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91.
The impact on reproductive success of investigators studying the breeding biology of royal and rockhopper penguins was assessed.
Control and experimental transects were established in a colony of each species and the number of active nests, from egg laying
to creche stage, were compared. Experimental nests were those used in breeding biology work, where birds were measured and
banded, and nest checks were carried out at least once per week. Control nests were in equivalent locations but birds were
not handled, and no contact was made with the nests once breeding had begun. There were no significant differences in the
number of active nests between the control and experimental transects (and, therefore, breeding success) in either species.
It is concluded that, provided care is taken when working with these species, no impacts on the short-term (up to creche stage,
in one breeding season) breeding success of these populations will occur. 相似文献
92.
The survival of unfed males and females of six species of African ticks was monitored at five different saturation deficits at constant temperature (25°C). The survivorship curves for each species comprised a pre-mortality period, prior to when ticks started to die and a mortality period corresponding to a rapid increase in the mortality rate. Longevity was defined as pre-mortality plus mortality. A negative correlation between the longevity of the ticks and the saturation deficits was found with ticks surviving longer at lower deficits. The survival of males and females was similar. At low saturation deficits (2–4 mmHg) Amblyomma hebraeum survived the longest periods (74 weeks). Some correlation was found between the tick survival under dehydrating conditions and habitat associations. Rhipicephalus appendiculatus and Haemaphysalis leachii, the most mesic in distribution, had the shortest longevity (21 and 13 weeks, respectively) at high saturation deficits (7–21 mmHg). Hyalomma marginatum rufipes, the most xerophilic in distribution, had the longest survival (39.3±10.5 weeks) at high saturation deficits. Other factors apart from the adult survival should be taken into account when accounting for the tick distribution, in particular the tolerance of earlier developmental stages to desiccation. 相似文献
93.
Jane Stratford Michael A. Wright Walter Reineke Heiner Mokross Jurgen Havel Christopher J. Knowles Gary K. Robinson 《Archives of microbiology》1996,165(3):213-218
Chlorobenzoates (CBA) arise as intermediates during the degradation of polychlorinated biphenyls (PCBs) and some chlorinated herbicides. Since PCBs were produced as complex mixtures, a range of mono-, di-, and possibly trichloro-substituted benzoates would be formed. Chlorobenzoate degradation has been proposed to be one of the rate-limiting steps in the overall PCB-degradation process. Three hybrid bacteria constructed to have the ability to completely mineralise 2-, 3-, or 4-monochlorobiphenyl respectively, have been studied to establish the range of mono- and diCBAs that can be utilised. The three strains were able to mineralise one or more of the following CBAs: 2-, 3-, and 4-monochlorobenzoate and 3,5-dichlorobenzoate. No utilisation of 2,3-, 2,5-, 2,6-, or 3,4-diCBA was observed, and only a low concentration (0.11 mM) of 2,4-diCBA was mineralised. When the strain with the widest substrate range (Burkholderia cepacia JHR22) was simultaneously supplied with two CBAs, one that it could utilise plus one that it was unable to utilise, inhibitory effects were observed. The utilisation of 2-CBA (2.5 mM) by this strain was inhibited by 2,3-CBA (200 M) and 3,4-CBA (50 M). Although 2,5-CBA and 2,6-CBA were not utilised as carbon sources by strain JHR22, they did not inhibit 2-CBA utilisation at the concentrations studied, whereas 2,4-CBA was co-metabolised with 2-CBA. The utilisation of 2-, 3-, and 4-chlorobiphenyl by strain JHR22 was also inhibited by the presence of 2,3- or 3,4-diCBA. We conclude that the effect of the formation of toxic intermediates is an important consideration when designing remediation strategies.Abbreviations
PCB
Polychlorinated biphenyl
-
CBA
Chlorobenzoate 相似文献
94.
95.
A taxonomic study was recently carried out on the species of Ceramium occurring around Taiwan. One hundred and fifty-one collections were made from January 1993 through spring 1994 at 75 sites distributed around the island. A total of thirteen species were found, including three for which names cannot currently be assigned: Ceramium aduncum, C. ciliatum, C. cimbricum, C. cliftonianum, C. flaccidum, C. gracillimum var. byssoideum, C. mazatlanense, C. nakamurai, C. paniculatum, C. tenerrimum and unidentified species 1, 2 and 3. Among these are three new records for Taiwan, C. cimbricum, C. cliftonianum, and C. mazatlanense. This paper summarizes the taxonomic characters of these species and presents a key for their identification. Distribution records of all 42 species reported from the tropical western Pacific are compared. This report is the first detailed record of the genus for Taiwan. 相似文献
96.
