Category Archives: chytridomycota

Postdoc: UMichigan Fungal Genomics

The lab of Tim James in the Department of Ecology and Evolutionary Biology at the University of Michigan is looking to hire a postdoctoral fellow in the area of single cell and comparative genomics. The research is centered on understanding the phylogeny and molecular evolution of uncultured and poorly known fungi, including the Cryptomycetes, Zygomycetes, and Chytridiomycetes through genomic analyses. The ultimate goals of the project are to produce a well-resolved phylogeny of the basal branches of the fungal kingdom, to identify key evolutionary events associated with diversification and reproduction, and to use genomics to predict ecological roles of uncultured lineages. A major component of the work will be to develop or improve methods for sequencing fungal genomes and transcriptomes using single or few cells or genome assembly using metagenomic approaches. This work will involve collaborations with the ZyGOLife research network (zygolife.org) and the Joint Genome Institute (JGI). The projects are supported by NSF and two JGI Community Sequencing Projects.

The ideal candidate will be skilled in bioinformatics, molecular biology, and microbiology with an interest in fungi. Preference will be given to candidates with proficiency in both bioinformatics and molecular biology. Possible duties include environmental sampling, cell sorting (FACS, micromanipulation), microscopy, genome assembly and annotation, and comparative analyses of genome evolution. Opportunities for mentoring undergraduates or research associates will be provided. The initial appointment is for one year with a possibility of extension to a second year pending performance review.

Our lab (www.umich.edu/~mycology) pursues diverse projects in mycology, and the environment is conducive to development of a pathway to independence in academic research. The lab is in the Department of Ecology and Evolutionary Biology (http://www.eeb.lsa.umich.edu/eeb/index.html), which has strengths in phylogenetics, evolutionary genomics, and disease ecology.

Interested applicants should email Tim James (tyjames@umich.edu) with a CV, cover letter, and the names and contact information of three references.

Anticipated Start Date: Between Oct. 1, 2016 and Jan. 1, 2017.

The University of Michigan is a non-discriminatory/affirmative action employer. The Department of Ecology & Evolutionary Biology at the University of Michigan harbors multiple labs with a focus on evolutionary genetics (http://www.lsa.umich.edu/eeb).

Timothy Y. James
Associate Professor
Associate Curator of Fungi
Department of Ecology and Evolution
University of Michigan
Ann Arbor, MI 48109
734-615-7753
tyjames@umich.edu
http://www.umich.edu/~mycology/

Postdoc: Early diverging fungi in the James lab at U. Michigan

The James Lab at the University of Michigan is looking to hire a postdoctoral fellow in the area of single cell and comparative genomics. The research is centered on understanding the phylogeny, life cycles, and nutrition of early diverging fungi, including the Zygomycetes, Cryptomycetes, and Chytridiomycetes through genomic analyses. The ultimate goals of the project are to produce a well-resolved phylogeny of the basal branches of the fungal kingdom, to identify key evolutionary events associated with diversification and reproduction, and to use genomics to predict ecological roles of uncultured lineages. A major component of the work will be to develop or improve methods for sequencing genomes and transcriptomes using single or few cells or genome assembly using metagenomic approaches. This work will involve collaborations with the ZyGOLife research network (zygolife.org) and the Joint Genome Institute (JGI). The projects are supported by NSF and two JGI Community Sequencing Projects.

The ideal candidate will be skilled in bioinformatics, molecular biology, and cultivation/microscopy of fungi. Preference will be given to candidates with proficiency in both bioinformatics and molecular biology. Possible duties include environmental sampling, cell sorting (FACS, micromanipulation), microscopy, genome assembly and annotation, and comparative analyses of genome evolution. Opportunities for mentoring undergraduates or research associates will be provided. The initial appointment is for one year with a possibility of extension to a second year pending performance review.

Our lab (www.umich.edu/~mycology) pursues diverse projects in mycology, and the environment is conducive to development of a pathway to independence in academic research. The lab is in the Department of Ecology and Evolutionary Biology (http://www.eeb.lsa.umich.edu/eeb/index.html), which has strengths in phylogenetics, evolutionary genomics, and disease ecology.

