Bufo Melanostictus Research Articles

OCCURRENCE OF PATHOGENIC CHYTRID FUNGI BATRACHOCHYTRIUM SALAMANDRIVORANS AND BATRACHOCHYTRIUM DENDROBATIDIS IN THE HONG KONG NEWT (PARAMESOTRITON HONGKONGENSIS) AND OTHER WILD AND IMPORTED AMPHIBIANS IN A SUBTROPICAL ASIAN REGION.

One of the major threats for the massive loss in global amphibian diversity is chytridiomycosis, caused by chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Following its discovery in 2013, Bsal has emerged as a severe threat to the global survival of urodelans. In 2018, a study reported a high prevalence of Bsal (65.6%) in the Hong Kong newts (Paramesotriton hongkongensis, Near Threatened) of a southern China population adjacent to Hong Kong (HK). Uncertainty regarding the Bsal infection status of P. hongkongensis inhabiting HK raised deep concern over the risk of introducing Bsal from that population. We screened the skin swabs from wild individuals of P. hongkongensis, 15 sympatric amphibian species, and 16 imported amphibian species in HK for chytrids. We found that both Bsal and Bd occur in low prevalences in P. hongkongensis (Bsal 1.7%, 5/293; Bd 0.34%, 1/293), Hong Kong cascade frog, Amolops hongkongensis, family Ranidae (Bsal only, 5.26%, 1/19), and Asian common toad, Duttaphrynus melanostictus, family Bufonidae (Bsal only, 5.88%, 1/17), populations of HK, with infected individuals being asymptomatic, suggesting a potential role of these species as reservoirs of Bsal. Conversely, Bd, but not Bsal, was present on 13.2% (9/68) of imported amphibians, indicating a high chytrid introduction risk posed by international amphibian trade. Long-term surveillance of the presence of Bd and Bsal in wild and captive amphibians would be advisable, and we recommend that import and export of nonnative chytrid carriers should be prevented, especially to those regions with amphibian populations naïve to Bd and Bsal.

Diversity, Abundance, and Distribution of Anurans in Khyber Pakhtunkhwa, Pakistan

Aims: This paper presents a comprehensive study of the Anuran fauna of Khyber Pakhtunkhwa, Pakistan, which was conducted across nine districts. After the collection and identification of specimens from the study area, their diversity, relative abundance (RA), and distribution (C) were evaluated to understand their distribution patterns within Khyber Pakhtunkhwa.
 Place and Duration of Study: Anurans were collected from the districts of Peshawar, Dir, Bannu, Buner, Charsadda, Chitral, Karak, Lakki Marwat, and Haripur of Khyber Pakhtunkhwa from July to September 2021 and from April to June 2022.
 Study Design: Visual encounter surveys were conducted during different seasons, encompassing both daytime and nighttime observations near various water bodies such as water channels, small pools, and microhabitats suitable for the anurans. Emphasis was placed on the collection of specimens from diverse habitats. The collected specimens underwent thorough morphological and morphometric analyses to accurately identify the species.
 Methodology: In total, 190 specimens were collected and transported to the laboratory for identification. The collected specimens were euthanized, carefully arranged, and preserved in glass jars filled with a 10% formalin solution. Accurate species identification was achieved through the utilization of authentic literature, updated taxonomic keys, and observation and measurement of morphological and morphometric parameters.
 Results: The specimens that were examined and identified belonged to two families, Bufonidae and Dicroglossidae, and five genera. Two genera were observed in the Bufonidae family, Duttaphrynus and Bufotes. The Dicroglossidae family comprised three genera: Hoplobatrachus, Euphlyctis, and Allopaa. In the current study, seven different species were identified: Duttaphrynus stomaticus, Duttaphrynus melanostictus, Bufotes surdus from the Bufonidae family, and Hoplobatrachus tigerinus, Euphlyctis cyanophlyctis, Euphlyctis kalasgramensis, and Allopaa hazarensis from the Dicroglossidae family. Duttaphrynus stomaticus was the most abundant species found at all the study sites (C=88.8% and RA=44.2%), whereas Euphlyctis kalasgramensis and Allopaa hazarensis were sporadic (C=11.1% and RA=0.52%), and (C=11.1% and RA=2.10%), respectively. Furthermore, this research unveils the first-ever report of Euphlyctis kalasgramensis within Khyber Pakhtunkhwa, specifically in the Peshawar District, while Allopaa hazarensis was solely reported in the Dir district.
 Conclusion: The study found that Duttaphrynus stomaticus exhibited a vast distribution across all nine districts surveyed. Khyber Pakhtunkhwa, being an ecologically diverse area, holds diverse anuran fauna. Taxonomic revision of the anuran fauna using both classical and molecular approaches may yield several new taxa. This will further help in the study of biology and conservation as well as the ecological role of anurans. The current taxonomic work may require improvement.

