共查询到20条相似文献,搜索用时 15 毫秒
1.
Indra K. Vasil 《In vitro cellular & developmental biology. Plant》2008,44(5):365-372
The International Association for Plant Biotechnology (IAPB) was founded in 1963 at the first truly international conference
on plant tissue culture, which was organized by Philip R. White. White was a devoted internationalist and was strongly committed
to global scientific cooperation. He felt that the time had come for the international tissue culture community to organize
so that it could meet regularly and provide a forum to its members for the exchange of ideas and information of mutual interest
and use. The various activities of the IAPB since its founding—the publication of its newsletter, its journal, and the proceedings
of its quadrennial congresses—faithfully document the remarkable advances in plant biotechnology that were made possible by
the successful integration of tissue culture and molecular biology. In particular, the congress proceedings serve as time
capsules, providing a wealth of information about the best of science and the most prominent scientists of the time. The history
of the IAPB is indeed the history of plant biotechnology. 相似文献
2.
《Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences》2002,33(3):489-513
Despite a long tradition of research in applied genetics, particularly in agricultural research, in Italy the transition to the new knowledges and techniques of molecular biology was long and difficult. Political and financial constraints made academic institutions very slow to grasp the importance of molecular approaches to biology and medicine. In fact, the main studies concerning problems of molecular biology took place inside non-academic institutions. We reconstruct the complex paths leading to the birth of the International Laboratory of Genetics and Biophysics (LIGB) in Naples, and describe its work and activities in the period in which it was directed by its creator, Adriano Buzzati-Traverso, between 1962 and 1969. The origins of the LIGB are inextricably bound to the growth of biophysical research at the University of Pavia and at the Higher Health Institute in Rome. For a short period, with the aid provided by Italian and European physicists to biological research on the effects of nuclear radiation, LIGB became a focal point in European molecular biology. In 1968 the scientific and educational activities of the LIGB dramatically fell victim to the contradictions of the Italian academic and scientific system, and to the political climate which emerged in Italy at the time. 相似文献
3.
Jeffrey M. Roseman 《人类与生态风险评估》1998,4(3):737-746
Epidemiologic studies can play a central role in risk assessments. They are used in all risk assessment phases: hazard identification, dose-response, and exposure assessment. Epidemiologic studies have often been the first to show that a particular environmental exposure is a hazard to health. They have numerous advantages with respect to other sources of data which are used in risk assessments, the most important being that they do not require the assumption that they are generalizable to humans. For this reason, fewer and lower uncertainty factors may be appropriate in risk characterization based on epidemiologic studies. Unfortunately, epidemiologic studies have numerous problems, the most important being that the exposures are often not precisely measured. This article presents in detail the advantages of and problems with epidemiologic studies. It discusses two approaches to ensure their usefulness, biomarkers and an ordinance which requires baseline and subsequent surveillance of possible exposures and health effects from newly sited potentially polluting facilities. Biomarkers are biochemical measures of exposure, susceptibility factors, or preclinical pathological changes. Biomarkers are a way of dealing with the problems of poor measures, differential susceptibility and lack of early measures of disease occurrence that inherent in many environmental epidemiologic studies. The advantages of biomarkers is they can provide objective information on exposure days, months or even years later and evidence of pathology perhaps years earlier. The ordinance makes possible the use of a powerful epidemiologic study design, the prospective cohort study, where confounder(s) are best measured, and exposures, pathological changes, and health effects can be detected as soon as possible. 相似文献
4.
Connor Sheehan Jennifer Karas Montez Isaac Sasson 《Biodemography and social biology》2018,64(1):63-81
To understand the education–mortality association among U.S. adults, recent studies have documented its national functional form. However, the functional form of education–mortality relationship may vary across geographic contexts. The four U.S. Census regions differ considerably in their social and economic policies, employment opportunities, income levels, and other factors that may affect how education lowers the risk of mortality. Thus, we documented regional differences in the functional form of the education–mortality association and examined the role of employment and income in accounting for regional differences. We used data on non-Hispanic white adults (2,981,672, person years) aged 45–84 in the 2000–2009 National Health Interview Survey, with Linked Mortality File through 2011 (37,598 deaths) and estimated discrete-time hazard models. The functional form of education and adult mortality was best characterized by credentialism in the Midwest, Northeast, and for Western men. For Western women, the association was linear, consistent with the human capital model. In the South, we observed a combination of mechanisms, with mortality risk declining with each year of schooling and a step change with high school graduation, followed by steeper decline thereafter. Our work adds to the increasing body of research that stresses the importance of contexts in shaping the education–mortality relationship. 相似文献
5.
