Nodule development on the tropical legume Sesbania virgata under flooded and non‐flooded conditions

The interaction between the Brazilian pioneer legume Sesbania virgata and its microsymbiont Azorhizobium doebereinerae leads to the formation of nitrogen‐fixing nodules on roots that grow either in well‐aerated soils or in wetlands. We studied the initiation and development of nodules under these alternative conditions. To this end, light and fluorescence microscopy were used to follow the bacterial colonisation and invasion into the host and, by means of transmission electron microscopy, we could observe the intracellular entry. Under hydroponic conditions, intercellular invasion took place at lateral root bases and mature nodules were round and determinate. However, on roots grown in vermiculite that allows aerated growth, bacteria also entered via root hair invasion and nodules were both of the determinate and indeterminate type. Such versatility in entry and developmental plasticity, as previously described in Sesbania rostrata, enables efficient nodulation in both dry and wet environments and are an important adaptive feature of this group of semi‐tropical plants that grow in temporarily flooded habitats.     

Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions

Aim We use data from 13 mountain regions and surrounding lowland areas to identify (1) the origins, traits and cultural uses of alien plant species that establish in mountains, (2) the alien species that are most likely to be a threat and (3) how managers might use this information to prevent further invasions. Location Australia, Canada, Chile, India, New Zealand, South Africa, Spain, Switzerland, USA. Methods Lists of alien species were compiled for mountains and their surrounding or nearby lowlands. Principal co‐ordinates analysis was performed on a matrix of similarities created using presence/absence data for alien species. The significance of differences between means for (1) similarity metrics of lowland and mountain groups and (2) species traits of lowland and mountain alien floras was determined using t‐tests. In seven of the 13 mountain regions, lists of alien species undergoing management were compiled. The significance of differences between proportions of traits for species requiring and not requiring management input was determined with chi‐square tests. Results We found that the proximal lowland alien flora is the main determinant of a mountain region’s alien species composition. The highest similarities between mountain floras were in the Americas/Pacific Region. The majority of alien species commonly found in mountains have agricultural origins and are of little concern to land managers. Woody species and those used for ornamental purposes will often pose the greatest threat. Main conclusions Given the documented potential threat of alien species invading mountains, we advise natural resource managers to take preventive measures against the risk of alien plant invasion in mountains. A strategy for prevention should extend to the surrounding lowland areas and in particular regulate the introduction of species that are already of management concern in other mountains as well as climatically pre‐adapted alien mountain plants. These may well become more problematic than the majority of alien plants currently in mountains.     

Successful spread of a biocontrol agent reveals a biosecurity failure: elucidating long distance invasion pathways for <Emphasis Type="Italic">Gonatocerus ashmeadi</Emphasis> in French Polynesia

Invasive species are generally detected in new ecosystems long after their first arrival, making it difficult to elucidate pathways leading to successful invasion. In this study, the dispersal of a classical biological control agent, the mymarid egg parasitoid Gonatocerus ashmeadi, was monitored across ten islands in three major island groups in French Polynesia from the exact moment of its introduction into Tahiti to combat the invasive pest Homalodisca vitripennis. Within 10 months, the parasitoid spread quickly from Tahiti to widely separated islands (up to 1,400 km from Tahiti); presumably through the transportation of plant material containing parasitized H. vitripennis eggs. Gonatocerus ashmeadi thus functioned as a “biomarker”, providing an informal audit of the effectiveness of inter-island quarantine measures designed to curb the accidental spread of noxious organisms. Survey results suggest that invasive organisms, like deliberately released biological control agents, can be unintentionally and rapidly transmitted across vast distances by humans. Furthermore, even remote islands appear to experience relentless pressure from invasive propagules associated with human travel. Implications of survey work documenting the spread and impact of G. ashmeadi are discussed within the context of biological control programs, non-target impacts, and biosecurity initiatives. Handling Editor: Dirk Babendreier.     

