Mitochondrial phylogeny of African wood mice, genus Hylomyscus (Rodentia, Muridae): implications for their taxonomy and biogeography

This paper investigates the usefulness of two mitochondrial genes (16S rRNA and cytochrome b) to solve taxonomical difficulties within the genus Hylomyscus and to infer its evolutionary history. Both genes proved to be suitable molecular markers for diagnosis of Hylomyscus species. Nevertheless the resolving powers of these two genes differ, and with both markers (either analyzed singly or in combination), some nodes remain unresolved. This is probably related to the fact that the species emerged during a rapid diversification event that occurred 2-6 Myr ago (4-5 Myr ago for most divergence events). Our molecular data support the recognition of an "aeta" group, while the "alleni" and "parvus" groups are not fully supported. Based on tree topology and genetic divergence, two taxa generally recognized as subspecies should be elevated at the species level (H. simus and H. cf kaimosae). H. stella populations exhibit ancient haplotype segregation that may represent currently unrecognized allopatric species. The existence of cryptic species within H. parvus is questioned. Finally, three potentially new species may occur in West Central Africa. The Congo and Oubangui Rivers, as well as the Volta and Niger Rivers and/or the Dahomey gap could have formed effective barriers to Hylomyscus species dispersal, favoring their speciation in allopatry. The pronounced shifts in African climate during the late Pliocene and Miocene, which resulted in major changes in the distribution and composition of the vegetation, could have promoted speciation within the genus (refuge theory). Future reports should focus on the geographic distribution of Hylomyscus species in order to get a better understanding of the evolutionary history of the genus.     

Biogeographic origin and radiation of Cuban Eleutherodactylus frogs of the auriculatus species group,inferred from mitochondrial and nuclear gene sequences

We studied phylogenetic relationships of the Eleutherodactylus auriculatus species group to infer colonization and diversification patterns in this endemic radiation of terrestrial frogs of the genus Eleutherodactylus in the largest of the Greater Antilles, Cuba. An initial screening of genetic diversity based on partial sequences of the 16S rRNA gene in almost 100 individuals of all species of the group and covering the complete known geographic range of their occurrence found most species endemic to small ranges in the eastern Cuban mountains while a single species was widespread over most of Cuba. Our molecular phylogeny, based on 3731 bp of four mitochondrial and one nuclear gene, suggests that most cladogenetic events within the group occurred among clades restricted to the eastern mountains, which acted as refugia and facilitated the diversification in this group. Our results reveal two separate colonization events of Central and Western Cuba and allow inferring the timing of the subsequent diversification events that occurred between 11 and 2 Mya. Because populations previously assigned to E. auriculatus represent four genetically strongly divergent lineages that also differ in their advertisement calls, we propose that E. auriculatus as currently recognized comprises four species. The difficulties in assigning the name auriculatus to any of these four species, and the fact that E. principalis is nested within one of them, stress the need for a thorough taxonomic revision of this group.     

Seed banks of temperate deciduous forests during secondary succession

Question: (i) How does former land use and land use intensity affect seed bank development during post‐agricultural succession? (ii) How does time since the last clear‐cut change seed bank composition during post‐clear‐cut succession? Methods: One data set was compiled per succession type using the following selection criteria: (i) the data set included a successional series, (ii) plots were located in mesotrophic forest plant communities and (iii) vegetation data were available. The post‐agricultural succession data set comprised 76 recent forest plots (eight studies); the post‐clear‐cut succession data set comprised 218 ancient forest plots (three studies). Each data set was analysed separately using either linear mixed models or generalized linear models, controlling for both environmental heterogeneity and variation between study locations. Results: In the post‐agricultural succession data set, land use and time significantly affected nearly all the studied seed bank characteristics. Seed banks on former arable land recovered poorly even after 150 year of restored forest cover, whereas moderate land use intensities (grasslands, heathlands) yielded more rapid seed bank recovery. Time was a significant determinant of all but two soil seed bank characteristics during post‐clear‐cut succession. Seed banks in managed ancient forest differed strongly in their characteristics compared to primary forest seed banks. Conclusions: Forest seed banks bear the marks of former land use and/or forest management and continue to do so for at least 150 years. Nevertheless, time since the last major disturbance, being either former land use or clear‐cutting, remains a significant determinant of the seed bank.     

