Generating an agricultural risk map based on limited ecological information: A case study using Sicyos angulatus

Undesirable dispersal via a river pathway of a single Argentine ant supercolony newly invading an inland urban area of Japan

Invasive ants pose a risk to human well-being and social/ecosystem stability. Linepithema humile Mayr is among the most damaging invasive ants worldwide. Most L. humile populations invade ports/wharfs isolated from surrounding landscapes, but unfortunately, a new population was discovered in an inland urban area (Nara Prefecture) of Japan in 2021. In this study, first, the supercolony type of the Nara L. humile population was identified via a hostility test, and then its distribution pattern was characterized. In aggression tests between L. humile from Nara and four supercolonies (haplotypes LH1, LH2, LH3, LH4), this ant showed extremely strong hostility against all supercolonies exept LH2, which was detected only in Japan in its introduced range. In Nara, L. humile was abundant in and around the urban river. Simulations revealed that using this environment for movement/dispersal increased the annual dispersal ability by 14 times compared with that achieved via ground (125 m), as mentioned in the literature. Therefore, river channels can serve as major pathways of long-distance dispersal for L. humile invading inland urban areas. Since applying chemical strategies around rivers is problematic, preventing L. humile from moving to rivers from initial invasion sites is crucial.

Prediction of the visit and occupy of the sika deer (Cervus nippon) during the summer season using a virtual ecological approach

Prediction of the spaces used by animals is an important component of wildlife management, but requires detailed information such as animal visit and occupy in a short span of the target species. Computational simulation is often employed as an effective and economical approach. In this study, the visit and occupy of sika deer (Cervus nippon) during the plant growing season were predicted using a virtual ecological approach. A virtual ecological model was established to predict the visit and occupy of sika deer based on the indices of their food resources. The simulation results were validated against data collected from a camera trapping system. The study was conducted from May to November in 2018 in the northern Kanto region of Japan. The predictive performance of the model using the kernel normalized difference vegetation index (kNDVI) was relatively high in the earlier season, whereas that of the model using landscape structure was relatively low. The predictive performance of the model using combination of the kNDVI and landscape structure was relatively high in the later season. Unfortunately, visit and occupy of sika deer could not predict in November. The use of both models, depending on the month, achieved the best performance to predict the movements of sika deer.

The complete chloroplast genome sequences of the Sicyos angulatus (Cucurbitaceae)

Sicyos angulatus (burcucumber) is an annual plant native to the north-eastern America. We investigated the genomic characteristics of the complete chloroplast (CP) genome in S. angulatus with a de novo strategy. The CP genome was 154,986 bp in length including 84 protein coding genes, 37 tRNA genes, and eight rRNA genes. It has large single-copy (LSC) (84,355 bp), small single-copy (SSC) (18,079 bp), and a pair of inverted repeats (IRs) (26,276 bp), which consists of typical quadripartite structure. A phylogenetic analysis of 64 CP genomes from Cucurbitaceae revealed that the Sicyos angulatus was separated from other species and clustered together with Sicyos edulis, which is congruent with previous studies. Infrafamilial classification system inferred from our data was also congruent with previous study based on CP DNA data.

Anti-hepatic steatosis activity of Sicyos angulatus extract in high-fat diet-fed mice and chemical profiling study using UHPLC-qTOF-MS/MS spectrometry

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Recently, the inhibitory effects of flavone glycosides isolated from Sicyos angulatus extract on hepatic lipid accumulation in vitro were demonstrated. However, the effects of S. angulatus extract and its major flavonoid glycoside on in vivo hepatic steatosis induced by a high-fat diet have not yet been established.

HYPOTHESIS/PURPOSE

The aim of this study was to investigate the effects of S. angulatus extract and its major flavonoid glycoside, kaempferol 3-O-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside, on hepatic steatosis in high-fat diet-fed mice, which serves as a model of NAFLD. In addition, attempts have been made to chemically profile the metabolites involved in the activity of the S. angulatus extract.

METHODS

C57BL/6 J mice were divided into vehicle, total extract of S. angulatus (SA; 50, 100 and 200 mg/kg) and major active component (20 mg/kg) groups. The mice were fed a high-fat diet (HFD) with or without S. angulatus extract or its major single compound for 10 weeks. Chemical identification was carried out using ultra-high-pressure liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-qTOF-MS/MS) and then quantified by HPLC-DAD.

RESULTS

Administration of S. angulatus extract significantly lowered plasma ALT and AST levels in HFD-fed mice compared to those of the vehicle group. The hepatic lipid content, as evidenced by oil-red O staining and quantification, was significantly lower in the S. angulatus-administered group, and the effect was dose dependent. These beneficial effects of S. angulatus extract were related to the decreased expression of hepatic genes involved in fatty acid (ACC1, FAS and SCD1) and triglyceride (DGAT) synthesis. The expression levels of two key transcription factors regulating lipogenesis, SREBP-1c and PPARγ, were significantly suppressed in the liver by administration of S. angulatus extract with HFD. Treatment of the HFD-fed mice with the major compound isolated from S. angulatus extract resulted in improved liver function along with an anti-steatotic effect similar to the results seen with S. angulatus extract. For the standardization of the S. angulatus extract, 23 compounds were identified based on MS/MS fragmentation and UV spectroscopy. Quantitative analysis of the major compound showed that the major component was present in 15.35 ± 0.01 mg/g of total extract.

CONCLUSION

These findings suggest that S. angulatus extract and its major component have the potential to improve liver function and hepatic steatosis in diet-induced obese mice.

Sicyos angulatus ameliorates acute liver injury by inhibiting oxidative stress via upregulation of anti-oxidant enzymes

OBJECTIVE

We aimed to investigate the effect of Sicyos angulatus (SA) ethanolic extracts as antioxidants and potential treatments for liver disease.

METHODS

To establish a mouse model of liver injury, C57BL/6 male mice were injected via the caudal vein with a single dose of concanavalin A (Con A, 15 mg kg^-1). SA extracts were administered once by oral gavage 30 min before Con A injection.

RESULTS

In vitro studies showed that SA decreased tert-butyl hydroperoxide (t-BHP)-induced reactive oxygen species (ROS) production. SA administration reduced plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, as well as hepatic ROS levels, in a dose-dependent manner. Moreover, SA increased the activities of the hepatic antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase in a dose-dependent manner. Furthermore, SA treatment reduced pro-apoptotic protein levels. Con A-mediated cytosolic release of Smac/DIABLO and apoptosis-inducing factor (AIF), which are markers of necrosis, were dramatically decreased in HepG2 cells treated with SA.

CONCLUSION

SA ameliorated liver injury and might be a good strategy for the treatment of liver injury.

Detecting crucial dispersal pathways using a virtual ecology approach: A case study of the mirid bug Stenotus rubrovittatus

Detecting dispersal pathways is important both for understanding species range expansion and for managing nuisance species. However, direct detection is difficult. Here, we propose detecting these crucial pathways using a virtual ecology approach, simulating species dynamics using models, and virtual observations. As a case study, we developed a dispersal model based on cellular automata for the pest insect Stenotus rubrovittatus and simulated its expansion. We tested models for species expansion based on four landscape parameters as candidate pathways; these are river density, road density, area of paddy fields, and area of abandoned farmland, and validated their accuracy. We found that both road density and abandoned area models had prediction accuracy. The simulation requires simple data only to have predictive power, allowing for fast modeling and swift establishment of management plans.