Geographic Variation in Organ Size in a Toad (Duttaphrynus melanostictus).

Adaptive evolution is the process by which organisms change their morphological, physiological and biochemical characteristics to adapt to different environments during long-term natural selection. Especially, researching variation in organ size can provide important insights into morphological adaptation in amphibians. In this study, we comparatively studied differences in organ sizes (heart, lungs, liver, gallbladder, kidneys, spleen, digestive tract, testes and brain) among five geographical populations of the Asian common toad Duttaphrynus melanostictus. Our results revealed significant variations in the size of these nine specific organs among the populations. Notably, we observed a significant positive correlation between the relative size of the testes and latitude and/or altitude. However, no correlation was found between the relative size of the heart and the length of the digestive tract with altitude across populations, respectively, contradicting Hesse's rule and the digestion theory. These findings suggest that our study does not provide substantial theoretical support for the adaptive evolution of organ size in this particular toad species, but rather contributes to the understanding of the evolution and adaptations of species' different environmental conditions. Further research is warranted to delve deeper into the factors influencing organ size in amphibian populations.

Cath-DM-NT, a peptide derived from the skin of Duttaphrynus melanostictus, shows dual lectin-like and antioxidant activity

Chansu, a mixture extracted from Duttaphrynus melanostictus or Bufo gargarizans Cantor, is a traditional Chinese medicine with a broad range of medical applications. However, the peptides/proteins in it have not received adequate attention. Herein, a Cathelicidin-DM-derived peptide named Cath-DM-NT was identified from the skin of D. melanostictus. Previous studies have shown that Cathelicidin-DM has significant antibacterial activity, while Cath-DM-NT has no antibacterial activity. In this study, Cath-DM-NT is found to have lectin-like activity which can agglutinate erythrocytes and bacteria, and bind to lipopolysaccharide (LPS). In addition, Cath-DM-NT has antioxidant activity, which can scavenge 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and nitric oxide (NO) radicals and reduce Fe3+. Consistently, Cath-DM-NT can protect PC12 cells from H2O2-induced oxidative damage and carrageenan-induced paw edema, reduce malondialdehyde (MDA) and reactive oxygen species (ROS) accumulation, and restore superoxide dismutase (SOD) and glutathione (GSH) levels. Our study suggests that Cath-DM-NT can serve as a lead compound for the development of drugs with dual lectin and antioxidant effects.

Cinobufagin: a promising therapeutic agent for cancer.

