Phylogeography of the freshwater crab Potamon persicum (Decapoda: Potamidae): an ancestral ring species?

The Zagros Mountains, characterized by complex topography and three large drainage systems, harbor the endemic freshwater crab Potamon persicum in Iran. Our study delves into the evolutionary history of P. persicum, utilizing two mitochondrial and one nuclear marker. We collected 214 specimens from 24 localities, identifying 21 haplotypes grouped into two major evolutionary lineages. Substantial differentiation exists between drainage systems and lineages. Historical demographic analysis revealed a significant decrease in population size during the late Holocene, accompanied by a recent population bottleneck. Species distribution modeling has revealed eastward shifts in suitable habitats between the last glacial maximum and the present day. Following the last glacial maximum, habitat fragmentation occurred, resulting in the establishment of small populations. These smaller populations are more vulnerable to climatic and geological events, thereby limiting gene flow and accelerating genetic differentiation within species. Historical biogeographic analysis traced the origin of P. persicum to the western Zagros Mountains, with major genetic divergence occurring during the Pleistocene. Our genetic analyses suggest that P. persicum may have shown a genetic pattern similar to a classical ring species before the Pleistocene. The Namak Lake sub-basin could have served as a contact zone where populations did not interbreed but were connected through gene flow in a geographic ring. Currently, genetic separation is evident between basins, indicating that P. persicum in the Zagros Mountains is not a contemporary ring species. Also, our biogeographical analysis estimated that range evolution may have been driven initially by dispersal, and only during the late Pleistocene by vicariance.

[Forms of Use of Psychosomatic Rehabilitation by Patients - A Study on the Significance of the Moment of Entrance in the Rehabilitation Setting and the Dependence on the Individual Situation at Admission to Rehabilitation]. / Nutzungsformen psychosomatischer Rehabilitation.

BACKGROUND AND AIMS: As expectancies of patients and physicians in psychosomatic rehabilitation are not always congruent, we focused on the patients' subjective expectancies toward rehabilitation in relation to the perceived benefit of the treatment for return to work and on the individual forms of utilization of the therapeutic services in the setting of psychosomatic clinics. A special focus was given to the changes in the patients' evaluations and coping behaviours over a follow-up period of 18 months. METHODS: N=105 participants (F-3/F-4 Main-Diagnosis, specific vocational problems, under 3 months jobless) of 4 psychosomatic rehabilitation settings were asked for their situation at the end of the rehabilitation by means of a questionnaire. 33 patients out of the questionnaire-sample who consented to participate were interviewed for 3 times (6, 12 and 18 months after release from the clinic) by means of episodic-narrative interviewing technique. RESULTS: Some characteristic expectancies and modes of use of the psychosomatic rehabilitation setting by the patients could be identified. The uses of the clinics' therapeutic services by the patients are pointing to different subjective felt needs that correlate with the state of coping with the illness and other psychosocial features at the moment of entrance in the rehabilitation setting. The patients' actual situation can be identified by retrospective tracing his/her positioning on an ideal-typed trajectory of the whole illness process from the beginning of the first symptoms up to Return to work. The results give hints for more individualised and person-centred propositions in rehabilitation-settings.

[Return to Work from Vocational RetrainingA Long-Term Analysis of Individual Trajectories: Biografical and Structural Conditions of Success and Failure]. / Von der beruflichen Vollqualifizierungsmaßnahme zurück in ArbeitEine Langzeitanalyse individueller Verlaufskarrieren und ihrer biografischen und strukturellen Bedingungen.

BACKGROUND AND AIMS: The study aimed at the reconstruction of the trajectories of participants of a two-year vocational-retraining into new workplaces thereby identifying favourable and risky conditions of the return-to-work process. From a practical point of view the study identified special needs and necessities for after-care facilities. METHODS: A Mixed-Method-Design was used. Quantitatively the follow-up-study included 214 persons who participated for three times on filling out a questionnaire over a period of eighteen months after the end of the vocational retraining. In the qualitative part of the study thirty persons consented to participate in a narrative-episodic interview on their vocational biography, their illness experiences at work and their way back into work. The study focused on the experiences of the participants from within, on their decision-making, coping, and rearrangement processes as well as on the experienced support from family members and rehabilitation professionals. RESULTS: About 75% of the participants of the vocational retraining succeeded in getting a job within the range of 18 months after finishing the retraining. Indicators for successful Return to Work are a high identification with the new vocation, effective coping with the remaining health problems, and an accepted arrangement with the disabilities in the work place and in everyday-life, a positive anticipation of the health condition in the future, and last but not least a satisfying social inclusion. As specific risk constellations for Return to Work emerged a lack of partnership, unfinished mental coping with the illness, negative subjective health prognosis, and a more passive attitude to life.