Tom P. Moorhouse Cecilia A. L. Dahlsj? Sandra E. Baker Neil C. D'Cruze David W. Macdonald 《PloS one》2015,10(10)
Tourism accounts for 9% of global GDP and comprises 1.1 billion tourist arrivals per annum. Visits to wildlife tourist attractions (WTAs) may account for 20–40% of global tourism, but no studies have audited the diversity of WTAs and their impacts on the conservation status and welfare of subject animals. We scored these impacts for 24 types of WTA, visited by 3.6–6 million tourists per year, and compared our scores to tourists’ feedback on TripAdvisor. Six WTA types (impacting 1,500–13,000 individual animals) had net positive conservation/welfare impacts, but 14 (120,000–340,000 individuals) had negative conservation impacts and 18 (230,000–550,000 individuals) had negative welfare impacts. Despite these figures only 7.8% of all tourist feedback on these WTAs was negative due to conservation/welfare concerns. We demonstrate that WTAs have substantial negative effects that are unrecognised by the majority of tourists, suggesting an urgent need for tourist education and regulation of WTAs worldwide. 相似文献
6.
Raelene A. Giffney Darrell J. Kemp 《Ethology : formerly Zeitschrift fur Tierpsychologie》2014,120(6):607-615
Knowledge of the selective pressures favouring parental care can inform our understanding of the evolutionary origins and transitions of sociality in insects. Here, we report upon investigations designed to estimate the costs and benefits of parental care in the egg‐guarding hibiscus harlequin bug Tectocoris diophthalmus (Heteroptera: Scutelleridae). We found that the presence of a guarding female had no effect on hatching success under benign laboratory conditions. In the wild, however, guarding decreased the likelihood of total clutch failure, and produced a fourfold greater egg‐hatching rate relative to unguarded clutches. Females guarded against generalist invertebrate egg predators, including conspecific nymphs, but were ineffective against hymenopteran egg parasitoids. Females continued to feed during the guarding period and exhibited no signs of weight loss or increased mortality due to this behaviour. We did not observe the production of subsequent clutches in any experimental females; therefore, the lifetime fecundity costs of providing parental care in T. diophthalmus remain indeterminate. Overall, maternal egg guarding appears to function as a relatively low cost–low benefit strategy that increases hatching success by protecting against predation – but not parasitism. 相似文献
7.
Background
Animals captive bred for reintroduction are often housed under conditions which are not representative of their preferred social structure for at least part of the reintroduction process. Specifically, this is most likely to occur during the final stages of the release programme, whilst being housed during transportation to the release site. The degree of social stress experienced by individuals during this time may negatively impact upon their immunocompetence.Methodology/Principal Findings
We examined two measure of stress - body weight and Leukocyte Coping Capacity (LCC) - to investigate the effects of group size upon captive-bred water voles destined for release within a reintroduction program. Water voles were housed in laboratory cages containing between one and eight individuals. LCC scores were negatively correlated with group size, suggesting that individuals in larger groups experienced a larger degree of immuno-suppression than did individuals housed in smaller groups or individually. During the course of the study mean body weights increased, in contrast to expectations from a previous study. This was attributed to the individuals sampled being sub-adults and thus growing in length and weight during the course of the investigation.Conclusions/Significance
The reintroduction process will inevitably cause some stress to the release cohort. However, for water voles we conclude that the stress experienced may be reduced by decreasing group size within captive colony and/or transportation housing practises. These findings are of significance to other species'' reintroductions, in highlighting the need to consider life-history strategies when choosing housing systems for animals being maintained in captivity prior to release to the wild. A reduction in stress experienced at the pre-release stage may improve immunocompetence and thus animal welfare and initial survival post-release. 相似文献8.
9.
It has been shown in a previous paper (8) that the prime product of reassociation of related DNA sequences under open experimental conditions are mismatched duplexes which undergo maturation upon further incubation. Due to this feature, the Tm value of the duplexes of a large number of DNAs is strongly dependent on the Cot value. Here we present data showing that the Tm of the duplexes of such type of DNAs depends also on the concentration of DNA in the range of one and the same Cot value. The significance of this finding in studying the taxonomic relationship by DNA-DNA hybridisation is discussed.Abbreviations Co =
initial concentration of single-stranded DNA in moles of nucleotides per liter
- t =
time of incubation in seconds
- Cot =
the product of Co and t (mol. sec. 11)
- PB =
an equimolar mixture of NaH2PO4 and Na2HPO4, pH 6.8
- HAP =
hydroxyapatite
- Ti =
incubation temperature
- Tm =
melting temperature
- Te =
elution temperature, i.e. the temperature at which one half of the DNA is eluted as single strands by HAP-thermal chromatography 相似文献
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11.
