Teaching animal habitat selection using wildlife tracking equipment

We present a hands-on outdoor activity coupled with classroom discussion to teach students about wildlife habitat selection, the process by which animals choose where to live. By selecting locations or habitats with many benefits (e.g., food, shelter, mates) and few costs (e.g., predators), animals improve their ability to survive and reproduce. Biologists track animal movement using radio telemetry technology to study habitat selection so they can better provide species with habitats that promote population growth. We present a curriculum in which students locate “animals” (transmitters) using radio telemetry equipment and apply math skills (use of fractions and percentages) to assess their “animal's” habitat selection by comparing the availability of habitat types with the proportion of “animals” they find in each habitat type.     

The oil of Adenanthera pavonina L. seeds and its emulsions

The oil of Adenanthera pavonina L. seeds was analysed by chromatographic and instrumental means. The oil was found to be rich in neutral lipids (86.2%), and low in polar lipids (13.8%). The neutral lipids consisted mainly of triacylglycerols (64.2%). Unsaturated fatty acids were found as high as 71%, while the percentage of saturated fatty acids was only 29%. GC and GC/MS analyses revealed linoleic, oleic and lignocerotic acid to be predominant among all fatty acids in the A. pavonina oil, whereas stigmasterol was the major steroid identified within this study. Subsequently, the oil was used for preparation of submicron oil-in-water (o/w) lipid emulsions. Lipid emulsions were formulated by using soybean lecithin (SL) to investigate their particle size, Zeta potential and stability at the different oil and SL ratios. The results obtained indicate possible applications of the tested oil in pharmaceutical and medical fields as drug and cosmetic active ingredient carriers.     

Gramicidin S Synthetase,an Enzyme with an Unusually Large Number of Catalytic Functions

THE biosynthesis of gramicidin S consists in joining five different amino-acids, each occurring twice, into the cyclic structure: illustration

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Usefulness of linked DNA probes for prenatal diagnosis of cystic fibrosis: report of a case in a 1:4 risk pregnancy

Prenatal diagnosis of cystic fibrosis was performed with linked DNA probes in a couple with a 1:4 risk. The limits and the future of molecular prenatal diagnosis are discussed.     

Age-dependent changes in the in-vitro response of a pig Sertoli cell-enriched population to FSH

The response of pig Sertoli cell-enriched cultures to FSH was investigated by measuring plasminogen activator (PA) secretion in culture, throughout the nonpubertal and prepubertal periods. Sertoli cell-enriched populations could be isolated from birth until a testicular weight of 56 g. FSH elicited a dose-dependent increase in PA secretion by pig Sertoli cell-enriched cultures. The ED50 was minimal for cells coming from testes weighing 10-22 g, and increased more than 2-fold for cells from heavier testes. This suggests that, at the end of the non-pubertal period, an increased FSH sensitivity is important for initiation of spermatogenesis in this species, and that during the prepubertal period Sertoli cells become less sensitive to FSH. The FSH-stimulated PA secretion increased about 10-fold from a testicular weight of 25 g onwards, i.e. when primary spermatocytes appear in seminiferous tubules.     

The fast milk acidifying phenotype of Streptococcus thermophilus can be acquired by natural transformation of the genomic island encoding the cell-envelope proteinase PrtS

Background

FAD dependent glucose dehydrogenase (GDH) currently raises enormous interest in the field of glucose biosensors. Due to its superior properties such as high turnover rate, substrate specificity and oxygen independence, GDH makes its way into glucose biosensing. The recently discovered GDH from the ascomycete Glomerella cingulata is a novel candidate for such an electrochemical application, but also of interest to study the plant-pathogen interaction of a family of wide-spread, crop destroying fungi. Heterologous expression is a necessity to facilitate the production of GDH for biotechnological applications and to study its physiological role in the outbreak of anthracnose caused by Glomerella (anamorph Colletotrichum) spp.

Results

Heterologous expression of active G. cingulata GDH has been achieved in both Escherichia coli and Pichia pastoris, however, the expressed volumetric activity was about 4800-fold higher in P. pastoris. Expression in E. coli resulted mainly in the formation of inclusion bodies and only after co-expression with molecular chaperones enzymatic activity was detected. The fed-batch cultivation of a P. pastoris transformant resulted in an expression of 48,000 U L^-1 of GDH activity (57 mg L^-1). Recombinant GDH was purified by a two-step purification procedure with a yield of 71%. Comparative characterization of molecular and catalytic properties shows identical features for the GDH expressed in P. pastoris and the wild-type enzyme from its natural fungal source.

