Invertebrate models for biomedical research, testing, and education

Invertebrate animals have been used as medicinals for 4,000 years and have served as models for research and teaching since the late 1800s. Interest in invertebrate models has increased over the past several decades as the research community has responded to public concerns about the use of vertebrate animals in research. As a result, invertebrates are being evaluated and recognized as models for many diseases and conditions. Their use has led to discoveries in almost every area of biology and medicine--from embryonic development to aging processes. Species range from terrestrial invertebrates such as nematodes and insects to freshwater and marine life including planarians, crustaceans, molluscs, and many others. The most often used models are the fruit fly Drosophila melanogaster and the minuscule nematode Caenorhabditis elegans. Topics in this article are categorized by biologic system, process, or disease with discussion of associated invertebrate models. Sections on bioactive products discovered from invertebrates follow the models section, and the article concludes with uses of invertebrates in teaching. The models reviewed can serve as references for scientists, researchers, veterinarians, institutional animal care and use committees (IACUCs), and others interested in alternatives to vertebrate animals.     

Reference bias in reports of drug trials.

Articles published before 1985 describing double blind trials of two or more non-steroidal anti-inflammatory drugs in rheumatoid arthritis were examined to see whether there was any bias in the references they cited. Althogether 244 articles meeting the criteria were found through a Medline search and through examining the reference lists of the articles retrieved. The drugs compared in the studies were classified as new or as control drugs and the outcome of the trial as positive or not positive. The reference lists of all papers with references to other trials on the new drug were then examined for reference bias. Positive bias was judged to have occurred if the reference list contained a higher proportion of references with a positive outcome for that drug than among all the articles assumed to have been available to the authors (those published more than two years earlier than the index article). Altogether 133 of the 244 articles were excluded for various reasons--for example, 44 because of multiple publication and 19 because they had no references. Among the 111 articles analysed bias was not possible in the references of 35 (because all the references gave the same outcome); 10 had a neutral selection of references, 22 a negative selection, and 44 a positive selection--a significant positive bias. This bias was not caused by better scientific standing of the cited articles over the uncited ones. Thus retrieving literature by scanning reference lists may produce a biased sample of articles, and reference bias may also render the conclusions of an article less reliable.     

杀虫剂轮用和混用对害虫种群抗性演化的影响

杀虫剂轮用和混用是当前害虫抗药性治理中最常采用的两种用药策略。该文用抗性模型和室内试验对轮用和混用延缓害虫抗性演化的效果及轮用最佳间隔期问题作了研究。模型模拟结果表明,在延缓害虫抗性演化方面轮用和混用对抗性演化的影响主要取决于杀虫剂作用强度、抗性基因型个体的适合度大小和杀虫剂混用后的毒理效应类型。两种杀虫剂轮用时,轮用间隔期以1(即两种杀虫剂隔次施用)为佳。以模型昆虫小菜蛾Plutella xylostella在室内试验结果表明,氰戊菊酯单用(I)及与杀虫单轮用(II)和混用(1∶1)(III)连续处理8代后,抗性个体频率为0.01的小菜蛾种群其3龄幼虫对氰戊菊酯的抗性分别上升了75.87(I)、28.67(II)和58.72(III)倍,与模型模拟结果表现出较好的一致性。据此,作者认为抗性模型可用于预测害虫抗性演化和评价抗性治理策略。     

A social science view on the FRAME symposium: identities and networks

This paper, written by two social scientists, presents a social science perspective on the issues raised at the FRAME symposium on Human Alternatives to Animal Studies. Drawing upon the authors' experience of conducting research with stem cell scientists, issues around access to human tissue for in vitro uses are considered. The paper concludes by raising questions pertinent to both interested social scientists and the Three Rs agenda.     

