Structural and mechanistic basis of RNA processing by protein-only ribonuclease P enzymes

Ribonuclease P (RNase P) enzymes are responsible for the 5′ processing of tRNA precursors. In addition to the well-characterised ribozyme-based RNase P enzymes, an evolutionarily distinct group of protein-only RNase Ps exists. These proteinaceous RNase Ps (PRORPs) can be found in all three domains of life and can be divided into two structurally different types: eukaryotic and pro- karyotic. Recent structural studies on members of both families reveal a surpris- ing diversity of molecular architectures, but also highlight conceptual and mechanistic similarities. Here, we provide a comparison between the different types of PRORP enzymes and review how the combination of structural, bio- chemical, and biophysical studies has led to a molecular picture of protein- mediated tRNA processing

A Beurling algebra is semisimple: an Elementary proof

The Beurling algebra L1(G,ω)on a locally compact Abelian group G with a measurable weight ω is shown to be semisimple. This gives an elementary proof of a result that is implicit in the work of M.C. White (1991), where the arguments are based on amenable (not necessarily Abelian) groups

Traditional uses and relative cultural importance of Tetragonula iridipennis (Smith) (Hymenoptera: Apidae: Meliponini) in Nepal

Indigenous and non-indigenous peoples in tropical and subtropical areas of the world use stingless bees for diverse purposes. Literature records indicate that people from different regions in Nepal use Tetragonula iridipennis (Smith), the only stingless bee species that occurs in the country. However, ethnobiological knowledge on this bee remains poorly documented. Herein we report for the first time on the local indigenous nomenclature, traditional knowledge, and management practices among four ethnic communities (Chhetri, Brahmin, Tharu, and Kirat) in Nepal. We also offer a preliminary quantitative analysis of the relative cultural importance of this species among these ethnic groups. We conducted ethnographic research across the Terai and Pahad regions (8 districts and 6 zones) of Nepal and recorded 18 specific uses in food, medicine, crafts, and religious beliefs. Based on the relative importance index, T. iridipennis is most culturally important for the Tharu people, a finding that supports the reliance of this ethnic group on local natural resources in their everyday life. All participant communities largely exploit this bee through extractive management practice of wild populations. We discuss the conservation status and future directions for the sustainable use of this stingless bee in the country

Understanding Adaptive Capacity: Sustainable Livelihoods and Food Security in Coastal Bangladesh

This paper analyses data from a household-level survey of 980 agricultural and fishing households in seven sites across southern Bangladesh. We examine the relationship between assets, livelihood strategies, food security and farming practice changes. These households are coping with huge demographic, economic, and environmental changes. The results suggest that the least food secure households are also the least adaptive, and are making few, if any changes, in their agricultural practices. They have relatively few assets, and are producing and selling fewer types of agricultural products than more food secure households. The importance of diversification as a strategy to deal with change is evident - households making more farming practice changes are more diversified in terms of the number of different agricultural outputs produced and sold. Market-related factors are more frequently given as reasons for changes in practices than climate-related factors. We also see a strong relationship between education and adaptability. Households with more educated members are likelier to be introducing new agricultural practices. The often unrecognized, but important role that women play in agricultural production and livelihood strategies in Bangladesh is also evident. This rich dataset (freely available at: www.ccafs.cgiar.org/resources/baseline-surveys) provides insights into the relationship between household food security and the agricultural livelihood changes being made by rural households in southern Bangladesh. The analysis provides relatively rare empirical evidence supporting the use of the Sustainable Livelihoods Framework (SLF) as a conceptual approach for understanding household food security as well as adaptation of agriculture to climate change. This information is critical and timely for ongoing dialogues on appropriate ‘climate-resilient’ strategies and policies for increasing the adaptive capacity of households under climate change, and enhancing food security at both household and national levels

Structural basis of RNA processing by human mitochondrial RNase P

Human mitochondrial transcripts contain messenger and ribosomal RNAs flanked by transfer RNAs (tRNAs), which are excised by mitochondrial RNase (mtRNase) P and Z to liberate all RNA species. In contrast to nuclear or bacterial RNase P, mtRNase P is not a ribozyme but comprises three protein subunits that carry out RNA cleavage and methylation by unknown mechanisms. Here, we present the cryo-EM structure of human mtRNase P bound to precursor tRNA, which reveals a unique mechanism of substrate recognition and processing. Subunits TRMT10C and SDR5C1 form a subcomplex that binds conserved mitochondrial tRNA elements, including the anticodon loop, and positions the tRNA for methylation. The endonuclease PRORP is recruited and activated through interactions with its PPR and nuclease domains to ensure precise pre-tRNA cleavage. The structure provides the molecular basis for the first step of RNA processing in human mitochondria

Frechet algebras with a Laurent series generator and the annulus algebras

Banach and Frechet algebras with a Laurent series generator are investigated leading, via the discrete Beurling algebras, to functional analytic characterisations of the holomorphic function algebras on the annulus as well as the C∞-algebra on the unit circle

