The House Crow (Corvus splendens): A Threat to New Zealand?

Transcriptome analysis of Corvus splendens reveals a repertoire of antimicrobial peptides

Multidrug resistance has become a global health problem associated with high morbidity and mortality. Antimicrobial peptides have been acknowledged as potential leads for prospective anti-infectives. Owing to their scavenging lifestyle, Corvus splendens is thought to have developed robust immunity to pathogens found in their diet, implying that they have evolved mechanisms to resist infection. In the current study, the transcriptome of C. splendens was sequenced, and de novo assembled to identify the presence of antimicrobial peptide genes. 72.09 million high-quality clean reads were obtained which were then de novo assembled into 3,43,503 transcripts and 74,958 unigenes. About 37,559 unigenes were successfully annotated using SwissProt, Pfam, GO, and KEGG databases. A search against APD3, CAMPR3 and LAMP databases identified 63 AMP candidates belonging to more than 20 diverse families and functional classes. mRNA of AvBD-2, AvBD-13 and CATH-2 were found to be differentially expressed between the three tested crows as well as among the tissues. We also characterized Corvus Cathelicidin 2 (CATH-2) to gain knowledge of its antimicrobial mechanisms. The CD spectroscopy of synthesized mature Corvus CATH-2 peptide displayed an amphipathic α-helical structure. Though the synthetic CATH-2 caused hemolysis of human RBC, it also exhibited antimicrobial activity against E. coli, S. aureus, and B. cereus. Docking simulation results revealed that this peptide could bind to the LPS binding site of MD-2, which may prevent LPS from entering the MD-2 binding pocket, and trigger TLR4 signaling pathway. The Corvus CATH-2 characterized in this study could aid in the development of novel therapeutics.

Spatial Distribution of the Mexican Daisy, Erigeron karvinskianus, in New Zealand under Climate Change

The invasive species Erigeron karvinskianus or Mexican daisy is considered a significant weed that impacts native forest restoration efforts in New Zealand. Mapping the potential distribution of this species under current and future predicted climatic conditions provides managers with relevant information for developing appropriate management strategies. Using occurrences available from global and local databases, spatial distribution characteristics were analyzed using geostatistical tools in ArcMap to characterize current distribution. Species distribution modeling (SDM) using Maxent was conducted to determine the potential spatial distribution of E. karvinskianus worldwide and in New Zealand with projections into future climate conditions. Potential habitat suitability under future climatic conditions were simulated using greenhouse gas emission trajectories under the Representative Concentration Pathway (RCP) models RCP2.6, RCP4.5, RCP6.0 and RCP8.5 for years 2050 and 2070. Occurrence data were processed to minimize redundancy and spatial autocorrelation; non-correlated environmental variables were determined to minimize bias and ensure robust models. Kernel density, hotspot and cluster analysis of outliers show that populated areas of Auckland, Wellington and Christchurch have significantly greater concentrations of E. karvinskianus. Species distribution modeling results find an increase in the expansion of range with higher RCP values, and plots of centroids show a southward movement of predicted range for the species.

Mapping the Potential Global Range of the Brown Marmorated Stink Bug, Halyomorpha halys, with Particular Reference to New Zealand

Originating from Asia, the brown marmorated stink bug (BMSB) is a significant pest of horticultural/agricultural crops, grapes, woody ornamental and herbaceous plants, and is also a nuisance to people, due to its overwintering behavior in human habitation. The global range of this pest is steadily increasing and previous predictions of environmental suitability have shown New Zealand to be highly suitable. Due to the economic value of horticultural and agricultural industries to the New Zealand economy, it is vital to understand the range of potential risk within the country. Global and New Zealand potential suitability for BMSB was modeled using three algorithms and the resulting predictions ensembled to predict the potential range under current climatic conditions and under trajectories of future low (Representative Concentration Pathways, RCP, 2.6) and high (RCP 8.5) greenhouse gas emissions for both 2050 and 2070. Under current conditions, models showed a high global suitability within latitudes 25°–50° N, southern South America, southeast and southwest regions of Australia and large areas of New Zealand. Modeling the effect of climate change on BMSB range in New Zealand resulted in a southerly range shift over time, particularly with high emissions trajectory. Currently, BMSB is not established in New Zealand and it is vital that this remains the case.