Geographical variation in skull morphology of gray-bellied squirrel Callosciurus caniceps

The geographical variation of the gray-bellied squirrel (Callosciurus caniceps) was examined using osteometry of skull in Southeast Asia. From the principal component analysis (PCA), the plots of the northern localities from Nan to Kanchanaburi and those of the southern localities from Narathiwat to Kuala Lumpur in male were completely separated. In female, the plots of the locality from Uttradit to Kanchanaburi and those of the locality from Pattani to Negri Sembilan were completely separated. We called these northern localities and southern localities which are distinguished by the PCA as N group and S group. The size and shape of the skulls of these squirrels indicated the differences between N group and S group from t-test and U-test. These results may be influenced by the two transitions of the phytogeography around the southernmost locality in N group and the northernmost locality in S group in the peninsular Thailand and Malay Peninsula. Localities which are located between N and S groups were called the Middle (M) group. From the PCA among N, S groups and each locality of M group, the plots of localities such as Prachuap Khiri Khan, Chumphon, Krabi, Nakhon Si Thammarat and Trang in both sexes of M group could not be separated from those of N and S groups. We suggest that the sympatric distribution of N and S groups and the hybrid of N and S populations may be seen in these localities of M group.     

Effect of radical scavengers on canine peripheral blood mononuclear lymphocyte-mediated cytotoxicity and production of active oxygen

Production of active oxygen by canine peripheral blood mononuclear lymphocytes (PBLs) from beagle dog was examined by luminol-dependent chemiluminescence production. The canine PBLs rapidly produced the active oxygen in parallel with the number of cells when PBLs were cocultured with canine leukemia-derived CL-1 cells as target cells. Cytolysis of the target cells and active oxygen production were inhibited linearly by the addition of benzoic acid and n-propyl gallate as hydroxyl radical scavenger. However, superoxide dismutase and tiron which are scavengers of superoxide anion did not inhibit the cytotoxicity so much at low concentrations that inhibited the induction of luminol-dependent chemiluminescence. These results suggest that hydroxyl radical production by stimulated PBLs might be playing a major role of cytotoxic action in the case of canine system.     

Spin-trapping detection of superoxides in polymorphonuclear leukocytes stimulated with serum-opsonized zymosan

To clarify where oxygen radicals are generated in polymorphonuclear leukocytes (PMNs) during phagocytosis, superoxides (O2-) from opsonized symosan (OZ)--stimulated human PMNs were detected by the ESR and spin-trapping methods. PMNs were preactivated with OZ for the indicated periods of time at 37 degrees C. Then a spin-trapping agent, 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), was added to them, and they were further incubated for 30 sec for ESR observations. The ESR spectra consisted of two components due to the DMPO-OOH and DMPO-OH spin adducts. To clarify where these spin-adducts were present, cells were separated from extracellular fluid by brief centrifugation and resuspended in Hanks' balanced salt solution. ESR examination of two fractions showed that the DMPO-OOH adducts was present in the cell fraction, whereas the DMPO-OH adducts were present in the extracellular fluid. When DMSO was used as a scavenger of hydroxyl radicals (.OH), DMPO-CH3 adducts were observed in the fluid fraction but not in the cell fraction. Both spin adducts were completely abolished by Cu, Zn-SOD but not catalase. These results indicated that O2- were produced inside phagosomes of OZ-stimulated PMNs and .OH were produced outside them by spontaneous decomposition of the DMPO-OOH adducts.     

Reproductive and growth performance in Jin Hua pigs cloned from somatic cell nuclei and the meat quality of their offspring

Somatic cell cloning is expected to be a valuable method for conserving genetic resources in pigs. In this study, we compared the reproductive and growth performance of Jin Hua cloned pigs with that of naturally bred Jin Hua pigs. In addition, we generated offspring from the cloned sows and examined the productivity and quality of meat in the progeny. The birth weights and growth rates of somatic cell-cloned pigs were similar to those of Jin Hua pigs. The cloned pigs reached puberty very early, and this is typical of the Jin Hua breed. Furthermore, reproductive performance, in terms of traits such as gestation period, litter size, and raising rate in the cloned pigs were similar to Jin Hua pigs. Although the offspring of the cloned (OC) pigs had lower birth weights than the Jin Hua breed, the daily weight gain of the OC pigs was significantly higher, especially at the finishing stage. The carcass quality of the OC pigs had similar characteristics to the Jin Hua breed, namely thick back fat and a small loin area. Furthermore, the meat qualities of the OC pigs were similar to those of Jin Hua pigs in terms of intramuscular fat content and tenderness. These results demonstrate that cloned pigs and their offspring were similar to the Jin Hua breed in most of the growth, reproductive, and meat productive performances. This strongly suggests that pigs cloned from somatic cell nuclei have the potential to be a valuable genetic resource for breeding.     

Micronucleus test in mice fed on an irradiated diet

A mutagenicity study was carried out in mice fed on a gamma-irradiated diet. As an indicator of mutagenic activity, we observed an incidence of micronuclei in erythrocytes. The average body weight of the mice fed on the diet irradiated to dose range of 400-1,000 kGy decreased, and the mice fed on the 800-1,000 kGy-irradiated diet died during the period from 8 to 14 days after the start of feeding. On the other hand, when the mutagenic activity of the irradiated diet was tested by observing occurrence of micronucleus in erythrocytes, no significant increase was recognized. These results indicated that the irradiated diet had no mutagenic activity, even though it possessed a toxic effect on the growth of mice.     

