Maximising survival by shifting the daily timing of activity

Maximising survival requires animals to balance the competing demands of maintaining energy balance and avoiding predation. Here, quantitative modelling shows that optimising the daily timing of activity and rest based on the encountered environmental conditions enables small mammals to maximise survival. Our model shows that nocturnality is typically beneficial when predation risk is higher during the day than during the night, but this is reversed by the energetic benefit of diurnality when food becomes scarce. Empirical testing under semi‐natural conditions revealed that the daily timing of activity and rest in mice exposed to manipulations in energy availability and perceived predation risk is in line with the model’s predictions. Low food availability and decreased perceived daytime predation risk promote diurnal activity patterns. Overall, our results identify temporal niche switching in small mammals as a strategy to maximise survival in response to environmental changes in food availability and perceived predation risk.     

Specific capture of mammalian cells by cell surface receptor binding to ligand immobilized on gold thin films

Aldehyde-terminated self-assembled monolayers (SAMs) on gold surfaces were modified with proteins and employed to capture intact living cells through specific ligand-cell surface receptor interactions. In our model system, the basic fibroblast growth factor (bFGF) binding receptor was targeted on baby hamster kidney (BHK-21) cells. Negative control and target proteins were immobilized on a gold surface by coupling protein primary amines to surface aldehyde groups. Cell-binding was monitored by phase contrast microscopy or surface plasmon resonance (SPR) imaging. The specificity of the receptor-ligand interaction was confirmed by the lack of cell binding to the negative control proteins, cytochrome c and insulin, and by the disruption of cell binding by treatment with heparitinase to destroy heparan sulfate which plays an essential role in the binding of bFGF to FGF receptors. This approach can simultaneously probe a large number of receptor-ligand interactions in cell populations and has potential for targeting and isolating cells from mixtures according to the receptors expressed on their surface.     

Social and cultural efficacies of medicines: Complications for antiretroviral therapy

Ethnoecological knowledge may be understood as spontaneous knowledge, culturally referenced of any society's members, learned and transmitted through social interactions and that are targeted at resolution of daily routine situations. The traditional knowledge in small scale economy societies as well as the non-academic knowledge in urban-industrial societies might be included in this concept. An ethnoecological approach study was performed here on people living at the communities of Alvinho, Almeida, Chã do Marinho, Floriano, and Chã de Oiti, all located in the municipality of Lagoa Seca, Paraíba state, Northeast Brazil. The general objective pursued here was to study the knowledge that peasant farmers have on management of plant species utilized for pest control. For this, the methodological instruments employed here to investigate the ethnoecological knowledge were: direct observation, structured and semi-structured interviews, and tours conducted by local peasant farmers. We analyzed the data obtained under an emic/etic view and also by comparing the local knowledge with those obtained from the literature. The results showed that people in those communities utilize management alternatives for controlling pests, which are mainly: (i) fallowing; (ii) crop rotation; (iii) destruction of crop remains and fruits attacked by pests; (iv) alternations of crops with repellent plants; and/or (v) mixed cropping; (vi) insect's larvae covered with soil; (vii) crops irrigated abundantly; and (viii) soil preparation. The recovery and comprehension we get about this knowledge as well as the farmers' savoir faire, are extremely important to the revival of ancient agricultural practices, which have been forgotten due to advances in modern agriculture. The data obtained here showed that a huge body of knowledge the farmers have on many forms or strategies of management are generally compatible with scientific knowledge.     

Real-time detection of viable microorganisms by intracellular phototautomerism

Background  

To date, the detection of live microorganisms present in the environment or involved in infections is carried out by enumeration of colony forming units on agar plates, which is time consuming, laborious and limited to readily cultivable microorganisms. Although cultivation-independent methods are available, they involve multiple incubation steps and do mostly not discriminate between dead or live microorganisms. We present a novel generic method that is able to specifically monitor living microorganisms in a real-time manner.     

Genetic mapping of a major gene affecting onion bulb fructan content

The non-structural dry matter content of onion bulbs consists principally of fructose, glucose, sucrose and fructans. The objective of this study was to understand the genetic basis for the wide variation observed in the relative amounts of these carbohydrates. Bulb carbohydrate composition was evaluated in progeny from crosses between high dry matter storage onion varieties and sweet, low dry matter varieties. When samples were analysed on a dry weight basis, reducing sugar and fructan content exhibited high negative correlations and bimodal segregation suggestive of the action of a major gene. A polymorphic SSR marker, ACM235, was identified which exhibited strong disequilibrium with bulb fructan content in F_2:3 families from the ‘W202A’ × ‘Texas Grano 438’ mapping population evaluated in two environments. This marker was mapped to chromosome 8 in the interspecific population ‘Allium cepa × A. roylei’. Mapping in the ‘Colossal Grano PVP’ × ‘Early Longkeeper P12’ F₂ population showed that a dominant major gene conditioning high-fructan content lay in the same genomic region. QTL analysis of total bulb fructan content in the intraspecific mapping population ‘BYG15-23’ × ‘AC43’ using a complete molecular marker map revealed only one significant QTL in the same chromosomal region. This locus, provisionally named Frc, may account for the major phenotypic differences in bulb carbohydrate content between storage and sweet onion varieties.     

The ubiquitin-domain protein HERP forms a complex with components of the endoplasmic reticulum associated degradation pathway

To eliminate misfolded proteins that accumulate in the endoplasmic reticulum (ER) the cell mainly relies on ubiquitin-proteasome dependent ER-associated protein degradation (ERAD). Proteolysis of ERAD substrates by the proteasome requires their ubiquitylation and retro-translocation from the ER to the cytoplasm. Here we describe a high molecular mass protein complex associated with the ER membrane, which facilitates ERAD. It contains the ubiquitin domain protein (UDP) HERP, the ubiquitin protein ligase HRD1, as well as the retro-translocation factors p97, Derlin-1 and VIMP. Our data on the structural arrangement of these ERAD proteins suggest that p97 interacts directly with membrane-resident components of the complex including Derlin-1 and HRD1, while HERP binds directly to HRD1. We propose that ubiquitylation, as well as retro-translocation of proteins from the ER are performed by this modular protein complex, which permits the close coordination of these consecutive steps within ERAD.