140 research outputs found
A Genome-scale CRISPR Screen Identifies the ERBB and mTOR Signaling Networks as Key Determinants of Response to PI3K Inhibition in Pancreatic Cancer.
KRAS mutation is a key driver of pancreatic cancer and PI3K pathway activity is an additional requirement for Kras-induced tumorigenesis. Clinical trials of PI3K pathway inhibitors in pancreatic cancer have shown limited responses. Understanding the molecular basis for this lack of efficacy may direct future treatment strategies with emerging PI3K inhibitors. We sought new therapeutic approaches that synergize with PI3K inhibitors through pooled CRISPR modifier genetic screening and a drug combination screen. ERBB family receptor tyrosine kinase signaling and mTOR signaling were key modifiers of sensitivity to alpelisib and pictilisib. Inhibition of the ERBB family or mTOR was synergistic with PI3K inhibition in spheroid, stromal cocultures. Near-complete loss of ribosomal S6 phosphorylation was associated with synergy. Genetic alterations in the ERBB-PI3K signaling axis were associated with decreased survival of patients with pancreatic cancer. Suppression of the PI3K/mTOR axis is potentiated by dual PI3K and ERBB family or mTOR inhibition. Surprisingly, despite the presence of oncogenic KRAS, thought to bestow independence from receptor tyrosine kinase signaling, inhibition of the ERBB family blocks downstream pathway activation and synergizes with PI3K inhibitors. Further exploration of these therapeutic combinations is warranted for the treatment of pancreatic cancer
Breeding systems in Tolpis (Asteraceae) in the Macaronesian islands: the Azores, Madeira and the Canaries
Plants on oceanic islands often originate from
self-compatible (SC) colonizers capable of seed set by self fertilization. This fact is supported by empirical studies,
and is rooted in the hypothesis that one (or few) individuals
could find a sexual population, whereas two or more would
be required if the colonizers were self-incompatible (SI).
However, a SC colonizer would have lower heterozygosity
than SI colonizers, which could limit radiation and diver sification of lineages following establishment. Limited
evidence suggests that several species-rich island lineages
in the family Asteraceae originated from SI colonizers with
some ‘‘leakiness’’ (pseudo-self-compatibility, PSC) such
that some self-seed could be produced. This study of Tolpis
(Asteraceae) in Macaronesia provides first reports of the
breeding system in species from the Azores and Madeira,
and additional insights into variation in Canary Islands.
Tolpis from the Azores and Madeira are predominately SI
but with PSC. This study suggests that the breeding sys tems of the ancestors were either PSC, possibly from a
single colonizer, or from SI colonizers by multiple dis seminules either from a single or multiple dispersals. Long distance colonists capable of PSC combine the advantages
of reproductive assurance (via selfing) in the establishment
of sexual populations from even a single colonizer with the
higher heterozygosity resulting from its origin from an
outcrossed source population. Evolution of Tolpis on the
Canaries and Madeira has generated diversity in breeding
systems, including the origin of SC. Macaronesian Tolpis is
an excellent system for studying breeding system evolution
in a small, diverse lineage.info:eu-repo/semantics/publishedVersio
Rethinking the study of human-wildlife coexistence
While coexistence with wildlife is a key goal of conservation efforts, little is known about it or how to study it. This essay briefly defines what we mean by coexistence, before considering issues arising from the conflict-oriented framing of human-wildlife interactions within conservation science. It proposes reasons for why conflict frameworks persist – and why much less work is done on coexistence. Methodological and fieldwork challenges for studying coexistence are outlined, with recommendations, based on the authors’ teaching experience and field experience in India and Africa. We recommend expanding the scope of our inquiries into the ways in which humans and wildlife already coexist beyond studies of rational behaviour, and the quantification of costs and benefits of wildlife to humans
Simple large wood structures promote hydromorphological heterogeneity and benthic macroinvertebrate diversity in low-gradient rivers
This work has been carried out within the SMART Joint Doctorate Programme ‘Science for the MAnagement of Rivers and their Tidal systems’ funded by the Erasmus Mundus programme of the European Union
Historical Legacies in World Amphibian Diversity Revealed by the Turnover and Nestedness Components of Beta Diversity
Historic processes are expected to influence present diversity patterns in combination with contemporary environmental factors. We hypothesise that the joint use of beta diversity partitioning methods and a threshold-based approach may help reveal the effect of large-scale historic processes on present biodiversity. We partitioned intra-regional beta diversity into its turnover (differences in composition caused by species replacements) and nestedness-resultant (differences in species composition caused by species losses) components. We used piecewise regressions to show that, for amphibian beta diversity, two different world regions can be distinguished. Below parallel 37, beta diversity is dominated by turnover, while above parallel 37, beta diversity is dominated by nestedness. Notably, these regions are revealed when the piecewise regression method is applied to the relationship between latitude and the difference between the Last Glacial Maximum (LGM) and the present temperature but not when present energy-water factors are analysed. When this threshold effect of historic climatic change is partialled out, current energy-water variables become more relevant to the nestedness-resultant dissimilarity patterns, while mountainous areas are associated with higher spatial turnover. This result suggests that nested patterns are caused by species losses that are determined by physiological constraints, whereas turnover is associated with speciation and/or Pleistocene refugia. Thus, the new threshold-based view may help reveal the role of historic factors in shaping present amphibian beta diversity patterns
Molecular Mining of Alleles in Water Buffalo Bubalus bubalis and Characterization of the TSPY1 and COL6A1 Genes
discovered in the process. gene in water buffalo, which localized to the Y chromosome.The MASA approach enabled us to identify several genes, including two of clinical significance, without screening an entire cDNA library. Genes identified with TGG repeats are not part of a specific family of proteins and instead are distributed randomly throughout the genome. Genes showing elevated expression in the testes and spermatozoa may prove to be potential candidates for in-depth characterization. Furthermore, their possible involvement in fertility or lack thereof would augment animal biotechnology
Home Telehealth Uptake and Continued Use Among Heart Failure and Chronic Obstructive Pulmonary Disease Patients: a Systematic Review
Background
Home telehealth has the potential to benefit heart failure (HF) and chronic obstructive pulmonary disease (COPD) patients, however large-scale deployment is yet to be achieved.
