical observation was attempted by using GRP, which has been suggested as a novel regulatory peptide in the female reproductive tract, as an indicator to compare with other ruminants. Strong positive reactions for the GRP were detected in the uterine glands of the pregnant animals, but not in the non-pregnant ones. Although the placenta of the mouse deer is categorized as a diffuse placenta that is different from other ruminants' polycotyledonary placenta, in terms of GRP immunoreactivity, the mouse deer placenta can be classified as a synepithecholial placenta like the other ruminants'. The secretion of GRP from the uterine glands is of some importance to the fetus in the mouse deer.     

Location of sympathetic postganglionic and sensory neurons innervating the testis in the male chicken

Sympathetic postganglionic and sensory neurons were labelled by injections of horseradish peroxidase into the testis of the male chicken. The total number of labelled neurons in the paravertebral, prevertebral, dorsal root and nodose ganglia was 943 on average for five chickens. Sympathetic postganglionic neurons were located in the paravertebral ganglia T3-LS3 (10% of the total number of labelled neurons), especially in T6 and T7, and in the prevertebral ganglia adjacent to the adrenal glands and aorta (19%). They were found almost ipsilaterally. No labelled neurons were observed in the dorsal motor nucleus of the vagus. Sensory neurons were found bilaterally in the dorsal root ganglia T2-LS3 (71%), especially in T5 to T7. Over a quarter of labelled sensory neurons were located in the contralateral dorsal root ganglia. In the nodose ganglia, only a few labelled sensory neurons were observed (much less than 1%). These results indicate that, unlike the ovary, the testis of the chicken tends to be innervated by ipsilaterally located sympathetic postganglionic and sensory neurons, with the sensory neurons being more numerous than the sympathetic postganglionic neurons.