Sahelian woody vegetation in Sénégal

Structure and composition of woody vegetation in Sahelian forest types (not including riparian and riverine types) were studied in Sénégal. The application of classification and ordination resulted in the recognition of seven distinctive woody community types, related to soil and precipitation gradients. The described vegetation types only contained four strictly Saharan species, the rest being of Sahelian and Soudanean affinity, so a floristic change from savanna to desert vegetation after two decades of drought could not be confirmed. Tree density was lower in the northern part than earlier, possibly an indication of degradation. Rejuvenation was greatest at the northernmost arenosolic stations, but low in the southern, ferrouginous areas. This presumably demonstrates the resilience of North-Sahelian vegetation, at the moment being in a dynamic rejuvenation phase, after a period of adverse conditions.     

Biological physics in México

Biological and physical sciences possess a long-standing tradition of cooperativity as separate but related subfields of science. For some time, this cooperativity has been limited by their obvious differences in methods and views. Biological physics has recently experienced a kind of revival (or better a rebirth) due to the growth of molecular research on animate matter. New avenues for research have been opened for both theoretical and experimental physicists. Nevertheless, in order to better travel for such paths, the contemporary biological physicist should be armed with a set of specialized tools and methods but also with a new attitude toward multidisciplinarity. In this review article, we intend to somehow summarize what has been done in the past (in particular, as an example we will take a closer look at the Mexican case), to show some examples of fruitful investigations in the biological physics area and also to set a proposal of new curricula for physics students and professionals interested in applying their science to get a better understanding of the physical basis of biological function.     

Role of Fish in Structuring Invertebrates on Stromatolites in Cuatro Ciénegas, México

Stromatolites, the dominant Precambrian life form, declined in the Phanerozoic to occur today in only a few sites. This decline has been attributed to evolution of metazoan grazers, but stromatolites in our study site, Cuatro Ciénegas, Coahuila, México, harbor diverse macroinvertebrates. Drawing on food chain theory, we hypothesized that fish predation on invertebrates controls invertebrate populations, allowing stromatolites to flourish in Cuatro Ciénegas. Our experiment used small mesh (1 mm) cages to exclude all but larval fishes, and larger (6.5 mm) cages to exclude all larger fishes (including the molluscivorous and omnivorous endemic polymorphic cichlid, Herichthys minckleyi), but allow access to all sizes of the abundant endemic pupfish, Cyprinodon bifasciatus. No effects of treatments on invertebrate densities were noted at 6 week, but significant effects were observed on specific taxonomic groups after 3 month. In absence of fishes, hydrobiidae snails and ceratopogonids increased 3- and 5-fold, respectively, and invertebrate assemblage composition varied among treatments. Algal biomass was not affected by treatments, but algal species composition appeared to change. Overall results suggest that fish assemblages structure invertebrate assemblages, and that fishes may also be factors in determining algal communities.     

Studies on the Flavors in Saké

A very small amount of vanillin was found in Saké, but the mechanism of its formation during Saké brewing has not yet been elucidated. Therefore, shaking culture of a Saké yeast (Kyokai No. 7 strain) was carried out in the Hayduck’s solution containing ferulic acid which was considered to be a precursor of vanillin. By the analysis of the fermentation products, formation of p-hydroxybenzoic acid and vanillic acid was elucidated. On the other hand, in the similar experiment using vanillin in place of ferulic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde and vanillic acid were identified.

On these results, it was suggested that vanillin might be formed as an intermediate of the degradation reaction of ferulic acid, and also, the demethoxylation of vanillin might be occurred in the fermentation of yeast.     

