Influence of ultraviolet-B radiation on growth,prevalence of deformities,and susceptibility to predation in Cascades frog (<Emphasis Type="Italic">Rana cascadae</Emphasis>) larvae

Ambient levels of ultraviolet-B radiation (UVB) have a variety of detrimental effects on aquatic organisms. These include death and effects on growth, development, physiology, and behavior. Amphibians show all of these effects. However, the effects vary with species, life history stage, and ecological context. Little is known about the implications of the detrimental effects of UVB on ecological dynamics. Our study was designed to test how UVB may affect predator–prey interactions, an important ecological dynamic. Specifically, we tested the effect of UVB on the susceptibility of Cascades frog (Rana cascadae) larvae to predation by rough-skinned newts (Taricha granulosa). We also further examined the sublethal effects of UVB on growth and development in Cascades frog larvae. We found no direct effect of UVB exposure on survival. However, UVB-exposed frog larvae displayed decreased growth and increased prevalence of deformities. UVB also caused increased susceptibility to predation, but there was a significant treatment–block interaction. UVB increased susceptibility to predation in two out of five blocks of Cascades frogs. The other three blocks did not show an effect of UVB on susceptibility to predation. Our study suggests that UVB can alter susceptibility to predation in at least one amphibian species. UVB-induced alteration of predator–prey interactions could potentially lead to changes at the population, community, and ecosystem levels. Handling editor: K. Martens     

The Erwin equation of biodiversity: From little steps to quantum leaps in the discovery of tropical insect diversity

Almost 40 years ago, Terry L. Erwin published a seemingly audacious proposition: There may be as many as 30 million species of insects in the world. Here, we translate Erwin's verbal argument into a diversity-ratio model—the Erwin Equation of Biodiversity—and discuss how it has inspired other biodiversity estimates. We categorize, describe the assumptions for, and summarize the most commonly used methods for calculating estimates of global biodiversity. Subsequent diversity-ratio extrapolations have incorporated parameters representing empirical insect specialization ratios, and how insect specialization changes at different spatial scales. Other approaches include macroecological diversity models and diversity curves. For many insect groups with poorly known taxonomies, diversity estimates are based on the opinions of taxonomic experts. We illustrate our current understanding of insect diversity by focusing on the six most speciose insect orders worldwide. For each order, we compiled estimates of the (a) maximum estimated number of species, (b) minimum estimated number of species, and (c) number of currently described species. By integrating these approaches and considering new information, we believe an estimate of 5.5 million species of insects in the world is much too low. New molecular methodologies (e.g., metabarcoding and NGS studies) are revealing daunting numbers of cryptic and previously undescribed species, at the same time increasing our precision but also uncertainty about present estimates. Not until technologies advance and sampling become more comprehensive, especially of tropical biotas, will we be able to make robust estimates of the total number of insect species on Earth.     

The Allee Effect in Mechanistic Models Based on Inter-individual Interaction Processes

Recently, Eskola and Geritz (Bull. Math. Biol. 69:329–346, 2007) showed that several discrete-time population models can be derived mechanistically within a single ecological framework by varying the within-season patterns of reproduction and inter-individual aggression. However, these models do not have the Allee effect. In this paper, we modify the original modelling framework by adding different mate finding processes, and thus derive mechanistically several population models with the Allee effect.     

Protein oligomerization mediated by the transmembrane carboxyl terminal domain of Bcl-XL

Bcl-XL is a pro-survival member of the Bcl-2 family that can be found in the outer mitochondrial membrane and in soluble cytosolic homodimers. Bcl-XL can bind pro-apoptotic members of this family preventing them from activating the execution phase of apoptosis. Bcl-XL has been shown to homodimerize in different ways, although most binding and structural assays have been carried out in the absence of its carboxyl terminal transmembrane domain. We show here that this domain can by itself direct protein oligomerization, which could be related to its previously reported role in mitochondrial morphology alterations and apoptosis inhibition.     

Conservation of key members in the course of the evolution of the insulin signaling pathway

Our understanding of the evolution of the insulin signaling pathway (ISP) is still incomplete. One intriguing unanswered question is the explanation of the emergence of the glucostatic role of insulin in mammals. To find out whether this is due to the development of new sets of signaling transduction elements in these organisms, or to the establishment of new interactions between pre-existing proteins, we rebuilt putative orthologous ISPs in 17 eukaryotic organisms. Then, we computed the conservation of orthologous ISPs at different levels, from sequence similarity of orthologous proteins to co-evolution of interacting domains. We found that the emergence of glucostatic role in mammals can neither be explained by the development of new sets of signaling elements, nor by the establishment of new interactions between pre-existing proteins. The comparison of orthologous IRS molecules indicates that only in mammals have they acquired their complete functionality as efficient recruiters of effector sub-pathways.     

Strategies for Self-organization: Learning from a Village-level Community-based Conservation Initiative in India

Self-organization is a key condition to the success of community-based conservation initiatives, including those recognized by the Equator Initiative of the UNDP. This paper contributes to emerging scholarship that focuses on community-based conservation in South Asia and in particular examines self-organization strategies within a small-scale community-based conservation initiative in a cross-cultural setting to further understanding about how such initiatives originate, sustain and grow. This is achieved through a case study of the Baripada Forest Protection Initiative in India by utilizing in-depth interviews and focus groups. In addition to certain often-cited strategies for self-organization, the Baripada initiative included unique features of self-organization such as village community design, implementation and adaptation of rules for local natural resources use and conservation, little need for financial support, and significant mobilization of human resources. These strategies, along with emerging social learning opportunities (e.g., a community plant diversity register) inspired by the Baripada initiative, inform and enrich the criteria for designing and evaluating conservation and development initiatives, irrespective of their scale.     

Comparison of the cardiac effects between quinazoline-based α<Subscript>1</Subscript>-adrenoceptor antagonists on occlusion–reperfusion injury

Quinazoline-based compounds such as prazosin and its congeners including doxazosin, bunazosin, and terazosin are widely used as antihypertensive agents. However, there were many clinical observations showing that using these agents may result in higher risk of cardiovascular accidents in recent years. In this study, we compared the effects of four α-adrenoceptor antagonists: prazosin, doxazosin, bunazosin, and terazosin on occlusion–reperfusion injury. Langendorff-perfused rat hearts were pretreated with these four antagonists, and then the left main coronary artery was occluded. After 30 min occlusion, the hearts were reperfused for 2 h and the infarct sizes were measured. Two of the compounds studied, prazosin and doxazosin, apparently increased infarct size, CK-MB, and LDH activities after 2 h reperfusion. In contrast, bunazosin decreased infarct size and those biochemical indicators of cellular damage compared to control hearts. Although infarct size after reperfusion was differently changed by these four α-adrenoceptor antagonists, TUNEL-positive nuclei and caspase-3 protein expressions of all the groups were not significantly different. We supposed that the different effects of these four agents on infarct size came from the difference in necrosis rather than apoptosis.