Who does all the research in conservation biology?

Much of the worlds biodiversity is located within countries with developing economies. We therefore examine how well developing nations and their scientists are represented in three international conservation biology journals (Conservation Biology, Biological Conservation, Biodiversity and Conservation). We found: (1) that 28% of studies were from lower income countries and only 15% of all papers had primary authors from these nations. Of papers from lower income countries, although 80% had at least one local author, only 47% had primary authors from the country where the study was conducted. (2) Lower income countries had more research with a strong applied focus compared to research from high-income countries. (3) In lower income countries research was often funded by international sources but the primary authors of these studies were from affluent nations. (4) The three journals differed in how well they represented lower income nations and their scientists, reflecting their editorial policies for including research from lower income nations. The main reason for the large discrepancy in a countrys output of conservation research is due to the difference in a nations ability to invest in science. However, a brief survey of authors suggests that there is a large amount of information available in lower income and non-English speaking countries that is not easily accessible to the international conservation community. Journals may therefore need to consider altering their policies if we are to improve the representation of research by scientists in lower income nations.     

Alpha, beta, or gamma: where does all the diversity go?

Global taxonomic richness is affected by variation in three components: within-community, or alpha, diversity, between-community, or beta, diversity; and between-region, or gamma, diversity. A data set consisting of 505 faunal lists distributed among 40 stratigraphic intervals and six environmental zones was used to investigate how variation of alpha and beta diversity influenced global diversity through the Paleozoic, and especially during the Ordovician radiations. As first shown by Bambach (1977), alpha diversity increased by 50 to 70 percent in offshore marine environments during the Ordovician and then remained essentially constant of the remainder of the Paleozoic. The increase is insufficient, however, to account for the 300 percent rise observed in global generic diversity. It is shown that beta diversity among level, soft-bottom communities also increased significantly during the early Paleozoic. This change is related to enhanced habitat selection, and presumably increased overall specialization, among diversifying taxa during the Ordovician radiations. Combined with alpha diversity, the measured change in beta diversity still accounts for only about half of the increase in global diversity. Other sources of increase are probably not related to variation in gamma diversity but rather to appearance and/or expansion of organic reefs, hardground communities, bryozoan thickets, and crinoid gardens during the Ordovician.     

A recent marine ancestry for diadromous fishes? Sometimes yes,but mostly no!

Synopsis Diadromy in its three forms (anadromy, catadromy and amphidromy) necessarily involves fish spending part of their lives in the sea. It is not uncommon contention that diadromous fish have a recent marine ancestry and that they are in the process of moving from a marine to a freshwater lifestyle. However, analysis of the distribution of diadromy in fishes suggests that, for most species, it is an ancient life history style though, for a few, a recent marine ancestry seems plausible. In general, there is no reason to consider diadromy anything but a stable and successful life history style, and no reason to regard it as transitional between marine and freshwater habitats.Invited Editorial     

Widespread gamma-secretase activity in the cell, but do we need it at the mitochondria?

gamma-Secretase cleavage of the amyloid precursor protein already subjected to a prior beta-secretase cleavage generates beta-amyloid (Abeta) peptide fragments, which are major constituents of the amyloid plagues found in Alzheimer's disease brain tissues. gamma-Secretase activity and components of the gamma-secretase complex are found in the endoplasmic reticulum-Golgi intermediate compartment, the Golgi, the trans-Golgi network, the plasma membrane, the endosomal-lysosomal system and recently, the mitochondria. Abeta fragments have been shown to be neurotoxic, leading to mitochondrial dysfunction and enhanced apoptotic cell death. However, if Abeta fragments are indeed detrimental to neurons, the widespread presence of enzymatic activity that would result in their generation in the cell appears to make little sense. The presence of a gamma-secretase complex in the mitochondrion, an organelle that is particularly susceptible to Abeta toxicity, is even more puzzling. Emerging evidence suggests that both secreted and intracellular Abeta fragments have endogenous functions. Also, while the fibrillogenic Abeta1-42 is clearly neurotoxic, the more abundant and soluble Abeta1-40 is an antioxidant and could potentially be neuroprotective in several ways. A "physiological" amount of Abeta1-40 production by cellular gamma-secretase activity may be part of the neuron's natural counter against oxidative damage, in addition to endogenous roles in neuronal survival and modulation of synaptic transmission. In any case, whether Abeta is produced locally in the mitochondria and the function for mitochondrial Abeta, if produced, is yet unclear.     

Why does the gut choose apolipoprotein B48 but not B100 for chylomicron formation?

Chylomicrons produced by the human gut contain apolipoprotein (apo) B48, whereas very-low-density lipoproteins made by the liver contain apo B100. To study how these molecules function during lipid absorption, we examined the process as it occurs in apobec-1 knockout mice (able to produce only apo B100; KO) and in wild-type mice (of which the normally functioning intestine makes apo B48, WT). Using the lymph fistula model, we studied the process of lipid absorption when animals were intraduodenally infused with a lipid emulsion (4 or 6 micromol/h of triolein). KO mice transported triacylglycerol (TG) as efficiently as WT mice when infused with the lower lipid dose; when infused with 6 micromol/h of triolein, however, KO mice transported significantly less TG to lymph than WT mice, leading to the accumulation of mucosal TG. Interestingly, the size of lipoprotein particles from both KO and WT mice were enlarged to chylomicron-size particles during absorption of the higher dose. These increased-size particles produced by KO mice were not associated with increased apo AIV secretion. However, we found that the gut of the KO mice secreted fewer apo B molecules to lymph (compared with WT), during both fasting and lipid infusion, leading us to conclude that the KO gut produced fewer numbers of TG-rich lipoproteins (including chylomicron) than the wild-type animals. The reduced apo B secretion in KO mice was not related to reduced microsomal triglyceride transfer protein lipid transfer activity. We propose that apo B48 is the preferred protein for the gut to coat chylomicrons to ensure efficient chylomicron formation and lipid absorption.     

Looking for food in all the right places?

Examining a potential functional role for growth hormone secretagogue receptors in the hippocampus, Diano and colleagues (Diano et al., 2006), demonstrate novel actions of the orexigenic peptide ghrelin in hippocampal synaptic architecture, LTP, and learning and memory. These data suggest functional links between metabolic signaling and higher neural function.     

Frequency of bird hybrids: does detectability make all the difference?

The number of hybrids recorded in the field may be biased because these data may simply reflect the detectability of a hybrid pairing. A questionnaire was constructed for assessing the detectability of natural avian hybrids. Ratings from 17 independent experienced observers were subjected to factor analysis and all observers loaded onto the same single factor. The reliability was extremely high (Cronbachs alpha=0.96). Initially, I found a weak positive and significant correlation between the number of hybrids and their detectability index (r_s=0.268; P=0.015; n=81). However, the respective correlations within three orders and one family containing enough hybrids for analysis revealed non-significant results. Significant differences existed among orders with respect to both detectability and hybrid frequency. At the family level, differences existed in detectability, but not in the number of hybrids recorded. Furthermore, I found no publication bias. These results suggest a general influence of detectability and on higher taxonomic levels, and that either detectability or the number of hybrids vary between orders possibly due to phylogenetic effects. Data about hybrids should be used in a cautious manner in analyses across a wide range of species, but seem unbiased when restricted to analyses within orders and families. As a rule of thumb, distinctness of hybrids seems to be a function of the plumage difference between the hybridising species.Communicated by F. Bairlein