Conclusions

The heterologous expression of active GDH was greatly favoured in the eukaryotic host. The efficient expression in P. pastoris facilitates the production of genetically engineered GDH variants for electrochemical-, physiological- and structural studies.     

The postcranial anatomy of Suminia getmanovi (Synapsida: Anomodontia), the earliest known arboreal tetrapod

The basal anomodont Suminia getmanovi Ivakhnenko, 1994 from the late Palaeozoic of Russia is highly specialized in its masticatory apparatus, and has been suggested to represent the earliest arboreal tetrapod in the fossil record. Its postcranial anatomy is described in detail for the first time, revealing a large number of autapomorphies for this small herbivore. These include a reduced number of presacral and therein dorsal vertebrae, an elongate neck, a long and possibly prehensile tail, a procoracoid with a notch at its ventromedial margin rather than a foramen, an iliac blade with a robust ridge at its anteromedial edge, a pubis with a puboischiadic fenestra and separate pubic foramen, and elongate limbs. Additional autapomorphic characters are displayed in the autopodium, which comprises about 40% of the entire limb length. These features include an enlarged, phalangiform distal carpal 1 and tarsal 1, a short and robust first metacarpal, a crescent‐shaped distal tarsal 4, and elongate penultimate phalangeal elements. The phylogenetic relationships of basal anomodonts are revisited using an expanded data set, with the addition of key taxa and several postcranial characters. Unlike dicynodonts, Suminia retained the plesiomorphic phalangeal formula for amniotes of 2‐3‐4‐5‐3 (manus) and 2‐3‐4‐5‐4 (pes). This pattern is achieved by the retention of disc‐like phalangeal elements between the proximal and penultimate phalanges in digits III, IV (manus and pes), and V (pes only). In light of the new material, Suminia can be recognized as the most complete basal anomodont, offering new insights into the early evolution of the group. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 661–698.     

Key Features of Intertidal Food Webs That Support Migratory Shorebirds

The migratory shorebirds of the East Atlantic flyway land in huge numbers during a migratory stopover or wintering on the French Atlantic coast. The Brouage bare mudflat (Marennes-Oléron Bay, NE Atlantic) is one of the major stopover sites in France. The particular structure and function of a food web affects the efficiency of carbon transfer. The structure and functioning of the Brouage food web is crucial for the conservation of species landing within this area because it provides sufficient food, which allows shorebirds to reach the north of Europe where they nest. The aim of this study was to describe and understand which food web characteristics support nutritional needs of birds. Two food-web models were constructed, based on in situ measurements that were made in February 2008 (the presence of birds) and July 2008 (absence of birds). To complete the models, allometric relationships and additional data from the literature were used. The missing flow values of the food web models were estimated by Monte Carlo Markov Chain – Linear Inverse Modelling. The flow solutions obtained were used to calculate the ecological network analysis indices, which estimate the emergent properties of the functioning of a food-web.The total activities of the Brouage ecosystem in February and July are significantly different. The specialisation of the trophic links within the ecosystem does not appear to differ between the two models. In spite of a large export of carbon from the primary producer and detritus in winter, the higher recycling leads to a similar retention of carbon for the two seasons. It can be concluded that in February, the higher activity of the ecosystem coupled with a higher cycling and a mean internal organization, ensure the sufficient feeding of the migratory shorebirds.     

Dimeric transferrin inhibits phagocytosis of residual bodies by testicular rat Sertoli cells

Transferrin is well known as an iron transport glycoprotein. Dimeric or tetrameric transferrin forms have recently been reported to modulate phagocytosis by human leukocytes. It is mainly synthesized by the liver, and also by other sources, such as Sertoli cells of the testis. Sertoli cells show a strong phagocytic activity toward apoptotic germ cells and residual bodies. Here, we provide evidence that purified human dimeric transferrin from commercial sources decreased residual body phagocytosis, unlike monomeric transferrin. The presence of iron appeared essential for dimeric transferrin inhibitory activity. Importantly, dimeric transferrin could be visualized by immunoblotting in Sertoli cell lysates as well as in culture media, indicating that dimeric transferrin could be physiologically secreted by Sertoli cells. By siRNA-mediated knockdown, we show that endogenous transferrin significantly inhibited residual body ingestion by Sertoli cells. These results are the first to identify dimeric transferrin in Sertoli cells and to demonstrate its implication as a physiological modulator of residual body phagocytosis by Sertoli cells.