How modern systematics relates to the rumen fungi

The zoosporic fungi comprise a polyphyletic grouping of four classes, the Plasmodiophoromycetes, Oomycetes, Hyphochytriomycetes and Chytridiomycetes. Apart from their absorptive mode of nutrition and the presence of zoospores in some stage of their life cycle, there is little these classes have in common. The zoosporic species of rumen fungi are classified in the Class Chytridiomycetes which is a monophyletic group with extreme diversity in thallus morphology, reproduction and zoospore cytology. The rumen fungi have many characteristics in common with the Spizellomycetaceae but have been given their own family, the Neocallimasticaceae. There are arguments for reducing this family to synonymy with the Spizellomycetaceae, or elevating it to a new order, but before a rational decision can be made, more rumen fungi require detailed examination, especially their zoospore ultrastructure.     

Peptide growth factors in amphibian embryogenesis: intersection of modern molecular approaches with traditional inductive interaction paradigms

Recent discoveries of the role peptide growth factors (PGFs) play in regulating embryonic patterning and differentiation have profoundly influenced research on the molecular biology of early amphibian embryogenesis. Several PGFs have been recognized to be present as endogenous components of amphibian eggs and early embryos, while other PGFs -- which are known from heterologous systems (e.g., Drosophila) -- exert remarkable effects when injected as either protein or mRNA into eggs/embryos or when added to cultured embryonic tissue. For a variety of reasons (reviewed herein) optimism abounds that an understanding in molecular terms of the classical Spemann and Nieuwkoop tissue interactions which are generally believed to drive embryonic patterning is within reach. A critical assessment of the interpretations of some of the contemporary data on PGFs (included herein) should, however, temper some of that optimism. Likely, multiple rather than single PGFs act in a combinatorial fashion to contribute to individual patterning events. As well, substantial redundancy in PGF regulatory circuits probably exists, so the heavy reliance on tissue culture assays and overexpression studies which characterize much recent research needs to be circumvented. Potential experimental approaches for "next generation" experiments are discussed.     

Discontinuous gas exchange in insects: a clarification of hypotheses and approaches

Many adult and diapausing pupal insects exchange respiratory gases discontinuously in a three-phase discontinuous gas exchange cycle (DGC). We summarize the known biophysical characteristics of the DGC and describe current research on the role of convection and diffusion in the DGC, emphasizing control of respiratory water loss. We summarize the main theories for the evolutionary genesis (or, alternatively, nonadaptive genesis) of the DGC: reduction in respiratory water loss (the hygric hypothesis), optimizing gas exchange in hypoxic and hypercapnic environments (the chthonic hypothesis), the hybrid of these two (the chthonic-hygric hypothesis), reducing the toxic properties of oxygen (the oxidative damage hypothesis), the outcome of interactions between O(2) and CO(2) control set points (the emergent property hypothesis), and protection against parasitic invaders (the strolling arthropods hypothesis). We describe specific techniques that are being employed to measure respiratory water loss in the presence or absence of the DGC in an attempt to test the hygric hypothesis, such as the hyperoxic switch and H(2)O/CO(2) regression, and summarize specific areas of the field that are likely to be profitable directions for future research.     

New approaches to the systematics of the ancyrocephalid Monogenea from Nearctic freshwater fishes

A total of 133 ancyrocephalid species found on Nearctic freshwater fishes have been named. Of these, 103 are now considered valid; 14 and 16 have been declared previously as synonyms or species inquirendae, respectively, and Urocleidus rarus Mizelle, 1940, is designated as a species inquirenda in the present work. A cladistic analysis, based on 13 binary and 4 multistate characters and 32 apomorphic character states was carried out. Generalized forms of Entobdella, Gyrodactylus, and Tetraonchus were used to generate a hypothetical outgroup taxon. Thirteen terminal taxa emerged. Of these, 3 (the articulating bar group, Ligictaluridus, and Onchocleidus sensu Wheeler and Beverley-Burton, 1989) have been recognized previously as monophyletic; 3 (Aethycteron, Lyrodiscus, and Salsuginus) were shown to be monophyletic in the present study; 3 (Leptocleidus, Macrohaptor, and Tetracleidus) are monotypic genera; and 4 were identified as unresolved assemblages that contain a number of species considered to be incertae sedis as well as those assigned to the following genera: Aristocleidus Mueller, 1936, Urocleidus sensu Suriano and Beverley-Burton, 1981, Cleidodiscoides Mayes and Miller, 1973, and Cleidodiscus sensu Beverley-Burton and Suriano, 1980. The resultant cladogram was 40 steps long with a consistency index of 0.80. The monophyly of the ingroup is supported by 5 synapomorphies. Comparison and mapping of the parasite cladogram with/onto a family-level cladogram of hosts indicated that the present data provided no unequivocal evidence of cospeciation. Some possible origins for the Nearctic ancyrocephalids are discussed, and the need for further taxonomic studies on the Holarctic ancyrocephalids to explore the possible sister-group relationship between the Nearctic and Eurasian faunas is emphasized.     

