Irregular distribution of mammary-derived growth inhibitor in the bovine mammary epithelium

Localization of a mammary-derived growth inhibitor (MDGI) in the bovine mammary gland was verified by light-and electron-microscopic methods. Expression of MDGI, which is known to inhibit the growth of mammary epithelial cell lines in vitro, was found to be highest in the late pregnant and in the lactating state. A combination of immunohistochemical and immunocytochemical methods with semi- and ultrathin resin sections revealed marked variations in MDGI staining. High MDGI levels were predominantly detectable in epithelial cells with large milk fat droplets. Distinct cell types that were almost free of label could be identified among bovine mammary epithelial cells that always exhibited high MDGI levels. Similar results were obtained when using a serum-free organ culture system in which MDGI was hormonally induced in cell types of comparable differentiation state. The specific occurrence of the growth inhibitor in developing alveoli and certain cell types points to the association between MDGI expression and functional differentiation in the normal mammary gland.     

Gel retardation analysis of E. coli M1 RNA-tRNA complexes.

We have analyzed complexes between tRNA and E. coli M1 RNA by electrophoresis in non-denaturing polyacrylamide gels. The RNA subunit of E. coli RNase P formed a specific complex with mature tRNA molecules. A derivative of the tRNA(Gly), endowed with the intron of yeast tRNA(ile) (60 nt), was employed to improve separation of complexed and unbound M1 RNA. Binding assays with tRNA(Gly) and intron-tRNA(Gly) as well as analysis of intron-tRNA/M1 RNA complexes on denaturing gels showed that one tRNA is bound per molecule of M1 RNA. A tRNA carrying a truncation as small as the 5'-nucleotide had a strongly reduced affinity to M1 RNA and was also a weak competitor in the cleavage reaction, suggesting that nucleotide +1 is a major determinant of tRNA recognition and that the thermodynamically stable tRNA-M1 RNA complex is relevant for enzyme function. Binding was shown to be dependent on the M1 RNA concentration in a cooperative fashion. Only a fraction of M1 RNAs (50-60%) readily formed a complex with intron-tRNA(Gly), indicating that distinct conformational subpopulations of M1 RNA may exist. Formation of the M1 RNA-tRNA(Gly), complex was very similar at 100 mM Mg++ and Ca++, corroborating earlier data that Ca++ is competent in promoting M1 RNA folding and tRNA binding. Determination of apparent equilibrium constants (app Kd) for tRNA(Gly) as a function of the Mg++ concentration supports an uptake of at least two additional Mg++ ions upon complex formation. At 20-30 mM Mg++, highest cleavage rates but strongly reduced complex formation were observed. This indicates that tight binding of the tRNA to the catalytic RNA at higher magnesium concentrations retards product release and therefore substrate turnover.     

Casearia Essential Oil: An Updated Review on the Chemistry and Pharmacological Activities

Casearia species are found in the America, Africa, Asia, and Australia and present pharmacological activities, besides their traditional uses. Here, we reviewed the chemical composition, content, pharmacological activities, and toxicity of the essential oils (EOs) from Casearia species. The EO physical parameters and leaf botanical characteristics were also described. The bioactivities of the EOs from the leaves and their components include cytotoxicity, anti-inflammatory, antiulcer, antimicrobial, antidiabetic, antioxidant, antifungal, and antiviral activities. The main components associated with these activities are the α-zingiberene, (E)-caryophyllene, germacrene D, bicyclogermacrene, spathulenol, α-humulene, β-acoradiene, and δ-cadinene. Data on the toxicity of these EOs are scarce in the literature. Casearia sylvestris Sw. is the most studied species, presenting more significant pharmacological potential. The chemical variability of EOs components was also investigated for this species. Caseria EOs have relevant pharmacological potential and must be further investigated and exploited.     

BLOEM: A spatially explicit model of bioenergy and carbon capture and storage,applied to Brazil

Bioenergy could play a major role in decarbonizing energy systems in the context of the Paris Agreement. Large-scale bioenergy deployment could be related to sustainability issues and requires major infrastructure investments. It, therefore, needs to be studied carefully. The Bioenergy and Land Optimization Spatially Explicit Model (BLOEM) presented here allows for assessing different bioenergy pathways while encompassing various dimensions that influence their optimal deployment. In this study, BLOEM was applied to the Brazilian context by coupling it with the Brazilian Land Use and Energy Systems (BLUES) model. This allowed investigating the most cost-effective ways of attending future bioenergy supply projections and studying the role of recovered degraded pasture lands in improving land availability in a sustainable and competitive manner. The results show optimizing for limiting deforestation and minimizing logistics costs results in different outcomes. It also indicates that recovering degraded pasture lands is attractive from both logistics and climate perspectives. The systemic approach of BLOEM provides spatial results, highlighting the trade-offs between crop allocation, land use and the logistics dynamics between production, conversion, and demand, providing valuable insights for regional and national climate policy design. This makes it a useful tool for mapping sustainable bioenergy value chain pathways.     

Geographic variation in sexual dimorphism in the barn owl Tyto alba: a role for direct selection or genetic correlation?

Geographic variation in sexually selected traits is commonly attributed to geographic variation in the net benefit accrued from bearing such traits. Although natural and sexual selection are potentially important in shaping geographic variation, genetic constraints may also play a role. Although a genetic correlation between two traits may itself be the outcome of natural or sexual selection, it may indirectly reinforce the establishment and maintenance of cline variation with respect to one particular trait when across the cline different values of other traits are selected. Using the barn owl Tyto alba, a species in which the plumage of females is more reddish‐brown and more marked with black spots than that of males, I report results that are consistent with the hypothesis that both direct selection and genetic constraints may help establish and maintain cline variation in sexual dichromatism. In this species, inter‐individual variation in plumage coloration and spottiness has a genetic basis, and these traits are not sensitive to the environment. Data, based on the measurement of skin specimens, is consistent with the hypothesis that the stronger European cline variation in male spottiness than in female spottiness depends on the combined effects of (1) the similar cline variation in male and female plumage coloration and (2) the more intense phenotypic correlation between plumage coloration and spottiness in males (darker birds are more heavily spotted in the two sexes, but especially males) which is a general feature among the globally distributed barn owls. In northern Europe, male and female T. a. guttata are reddish‐brown and heavily spotted, and in southern Europe male and female T. a. alba are white, but only females display many spots. Here, I discuss the relative importance of direct selection, genetic correlation and the post‐ice age invasion of Europe by T. alba, in generating sex‐specific cline variation in plumage spottiness and non‐sex‐specific cline variation in plumage coloration.     

Do NOE distances contain enough information to assess the relative populations of multi-conformer structures?

Summary The feasibility of determining the relative populations of multi-conformer structures from NOE-derived distances alone is assessed. Without cross-validation of the NOE restraints, any population ratio can be refined to a similar quality of the fit. Complete cross-validation provides a less biased measure of fit and allows the estimation of the correct population ratio when used in conjunction with very tight distance restraints. With the qualitative distance restraints most commonly used in NMR structure determination, cross-validation is unsuccessful in providing the correct answer. Other experimental sources are therefore needed to determine relative populations of multi-conformer structures.To whom correspondence should be addressed.