Divergent evolutionary origins and biogeographic histories of two freshwater crabs (Brachyura: Potamonautes) on the West African conveyer belt islands of São Tomé and Príncipe.

We examined the colonization history and phylogeographic structure of the two endemic freshwater crab species (Potamonautes margaritarius and P. principe) inhabiting the volcanic islands of São Tomé and Príncipe, respectively, using mitochondrial and nuclear DNA sequence data. All samples were sequenced for the mtDNA COI locus and used in the phylogeographic analyses, while a single specimen per lineage was sequenced for the two remaining loci (16S rRNA and histone 3) and used in the phylogenetic reconstruction. Phylogenetic results reveal that P. principe diverged early within a clade of East/Southern African Potamonautes during the Miocene, while P. margaritarius diverged between the Late Eocene to Early Miocene. Furthermore, the two species are not sister taxa and are distantly related. These results corroborate previously hypothesised independent transoceanic dispersal events that resulted in the establishment of the endemic freshwater crab fauna of the two islands. Within P. margaritarius, we observed two reciprocally monophyletic clades on São Tomé Island. Clade one occurred in the southeast and southwest of the island, while clade two occurred in the northeast and the northwest; the divergence between the latter two clades was estimated to be of Pleistocene age. The two clades within P. margartarius are genetically highly structured and characterised by the absence of shared maternal haplotypes, suggesting possible speciation within P. margartarius. In contrast P. principe exhibits a shallow population genetic structure. Possible mechanisms of colonization and cladogenesis in the two freshwater crabs are discussed.

A comprehensive phylogeny of the genus Kurixalus (Rhacophoridae, Anura) sheds light on the geographical range evolution of frilled swamp treefrogs.

Currently, the genus Kurixalus comprises 14 species distributed in Southern, Southeast and East Asia. Because of their relatively low dispersal capability and intolerance of seawater, this group is ideal for the study of terrestrial range evolution, especially that portion of its range that extends into the island archipelagos of Southern Asia. We assembled a large dataset of mitochondrial and nuclear genes, and estimated phylogeny by maximum likelihood and Bayesian methods, and we explored the history of each species via divergence-time estimation based on fossil-calibrations. A variety of ancestral-area reconstruction strategies were employed to estimate past changes of the species' geographical range, and to evaluate the impact of different abiotic barriers on range evolution. We found that frilled swamp treefrogs probably originated in Taiwan or South Vietnam in the Oligocene. Alternatively, the lineage leading to Kurixalus appendiculatus strongly supports a hypothesis of terrestrial connection between the Indian and Asian continents in the Oligocene. The outcome of both our divergence-time estimates and ancestral-area reconstruction suggests that the divergence between species from Indochina and Taiwan can probably be attributed to the opening of the South China Sea, approximately 33 million years ago. We could not find evidence for dispersal between mainland China and Taiwan Island. Formation of both Mekong and Red River valleys did not have any impact on Kurixalus species diversification. However, coincidence in timing of climate change and availability of plausible dispersal routes from the Oligocene to the middle Miocene, plausibly implied that Kurixalus diversification in Asia resulted from contemporaneous, climate-induced environmental upheaval (Late Oligocene Warming at 29 Ma; Mi-1 glaciation since 24.4-21.5 Ma; Mid-Miocene Climatic Optimum at 14 Ma), which alternatively opened and closed dispersal routes.

[Trajectories and Biographical Constellations in a Long-Term Study on Vocational Retraining and their Effects on Return to Work and Sustainable Stay at Work]. / Verlaufskarrieren und biografische Konstellationen beruflicher Rehabilitanden und deren Einflüsse auf Rückkehr und nachhaltigen Verbleib in Arbeit.

