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51.
Some introduced frugivorous birds disperse introduced plants and are thus a substitute for extinct native birds. Introduced birds have negative and/or infrequently positive effects on local ecosystems. It is important for management of the ecosystems to understand the relationships between native and introduced frugivorous and plant species. In this study, we elucidated these relationships in Mukojima Island, the Bonin Islands, where was anthropologically deforested and Japanese White-eye Zosterops japonicus and some plants were already introduced. We examined the habitat selection of frugivorous birds, actual dispersed seeds in bird feces, and the distribution of the potentially dispersed plant species. The Japanese White-eye and the native, Blue Rockthrush Monticola solitarius, were dominant on this island. The former mainly used the forest area and dispersed only small seeds and frequently introduced plant seeds. The latter mainly used the open area and dispersed both small and large seeds. Some small-seed plants occurred not only in the forest but also in the open area. Their seedlings were distributed farther from their adult trees than the large-seed species. These indicate that small-seed plants would be more spread than the large-seed plants because the two bird species disperse their seeds in different environments. This introduced bird species may be important in vegetation recovery, although it may contribute to the distribution of introduced plants on this island.  相似文献   
52.
53.
Takahashi K  Okada J  Urata E 《Tree physiology》2006,26(8):1035-1042
Effects of relative shoot height and irradiance on shoot and leaf properties of Quercus serrata Thunb. saplings growing in the understory and in gaps were investigated. Photosynthetic photon flux (PPF) at the location of the shoot relative to that in the open (relative PPF; rPPF) and the height of the shoot base relative to tree height (relative height; rHeight) were measured for all current-year shoots of each sapling. Current-year shoot properties (length, leaf area, number of daughter shoots) and mortality, and leaf properties (mass per area (LMA) and nitrogen content per area (N(area))) were examined in relation to rPPF and rHeight. N(area) was used as a proxy for area-based assimilative capacity. Shoot length, leaf area per shoot and number of daughter shoots increased with increasing rHeight, especially in well-lit conditions. Shoot mortality decreased with increasing rHeight and rPPF. Both LMA and N(area) were positively correlated with rPPF, but not rHeight.  相似文献   
54.
Two cats showing chronic vomiting, diarrhea and weight loss were found to have leukocytosis with marked eosinophilia. Both cats were diagnosed with hypereosinophilic syndrome by the findings of increased eosinophils and their precursors in the bone marrow, eosinophilic infiltration into multiple organs, and exclusion of other causes for eosinophilia. Although cytoreductive chemotherapy with hydroxycarbamide and prednisolone was performed, these two cats died 48 days and 91 days after the initial presentation.  相似文献   
55.
Feline leukemia virus (FeLV), which is subclassified into three subgroups of A, B and C, is a pathogenic retrovirus in cats. FeLV-A is minimally pathogenic, FeLV-C can cause pure red cell aplasia, and FeLV-B is associated with a variety of pathogenic properties such as lymphoma, leukemia and anemia. FeLV-induced neoplasms are caused, at least in part, by somatically acquired insertional mutagenesis in which the integrated provirus may activate a proto-oncogene or disrupt a tumor suppressor gene. The common integration sites for FeLV have been identified in six loci with feline lymphomas: c-myc, flvi-1, flvi-2 (contains bmi-1), fit-1, pim-1 and flit-1. Oncogenic association of the loci includes that c-myc is known as a proto-oncogene, bmi-1 and pim-1 have been recognized as myc-collaborators, fit-1 appears to be closely linked to myb, and flit-1 insertion is shown to be associated with over-expression of a cellular gene, e.g. ACVRL1. Thus, identification of common integration sites for FeLV is a tenable model to clarify oncogenesis. Recent advances in molecular biology and cytogenetics have developed to rapidly detect numbers of retroviral integration sites by genome-wide large-scale analyses. Especially, polymerase chain reaction (PCR)-based strategies and chromosome analyses with fluorescence in situ hybridization (FISH) will be applicable for studies on FeLV.  相似文献   
56.
We used daily records from provincial Japanese weather stations and monthly test‐day records of milk production to investigate the length of the lags in the responses of cows’ milk yield and somatic cell score (SCS) to heat stress (HS). We also investigated the HS thresholds in milk yield and SCS. Data were a total of 17,245,709 test‐day records for milk and SCS in Holstein cows that had calved for the first time between 2000 and 2015, along with weather records from 60 weather stations. Temperature–humidity index (THI) values were estimated by using average daily temperature and average daily relative humidity. Adjusted THI values were calculated by using temperature, relative humidity, wind speed, and solar radiation. The model contained herd, calving year, month of test day, age group, days in milk, and THI as a fixed effect. THIs for each day from 14 days before the test day until the test day were used to represent the HS effects. The HS occurring 3 days, and between 8 and 10 days, before the test day had the greatest effect on the milk yield and SCS, respectively. The threshold THI values for the HS effect were about 60–65 for both traits.  相似文献   
57.