Lévy flights in evolutionary ecology

We are interested in modeling Darwinian evolution resulting from the interplay of phenotypic variation and natural selection through ecological interactions. The population is modeled as a stochastic point process whose generator captures the probabilistic dynamics over continuous time of birth, mutation, and death, as influenced by each individual's trait values, and interactions between individuals. An offspring usually inherits the trait values of her progenitor, except when a random mutation causes the offspring to take an instantaneous mutation step at birth to new trait values. In the case we are interested in, the probability distribution of mutations has a heavy tail and belongs to the domain of attraction of a stable law and the corresponding diffusion admits jumps. This could be seen as an alternative to Gould and Eldredge's model of evolutionary punctuated equilibria. We investigate the large-population limit with allometric demographies: larger populations made up of smaller individuals which reproduce and die faster, as is typical for micro-organisms. We show that depending on the allometry coefficient the limit behavior of the population process can be approximated by nonlinear Lévy flights of different nature: either deterministic, in the form of non-local fractional reaction-diffusion equations, or stochastic, as nonlinear super-processes with the underlying reaction and a fractional diffusion operator. These approximation results demonstrate the existence of such non-trivial fractional objects; their uniqueness is also proved.     

Carotenoids in fish. XXVIII. Carotenoids in Micropterus salmoides (Lalépéde) Centrarchidae

The occurrence and contents of carotenoids in different body parts were investigated by column chromatography and TLC in Micropterus salmoides (Lalép).The following carotenoids were found: -carotene, -cryptoxanthin, -cryptoxanthin, echinenone, canthaxanthin, lutein, zeaxanthin, neothxanthin, tunaxanthin, -doradexanthin, -doradexanthin, idoxanthin, astaxanthin, astaxanthin ester, mutatochrome and mutatoxanthin.Their total contents varied within the range of 0.071–1.691 µg/g wet weight.     

Hormonal changes in spontaneous and aglépristone-induced parturition in dogs

To increase our understanding of the endocrine changes associated with parturition in dogs, plasma concentrations of progesterone (P4), 15-ketodihydroprostaglandin F(2alpha) (PGFM), estradiol-17-beta (E2beta), cortisol, ACTH, prolactin (PRL), LH, and FSH were measured in six spontaneously whelping bitches and in six bitches in which parturition was induced with the progesterone-receptor blocker aglépristone on day 58 of pregnancy. Expulsion of pups in the induced group took place in the presence of P4 concentrations that were still elevated. PGFM concentrations increased before parturition in both groups, but levels were lower in the induced bitches. PGFM levels reached a maximum in both groups during parturition and quickly decreased in the spontaneously whelping group after parturition, but remained elevated in the induced group. In both groups, cortisol concentrations reached similar maximum levels during the last 30 h before the onset of expulsion. During the 3 days postpartum, cortisol concentrations were higher in the induced group. The highly variable ACTH concentrations did not differ significantly throughout the study within or between groups. In both groups, E2beta concentrations decreased and PRL concentrations increased between the late gestational period and the 30-h period before parturition. Concentrations of both LH (spontaneously whelping group) and FSH (both groups) decreased between late gestation and the postpartum period. The results of this study illustrate the hormonal changes around parturition in the bitch, and reveal that aglépristone-induced parturition is associated with still incomplete luteolysis, an altered PGFM profile, and elevated postpartum cortisol concentrations as compared with spontaneously whelping dogs.     

Liste inédite des Reptiles et Amphibiens récoltés par Alcide dˈOrbigny en Amérique méridionale

The complete list of Reptiles and Amphibians collected by dˈOrbigny in South America (Uruguay, Argentina, Chile, Bolivia) is published for the first time. The list consists of six species of Chelonians, 26 of Saurians, 22 of Ophidians and 16 of Amphibians (one Gymnophiona and 15 Anura). In this list, 31 species were new and are still valid. The plates were published separately and prior to the publication of the ‘Reptiles’ chapter in the Voyage dans lˈAmérique méridionale, and sometimes before the corresponding volume of the Erpétologie générale of Duméril and Bibron 〚3〛. The publication dates of the plates change the known name, author(s) and dates of the several figured species.     