Phylogeny estimation: traditional and Bayesian approaches

The construction of evolutionary trees is now a standard part of exploratory sequence analysis. Bayesian methods for estimating trees have recently been proposed as a faster method of incorporating the power of complex statistical models into the process. Researchers who rely on comparative analyses need to understand the theoretical and practical motivations that underlie these new techniques, and how they differ from previous methods. The ability of the new approaches to address previously intractable questions is making phylogenetic analysis an essential tool in an increasing number of areas of genetic research.     

Teratology on the crossroads: historical aspects and modern approaches

Teratology is the science of congenital developmental disorders (CDDs), overt or latent defects of the organism resulting from the effect of internal and external factors on developmental processes. In this article the significance and position of present-day teratology is discussed in the context of development of this branch of science and related disciplines. The authors present an updated overview of the most important milestones and stages of the development of teratology. Based on the analysis of the historical development of theses and theories that represent a decisive contribution to this field, we present a survey of the fundamental principles of experimental and clinical teratology. The aim of observing these principles is to get insight into developmental relations and to understand mechanisms of action on the level of cell populations (elementary morphogenetic processes), tissues and organs. It is important to realize that any negative intervention into the normal course of these processes, either on genetic or non-genetic basis, inevitably leads to a sequence of subsequent changes resulting in the development of congenital developmental disorders. Despite modern approaches of molecular biology and genetics, along with top diagnostic techniques, we are still not able to identify the actual cause in more than 50% of all congenital defects. One-half of the unidentified cases are referred to as "multifactorial", a term that is rather ambiguous. It either means that some of the basic principles of teratogenesis still escape our attention, or the interpretation of some of the well known principles might be misleading. A third possibility is rather pessimistic. The development of the individual is so sophisticated and dependent on a delicate network of a multitude of factors mutually affecting each other that it is extremely prone to give rise to a plethora of spontaneous errors which are unpredictable and impossible to prevent. Nevertheless, the long and complicated history of scientific endeavour has yielded considerable present-day knowledge on causes and mechanisms of CDDs, a history whose beginnings date back to antiquity.     

A critique of silvicultural approaches to managing defoliating insects in North America

1 A variety of silvicultural techniques have been suggested for managing forest defoliating insects. The objectives focus on minimizing defoliation or minimizing damage from defoliation. 2 The theoretical foundations of many approaches have been built upon observation and correlation, and very little reliable empirical evidence exists to support the objectives of silvicultural manipulations. Existing experimental data have yielded inconsistent results. 3 We review the conceptual framework and underlying assumptions of the major silvicultural approaches recommended or in use in North America. 4 Well‐designed, long‐term studies are needed to clarify the effect of silviculture on defoliators and their effect on forests.     

Genetic approaches to reducing losses of stored grain to insects and diseases

Insects and diseases devour or damage a fifth or more of stored food grains each year in many parts of the world. Modern breeding and genomics promise progress in characterizing the resistance to the pests responsible for these losses that is present in the vast and diverse gene pool of cereals, as well as advances in incorporating this resistance into productive and acceptable crop varieties. The impact of such varieties could be dramatic in developing countries, where grain infestations are most common and harmful, and where surging populations require affordable food.     

Traditional and modern approaches to culture of preimplantation mammalian embryos in vitro

This review covers the basic principles and methods of in vitro culture of preimplantation mammalian embryos. The features of in vitro development of embryos of various species of animals with allowance for the composition of nutrient media are described, with special attention paid to those species that have traditionally been considered as laboratory (i.e., mice, rats, and hamsters). The effects of suboptimal culturing conditions of preimplantation embryos on the formation of the phenotype of individuals developed from these embryos are discussed. New approaches to optimize the conditions of the development of preimplantation mammalian embryos in vitro are analyzed.     