Projecting impacts of global climate and land‐use scenarios on plant biodiversity using compositional‐turnover modelling

Nations have committed to ambitious conservation targets in response to accelerating rates of global biodiversity loss. Anticipating future impacts is essential to inform policy decisions for achieving these targets, but predictions need to be of sufficiently high spatial resolution to forecast the local effects of global change. As part of the intercomparison of biodiversity and ecosystem services models of the Intergovernmental Science‐Policy Platform on Biodiversity and Ecosystem Services, we present a fine‐resolution assessment of trends in the persistence of global plant biodiversity. We coupled generalized dissimilarity models, fitted to >52 million records of >254 thousand plant species, with the species–area relationship, to estimate the effect of land‐use and climate change on global biodiversity persistence. We estimated that the number of plant species committed to extinction over the long term has increased by 60% globally between 1900 and 2015 (from ~10,000 to ~16,000). This number is projected to decrease slightly by 2050 under the most optimistic scenario of land‐use change and to substantially increase (to ~18,000) under the most pessimistic scenario. This means that, in the absence of climate change, scenarios of sustainable socio‐economic development can potentially bring extinction risk back to pre‐2000 levels. Alarmingly, under all scenarios, the additional impact from climate change might largely surpass that of land‐use change. In this case, the estimated number of species committed to extinction increases by 3.7–4.5 times compared to land‐use‐only projections. African regions (especially central and southern) are expected to suffer some of the highest impacts into the future, while biodiversity decline in Southeast Asia (which has previously been among the highest globally) is projected to slow down. Our results suggest that environmentally sustainable land‐use planning alone might not be sufficient to prevent potentially dramatic biodiversity loss, unless a stabilization of climate to pre‐industrial times is observed.     

湛江市外来植物入侵状况

[目的]了解湛江市外来入侵植物的种类特征、生活型、起源和危害情况等,对制定预防和控制管理措施提供参考。[方法]以野外调查为主,结合文献资料、网络资源以及标本数据,确定湛江市外来入侵植物的种类、生活型、原产地、引入途径,并进行评估及划分危害等级。[结果]湛江市现有外来入侵植物共112种(含变种),隶属于37科89属,其中,菊科(21种)、禾本科(13种)和豆科(13种)为种类较多的3个科,三者合计占湛江市外来入侵植物总种数的41.96%。湛江市外来入侵植物中以草本植物居多(98种),占入侵植物总数的87.50%。入侵植物主要来源于美洲,共82种,占总种数的73.21%;且55.36%(62种)的入侵植物为有意引入。从危害等级看,外来入侵植物中恶性入侵种(1级)23种,严重入侵种(2级)35种,局部入侵种(3级)21种,一般入侵种(4级)15种,有待观察种(5级)18种。[结论]湛江市的外来入侵植物种类繁多,这与湛江独特的地理位置以及日趋频繁的人类活动息息相关,应当加强监管与防范,及时对外来物种进行治理。     

MicroRNA-196a promotes renal cancer cell migration and invasion by targeting BRAM1 to regulate SMAD and MAPK signaling pathways

Rationale: MicroRNAs (miRNAs) are endogenous ~22nt RNAs that play critical regulatory roles in various biological and pathological processes, including various cancers. Their function in renal cancer has not been fully elucidated. It has been reported that miR-196a can act as oncogenes or as tumor suppressors depending on their target genes. However, the molecular target for miR-196a and the underlying mechanism in miR-196a promoted cell migration and invasion in renal cancer is still not clear.Methods: The expression, survival and correlation between miR-196a and BRAM1 were investigated using TCGA analysis and validated by RT-PCR and western blot. To visualize the effect of Bram1 on tumor metastasis in vivo, NOD-SCID gamma (NSG) mice were intravenously injected with RCC4 cells (10⁶ cells/mouse) or RCC4 overexpressing Bram1. In addition, cell proliferation assays, migration and invasion assays were performed to examine the role of miR-196a in renal cells in vitro. Furthermore, immunoprecipitation was done to explore the binding targets of Bram1.Results: TCGA gene expression data from renal clear cell carcinoma patients showed a lower level of Bram1 expression in patients'' specimens compared to adjacent normal tissues. Moreover, Kaplan‑Meier survival data clearly show that high expression of Bram1correlates to poor prognosis in renal carcinoma patients. Our mouse metastasis model confirmed that Bram1 overexpression resulted in an inhibition in tumor metastasis. Target-prediction analysis and dual-luciferase reporter assay demonstrated that Bram1 is a direct target of miR-196a in renal cells. Further, our in vitro functional assays revealed that miR-196a promotes renal cell proliferation, migration, and invasion. Rescue of Bram1 expression reversed miR-196a-induced cell migration. MiR-196a promotes renal cancer cell migration by directly targeting Bram1 and inhibits Smad1/5/8 phosphorylation and MAPK pathways through BMPR1A and EGFR.Conclusions: Our findings thus provide a new mechanism on the oncogenic role of miR-196a and the tumor-suppressive role of Bram1 in renal cancer cells. Dysregulated miR-196a and Bram1 represent potential prognostic biomarkers and may have therapeutic applications in renal cancer.     