OBJEKTIVES: Using qualitative-hermeneutical methods with a focus on biographical (risk-) constellations for conditions of success or failure of return to work - and therefore on the efficiency and sustainability of employment participation benefits - the study accompanies participants during a time span of 2 years after their vocational retraining on their way back into the first labor market. METHODS: The study applies a mixed method design which combines 30 episodical-narrative interviews of participating rehabilitants alongside with a questionnaire survey of a total of 214 participants and 19 interviews of scientists and vocational retraining experts. RESULTS: Overall approximately 80% of the participants of our sample successfully return to work within a period of 18 months. Significant barriers can be illustrated by characteristic risk constellations, which correspond to the following dimensions: occupational choice, coping with illness, the need for protective area beyond the rehabilitation scheme, lack of (typical) life course orientation, lack of acceptance of a transitional phase with lower salary, regional occupation-specific labor market as well as social inclusion and support. CONCLUSION: Qualitative-hermeneutical methods generate - apart from diagnostic attributions and theoretical hypotheses - new factors effective for return to work with importance for rehabilitants; these factors refer to their embeddedness in processes, interrelations and interactions between biography, context factors, and administrative routines. The results identify specific needs for post-rehabilitation services supporting persons with risk constellations.

Phylogenetic analyses of gazelles reveal repeated transitions of key ecological traits and provide novel insights into the origin of the genus Gazella.

African bovids are a famous example of a taxonomic group in which the correlated evolution of body size, feeding mode, gregariousness, and social organization in relation to the preferred habitat type has been investigated. A continuum has been described ranging from small-bodied, sedentary, solitary or socially monogamous, forest- or bush-dwelling, browsing species that seek shelter from predation in dense vegetation, to large-bodied, migratory, highly gregarious, grazing taxa inhabiting open savannahs and relying on flight or group-defense behaviors when facing predators. Here, we examined a geographically widespread clade within the Bovidae (the genus Gazella) that shows minimal interspecific variation in body size and asked if we could still uncover correlated changes of key ecological and behavioral traits during repeated transitions from open-land to mountain-dwelling. Our study used a multi-locus phylogeny (based on sequence variation of Cytb and six nuclear intron markers) of all extant members of the genus Gazella to infer evolutionary patterns of key ecological and behavioral traits and to estimate ancestral character states using Bayesian inference. At the base of the Gazella-phylogeny, open plains were inferred as the most likely habitat type, and three independent transitions toward mountain-dwelling were uncovered. Those shifts coincided with shifts from migratory to sedentary lifestyles. Character estimation for group size was largely congruent with movement patterns in that species forming large groups tended to be migratory, while small group size was correlated with a sedentary lifestyle. Evolutionary patterns of two other conspicuous traits (twinning ability vs. exclusive singleton births and hornless vs. horned females) did not follow this trend in the Gazella-phylogeny. Furthermore, we inferred the genus Gazella to have emerged in the Late Miocene to Pliocene (10-3Mya), and estimating ancestral ranges based on a Dispersal-Extinction-Cladogenesis model found the Middle East to be the most likely origin of the genus.

Multilocus Phylogeny of the Afrotropical Freshwater Crab Fauna Reveals Historical Drainage Connectivity and Transoceanic Dispersal Since the Eocene.

Phylogenetic reconstruction, divergence time estimations and ancestral range estimation were undertaken for 66% of the Afrotropical freshwater crab fauna (Potamonautidae) based on four partial DNA loci (12S rRNA, 16S rRNA, cytochrome oxidase one [COI], and histone 3). The present study represents the most comprehensive taxonomic sampling of any freshwater crab family globally, and explores the impact of paleodrainage interconnectivity on cladogenesis among freshwater crabs. Phylogenetic analyses of the total evidence data using maximum-likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) produced a robust statistically well-supported tree topology that reaffirmed the monophyly of the Afrotropical freshwater crab fauna. The estimated divergence times suggest that the Afrotropical Potamonautidae diverged during the Eocene. Cladogenesis within and among several genera occurred predominantly during the Miocene, which was associated with major tectonic and climatic ameliorations throughout the region. Paleodrainage connectivity was observed with specimens from the Nilo-Sudan and East African coast proving to be sister to specimens from the Upper Guinea Forests in West Africa. In addition, we observed strong sister taxon affinity between specimens from East Africa and the Congo basin, including specimens from Lake Tanganyika, while the southern African fauna was retrieved as sister to the Angolan taxa. Within the East African clade we observed two independent transoceanic dispersal events, one to the Seychelles Archipelago and a second to Madagascar, while we observe a single transoceanic dispersal event from West Africa to São Tomé. The ancestral area estimation suggested a West African/East African ancestral range for the family with multiple dispersal events between southern Africa and East Africa, and between East Africa and Central Africa The taxonomic implications of our results are discussed in light of the widespread paraphyly evident among a number of genera.