Haplodiploidy, sex, and the evolution of pesticide resistance

The assumption that males and females are equally tolerant to pesticides in haplodiploid arthropods led to the prediction that the evolution of resistance is faster in haplodiploid than in diploid arthropods. However, in this review, it was found that the ratio of male to female tolerance is substantially smaller in haplodiploid than in diploid arthropods, indicating that resistance alleles are not strongly up-regulated in haploid males. In addition, males were generally less tolerant than females in both haplodiploid and diploid arthropods. Factors such as sexual size dimorphism and sex-dependent selection may account for the lower tolerance in males than in females. Little among-population variation in the ratio of male to female tolerance was found in three species. Moreover, the tolerance ratio generally remained unchanged by selection for resistance to pesticides, although significant among-species variation was present within arthropod orders. This indicates that sexual dimorphism in pesticide tolerance evolves at a slower rate than resistance to pesticides. Simulations considering between-sex differences in pesticide tolerance showed that resistance evolution can be slower in haplodiploids than in diploids. Recessive resistance, low male tolerance to pesticides, fitness costs expressed in males, and the use of refuges contributed in substantially delaying the evolution of resistance in haplodiploid arthropods. These findings cast a new perspective on the evolution of pesticide resistance in haplodiploid herbivores and natural enemies.     

You say you want an evolution? A role for scientists in science education

We conducted a national survey of likely U.S. voters to examine acceptance of evolution, attitudes toward science and scientists, and opportunities for promoting science education. Most respondents accepted that life evolved, many accepted that it evolved through natural processes, and more favored teaching evolution than creationism or intelligent design in science classes. The majority ranked developing medicines and curing diseases as the most important contributions of science to society, and they found promoting understanding of evolutionary science's contribution to medicine to be a convincing reason to teach evolution. Respondents viewed scientists, teachers, and medical professionals favorably, and most were interested in hearing from these groups about science, including evolution. These data suggest that the scientific community has an important role to play in encouraging public support for science education.     

Does nothing in evolution make sense except in the light of population genetics?

“The Origins of Genome Architecture” by Michael Lynch (2007) may not immediately sound like a book that someone interested in the philosophy of biology would grab off the shelf. But there are three important reasons why you should read this book. Firstly, if you want to understand biological evolution, you should have at least a passing familiarity with evolutionary change at the level of the genome. This is not to say that everyone interested in evolution should be a geneticist or a bioinformatician, but that a working knowledge of genetic change is an essential part of the intellectual toolkit of modern evolutionary biology, even if your primary focus is the evolution of behaviour or the diversity of communities. Secondly, this book provides excellent examples of another important tool in the biologist’s intellectual toolkit, but one that is rarely explained or illustrated to such an extent: null (or neutral) models. The role null models play in testing hypotheses in evolution is a central focus of this book. Thirdly, as an accomplished work of advocacy for a strictly microevolutionary view of evolution, this book provides grist for the mill for the important debate about whether population genetic processes are the sine qua non of evolutionary explanations.     

Waddington redux: models and explanation in stem cell and systems biology

Stem cell biology and systems biology are two prominent new approaches to studying cell development. In stem cell biology, the predominant method is experimental manipulation of concrete cells and tissues. Systems biology, in contrast, emphasizes mathematical modeling of cellular systems. For scientists and philosophers interested in development, an important question arises: how should the two approaches relate? This essay proposes an answer, using the model of Waddington’s landscape to triangulate between stem cell and systems approaches. This simple abstract model represents development as an undulating surface of hills and valleys. Originally constructed by C. H. Waddington to visually explicate an integrated theory of genetics, development and evolution, the landscape model can play an updated unificatory role. I examine this model’s structure, representational assumptions, and uses in all three contexts, and argue that explanations of cell development require both mathematical models and concrete experiments. On this view, the two approaches are interdependent, with mathematical models playing a crucial but circumscribed role in explanations of cell development.     