Vuosku J Jaakola L Jokipii S Karppinen K Kämäräinen T Pelkonen VP Jokela A Sarjala T Hohtola A Häggman H 《Molecular biotechnology》2004,27(3):209-215
An automated nucleic acid extraction procedure with magnetic particles originally designed for isolation of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) from animal tissues was tested for plant material. We isolated genomic DNA and total RNA from taxonomically diverse plant species representing conifers (Scots pine), broad-leaved trees (silver birch and hybrid aspen), dwarf shrubs (bilberry), and both monocotyledonous (regal lily) and dicotyledonous (Saint John's wort, round-leaved sundew, and tobacco) herbaceous plants. Buffers developed for DNA extraction were successfully used in addition to manufacturer's extraction kits. The quality of RNA was appropriate for many applications, but the quality of DNA was not always sufficient for polymerase chain reaction (PCR) amplification. However, we could strikingly improve the quality by eliminating the adherent compounds during the extraction or later in the PCR phase. Our results show that the use of the procedure could be extended to diverse plant species. This procedure is especially suitable for small sample sizes and for simultaneous processing of many samples enabling large-scale plant applications in population genetics, or in the screening of putative transgenic plants. 相似文献
12.
Welch V Petticrew M Ueffing E Benkhalti Jandu M Brand K Dhaliwal B Kristjansson E Smylie J Wells GA Tugwell P 《PloS one》2012,7(3):e31360
Introduction
Tackling health inequities both within and between countries remains high on the agenda of international organizations including the World Health Organization and local, regional and national governments. Systematic reviews can be a useful tool to assess effects on equity in health status because they include studies conducted in a variety of settings and populations. This study aims to describe the extent to which the impacts of health interventions on equity in health status are considered in systematic reviews, describe methods used, and assess the implications of their equity related findings for policy, practice and research.Methods
We conducted a methodology study of equity assessment in systematic reviews. Two independent reviewers extracted information on the reporting and analysis of impacts of health interventions on equity in health status in a group of 300 systematic reviews collected from all systematic reviews indexed in one month of MEDLINE, using a pre-tested data collection form. Any differences in data extraction were resolved by discussion.Results
Of the 300 systematic reviews, 224 assessed the effectiveness of interventions on health outcomes. Of these 224 reviews, 29 systematic reviews assessed effects on equity in health status using subgroup analysis or targeted analyses of vulnerable populations. Of these, seven conducted subgroup analyses related to health equity which were reported in insufficient detail to judge their credibility. Of these 29 reviews, 18 described implications for policy and practice based on assessment of effects on health equity.Conclusion
The quality and completeness of reporting should be enhanced as a priority, because without this policymakers and practitioners will continue lack the evidence base they need to inform decision-making about health inequity. Furthermore, there is a need to develop methods to systematically consider impacts on equity in health status that is currently lacking in systematic reviews. 相似文献13.
Leigh EG Vermeij GJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2002,357(1421):709-718
Three types of evidence suggest that natural ecosystems are organized for high productivity and diversity: (i) changes not previously experienced by a natural ecosystem, such as novel human disturbances, tend to diminish its productivity and/or diversity, just as 'random' changes in a machine designed for a function usually impair its execution of that function; (ii) humans strive to recreate properties of natural ecosystems to enhance productivity of artificial ones, as farmers try to recreate properties of natural soils in their fields; and (iii) productivity and diversity have increased during the Earth's history as a whole, and after every major biotic crisis. Natural selection results in ecosystems organized to maintain high productivity of organic matter and diversity of species, just as competition among individuals in Adam Smith's ideal economy favours high production of wealth and diversity of occupations. In nature, poorly exploited energy attracts more efficient users. This circumstance favours the opening of new ways of life and more efficient recycling of resources, and eliminates most productivity-reducing 'ecological monopolies'. Ecological dominants tend to be replaced by successors with higher metabolism, which respond to more stimuli and engage in more varied interactions. Finally, increasingly efficient predators and herbivores favour faster turnover of resources. 相似文献
14.
Skadhauge E Erlwanger KH Ruziwa SD Dantzer V Elbrønd VS Chamunorwa JP 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,134(4):749-755
The ostrich is unique among birds in having complete separation of urine and faeces. The coprodeal epithelium is thus during dehydration exposed to a fluid 500 mOsm hyperosmotic to plasma. We have investigated whether the coprodeum is adapted like a mammalian bladder. The coprodeal epithelium was studied by electrophysiology in the Ussing chamber, and the anatomy by light microscopy and scanning electron microscopy. ELECTROPHYSIOLOGY: The short-circuit current (SCC) and open circuit electrical potential difference were recorded. The change induced by 0.1 mmol mucosal amiloride was recorded. An average basal SCC of 162+/-29 microA/cm(2) was observed, and a resistance of 297+/-34 Omega cm(2) calculated. These values are as observed in other avian coprodea. The resistance is much lower than in mammalian bladders (10000 Omega cm(2)). The amiloride-sensitive SCC, equal to net sodium absorption, was approximately 5 micromol/cm(2)h as observed in other avian species. ANATOMY: The mucosal membrane is composed of broad irregular folds with very short intestinal glands containing an unusually high proportion of goblet cells. CONCLUSION: The ostrich coprodeum is not adapted like a mammalian bladder. The abundance of goblet cells results in a copious secretion of mucus that establishes a thick unstirred layer giving effective osmotic protection. 相似文献
15.
