Nile crocodiles, Crocodylus niloticus, and estuarine crocodiles, Crocodylus porosus, show similar osmoregulatory responses on exposure to seawater

1. Nile crocodiles, reared in fresh water and exposed acutely to seawater, suffer marked dehydration and hypernatraemia. Cloacal urine osmolarity and potassium concentration increased markedly but urine sodium remains low. 2. Hypernatraemia is increased when secretion from the lingual salt glands is prevented. 3. C. niloticus appears not to drink seawater. 4. Similarities in osmoregulatory response between estuarine and Nile crocodiles suggest that the lingual salt glands of C. niloticus are functional in salt water, playing an important role in sodium balance. 5. Significant differences in the function of the renal/cloacal complex of Alligator and Crocodylus emphasize further the differences between these two groups of crocodilian and provide support for the postulated marine ancestry of many or all of the Crocodylidae.     

Identification of a CA repeat at the TCRA locus using yeast artificial chromosomes: a general method for generating highly polymorphic markers at chosen loci.

The creation of a comprehensive genetic map in human has been limited by the lack of highly polymorphic markers spaced evenly throughout the human genome. We have utilized yeast artificial chromosomes (YAC) containing large human DNA inserts to help identify highly polymorphic (CA)n repeats at a chosen locus. The DNA of a YAC containing the locus was subcloned in M13 vectors, and the recombinants were screened at high stringency to detect preferentially long (CA)n repeats (n greater than 20). These repeats, which are the most likely to be highly polymorphic, were then studied to confirm both the level of polymorphism and their precise genetic location. This strategy has permitted the identification of a new, highly polymorphic CA repeat (77% heterozygosity) at the T cell receptor alpha chain (TCRA) locus on chromosome 14q. It provides a powerful marker for assessing the role of this locus in the susceptibility to autoimmune and infectious diseases. This approach should permit the development of highly polymorphic markers at any targeted locus and rapidly improve the current human genetic map.     

1H, 13C and 15N chemical shift assignments of unliganded Bcl-xL and its complex with a photoresponsive Bak-derived peptide

Here we report the ¹H, ¹³C and ¹⁵N resonance assignments of free Bcl-x_L and of Bcl-x_L in complex with an azobenzene-modified peptide derived from the BH3 domain of the pro-apoptotic Bak. The spectra suggest predominantly folded proteins; chemical shift difference analysis provides a detailed view of the reorganization occurring on peptide binding.     

Seasonal Diet and Prey Preference of the African Lion in a Waterhole-Driven Semi-Arid Savanna

Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs’ index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group “medium Bovidae” are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs’ index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.     

Fungal bioremediation of polyethylene: Challenges and perspectives

Plastics have become ubiquitous in both their adoption as materials and as environmental contaminants. Widespread pollution of these versatile, man-made and largely petroleum-derived polymers has resulted from their long-term mass production, inappropriate disposal and inadequate end of life management. Polyethylene (PE) is at the forefront of this problem, accounting for one-third of plastic demand in Europe in part due to its extensive use in packaging. Current recycling and incineration processes do not represent sustainable solutions to tackle plastic waste, especially once it becomes littered, and the development of new waste-management and remediation technologies are needed. Mycoremediation (fungal-based biodegradation) of PE has been the topic of several studies over the last two decades. The utility of these studies is limited by an inconclusive definition of biodegradation and a lack of knowledge regarding the biological systems responsible. This review highlights relevant features of fungi as potential bioremediation agents, before discussing the evidence for fungal biodegradation of both high- and low-density PE. An up-to-date perspective on mycoremediation as a future solution to PE waste is provided.     

Trophoblast–endothelium signaling involves angiogenesis and apoptosis in a dynamic bioprinted placenta model

Trophoblast invasion and remodeling of the maternal spiral arteries are required for pregnancy success. Aberrant endothelium–trophoblast crosstalk may lead to preeclampsia, a pregnancy complication that has serious effects on both the mother and the baby. However, our understanding of the mechanisms involved in this pathology remains elementary because the current in vitro models cannot describe trophoblast–endothelium interactions under dynamic culture. In this study, we developed a dynamic three-dimensional (3D) placenta model by bioprinting trophoblasts and an endothelialized lumen in a perfusion bioreactor. We found the 3D printed perfusion bioreactor system significantly augmented responses of endothelial cells by encouraging network formations and expressions of angiogenic markers, cluster of differentiation 31 (CD31), matrix metalloproteinase-2 (MMP2), matrix metalloproteinase-9 (MMP9), and vascular endothelial growth factor A (VEGFA). Bioprinting favored colocalization of trophoblasts with endothelial cells, similar to in vivo observations. Additional analysis revealed that trophoblasts reduced the angiogenic responses by reducing network formation and motility rates while inducing apoptosis of endothelial cells. Moreover, the presence of endothelial cells appeared to inhibit trophoblast invasion rates. These results clearly demonstrated the utility and potential of bioprinting and perfusion bioreactor system to model trophoblast–endothelium interactions in vitro. Our bioprinted placenta model represents a crucial step to develop advanced research approach that will expand our understanding and treatment options of preeclampsia and other pregnancy-related pathologies.     

The DAZL family proteins are PABP-binding proteins that regulate translation in germ cells

DAZL proteins are germ-cell-specific RNA-binding proteins essential for gametogenesis. The precise molecular role of these proteins in germ-cell development remains enigmatic; however, they appear to function in the cytoplasm. In order to directly address the function of vertebrate DAZL proteins, we have used Xenopus laevis oocytes as a model system. Here we demonstrate that members of this family, including Xdazl, mouse Dazl, human DAZL, human DAZ and human BOULE, have the ability to stimulate translation and function at the level of translation initiation. We show that DAZL proteins interact with poly(A)-binding proteins (PABPs), which are critical for the initiation of translation. Mapping and tethered function experiments suggest that these interactions are physiologically important. This leads to an attractive hypothesis whereby DAZL proteins activate translationally silent mRNAs during germ cell development through the direct recruitment of PABPs.     

Bioprospecting the African Renaissance: The new value of <Emphasis Type="Italic">muthi</Emphasis> in South Africa

This article gives an overview of anthropological research on bioprospecting in general and of available literature related to bioprospecting particularly in South Africa. It points out how new insights on value regimes concerning plant-based medicines may be gained through further research and is meant to contribute to a critical discussion about the ethics of Access and Benefit Sharing (ABS). In South Africa, traditional healers, plant gatherers, petty traders, researchers and private investors are assembled around the issues of standardization and commercialization of knowledge about plants. This coincides with a nation-building project which promotes the revitalization of local knowledge within the so called African Renaissance. A social science analysis of the transformation of so called Traditional Medicine (TM) may shed light onto this renaissance by tracing social arenas in which different regimes of value are brought into conflict. When medicinal plants turn into assets in a national and global economy, they seem to be manipulated and transformed in relation to their capacity to promote health, their market value, and their potential to construct new ethics of development. In this context, the translation of socially and culturally situated local knowledge about muthi into global pharmaceuticals creates new forms of agency as well as new power differentials between the different actors involved.