Plant virtues are in the eyes of the beholders: A comparison of known palm uses among indigenous and folk communities of Southwestern Amazonia

Despite its central importance to tropical forest conservation, the understanding of patterns in traditional resource use still is incipient. To address this deficiency, we compared known palm uses among two indigenous (Yawanawd and Kaxinawá) and two folk (rubber tapper and ribeirinho) communities in Southwestern Amazonia (Acre, Brazil). We conducted one-hundred-and -forty semi-structured “checklist” interviews about palm uses with male and female adults in the four communities. The knowledge of each community about the uses of the 17 palm species common to all communities was compared by testing for significant differences in the mean number of uses cited per informant and by calculating the Jaccard similarity index of known uses of palm species among the four communities. The following three hypotheses were confirmed: 1) the use of palms differs according to the cultural preferences of each community; 2) indigenous communities know significantly more about palm uses than folk communities; and 3) part of the indigenous knowledge was acquired through contact with Amazonian folk communities.     

Impact analysis of a regional scientific journal (1980-2000): supporting promising local researchers pays the greatest dividends

During the past 28 years, the journal "Collegium Antropologicum" has continuously served as one of the main disseminators of anthropological scientific production in Central and Eastern Europe. The journal was committed to its role of a multidisciplinary platform for presenting wide range of research topics relevant to anthropology, from investigations within social and cultural anthropology and archaeology to those covering contemporary population genetics, human evolution and biomedical issues. Two key strategies aimed at sustaining and increasing the impact of this journal were oriented towards: (i) identification of promising local groups of researchers who were at disadvantage by many aspects (e.g. educational curricula, financial supports, language barriers etc.) when trying to publish their research internationally, and (ii) invitation and encouragement of already established international scientists to make contributions for "Collegium Antropologicum". From 1980-2000, 89 articles (or 6.3% of all published papers during that period) were cited 6 or more times, contributing disproportionately to journal's impact (nearly a third of all citations received). In an attempt to identify such papers more readily among the submissions to the journal in the future, we analyzed research topics and affiliations of the authors among the 89 papers receiving most citations in comparison to all papers published. Among the papers most frequently cited, we found greater-than-expected prevalence of Croatian researchers (especially when publishing in collaboration with international scientists) and studies of special populations. Several papers received more than 25 citations or had overall citation intensity greater than 2 per year. This implies that an interesting article from a local group of researchers can still resonate with international audience although published in a regional journal. Present analysis supports current editorial strategy that with a help of the international consulting editorial board continuously improves international recognition of this journal. The results imply that a balanced encouragement to promising local groups of researchers and to contributions of already established international scientists is a strategy superior to others in maintaining and increasing the impact of this regional journal.     

Assessing the ecology in ecotoxicology: a review and synthesis in freshwater systems

The field of ecotoxicology is experiencing a surge in attention among ecologists as we gain a deeper appreciation for how contaminants can impact natural ecosystems. This interest is particularly strong in aquatic systems where many non-target organisms experience pesticides. In this article, we assess how pesticides affect freshwater systems by applying the conceptual framework of density- and trait-mediated indirect effects from the field of basic ecology. We demonstrate the utility of this framework for understanding the conditions under which pesticides affect species interactions, communities and ecosystems. Through the integration of laboratory toxicity tests and this ecological framework, ecotoxicologists should be better able to identify the mechanisms through which pesticides affect communities and ecosystems. We also identify several areas of research that are in critical need of empirical attention including synergistic effects between pesticides and natural stressors, the importance of pesticides on community assembly via habitat preferences and oviposition effects, the timing and frequency of pesticide applications, pesticide effects on population dynamics, the evolution of pesticide resistance in non-target organisms and ecosystem recovery. With this knowledge, one can improve upon management decisions and help protect non-target species that are of conservation concern.     

