scholarly journals Natural history and conservation of the rediscovered Hula painted frog, Latonia nigriventer

2017 ◽  
Vol 86 (1) ◽  
pp. 11-37 ◽  
Author(s):  
R.G. Bina Perl ◽  
Sarig Gafny ◽  
Yoram Malka ◽  
Sharon Renan ◽  
Douglas C. Woodhams ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Natural History ◽  
Batrachochytrium Dendrobatidis ◽  
Sister Group ◽  
Amphibian Declines ◽  
Biological Information ◽  
Conservation Strategies ◽  
Future Research ◽  
Amphibian Chytrid Fungus ◽  
Pelophylax Bedriagae

Dramatic global amphibian declines have recently led to an increased concern for many species of this animal class. The enigmatic Hula painted frog (Latonia nigriventer), the first amphibian to be declared extinct but unexpectedly rediscovered in 2011, has remained one of the rarest and most poorly understood amphibians worldwide. Gathering basic biological information on this species, along with an understanding of its disease-related threats remains fundamental for developing risk assessments and conservation strategies. Our surveys in recent years confirmed that L. nigriventer is a localised species with elusive habits. The species appears to follow an opportunistic breeding phenology and has a tadpole morphology similar to its well-studied sister group Discoglossus. However, the adults’ extended annual presence in the aquatic habitat is a major difference from species of Discoglossus. We detected the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), in northern Israel and on Hula painted frogs but did not observe any signs of chytridiomycosis in this species. Our preliminary data on aspects of the innate immunity of L. nigriventer suggest that the skin mucosome of this species contains antimicrobial peptides and a bacterial community differing from other syntopic frogs (Pelophylax bedriagae). The combined knowledge of both natural history and innate immunity of L. nigriventer provides valuable insights to direct future research and conservation management of this critically endangered frog species.

Detection of ranavirus in endemic and threatened amphibian populations of the Australian Wet Tropics Region

2020 ◽  
Vol 26 (1) ◽  
pp. 93
Author(s):  
Felicity J. Wynne
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Quantitative Polymerase Chain Reaction ◽  
Amphibian Declines ◽  
Chain Reaction ◽  
Individual Level ◽  
Frog Species ◽  
Wet Tropics ◽  
Polymerase Chain ◽  
The Individual ◽  
Amphibian Chytrid Fungus

The amphibian chytrid fungus (Batrachochytrium dendrobatidis) has driven severe amphibian declines in the Australian tropics. These declines have resulted in species extirpations and extinctions, with many surviving in small, highly threatened populations. Despite the fragility of remaining populations, another group of lethal pathogens, ranaviruses, have rarely been investigated among native amphibians. Ranaviruses have previously been associated with fish, reptile and amphibian mortality events in Australia, yet remain poorly understood here, especially among amphibian hosts. Here, quantitative polymerase chain reaction assays were used to detect ranavirus presence from eight of 17 tested sites containing populations of endangered and critically endangered Australian frog species. Although present in these populations, ranavirus seems to be at the lower bounds of detectability of the assay, which makes firm diagnosis at the individual level unreliable. Repeated (n=14) detections of this pathogen, however, are highly indicative of its presence at each area where it was detected. Therefore, these populations are likely often exposed to ranavirus. The results of this study are not characteristic of populations experiencing rapid disease-associated die-offs or declines, but further investigations should be undertaken to examine the potential drivers of these pathogens to predict future emergence and potential threats to endangered Australian amphibians.

scholarly journals Modelling the amphibian chytrid fungus spread by connectivity analysis: towards a national monitoring network in Italy

2021 ◽  
Author(s):  
Andrea Costa ◽  
Lorenzo Dondero ◽  
Giorgia Allaria ◽  
Bryan Nelson Morales Sanchez ◽  
Giacomo Rosa ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
National Level ◽  
Monitoring Network ◽  
Electric Circuit ◽  
Population Declines ◽  
Climate Data ◽  
Landscape Permeability ◽  
National Monitoring ◽  
Climatic Scenarios ◽  
Amphibian Chytrid Fungus

AbstractThe emerging amphibian disease, Batrachochytrium dendrobatidis (Bd), is driving population declines worldwide and even species extinctions in Australia, South and Central America. In order to mitigate effects of Bd on amphibian populations, high-exposed areas should be identified at the local scale and effective conservation measures should be planned at the national level. This assessment is actually lacking in the Mediterranean basin, and in particular in Italy, one of the most relevant amphibian diversity hotspots in the entire region. In this study, we reviewed the available information on Bd in Italy, and conducted a 5-year molecular screening on 1274 individual skin swabs belonging to 18 species. Overall, we found presence of Bd in 13 species and in a total of 56 known occurrence locations for peninsular Italy and Sardinia. We used these occurrence locations and climate data to model habitat suitability of Bd for current and future climatic scenarios. We then employed electric circuit theory to model landscape permeability to the diffusion of Bd, using a resistance map. With this procedure, we were able to model, for the first time, the diffusion pathways of Bd at the landscape scale, characterising the main future pathways towards areas with a high probability of Bd occurrence. Thus, we identified six national protected areas that will become pivotal for a nationally-based strategic plan in order to monitor, mitigate and possibly contrast Bd diffusion in Italy.