Cinobufagin is a natural active ingredient isolated from the traditional Chinese medicine Venenum Bufonis (Chinese: Chansu), which is the dried secretion of the postauricular gland or skin gland of the Bufo gargarizans Cantor or Bufo melanostictus Schneider. There is increasing evidence indicating that cinobufagin plays an important role in the treatment of cancer. This article is to review and discuss the antitumor pharmacological effects and mechanisms of cinobufagin, along with a description of its toxicity and pharmacokinetics. The public databases including PubMed, China National Knowledge Infrastructure and Elsevier were referenced, and 'cinobufagin', 'Chansu', 'Venenum Bufonis', 'anticancer', 'cancer', 'carcinoma', and 'apoptosis' were used as keywords to summarize the comprehensive research and applications of cinobufagin published up to date. Cinobufagin can induce tumour cell apoptosis and cycle arrest, inhibit tumour cell proliferation, migration, invasion and autophagy, reduce angiogenesis and reverse tumour cell multidrug resistance, through triggering DNA damage and activating the mitochondrial pathway and the death receptor pathway. Cinobufagin has the potential to be further developed as a new drug against cancer.

Life History Traits and Longevity of the Invasive Asian Common Toad Duttaphrynus melanostictus (Schneider, 1799) in Madagascar

We analyzed the body length, age structure, and age at sexual maturity of the invasive Asian common toad Duttaphrynus melanostictus from different sites in Toamasina, east Madagascar. We used skeletochronology as a proxy for age estimation, while gonads were histologically analyzed to determine the age of sexual maturity. The analysis of pooled age data from three sites investigated in 2016 showed that both sexes were larger, although not older, than those of native populations. For the individuals from Madagascar, the males were significantly smaller and younger (mean ± SD, SVL: 71.4 ± 1.6 mm; age: 1.8 ± 0.7 years) than the females (SVL: 78.42 ± 1.9 mm; age: 2.7 ± 1.3 years), when the data were pooled, but when the data were analyzed separately for each of the three sites, similar results were obtained only for one site. The oldest recorded male and female were 3 and 6 years old, respectively. Gonadal histology showed that the males and females reach sexual maturity after the first and second years of age, respectively. Further studies are needed to understand if the larger size and faster growth rates observed in the invasive population of D. melanostictus in Madagascar are a consequence of more favorable environmental conditions with respect to the native range (e.g., the availability of larger trophic niches, a lack of competitors, and lower predatory pressure), and we suggest to extend the monitoring of these life history traits to understand how they might influence the invasion.

Monitoring Keanekaragaman dan Kemelimpahan Katak dan Kodok (Amphibia: Anura) di Sisi Timur Area Kampus UGM Yogyakarta

The diversity of frogs and toads in Universitas Gadjah Mada campus area has been studied by Prasintaningrum on the year 2018. The 2018 study found five different species of frogs and toads in the campus area. The diversity and abundance of frogs and toads species in the east side of campus area is monitored in this study. The purpose of this study is to compare the diversity and abundance also the distribution of frogs and toads in the east side of campus area between the year 2018 and 2020. This study conducted using visual encounter survey and time-constrained search as the sampling technique. From the monitoring result we concluded that the diversity and evenness of frogs and toads show reducing value in year 2020 compared to 2018. Duttaphrynus melanostictus species show increase in abundance, instead Kaloula baleata and Polypedates leucomystax show reduce in abundance in year 2020 compared to 2018. The relative distribution is changing in year 2020 compared to 2018.  Key words: Anura; monitoring; diversity; abundance; Universitas Gadjah Mada.

EFFECT OF VITAMIN A ON SKIN AND METAMORPHOSIS OF BUFO MELANOSTICTUS STAGE 23

Vitamin A has been found to affect differentiation of skin in the toad tadpoles and the effect is more severe on younger tadpoles as compared to the older ones. The tadpoles of stage 23 when treated with vitamin A, distinct effect was swelling of tadpoles particularly in the ventral region. Integument became transparent and the cellular organization of integument has disrupted severely and cells appear to be swollen mucoid type. Such condition is known as mucous metaplasia. Vitamin A treatment causes mucous mataplasia both in the dorsal and ventral region in this stage (stage 23) of tadpoles of Bufo melanostictus. Vitamin A induced mucous metaplasia is greater on the ventral region as compared to the dorsal region of the body. Vitamin A treatment has been found to inhibit differentiation of skin glands and metamorphosiis in tadpoles of stage 23. The characteristic swelling as a result of vitamin A treatment is in not found in the tadpoles of older stages. Keywords: Anuran, Dermis, Epidermis, Melanophores, Mucous metaplasia, Tadpoles.

