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101.
John S. Adams Mercedes A. Gacad Andrew J. Baker Benjamin Gonzales Robert K. Rude 《American journal of primatology》1985,9(3):219-224
We measured the serum concentration of 25-hydroxyvitamin D3 (25-OH-D3) and 1,25-dihydroxyvitamin D3 (1,25-[OH]2-D3) in 23 different Platyrrhines from four different genera and in 21 Catarrhines from six different genera in residence at the Los Angeles Zoo. The mean (±S.E.) serum concentration of 1,25-(OH)2-D3 was significantly greater in Platyrrhines (810 ± 119 pg/ml) than in Catarrhines (61 ± 5 pg/ml), suggesting that high circulating concentrations of the active vitamin D hormone were a characteristic of New World primates in both the Cebidae and Callitrichidae family. This increase in the serum concentration of 1,25-(OH)2-D3 is probably an adaptational response on the part of Platyrrhini to offset a relative decrease in the concentration of specific receptor for 1,25-(OH)2-D3 in target tissues for the hormone. 相似文献
102.
Population dynamics, rate of root penetration, and external root feeding behavior of Pratylenchus agilis (Pa) in monoxenic cultures of intact corn seedlings and root explants of corn, tomato, and soybean were studied. In descending order of suitability as hosts were I. O. Chief corn, Rutgers tomato, and Williams soybean. Soybean entries Kent, Pickett 71, PI 90763, and Essex were poor hosts. Numbers of eggs and vermiform Pa in the agar medium indicated total fecundity and host suitability. Agar, sand, or soil as support media did not appear to affect Pa root penetration, but the rate of corn root growth did. Whereas most vermiform Pa and eggs were in roots, substantial numbers appeared able to feed and complete their life cycle as ectoparasites on root epidermal cells and root hairs. 相似文献
103.
Food rewards were given contingent upon the performance of one of three natural responses in adult male pigtail macaques:
scratching, yawning, and the facial expression “protruded lips.” Scratching rapidly increased in frequency when it was followed
by food, as did variability in form of scratching and one form in particular, using the feet. The facial expression was resistant
to the conditioning procedures. Yawning increased in frequency when followed by food, with extinction and reconditioning procedures
confirming the establishment of the conditioned response. This is the first report of the conditioning of yawning in primates.
Together, the results contribute to the literature on the differential conditionability of different classes of behavior,
and suggest the possibility that macaques can voluntarily display “reflexive” acts for social goals. 相似文献
104.
Hans-Jürgen Hahn Erik Gylfe Bo Hellman 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,630(3):425-432
The effect of cyclic AMP on calcium movements in the pancreatic β-cell was evaluated using an experimental approach based on in situ labelling of intracellular organelles of ob/ob-mouse islets with 45Ca. Whereas the glucose-stimulated 45Ca incorporation by mitochondria and secretory granules was increased under a condition known to reduce cyclic AMP (starvation), raised levels of this nucleotide (addition of 3-isobutyl-1-methylxanthine or N6,O2′-dibutyryl adenosine 3′,5′-cyclic monophosphate) reduced the mitochondrial accumulation of 45Ca. Conditions with increased cyclic AMP were associated with a stimulated efflux of 45Ca from the secretory granules but not from the mitochondria. The microsomal fraction differed from both the mitochondrial and secretory granule fractions by accumulating more 45Ca after the addition of 3-isobutyl-1-methylxanthine. The results suggest that cyclic AMP potentiates glucose-stimulated insulin release by increasing cytoplasmic Ca2+ at the expense of the calcium taken up by the organelles of the pancreatic β-cells. 相似文献
105.
106.
Thomas E. Ruehlmann Irwin S. Bernstein Thomas P. Gordon Peter Balcaen 《American journal of primatology》1988,14(2):125-134
The incidence of wounding in captive groups of rhesus (Macaca mulatta), pigtail (M. nemestrina), and stumptail (M. arctoides) macaques was studied for 21 months. Groups were monitored daily for evidence of wounding. Wounded animals were captured, treated by veterinary staff, and returned following recovery. Records were kept on the age, sex, and species of the recipient, along with the type and location of wound. In each species of macaque, adult males incurred the highest frequency of wounds and multiple wounds of any age-sex class. This contrasted with previously reported behavioral data indicating low frequencies of aggression received by adult males, especially contact aggression and bites. These discrepancies indicate wounding frequencies do not necessarily correspond with behavioral measures of aggression. Inhibition of aggression directed toward infants and the selective avoidance of bites directed to vital body regions were presented as possible mechanisms that modify intragroup aggression. Increased wounding in the birth season under captive conditions suggests that the pattern of increased wounding reported during the breeding season under freeranging conditions may reflect xenophobic responses to immigrating males, rather than direct male-male competition for estrous females. 相似文献
107.
108.
Takashi Arakawa Yoshiaki Kamiya 《Biochemical and biophysical research communications》2010,397(2):345-349
We previously reported the identification of DP-1 isoforms (α and β), which are structurally C-terminus-deleted ones, and revealed the low-level expression of these isoforms. It is known that wild-type DP-1 is degraded by the ubiquitin-proteasome system, but few details are known about the domains concerned with the protein stability/instability for the proteolysis of these DP-1 isoforms. Here we identified the domains responsible for the stability/instability of DP-1. Especially, the DP-1 “Stabilon” domain was a C-terminal acidic motif and was quite important for DP-1 stability. Moreover, we propose that this DP-1 Stabilon may be useful for the stability of other nuclear proteins when fused to them. 相似文献
109.
Inflammatory responses mediated by activated microglia play a pivotal role in the pathogenesis of human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders. Studies on identification of specific targets to control microglia activation and resultant neurotoxic activity are imperative. Increasing evidence indicate that voltage-gated K+ (Kv) channels are involved in the regulation of microglia functionality. In this study, we investigated Kv1.3 channels in the regulation of neurotoxic activity mediated by HIV-1 glycoprotein 120 (gp120)-stimulated rat microglia. Our results showed treatment of microglia with gp120 increased the expression levels of Kv1.3 mRNA and protein. In parallel, whole-cell patch-clamp studies revealed that gp120 enhanced microglia Kv1.3 current, which was blocked by margatoxin, a Kv1.3 blocker. The association of gp120 enhancement of Kv1.3 current with microglia neurotoxicity was demonstrated by experimental results that blocking microglia Kv1.3 attenuated gp120-associated microglia production of neurotoxins and neurotoxicity. Knockdown of Kv1.3 gene by transfection of microglia with Kv1.3-siRNA abrogated gp120-associated microglia neurotoxic activity. Further investigation unraveled an involvement of p38 MAPK in gp120 enhancement of microglia Kv1.3 expression and resultant neurotoxic activity. These results suggest not only a role Kv1.3 may have in gp120-associated microglia neurotoxic activity, but also a potential target for the development of therapeutic strategies. 相似文献
110.
During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis. 相似文献