Kazutoyo Osoegawa Rie Susukida Saishi Okano Jun Kudoh Shinsei Minoshima Nobuyoshi Shimizu Pieter J. de Jong Juergen Groet Jane Ives Hans Lehrach Dean Nizetic Eiichi Soeda 《Genomics》1996,32(3):375
The major phenotypic features of Down syndrome have been correlated with partial trisomies of chromosome 21, allowing us to define the candidate gene region to a 4-Mb segment on the 21q22.2 band. We present here a high-resolution physical map with megabase-sized cosmid/PAC contigs. This ordered clone library has provided unique material for the integration of a variety of mappable objects, including exons, cDNAs, restriction sites, etc. Furthermore, our results have exemplified a strategy for the completion of the chromosome 21 map to sequencing. 相似文献
97.
The primary shoot apical meristem of angiosperm plants is formed during embryogenesis. Lateral shoot apical meristems arise postembryonically in the axils of leaves. Recessive mutations at the PINHEAD locus of Arabidopsis interfere with the ability of both the primary shoot apical meristem as well as lateral shoot apical meristems to form. However, adventitious shoot apical meristems can form in pinhead mutant seedlings from the axils of the cotyledons and also from cultred root explants. In this report, the phenotype of pinhead mutants is described, and a hypothesis for the role of the wild-type PINHEAD gene product in shoot meristem initiation is presented. © 1995 Wiley-Liss, Inc. 相似文献
98.
Nathalie Bonnefoy Jane Copsey Michael J. Hynes Mervl A. Davis 《Molecular genetics and genomics : MGG》1995,246(2):223-227
The upstream regulatory region of the amdS gene of Aspergillus nidulans contains a CCAAT sequence known to be important in setting both basal and derepressed levels of expression. We have investigated whether the CCAAT-binding HAP2/3/4 complex of the yeast Saccharomyces cerevisiae can recognise this sequence in an amdS context. Sequences from the 5′ region of amdS were cloned in front of the CYCI-lacZ fusion gene bearing a minimal promoter and transformed into wild-type and hap2 strains of yeast. This study has indicated that amdS sequences are capable of promoting regulated expression of the fusion gene in response to carbon limitation. The yeast HAP2/3/4 complex can recognise the amdS CCAAT sequence and activate expression from this sequence. In addition, the results indicate that other yeast proteins can also regulate expression from the A. nidulans amdS 5′ sequences under carbon-limiting conditions. 相似文献
99.
James R. Brorson Vytautas P. Bindokas Toshi Iwama Charles J. Marcuccilli Jane C. Chisholm Richard J. Miller 《Developmental neurobiology》1995,26(3):325-338
Although a neurotoxic role has been postulated for the β-amyloid protein (βAP), which accumulates in brain tissues in Alzheimer's disease, a precise mechanism underlying this toxicity has not been identified. The peptide fragment consisting of amino acid residues 25 through 35 (βAP25-35), in particular, has been reported to be toxic in cultured neurons. We report that βAP25-35, applied to rat hippocampal neurons in culture, caused reversible and repeatable increases in the intracellular Ca2+ concentration ([Ca2+]i), as measured by fura 2 fluorimetry. Furthermore, βAP25-35 induced bursts of excitatory potentials and action potential firing in individual neurons studied with whole cell current clamp recordings. The βAP25-35–induced [Ca2+]i elevations and electrical activity were enhanced by removal of extracellular Mg2+, and they could be blocked by tetrodotoxin, by non-N-methyl-D -aspartate (NMDA) and NMDA glutamate receptor antagonists, and by the L-type Ca2+ channel antagonist nimodipine. Similar responses of bursts of action potentials and [Ca2+]i increases were evoked by βAP1-40. Responses to βAP25-35 were not prevented by pretreatment with pertussis toxin. Excitatory responses and [Ca2+]i elevations were not observed in cerebellar neuron cultures in which inhibitory synapses predominate. Although the effects of βAP25-35 depended on the activation of glutamatergic synapses, there was no enhancement of kainate- or NMDA-induced currents by βAP25-35 in voltage-clamp studies. We conclude that βAP25-35 enhances excitatory activity in glutamatergic synaptic networks, causing excitatory potentials and Ca2+ influx. This property may explain the toxicity of βAP25–35. © 1995 John Wiley & Sons, Inc. 相似文献
100.