Intraspecific variation of thermal reaction norms for development in insects: New approaches and prospects

The main parameters (thermal constants) characterizing the effects of constant temperatures on the duration and rate of development in ectotherms are considered. The advantages and drawbacks of the linear and nonlinear models describing the dependence of the development rate on temperature are discussed. The main patterns of interspecific variation of thermal constants in insects are described. The development of new ideas in the study of intraspecific variation of thermal reaction norms for development in insects is examined. The discrepancies in the data and their interpretation in this field are shown to result mostly from using the traditional methods of determining thermal constants. According to this method, the development rates calculated as reciprocals of the mean development times at each experimental temperature are used for regression analysis. The standard errors calculated according to this method are usually too large. Instead, a fundamentally new method is employed by the authors, according to which the individual development rates calculated for each individual are used for regression analysis of the reciprocals of the mean development times. This method reduces the standard errors of thermal constants by about an order and reveals significant differences between populations and other groups of insects. New data on intraspecific variation of the thermal reaction norms for development in Myrmica ants, the linden bug Pyrrhocoris apterus, and Calliphora blowflies are briefly described and discussed. The possible adaptive significance of these forms of intraspecific variation is discussed. The prospects of research in this new field are outlined.     

Rigorous approaches to species delimitation have significant implications for African crocodilian systematics and conservation

Accurate species delimitation is a central assumption of biology that, in groups such as the Crocodylia, is often hindered by highly conserved morphology and frequent introgression. In Africa, crocodilian systematics has been hampered by complex regional biogeography and confounded taxonomic history. We used rigorous molecular and morphological species delimitation methods to test the hypothesis that the slender-snouted crocodile (Mecistops cataphractus) is composed of multiple species corresponding to the Congolian and Guinean biogeographic zones. Speciation probability was assessed by using 11 mitochondrial and nuclear genes, and cranial morphology for over 100 specimens, representing the full geographical extent of the species distribution. Molecular Bayesian and phylogenetic species delimitation showed unanimous support for two Mecistops species isolated to the Upper Guinean and Congo (including Lower Guinean) biomes that were supported by 13 cranial characters capable of unambiguously diagnosing each species. Fossil-calibrated phylogenetic reconstruction estimated that the species split ± 6.5–7.5 Ma, which is congruent with intraspecies divergence within the sympatric crocodile genus Osteolaemus and the formation of the Cameroon Volcanic Line. Our results underscore the necessity of comprehensive phylogeographic analyses within currently recognized taxa to detect cryptic species within the Crocodylia. We recommend that the community of crocodilian researchers reconsider the conceptualization of crocodilian species especially in the light of the conservation ramifications for this economically and ecologically important group.     

Why small cold-blooded insects pose different conservation problems to birds in modern landscapes

Butterflies and other insects have declined more rapidly than birds over parts of southwest Europe this century, and early attempts to conserve them often failed. Failure occurred mainly because reserve managers did not cater for three differences in their needs compared with those of vertebrates: (1) Many insects occupy very narrow specific niches within their biotopes, often associated with an ephemeral successional stage; (2) although an insect population can sometimes be supported by a small (<1 ha) patch of its specific habitat, an individual habitat patch may remain suitable for no more than 3–10 years and (3) several insect species are too sedentary to colonize new patches of habitat that arise farther than 300 m-1 km from old ones during the period that each remains suitable for breeding. Further complications arise from the dependency of some insects on narrow temperature bands, especially in northwest Europe where many species reach their edges of range and are locked into warm, anthropogenic habitats. The same species have broader or different niches farther south, and their habitats may require very different management across geographical ranges. Despite these problems, conservationists have had considerable success in maintaining populations of threatened insects within nature reserves, once knowledge of their ecology and dynamics was applied to site management.     

Use of traditional and modern health services by Laotian refugees.

Although refugee health care emerged as a special interest in the United States following the influx of almost a million Southeast Asians since 1975, few studies have been done of the influence of refugee traditions on the use of Western medical services. The illness patterns, medical beliefs, and health care behavior of a Southeast Asian refugee group, the Mien from Laos are described in this study. A cohort of 119 Mien refugees living in Richmond, California, was observed for a 6-month period. In-home interviews were undertaken about all episodes of ill health, including treatment and health care decisions. This study shows that the Mien integrate traditional healing beliefs and practices with the use of American health services. Such findings are important because the increasing cultural diversity in the United States, particularly in Western states, necessitates that health care professionals understand the importance of cultural factors for access to and the use of health care by all patients including refugees and other immigrant groups.     