Proteomics in Ménière disease

Ménière's disease (MD) is a disorder of the inner ear characterized by an insidious onset and aspecific symptoms, such as dizziness, vertigo, tinnitus, and hearing loss, that may become very debilitating. The presence of endolymphatic hydrops is a common feature in MD patients, but the pathophysiology is still largely unknown. In this study, we have used a proteomics‐driven approach to identify potential biomarkers of MD. To this end, plasma was obtained from whole blood of 16 individuals previously diagnosed as suffering from MD and compared to plasma from healthy donors. A depletion of the highly abundant proteins (i.e., albumin, IgG, transferrin, etc.) was performed in order to enhance the chance of detection of the less represented ones, therefore reducing the noise‐background. Two‐dimensional gel electrophoresis, followed by in‐gel tryptic digestion of the selected spots and LC‐MS/MS analysis, allowed us to identify a set of proteins whose expression appears to be differentially modulated in patients versus controls. In particular: complement factor H and B, fibrinogen alpha and gamma chains, beta‐actin and pigment epithelium derived factor are over expressed; on the other hand, the levels of beta‐2 glycoprotein‐1, vitamin D binding protein and apolipoprotein‐1 are significantly decreased in the plasma of MD‐affected individuals. Even though preliminary and not necessarily linked directly to the molecular pathogenesis of the disease, our original findings suggest that a molecular signature, represented by the plasma protein profile previously described, might represent a potentially powerful, innovative and not invasive tool for early diagnosis and clinical management of MD patients. J. Cell. Physiol. 227: 308–312, 2012. © 2011 Wiley Periodicals, Inc.     

Fissidens monguilloni Thér. in England

Abstract

The 1996 Chagos Expedition provided an opportunity to study the archipelago's bryophyte flora: 25 of the 55 islands were ecologically investigated, some in more detail than others, and lists and representative collections of mosses, hepatics and other cryptogamic plants were assembled for many of them. Although the islands have a low biodiversity for most of these groups, as would be expected in terms of their relatively young age, remoteness and small terrestrial surface areas, those organisms that are present are often found in abundance and play significant ecological roles. Where the status of taxa on islands has been determined, there appears to be a good correlation between bryophyte biodiversity and island size. Epiphytic bryophytes were not host specific and no epiphyllous species was observed. Biogeographic details are provided, where possible, for the 19 taxa recorded, of which four are new to the Indian Ocean and seven are new to the Chagos Archipelago. A new taxon, Cololejeunea planissima var. chagosensis Pócs var. nov. is described, and notes and illustrations of a probably new Lejeunea species are provided.     

Immobilization Results in Sustained Calcium Transport in Nostoc calcicola Bréb

The uptake pattern of Ca²⁺ by the cyanobacterium Nostoc calcicola Bréb in its freely suspended and immobilized form is comprised of two distinct phages; (a) rapid uptake for 1^st 10 min followed by (b) slower transport at least up to 60 min. Entrapment of cyanobacterial cells in polyvinyl foam always maintained a higher Ca²⁺ profile over freely suspended cells. Also, the intracellular Ca²⁺ concentration was three times more in the former under similar experimental conditions. Whereas, illumination supported maximum Ca²⁺ transport in all the sets, darkness resulted in drastic reduction (90%) of Ca²⁺ uptake in freely suspended cells and least (15%) in polyvinyl entrapped cyanobacterial cells. Exogenously added ATP (10 μM) on the other hand, enhanced Ca²⁺ uptake in dark incubated freely suspended cells; ATP at the same concentration failed to bring out any significant enhancement in cation uptake in immobilized cells facing dark exposure. It was observed that these cells were still able to sustain sufficient ATP preserves to drive active transport of Ca²⁺ even in the dark. Furthermore, the immobilized cells exhibited remarkable Ca²⁺ transport rate even at the age of 20 and 50 days at which its free living counterpart took up insignificant Ca²⁺. These findings suggest the improved metabolic efficiency of polyvinyl foam entrapped cells over freely suspended cells in terms of Ca²⁺ accumulation and its possible use as a bioreactor for metal accumulation/removal in repetitive cycles without any measurable loss in cell biomass. Received: 21 May 2001 / Accepted: 27 June 2001     

Impact of Anti-Retroviral Treatment and Cotrimoxazole Prophylaxis on Helminth Infections in HIV-Infected Patients in Lambaréné, Gabon

Background

Foci of the HIV epidemic and helminthic infections largely overlap geographically. Treatment options for helminth infections are limited, and there is a paucity of drug-development research in this area. Limited evidence suggests that antiretroviral therapy (ART) reduces prevalence of helminth infections in HIV-infected individuals. We investigated whether ART exposure and cotrimoxazole preventive therapy (CTX-P) is associated with a reduced prevalence of helminth infections.