Morphometrics, Habitat and Breeding Activity of Asian Common Toad, <i>Duttaphrynus melanostictus</i>, in Pakistan

The scientific data on ecology of amphibians from Pakistan are scarce. Asian Common Toad (Duttaphrynus melanostictus) is widely distributed in South Asia, and has been introduced outside its range causing severe ecological problems. We gathered data on morphometrics, habitat and breeding activity of the species in its western edge, North Punjab, Pakistan, of the range. The morphometric measurements of Asian Common Toad showed that the males were 49 ± 3.4 mm in snout vent length while the females were 58 ± 5.5 mm. Of the 13 measurements tested, the factor analysis produced five (head width, forelimb length, femur length, width of upper eyelid and foot length) significant measurements (r 0.80) for male while six (snout-vent length, head width, head length, greatest tympanum diameter, forelimb length, length of tarsus and foot) for female. The substrate of the habitat of Asian Common Toad was recorded as muddy to stony; water with neutral to slightly alkaline pH; dominated by herbs: Cannabis sativa, Parthenium hysterophorus; shrubs: Dodonaea viscosa, Lantana camara; grasses: Cynodon dactylon, Dactyloctenium aegyptium; and hydrophytes Alternanthera sessilis and Centella asiatica. The mean air and water temperature (day) during the breeding period were 27 – 30.5 and 25 – 28.5°C, respectively. The toad species laid eggs in small sized pools with lentic to slow-moving water with the mean depth of 32 – 64 cm. The males were more abundant than females (2.14♂:1♀) at the breeding sites. The advertisement call was of 9.3 ± 0.80 sec duration with a single note and 49.5 ± 6.5 nodes, –7.45 ± 0.95 average amplitude, 776 ± 51.8 Hz minimum frequency and 7011 ± 1680 Hz maximum frequency.

Spatial ecology of the invasive Asian common toad in Madagascar and its implications for invasion dynamics

Invasion dynamics are determined, among other aspects, by the spatial behaviour of invasive populations. The invasive toad Duttaphrynus melanostictus is spreading inland from the eastern coast of Madagascar, causing considerable ecological impacts. Understanding the basic factors determining the spread dynamics can inform management strategies and provide insights into spatial evolutionary processes. We radio-tracked 91 adult toads in three localities along the invasion gradient to determine whether spatial sorting of dispersive phenotypes is occurring, and investigate intrinsic and extrinsic determinants of spatial behaviour. Overall, toads in our study appeared as habitat generalists, and their sheltering behaviour was tied to water proximity, with toads changing shelter more frequently closer to waterbodies. Toads showed low displacement rates (mean = 4.12 m/day) and quite a philopatric behaviour but were able to perform daily movements of over 50 m. We did not detect any spatial sorting of dispersal-relevant traits nor sex- or size-biased dispersal. Our results suggest that toads are more likely to expand their range during the wet season, and that the range expansion is probably dominated by short-distance dispersal at this stage of the invasion, although a future increase in invasion speed is expected, due to the capacity for long-distance movements of this species.

