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31.
M. Mandolfino G. Cimino A. Scuteri R. Cordì L. Romano 《Cell biology international》1994,18(4):279-288
Zinc movement across eel and human red blood cell membranes was measured by atomic absorption spectrophotometry. It was observed that:
- 1) In human red blood cells zinc uptake is twice as rapid as in fish red blood cells over a temperature range of 10-40°C. The low rate of zinc uptake in eel red blood cell may be simply the side effect of different surface area to volume ratios for the differences in cell size or, it may be due to the low permeability of bicarbonate through the red blood cell membranes.
- 2) Zinc uptake measured in eel and human red blood cells treated and untreated with external trypsin shows different features. The zinc uptake was reduced by about 40% in treated eel red blood cells with respect to the total uptake of untreated red blood cells. Human red blood cells treated and untreated with trypsin do not show any differences in the amount of zinc transported.
- 3) In fish red blood cells, zinc uptake in NANO3 medium is markedly reduced, compared with that measured in NaCl medium. The [Zn2+i slightly increases in the presence of bicarbonate. In human red blood cells in NANO3 medium the zinc uptake is strongly reduced and the presence of bicarbonate marginally increases the zinc influx.
- 4) In eel red blood cells there seem to be two independent pathways for zinc uptake: one DIDS-sensitive and the other DIDS-insensitive. DIDS 10 μM inhibits only 64% of the total zinc transported. Iincreasing the DIDS concentration did not give more inhibition. In human red blood cells only one DIDS-sensitive pathway for zinc transported seems to exist, because, 2,5 μM DIDS inhibits 97% of zinc uptake.
32.
Capture and blood sampling in wild primate populations are difficult. For this reason, we need to use DNA extracted from the
hair or feces of target animals. The polymerase chain reaction (PCR) method, which amplifies small volumes of DNA, provides
an ideal means for studying DNA variations in wild populations. Three sets of PCR primers which amplify highly polymorphic
(GT/AC)n dinucleotide repetitive regions were synthesized from DNA sequences of Japanese macaques (Macaca fuscata). One of the primer pairs detected at least seven alleles in one captive Japanese macaque group. Also, the fathers of four
offspring whose mothers had died in a captive group of Japanese macaques were identified. In such cases, the father cannot
be determined by the previous DNA fingerprinting method based on the polymorphism of minisatellite DNA. These primers were
further tested with some species of the Cercopithecidae, e.g. grivet monkeys (Cercopithecus aethiops tantalus) and hamadryas baboons (Papio hamadryas). The results obtained suggest that these primers can detect stably inherited polymorphic regions in each species. 相似文献
33.
Seasonal changes and yearly gross canopy photosynthetic production were estimated for an 18 year old Japanese larch (Larix leptolepis) forest between 1982 and 1984. A canopy photosynthesis model was applied for the estimation, which took into account the
effect of light interception by the non-photosynthetic organs. Seasonal changes in photosynthetic ability, amount of canopy
leaf area and light environment within the canopy were also taken into account. Amount of leaf area was estimated by the leaf
area growth of a single leaf. The change of light environment within the canopy during the growing season was estimated with
a light penetration model and the leaf increment within the canopy. Canopy respiration and surplus production were calculated
as seasonal and yearly values for the three years studied. Mean yearly estimates of canopy photosynthesis, canopy respiration
and surplus production were 37, 13 and 23 tCO2 ha−1 year−1, respectively. Vertical trend, seasonal changes and yearly values of the estimates were analyzed in relation to environmental
and stand factors. 相似文献
34.
The density of a Japanese serow (Capricornis crispus) population, which has been in stable habitat conditions and free from hunting and predation, was investigated by direct
observation of serows at Kusoudomari (336 ha), Wakinosawa village, Aomori Prefecture, Japan, during 1977–89. The vegetation,
composed of mature mixed forest ofThujopsis with deciduous trees (43.2%), secondary forest of deciduous trees (23.4%) and a plantation of coniferous trees (30.0%) showed
little change during the study period. The serows were counted 17 times each winter for 14 consecutive years. The serow population
maintained a stable density with a mean of 12.5 individuals km−2 (SD=1.4) ranging from 8.6 to 14.6 km−2. The ratio of the proportion of kids (<1 year old) to serows more than 1 year old decreased, but density did not decrease
during the study period. Though extremely severe winters with heavy snowfall in 1984–86 caused a decline in serow density,
the density recovered within a few years. It was considered that the stability of the serow density resulted mainly from the
stable food supply and the lack of human disturbance, such as forest cutting in the habitat. Stable population density for
a long period is probably related to the social organization of the serow. 相似文献
35.
36.
