Idea paper: Monitoring and databasing non-native species to manage establishment debt in aquatic ecosystems

In the era of globalization, biological invasions are one of the most serious social issues. Thus, managing its impact is an urgent task. It is essential to control non-native species before they become established. However, it is insufficient to address establishment debt, which occurs when a non-native species has been introduced into an area but has not yet been established in the wild. In particular, unintentionally introduced or contaminated organisms of the aquatic ornamental pet trade are referred to as “hitchhikers” and have not received much attention in the context of establishment debt. To understand the nature of establishment debt, including that of aquatic hitchhikers, I propose the monitoring of non-native species inhabiting artificial isolated waters, such as indoor aquariums, and the construction of a database using environmental DNA metabarcoding. This idea would be an effective non-regulatory management approach when implemented broadly, at the country level. Furthermore, implementation of this strategy in combination with border biosecurity and field monitoring may promote accurate prioritization, rapid species identification, and effective invasion pathway assessment.

Differences in MMP-2 Expression in High- and Low-Grade MPNST and its Correlation with Prognostic Factors

Malignant peripheral nerve sheath tumor (MPNST) is a soft tissue sarcoma, which is difficult to distinguish from other spindle cell sarcomas. MPNST is hostile, with a high recurrence, and tends to metastasize hematogenously, especially to the lungs. A phase of the metastasis is a degradation of the extracellular matrix, where Matrix Metalloproteinase (MMP) plays an essential role in this process. Gelatinase-type MMP, MMP-2 and MMP-9, can degrade basal membrane and fibrillar collagen to open the invasion pathway. MMP-2 can degrade more collagen and non-collagen extracellular matrix than MMP-9. Therefore, the study aimed to see the relationship between MMP-2 overexpression and histopathological malignancy grading and other clinical prognostic variables. The study was conducted by immunohistochemical staining of MMP-2 in 39 cases, consisting of 19 cases of low-grade MPNST and 20 cases of high-grade MPNST. Subsequently, an analysis of the relationship between MMP-2 overexpression and the malignancy grading and clinical variables was performed, such as age, sex, and tumor size and location. MMP-2 overexpression was seen in 19 (95%) cases of high grade and three (15.8%) cases of low-grade MPNST (p 0.000). The study also found a significant relationship between MMP-2 overexpression and histopathology grading, which may be helpful to define the prognosis.

Population genetics of the brown marmorated stink bug Halyomorpha halys in the early phase of invasion in South Tyrol (Northern Italy)

The brown marmorated stink bug Halyomorpha halys is one of the most harmful invasive species in the world. Native to East Asia, this insect was introduced into North America in the 1990s and into Europe in the 2000s where it subsequently established and spread across the continent. Previous population genetic studies determined the invasion pathways at continental and national levels. However, information on the dynamics on a small-scale is currently scarce. Here we study the genetic diversity and population dynamics of H. halys in South Tyrol, a region in Northern Italy, since its arrival to its widespread establishment over a period of four years. By haplotyping 162 individuals from ten populations (including six previously published individuals) we found a high haplotype diversity in most populations with an increasing diversity across the different years. Most haplotypes were previously found in other regions of Northern Italy, providing evidence for migration from neighboring regions. However, the presence of four previously undescribed haplotypes as well as a haplotype previously found exclusively in Greece highlights additional long-distance dispersal across the continent. Phylogenetic analysis of the haplotypes found in South Tyrol showed that the majority of haplotypes clustered with haplotypes predominantly found in Japan. This suggests a potential recent introduction of H. halys individuals from Japan into Europe, and thus an additional invasion pathway that was previously unidentified.

Australia’s wish list of exotic pets: biosecurity and conservation implications of desired alien and illegal pet species

Globalisation of the live pet trade facilitates major pathways for the transport and introduction of invasive alien species across longer distances and at higher frequencies than previously possible. Moreover, the unsustainable trade of species is a major driver for the over-exploitation of wild populations. Australia minimises the biosecurity and conservation risk of the international pet trade by implementing highly stringent regulations on the live import and keeping of alien pets beyond its international CITES obligations. However, the public desire to possess prohibited alien pets has never been quantified and represents a number of species that could be acquired illegally or legally under different future legislative conditions. As such, highly desirable species represent an ongoing conservation threat and biosecurity risk via the pet-release invasion pathway. We aimed to characterise the Australian desire for illegal alien pets and investigate potential sources of external information that can be utilised to predict future desire. Using public live import enquiry records from the Australian Commonwealth Department of Agriculture, Water and the Environment as a proxy for alien pet desire, we tested for differences in the proportion of species with threatened listings and records of invasions, after accounting for taxonomy. Additionally, we used a United States of America (U.S.) live imports dataset to infer pet demand in another Western market with less stringent regulations and determined whether species highly desired in Australia had higher U.S. trade demand than would be expected by chance. The Australian public desire for alien pets is heavily and significantly biased towards species threatened with extinction, species popular in the U.S. trade and species with a history of successful invasions. Not only does this indicate the potential impacts of pet desire on invasion risk and the conservation of threatened species, but we also highlight the potential role of the U.S. trade as an effective predictor for Australian desire. Our research emphasises the value of novel datasets in building predictive capacity for improved biosecurity awareness.