Bufalin-Mediated Regulation of Cell Signaling Pathways in Different Cancers: Spotlight on JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, and Non-Coding RNAs

The renaissance of research into natural products has unequivocally and paradigmatically shifted our knowledge about the significant role of natural products in cancer chemoprevention. Bufalin is a pharmacologically active molecule isolated from the skin of the toad Bufo gargarizans or Bufo melanostictus. Bufalin has characteristically unique properties to regulate multiple molecular targets and can be used to harness multi-targeted therapeutic regimes against different cancers. There is burgeoning evidence related to functional roles of signaling cascades in carcinogenesis and metastasis. Bufalin has been reported to regulate pleiotropically a myriad of signal transduction cascades in various cancers. Importantly, bufalin mechanistically regulated JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, EGFR, and c-MET pathways. Furthermore, bufalin-mediated modulation of non-coding RNAs in different cancers has also started to gain tremendous momentum. Similarly, bufalin-mediated targeting of tumor microenvironments and tumor macrophages is an area of exciting research and we have only started to scratch the surface of the complicated nature of molecular oncology. Cell culture studies and animal models provide proof-of-concept for the impetus role of bufalin in the inhibition of carcinogenesis and metastasis. Bufalin-related clinical studies are insufficient and interdisciplinary researchers require detailed analysis of the existing knowledge gaps.

Amphibian diversity of wetlands of Rewa district of Madhya Pradesh with a note on the morphometric characters of Duttaphrynus melanostictus

Rewa district is gifted with lot of wetlands significantly Bichhiya, Bihar and Tamas wetland is home of 12 amphibian species under 5 family. Of which 1 species belonged to family Bufonid, 2 species to family microhylid, 1 species to family Rhacophorid, 6 species to family Dicroglossidae and 2 species to Ranidae. Morphometric study was carried out for Duttaphrynus melanotic. Significant variation was observed in the morphometric characteristics of D. melanotic with its Lectotype. Supratympanic fold was found to be present and parietal ridge is absent in case of specimens of Rewa, while vice versa in Lectotype. Webbing formula found to be I0-1II0-1½III1-3½IV3½-1½ in case of lectotype, where as in the specimens from Rewa it is I1-1½ II1½-2½ III1½-3½ IV3½-1½.

Fight, flight or bright(en)

When you think of colour-changing animals, what comes to mind? A slow-moving chameleon barely distinguishable from its spot in a tree? Or maybe an octopus camouflaging itself on the ocean floor? What about hundreds of bright yellow male Asian common toads (Duttaphrynus melanostictus) gathering to fight each other for the company of their somewhat drab, brown-coloured mates? During monsoon rains, the toads gather in groups of over 200 individuals at breeding sites throughout South and Southeast Asia. Before congregating, the male toads swiftly change colour to a conspicuous yellow, signalling to other males that they are ready to fight – and to distinguish themselves to potential female mates. Unsurprisingly, hormones associated with the ‘fight or flight’ response are high during these ‘explosive breeding’ events thanks to the stressful monsoon rains that coincide with the mating season and fighting for partners. Could these hormones have something to do with the toads’ striking colour change? Susanne Stückler and Doris Preininger from the University of Vienna, Austria, and their colleague Matthew Fuxjager from Brown University, USA, decided to investigate.The trio turned to a group of toads housed in Vienna Zoo, Austria, to see which hormones were responsible for the colour change. First, they measured the colour of the toads’ backs – specifically, the hue (what we normally think of when we describe colour), brightness (lightness or darkness) and chroma (colour saturation). Having established the toads’ baseline colour, the researchers tested whether a dose of the reproductive hormone human chorionic gonadotropin (hCG) could trick the toads into thinking that it was breeding season and trigger a rapid colour change. Surprisingly, the toads did not turn bright yellow when they experienced an increase in their reproductive hormone levels. If reproductive hormones such as hCG aren't triggering a change in colour, could the hormones associated with a stressful experience be driving the colourful transformation instead?To test this, the scientists gave the toads one of the stress hormones, either adrenaline (epinephrine) or noradrenaline (norepinephrine), and again recorded the toads’ hue, brightness and colour saturation. With either stress hormone, the toads became brighter and their shade of yellow became more saturated. Interestingly, for these toads, only a grape-sized patch of skin changed colour (about half the size of the body), and a few did not change colour at all.To make sure any colour changes the scientists saw in these treatments could actually be seen by potential mates (or sparring partners), Stückler and colleagues also calculated how noticeable the colour changes would be to the eyes of a toad. Using the colour perception data of a close relative, the common toad (Bufo bufo), the scientists were able to estimate just how different this stress-induced yellow would be from the typical brown colour of females or males – and indeed, the yellow stood out! The scientists suggest that to trigger the whole-body colour change, perhaps there are other hormones at play that they haven't tested yet. Or perhaps physical signals such as monsoon rains and social cues such as the company of other toads work together with stress hormones during explosive breeding events in the wild.This is the first time that stress hormones alone have been shown to cause animals to change colour rapidly without the help of other hormones that signal breeding. For Asian common toads, being a brighter, flashier yellow might make them more successful during these explosive breeding events, so it would make sense that they have embraced another means to quickly change colour. So, next time you think of colour-changing animals, perhaps you'll picture the bright yellow Asian common toad – and how their ‘fight or flight’ hormones have now been adopted for flashiness.

