Cultured fetal rat pituitaries kept in synthetic medium are able to initiate synthesis of trophic hormones

Summary An immunohistochemical study was performed to determine the capacity of early fetal pituitaries to differentiate into specific hormone-synthesizing tissue in the absence of any influence from the central nervous system. Rathke's pouches from rats were removed from their juxtadiencephalic position on day 11 and 12 of gestation and maintained for 2–7 days in a chemically defined culture medium (M 199) without antibiotics and serum supplementation. The immunocytochemical observations provided evidence for the differentiation of ACTH-, TSH-gb-, LH-gb-, FSH-gb-, GH- and PRL-synthesizing cells in the isolated organ cultured from 11 to 12-day-old pituitary primordia. The appearance of specific hormone-synthesizing cells in vitro displayed a delay of 1.5–2 days compared to the day of appearance in vivo, however, the sequential order of developmental events occurred as observed in vivo. The present results suggest that endocrine or neuroendocrine signals are not required for the expression of specific secretory functions of fetal pituitaries, at least at an age of 11–12 days.     

Environmental,geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species

Aim

The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations.

Location

Global.

Time period

2002–2019.

Major taxa studied

Avian Plasmodium parasites in house sparrows.

Methods

We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests.

Results

Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected.

Main conclusions

Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.     

Analysis of esterase zymograms ofFusarium sambucinum and related species

Esterase zymograms were obtained following polyacrylamide slab gel electrophoresis of protein extractsFusarium sambucinum and related species originating from different geographic locations and different matrices. The sites of esterase activity were recorded, and the R_fs were calculated. The data were used for the construction of phenograms by cluster analysis and nonlinear mapping by computerized classification techniques. The fifteen isolates ofF. sambucinum, the eight isolates ofF. torulosum and the six isolates ofF. spec. nov. each had identical profiles, and are therefore electrophoretically distinct species. The isolates ofF. sarcochroum, one ofF. sambucinum sensu lato (BBA 64280) and fifteen isolates ofF. sambucinum were electrophoretically indistinguishable from each other. We assume they are synonymous. The isolate ofF. bactridioides, one ofF. sambucinum sensu lato (BBA 64993) and eight isolates ofF. torulosum had uniform EST patterns, therefore the two species are electrophoretically identical. We assume they are also synonymous. The remaining three isolates ofF. sambucinum sensu lato are somewhat closely related toF. sambucinum isolates on the basis of our investigations.     

Habitat complexity affects how young of the year Atlantic cod Gadus morhua perceive predation threat from older conspecifics

The response of age 0+ year juvenile Atlantic cod Gadus morhua to the presence of age 1+ and age 3+ year conspecifics was measured with and without cover available. Juveniles reacted by aggregating more closely and maintaining distance from older conspecifics in an experimental setting without cover but only to age 3+ year conspecifics when cover was available. The results indicate that prior residence of older juveniles can affect age 0+ year juveniles during benthic settlement and highlights the conservation value of structurally complex nursery habitats.     

Palaeoecological potential of the marine organic deposits of Posidonia oceanica: A case study in the NE Iberian Peninsula

A high-resolution sedimentary sequence sampled from the Portlligat Bay (NE Iberian Peninsula) has been studied in order to assess its palaeoecological potential. This sedimentary sequence is considered a very particular one, as it is a peat-like deposit derived from the accumulation of the belowground dead parts of the marine phanerogam Posidonia oceanica through the last 1600 years. This study represents the first attempt to explore the palaeoecological potential of such deposits from a palynological point of view, and has allowed the reconstruction of the vegetation dynamics and changes, human impact and the palaeoclimatic characteristics, demonstrating the value of these sedimentary records in palaeopalynological studies.     

A proteomic approach to obesity and type 2 diabetes

The incidence of obesity and type diabetes 2 has increased dramatically resulting in an increased interest in its biomedical relevance. However, the mechanisms that trigger the development of diabetes type 2 in obese patients remain largely unknown. Scientific, clinical and pharmaceutical communities are dedicating vast resources to unravel this issue by applying different omics tools. During the last decade, the advances in proteomic approaches and the Human Proteome Organization have opened and are opening a new door that may be helpful in the identification of patients at risk and to improve current therapies. Here, we briefly review some of the advances in our understanding of type 2 diabetes that have occurred through the application of proteomics. We also review, in detail, the current improvements in proteomic methodologies and new strategies that could be employed to further advance our understanding of this pathology. By applying these new proteomic advances, novel therapeutic and/or diagnostic protein targets will be discovered in the obesity/Type 2 diabetes area.     