Detection of Adenoviruses and Rotaviruses in Drinking Water Sources Used In Rural Areas of Benin,West Africa

Diseases associated with viruses also found in environmental samples cause major health problems in developing countries. Little is known about the frequency and pattern of viral contamination of drinking water sources in these resource-poor settings. We established a method to analyze 10 liters of water from drinking water sources in a rural area of Benin for the presence of adenoviruses and rotaviruses. Overall, 541 samples from 287 drinking water sources were tested. A total of 12.9% of the sources were positive for adenoviruses and 2.1% of the sources were positive for rotaviruses at least once. Due to the temporary nature of viral contamination in drinking water sources, the probability of virus detection increased with the number of samples taken at one test site over time. No seasonal pattern for viral contaminations was found after samples obtained during the dry and wet seasons were compared. Overall, 3 of 15 surface water samples (20%) and 35 of 247 wells (14.2%) but also 2 of 25 pumps (8%) tested positive for adenoviruses or rotaviruses. The presence of latrines within a radius of 50 m in the vicinity of pumps or wells was identified as being a risk factor for virus detection. In summary, viral contamination was correlated with the presence of latrines in the vicinity of drinking water sources, indicating the importance of appropriate decision support systems in these socioeconomic prospering regions.Although access to safe drinking water is considered a human right, many people suffer from inadequate water supply. Especially in developing countries, improper water quality causes major public health problems affecting mortality rates in highly susceptible people (small children and immunocompromised patients) as well as economic income problems due to disease-related nonproductive time. Only 37.4% of households have access to piped water sources in Benin, West Africa, and in rural areas, even fewer have access (3). Many diseases like diarrhea, gastroenteritis, keratoconjunctivitis, respiratory infections, and hepatitis are associated with viruses, often found in environmental samples like groundwater, surface water, sewage, costal water, shellfish, and tap water (5, 6, 10, 13, 23, 38). Virus concentrations in environmental samples are low both due to the inability to replicate without a host cell and because of continuous degradation and dilution effects. On the other hand and in contrast to most bacterial infections, even small amounts of viruses (as few as 10 PCR-detectable units) are sufficient to establish an infection in the new host (24). Bacterial indicators seem to be inappropriate for analyzing viral contamination, since viruses are more resistant to environmental conditions (2) and spread over a longer distance than bacteria (9). Therefore, viruses are often found without any bacterial indicator for fecal contamination (2, 6). In North America, 15 to 30% of all gastrointestinal diseases were suspected of being related to water (30), whereas worldwide, over 88% of diarrheal diseases are waterborne or water related (18).Routine screening of environmental samples for viral contamination is controversially being discussed at the moment. Furthermore, no standard procedure for the detection of viruses in environmental samples currently exists. In numerous studies, virus concentration from water was achieved by filtration using electropositive filters (1MDS) (12, 15, 25, 26, 33). Further methods using ultrafiltration, glass wool filters (7, 22), or immunomagnetic separation (16, 28) were used to detect small amounts of viruses independently of matrix effects. However, the U.S. Environmental Protection Agency listed adenovirus as one of nine microorganisms on the contamination candidate list for drinking water as a potential indicator virus due to an outstanding resistance to UV disinfection. The 51 presently recognized adenovirus serotypes are responsible for a great variety of human diseases like diarrhea, keratoconjunctivitis, and respiratory infections. However, severe diarrhea, especially in small children and immunocompromised patients, is often caused by rotaviruses. The fatal outcome of infant diarrhea substantially contributes to the high mortality rate of children under the age of 5 years in developing countries (8). In Benin, the probability of dying per 1,000 live births under 5 years of age (under-5 mortality rate) was 152 in 2004, and 17.1% of these deaths were caused by diarrheal diseases (37). To address the frequency and pattern of viral contamination in drinking water sources in rural areas of West Africa, we analyzed water samples during the dry and wet seasons in Benin for contamination with adenoviruses as indicators and rotaviruses as important pathogens in developing countries.     

