A state and transition model for the eastern Monte Phytogeographycal Province in Rio Negro

We developed a functional model for a shrub steppe vegetation of the eastern Monte Phytogeographical Province in Río Negro (Argentina) with six stable states and 12 transitions, based on the woody encroachment degree, characteristics of the herbaceous layer and the soil surface, and biological crust cover. Information was obtained from letters of naturalists and travelers along the region since the late eighteenth century, reports of old settlers, and our own research work. On the Monte, different functional groups can be distinguished. Our work focused on the three most conspicuous to analyze the dynamics of the system: shrubs, grasses and biological crust. The shrub layer is only affected by large-scale disturbances (fire, mechanical clearing) which maintain the balance between grasses and shrubs in the system. Mechanical clearing with soil removal also causes a decrease in grass cover and vegetation diversity. This layer, however, is most frequently affected by intensive and continuous grazing, which reduces the occurrence of fires and shifts the equilibrium toward the shrubs. All disturbances in general deteriorate the biological crust that covers the soil, which offers situations of facilitation for the regeneration of the herbaceous layer. Grazing and mechanical clearing reduce soil cover and promote the development of soil compaction, which reduce water infiltration and germination and/or seedling establishment, and this creates deteriorated states difficult to reverse. Those states can also be produced by tillage for agriculture and stubble grazing. Some of the transitions that we describe can be favored through grassland management strategies, in order to reach higher states of pastoral value and reverse deteriorating situations.     

Purification of galectin-3 from ovine placenta: developmentally regulated expression and immunological relevance

Galectins, beta-galactoside-binding lectins, are extensively distributed in the animal kingdom and share some basic molecular properties. Galectin-3, a member of this family, is generally associated with differentiation, morphogenesis, and metastasis. In this study, galectin-3 was isolated from ovine placental cotyledons round the middle of the gestation period by lactose extraction followed by affinity chromatography on lactosyl-agarose, and separated from galectin-1 by size exclusion chromatography on a Superose 12 column. Under native conditions this lectin behaved as a monomer with an apparent molecular weight of approximately 29,000 and an isoelectric point of 9.0. The partial amino acid sequence of the peptides obtained by tryptic digestion of this protein followed by HPLC separation showed striking homology with other members of the galectin-3 subfamily. Furthermore, ovine placental galectin-3 exhibited specific mitogenic activity toward rat spleen mononuclear cells. Besides, this protein strongly reacted with a rabbit antiserum raised against a chicken galectin. Results obtained by Western blot analysis showed that its expression was greatly decreased in term placenta with respect to the middle of the gestation period, suggesting a regulated expression throughout development.      

Taxol from fungal endophytes and the issue of biodiversity

Fungi represent one of the most understudied and diverse group of organisms. Commonly, these organisms make associations with higher life forms and may proceed to biochemically mimic the host organism. An excellent example of this is the anticancer drug, taxol, which had been previously supposed to occur only in the plant genusTaxus (yew). However, taxol has been reported in a novel endophytic fungus—Taxomyces andreanae, but also has been demonstrated to occur in a number of unrelated fungal endophytes includingPestalotia, Pestalotiopsis, Fusarium, Alternaria, Pithomyces, Monochaetia and others. Thus, this report presents information on the presence of taxol among disparate fungal genera, and uses these observations as an additional argument to support efforts to study fungal endophytes and preserve their associated host plants.     

IGF-1 modulates gene expression of proteins involved in inflammation,cytoskeleton, and liver architecture

Even though the liver synthesizes most of circulating IGF-1, it lacks its receptor under physiological conditions. However, according to previous studies, a damaged liver expresses the receptor. For this reason, herein, we examine hepatic histology and expression of genes encoding proteins of the cytoskeleton, extracellular matrix, and cell-cell molecules and inflammation-related proteins. A partial IGF-1 deficiency murine model was used to investigate IGF-1’s effects on liver by comparing wild-type controls, heterozygous igf1^+/?, and heterozygous mice treated with IGF-1 for 10 days. Histology, microarray for mRNA gene expression, RT-qPCR, and lipid peroxidation were assessed. Microarray analyses revealed significant underexpression of igf1 in heterozygous mice compared to control mice, restoring normal liver expression after treatment, which then normalized its circulating levels. IGF-1 receptor mRNA was overexpressed in Hz mice liver, while treated mice displayed a similar expression to that of the controls. Heterozygous mice showed overexpression of several genes encoding proteins related to inflammatory and acute-phase proteins and underexpression or overexpression of genes which coded for extracellular matrix, cytoskeleton, and cell junction components. Histology revealed an altered hepatic architecture. In addition, liver oxidative damage was found increased in the heterozygous group. The mere IGF-1 partial deficiency is associated with relevant alterations of the hepatic architecture and expression of genes involved in cytoskeleton, hepatocyte polarity, cell junctions, and extracellular matrix proteins. Moreover, it induces hepatic expression of the IGF-1 receptor and elevated acute-phase and inflammation mediators, which all resulted in liver oxidative damage.     

