The C-terminal cysteine annulus participates in auto-chaperone function for Salmonella phage P22 tailspike folding and assembly

Elongated trimeric adhesins are a distinct class of proteins employed by phages and viruses to recognize and bind to their host cells, and by bacteria to bind to their target cells and tissues. The tailspikes of E. coli phage K1F and Bacillus phage Ø29 exhibit auto-chaperone activity in their trimeric C-terminal domains. The P22 tailspike is structurally homologous to those adhesins. Though there are no disulfide bonds or reactive cysteines in the native P22 tailspikes, a set of C-terminal cysteines are very reactive in partially folded intermediates, implying an unusual local conformation in the domain. This is likely to be involved in the auto-chaperone function. We examined the unusual reactivity of C-terminal tailspike cysteines during folding and assembly as a potential reporter of auto-chaperone function. Reaction with IAA blocked productive refolding in vitro, but not off-pathway aggregation. Two-dimensional PAGE revealed that the predominant intermediate exhibiting reactive cysteine side chains was a partially folded monomer. Treatment with reducing reagent promoted native trimer formation from these species, consistent with transient disulfide bonds in the auto-chaperone domain. Limited enzymatic digestion and mass spectrometry of folding and assembly intermediates indicated that the C-terminal domain was compact in the protrimer species. These results indicate that the C-terminal domain of the P22 tailspike folds itself and associates prior to formation of the protrimer intermediate, and not after, as previously proposed. The C-terminal cysteines and triple β-helix domains apparently provide the staging for the correct auto-chaperone domain formation, needed for alignment of P22 tailspike native trimer

Bacterial cellulose production by Gluconacetobacter xylinus by employing alternative culture media

Bacterial cellulose (BC) is used in different fields as a biological material due to its unique properties. Despite there being many BC applications, there still remain many problems associated with bioprocess technology, such as increasing productivity and decreasing production cost. New technologies that use waste from the food industry as raw materials for culture media promote economic advantages because they reduce environmental pollution and stimulate new research for science sustainability. For this reason, BC production requires optimized conditions to increase its application. The main objective of this study was to evaluate BC production by Gluconacetobacter xylinus using industry waste, namely, rotten fruits and milk whey, as culture media. Furthermore, the structure of BC produced at different conditions was also determined. The culture media employed in this study were composed of rotten fruit collected from the disposal of free markets, milk whey from a local industrial disposal, and their combination, and Hestrin and Schramm media was used as standard culture media. Although all culture media studied produced BC, the highest BC yield60 mg/mLwas achieved with the rotten fruit culture. Thus, the results showed that rotten fruit can be used for BC production. This culture media can be considered as a profitable alternative to generate high-value products. In addition, it combines environmental concern with sustainable processes that can promote also the reduction of production cost.The authors would like to acknowledge the Brazil National Council of Technological and Scientific Development (CNPq, FAPESP, and CAPES), the financial support from FAPESP 2009/14897-7, and Fundacao para a Ciencia e a Tecnologia (FCT)/Portugal through the project PTDC/EBB-EBI/112170/2009 for the financial support and scholarship. Special thanks to Talita Almeida Vicentin for technical support

The Perceived Benefits of Height: Strength, Dominance, Social Concern, and Knowledge among Bolivian Native Amazonians

Research in industrial countries suggests that, with no other knowledge about a person, positive traits are attributed to taller people and correspondingly, that taller people have slightly better socioeconomic status (SES). However, research in some non-industrialized contexts has shown no correlation or even negative correlations between height and socioeconomic outcomes. It remains unclear whether positive traits remain attributed to taller people in such contexts. To address this question, here we report the results of a study in a foraging-farming society of native Amazonians in Bolivia (Tsimane’)–a group in which we have previously shown little association between height and socioeconomic outcomes. We showed 24 photographs of pairs of Tsimane’ women, men, boys, and girls to 40 women and 40 men >16 years of age. We presented four behavioral scenarios to each participant and asked them to point to the person in the photograph with greater strength, dominance, social concern, or knowledge. The pairs in the photographs were of the same sex and age, but one person was shorter. Tsimane’ women and men attributed greater strength, dominance, and knowledge to taller girls and boys, but they did not attribute most positive traits to taller adults, except for strength, and more social concern only when women assessed other women in the photographs. These results raise a puzzle: why would Tsimane’ attribute positive traits to tall children, but not tall adults? We propose three potential explanations: adults’ expectations about the more market integrated society in which their children will grow up, height as a signal of good child health, and children’s greater variation in the traits assessed corresponding to maturational stages