Processing and selection of surgically-retrieved sperm for ICSI: a review

Although the technique of intracytoplasmic sperm injection (ICSI) has been a revolution in the alleviation of male infertility, the use of testicular sperm for ICSI was a formerly unseen breakthrough in the treatment of the azoospermic man with primary testicular failure. At the clinical level, different procedures of testicular sperm retrieval (conventional TESE, micro-TESE, FNA/TESA, MESA, PESA) are being performed, the choice is mainly based on the cause of azoospermia (obstructive versus non-obstructive) and the surgeon’s skills. At the level of the IVF laboratory, mechanical procedures to harvest the sperm from the tissue may be combined with enzymatic treatment in order to increase the sperm recovery rates. A number of techniques have been developed for viable sperm selection in males with only immotile testicular sperm available. However, large, well-designed studies on the benefit and safety of one over the other technique are lacking. Despite all the available methods and combinations of laboratory procedures which have a common goal to maximize sperm recovery from testicular samples, a large proportion of NOA patients fail to father a genetically own child. Advanced technology application may improve recovery rates by detection of the testicular foci with active spermatogenesis and/or identification of the rare individual sperm in the testicular suspensions. On the other hand, in vitro spermatogenesis or sperm production from embryonic stem cells or induced pluripotent stem cells might be future options. The present review summarizes the available strategies which aim to maximize sperm recovery from surgically retrieved samples.     

Drivers affecting habitat use in Afrotropical hipposiderid and pteropodid bats

Assessing how bats respond to habitat attributes requires an integrative approach to reliably predict direct community-level effects. We focused on hipposiderid and pteropodid bats because of their diverse resource use patterns, body size ranges, and dispersal abilities. We combined an array of bat species-level characteristics with key forest stand characteristics that may covary with habitat use. Twelve stations were sampled in the Lomami and Yangambi landscapes, Democratic Republic of the Congo. We investigated whether species-level flight ability of bats and forest stand characteristics can affect bat commuting flights and community-level estimates of both species detection and habitat occupancy. We captured bats for 108 trap-nights. Three sampling events (early evening, middle of the night, and early morning) were replicated for each survey night. Hipposiderids showed an early evening flight peak, while flight activity of pteropodids was constant throughout the night, but increased around the middle of the night. Species capture probability decreased with higher wing loading in hipposiderids and was negatively correlated with higher wing aspect ratio in pteropodids. Forest occupancy of hipposiderids increased along the gradient towards waterways, while pteropodid occurrence was not directly linked to measured forest stand variables. This suggests a consequence of habitat patterns at larger spatial scales, which would need clarifying through additional data collection. We discuss these findings in terms of resource-use strategies of clutter-tolerant and clutter-intolerant species. We argue that the occurrence of specific bat species and their habitat use patterns can serve as surrogate measures of ecosystem health.     

Distribution, population dynamics and habitat use of the lesser pouched rat, Beamys hindei

The lesser pouched rat, Beamys hindei Thomas 1909, is one of Africa's rarest and least known rodents, recorded only from a few localities in Kenya and Tanzania. The results of this study show that B. hindei is more widely distributed than previously thought and occurs at high densities in suitable habitat. It breeds throughout the year, but maintains relatively constant population densities as recruitment rates are low. On account of its ability to cache food, it is well adapted to seasonally dry forests where food is in short supply for part of the year. The need for suitable soil in which to construct its burrows and dense vegetation cover may partly account for its patchy distribution. Morphological data collected during this study provide no evidence for separating B. hindei from B. major and suggest that the differences previously recorded between the two forms may be actually due to clinal variation in size from north to south.     

Biphasic response of intimal prostacyclin production during the development of experimental atherosclerosis

Feeding a cholesterol rich diet (0.3%) to rabbits for up to 10 weeks resulted in morphological changes of the vascular wall. Microscopic evaluation of the aorta revealed a lipid infiltration and an intimal thickening containing foam cells, which both became more pronounced as the cholesterol feeding was more prolonged. The intimal prostacyclin production showed a transient increase after 2 weeks, but was significantly decreased after 6 weeks of diet and remained at this low level during the rest of the experiment. No significant changes in formation of thromboxane B2 by the platelets could be observed, whereas the production of 12-HETE was enhanced.