Mitochondrien: wie die Gene im Kraftwerk der Zelle aktiviert werden

Mitochondria contain an organellar genome that encodes for subunits of the respiratory chain. Its coordinated expression is essential for eukaryotic life and defects in this process lead to severe disease. How- ever, the molecular mechanisms underlying mitochondrial gene expression remain poorly understood. Recent structural and functional studies have provided the first mechanistic insights into mitochondrial gene expression and highlight the evolutionarily unique nature of this system

Agricultural innovation and adaptation to climate change: empirical evidence from diverse agro-ecologies in South Asia

While impacts of climate change on agricultural systems have been widely researched, there is still limited understanding of what agricultural practices evolves over time in response to both climatic and non-climatic drivers and how actors mobilize their resources, institutions and practices in South Asia. Through eight case studies and a survey of300 households in 15 locations in India, Nepal and Bangladesh, this paper generates empirical evidence on emerging agricultural interventions in contrasting socio-economic, geographical and agro-ecological contexts. The study shows that several farm practices emerge out in response to multiple drivers over time; some of them can be further adjusted to the challenge of climate change by planned adaptation programs. Most actors, however, have considered private risks in the short run. Although there has been some progress in streamlining climate change into strategic planning in different countries of South Asia, policy, research and extension systems lack adequate attention to wider resilience of the system. Based on this analysis, we recommend that adaptation policies should complement farmers’ responses to climate change through informed research and extension systems and pro-poor government policies that improve adaptation and coordinate activities of different actors

Association of Panton Valentine Leukocidin (PVL) genes with methicillin resistant Staphylococcus aureus (MRSA) in Western Nepal: a matter of concern for community infections (a hospital based prospective study)

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apoptosis and as a marker of community acquired MRSA. This study was aimed to determine the prevalence of PVL genes among MRSA isolates and to check the reliability of PVL as marker of community acquired MRSA isolates from Western Nepal. METHODS: A total of 400 strains of S. aureus were collected from clinical specimens and various units (Operation Theater, Intensive Care Units) of the hospital and 139 of these had been confirmed as MRSA by previous study. Multiplex PCR was used to detect mecA and PVL genes. Clinical data as well as antimicrobial susceptibility data was analyzed and compared among PVL positive and negative MRSA isolates. RESULTS: Out of 139 MRSA isolates, 79 (56.8 %) were PVL positive. The majority of the community acquired MRSA (90.4 %) were PVL positive (Positive predictive value: 94.9 % and negative predictive value: 86.6 %), while PVL was detected only in 4 (7.1 %) hospital associated MRSA strains. None of the MRSA isolates from hospital environment was found positive for the PVL genes. The majority of the PVL positive strains (75.5 %) were isolated from pus samples. Antibiotic resistance among PVL negative MRSA isolates was found higher as compared to PVL positive MRSA. CONCLUSION: Our study showed high prevalence of PVL among community acquired MRSA isolates. Absence of PVL among MRSA isolates from hospital environment indicates its poor association with hospital acquired MRSA and therefore, PVL may be used a marker for community acquired MRSA. This is first study from Nepal, to test PVL among MRSA isolates from hospital environment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-016-1531-1) contains supplementary material, which is available to authorized users

A guide to the processing and standardization of global palaeoecological data for large-scale syntheses using fossil pollen

Aim: Palaeoecological data are crucial for comprehending large-scale biodiversity patterns and the natural and anthropogenic drivers that influence them over time. Over the last decade, the availability of open-access research databases of palaeoecological proxies has substantially increased. These databases open the door to research questions needing advanced numerical analyses and modelling based on big-data compilations. However, compiling and analysing palaeoecological data pose unique challenges that require a guide for producing standardized and reproducible compilations. Innovation: We present a step-by-step guide of how to process fossil pollen data into a standardized dataset compilation ready for macroecological and palaeoecological analyses. We describe successive criteria that will enhance the quality of the compilations. Though these criteria are project and research question-dependent, we discuss the most important assumptions that should be considered and adjusted accordingly. Our guide is accompanied by an R-workflow—called FOSSILPOL—and corresponding R-package—called R-Fossilpol—that provide a detailed protocol ready for interdisciplinary users. We illustrate the workflow by sourcing and processing Scandinavian fossil pollen datasets and show the reproducibility of continental-scale data processing. Main Conclusions: The study of biodiversity and macroecological patterns through time and space requires large-scale syntheses of palaeoecological datasets. The data preparation for such syntheses must be transparent and reproducible. With our FOSSILPOL workflow and R-package, we provide a protocol for optimal handling of large compilations of fossil pollen datasets and workflow reproducibility. Our workflow is also relevant for the compilation and synthesis of other palaeoecological proxies and as such offers a guide for synthetic and cross-disciplinary analyses with macroecological, biogeographical and palaeoecological perspectives. However, we emphasize that expertise and informed decisions based on palaeoecological knowledge remain crucial for high-quality data syntheses and should be strongly embedded in studies that rely on the increasing amount of open-access palaeoecological data.publishedVersio