The effect of alternating temperature on the rest break process of male flowers of Cryptomeria japonica D. Don

In order to develop a model for predicting the period of male flower anthesis in Cryptomeria japonica, it is requisite to clarify the rest break process in male flowers. In this study, the effect of alternating temperatures in a daily cycle on rest break was investigated using twigs bearing male flowers from three clones of C. japonica. Four temperature treatments with the same daily mean of 8°C were applied to sample twigs over a period of 35 days: (1) 8°C constant (TR-A); (2) 7°–10°C alternating (TR-B); (3) 5.5°–13°C alternating (TR-C); and (4) 4°–16°C alternating (TR-D). After treatment, the sample twigs were forced to bloom at a constant temperature of 16°C, and the cumulative effective temperatures (CETs) required for anthesis were compared. While the CETs for anthesis were the same for TR-A and TR-B, that for TR-C was significantly higher. After TR-D, almost no male flower bloomed, indicating that this treatment was ineffective in breaking rest. When considering these results on an hour basis, it was a reasonable interpretation that 13°C had no effect on breaking rest while the temperatures below 10°C were all equally effective. On the other hand, temperatures of 16°C or above were considered to have an antagonizing effect that cancels the effects of chilling temperatures below 10°C. These results suggest that the effects of high temperatures during the daytime in chilling periods should be properly incorporated into a model of the process by which rest of male flowers is broken.     

The antiproliferative effect of bovine lactoferrin on canine mammary gland tumor cells

Lactoferrin has several biological activities, including antitumor activities in some human and animal tumor cells. Clinical trials have been carried out in human medicine based on these effects. However, the antitumor effects of lactoferrin in veterinary medicine remain unknown. In this in vitro study, we demonstrated that co-incubation of canine mammary gland tumor cells (CIPp and CHMp) and bovine lactoferrin induced growth arrest of tumor cells. This growth arrest was associated with induction of G1 arrest. Furthermore, this effect was stronger in tumor cells than in normal cells. These findings demonstrate that bovine lactoferrin has anti-tumor activity in canine mammary tumors and has the potential for use in tumor-bearing dogs.     

Zoogeographical barriers causing discontinuous osteometrical variations in the northern treeshrew skulls

Morphological variation of the skull was examined in the northern treeshrew (Tupaia belangeri) from various localities across Southeast Asia. Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct morphological characteristics compared to other populations from Thailand and Laos, and Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand plots segregation in the scatteregrams of canonical discriminant analysis. Since the skulls of the population from North Vietnam were morphologically similar to those form central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of Mekong River was not clearly confirmed. The population of the Kanchanaburi in western Thailand is clearly smaller in size compared to the other populations. The southern border of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani Line. In the northern treeshrew, which is distributed from southern China to Bangladesh and southern Thailand, we have detected osteometrical geographical variation driven by geography. These results indicate that the skull morphology in the Tupaia glis-belangeri complex distinctively differs in South Vietnam, western Thailand, and southern Thailand. The zoogeographical barrier and factor separating these districts are expected to clarify in the future.     

Spatial variation of quantitative color traits in green and black types of sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis> (Stichopodidae) using image processing

It has been suggested that the Japanese sea cucumber, Apostichopus japonicus, has three color types (red, green, and black), although the qualitative difference between the color types, particularly between the green and black types, is unclear because of continuous color variation among color types. This study elucidated the color variation between green and black types using image processing (RGB, red–green–blue system) and multivariate analysis to demonstrate whether or not the black and green types can be quantitatively classified. Moreover, spatial variation of the RGB value among various local sites was clarified to estimate potential environmental factors that may affect the color variation. The series of analyses revealed that a quantitative boundary between green and black types could be provisionally established, and also that spatial variability in the intermediate (continuous) color trait between green and black types was significant. Potential environmental factors (depth and industrial activity index) were correlated with the color traits in both color types. These results suggest that the green and black types cannot be regarded as independent color traits and that the color variation between green and black types may be influenced by local environmental factors.     

Lipid peroxides and antioxidants in serum of neonatal calves

OBJECTIVE: To examine the association between oxidative stress and antioxidants in neonatal calves after birth. SAMPLE POPULATION: Sera from 6 healthy Holstein-Friesian cows and 7 of their newborn calves were obtained at various intervals after birth. PROCEDURE: Lipid peroxides in serum of cows and their newborn calves were estimated by measuring concentrations of thiobarbituric acid-reactive substances (TBARS). The antioxidative activities of neonatal sera were evaluated by measuring their superoxide-scavenging activities, ferroxidase activities, and the concentration of bilirubin-associated albumin. RESULTS: Concentration of TBARS in neonatal sera within 1 day after birth was significantly higher than concentrations > or = 2 days after birth and concentrations in serum of the dams. In contrast, antioxidative activities of neonatal sera, evaluated on the basis of superoxide-scavenging activities, ferroxidase activities, and concentration of bilirubin-associated albumin 3 hours after birth, were significantly lower than antioxidative activities in sera of the dams. CONCLUSIONS: Susceptibility of calves to oxidative stress during the neonatal period may be explained by the immature defense system against superoxide radicals.