Unmasking alpha diversity, cladogenesis and biogeographical patterning in an ancient panarthropod lineage (Onychophora: Peripatopsidae: Opisthopatus cinctipes) with the description of five novel species.

Speciation and biogeographical patterning in the velvet worm Opisthopatus cinctipes was examined under a null hypothesis that numerous discrete lineages are nested within the species. A total of 184 O. cinctipes specimens, together with a single specimen of each of the two congeneric point endemic sister species (O. roseus and O. herbertorum), were collected throughout the forest archipelago in the Eastern Cape, KwaZulu-Natal and Mpumalanga provinces of South Africa. All specimens were sequenced for two partial mitochondrial DNA loci (COI and 12S rRNA), while a single specimen from each locality was sequenced for the nuclear 18S rRNA locus. Evolutionary relationships were assessed using maximum-likelihood and Bayesian inferences, while divergence time estimations were conducted using BEAST. A Bayesian species delimitation approach was undertaken to explore the number of possible novel lineages nested within Opisthopatus, while population genetic structure was examined for the COI locus using ARLEQUIN. Phylogenetic results revealed that O. cinctipes is a species complex comprising seven geographically discrete and statistically well-supported clades. An independent statistical approach to species delimitations circumscribed ca. 67 species. Results from divergence time estimation and rate constancy tests revealed near constant net diversification occurring throughout the Eocene and Oligocene with subdivision of ranges during the Miocene. Gross morphological characters such as leg pair number within O. cinctipes were invariant, while dorsal and ventral integument colour was highly polymorphic. However, scanning electron microscopy revealed considerable differences both between and within clades. The caveats associated with both morphological and algorithmic delineation of species boundaries are discussed. The five novel Opisthopatus species are described.

Ancient animal microRNAs and the evolution of tissue identity.

The spectacular escalation in complexity in early bilaterian evolution correlates with a strong increase in the number of microRNAs. To explore the link between the birth of ancient microRNAs and body plan evolution, we set out to determine the ancient sites of activity of conserved bilaterian microRNA families in a comparative approach. We reason that any specific localization shared between protostomes and deuterostomes (the two major superphyla of bilaterian animals) should probably reflect an ancient specificity of that microRNA in their last common ancestor. Here, we investigate the expression of conserved bilaterian microRNAs in Platynereis dumerilii, a protostome retaining ancestral bilaterian features, in Capitella, another marine annelid, in the sea urchin Strongylocentrotus, a deuterostome, and in sea anemone Nematostella, representing an outgroup to the bilaterians. Our comparative data indicate that the oldest known animal microRNA, miR-100, and the related miR-125 and let-7 were initially active in neurosecretory cells located around the mouth. Other sets of ancient microRNAs were first present in locomotor ciliated cells, specific brain centres, or, more broadly, one of four major organ systems: central nervous system, sensory tissue, musculature and gut. These findings reveal that microRNA evolution and the establishment of tissue identities were closely coupled in bilaterian evolution. Also, they outline a minimum set of cell types and tissues that existed in the protostome-deuterostome ancestor.

Diversification of rhacophorid frogs provides evidence for accelerated faunal exchange between India and Eurasia during the Oligocene.

The accretion of the Indian subcontinent to Eurasia triggered a massive faunal and floral exchange, with Gondwanan taxa entering into Asia and vice versa. The traditional view on the Indian-Asian collision assumes contact of the continental plates during the Early Eocene. Many biogeographic studies rely on this assumption. However, the exact mode and timing of this geological event is still under debate. Here we address, based on an extensive phylogenetic analysis of rhacophorid tree frogs, if there was already a Paleogene biogeographic link between Southeast Asia and India; in which direction faunal exchange occurred between India and Eurasia within the Rhacophoridae; and if the timing of the faunal exchange correlates with one of the recently suggested geological models. Rhacophorid tree frogs showed an early dispersal from India to Asia between 46 and 57 Ma, as reconstructed from the fossil record. During the Middle Eocene, however, faunal exchange ceased, followed by increase of rhacophorid dispersal events between Asia and the Indian subcontinent during the Oligocene that continued until the Middle Miocene. This corroborates recent geological models that argue for a much later final collision between the continental plates. We predict that the Oligocene faunal exchange between the Indian subcontinent and Asia, as shown here for rhacophorid frogs, also applies for other nonvolant organisms with an Indian-Asian distribution, and suggest that previous studies that deal with this faunal interchange should be carefully reinvestigated.