scholarly journals Is overwintering mortality driving enigmatic declines? Evaluating the impacts of trematodes and the amphibian chytrid fungus on an anuran from hatching through overwintering

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262561
Author(s):  
Olivia Wetsch ◽  
Miranda Strasburg ◽  
Jessica McQuigg ◽  
Michelle D. Boone
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Species Conservation ◽  
Emerging Infectious Diseases ◽  
The Novel ◽  
Chytrid Fungus ◽  
Growth And Survival ◽  
Critical Life Events ◽  
Overwintering Mortality ◽  
Amphibian Chytrid Fungus

Emerging infectious diseases are increasing globally and are an additional challenge to species dealing with native parasites and pathogens. Therefore, understanding the combined effects of infectious agents on hosts is important for species’ conservation and population management. Amphibians are hosts to many parasites and pathogens, including endemic trematode flatworms (e.g., Echinostoma spp.) and the novel pathogenic amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Our study examined how exposure to trematodes during larval development influenced the consequences of Bd pathogen exposure through critical life events. We found that prior exposure to trematode parasites negatively impacted metamorphosis but did not influence the effect of Bd infection on terrestrial growth and survival. Bd infection alone, however, resulted in significant mortality during overwintering—an annual occurrence for most temperate amphibians. The results of our study indicated overwintering mortality from Bd could provide an explanation for enigmatic declines and highlights the importance of examining the long-term consequences of novel parasite exposure.

scholarly journals Fungal infection, decline and persistence in the only obligate troglodytic Neotropical salamander

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Sampling Technique ◽  
Sympatric Species ◽  
Amphibian Declines ◽  
Small Range ◽  
Museum Specimens ◽  
Amphibian Species ◽  
Extant Population ◽  
Epidemic Wave

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

scholarly journals Improving the understanding of how patients with non-dystrophic myotonia are selected for myotonia treatment with mexiletine (NaMuscla): outcomes of treatment impact using a European Delphi panel

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ann-Marie Chapman ◽  
Marieke Schurer ◽  
Laure Weijers ◽  
Amer Omar ◽  
Hiba Lee ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Natural History ◽  
Negative Impact ◽  
Phase Iii ◽  
Future Research ◽  
Delphi Panel ◽  
Economic Modelling ◽  
Patient Access ◽  
History Of

Abstract Background Non-dystrophic myotonias (NDMs) comprise muscle chloride and sodium channelopathies due to genetic defects of the CLCN1- and SCN4A-channels. No licensed antimyotonic treatment has been available until approval of mexiletine (NaMuscla®) for adult patients by the EMA in December 2018. This Delphi panel aimed to understand how outcomes of the pivotal phase III Mexiletine study (MYOMEX) translate to real world practice and investigate health resource use, quality of life and the natural history of NDM to support economic modelling and facilitate patient access. Methods Nine clinical experts in treating NDM took part in a two-round Delphi panel. Their knowledge of NDM and previous use of mexiletine as an off-label treatment prior to NaMuscla’s approval ensured they could provide both qualitative context and quantitative estimates to support economic modelling comparing mexiletine (NaMuscla) to best supportive care. Consensus in four key areas was sought: healthcare resource utilization (HRU), treatment with mexiletine (NaMuscla), patient quality of life (QoL), and the natural history of disease. Concept questions were also asked, considering perceptions on the feasibility of mapping the validated Individualized Neuromuscular Quality of Life (INQoL) instrument to the generic EQ-5D™, and the potential impact on caregiver QoL. Results Consensus was achieved for key questions including the average long-term dosage of mexiletine (NaMuscla) in practice, the criteria for eligibility of myotonia treatment, the clinical importance of QoL outcomes in MYOMEX, the higher proportion of patients with increased QoL, and the reduction in the need for mental health resources for patients receiving mexiletine (NaMuscla). While consensus was not achieved for other questions, the results demonstrated that most experts felt mexiletine (NaMuscla) reduced the need for HRU and was expected to improve QoL. The QoL mapping exercise suggested that it is feasible to map domains of INQoL to EQ-5D. Points of interest for future research were identified, including that mexiletine (NaMuscla) may slow the annual decrease in QoL of patients over their lifetime, and a significant negative impact on QoL for some caregivers. Conclusions This project successfully provided data from an informed group of clinical experts, complementing the currently available clinical trial data for mexiletine (NaMuscla) to support patient access decisions.