An Asian Common Toad (duttaphrynus melanostictus, Schneider, 1799) (Anura: bufonidae) feeding on the scorpion Janalychas sp. in India.

The first record of an Asian common Toad (duttaphrynus melanostictus, Schneider, 1799) (Anura: bufonidae) praying on the scorpion Janalychas sp, from a ‘Padmashree Dr. D.Y.Patil Technical campus’ Talsande, Tal.-Hatkanangale, Dist.- Kolhapur, Maharashtra, India. This is first record of an Asian Toad.

Ecotoxicity risk assessment of copper oxide nanoparticles in Duttaphrynus melanostictus tadpoles

In recent years, copper oxide nanoparticles (CONPs) have gained considerable importance in ecotoxicology studies. CONP ecotoxicity studies on amphibians are limited, particularly on Duttaphrynus melanostictus (D. melanostictus) tadpoles, and most CONP ecotoxicity studies have shown developmental effects on amphibians. Therefore, the present study aimed to determine the ecotoxicity of CONPs in D. melanostictus tadpoles by assessing multi-biomarkers including bioaccumulation, antioxidants, biochemical, haematological, immunological and oxidative stress biomarkers. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to characterize the morphology and physicochemical properties of CONPs. After 30 d of the experiment, blood and organs were collected to measure the levels of multiple biomarkers. The dissolution rate of copper ions in exposed media was observed in all studied groups. According to the results, significant (p < 0.05) increase in copper ion bioaccumulation (blood, liver and kidney), oxidative stress and biochemical biomarkers in the blood serum of CONPs exposed tadpoles compared to control tadpoles, which was accompanied by significant variations in morphological and haematological parameters. In contrast to the untreated tadpoles, the CONPs-exposed tadpoles showed statistically significant (p < 0.05) decreases in antioxidants and immunological indices of blood serum. Based on our results, we concluded that the ecotoxicity of CONPs is due to the production of reactive oxygen species (ROS), which can cause oxidative stress in tadpoles, resulting in impairments. According to our knowledge, the present study was the first to use a multi-biomarker ecotoxicity approach on D. melanostictus tadpoles that could be used as an ecological bioindicator to assess aquatic toxicity.

The toad less travelled: comparing life histories, ecological niches, and potential habitat of Asian black-spined toads and cane toads