Amphibians crossing the Bering Land Bridge: evidence from holarctic treefrogs (Hyla, Hylidae, Anura).

Based on an updated, time-calibrated phylogeny and applying biogeographical model testing and diversification analysis, we re-examined systematics and biogeography of the Holarctic treefrog genus Hyla with a focus on the East Asian species. We analyzed four mitochondrial genes (12S and 16S rRNA, tRNA(Leu), ND1) and one nuclear gene (POMC) for 192 samples representing 30 species of Hyla. Based on our results we suggest that H. ussuriensis is a synonym of H. japonica. Specimens from Sakhalin and Kunashir Islands might represent a cryptic species within H. japonica. We confirm earlier hypotheses that the genus Hyla originated during the Eocene to Early Oligocene and that Eurasian species originated from two independent dispersal events from North America via the Bering Land Bridge. Middle Eocene to Oligocene dispersal gave rise to the most recent common ancestor of the West Palearctic H. arborea-group and the East Palearctic, newly defined, H. chinensis-group. The Northeast Asian H. japonica-group resulted from a second wave of colonization from the Nearctic. A trans-Atlantic dispersal route could be excluded. Dispersal of the H. arborea-group to the western Palearctic coincides with the closure of the Turgai Strait at the end of the Oligocene. Diversification of Hyla decreased at the end of the Middle Miocene, possibly coinciding with the end of the Mid Miocene Climatic Optimum and the advent of cooler and drier climates in the Northern Hemisphere.

Let's get high: Cladogenesis in freshwater crabs (Decapoda: Potamonautidae: Potamonautes) supports the mountain gradient speciation hypothesis in the Cape Fold and Drakensberg Mountains, South Africa.

During the present study, the evolutionary relationship within a clade of mountain clade of freshwater crabs (Potamonautes) was examined using mtDNA sequence data for species from the Cape Fold Mountain (CFM) and Great Escarpment (Drakensberg Mountain range). We undertook phylogenetic analyses, divergence time estimation, and an ancestral area reconstruction to explore the period of cladogenesis and understand the biogeographic history in this high-altitude clade. Furthermore, we applied four species delimitation methods using ASAP, bPTP, bGMYC, and STACEY on the latter clade. Bayesian phylogenetic analyses retrieved a monophyletic freshwater crab clade comprised of two major sister clades, one comprised of the Cape Fold (clade A) and two comprised of Drakensberg Mountains (clade B) species. Divergence time estimation indicated that the two clades underwent Mio/Pliocene cladogenesis. Within the CFM clade (A), P. amathole (Amathola Mountains) was sister to P. parvispina (Cederberg and Kouebokkeveld Mountains) and the latter species were sister to P. parvicorpus (Cape Peninsula, Jonkershoek, and Helderberg Mountains) sister to P. tuerkayi (Overberg Mountains) and P. brincki (Hottentots Holland Mountains). Within the Drakensberg Mountain clade (B), we observed in situ diversification. Specimens from the southcentral Drakensberg Mountains (Dargle Forest, Injasuti, Karkloof, and Impendle) represent a new undescribed lineage Potamonautes sp. nov. 1. The second clade from the northern Drakensberg, representing P. clarus, was sister to a central Drakensberg Mountain clade that comprised P. depressus that was in turn sister to P. baziya from the Eastern Cape Province. The application of species delimitation methods generally overestimated the number of species. The biogeographic analyses indicated that the Eastern Cape Province is the most likely ancestral range area. Ecological niche modelling of representative species in clades A (Cape Fold Mountains) and B (Drakensberg Mountains) demonstrated that temperature and rainfall were the major abiotic drivers that differentiated the two clades. Our data favours the mountain gradient speciation hypothesis.

Rapid evolution of troglomorphic characters suggests selection rather than neutral mutation as a driver of eye reduction in cave crabs.

This study asked whether reductive traits in cave organisms evolve at a slower pace (suggesting neutral evolution under relaxed selection) than constructive changes, which are likely to evolve under directional selection. We investigated 11 subterranean and seven surface populations of Sundathelphusa freshwater crabs on Bohol Island, Philippines, and examined constructive traits associated with improved food finding in darkness (increased leg and setae length) and reductive traits (reduced cornea size and eyestalk length). All changes occurred rapidly, given that the age of the most recent common ancestor was estimated to be 722-271 ka based on three mitochondrial markers. In order to quantify the speed of character change, we correlated the degree of morphological change with genetic distances between surface and subterranean individuals. The temporal pattern of character change following the transition to subterranean life was indistinguishable for constructive and reductive traits, characterized by an immediate onset and rapid evolutionary change. We propose that the evolution of these reductive traits-just like constructive traits-is most likely driven by strong directional selection.