Hillard S. Kaplan Jane B. Lancaster Sara E. Johnson John A. Bock 《Human nature (Hawthorne, N.Y.)》1995,6(4):325-360
Our objective is to test an optimality model of human fertility that specifies the behavioral requirements for fitness maximization
in order (a) to determine whether current behavior does maximize fitness and, if not, (b) to use the specific nature of the behavioral deviations from fitness maximization towards the development of models of evolved
proximate mechanisms that may have maximized fitness in the past but lead to deviations under present conditions. To test
the model we use data from a representative sample of 7,107 men living in Albuquerque, New Mexico, between 1990 and 1993.
The model we test proposes that low fertility in modern settings maximizes number of grandchildren as a result of a trade-off
between parental fertility and next generation fertility. Results do not show the optimization, although the data do reveal
a trade-off between parental fertility and offspring education and income.
We propose that two characteristics of modern economies have led to a period of sustained fertility reduction and to a corresponding
lack of association between income and fertility. The first is the direct link between costs of investment and wage rates
due to the forces of supply and demand for labor in competitive economies. The second is the increasing emphasis on cumulative
knowledge, skills, and technologies in the production of resources. Together they produce historically novel conditions. These
two features of modern economies may interact with evolved psychological and physiological mechanisms governing fertility
and parental investment to produce behavior that maximizes the economic productivity of lineages at the expense of fitness.
If cognitive processes evolved to track diminishing returns to parental investment and if physiological processes evolved
to regulate fertility in response to nutritional state and patterns of breast feeding, we might expect non-adaptive responses
when returns from parental investment do not diminish until extremely high levels are reached. With high economic payoffs
from parental investment, people have begun to exercise cognitive regulation of fertility through contraception and family
planning practices. Those cognitive processes maynot have evolved to handle fitness trade-offs between fertility and parental investment.
A preliminary presentation of this data was published in R. I. M. Dunbar, ed.,Human Reproduction Decisions: Biological and Social Perspectives. New York: St. Martin’s Press, 1995. Support for the research project, “Male Fertility and Parenting in New Mexico,” began
with two seed grants from the University of New Mexico’s Biomedical Research Grants Program, 1988 and 1989, and one from the
University of New Mexico Research Allocations Committee, 1988. Further seed money as well as interim funding came from the
William T. Grant Foundation (#89130589 and #91130501). The major support for the project came from the National Science Foundation
from 1990 to 1993 (#BNS-9011723 and #DBS-911552). Both National Science Foundation grants included Research Experience for
Undergraduates supplements.
Hillard S. Kaplan is an Associate Professor of Anthropology at the University of New Mexico. His earlier research and publications
focused on food sharing, time allocation, parental investment, and reproductive strategies among Ache hunter-gatherers in
Paraguay, Machiguenga and Piro forager-horticulturalists in Peru, and villagers of several ethnicities in Botswana. New research
and theory concern fertility, parental investment, and mating strategies in developed and developing nations. This research
formulates a new theory of reproductive decision-making and the demographic transition, integrating human capital and parental
investment theory in a synthesis of economic and evolutionary approaches.
Jane B. Lancaster is a Professor of Anthropology at the University of New Mexico. Her research and publications are on human
reproductive biology and behavior, especially human parental investment; women’s reproductive biology of pregnancy, lactation,
and child-spacing; and male fertility and investment in children. Current research with Hillard S. Kaplan is on male life
history strategies among a large sample of men in New Mexico. She has coedited three books on human parental investment:School-Age Pregnancy and Parenthood (with B. Hamburg),Parenting across the Life Span (with J. Altmann, A. Rossi, and L. Sherrod), andOffspring Abuse and Neglect (with R. Gelles). She is scientific editor of a quarterly journal,Human Nature: An Interdisciplinary, Biosocial Perspective published by Aldine de Gruyter. She is also a council member of the newly formed Human Behavior and Evolution Society.
John A. Bock is Andrew W. Mellon Post-Doctoral Fellow in Epidemiology and Population Health at the National Centre for Epidemiology
and Population Health, The Australian National University. His research focuses on the allocation of parental investment and
the determinants of children’s activities, integrating aspects of economic and evolutionary theory. He has ongoing field research
with Bantu and Bushmen agro-pastoralists and forager-horticulturalists in the Okavango Delta, Botswana. He is also collaborating
with Lancaster and Kaplan on the determinants of progeny distribution and homosexuality among New Mexican men.
Sara E. Johnson is a Ph.D. candidate at the University of New Mexico. Her major research trajectory focuses on trade-offs
in life history characters. Her research experience includes participation in a study of variation in growth and development
among children in a multi-ethnic community in the Okavango Delta, Botswana, in addition to her dissertation work on individual
variation in growth and mortality among juvenile baboons. She is collaborating with Lancaster and Kaplan on the association
between survival and fertility among Albuquerque men. 相似文献