Importance of plant‐ and microbe‐driven metabolic pathways for plant defence

Expression of plant phenotypes can depend on both plant genomes and interactions between plants and the microbes living in, on and near their roots. We understand a growing number of the mechanistic links between plant genotypes and phenotypes, such as defence against herbivory (see brief review in Hubbard et al., 2019), yet the links between root microbiomes and the comprehensive swathe of plant phenotypes they affect (Friesen et al., 2011) remain less clear. In this issue of Molecular Ecology, Hubbard et al. (2019) follow microbe‐ and plant‐driven changes in plant defence against hervibory from molecular underpinnings to ecological consequences, contrasting both the metabolites affected and the magnitude of defensive impact. Naively, we might expect plant genomes to drive more variation in phenotype than the root microbiome, but Hubbard et al. (2019) find the opposite, implying profound consequences for plant trait evolution and ecological interactions.     

Current knowledge on non‐native freshwater fish introductions

This review provides a contemporary account of knowledge on aspects of introductions of non‐native fish species and includes issues associated with introduction pathways, ecological and economic impacts, risk assessments, management options and impact of climate change. It offers guidance to reconcile the increasing demands of certain stakeholders to diversify their activities using non‐native fishes with the long‐term sustainability of native aquatic biodiversity. The rate at which non‐native freshwater fishes have been introduced worldwide has doubled in the space of 30 years, with the principal motives being aquaculture (39%) and improvement of wild stocks (17%). Economic activity is the principal driver of human‐mediated non‐native fish introductions, including the globalization of fish culture, whereby the production of the African cichlid tilapia is seven times higher in Asia than in most areas of Africa, and Chile is responsible for c. 30% of the world's farmed salmon, all based on introduced species. Consequently, these economic benefits need balancing against the detrimental environmental, social and economic effects of introduced non‐native fishes. There are several major ecological effects associated with non‐native fish introductions, including predation, habitat degradation, increased competition for resources, hybridization and disease transmission. Consideration of these aspects in isolation, however, is rarely sufficient to adequately characterize the overall ecological effect of an introduced species. Regarding the management of introduced non‐native fish, pre‐introduction screening tools, such as the fish invasiveness scoring kit (FISK), can be used to ensure that species are not introduced, which may develop invasive populations. Following the introduction of non‐native fish that do develop invasive populations, management responses are typified by either a remediation or a mitigation response, although these are often difficult and expensive to implement, and may have limited effectiveness.     

Impact of Vitamin D Supplementation on Inflammatory Markers’ Levels in Obese Patients

In view of research suggesting a possible beneficial impact of vitamin D on systemic inflammatory response, the authors decided to investigate an influence of vitamin D supplementation on serum levels of certain inflammatory markers in obese patients. The current study included such biomarkers as interleukin-6 (IL-6), pituitary adenylate cyclase-activating peptide (PACAP), advanced oxidation protein products (AOPP), C-X3-C Motif Chemokine Ligand 1 (CX3CL1), monocyte chemoattractant protein-1 (MCP-1), and nitric oxide (NO). The measurements were performed with the ELISA method before and after 3-month-long supplementation of 2000 IU of vitamin D orally. The results showed that the therapy did not induce any statistically significant changes in serum levels of MCP-1, IL-6, CX3CL1, and PACAP. The supplementation was related to a significant increase in measurements of NO and AOPP levels, although the correlation analysis between vitamin D concentration after its supplementation and the concentration of the molecular parameters did not show significant relation. In conclusion, our study seems to contradict certain aspects of findings available in the literature regarding the vitamin D’s impact.     