Development of Single Nucleotide Polymorphism (SNP) Markers for Analysis of Population Structure and Invasion Pathway in the Coconut Leaf Beetle Brontispa longissima (Gestro) Using Restriction Site-Associated DNA (RAD) Genotyping in Southern China

To determine population genomic structure through high-throughput sequencing techniques has revolutionized research on non-model organisms. The coconut leaf beetle, Brontispa longissima (Gestro), is a widely distributed pest in Southern China. Here, we used restriction site-associated DNA (RAD) genotyping to assess the invasion pathway by detecting and estimating the degree of genetic differentiation among 51 B. longissima accessions collected from Southern China. A total of 10,127 SNPs were obtained, the screened single nucleotide polymorphism (SNP) information was used to construct the phylogenetic tree, FST analysis, principal component analysis, and population structure analysis. Genetic structure analysis was used to infer the population structure; the result showed that all accessions were divided into Hainan population and non-Hainan population. The Hainan population remained stable, only the Sansha population differentiated, and the non-Hainan populations have gradually differentiated into smaller sub-populations. We concluded that there are two sources of invasion of B. longissima into mainland China: Taiwan and Hainan. With the increase of the invasion time, the Hainan population was relatively stable, and the Taiwan population was differentiated into three sub-populations. Based on the unrooted phylogenetic tree, we infer that Taiwan and Hainan are the two invasive base points. The Taiwan population invaded Fujian, Guangdong, and Guangxi, while the Hainan population invaded Yunnan and Sansha. Our results provide strong evidence for the utility of RAD sequencing (RAD-seq) in population genetics studies, and our generated SNP resource could provide a valuable tool for population genomics studies of B. longissima in the future.

New aliens in Australia: 18 years of vertebrate interceptions

ContextAustralia has a high diversity of endemic vertebrate fauna. Yet, transnational human activities continue to increase the rate of transportation, introduction and establishment of new alien vertebrates in Australia, to the detriment of environmental and socioeconomic services. Eradication of invasive vertebrates is often costly and without guarantee of success; therefore, methods for detecting, intercepting and preventing the transport of alien species earlier in the invasion pathway provide substantial benefit. AimTo anticipate emergent threats to Australian biosecurity posed by the transport and introduction of new alien vertebrates over time. MethodsWe collated vertebrate interception data from various mainland Australian State, Territory and Commonwealth government reporting agencies, including data from a previously published study, at both pre-border and post-border stages from 1999 to 2016. Using generalised linear and generalised additive modelling, we predicted trends in interception frequency using predictors such as vertebrate taxa, detection category and alien status. Key resultsInterception frequency increased over time for all vertebrate classes, for pre-border stowaways and for post-border captive and at-large interceptions, with no saturation in the accumulation of new species over time. Five species were responsible for almost half of all incidents, of which red-eared sliders (Trachemys scripta elegans), boa constrictors (Boa constrictor) and corn snakes (Pantherophis guttatus) are prominent in Australia’s illegal alien pet trade. Rose-ringed parakeets (Psittacula krameri) are prominent in the legal alien cage-bird trade, which remains poorly regulated. Asian common toads (Duttaphrynus melanostictus) were frequently detected as stowaways, and most stowaway incidents originated from Southeast Asia, particularly Indonesia, via shipping. Data deficiency for pre-border incidents increased rapidly in 2015 and 2016. ConclusionsAustralia is subject to a persistent and increasing risk of alien vertebrate introductions and incursions over time, owing partly to emergent trends in the alien pet trade as well as increased global trade and tourism. ImplicationsThe future of Australia’s biosecurity remains dependent on stringent border security to prevent the arrival of novel species, but our findings also highlight the importance of ongoing management and control of high-risk species already present, often illegally, within Australia.