Towards a biogeographic regionalization of the European biota

Aim To determine if it is possible to generate analytically derived regionalizations for multiple groups of European plants and animals and to explore potential influences on the regions for each taxonomic group. Location Europe. Methods We subjected range maps of trees, butterflies, reptiles, amphibians, birds and mammals to k‐means clustering followed by v‐fold cross‐validation to determine the pattern and number of regions (clusters). We then used the mean range sizes of species in each group as a correlate of the number of regions obtained for each taxon, and climate and species richness gradients as correlates of the spatial arrangement of the group‐specific regions. We also included the pattern of tree clusters as a predictor of animal clusters in order to test the ‘habitat templet’ concept as an explanation of animal distribution patterns. Results Spatially coherent clusters were found for all groups. The number of regions ranged from three to eight and was strongly associated with the mean range sizes of the species in each taxon. The cluster patterns of all groups were associated with various combinations of climate, underlying species richness gradients and, in the case of animals, the arrangement of tree clusters, although the rankings of the correlates differed among groups. In four of five groups the tree pattern was the strongest single predictor of the animal cluster patterns. Main conclusions Despite a long history of human disturbance and habitat modification, the European biota retains a discernable biogeographic structure. The primary driver appears to be aspects of climate related to water–energy balance, which also influence richness gradients. For many animals, the underlying habitat structure, as measured by tree distributions, appears to have a strong influence on their biogeographic structure, highlighting the need to preserve natural forest formations if we want to preserve the historical signal found in geographic distributions.     

Zonobiomes, zonoecotones and azonal vegetation along the Pacific coast of North America

In this study of the Pacific coast of North America, from Baja California to Alaska, we evaluated the hypothesis that the floristic composition of azonal vegetation determines areas and distribution limits similar to those of the corresponding zonobiomes (ZB), and does so in response to the same macroclimatic changes occurring on the continental scale. To this end, 686 vascular plants of the different habitats found in 279 sites along this coastal strip were recorded. Using an objective classification system (Average Linkage Clustering) and factorial analysis, floristic data acquired in fieldwork were classified into groups, which were in turn related to regional macroclimates. Our main finding was that the azonal coastal vegetation follows a distribution model that is closely linked to the corresponding macroclimate. The four ZB of the northern Pacific coast show a flora and azonal vegetation characteristic to each zonobiome; the latitudinal limits of the azonal vegetation practically coinciding with those already established for the zonal vegetation. The Boreal and Temperate ZB show high percentages of broadly distributed elements. The floristically richest zonobiome in terms of endemic taxa is the Mediterranean zonobiome, whereas the flora of Baja California is characterized by a high number of taxa related to Neotropical flora, especially to those showing links with South America. Data on the geographical distribution and habitats of the 247 most significant coastal species are also provided.     

On the sequential determinants of calpain cleavage

The structural clues of substrate recognition by calpain are incompletely understood. In this study, 106 cleavage sites in substrate proteins compiled from the literature have been analyzed to dissect the signal for calpain cleavage and also to enable the design of an ideal calpain substrate and interfere with calpain action via site-directed mutagenesis. In general, our data underline the importance of the primary structure of the substrate around the scissile bond in the recognition process. Significant amino acid preferences were found to extend over 11 residues around the scissile bond, from P(4) to P(7)'. In compliance with earlier data, preferred residues in the P(2) position are Leu, Thr, and Val, and in P(1) Lys, Tyr, and Arg. In position P(1) ', small hydrophilic residues, Ser and to a lesser extent Thr and Ala, occur most often. Pro dominates the region flanking the P(2)-P(1)' segment, i.e. positions P(3) and P(2)'-P(4)'; most notable is its occurrence 5.59 times above chance in P(3)'. Intriguingly, the segment C-terminal to the cleavage site resembles the consensus inhibitory region of calpastatin, the specific inhibitor of the enzyme. Further, the position of the scissile bond correlates with certain sequential attributes, such as secondary structure and PEST score, which, along with the amino acid preferences, suggests that calpain cleaves within rather disordered segments of proteins. The amino acid preferences were confirmed by site-directed mutagenesis of the autolysis sites of Drosophila calpain B; when amino acids at key positions were changed to less preferred ones, autolytic cleavage shifted to other, adjacent sites. Based on these preferences, a new fluorogenic calpain substrate, DABCYLTPLKSPPPSPR-EDANS, was designed and synthesized. In the case of micro- and m-calpain, this substrate is kinetically superior to commercially available ones, and it can be used for the in vivo assessment of the activity of these ubiquitous mammalian calpains.