Purpose
The aim of this review was to assess levels of uptake of home telehealth by patients with HF and COPD and the factors that determine whether patients do or do not accept and continue to use telehealth.
Methods
This research performs a narrative synthesis of the results from included studies.
Results
Thirty-seven studies met the inclusion criteria. Studies that reported rates of refusal and/or withdrawal found that almost one third of patients who were offered telehealth refused and one fifth of participants who did accept later abandoned telehealth. Seven barriers to, and nine facilitators of, home telehealth use were identified.
Conclusions
Research reports need to provide more details regarding telehealth refusal and abandonment, in order to understand the reasons why patients decide not to use telehealth
The Nature Index: A General Framework for Synthesizing Knowledge on the State of Biodiversity
The magnitude and urgency of the biodiversity crisis is widely recognized within
scientific and political organizations. However, a lack of integrated measures
for biodiversity has greatly constrained the national and international response
to the biodiversity crisis. Thus, integrated biodiversity indexes will greatly
facilitate information transfer from science toward other areas of human
society. The Nature Index framework samples scientific information on
biodiversity from a variety of sources, synthesizes this information, and then
transmits it in a simplified form to environmental managers, policymakers, and
the public. The Nature Index optimizes information use by incorporating expert
judgment, monitoring-based estimates, and model-based estimates. The index
relies on a network of scientific experts, each of whom is responsible for one
or more biodiversity indicators. The resulting set of indicators is supposed to
represent the best available knowledge on the state of biodiversity and
ecosystems in any given area. The value of each indicator is scaled relative to
a reference state, i.e., a predicted value assessed by each expert for a
hypothetical undisturbed or sustainably managed ecosystem. Scaled indicator
values can be aggregated or disaggregated over different axes representing
spatiotemporal dimensions or thematic groups. A range of scaling models can be
applied to allow for different ways of interpreting the reference states, e.g.,
optimal situations or minimum sustainable levels. Statistical testing for
differences in space or time can be implemented using Monte-Carlo simulations.
This study presents the Nature Index framework and details its implementation in
Norway. The results suggest that the framework is a functional, efficient, and
pragmatic approach for gathering and synthesizing scientific knowledge on the
state of biodiversity in any marine or terrestrial ecosystem and has general
applicability worldwide
Negative feedback regulation of the ERK1/2 MAPK pathway
The extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signalling pathway regulates many cellular functions, including proliferation, differentiation, and transformation. To reliably convert external stimuli into specific cellular responses and to adapt to environmental circumstances, the pathway must be integrated into the overall signalling activity of the cell. Multiple mechanisms have evolved to perform this role. In this review, we will focus on negative feedback mechanisms and examine how they shape ERK1/2 MAPK signalling. We will first discuss the extensive number of negative feedback loops targeting the different components of the ERK1/2 MAPK cascade, specifically the direct posttranslational modification of pathway components by downstream protein kinases and the induction of de novo gene synthesis of specific pathway inhibitors. We will then evaluate how negative feedback modulates the spatiotemporal signalling dynamics of the ERK1/2 pathway regarding signalling amplitude and duration as well as subcellular localisation. Aberrant ERK1/2 activation results in deregulated proliferation and malignant transformation in model systems and is commonly observed in human tumours. Inhibition of the ERK1/2 pathway thus represents an attractive target for the treatment of malignant tumours with increased ERK1/2 activity. We will, therefore, discuss the effect of ERK1/2 MAPK feedback regulation on cancer treatment and how it contributes to reduced clinical efficacy of therapeutic agents and the development of drug resistance
- …