Biogeographical analysis of two Polypodium species complexes (Polypodiaceae) in Mexico and Central America

We analyzed the geographical and elevational distributions of two Polypodium complexes from Mexico and Central America. Distribution data of nine species of the Polypodium colpodes complex and the Polypodium plesiosorum complex were obtained from almost 1500 herbarium specimens, field collections in Mexico and Costa Rica, and literature studies. The presence of each species was recorded for each Mesoamerican country, in 1° × 1° grid‐cells and biogeographical provinces. The rarity of species was also evaluated. Although the two complexes show extensive overlap, the P. colpodes complex is distributed mainly along the Pacific versant of Mexico and Central America, whereas the P. plesiosorum complex occurs mainly along the Atlantic versant. Those biogeographical provinces with maximum species diversity are Chiapas (seven species), Sierra Madre del Sur (six species), and the Trans‐Mexican Volcanic belt (six species). Grid‐cells with more species are located mainly in the mountains of central‐southern Mexico and northern Central America. Richness does not decrease or increase with latitude. Elevation distributions showed that most Polypodium species are concentrated in the montane interval and three species groups were recognized based on elevational preferences. Polypodium colpodes and P. plesiosorum are the most widely distributed species, whereas Polypodium castaneum and Polypodium flagellare are the only two species that possess the three attributes of rarity (narrow geographical distribution, high habitat specificity, and scarce local populations). Polypodium species of both complexes are present mainly in the montane regions of the study area and show some degree of geographical sympatry, especially in southern Mexico and northern Central America. This overlapping is explained by the elevation tolerance within montane systems and because most species inhabit three or more vegetation types. The distributional patterns of these complexes coincided with the three regional highlands of Mesoamerica, which are separated from each other by the Isthmus of Tehuantepec and by the lowlands of Nicaragua. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Expression of multiple proliferin genes in mouse cells.

Several copies of the prolactin-related proliferin gene were detected in the mouse genome, encoding at least two distinct forms of proliferin. These forms correspond to proliferin cDNA clones derived from BALB/c 3T3 tissue culture and BALB/c placental RNA. Tissue culture and placental cells were each found to express both forms of proliferin.     

Aggregation risk prediction for antibodies and its application to biotherapeutic development

Aggregation is a common problem affecting biopharmaceutical development that can have a significant effect on the quality of the product, as well as the safety to patients, particularly because of the increased risk of immune reactions. Here, we describe a new high-throughput screening algorithm developed to classify antibody molecules based on their propensity to aggregate. The tool, constructed and validated on experimental aggregation data for over 500 antibodies, is able to discern molecules with a high aggregation propensity as defined by experimental criteria relevant to bioprocessing and manufacturing of these molecules. Furthermore, we show how this tool can be combined with other computational approaches during early drug development to select molecules with reduced risk of aggregation and optimal developability properties.     

Protein phosphatase 2A regulatory subunits affecting plant innate immunity,energy metabolism,and flowering time – joint functions among B'η subfamily members

Protein phosphatase 2A (PP2A) is a heterotrimeric complex comprising a catalytic, scaffolding, and regulatory subunit. The regulatory subunits are essential for substrate specificity and localization of the complex and are classified into B/B55, B'', and B” non-related families in higher plants. In Arabidopsis thaliana, the close paralogs B''η, B''θ, B''γ, and B''ζ were further classified into a subfamily of B'' called B''η. Here we present results that consolidate the evidence for a role of the B''η subfamily in regulation of innate immunity, energy metabolism and flowering time. Proliferation of the virulent Pseudomonas syringae in B''θ knockout mutant decreased in comparison with wild type plants. Additionally, B''θ knockout plants were delayed in flowering, and this phenotype was supported by high expression of FLC (FLOWERING LOCUS C). B''ζ knockout seedlings showed growth retardation on sucrose-free medium, indicating a role for B''ζ in energy metabolism. This work provides insight into functions of the B''η subfamily members, highlighting their regulation of shared physiological traits while localizing to distinct cellular compartments.     

A systematic comparative and structural analysis of protein phosphorylation sites based on the mtcPTM database

mtcPTM is an online repository of human and mouse phosphosites in which data are hierarchically organized to preserve biologically relevant experimental information, thus allowing straightforward comparisons of phosphorylation patterns found under different conditions. The database also contains the largest available collection of atomic models of phosphorylatable proteins. Detailed analysis of this structural dataset reveals that phosphorylation sites are found in a heterogeneous range of structural and sequence contexts. mtcPTM is available on the web .     

Induction of megakaryocyte differentiation by a novel pregnancy-specific hormone.

Maturation of megakaryocytes and subsequent platelet release are normally regulated by a network of cytokines, including thrombopoietin and various interleukins. Because abnormal platelet production and activation have been implicated in gestational pathologies, additional pregnancy-specific cytokines may play important roles in the regulation of megakaryocytopoiesis. Consistent with this hypothesis, we have found that the hormone prolactin-like protein E, a placental hormone that we have recently characterized, targets megakaryocytes through a specific cell surface receptor and induces megakaryocyte differentiation through a gp130-dependent signal transduction pathway.     

Inhibition of tumor growth by the antiangiogenic placental hormone, proliferin-related protein

Proliferin-related protein (PRP) is a potent placental antiangiogenic hormone. To test the antiangiogenic potential of PRP to block tumor growth, we engineered tumor cells to express this hormone. Both SV40-transformed BALB/c mouse 3T3 fibroblasts and rat C6 glioma cells have markedly reduced growth rates as tumors in mice if they express high levels of PRP. In both models, the small tumors that form are largely avascular, whereas control tumors are rich in blood vessels, consistent with PRP limiting tumor growth by preventing neovascularization of the tumors. The antiangiogenic effects of PRP are also detected on human endothelial cells, suggesting that the receptor and signaling pathway of this mouse hormone are conserved between mouse and human and may represent useful targets for the development of antiangiogenic therapeutics. That signaling pathway appears to involve an inhibition of arachidonic acid release, based on the ability of arachidonic acid to overcome the antiangiogenic effects of PRP.     

Reproductive behaviour and vibratory communication of the neotropical predatory stink bug Podisus nigrispinus

Vibratory communication during reproductive behaviour is less well described in predatory (Asopinae) than in phytophagous (Pentatominae) stink bugs. Different steps in the mating behaviour of the predatory stink bug Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae; Asopinae) are described in the present study, together with vibratory signals emitted on artificial and natural substrate during courtship and copulation. Vibratory signals in Podisus nigrispinus have a decisive role in copulation success and are produced in both sexes by abdominal vibration and tremulation. In P. nigrispinus, one species‐specific female and two male songs, which do not show the calling function typically found in phytophagous stink bugs, are produced by abdominal vibration and are emitted during reproductive behaviour. Additionally, P. nigrispinus produces tremulatory signals that have no species or sex specificity. Tremulatory signals emitted spontaneously on a plant as a sequence of readily repeated pulses are similar to the calling songs of the Pentatominae stink bug. These signals may carry information on the presence of a mate; however, in other behavioural contexts, they may have a different function, such as advertisement or even alarm signals. Plants transmit vibratory signals produced by both mechanisms as a low‐pass filter, increasing the amount of low‐frequency components. The results of the present study raise important questions about the interaction between chemical and vibratory signals in the mating behaviour of predatory stink bugs.