A A Ne?fakh 《Ontogenez》1985,16(1):15-25
Two closely related controversial problems are discussed: whether the developmental processes can be reduced to the synthesis of polypeptides encoded in DNA, and whether the information in DNA is equivalent to that in the adult organism. Critically considered are the ideas that DNA is only responsible for the protein synthesis, whereas morphogenesis proceeds independently and according to epigenetic regularities of its own. It is stated that development is the realization of genetic information in which more elementary (molecular) processes unambiguously determine a more complex cellular level which in its turn determines morphogenesis of tissues and organs. Various mechanisms of the appearance of new information in the course of development are considered. The statement is made that new information concerns only some individual characters of the organism, whereas most of information that determines the process of development and the structure of the adult organism is created in the course of evolution, is stored in DNA and inherited. 相似文献
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18.
Ingeborg Frans Kristof Dierckens Sam Crauwels Ado Van Assche J?rgen Leisner Marianne H. Larsen Chris W. Michiels Kris A. Willems Bart Lievens Peter Bossier Hans Rediers 《PloS one》2013,8(8)
Background
Vibriosis is one of the most ubiquitous fish diseases caused by bacteria belonging to the genus Vibrio such as Vibrio (Listonella) anguillarum. Despite a lot of research efforts, the virulence factors and mechanism of V. anguillarum are still insufficiently known, in part because of the lack of standardized virulence assays.Methodology/Principal Findings
We investigated and compared the virulence of 15 V. anguillarum strains obtained from different hosts or non-host niches using a standardized gnotobiotic bioassay with European sea bass (Dicentrarchus labrax L.) larvae as model hosts. In addition, to assess potential relationships between virulence and genotypic and phenotypic characteristics, the strains were characterized by random amplified polymorphic DNA (RAPD) and repetitive extragenic palindromic PCR (rep-PCR) analyses, as well as by phenotypic analyses using Biolog’s Phenotype MicroArray™ technology and some virulence factor assays.Conclusions/Significance
Virulence testing revealed ten virulent and five avirulent strains. While some relation could be established between serotype, genotype and phenotype, no relation was found between virulence and genotypic or phenotypic characteristics, illustrating the complexity of V. anguillarum virulence. Moreover, the standardized gnotobiotic system used in this study has proven its strength as a model to assess and compare the virulence of different V. anguillarum strains in vivo. In this way, the bioassay contributes to the study of mechanisms underlying virulence in V. anguillarum. 相似文献19.
Background
Successful observation of behaviour depends upon knowing both which behaviours to look for and focusing on the appropriate areas of the body to observe them. Behaviour based scoring systems have become increasingly widely used to assess animal pain and distress. Although studies are available demonstrating which behaviours need to be observed, there has been little attempt to assess how effectively observers apply such information when viewing an animal''s behaviour.Methodology/Principal Findings
This study used historical video recordings of New Zealand white rabbits (Oryctolagus cuniculi) considered to be experiencing varying degrees of post-operative pain to assess the pattern of observation and the ability to assess pain exhibited by both experienced and inexperienced human participants (n = 151). Eye tracking equipment was used to identify how quickly, how frequently, for how long different areas of the rabbit''s body were attended to by the participants. Simple visual analgoue scoring was used to assess the pain experienced in each sequence. The results demonstrate that irrespective of their experience or gender, observers focus first, more frequently and for longer on the face, compared to the abdomen, ears, back and hindquarters of the rabbit and that participants were poor at identifying rabbits in pain. Observing the back and hindquarters was correlated with ‘correct’ assessments and observing the face was correlated with ‘incorrect’ assessments.Conclusions
In conclusion, irrespective of experience and gender, observers focused on the face when using behaviour to assess pain and were unable to effectively identify rabbits in pain. Focusing on the face is unlikely to be effective when using behavioural indicators of pain since they involve other body areas. Alternatively, if animals exhibit pain-related facial expressions, then it could improve our ability to assess pain. In addition, these results have potential implications for the use of behaviour to assess how rabbits and potentially other species feel. 相似文献20.
Ian M. Kronish April P. Carson Karina W. Davidson Paul Muntner Monika M. Safford 《PloS one》2012,7(12)