Context Invasive vertebrates have significant negative impacts on biodiversity and agricultural production worldwide. Increased connectivity among countries, through trade and tourism, is escalating the rate of introductions of vertebrate species, particularly herpetofauna, across international borders. In Australia, Asian black-spined toads (ABSTs; Duttaphrynus melanostictus) are one of the species most intercepted at borders. They are considered a biosecurity risk because of the potential for negative environmental impacts, similar to those caused by cane toads (Rhinella marina). Aims We aimed to compare ABSTs with cane toads to investigate potential impacts and distribution of ABSTs in the Australian context. We also aimed to identify knowledge gaps regarding ABST biology and the potential role of cane toads in an ABST invasion in Australia. Methods We undertook a literature review to obtain published data to compare the life history characteristics of ABSTs and cane toads. We also modelled climatic niche overlap and compared suitable habitat for both species in Australia. Key results Our results show ABSTs and cane toads have broadly similar reproductive life histories and feeding niches. In particular, similarities include large clutch sizes, preferred oviposition sites, and diet at tadpole and adult life stages. In Australia, the species share suitable potential habitat, particularly in North Queensland, where the majority of ABST incursions have occurred. The species differ in size, call characteristics, clutch size relative to body size, and egg development rate, although the environment also influences these traits. We identify gaps in our knowledge of ABST spatial ecology, thermal tolerances, water reliance, and habitat. Conclusions ABSTs pose a significant biosecurity threat to Australia. Similarities in life history to cane toads means they may have similar impacts, but may have a more limited distribution in Australia. Invasion of Australia by ABSTs would likely result in interactions with cane toads, but it is not possible to accurately determine the outcomes of those interactions without further investigation. Implications Addressing knowledge gaps and quantitatively determining the potential for competition between ABSTs and cane toads will assist surveillance and response planning for ABST incursions in Australia.

Morphological and Ecological Correlates of Anuran Tadpoles in Scrub and Subtropical Pine Forests

We recorded tadpoles of eight anuran species from subtropical scrub and pine forests (District Rawalpindi and Islamabad Capital Territory, Pakistan). These include Duttaphrynus melanostictus, Duttaphrynus stomaticus, Microhyla nilphamariensis, Euphlyctis spp., Minervarya spp., Allopaa hazarensis, Nanorana vicina, and Hoplobatrachus tigerinus. Our results showed that the forest type featuring scrub vegetation, low elevation and warmer climate (day air temperature 30°C, day water temperature 28°C) had more species richness (six of the eight recorded species) while the subtropical pine forest featuring relatively low air (16°C) and water (14°C) temperatures and higher elevation had relatively higher anuran endemism. The Indus Valley Toad is an abundant species throughout scrub forest. Changes in climate resulting in increased temperatures in pine forests could negatively impact endemic species by encouraging the spread of species adapted for warmer temperatures.

Using public surveys to rapidly profile biological invasions in hard‐to‐monitor areas

AbstractUnderstanding the impact and dynamics of invasive alien species (IAS) is essential for tailoring appropriate management plans. This information can be difficult to obtain in the short term, and intrinsic difficulties of monitoring hard‐to‐reach areas may hamper prompt estimation of IAS distributions. Using the case of the invasive Asian common toad (Duttaphrynus melanostictus) in Madagascar, we show how public surveys coupled with a multi‐analytical approach can promptly provide accurate information on invasion dynamics and impacts. On the basis of key‐informant responses, we built polynomial regressions to investigate the spatiotemporal invasion patterns, false‐positive occupancy models to estimate species occupancy, and mixed‐effect models to evaluate the public perception and attitudes. The invasion followed a linear expansion of approx. 2 km year−1, with human‐mediated dispersal facilitating the spread of the species. Toad occupancy decreased towards the invasion front and increased in the southern portion of its range. Negative perception decreased in urban areas, where people were less concerned by toad impacts on ecosystems, and in recently invaded localities, suggesting density‐ or time‐dependent effects. We also identified 12 potential impacts, with “loss of domestic apiaries”, “poisoning of poultry” and “decline of snakes” standing out for prevalence and potential severity. Our results bring important insights into the invasion dynamics and the human‐toad interactions in Madagascar, highlighting the versatility of public surveys to obtain essential information for invasion science and management, which can be especially useful in hard‐to‐monitor regions of the world with a low in‐country capacity to counter invasive species.

Uncovering the Mechanisms of Active Components from Toad Venom against Hepatocellular Carcinoma Using Untargeted Metabolomics.

