A contribution to taxonomy and ecology of shrews (Crocidura zimmermanni and C. suaveolens) from Crete and Turkey

Chromosomal and biochemical investigations of shrews from the genus Crocidura from Crete and Turkey show that C. russula monacha Thomas, 1906 and C. caneae Miller, 1909 are both members of the species C. suaveolens Pallas, 1811. C. russula zimmermanni Wettstein, 1953. The population of C. suaveolens in Crete, whose presence on the island dates from at least 3500 years b.p. is biochemically very similar to those of C. suaveolens from Turkey. The same set of electrophoretic data suggests that C. suaveolens from Cyprus became isolated from main land populations much earlier. C. zimmermanni shows closer phylogenetic relationships with C. leucodon and C. suaveolens, than with C. russula. endemic in Crete, C. zimmermanni is syntopic with C, suaveolens at medium and high altitudes, but has been eliminated by the latter in the fertile lowland plains.

Molecular estimation of dispersal for ecology and population genetics

The dispersal process, by which individuals or other dispersing agents such as gametes or seeds move from birthplace to a new settlement locality, has important consequences for the dynamics of genes, individuals, and species. Many of the questions addressed by ecology and evolutionary biology require a good understanding of species' dispersal patterns. Much effort has thus been devoted to overcoming the difficulties associated with dispersal measurement. In this context, genetic tools have long been the focus of intensive research, providing a great variety of potential solutions to measuring dispersal. This methodological diversity is reviewed here to help (molecular) ecologists find their way toward dispersal inference and interpretation and to stimulate further developments.

Ecology and neurophysiology of sleep in two wild sloth species

Study Objectives: Interspecific variation in sleep measured in captivity correlates with various physiological and environmental factors, including estimates of predation risk in the wild. However, it remains unclear whether prior comparative studies have been confounded by the captive recording environment. Herein we examine the impact of predation pressure on sleep in sloths living in the wild. Design: Comparison of two closely related sloth species, one exposed to predation and one free from predation. Setting: Panamanian mainland rainforest (predators present) and island mangrove (predators absent). Participants: Mainland (Bradypus variegatus, 5 males and 4 females) and island (Bradypus pygmaeus, 6 males) sloths. Interventions: None. Measurements and Results: EEG and EMG activity were recorded using a miniature data logger. Although both species spent between 9 and 10 hours per day sleeping, the mainland sloths showed a preference for sleeping at night, whereas island sloths showed no preference for sleeping during the day or night. EEG activity during NREM sleep showed lower low-frequency power, and increased spindle and higher frequency power in island sloths when compared to mainland sloths. Conclusions: In sloths sleeping in the wild, predation pressure influenced the timing of sleep, but not the amount of time spent asleep. The preference for sleeping at night in mainland sloths may be a strategy to avoid detection by nocturnal cats. The pronounced differences in the NREM sleep EEG spectrum remain unexplained, but might be related to genetic or environmental factors.

Cadmium hyperaccumulation and genetic differentiation of Thlaspi caerulescens populations

Although the knowledge on heavy metal hyperaccumulation mechanisms is increasing, the genetic basis of cadmium (Cd) hyperaccurnulation remains to be elucidated. Thlaspi caerulescens is an attractive model since Cd accumulation polymorphism observed in this species suggests genetic differences between populations with low versus high Cd hyperaccumulation capacities. In our study, a methodology is proposed to analyse at a regional scale the genetic differentiation of T. caerulescens natural populations in relation to Cd hyperaccumulation capacity while controlling for different environmental, soil, plant parameters and geographic origins of populations. Twenty-two populations were characterised with AFLP markers and cpDNA polymorphism. Over all loci, a partial Mantel test showed no significant genetic structure with regard to the Cd hyperaccumulation capacity. Nevertheless, when comparing the marker variation to a neutral model, seven AFLP fragments (9% of markers) were identified as presenting particularly high genetic differentiation between populations with low and high Cd hyperaccurnulation capacity. Using simulations, the number of outlier loci was showed to be significantly higher than expected at random. These loci presented a genetic structure linked to Cd hyperaccumulation capacity independently of the geography, environment, soil parameters and Zn, Pb, Fe and Cu concentrations in plants. Using a canonical correspondence analysis, we identified three of them as particularly related to the Cd hyperaccumutation capacity. This study demonstrates that populations with low and high hyperaccurnulation capacities can be significantly distinguished based on molecular data. Further investigations with candidate genes and mapped markers may allow identification and characterization of genomic regions linked to factors involved in Cd hyperaccumulation.

Chemosensory ecology: deceiving Drosophila.

The Solomon's lily arum mimics the odours of yeast to attract drosophilid flies as unrewarded pollinators.

The Crocidura fuliginosa species complex (Mammalia, Insectivora) in Peninsular Malaya: biological, karyological and genetical evidence

Four West Malaysian shrew populations of the genus Crocidura were investigated through their karyotype and allozyme variations, and, in part, by interfertility experiments. Two different karyotypes characterize these shrews. The first, restricted to the Cameron Highlands (Peninsular Malaysia), invariably has 2n = 40 chromosomes but a varying fundamental number (FN = 54-58). The second karyotype shows a fundamental number of 62-68 and a polymorphic chromosomal number of 2n = 38, 39 or 40, a rare event in the genus Crocidura. Thus both can be distinguished by either a low or a higher number of meta- and submetacentric elements. In heterospecific breeding experiments, mutual avoidance was observed suggesting prezygotic barriers, whereas intraspecific pairs produced 13 liters (mean 2.1 young). Furthermore, our biochemical results indicate that both karyotypes correspond to a relatively ancient separation (Nei's D = 0.354), an amount of genetic differentiation comparable to the distance separating them from the West Palearctic C. russula (D = 0.429-0.583). In contrast, conspecific island and mainland Malaysian shrews possessing the second karyotype had only one fixed allelic difference over the 35 loci surveyed. The problem of naming the two biological species remains unsolved and requires further comparative investigations.