Methodology and Principal Findings

This cross-sectional study was conducted at a primary HIV-clinic in Lambaréné, Gabon. HIV-infected adults who were ART-naïve or exposed to ART for at least 3 months submitted one blood sample and stool and urine samples on 3 consecutive days. Outcome was helminth infection with intestinal helminths, Schistosoma haematobium, Loa loa or Mansonella perstans. Multivariable logistic regression was used to assess associations between ART or CTX-P and helminth infection. In total, 408 patients were enrolled. Helminth infection was common (77/252 [30.5%]). Filarial infections were most prevalent (55/310 [17.7%]), followed by infection with intestinal helminths (35/296 [11.8%]) and S. haematobium (19/323 [5.9%]). Patients on CTX-P had a reduced risk of Loa loa microfilaremia (adjusted odds ratio (aOR) 0.47, 95% CI 0.23-0.97, P = 0.04), also in the subgroup of patients on ART (aOR 0.36, 95% CI 0.13-0.96, P = 0.04). There was no effect of ART exposure on helminth infection prevalence.

Conclusions/Significance

CTX-P use was associated with a decreased risk of Loa loa infection, suggesting an anthelminthic effect of antifolate drugs. No relation between ART use and helminth infections was established.     

Summer and winter diapause in pupae of the cabbage butterfly,Pieris melete Ménétriés

The cabbage butterfly, Pieris melete is multivoltine with a pupal summer and winter diapause. Summer and winter diapause are induced principally by relatively long and short daylengths, respectively. The intermediate to relatively short daylengths of autumn permitted some pupae to develop without diapause in the field. A short daylength had a stronger diapause inducing effect than a relatively long one under higher temperatures. The principal sensitive phase for photoperiodic response occurred before the late 3rd larval instar. The critical daylength for wild autumnal populations was between 12h 30min and 12h 40min at an average temperature of 20.5 degrees C. A night interruption by 2h of light averted diapause most effectively when it was placed 10 to 12h after lights-off. High temperatures and long days during summer inhibited the incidence of diapause, suggesting that the occurrence of summer diapause is due to the specific climatic conditions occurring in April and early May, rather than to the high temperatures in summer. This indicates that the butterfly has a cryptic ability to reproduce in summer. High temperatures delayed diapause development, whereas low temperatures enhanced it, indicating that the optimum temperature of diapause development is lower. The diapause regulating mechanisms thus ensure that the species synchronises its development and reproduction with the growth seasons of the host plants and provide the species with a high degree of flexibility in its life cycle.     

Sex differences in Adélie penguin foraging strategies

Consistent sex differences in foraging trip duration, feeding locality and diet of breeding Adélie penguins (Pygoscelis adeliae) were demonstrated at two widely separated locations over several breeding seasons. Differences in foraging behaviour were most pronounced during the guard stage of chick rearing. Female penguins made on average longer foraging trips than males, ranged greater distances more frequently and consumed larger quantities of krill. In contrast, males made shorter journeys to closer foraging grounds during the guard period and fed more extensively on fish throughout chick rearing. Mean guard stage foraging trip durations over four seasons at Béchervaise Island, Eastern Antarctica and over two seasons at Edmonson Point, Ross Sea ranged between 31 and 73 h for females and 25 and 36 h for males. Ninety percent of males tracked from Béchervaise Island by satellite during the first 3 weeks post-hatch foraged within 20 km of the colony, while the majority (60%) of females travelled to the edge of the continental shelf (80–120 km from the colony) to feed during this period. Received: 10 December 1997 / Accepted: 10 April 1998