Malaria transmission assisted by interaction between Plasmodium α-tubulin-1 and Anopheles FREP1 protein

ABSTRACTPassage of Plasmodium through a mosquito midgut is essential for malaria transmission. FREP1, a peritrophic matrix protein in a mosquito midgut, binds to the parasite and mediates Plasmodium infection in Anopheles. The FREP1-mediated Plasmodium invasion pathway is highly conserved across multiple species of Plasmodium and Anopheles. Through pulldown, nine P. berghei proteins were co-precipitated with FREP1-conjugated beads. After cloning these nine genes from P. berghei and expressing them in insect cells, six of them were confirmed to interact with recombinant FREP1 protein. Among them, α-tubulin-1 and heat shock protein 70 (Hsp70) were highly conserved in Plasmodium species with >95% identity. Thus, P. falciparum α-tubulin-1 and Hsp70 were cloned and expressed in E. coli to stimulate antibody (Ab) in mice. Our results showed that anti-serum against P. falciparum α-tubulin-1 significantly inhibited P. falciparum transmission to An. gambiae, while Ab against P. falciparum Hsp70 serum did not. The polyclonal Ab against human α-tubulin did not interfere formation of ookinetes, however, significantly reduced the number of P. falciparum oocysts in An. gambiae midguts. Moreover, fluorescence microscope assays showed that anti-α-tubulin Ab bound to impermeable Plasmodium ookinete apical invasive apparatus. Therefore, we propose that the interaction between Anopheles FREP1 protein and Plasmodium α-tubulin-1 directs the ookinete invasive apparatus towards midgut peritrophic matrix for the efficient passage of the parasite. Anopheles FREP1 and Plasmodium α-tubulin-1 are potential targets for blocking malaria transmission to the mosquito host.AUTHOR SUMMARYThe molecular mechanisms of malaria transmission to mosquito are not well-understood. FREP1 proteins in mosquito midget PM has been proved to mediate malaria transmission by binding to parasite ookinetes. Here we reported that Plasmodium parasite α-tubulin-1 is an FREP1 binding partner. We initially identified the α-tubulin-1 through the FREP1-pulldown assay; Then we cloned P. falciparum α-tubulin-1, and demonstrated that the insect cell expressed recombinant Plasmodium α-tubulin-1 bound to FREP1 in vitro; Next, mouse anti-serum against P. falciparum α-tubulin-1 was found to inhibit P. falciparum transmission to An. gambiae. P. falciparum α-tubulin-1 shares >84% identical amino acid sequence with human α-tubulin, purified Ab against human α-tubulin significantly inhibited malaria transmission. Anti-human α-tubulin Ab did not interfere the gametocyte-to-ookinetes conversion. Final, we found that anti-α-tubulin Ab bound to the apical end of impermeable ookinetes. Structurally, ookinete invasive apparatus locates at the apical opening. Therefore, we propose that the interaction between Anopheles midgut FREP1 protein and Plasmodium apical α-tubulin-1 directs the ookinete invasive apparatus towards midgut PM for the efficient parasite invasion.

Molecular identity of the non-indigenous Cassiopea sp. from Palermo Harbour (central Mediterranean Sea)

The upside-down jellyfish Cassiopea is a benthic scyphozoan, considered a non-indigenous invasive species in the Mediterranean, forming large blooms in eutrophic areas. Taxonomy of the genus Cassiopea is extremely difficult because morphological/meristic characters used are variable within the same species, overlapping among different species, and cryptic species have been identified by molecular markers; nine Cassiopea species are recognized on the basis of molecular study. Mediterranean records of Cassiopea have been ascribed to andromeda species on the basis of a hypothesized invasion pathway from the Suez Canal. In the current study, an analysis of the main morphological characters of the sampled Cassiopea jellyfish from Palermo (Tyrrhenian Sea) was carried out and subsequently, molecular analyses were performed by using COI barcode in order to identify the species. Molecular data were compared with published information in GenBank. Morphological characters were highly variable, but molecular analyses confirmed that Mediterranean Cassiopea specimens belong to andromeda species. Moreover, high values of sequence divergence were found between Mediterranean Cassiopea and the other C. andromeda from the Red Sea, Hawaii and Florida. These results lead to a discussion of possible explanations linked to life history features of the species. Two different explanations are proposed; the first is that Mediterranean C. andromeda, finding a suitable ecological niche good for colonization and proliferation, could have been isolated in Palermo Harbour. The second considers the possibility of multiple introduction events by human transport as demonstrated for other non-indigenous jellyfish; in this case Cassiopea genetic differences increased in the invaded area.