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81.
JOSEPH S. ALTER 《American anthropologist》2006,108(3):549-550
Female Ascetics in Hinduism. Lynn Teskey Denton. Albany: State University of New York Press, 2004. 218 pp.
The Graceful Guru: Hindu Female Gurus in India and the United States. Karen Pechilis, ed. Oxford: Oxford University Press, 2004. 260 pp.
Offering Flowers, Feeding Skulls: Popular Goddess Worship in West Bengal. June McDaniel. Oxford and New York: Oxford University Press, 2004. 356 pp. 相似文献
The Graceful Guru: Hindu Female Gurus in India and the United States. Karen Pechilis, ed. Oxford: Oxford University Press, 2004. 260 pp.
Offering Flowers, Feeding Skulls: Popular Goddess Worship in West Bengal. June McDaniel. Oxford and New York: Oxford University Press, 2004. 356 pp. 相似文献
82.
Australian Magpies Gymnorhina tibicen sometimes attack and kill other birds in New Zealand. Here we assess how Australian Magpies influence the local distribution of other birds in New Zealand and identify the members of an Australian Magpie population that display the most agonistic acts. We conducted regular observations on six territorial breeding groups and three non‐breeding flocks of Australian Magpies for 1 year to determine (1) if other birds avoid flying or foraging close to Australian Magpies, (2) the proportion of passing birds that are attacked and (3) which social subunits of the Australian Magpie population are most aggressive. In comparison with adjacent Magpie‐free control areas, significantly fewer birds of a range of species (e.g. Common Blackbird Turdus merula, Skylark Alauda arvensis, Yellowhammer Emberiza citrinella) foraged close (i.e. ≤ 50 m) to both territorial breeding groups and non‐breeding Australian Magpie flocks; fewer birds were also recorded flying near (i.e. ≤ 50 m) territorial breeding groups but not non‐breeding flocks. Excluding Australasian Harriers (Circus approximans: see below), only 8% of birds recorded within 50 m of territorial breeding groups were observed being attacked. Attacks were most frequent when numerous birds occurred near Australian Magpies and species recorded in the highest frequencies were generally attacked most. Territorial breeding groups attacked 39% of passing Australasian Harriers. All attacks consisted of the victim being swooped at or chased; no physical contact was ever observed. Both adult male and female breeding Australian Magpies were seen attacking other birds; juveniles in breeding groups sometimes supported adults but never initiated attacks. Australian Magpies in non‐breeding flocks were not seen attacking other birds, except Australasian Harriers (attacked in 17% of appearances). Our results suggest that some birds avoid foraging and/or flying close to Australian Magpies because they are sometimes chased by breeding adults of both sexes; however, the proportion of passing birds actually attacked was small. The numerous published observations of Australian Magpie attacks are apparently biased heavily towards sensational events that are rare. Possible reasons why Australian Magpies attack other birds are discussed. 相似文献
83.
JOSEPH D. CONROY WILLIAM J. EDWARDS RUTH A. PONTIUS DOUGLAS D. KANE HONGYAN ZHANG JOHN F. SHEA JULIE N. RICHEY DAVID A. CULVER 《Freshwater Biology》2005,50(7):1146-1162
1. Recent increases in phytoplankton biomass and the recurrence of cyanobacterial blooms in western Lake Erie, concomitant with a shift from a community dominated by zebra mussels (Dreissena polymorpha) to one dominated by quagga mussels (D. bugensis), led us to test for differences in ammonia‐nitrogen and phosphate‐phosphorus excretion rates of these two species of invasive molluscs. 2. We found significant differences in excretion rate both between size classes within a taxon and between taxa, with zebra mussels generally having greater nutrient excretion rates than quagga mussels. Combining measured excretion rates with measurements of mussel soft‐tissue dry weight and shell length, we developed nutrient excretion equations allowing estimation of nutrient excretion by dreissenids. 3. Comparing dreissenid ammonia and phosphate excretion with that of the crustacean zooplankton, we demonstrated that the mussels add to nitrogen and phosphorus remineralisation, shortening nitrogen and phosphorus turnover times, and, importantly, modify the nitrogen and phosphorus cycles in Lake Erie. The increased nutrient flux from dreissenids may facilitate phytoplankton growth and cyanobacterial blooms in well‐mixed and/or shallow areas of western Lake Erie. 相似文献
84.