Signalling pathways involved in hypoxia‐induced renal fibrosis

Renal fibrosis is the common pathological hallmark of progressive chronic kidney disease (CKD) with diverse aetiologies. Recent researches have highlighted the critical role of hypoxia during the development of renal fibrosis as a final common pathway in end‐stage kidney disease (ESKD), which joints the scientist's attention recently to exploit the molecular mechanism underlying hypoxia‐induced renal fibrogenesis. The scaring formation is a multilayered cellular response and involves the regulation of multiple hypoxia‐inducible signalling pathways and complex interactive networks. Therefore, this review will focus on the signalling pathways involved in hypoxia‐induced pathogenesis of interstitial fibrosis, including pathways mediated by HIF, TGF‐β, Notch, PKC/ERK, PI3K/Akt, NF‐κB, Ang II/ROS and microRNAs. Roles of molecules such as IL‐6, IL‐18, KIM‐1 and ADO are also reviewed. A comprehensive understanding of the roles that these hypoxia‐responsive signalling pathways and molecules play in the context of renal fibrosis will provide a foundation towards revealing the underlying mechanisms of progression of CKD and identifying novel therapeutic targets. In the future, promising new effective therapy against hypoxic effects may be successfully translated into the clinic to alleviate renal fibrosis and inhibit the progression of CKD.     

Interceptions of Nonindigenous Plant Pests at US Ports of Entry and Border Crossings Over a 17-year Period

Despite the substantial impacts of nonindigenous plant pests and weeds, relatively little is known about the pathways by which these organisms arrive in the U.S. One source of such information is the Port Information Network (PIN) database, maintained by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) since 1984. The PIN database is comprised of records of pests intercepted by APHIS personnel during inspections of travelers’ baggage, cargo, conveyances and related items arriving at U.S. ports of entry and border crossings. Each record typically includes the taxonomic identify of the pest, its country of origin, and information related to the commodity and interception site. We summarized more than 725,000 pest interceptions recorded in PIN from 1984 to 2000 to examine origins, interception sites and modes of transport for nonindigenous insects, mites, mollusks, nematodes, plant pathogens and weeds. Roughly 62% of intercepted pests were associated with baggage, 30% were associated with cargo and 7% were associated with plant propagative material. Pest interceptions occurred most commonly at airports (73%), U.S.-Mexico land border crossings (13%) and marine ports (9%). Insects dominated the database, comprising 73 to 84% of the records annually, with the orders Homoptera, Lepidoptera and Diptera collectively accounting for over 75% of the insect records. Plant pathogens, weeds and mollusks accounted for 13, 7 and 1.5% of all pest records, respectively, while mites and nematodes comprised less than 1% of the records. Pests were intercepted from at least 259 different locations. Common origins included Mexico, Central and South American countries, the Caribbean and Asia. Within specific commodity pathways, richness of the pest taxa generally increased linearly with the number of interceptions. Application of PIN data for statistically robust predictions is limited by nonrandom sampling protocols, but the data provide a valuable historical record of the array of nonindigenous organisms transported to the U.S. through international trade and travel.     

“Cancer Reviews 2021” series: Dynamic EMT: a multi‐tool for tumor progression

The process of epithelial–mesenchymal transition (EMT) is fundamental for embryonic morphogenesis. Cells undergoing it lose epithelial characteristics and integrity, acquire mesenchymal features, and become motile. In cancer, this program is hijacked to confer essential changes in morphology and motility that fuel invasion. In addition, EMT is increasingly understood to orchestrate a large variety of complementary cancer features, such as tumor cell stemness, tumorigenicity, resistance to therapy and adaptation to changes in the microenvironment. In this review, we summarize recent findings related to these various classical and non‐classical functions, and introduce EMT as a true tumorigenic multi‐tool, involved in many aspects of cancer. We suggest that therapeutic targeting of the EMT process will—if acknowledging these complexities—be a possibility to concurrently interfere with tumor progression on many levels.