Sustainable ecotourism in Costa Rica: the Monteverde Cloud Forest Preserve

The paper discusses the sustainability of the Monteverde Cloud Forest Preserve in the context of Costa Rican ecotourism. While the history of the Preserve is somewhat unique, the analysis of visitation, financial, ecological and economic factors provides a convincing case that tourism at the Preserve is sustainable. The experience of the Preserve is also put in the context of Costa Rican ecotourism, particularly to the national parks. The paper concludes that the Preserve has played a very important role in the development of Costa Rica as an ecotourism destination. Nonetheless, the failure of experience at the Preserve to inform recent changes in national park pricing policy reveal that Costa Rica has yet to fully capitalize on the experience gained and lessons learned at the Preserve.     

Comparison of 26 Sphingomonad Genomes Reveals Diverse Environmental Adaptations and Biodegradative Capabilities

Sphingomonads comprise a physiologically versatile group within the Alphaproteobacteria that includes strains of interest for biotechnology, human health, and environmental nutrient cycling. In this study, we compared 26 sphingomonad genome sequences to gain insight into their ecology, metabolic versatility, and environmental adaptations. Our multilocus phylogenetic and average amino acid identity (AAI) analyses confirm that Sphingomonas, Sphingobium, Sphingopyxis, and Novosphingobium are well-resolved monophyletic groups with the exception of Sphingomonas sp. strain SKA58, which we propose belongs to the genus Sphingobium. Our pan-genomic analysis of sphingomonads reveals numerous species-specific open reading frames (ORFs) but few signatures of genus-specific cores. The organization and coding potential of the sphingomonad genomes appear to be highly variable, and plasmid-mediated gene transfer and chromosome-plasmid recombination, together with prophage- and transposon-mediated rearrangements, appear to play prominent roles in the genome evolution of this group. We find that many of the sphingomonad genomes encode numerous oxygenases and glycoside hydrolases, which are likely responsible for their ability to degrade various recalcitrant aromatic compounds and polysaccharides, respectively. Many of these enzymes are encoded on megaplasmids, suggesting that they may be readily transferred between species. We also identified enzymes putatively used for the catabolism of sulfonate and nitroaromatic compounds in many of the genomes, suggesting that plant-based compounds or chemical contaminants may be sources of nitrogen and sulfur. Many of these sphingomonads appear to be adapted to oligotrophic environments, but several contain genomic features indicative of host associations. Our work provides a basis for understanding the ecological strategies employed by sphingomonads and their role in environmental nutrient cycling.     

The Genome Sequences of Cellulomonas fimi and “Cellvibrio gilvus” Reveal the Cellulolytic Strategies of Two Facultative Anaerobes,Transfer of “Cellvibrio gilvus” to the Genus Cellulomonas,and Proposal of Cellulomonas gilvus sp. nov

Actinobacteria in the genus Cellulomonas are the only known and reported cellulolytic facultative anaerobes. To better understand the cellulolytic strategy employed by these bacteria, we sequenced the genome of the Cellulomonas fimi ATCC 484^T. For comparative purposes, we also sequenced the genome of the aerobic cellulolytic “Cellvibrio gilvus” ATCC 13127^T. An initial analysis of these genomes using phylogenetic and whole-genome comparison revealed that “Cellvibrio gilvus” belongs to the genus Cellulomonas. We thus propose to assign “Cellvibrio gilvus” to the genus Cellulomonas. A comparative genomics analysis between these two Cellulomonas genome sequences and the recently completed genome for Cellulomonas flavigena ATCC 482^T showed that these cellulomonads do not encode cellulosomes but appear to degrade cellulose by secreting multi-domain glycoside hydrolases. Despite the minimal number of carbohydrate-active enzymes encoded by these genomes, as compared to other known cellulolytic organisms, these bacteria were found to be proficient at degrading and utilizing a diverse set of carbohydrates, including crystalline cellulose. Moreover, they also encode for proteins required for the fermentation of hexose and xylose sugars into products such as ethanol. Finally, we found relatively few significant differences between the predicted carbohydrate-active enzymes encoded by these Cellulomonas genomes, in contrast to previous studies reporting differences in physiological approaches for carbohydrate degradation. Our sequencing and analysis of these genomes sheds light onto the mechanism through which these facultative anaerobes degrade cellulose, suggesting that the sequenced cellulomonads use secreted, multidomain enzymes to degrade cellulose in a way that is distinct from known anaerobic cellulolytic strategies.     

A Multiple Case Study of Mental Health Interventions in Middle Income Countries: Considering the Science of Delivery

In the debate in global mental health about the most effective models for developing and scaling interventions, there have been calls for the development of a more robust literature regarding the "non-specific", science of delivery aspects of interventions that are locally, contextually, and culturally relevant. This study describes a rigorous, exploratory, qualitative examination of the key, non-specific intervention strategies of a diverse group of five internationally-recognized organizations addressing mental illness in middle income countries (MICs). A triangulated approach to inquiry was used with semi-structured interviews conducted with service recipients, service providers and leaders, and key community partners (N = 159). The interview focus was upon processes of implementation and operation. A grounded theory-informed analysis revealed cross cutting themes of: a holistic conceptualization of mental health problems, an intensive application of principles of leverage and creating the social, cultural, and policy “space” within which interventions could be applied and resourced. These findings aligned with key aspects of systems dynamic theory suggesting that it might be a helpful framework in future studies of mental health service implementation in MICs.     