A comparative genomic analysis of Xanthomonas arboricola pv. juglandis strains reveal hallmarks of mobile genetic elements in the adaptation and accelerated evolution of virulence

Xanthomonas arboricola pv. juglandis (Xaj) is the most significant aboveground walnut bacterial pathogen. Disease management uses copper-based pesticides which induce pathogen resistance. We examined the genetic repertoire associated with adaptation and virulence evolution in Xaj. Comparative genomics of 32 Xaj strains reveal the possible acquisition and propagation of virulence factors via insertion sequences (IS). Fine-scale annotation revealed a Tn3 transposon (TnXaj417) encoding copper resistance genes acquired by horizontal gene transfer and associated with adaptation and tolerance to metal-based pesticides commonly used to manage pathogens in orchard ecosystems. Phylogenomic analysis reveals IS involvement in acquisition and diversification of type III effector proteins ranging from two to eight in non-pathogenic strains, 16 to 20 in pathogenic strains, besides six other putative effectors with a reduced identity degree found mostly among pathogenic strains. Yersiniabactin, xopK, xopAI, and antibiotic resistance genes are also located near ISs or inside genomic islands and structures resembling composite transposons.     

Cryptic confounding compounds: a brief consideration of the influences of anthropogenic contaminants on courtship and mating behavior

Contaminants, like pesticides, polychlorinated biphenyls (PCBs), dioxins, and metals, are persistent and ubiquitous and are known to threaten the environment. Traditionally, scientists have considered the direct physiological risks that these contaminants pose. However, scientists have just begun to integrate ethology and toxicology to investigate the effects that contaminants have on behavior. This review considers the potential for contaminant effects on mating behavior. Here, we assess the growing body of research concerning disruptions in sexual differentiation, courtship, sexual receptivity, arousal, and mating. We discuss the implications of these disruptions on conservation efforts and highlight the importance of recognizing the potential for environmental stressors to affect behavioral experimentation. More specifically, we consider the negative implications for anthropogenic contaminants to affect the immediate behavior of animals and their potential to have cascading and/or long-term effects on the behavioral ecology and evolution of populations. Overall, we aim to raise awareness of the confounding influence that contaminants can have and promote caution when interpreting results where the potential for cryptic effects are possible.     

Invasion Success and Community Resistance in Single and Multiple Species Invasion Models: Do the Models Support the Conclusions?

Elton's concept of community-level resistance to invasion has derived significant theoretical support from community assembly models in which species invade (colonize) singly at low densities. Several theoretical models have provided support to this concept and are frequently cited as providing evidence that invasion resistance occurs in nature. The underlying assumptions of these models however, are derived from island or island-like systems in which species invade infrequently at low abundances. We suggest that these island-like models cannot be generalized to systems in which species arrive in greater frequencies and densities. To investigate the effects of altering the basic assumptions of these original models, we utilized assembly algorithms similar to those used in previous studies, but allowed either two species to invade per time step or single species invasions at relatively high inoculation densities. In these models, invasion resistance only occurred when the invasion process was restricted to single species invading at low densities (as in previous models). When two species were allowed to invade per time step, invasion resistant states did not occur in any of 20 simulated communities, even after 10,000 invasion events. Relaxation of the assumption of invasion at low density also resulted in a lack of invasion resistance. These results may explain why the strict concept of complete invasion resistance appears only to operate in island and island-like systems.     

Bifurcation analysis of piecewise smooth ecological models

The aim of this paper is the study of the long-term behavior of population communities described by piecewise smooth models (known as Filippov systems). Models of this kind are often used to describe populations with selective switching between alternative habitats or diets or to mimic the evolution of an exploited resource where harvesting is forbidden when the resource is below a prescribed threshold. The analysis is carried out by performing the bifurcation analysis of the model with respect to two parameters. A relatively simple method, called the puzzle method, is proposed to construct the complete bifurcation diagram step-by-step. The method is illustrated through four examples concerning the exploitation and protection of interacting populations.     