Interested applicants should email Tim James (tyjames@umich.edu) with a CV, cover letter, and the names and contact information of three references.

Dynamics of amphibian pathogen infection cycles

ResearchBlogging.org
Two papers out this week on the population dynamics and epidemiology of the chytrid pathogen of amphibians, Batrachochytrium dendrobatidis (Bd). This is work from the Vredenburg and Briggs labs that includes several decade-long studies of frog declines and the prevalence of Bd.

See Vance in action swabbing a frog

In the Briggs et al paper, they describe a 5-year study on the fungal load in surviving populations of frogs in Sierra Nevada mountain lakes.  They find that adult frogs that have low enough fungal load escape chytridiomycosis and can actually lose and regain infection. They propose that fungal load dynamics are the reason behind differential survival of various populations of mountain frogs. They conclude that:

“Importantly, model results suggest that host persistence versus extinction does not require differences in host susceptibility, pathogen virulence, or environmental conditions, and may be just epidemic and endemic population dynamics of the same host–pathogen system.”

So they propose that differences in the populations that are coming down with the disease is due only to “density-dependent host–pathogen dynamics” not that some populations are resistant. They go on to provide a detailed model of persistence if the host and pathogen, chance of reinfection, and survival of the host which is derived from the long-term study data.  There are many more interesting findings and models proposed in the paper. It also further reinforces (for me) the need to know more about the molecular basis of the host-pathogen interactions and more about how the fungus persists without a host, lifestyle of how it overwinters, and the details of the microbe-host interactions, and the infection dynamic when zoospores disperse from infected frogs.

The Vrendenburg et al paper adresses the dynamics of population decline in the mountain yellow-legged frogs over a periods of 1-5 and 9-13 year study in 3 different study sites at different sampling intervals.  The authors were able to catalog the species decline and conduct skin swabbing to assess Bd prevalence. They found that the fungus spread quickly as it could detected in virtually all the lakes over the course of a year starting with a 2004 survey. The dramatic declines of frog populations in these lakes followed in the years subsequent to the initial detection. This sadly predicts that most if not all of the mountain lakes will go extinct for the frogs as the current tadpoles develop into frogs in the next 3 years and then fall victim to Bd. Based on their sampling work, the authors were also able to correlate what fungal burden predicted a subsequent decline – in populations where more the ~10,000 zoospores were detected in a swab from frog skin, then the frog population was about to experience a sharp decline.  The take-home from this work is that finding ways to keep the intensity of fungal infections down could provide a meaningful intervention that could prolong the viability of the population.

Briggs, C., Knapp, R., & Vredenburg, V. (2010). Enzootic and epizootic dynamics of the chytrid fungal pathogen of amphibians Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0912886107


Vredenburg, V., Knapp, R., Tunstall, T., & Briggs, C. (2010). Dynamics of an emerging disease drive large-scale amphibian population extinctions Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0914111107

Early branching genomes available

Genome sequencing is underway on several early branches in the Opisthokont and some related linages as part of the “Origins of Multicellularity” project at the Broad Institute (BI) include some recently made available assemblies for:

  • Allomyces macrogynus (Blastocladiomycota “Chytrid”)
  • Capsaspora owczarzaki (Ichthyosporea)

Already available data from

Still in progress (BI)

Still in progress (Other centers)

Amphibian skin bacteria shown to fight off Batrachochytrium dendrobatidis.

A year ago researchers at James Madison University discovered that, Pedobacter cryoconitis, a bacteria first found on the skin of red backed salamanders, was found to prevent the growth of the chytrid B. dendrobatidis, which is currently decimating frog populations.

(Mountain Yellow-Legged Frog from wikipedia)

The newest research on the subject is being presented this year at ASM by Brianna Lam who worked with other biologists from both San Francisco State University and JMU.

Lam’s research indicates that adding pedobacter to the skin of mountain yellow-legged frogs would lessen the effects of Batrachochytrium dendrobatidis (Bd), a lethal skin pathogen that is threatening remaining populations of the frogs in their native Sierra Nevada habitats.