The cells dissociated from developing embryos of Japanese flounder (Paralichthys olivaceus) are cultured in vitro to examine the developmental fate of their pigment cells in relation to establishment of bilaterally asymmetric integumental coloration in vivo. When neurula embryos are dissociated using trypsin–EDTA in Dulbecco's modified Ca2+–, Mg2+–free phosphate buffered saline and then cultured in vitro using L–15–based fetal calf serum–supplemented growth medium at 20°C, numerous pigment cells appear twice in the same culture with an interval of approximately 1 month even under similar culture conditions. The first group of pigment cells, which is relatively larger in cell size (about 70 μm wide) and lower in cell density, emerges within 12 hr after plating, whereas the second, which is far smaller in cell size (about 30 μm) and overwhelmingly higher in cell density than the first, does so about 1 month after plating. The timing of their appearances in vitro is in good accordance, respectively, with that observed for the larvae under normal development in vivo; the first group appears at the period corresponding to hatching, whereas the second at the period corresponding to the completion of metamorphosis. Light microscopic examinations disclose that each group of pigment cells is composed of black melanophores and reflecting leucophores, and that the population density of melanophores and leucophores in the first group at the climax of appearance is approximated as 1:4. Typical xanthophores that are distributed in the skin of the larvae of this species are scarcely observed in culture in vitro. Because of their dual synchronous appearances with about 1 month interval under the similar culture conditions, and because of their low proliferative activity during the periods from the first appearance to the second, it is presumed that both groups of pigment cells are installed with a clock set differently for their differentiation. Light and electron microscopic immunocytochemistry on cultured cells using the HNK–I antibody, which marks avian migratory neural crest cells, both disclose that the antibody cross–reacts with all these pigment cells, and that a certain number of immunoreactive unpigmented cells exist even at the time of the second appearance of pigment cells. These findings would imply that the second group of pigment cells served in a form of undifferentiated propigment cells up to metamorphosis, at which they start to differentiate under control of a clock presumably set during neurulation. 相似文献
37.
Seasonal population dynamics of Puraquzmperia tenerrima (Linstow) in the European eel Anguillu anguillu (Linnaeus) have been investigated in three localities in Devon, southwest England. The nematode is common and exhibits very similar seasonal patterns in changes of prevalence and abundance in the three localities. The population increases over winter through to late spring or early summer as the recruitment of the new generation occurs throughout this period. Reproduction of the nematode starts in spring. A sharp decrease of prevalence and abundance accompanies or follows reproduction, and infection levels are very low in autumn and early winter. The dispersion pattern of the nematode varies with the infection levels from over-dispersion in spring and early summer to almost random dispersion in autumn and winter. It is suggested that P. tenerrimu is a common specific parasite of eels, especially in small streams or rivers and that insect larvae or species of crustaceans might serve as intermediate hosts for the nematode. 相似文献
38.
39.
Akio Mori 《Primates; journal of primatology》1995,36(1):11-26
The feeding process of Japanese monkeys on soy beans which were scattered over a sandy beach on Koshima islet was studied.
Younger monkeys were able to pick up more beans when 8 kg of beans were divided and given two times (“two times feeding”)
than when the whole amount (8 kg) of beans was given at one time (“one time feeding”). The effect of saturation of the food
intake capacity in younger monkeys at the first feeding in “two times feeding” did not appear at the second feeding one hour
later. The minutely intake of soy beans (feeding speed) for each age class was analyzed. The decline of feeding speed in adult
females after the peak in “one time feeding” was not related to the decline in density of beans on the ground, and this decline
was caused by saturation of their food intake capacity.
Adult females were divided into four classes according to their dominance rank order: high, lower-high, higher-low, and low
classes. The total amount of intake in “one time feeding” was far larger in the high class than in any of the other classes.
The total amount of feeding in the first feeding of “two times feeding” increased in accordance with rise in the dominance
rank class, and there was no relation to rank and total feeding amount in the second feeding of “two times feeding.” Differences
existed in the process of feeding between the rank classes. The feeding speed of the low class was as high as that of the
high class on the curve of minutely intake, while the low class stopped feeding much earlier than the high class. The lower-high
class displayed a low feeding speed, and stopped feeding the latest. The order of the duration to stay and to feed in the
feeding area was lower-high > high > higher-low > low, and this order did not change under the three different feeding conditions,
“one time feeding,” and the first and second feedings of “two times feeding.” Adolescent females tended to stay the longest
duration in the feeding area among all age classes. Both the lower-high class females and adolescent females had an unstable
social status in the Koshima group, and their social status affected their feeding behaviors. The feeding behaviors were similar
in attitude depending on social status, and are considered to be maintained for a fairly long time.
The feeding strategy of the lower-high class, in staying a longer duration in the artificial feeding area, and departing later,
may be effective under the artificial feeding conditions, but it may be a bad strategy in a natural habitat where the food
is not so clumped as in artificial feeding, and where choice of other food patches is possible. The above results agree well
with previous reports for the Koshima group, indicating that the rank of the lower-high class females was unstable (Mori et al., 1989), and that their reproductive success was low (Watanabe et al., 1992). 相似文献
40.
Bernard Chapais Carole Gauthier Jean Prud’homme 《International journal of primatology》1995,16(3):521-536
It has been proposed that monkeys direct grooming to high-ranking individuals in an attempt to obtain agonistic support in
return. But whether these two categories of interactions are causally related has proven difficult to establish. Part of the
problem stems from the fact that in stable groups social relationships reflect an equilibrium state and that behaviors need
only be performed at low rates and long intervals to maintain the current social structure. In theory, however, if affiliative
and supportive interactions are indeed causally related, it should be possible to accentuate their temporal relation, hence
their causal dynamics. For example, destabilizing dominance relations can be expected to induce competition for status and
force individuals to deploy behavioral tactics for settling new rank relations. We experimentally induced rank reversals in
a captive group of Japanese macaques (Macaca fuscata) composed of three matrilines (A-B-C rank order). A reversed C-A-B order
composed of three individuals per matriline was maintained for 2 weeks. The results show the close temporal relation among
(i) asserting one’s rank, (ii) competing for access to dominants through affiliation and interferences in affiliation, (iii)
receiving support from dominants against lower-ranking individuals, and (iv) supporting dominants against subordinates. These
findings are compatible with one version of the affiliation-for-support hypothesis, namely that monkeys affiliate with dominants
as a way to assert their position in the hierarchy. In a functional perspective, mutual selfishness provides a better explanation
than reciprocal altruism because the possibility that both groomers and supporters derive immediate net benefits cannot be
excluded. 相似文献