Immumoglobulin allotypes in Ecuadorian Cayapa Indians

Indigenous Indian groups comprise approximately 20% of Ecuador's population, the third largest percentage in all of Central or South America, yet immunogenetic data on these groups are lacking in the literature. In the course of population migration studies, sera collected from 65 Ecuadorians living in the northern province of Esmeraldas were typed for six GM and two KM markers. The study population consisted of 47 Cayapa Indians and 18 blacks of African origin, descendants of slaves imported into the area during the seventeenth century. The Cayapa demonstrated three GM phenotypes, two of which are common to other South American Indian tribes. The frequency of KM1 positive Cayapa Indians (63%) is similar to other South American Indian tribes, but is significantly greater than the Huaorani of eastern Ecuador (2%), the only other Ecuadorian Indian group for whom limited immunoglobulin allotype data are available ( ²=35.8, P<0.0001).     

Human hypertensive placenta contains an increased amount of Na,K-ATPase with higher affinity for cardiac glycosides

Placentas of women suffering from pregnancy-induced hypertension (PIH) were found to contain a greater amount of Na,K-ATPase molecules, estimated from anthroyl ouabain binding, than normotensive individuals. Both the microsomal fraction of placental cells and purified Na,K-ATPase showed an increased affinity for the specific inhibitor ouabain which, in the case of the microsomes, bound with a dissociation constant of 0.9 nM as compared with 3.4 nM in the controls. Likewise, the dissociation constant of the ouabain complex with purified Na,K-ATPase was about 3.5 times lower in the hypertensive patients. The differences are apparently caused by a different microenvironment of the ouabain-binding site, as reflected in the quantum yield of bound anthroyl ouabain. If an endogenous digitalis-like factor is present in the body fluids to regulate Na,K-ATPase activity, the present results render its role quite plausible.     

Regulation of Collagen Synthesis in Human Dermal Fibroblasts in Contracted Collagen Gels by Ascorbic Acid, Growth Factors, and Inhibitors of Lipid Peroxidation

Ascorbic acid has been shown to stimulate collagen synthesis in monolayer cultures of human dermal fibroblasts. In the present studies, we examined whether the presence of a collagen matrix influences this response of dermal fibroblasts to ascorbic acid. Fibroblasts and collagen were mixed and allowed to gel and contract for 6 days to form a matrix prior to determining the concentration and time dependence for ascorbic acid to affect collagen synthesis by fibroblasts within the matrix. Collagen synthesis was stimulated at levels at or above 10 μM ascorbic acid and was maximal after 2 days of treatment. This concentration and time dependence is similar to that of cells grown in monolayer cultures. The effects of transforming growth factor-β (TGF-β) and fibroblast growth factor (FGF) were also examined in this model. TGF-β increased and FGF inhibited collagen synthesis in the gels, as has been shown for cells in monolayer cultures. The effects of potential inhibitors of lipid peroxidation induced by ascorbic acid were also examined in these matrices and compared to previous results obtained in monolayer cultures. Propyl gallate, cobalt chloride, α,α-dipyridyl, and α-tocopherol inhibited the ascorbic acid-mediated stimulation of collagen synthesis while mannitol had no effect. Natural retinoids inhibited total protein synthesis without the specific effect on collagen synthesis that was seen in monolayer cultures. These results indicate that ascorbic acid stimulates collagen synthesis in fibroblasts grown in a collagen matrix in a manner similar to that found in monolayer cultures. In contracting collagen gels, however, the magnitude of the effect is less and retinoids do not specifically inhibit collagen synthesis.     

Analysis of parameters about useful life extension in 70 tools and methods related to eco-design and circular economy

One of the approaches followed by the circular economy (CE) to achieve sustainability through design is product life extension. Extending the life of products to make them useful for as long as possible is a means to reduce waste production and materials consumption, as well as the related impacts. For designers, conceptualizing products in a way that allows them to be used for longer is a challenge, and assessing how well they extend their lifespan can be helpful when it comes to choosing the best proposal. In this paper, 70 tools and methods related to eco-design and circular economy are studied to determine how many of them consider parameters related to life extension and which can be applied in the early stages of design. The results of the analysis show that most of the existing tools and methods are applicable to developed products, and only a few of them take into account parameters related to extending the useful life. Of the 70 tools and methods, only 14 include some parameter related to life extension and are applicable to concepts. CE toolkit, Eco-design PILOT, CE Designer, Circularity Assessment tool, Circularity Potential Indicator and Circular Design Tools take into consideration eight or more parameters to assess life extension in concepts. This will help designers select the most appropriate and will indicate the need for more complete tools to consider useful life extension in the early stages of design and thus enhance the selection of more sustainable products.     

Proportional processing of a visual mate choice signal in the green swordtail,Xiphophorus hellerii

During mate choice, receivers often assess the magnitude (duration, size, etc.) of signals that vary along a continuum and reflect variation in signaller quality. It is generally assumed that receivers assess this variation linearly, meaning each difference in signalling trait between signallers results in a commensurate change in receiver response. However, increasing evidence shows receivers can respond to signals non-linearly, for example through Weber's Law of proportional processing, where discrimination between stimuli is based on proportional, rather than absolute, differences in magnitude. We quantified mate preferences of female green swordtail fish, Xiphophorus hellerii, for pairs of males differing in body size. Preferences for larger males were better predicted by the proportional difference between males (proportional processing) than the absolute difference (linear processing). This demonstration of proportional processing of a visual signal implies that receiver perception may be an important mechanism selecting against the evolution of ever-larger signalling traits.     

Effects of media composition on substrate removal by pure and mixed bacterial cultures

Continuous culture experiments with identical experimental designs were run with a mixed microbial community of activated sludge origin and an axenic bacterial culture derived from it. Each culture received 2-chlorophenol (2-CP) at a concentration of 160 mg/L as COD and L-lysine at a concentration of 65 mg/L as COD. A factorial experimental design was employed with dilution rate and media composition as the two controlled variables. Three dilution rates were studied: 0.015, 0.0325, and 0.05 h^–1. Media composition was changed by adding four biogenic compounds (butyric acid, thymine, glutamic acid and lactose) in equal COD proportions at total concentrations of 0, 34, 225, and 1462 mg/L as COD. The measured variables were the effluent concentrations of 2-CP as measured by the 4-aminoantipyrene test and lysine as measured by the o-diacetylbenzene procedure. The results suggest that community structure and substrate composition play important roles in the response of a microbial community to mixed substrates. The addition of more biogenic substrates to the axenic culture had a deleterious effect on the removal of both lysine and 2-CP, although the effect was much larger on lysine removal. In contrast, additional substrates had a positive effect on the removal of 2-CP by the mixed community and much less of a negative effect on the removal of lysine. The dilution rate at which the cultures were growing had relatively little impact on the responses to the additional substrates.Abbreviations COD chemical oxygen demand - 2-CP 2-chlorophenol - DOC dissolved organic carbon - MDL method detection limit - SS suspended solids