JOSEPH ATABEKOV EUGEN DOBROV OLGA KARPOVA NINA RODIONOVA 《Molecular Plant Pathology》2007,8(5):667-675
This paper summarizes some structural characteristics of Potato virus X (PVX), the flexuous filamentous plant potexvirus. A model of PVX coat protein (CP) tertiary structure in the virion proposed on the basis of tritium planigraphy combined with predictions of the protein tertiary structure is described. A possible role of glycosylation and phosphorylation in the CP structure and function is discussed. Two forms of PVX virion disassembly are discussed: (i) the virion co-translational disassembly after PVX CP in situ phosphorylation and (ii) disassembly of PVX triggered by different factors after linear destabilization of the virion by binding of the PVX-coded movement protein (TGBp1) to one end of the polar CP-helix. Special emphasis was placed on a translational activation of encapsidated PVX RNA and rapid disassembly of TGBp1-PVX complexes into free RNA and CP. The results of experiments on the PVX CP repolymerization and PVX reconstitution are considered. In particular, the products assembled from PVX RNA, CP and TGBp1 were examined. Single-tailed particles were found with a helical, head-like structure consisting of helically arranged CP subunits located at the 5'-tail of RNA; the TGBp1 was bound to the end of the head. Translatable 'RNA-CP-TGBp1' complexes may represent the transport form of the PVX infection. 相似文献
85.
COLICINOGENIC factor E1 (Col E1) is a small bacterial plasmid (4.2×106 daltons) present in colicinogenic strains of Escherichia coli1 to the extent of about twenty-four copies per cell (Clewell and Helinski, unpublished results), which continues to replicate in the presence of high levels of chloramphenicol, a specific inhibitor of protein synthesis, although the chromosome only completes current rounds of replication and ceases (Clewell and Helinski, unpublished results). The average rate of Col E1 semiconservative replication in the absence of protein synthesis is, in certain conditions, faster than (as much as eight times) the normal rate of synthesis (Clewell, unpublished results). Replication continues for 10–15 h after the addition of chloramphenicol, resulting in nearly 3,000 copies of Col E1 DNA per cell. We are taking advantage of this system to study the effects of a number of antibiotics on DNA replication and now report evidence that rifampicin (an active semisynthetic derivative of rifamycin B)2, an antibiotic known specifically to inhibit bacterial DNA dependent RNA polymerase3–6, has a dramatic inhibitory effect on Col E1 DNA replication. 相似文献
86.
NAVAL J. ANTIA RICHARD F. LEE JUDD C. NEVENZEL JOSEPH Y. CHENG 《The Journal of eukaryotic microbiology》1974,21(5):768-771
SYNOPSIS. An age-autolyzed culture of Chroomonas salina , grown under cool-white light with glycerol, produced waxy lipid constituting about 44% of total matter harvested. This lipid was composed of 87% wax ester, 9% triglyceride, 3% polar lipid and 1% hydrocarbon. The major wax ester species were identified by total carbon number as C26 (28%), C28 (35%), C30 (15%). The main fatty acid components of the wax esters were 12:0 (39%), 14:0 (30%), 16:0 (14%), while the main alcohols were 14:0 (53%) and 16:0 (40%). The hydrocarbon fraction showed saturated paraffins ranging from C17 to C33 , with odd-numbered chain components predominating. No polyunsaturated components were detected in the wax ester or hydrocarbon fractions. This is the first record of wax ester production by a cryptomonad or a marine phytoplankter. 相似文献
87.
88.