Non-detection of mycoviruses in amphibian chytrid fungus (Batrachochytrium dendrobatidis) from Australia

2021 ◽  
Author(s):  
Rebecca J. Webb ◽  
Alexandra A. Roberts ◽  
Stephen Wylie ◽  
Tiffany Kosch ◽  
Luís Felipe Toledo ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Chytrid Fungus ◽  
Amphibian Chytrid Fungus

Data Mining in Gene Expression Analysis

2008 ◽  
pp. 1643-1673
Author(s):  
Jilin Han ◽  
Le Gruenwald ◽  
Tyrrell Conway
Keyword(s):  
Gene Expression ◽  
Data Mining ◽  
Biological Information ◽  
Future Research ◽  
Gene Expression Data Analysis ◽  
Experimental Conditions ◽  
Single Experiment ◽  
Important Approach ◽  
Future Research Directions ◽  
Gene Expression Levels

The study of gene expression levels under defined experimental conditions is an important approach to understand how a living cell works. High-throughput microarray technology is a very powerful tool for simultaneously studying thousands of genes in a single experiment. This revolutionary technology results in an extensive amount of data, which raises an important question: how to extract meaningful biological information from these data? In this chapter, we survey data mining techniques that have been used for clustering, classification and association rules for gene expression data analysis. In addition, we provide a comprehensive list of currently available commercial and academic data mining software together with their features. Lastly, we suggest future research directions.

The natural history of defences

2021 ◽  
pp. 51-108
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Innate Immunity ◽  
Natural History ◽  
Adaptive Immunity ◽  
Immune Memory ◽  
History Of ◽  
Molecular Backbone ◽  
Somatic Diversification ◽  
Signalling Compounds ◽  
Immune Defences ◽  
Signalling Cascade

Hosts can avoid infections by behavioural changes and by body walls. After infection, hosts can change their behaviours to reduce the effects of parasitism. Immune defences have different arms (humoral or cellular), and organization (innate, adaptive). Innate immunity consists of a collection of different systems that are evolutionarily very old. Adaptive immunity, based on expansion of specific lymphocytes, evolved in the higher vertebrates. Immune defences are regulated tightly and based on receptors that can recognize parasites (or their activity). This triggers a complex signalling cascade that results in the production of further signalling compounds and effectors. Important protein families, e.g. the immunoglobulins, form the molecular backbone. A key to efficient defences is the diversification of receptors, such as the highly evolved somatic diversification processes of advanced adaptive immunity. The microbiota adds to defences in many ways. Immune memory and priming occur throughout the tree of life.

scholarly journals Towards a phylogeny of the Metazoa: evaluating alternative phylogenetic positions of Platyhelminthes, Nemertea, and Gnathostomulida, with a critical reappraisal of cladistic characters

2004 ◽  
Vol 73 (1-2) ◽  
pp. 3-163 ◽  
Author(s):  
Ronald A. Jenner
Keyword(s):  
Sister Group ◽  
Morphological Characters ◽  
Total Evidence ◽  
Morphological Data ◽  
Future Research ◽  
Sister Group Relationship ◽  
Cladistic Analyses ◽  
Phylogenetic Hypotheses ◽  
Data Matrices

This paper critically assesses all morphological cladistic analyses of the Metazoa that were published during the last one and a half decades. Molecular and total evidence analyses are also critically reviewed. This study focuses on evaluating alternative phylogenetic positions of the ‘acoelomate’ worms: Platyhelminthes, Nemertea, and Gnathostomulida. This paper consists of two parts. In Part I, all recently proposed sister group hypotheses and the supporting synapomorphies for these phyla are evaluated. Discrepancies in the treatment of corresponding characters in different cladistic analyses are identified, and where possible, resolved. In Part II, the overall phylogenetic significance across the Metazoa of all characters relevant for placing the ‘acoelomate’ worms is examined. The coding and scoring of these characters for other phyla are evaluated, and uncertainties in our understanding are pointed out in order to guide future research. The characters discussed in this paper are broadly categorized as follows: epidermis and cuticle, reproduction and sexual condition, development, larval forms, coeloms and mesoderm source, nervous system and sensory organs, nephridia, musculature, digestive system, and miscellaneous characters. Competing phylogenetic hypotheses are compared in terms of several criteria: 1) taxon sampling and the fulfillment of domain of definition for each character; 2) character sampling; 3) character coding; 4) character scoring and quality of primary homology; 5) quality of the proposed diagnostic synapomorphies as secondary homologies. On the basis of this study I conclude that a sister group for the Platyhelminthes has not yet been unambiguously established. A clade minimally composed of Neotrochozoa (Mollusca, Sipuncula, Echiura, Annelida) emerges as the most likely sister group of the Nemertea on the basis of morphological and total evidence analyses. Finally, morphological data currrently favor a sister group relationship of Gnathostomulida and Syndermata (probably plus Micrognathozoa). In contrast, molecular or total evidence analyses have not identified a reliable sister group of Gnathostomulida.Further progress in our understanding of metazoan phylogeny crucially depends on the improvement of the quality of currently adopted cladistic data matrices. A thorough reassessment of many of the more than 70 morphological characters discussed here is necessary. Despite the recent compilation of comprehensive data matrices, the power to test competing hypotheses of higher-level metazoan relationships is critically compromised due to uncritical data selection and poor character study in even the most recently published cladistic analyses.

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