Testing evolutionary models of senescence: traditional approaches and future directions

From an evolutionary perspective, the existence of senescence is a paradox. Why has senescence not been more effectively selected against given its associated decreases in Darwinian fitness? Why does senescence exist and how has it evolved? Three major theories offer explanations: (1) the theory of mutation accumulation suggested by PB Medawar; (2) the theory of antagonistic pleiotropy suggested by GC Williams; and (3) the disposable soma theory suggested by TBL Kirkwood. These three theories differ in the underlying causes of aging that they propose but are not mutually exclusive. This paper compares the specific biological predictions of each theory and discusses the methods and results of previous empirical tests. Lifespan is found to be the most frequently used estimate of senescence in evolutionary investigations. This measurement acts as a proxy for an individual’s rate of senescence, but provides no information on an individual’s senescent state or “biological age” throughout life. In the future, use of alternative longitudinal measures of senescence may facilitate investigation of previously neglected aspects of evolutionary models, such as intra- and inter-individual heterogeneity in the process of aging. DNA methylation data are newly proposed to measure biological aging and are suggested to be particularly useful for such investigations.     

Molecular understanding and modern application of traditional medicines: triumphs and trials

Traditional medicines provide fertile ground for modern drug development, but first they must pass along a pathway of discovery, isolation, and mechanistic studies before eventual deployment in the clinic. Here, we highlight the challenges along this route, focusing on the compounds artemisinin, triptolide, celastrol, capsaicin, and curcumin.     

Complementary approaches to diagnosing marine diseases: a union of the modern and the classic

Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative real-time PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches is necessary for rapid and accurate identification of marine diseases, and emphasize how sole reliance on any one technology or technique may lead disease investigations astray. We present diagnostic approaches at different scales, from the macro (environment, community, population and organismal scales) to the micro (tissue, organ, cell and genomic scales). We use disease case studies from a broad range of taxa to illustrate diagnostic successes from combining traditional and modern diagnostic methods. Finally, we recognize the need for increased capacity of centralized databases, networks, data repositories and contingency plans for diagnosis and management of marine disease.     

Design of a modern liposome and bee venom formulation for the traditional VIT-venom immunotherapy

Traditional venom immunotherapy uses injections of whole bee venom in buffer or adsorbed in Al (OH)(3) in an expensive, time-consuming way. New strategies to improve the safety and efficacy of this treatment with a reduction of injections would, therefore, be of general interest. It would improve patient compliance and provide socio-economic benefits. Liposomes have a long tradition in drug delivery because they increase the therapeutic index and avoid drug degradation and secondary effects. However, bee venom melittin (Mel) and phospholipase (PLA(2)) destroy the phospholipid membranes. Our central idea was to inhibit the PLA(2) and Mel activities through histidine alkylation and or tryptophan oxidation (with pbb, para-bromo-phenacyl bromide, and/or NBS- N-bromosuccinimide, respectively) to make their encapsulations possible within stabilized liposomes. We strongly believe that this formulation will be nontoxic but immunogenic. In this paper, we present the whole bee venom conformation characterization during and after chemical modification and after interaction with liposome by ultraviolet, circular dichroism, and fluorescence spectroscopies. The PLA(2) and Mel activities were measured indirectly by changes in turbidity at 400(n m), rhodamine leak-out, and hemolysis. The native whole bee venom (BV) presented 78.06% of alpha-helical content. The alkylation (A-BV) and succynilation (S-BV) of BV increased 0.44 and 0.20% of its alpha-helical content. The double-modified venom (S-A-BV) had a 0.74% increase of alpha-helical content. The BV chemical modification induced another change on protein conformations observed by Trp that became buried with respect to the native whole BV. It was demonstrated that the liposomal membranes must contain pbb (SPC:Cho:pbb, 26:7:1) as a component to protect them from aggregation and/or fusion. The membranes containing pbb maintained the same turbidity (100%) after incubation with modified venom, in contrast with pbb-free membranes that showed a 15% size decrease. This size decrease was interpreted as membrane degradation and was corroborated by a 50% rhodamine leak-out. Another fact that confirmed our interpretation was the observed 100% inhibition of the hemolytic activity after venom modification with pbb and NBS (S-A-BV). When S-A-BV interacted with liposomes, other protein conformational changes were observed and characterized by the increase of 1.93% on S-A-BV alpha-helical content and the presence of tryptophan residues in a more hydrophobic environment. In other words, the S-A-BV interacted with liposomal membranes, but this interaction was not effective to cause aggregation, leak-out, or fusion. A stable formulation composed by S-A-BV encapsulated within liposomes composed by SPC:Cho:pbb, at a ratio of 26:7:1, was devised. Large unilamellar vesicles of 202.5 nm with a negative surface charge (-24.29 mV) encapsulated 95% of S-A-BV. This formulation can, now, be assayed on VIT.