水螅(Hydra oligactus Pallus)之觸手數目,在天然環境中,可以有自十個至五個之差異。早期之研究皆以為觸手數目之决定皆由于水螅之大小及年齡。但實際觀察中有二點,顯示觸手數目似與水螅之大小無關:(1)此二者之間之相關係數極低,(2)水螅在生長條件最優時,可以增加其體積之大小,而觸手之數目不增多。但在某種環境下,水螅之觸手確能增加。此種環境之一即為華氏五十五度左右之温度。在該情形下,出芽生殖率降低,而觸手可以長出。此一情形,在自然間,即為晚晚春及早秋之温度。故水螅經年後,可以增加觸手之數目,亦可謂,觸手數目舆水螅之年齡有關。觸手增多無一定之規則。平常皆增加一至二觸手。但有時亦可增加一圈觸手(四個至五個)。水螅觸手數目正常或係六個,最少為三個,最多為十二個。但此二情形之水螅曾不能存在長久。三個觸手之水螅不久即長出第四個觸手,十二個觸手之水螅則不久即縱裂為二個水螅。 相似文献
89.
NELSON A. MEDEIROS THOMAS S. REESE HOWARD JAFFE JOSEPH A. DEGIORGIS ELAINE L. BEARER 《Cell biology international》1998,22(2):161-173
The squid giant axon provides an excellent model system for the study of actin-based organelle transport likely to be mediated by myosins, but the identification of these motors has proven to be difficult. Here the authors purified and obtained primary peptide sequence of squid muscle myosin as a first step in a strategy designed to identify myosins in the squid nervous system. Limited digestion yielded fourteen peptides derived from the muscle myosin which possess high amino acid sequence identities to myosin II from scallop (60–95%) and chick pectoralis muscle (31–83%). Antibodies generated to this purified muscle myosin were used to isolate a potential myosin from squid optic lobe which yielded 11 peptide fragments. Sequences from six of these fragments identified this protein as a myosin II. The other five sequences matched myosin II (50–60%, identities), and some also matched unconventional myosins (33–50%). A single band that has a molecular weight similar to the myosin purified from optic lobe copurifies with axoplasmic organelles, and, like the optic lobe myosin, this band is also recognized by the antibodies raised against squid muscle myosin II. Hence, this strategy provides an approach to the identification of a myosin associated with motile axoplasmic organelles. 相似文献
90.
Evolutionary implications of hierarchical impacts of nonlethal injury on reproduction, including maternal effects 总被引:2,自引:0,他引:2
JOSEPH BERNARDO SALVATORE J. AGOSTA 《Biological journal of the Linnean Society. Linnean Society of London》2005,86(3):309-331
Nonlethal injury is pervasive in metazoans, but surprisingly little is known about its impact upon reproductive allocation. The impact of injury on reproduction has been explored in some detail in lizards and salamanders, which have tails that are adapted for fat storage but are also injured or lost during predatory and social encounters. We synthesize diverse insights from these studies and propose new hypotheses using graphical models which highlight three distinct, hierarchical effects of injury on reproduction: reproductive inhibition, reduction in propagule number and diminished per‐propagule investment (PPI), a maternal effect. Previous studies, which involved experimentally amputating the whole tail, have provided evidence of the first two effects, although there is little evidence of reduced PPI. We assayed these effects in free‐ranging Desmognathus salamanders exhibiting naturally occurring injury. Whereas earlier studies found that tail injury prohibits reproduction (precipitating functional conflict), we found that females missing 80% of their tails, including the smallest mature individuals, still reproduce. We also detected a negative correlation between magnitude of injury and PPI, a continuous maternal effect. Continuous (graded) effects of injury on PPI have not been reported previously; neither discrete nor continuous maternal effects due to injury have been previously demonstrated in free‐ranging vertebrates. The dearth of evidence for such effects may be due to the design of experimental manipulations that use all‐or‐nothing treatments. Future studies employing quantitative field data, or more realistic experimental treatments that mimic the continuous distribution of injury are likely to detect maternal effects arising from nonlethal injury. Although our comparative and empirical findings derive from studies of lizards and salamanders, we discuss how they apply in principle to all metazoans. Studies of these effects in nonvertebrate model systems are sorely needed. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 309–331. 相似文献