Indigenous Medicinal Plants in Mexico: the Example of the Nahua (Sierra de Zongolica)

As in most peasant cultures medicinal plants are a very important resource for the Nahua of the Sierra de Zongolica (Mexico). Documentation of the current indigenous medicinal uses of 203 plants in this region was conducted during 18 months of fieldwork. The 816 individual reports documented were divided into nine groups of indigenous uses. The frequency of usage of the individual plants reported was employed in the analysis of the ethnobotanical importance of the respective plants. Plants cited more frequently in a group of indigenous uses are regarded as of greater ethnobotanical importance than those cited only by a few informants. Data on phytochemistry, pharmacology and ethnobotany from the scientific literature were used to evaluate possible biological or pharmacological and toxicological effects of some particularly important plants. For most plants detailed studies on these actions are still lacking, which would allow a conclusive evaluation. This ethnobotanical evaluation forms the basis for such studies which have been started on some plants, and for better understanding their potential as minor economic products of the region. These uses may also give incentives to the conservation of the local biodiversity.     

Using functional–structural plant models to study, understand and integrate plant development and ecophysiology

Functional–structural plant models (FSPMs) explore and integrate relationships between a plant’s structure and processes that underlie its growth and development. In recent years, the range of topics being addressed by scientists interested in functional–structural plant modelling has expanded greatly. FSPM techniques are now being used to dynamically simulate growth and development occurring at the microscopic scale involving cell division in plant meristems to the macroscopic scales of whole plants and plant communities. The plant types studied also cover a broad spectrum from algae to trees. FSPM is highly interdisciplinary and involves scientists with backgrounds in plant physiology, plant anatomy, plant morphology, mathematics, computer science, cellular biology, ecology and agronomy. This special issue of Annals of Botany features selected papers that provide examples of comprehensive functional–structural models, models of key processes such as partitioning of resources, software for modelling plants and plant environments, data acquisition and processing techniques and applications of functional–structural plant models for agronomic purposes.     

Cross-Cultural Ethnobiology in the Western Balkans: Medical Ethnobotany and Ethnozoology Among Albanians and Serbs in the Pešter Plateau,Sandžak,South-Western Serbia

An ethnobiological study concerning the medical ethnobotany and ethnozoology of two neighbouring communities of Serbians and Albanians living in the Pešter plateau (south-western Serbia) was conducted, the latter representing a diasporic community that immigrated to the area approximately three centuries ago. Sixty-two botanical taxa used in 129 plant-based remedies and 204 folk plant uses were recorded. In addition, 31 animal-derived remedies and 27 mineral or non-indigenous products were also documented. Approximately half of the recorded phytotherepeutical uses have been recorded for the first time in the ethnobotany of the Western Balkans and more than one-third of these uses have no correlation with Western evidence-based phytotherapy. Moreover, while both communities use approximately the same number of medicinal plants, two-thirds of the botanical taxa, but only one-third of plant folk medical uses are found in common among the two communities. These findings demonstrate that the two communities, although having lived in close proximity to each other during the past three centuries and in a relatively low biodiverse environment, have maintained or developed unique phytotherapeutical trajectories. The differences between the two folk medical biologies of these communities are reflective of the specific history of the Albanian diaspora, and of the complex processes of its cultural adaptation over the last three centuries.     

An analysis of the scientific publications of the A. A. Bogomolets Institute of Physiology of the Academy of Sciences of Ukraine]

Scientific publications from three sectors of the Institute have analyzed for the period since 1979 till 1988 inclusive. The analysis is based on data of annual reference books Science Citation Index (SCI) and lists of publications of each researcher of the Institute. It is shown that with almost equal numerical strength of researchers and similar number of publications the sector of molecular physiology contributed 43.6% to cited works 48.2% of these works are included into database of SCI. Such indices for the sectors of neurophysiology and physiology of visceral systems accounted for 33%, 33.4% and 23.4, 18.4% respectively. It is of interest that 47.5% of references to the cited works of the molecular physiology sector were made by foreign scientists and self-citation constituted 17.4%, while for the other sectors such indices had a reverse relationship. The problem on objectification of estimation of research is under discussion.