Evolutionary ecology of learning: insights from fruit flies

Ecologically and evolutionarily oriented research on learning has traditionally been carried out on vertebrates and bees. While less sophisticated than those animals, fruit flies (Drosophila) are capable of several forms of learning, and have an advantage of a short generation time, which makes them an ideal system for experimental evolution studies. This review summarizes the insights into evolutionary questions about learning gained in the last decade from evolutionary experiments on Drosophila. These experiments demonstrate that Drosophila have the genetic potential to evolve substantially improved learning performance in ecologically relevant learning tasks. In at least one set of selected populations the improved learning generalized to another task than that used to impose selection, involving a different behavior, different stimuli, and a different sensory channel for the aversive reinforcement. This improvement in learning ability was associated with reduction in other fitness-related traits, such as larval competitive ability and lifespan, pointing out to evolutionary trade-offs of improved learning. These trade-offs were confirmed by other evolutionary experiments where reduction in learning performance was observed as a correlated response to selection for tolerance to larval nutritional stress or for delayed aging. Such trade-offs could be one reason why fruit flies have not fully used up their evolutionary potential for learning ability. Finally, another evolutionary experiment with Drosophila provided the first direct evidence for the long-standing ideas that learning can under some circumstances accelerate and in other slow down genetically-based evolutionary change. These results demonstrate the usefulness of fruit flies as a model system to address evolutionary questions about learning.

Blood, urine and vitreous isopropyl alcohol as biochemical markers in forensic investigations.

Isopropyl alcohol (IPA) is widely used as an industrial solvent and cleaning fluid. After ingestion or absorption, IPA is converted into acetone by alcohol dehydrogenase. However, in ketosis, acetone can be reduced to IPA. The aim of this study was to investigate blood IPA and acetone concentrations in a series of 400 medico-legal autopsies, including cases of diabetic ketoacidosis, hypothermia and alcohol misuse-related deaths, to illustrate the extent of ketosis at the time of death. Vitreous glucose, blood 3-β-hydroxybutyrate (3HB) and acetoacetate (AcAc) concentrations were also determined systematically. Additionally, vitreous and urine IPA, acetone, 3HB and AcAc concentrations as well as other biochemical markers, including glycated hemoglobin and carbohydrate-deficient transferrin (CDT) were also determined in selected cases. The results of this study indicate that ketosis is characterized by the presence of IPA resulting from the acetone metabolism and that IPA can be detected in several substrates. These findings confirm the importance of the systematic determination of IPA and acetone levels that is used to quantify biochemical disturbances and the importance of ketosis at the time of death.

Biochemical analysis of female mice urine with reference to endocrine function: a key tool for estrus detection.

Species-specific chemical signals released through urine, sweat, saliva and feces are involved in communication between animals. Urinary biochemical constituents along with pheromones may contribute to variation across reproductive cycles and facilitate to estrus detection. Hence, the present study was designed to analyze such biochemical profiles, such as proteins, carbohydrates, lipids, fatty acids, in response with steroid hormones such as estradiol and progesterone. The experimental groups were normal, prepubertal, ovariectomized, and ovariectomized with estrogentreated female mice. In normal mice, the protein and lipid concentrations in urine were significantly higher in proestrus and estrus phases and the quantity of fatty acids was also comparatively higher in estrus. Furthermore, certain fatty acids, namely tridecanoic, palmitic and oleic acids, were present during proestrus and estrus phases, but were exclusively absent in ovariectomized mice. However, the carbohydrate level was equally maintained throughout the four phases of estrous cycle. For successful communication, higher concentrations of protein and specific fatty acids in estrus are directly involved. The significant increase in estradiol at estrus and progesterone at metestrus seems to be of greater importance in the expression pattern of biochemical constituents and may play a notable role in estrous cycle regulation. Thus, we conclude that the variations observed in the concentration of the biochemical constituents depend on the phase of the reproductive cycle as well as hormonal status of animals. The appearance of protein and specific fatty acids during estrus phase raises the possibility to use these as a urinary indicators for estrus detection.

Expression, purification and biochemical characterization of recombinant Ca-dependent protein kinase 2 of the malaria parasite Plasmodium falciparum.

Calcium-dependent protein kinases (CDPKs) are serine/threonine kinases that react in response to calcium which functions as a trigger for several mechanisms in plants and invertebrates, but not in mammals. Recent structural studies have defined the role of calcium in the activation of CDPKs and have elucidated the important structural changes caused by calcium in order to allow the kinase domain of CDPK to bind and phosphorylate the substrate. However, the role of autophosphorylation in CDPKs is still not fully understood. In Plasmodium falciparum, seven CDPKs have been identified by sequence comparison, and four of them have been characterized and assigned to play a role in parasite motility, gametogenesis and egress from red blood cells. Although PfCDPK2 was already discovered in 1997, little is known about this enzyme and its metabolic role. In this work, we have expressed and purified PfCDPK2 at high purity in its unphosphorylated form and characterized its biochemical properties. Moreover, propositions about putative substrates in P. falciparum are made based on the analysis of the phosphorylation sites on the artificial substrate myelin basic protein (MBP).