Toad venom, a dried product of secretion from Bufo bufo gargarizans Cantor or Bufo melanostictus Schneider, has had the therapeutic effects of hepatocellular carcinoma confirmed. Bufalin and cinobufagin were considered as the two most representative antitumor active components in toad venom. However, the underlying mechanisms of this antitumor effect have not been fully implemented, especially the changes in endogenous small molecules after treatment. Therefore, this study was designed to explore the intrinsic mechanism on hepatocellular carcinoma after the cotreatment of bufalin and cinobufagin based on untargeted tumor metabolomics. Ultraperformance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) was performed to identify the absorbed components of toad venom in rat plasma. In vitro experiments were determined to evaluate the therapeutic effects of bufalin and cinobufagin and screen the optimal ratio between them. An in vivo HepG2 tumor-bearing nude mice model was established, and a series of pharmacodynamic indicators were determined, including the body weight of mice, tumor volume, tumor weight, and histopathological examination of tumor. Further, the entire metabolic alterations in tumor after treating with bufalin and cinobufagin were also profiled by UHPLC-MS/MS. Twenty-seven active components from toad venom were absorbed in rat plasma. We found that the cotreatment of bufalin and cinobufagin exerted significant antitumor effects both in vitro and in vivo, which were reflected in inhibiting proliferation and inducing apoptosis of HepG2 cells and thereby causing cell necrosis. After cotherapy of bufalin and cinobufagin for twenty days, compared with the normal group, fifty-six endogenous metabolites were obviously changed on HepG2 tumor-bearing nude mice. Meanwhile, the abundance of α-linolenic acid and phenethylamine after the bufalin and cinobufagin intervention was significantly upregulated, which involved phenylalanine metabolism and α-linolenic acid metabolism. Furthermore, we noticed that amino acid metabolites were also altered in HepG2 tumor after drug intervention, such as norvaline and Leu-Ala. Taken together, the cotreatment of bufalin and cinobufagin has significant antitumor effects on HepG2 tumor-bearing nude mice. Our work demonstrated that the in-depth mechanism of antitumor activity was mainly through the regulation of phenylalanine metabolism and α-Linolenic acid metabolism.

Wound healing mechanism of antimicrobial peptide cathelicidin-DM.

Background and Purpose: Chronic wound infections and the development of antibiotic resistance are serious clinical problems that affect millions of people worldwide. Cathelicidin-DM, an antimicrobial peptide from Duttaphrynus melanostictus, has powerful antimicrobial activity and wound healing efficacy. So, it could be a potential candidate to address this problem. In this paper, we investigate the wound healing mechanism of cathelicidin-DM to establish a basis for preclinical studies of the drug. Experimental Approach: The effects of cathelicidin-DM on cell proliferation and migration, cytokines, and mitogen-activated protein kinase (MAPK) signaling pathways were examined. Then mice whole skin wound model was constructed to evaluate the wound healing activity of cathelicidin-DM, and further histological changes in the wounds were assessed by hematoxylin-eosin staining (H&E) and immunohistochemical assays. Key Results: Cathelicidin-DM promotes the proliferation of HaCaT, HSF, and HUVEC cells in a concentration-dependent manner and the migration of HSF, HUVEC, and RAW.264.7 cells. Moreover,cathelicidin-DM can involve in wound healing through activation of the MAPK signaling pathway by upregulating phosphorylation of ERK, JNK, and P38. However, cathelicidin-DM didn't affect the secretion of IL-6 and TNF-α. At the animal level, cathelicidin-DM accelerated skin wound healing and early debridement in mice as well as promoted re-epithelialization and granulation tissue formation, α-SMA expression, and collagen I deposition in mice. Conclusion and Implications: Our data suggest that cathelicidin-DM can be engaged in the healing of infected and non-infected wounds through multiple pathways, providing a new strategy for the treatment of infected chronic wounds.