Ehrlichia muris DNA was detected in the blood of sika deer (Cervus nippon yesoensis) by species-specific PCR based on the citrate synthase gene, which was shown to be more sensitive than species-specific PCR based on the 16S rRNA gene. Among 102 deer examined, one deer was positive. Deer may be a possible mammalian reservoir of E. muris.  相似文献   
58.
The spatial distribution patterns of the attack on fresh logs ofPasania edulis was studied for the oak borer,Platypus quercivorus (Murayama), and two species of Scolytid ambrosia beetles,Xylosandrus crassiusculus (Motschulsky) andXyleborus attenuatus Blanford, in 1994 and 1995. On the logs where onlyP. quercivorus attacked, the entry holes were distributed uniformly when attack intensity was low. However, the distribution pattern became more aggregated with the increase in attack intensity. On logs where bothP. quercivorus and the two Scolytid species attacked, there was a negative association between the spatial distribution of the entry holes ofP. quercivorus and that of scolytids. Simultaneous attack of two scolytids also increased the degree of aggregation of the entry holes ofP. quercivorus. The entry holes of scolytids were distributed in groups irrespective of the attack intensity of scolytids andP. quercivorus. These results suggest an asymmetrical interspecific relationship betweenP. quercivorus and scolytids. Concentration of the entry holes ofP. quercivorus in a small area may cause a considerable decline in the reproductive success in the galleries constructed there.  相似文献   
59.
To determine the sexual maturity of fourteen male wild-caught hawksbill turtles [straight carapace length (SCL) range 63–79 cm] held in captivity, we investigated their hormone levels in blood and morphological characteristics. Male turtles were divided into two groups: five individuals showing mating behavior (group A) and nine individuals not showing mating behavior (group B). Then, seasonal changes of plasma testosterone of both groups were studied. We also tried to determine male maturity based on tail elongation (TE) index, i.e., the ratio of tail length (TL) to SCL. Plasma testosterone level of group A gradually increased during premating and then sharply declined to low levels between mating and postmating seasons. In contrast, that of group B remained low during the experimental periods. The distinct seasonal changes of plasma testosterone levels of groups A and B correlated with their maturity. Furthermore, males were clearly divided into mature and immature based on TE values >0.35 and <0.33, respectively, corresponding to results based on plasma testosterone levels. Our results indicate that TE can be used more conveniently and accurately to determine maturity of male hawksbill turtles in captivity.  相似文献   
60.
A thermally selected strain of rainbow trout has been established by selective breeding since 1966 in Miyazaki, Japan. In the present study, we compared the critical thermal maxima (CTMs), the temperatures at which organisms reach a predefined sublethal endpoint and lose their equilibrium, between a thermally selected and two normal (Donaldson) strains of rainbow trout. The CTM of one normal strain from Nikko (Nikko strain) acclimated to 20 °C (29.7 °C) was significantly lower than those of the thermally selected strain (30.0 °C) and the other Donaldson strain from Aomori (29.9 °C) (P?<?0.05). The F1 generations, F1T and F1N, were produced by crossing thermally selected strain females with Nikko strain males and Nikko strain females with thermally selected strain males, respectively. No significant difference was observed in the CTM between F1T [30.1?±?0.15 °C (n?=?30)] and F1N [30.1?±?0.16 °C (n?=?30)] (P?>?0.05) for fish acclimated to 20 °C, suggesting that the F1 offspring inherited the thermal tolerance trait from one thermally selected strain parent irrespective of whether it was the male or female. F2 offspring of F1T or F1N also showed the thermal tolerance trait. The coefficients of variation for CTM were also compared among all the datasets obtained in the present study and their values for F1 hybrids were lower than those of the parental generation of the Nikko strain (P?<?0.05). In contrast, the coefficients of variation of F2s were the same as those of their parental generation. Furthermore, the thermally selected strain and Nikko strain as a reference family provide a F2 generation for segregating phenotypes, which is required for in-depth genetic analysis of the thermally selected rainbow trout strain.  相似文献   
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