Identification of transport-critical residues in a folate transporter from the folate-biopterin transporter (FBT) family.

The Synechocystis Slr0642 protein and its plastidial Arabidopsis (Arabidopsis thaliana) ortholog At2g32040 belong to the folate-biopterin transporter (FBT) family within the major facilitator superfamily. Both proteins transport folates when expressed in Escherichia coli. Because the structural requirements for transport activity are not known for any FBT protein, we applied mutational analysis to identify residues that are critical to transport and interpreted the results using a comparative structural model based on E. coli lactose permease. Folate transport was assessed via the growth of an E. coli pabA abgT strain, which cannot synthesize or take up folates or p-aminobenzoylglutamate. In total, 47 residues were replaced with Cys or Ala. Mutations at 22 positions abolished folate uptake without affecting Slr0642 expression in membranes, whereas other mutations had no effect. Residues important for function mostly line the predicted central cavity and are concentrated in the core alpha-helices H1, H4, H7, and H10. The essential residue locations are consistent with a folate-binding site lying roughly equidistant from both faces of the transporter. Arabidopsis has eight FBT proteins besides At2g32040, often lacking conserved critical residues. When six of these proteins were expressed in E. coli or in Leishmania folate or pterin transporter mutants, none showed evidence of folate or pterin transport activity, and only At2g32040 was isolated by functional screening of Arabidopsis cDNA libraries in E. coli. Such negative data could reflect roles in transport of other substrates. These studies provide the first insights into the native structure and catalytic mechanism of FBT family carriers.

Predator-induced changes of female mating preferences: innate and experiential effects.

BACKGROUND: In many species males face a higher predation risk than females because males display elaborate traits that evolved under sexual selection, which may attract not only females but also predators. Females are, therefore, predicted to avoid such conspicuous males under predation risk. The present study was designed to investigate predator-induced changes of female mating preferences in Atlantic mollies (Poecilia mexicana). Males of this species show a pronounced polymorphism in body size and coloration, and females prefer large, colorful males in the absence of predators. RESULTS: In dichotomous choice tests predator-naïve (lab-reared) females altered their initial preference for larger males in the presence of the cichlid Cichlasoma salvini, a natural predator of P. mexicana, and preferred small males instead. This effect was considerably weaker when females were confronted visually with the non-piscivorous cichlid Vieja bifasciata or the introduced non-piscivorous Nile tilapia (Oreochromis niloticus). In contrast, predator experienced (wild-caught) females did not respond to the same extent to the presence of a predator, most likely due to a learned ability to evaluate their predators' motivation to prey. CONCLUSIONS: Our study highlights that (a) predatory fish can have a profound influence on the expression of mating preferences of their prey (thus potentially affecting the strength of sexual selection), and females may alter their mate choice behavior strategically to reduce their own exposure to predators. (b) Prey species can evolve visual predator recognition mechanisms and alter their mate choice only when a natural predator is present. (c) Finally, experiential effects can play an important role, and prey species may learn to evaluate the motivational state of their predators.

Evolution of freshwater crab diversity in the Aegean region (Crustacea: Brachyura: Potamidae).

The aim of this study was to estimate the influence of the palaeogeographic and climatic history of the Aegean region on the diversity of freshwater crabs of the genus Potamon and to test whether this area served as source or reservoir in species diversity. Necessary species delimitation was accomplished by phylogenetic analyses of the mitochondrial markers COX1 and ND1, partial 16S rRNA gene and the tRNALeu gene. We found 14 genetic lineages of which nine could be assigned to previously recognised species. Temporal estimates of the splitting pattern in the phylogeny of Potamon indicated that a combination of geological and climatic events influenced their diversification. Within Potamon, the lineages separated into a western group and an eastern group. This first split in the genus occurred approximately 8.3-5.5 Mya, thus possibly correlated with the Messinian salinity crisis. A likelihood approach to geographic range evolution suggested for most species, occurring in the Aegean area, an origin in the Middle East. Moreover, there were no insular endemics in the central Aegean archipelago, therefore low sea-levels during the Pleistocene glacial periods possibly enabled dispersal to these islands, but subsequent rise in sea-level did not cause speciation. Nevertheless, the diversification of most lineages occurred during the Pleistocene epoch thus coinciding with Quaternary fluctuations of the climate.