Lam first conducted petri dish experiments that clearly showed the skin bacteria repelling the deadly fungus. She then tested pedobacter on live infected frogs, bathing some of them in a pedobacter solution. The frogs bathed in pedobacter solution lost less weight than those in a control group of infected frogs that were not inoculated.

In addition to the lab experiments, the JMU and SFSU researchers have studied the yellow-legged frogs in their natural habitats and discovered that some populations with the lethal skin disease survive while others go extinct. The populations that survived had significantly higher proportions of individuals with anti-Bd bacteria. The results strongly suggest that a threshold frequency of individuals need to have anti-Bd bacteria to allow a population to persist with Bd. (from Eureka alert)

The research above is really interesting and I am curious as to how the bacteria is actually killing the chytrid. The only other research I can think of where chytrids were being killed was a BBC news article that wrote about scientists bathing frogs in chloramphenicol.

B. dendrobatidis strain JAM81 released

B.dendrobatidis zoosporeThe following is an announcement to the B.dendrobatidis and fungal community at large from Alan Kuo at JGI. This is the JAM81 strain (Jess Morgan collected from a frog in the California Sierra Nevada). The JEL423 (Joyce Longcore, collected in Panama) strain genome sequence and annotation is available from the Broad Institute.

Please do contact me if you would like to contribute to assigning functions to the annotation. We’re in the last round of analyses for some of the genome work, but if there are particular questions you want to contribute to, we’re open to collaborators and can outline the basis of our work to see how other work can complement it.

From Alan Kuo at JGI:

The JGI Batrachochytrium annotation portal is now on the public JGI website. As it is public, no password is required.

For those of you who have not yet registered to be an annotator, go to this new link to register.As before, please choose a username that is personal, so that other annotators may be able to recognize it as yours. A derivative of your personal name would be best.

Those of you who are already registered, you do not need to do anything. Your old pre-release username and password are valid on the new public portal too.

As always, please direct all questions and problems to me. Use email or phone: Cheers, Alan.

Some information about the assembly and annotation:

The first annotation of the 127 scaffolds and 24 Mbp of JGI’s 8.74X assembly of the Batrachochytrim dendrobatidis JAM81 genome. We predict 8732 genes, with the following average properties:

Gene length 1825.16 nt
Transcript length 1407.29 nt
Protein length 450.56 aa
Exon frequency 4.29 exons/gene
Exon length 328.37 nt
Intron length 129.18 nt
Gene density 359.1 genes/Mbp scaffold

The genes were found by the following methods:
Total models 8732 (100%)
Jason’s models 3214 (37%)
cDNAs and ESTs 518 (6%)
Similarity to nr 1928 (22%)
ab initio 3072 (35%)

The genes were validated by the following evidence:
start+stop codons 7990 (92%)
EST support 2488 (28%)
nr hit 6787 (78%)
Pfam hit 4329 (50%)

Fungus Finds Frogs, Frogs Croak

Frogs have been having a tough time of it lately. While there are likely many contributing factors to the global frog decline, one known cause of frog dieoff is a fungal pathogen: Batrachochytrium dendrobatidis. Unfortunately, little is known about how this aquatic fungus kills frogs or how the disease was originated and spread.

However, Dr. Jess Morgan and colleagues published in PNAS (open access article) this week a study aimed at answering the latter questions. Specifically, the authors investigated Batrachochytrium populations in the Sierra Nevada Mountains and sampled the genetic diversity. A clonal population structure with few genotypes indicates that the fungus is new to the region as it hasn’t had time to accumulate mutations. Conversely, should the disease be endemic, there should be many distinct genotypes. Without giving too much of the punchline away, the authors find evidence for an epidemic spread, though certain locations have populations that are recombining.  Any migration of the fungus may even be human assisted.  It will be interesting to see how the disease is controlled and the authors raise a good point here: distribution of resistant sporangia may make it easy for the organism to spread and remain dormant.  As a result, this may be a particularly tough disease to control.