Molecular genetics and comparative genomics reveal RNAi is not functional in malaria parasites

Techniques for targeted genetic disruption in Plasmodium, the causative agent of malaria, are currently intractable for those genes that are essential for blood stage development. The ability to use RNA interference (RNAi) to silence gene expression would provide a powerful means to gain valuable insight into the pathogenic blood stages but its functionality in Plasmodium remains controversial. Here we have used various RNA-based gene silencing approaches to test the utility of RNAi in malaria parasites and have undertaken an extensive comparative genomics search using profile hidden Markov models to clarify whether RNAi machinery exists in malaria. These investigative approaches revealed that Plasmodium lacks the enzymology required for RNAi-based ablation of gene expression and indeed no experimental evidence for RNAi was observed. In its absence, the most likely explanations for previously reported RNAi-mediated knockdown are either the general toxicity of introduced RNA (with global down-regulation of gene expression) or a specific antisense effect mechanistically distinct from RNAi, which will need systematic analysis if it is to be of use as a molecular genetic tool for malaria parasites.     

Climate change, conservation and management: an assessment of the peer-reviewed scientific journal literature

Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change, similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species. Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper our ability to make useful recommendations in a world that is experiencing significant global change.     

Gene mapping in the wild with SNPs: guidelines and future directions

One of the biggest challenges facing evolutionary biologists is to identify and understand loci that explain fitness variation in natural populations. This review describes how genetic (linkage) mapping with single nucleotide polymorphism (SNP) markers can lead to great progress in this area. Strategies for SNP discovery and SNP genotyping are described and an overview of how to model SNP genotype information in mapping studies is presented. Finally, the opportunity afforded by new generation sequencing and typing technologies to map fitness genes by genome-wide association studies is discussed.     

The role of bioclimatic origin,residence time and habitat context in shaping non-native plant distributions along an altitudinal gradient

An important factor influencing whether or not a non-native plant species becomes invasive is the climate in the area of introduction. To become naturalised in the new range, a species must either be climatically pre-adapted (climate matching), have a high phenotypic plasticity, or be able to adapt genetically, which in the latter case may take many generations. Furthermore, patterns of successful establishment across species might vary with habitat context. To address the interaction of these factors on non-native species richness, we recorded the presence of non-native annual plant species along an altitudinal gradient on Tenerife (Canary Islands, Spain). We compared the distributions of species differing in bioclimatic origin (Mediterranean and temperate) and time since introduction (old and recent introductions), and compared richness patterns of these groups in anthropogenic and natural habitats. Non-native species richness increased strongly from lowlands to mid-altitudes, but dropped sharply at the transition from anthropogenic to natural habitats, and thereafter declined with altitude in the natural habitat. This pattern indicates that the altitude effects reflected changes in both climate and habitat context. Mediterranean and temperate species were distributed similarly along the altitudinal gradient, and we found no effect of bioclimatic origin on species distributions. As almost all species present at the highest sites also occurred in the lowlands, we conclude that most species were introduced to lowland sites and were therefore pre-adapted to those climatic conditions (lowland introduction filter). The altitudinal ranges of species tended to increase with time since introduction, and the species reaching the highest altitudes were mostly old introductions. This effect of time was more pronounced among Mediterranean than temperate species. Thus, while climatic pre-adaptation is important for establishment along this altitudinal gradient, species tend to extend their altitudinal range with time.     

A Framework for Evaluating Heterogeneity and Landscape-Level Impacts of Non-native Aquatic Species

Non-native species are a major component of global environmental change, and aquatic systems are especially vulnerable to non-native species impacts. Much of the research on aquatic non-native species impact has occurred at the local or site level. In reality, non-native species impacts play out across multiple spatial scales on heterogeneous landscapes. How can we ‘scale up’ our understanding of site-level impacts to the broader landscape scale? To address this disconnect, we synthesize our current understanding of key components of landscape-scale non-native species impacts: geographic range, abundance, and local impacts. Most aquatic non-native species have small ranges, while a few have large ranges. However, aquatic non-native species are often far from saturated on landscapes, and occurrence records are often woefully incomplete. Aquatic non-native species are often at low abundances where they are present, reaching high abundance in a small number of locations. Finally, local-scale impact can be estimated from abundance, but this requires knowledge of the abundance–impact relationship. Considering these multiple components enables understanding of non-native species impacts at broader spatial scales. Although the landscape-level impacts of aquatic non-native species may be high, the spatial distribution of site-level impacts is uneven, and highly impacted sites may be relatively uncommon. This heterogeneity in impacts provides an opportunity to optimize and prioritize non-native species management and prevention efforts.     

The growing field of digital psychiatry: current evidence and the future of apps,social media,chatbots, and virtual reality

As the COVID‐19 pandemic has largely increased the utilization of telehealth, mobile mental health technologies – such as smartphone apps, vir­tual reality, chatbots, and social media – have also gained attention. These digital health technologies offer the potential of accessible and scalable interventions that can augment traditional care. In this paper, we provide a comprehensive update on the overall field of digital psychiatry, covering three areas. First, we outline the relevance of recent technological advances to mental health research and care, by detailing how smartphones, social media, artificial intelligence and virtual reality present new opportunities for “digital phenotyping” and remote intervention. Second, we review the current evidence for the use of these new technological approaches across different mental health contexts, covering their emerging efficacy in self‐management of psychological well‐being and early intervention, along with more nascent research supporting their use in clinical management of long‐term psychiatric conditions – including major depression; anxiety, bipolar and psychotic disorders; and eating and substance use disorders – as well as in child and adolescent mental health care. Third, we discuss the most pressing challenges and opportunities towards real‐world implementation, using the Integrated Promoting Action on Research Implementation in Health Services (i‐PARIHS) framework to explain how the innovations themselves, the recipients of these innovations, and the context surrounding innovations all must be considered to facilitate their adoption and use in mental health care systems. We conclude that the new technological capabilities of smartphones, artificial intelligence, social media and virtual reality are already changing mental health care in unforeseen and exciting ways, each accompanied by an early but promising evidence base. We point out that further efforts towards strengthening implementation are needed, and detail the key issues at the patient, provider and policy levels which must now be addressed for digital health technologies to truly improve mental health research and treatment in the future.     

Ecological and genetic assessment of spatial structure among replicate contact zones between two topminnow species

The spatial structure of contact zones is often described as disjunct, diffuse or mosaic and presumed to be related to underlying ecological gradients. However, the ecology of contact zones, how they are structured, and if that structure is predictable based on the strength and nature of ecological gradients is unknown. Large spatial scales and the unreplicated nature of many of the best studied contact zones has made it difficult to codify broader ecological patterns. Freshwater stream fish contact zones have the advantage of being potentially replicated with well defined boundaries and predictable linear gradients (river continuum concept). We sampled four replicate topminnow (Fundulus olivaceus and F. notatus) contact zones in Gulf of Mexico drainages. In each, we quantified contact zone spatial structure and the strength of ecological gradients (habitat, physicochemical variables and fish community functional traits). All three types of contact zone structure were represented. Systems with weaker gradients had diffuse contact zones, low species richness and were numerically dominated by generalist species. Rates of hybridization were also variable among systems. There was no hybridization detected in the mosaic zone while hybrids were found at most of the co-occurrence sites in the diffuse and disjunct zones. Overall, local ecology clearly influences contact zone structure and the two species interact in fundamentally different ways in these four systems.