Infarct-induced chronic heart failure increases bidirectional protein movement across the alveolocapillary barrier

Chronic heart failure (CHF) is associated with adaptive structural changes at the alveolocapillary barrier that may be associated with altered protein permeability. Bidirectional protein movement across the barrier was studied in anesthetized rats with infarct-induced CHF by following (125)I-labeled albumin ((125)I-albumin) flux into the alveoli and the leakage of surfactant protein (SP)-B from the alveoli into the circulation. Three groups were studied: controls [0% left ventricular (LV) infarction], moderate infarct (25-45% LV infarction), and large infarct (>46% LV infarction). Wet and dry lung weights increased in the large infarct group (both P < 0.001), consistent with increased lung water and solid lung tissue. (125)I-albumin flux increased across the endothelial (P < 0.001) and epithelial (P < 0.01) components of the alveolocapillary barrier in the large infarct group. Plasma SP-B increased 23% with moderate infarcts (P < 0.05) and 97% with large infarcts (P < 0.001), independent of alveolar levels. Lavage fluid immune cells (P < 0.01) and myeloperoxidase activity (P < 0.05) increased in the large infarct group, consistent with inflammation. Bidirectional protein movement across the alveolocapillary barrier is increased in CHF, and alveolar inflammation may contribute to this pathophysiological defect.     

Inhibition of αIIbβ3 Ligand Binding by an αIIb Peptide that Clasps the Hybrid Domain to the βI Domain of β3

Agonist-stimulated platelet activation triggers conformational changes of integrin αIIbβ3, allowing fibrinogen binding and platelet aggregation. We have previously shown that an octapeptide, ^p1YMESRADR⁸, corresponding to amino acids 313–320 of the β-ribbon extending from the β-propeller domain of αIIb, acts as a potent inhibitor of platelet aggregation. Here we have performed in silico modelling analysis of the interaction of this peptide with αIIbβ3 in its bent and closed (not swing-out) conformation and show that the peptide is able to act as a substitute for the β-ribbon by forming a clasp restraining the β3 hybrid and βI domains in a closed conformation. The involvement of species-specific residues of the β3 hybrid domain (E356 and K384) and the β1 domain (E297) as well as an intrapeptide bond (^pE315-^pR317) were confirmed as important for this interaction by mutagenesis studies of αIIbβ3 expressed in CHO cells and native or substituted peptide inhibitory studies on platelet functions. Furthermore, NMR data corroborate the above results. Our findings provide insight into the important functional role of the αIIb β-ribbon in preventing integrin αIIbβ3 head piece opening, and highlight a potential new therapeutic approach to prevent integrin ligand binding.     

An Insect Herbivore Microbiome with High Plant Biomass-Degrading Capacity

Herbivores can gain indirect access to recalcitrant carbon present in plant cell walls through symbiotic associations with lignocellulolytic microbes. A paradigmatic example is the leaf-cutter ant (Tribe: Attini), which uses fresh leaves to cultivate a fungus for food in specialized gardens. Using a combination of sugar composition analyses, metagenomics, and whole-genome sequencing, we reveal that the fungus garden microbiome of leaf-cutter ants is composed of a diverse community of bacteria with high plant biomass-degrading capacity. Comparison of this microbiome''s predicted carbohydrate-degrading enzyme profile with other metagenomes shows closest similarity to the bovine rumen, indicating evolutionary convergence of plant biomass degrading potential between two important herbivorous animals. Genomic and physiological characterization of two dominant bacteria in the fungus garden microbiome provides evidence of their capacity to degrade cellulose. Given the recent interest in cellulosic biofuels, understanding how large-scale and rapid plant biomass degradation occurs in a highly evolved insect herbivore is of particular relevance for bioenergy.     

The complete genome sequence of Fibrobacter succinogenes S85 reveals a cellulolytic and metabolic specialist

Fibrobacter succinogenes is an important member of the rumen microbial community that converts plant biomass into nutrients usable by its host. This bacterium, which is also one of only two cultivated species in its phylum, is an efficient and prolific degrader of cellulose. Specifically, it has a particularly high activity against crystalline cellulose that requires close physical contact with this substrate. However, unlike other known cellulolytic microbes, it does not degrade cellulose using a cellulosome or by producing high extracellular titers of cellulase enzymes. To better understand the biology of F. succinogenes, we sequenced the genome of the type strain S85 to completion. A total of 3,085 open reading frames were predicted from its 3.84 Mbp genome. Analysis of sequences predicted to encode for carbohydrate-degrading enzymes revealed an unusually high number of genes that were classified into 49 different families of glycoside hydrolases, carbohydrate binding modules (CBMs), carbohydrate esterases, and polysaccharide lyases. Of the 31 identified cellulases, none contain CBMs in families 1, 2, and 3, typically associated with crystalline cellulose degradation. Polysaccharide hydrolysis and utilization assays showed that F. succinogenes was able to hydrolyze a number of polysaccharides, but could only utilize the hydrolytic products of cellulose. This suggests that F. succinogenes uses its array of hemicellulose-degrading enzymes to remove hemicelluloses to gain access to cellulose. This is reflected in its genome, as F. succinogenes lacks many of the genes necessary to transport and metabolize the hydrolytic products of non-cellulose polysaccharides. The F. succinogenes genome reveals a bacterium that specializes in cellulose as its sole energy source, and provides insight into a novel strategy for cellulose degradation.     

The Reactions of Methanimine and Cyanogen with Carbon Monoxide in Prebiotic Molecular Evolution on Earth

A primeval atmosphere is proposedcontaining simple molecules such as formaldehyde, ammonia, carbon monoxide, cyanogen andhydrogen cyanide, which have been detected in space. Chemical reactions aredescribed for the formation ofaziridine-2-one and di-azirine-3-one derivatives aspotential precursors for the original synthesesis of amino-acids, proteins, pyrimidines,purines, nicotinamide and flavin. The reactions have been shown to be kinetically feasiblefrom the overall enthalpy changes in the ZKE approximation at the MP2/6-31G^* level.