Accounting for multiple ecosystem services in a simulation of land‐use decisions: Does it reduce tropical deforestation?

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio‐economic objectives in decision‐making. To test the effect of accounting for both ES and socio‐economic objectives in land‐use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests. We integrate multi‐objective optimization of land allocation with an innovative approach to consider uncertainty spaces for each objective. These uncertainty spaces account for potential variability among decision‐makers, who may have different expectations about the future. When optimizing only socio‐economic objectives, the model continues the past trend in deforestation (1975–2015) in the projected land‐use allocation (2015–2070). Based on indicators for biomass production, carbon storage, climate and water regulation, and soil quality, we show that considering multiple ES in addition to the socio‐economic objectives has heterogeneous effects on land‐use allocation. It saves some natural forest if the natural forest share is below 38%, and can stop deforestation once the natural forest share drops below 10%. For landscapes with high shares of forest (38%–80% in our study), accounting for multiple ES under high uncertainty of their indicators may, however, accelerate deforestation. For such multifunctional landscapes, two main effects prevail: (a) accelerated expansion of diversified non‐natural areas to elevate the levels of the indicators and (b) increased landscape diversification to maintain multiple ES, reducing the proportion of natural forest. Only when accounting for vascular plant species richness as an explicit objective in the optimization, deforestation was consistently reduced. Aiming for multifunctional landscapes may therefore conflict with the aim of reducing deforestation, which we can quantify here for the first time. Our findings are relevant for identifying types of landscapes where this conflict may arise and to better align respective policies.     

Correction to: A New Species of Ctenomys (Rodentia: Ctenomyidae) from Patagonia Related to C. sociabilis

Journal of Mammalian Evolution -     

Thermodynamic and Kinetic Characterization of a Germ Line Human λ6 Light-Chain Protein: The Relation between Unfolding and Fibrillogenesis

Proteins encoded by the gene segment 6a of the λ variable light-chain repertoire are strongly associated with amyloid deposition. 6aJL2 is a model protein constructed with the predicted sequences encoded by the 6a and JL2 germ line genes. In this work, we characterized the urea- and temperature-induced unfolding of 6aJL2. In the short time scale, spectroscopic, hydrodynamic and calorimetric experiments were compatible with a two-state transition. Furthermore, ΔG, m and the midpoint urea concentration obtained from equilibrium experiments were compatible with those obtained from kinetic experiments. Since fibril formation is a slow process, samples were also incubated for longer times. After incubation for several hours at 37 °C, spectroscopic, hydrodynamic and calorimetric experiments revealed the presence of a partially unfolded off-pathway intermediate around the midpoint urea concentration (1.5-3.0 M urea). In vitro fibrillogenesis assays show that the maximum growth rate for fibril formation and the minimum lag time were obtained at urea concentrations where the partially unfolded state was populated (2.5 M urea at 37 °C). This indicates that this partially unfolded state is critical for in vitro fibril formation. Concentration-dependent kinetics and hydrodynamic properties of the intermediate were consistent with a soluble oligomeric state. The intermediate is formed around the midpoint urea concentration, where the native and unfolded states are equally populated and their rate of interconversion is the slowest. This situation may promote the slow accumulation of an intermediate state that is prone to aggregate.     

Total fertilization failure and idiopathic subfertility

Background  

To gain more insight in whether failure of intrauterine insemination (IUI) treatment in patients with idiopathic subfertility could be related to diminished fertilization, the aim of this study is to compare the fertilization of an initial IVF procedure after six cycles of IUI and the fertilization of an initial IVF procedure without preceding IUI cycles in couples with idiopathic subfertility.