Subtype-associated differences in HIV-1 reverse transcription affect the viral replication

Background: The impact of the products of the pol gene, specifically, reverse transcriptase (RT) on HIV-1 replication, evolution, and acquisition of drug resistance has been thoroughly characterized for subtype B. For subtype C, which accounts of almost 60% of HIV cases worldwide, much less is known. It has been reported that subtype C HIV-1 isolates have a lower replication capacity than B; however, the basis of these differences remains unclear. Results: We analyzed the impact of the pol gene products from HIV-1 B and C subtypes on the maturation of HIV virions, accumulation of reverse transcription products, integration of viral DNA, frequency of point mutations in provirus and overall viral replication. Recombinant HIV-1 viruses of B and C subtypes comprising the pol fragments encoding protease, integrase and either the whole RT or a chimeric RT from different isolates of the C and B subtypes, were used for infection of cells expressing CXCR4 or CCR5 co-receptors. The viruses carrying different fragments of pol from the isolates of B and C subtypes did not reveal differences in Gag and GagPol processing and viral RNA incorporation into the virions. However, the presence of the whole RT from subtype C, or the chimeric RT containing either the polymerase or the connection and RNase H domains from C isolates, caused significantly slower viral replication regardless of B or C viral backbone. Subtype C RT carrying viruses displayed lower levels of accumulation of strong-stop cDNA in permeabilized virions during endogenous reverse transcription, and decreased accumulation of both strong-stop and positive strand reverse transcription products in infected cells and in isolated reverse transcription complexes. This decreased accumulation correlated with lower levels of viral DNA integration in cells infected with viruses carrying the whole RT or RT domains from subtype C isolates. The single viral genome assay analysis did not reveal significant differences in the frequency of point mutations between the RT from B or C subtypes. Conclusions: These data suggest that the whole RT as well as distinct polymerase and connection-RNase H domains from subtype C HIV-1 confer a lower level of accumulation of reverse transcripts in the virions and reverse transcription complexes as compared to subtype B, resulting in a lower overall level of virus replication

Trust in telemedicine portals for rehabilitation care: an exploratory focus group study with patients and healthcare professionals

Background: For many eServices, end-user trust is a crucial prerequisite for use. Within the context of Telemedicine, the role of trust has hardly ever been studied. In this study, we explored what determines trust in portals that facilitate rehabilitation therapy, both from the perspective of the patient and the healthcare professional. Methods: We held two focus groups with patients (total n = 15) and two with healthcare professionals (total n = 13) in which we discussed when trust matters, what makes up trust in a rehabilitation portal, what effect specific design cues have, and how much the participants trust the use of activity sensor data for informing treatment. Results: Trust in a rehabilitation portal is the sum of trust in different factors. These factors and what makes up these factors differ for patients and healthcare professionals. For example, trust in technology is made up, for patients, mostly by a perceived level of control and privacy, while for healthcare professionals, a larger and different set of issues play a role, including technical reliability and a transparent data storage policy. Healthcare professionals distrust activity sensor data for informing patient treatment, as they think that sensors are unable to record the whole range of movements that patients make (e.g., walking and ironing clothes). Conclusions: The set of factors that affect trust in a rehabilitation portal are different from the sets that have been found for other contexts, like eCommerce. Trust in telemedicine technology should be studied as a separate subject to inform the design of reliable interventions