Geographical range evolution of the genus Polypedates (Anura: Rhacophoridae) from the Oligocene to present.

Currently, the genus Polypedates comprises 26 species distributed in South, Southeast, and East Asia. Because of their relatively low dispersal capability and intolerance to seawater, this genus is ideal for the study of terrestrial range evolution that extends into the island archipelagos of southeastern Asia. In this study, based on data compiled for Polypedatesfrom previous studies and partial mitochondrial and nuclear genes collected in this study, we performed systematic biogeographical analysis. We confirmed a Sundaland origin for the extant genus and showed northward dispersal into mainland Southeast Asia and Asia, which coincided with the timing of paleoclimatic change from the Oligocene to Middle Miocene. Climate fluctuations had a profound impact on species diversification within the genus Polypedates. Furthermore, the Red River did not mediate species exchange between Southeast Asia and mainland Asia until the end of the Miocene, with the sudden onset of northward dispersal in several clades independently at that time. Alternatively, the lineage of widespread insular P. leucomystaxstrongly supports the hypothesis of terrestrial connection between island archipelagos of Southeast Asia during the Mid-Pleistocene paleoclimate fluctuations. Our biogeographical analysis also supports the recent introduction of P. leucomystax to the Philippines and Ryukyus, as previously suggested.

When Indian crabs were not yet Asian--biogeographic evidence for Eocene proximity of India and Southeast Asia.

BACKGROUND: The faunal and floral relationship of northward-drifting India with its neighboring continents is of general biogeographic interest as an important driver of regional biodiversity. However, direct biogeographic connectivity of India and Southeast Asia during the Cenozoic remains largely unexplored. We investigate timing, direction and mechanisms of faunal exchange between India and Southeast Asia, based on a molecular phylogeny, molecular clock-derived time estimates and biogeographic reconstructions of the Asian freshwater crab family Gecarcinucidae. RESULTS: Although the Gecarcinucidae are not an element of an ancient Gondwana fauna, their subfamily Gecarcinucinae, and probably also the Liotelphusinae, evolved on the Indian Subcontinent and subsequently dispersed to Southeast Asia. Estimated by a model testing approach, this dispersal event took place during the Middle Eocene, and thus before the final collision of India and the Tibet-part of Eurasia. CONCLUSIONS: We postulate that the India and Southeast Asia were close enough for exchange of freshwater organisms during the Middle Eocene, before the final Indian-Eurasian collision. Our data support geological models that assume the Indian plate having tracked along Southeast Asia during its move northwards.

Physiological responses to folate overproduction in Lactobacillus plantarum WCFS1.

BACKGROUND: Using a functional genomics approach we addressed the impact of folate overproduction on metabolite formation and gene expression in Lactobacillus plantarum WCFS1. We focused specifically on the mechanism that reduces growth rates in folate-overproducing cells. RESULTS: Metabolite formation and gene expression were determined in a folate-overproducing- and wild-type strain. Differential metabolomics analysis of intracellular metabolite pools indicated that the pool sizes of 18 metabolites differed significantly between these strains. The gene expression profile was determined for both strains in pH-regulated chemostat culture and batch culture. Apart from the expected overexpression of the 6 genes of the folate gene cluster, no other genes were found to be differentially expressed both in continuous and batch cultures. The discrepancy between the low transcriptome and metabolome response and the 25% growth rate reduction of the folate overproducing strain was further investigated. Folate production per se could be ruled out as a contributing factor, since in the absence of folate production the growth rate of the overproducer was also reduced by 25%. The higher metabolic costs for DNA and RNA biosynthesis in the folate overproducing strain were also ruled out. However, it was demonstrated that folate-specific mRNAs and proteins constitute 8% and 4% of the total mRNA and protein pool, respectively. CONCLUSION: Folate overproduction leads to very little change in metabolite levels or overall transcript profile, while at the same time the growth rate is reduced drastically. This shows that Lactobacillus plantarum WCFS1 is unable to respond to this growth rate reduction, most likely because the growth-related transcripts and proteins are diluted by the enormous amount of gratuitous folate-related transcripts and proteins.