882 research outputs found
Truncation of MAT1-2-7 deregulates developmental pathways associated with sexual reproduction in Huntiella omanensis
The MAT1-1-1 and MAT1-2-1 genes are thought to be the master regulators
of sexual development in most ascomycete fungi, and they are often essential for
this process. In contrast, it has been suggested that the secondary mating-type genes
act to calibrate the sexual cycle and can be dispensable. Recent functional characterization
of genes such as Aspergillus fumigatus MAT1-2-4, Huntiella omanensis MAT1-2-7,
and Botrytis cinerea MAT1-1-5 has, however, shown that these secondary genes may
play more central roles in the sexual pathway and are essential for the production of
mature fruiting structures. We used a comparative transcriptome sequencing (RNAseq)
experiment to show that the truncation of MAT1-2-7 in the wood inhabiting H.
omanensis residing in the Ceratocystidaceae is associated with the differential expression
of approximately 25% of all the genes present in the genome, including the
transcriptional regulators ste12, wc-2, sub1, VeA, HMG8, and pro1. This suggests that
MAT1-2-7 may act as a transcription factor and that DMAT1-2-7 mutant sterility is the
result of layered deregulation of a variety of signaling and developmental pathways.
This study is one of only a few that details the functional characterization of a secondary
MAT gene in a nonmodel species. Given that this gene is present in other
Ceratocystidaceae species and that there are diverse secondary MAT genes present
throughout the Pezizomycotina, further investigation into this gene and others like it
will provide a clearer understanding of sexual development in these eukaryotes.
IMPORTANCE Secondary mating-type genes are being described almost as quickly as
new fungal genomes are being sequenced. Understanding the functions of these genes
has lagged behind their description, in part due to limited taxonomic distribution, lack of conserved functional domains, and difficulties with regard to genetic manipulation protocols.
This study aimed to address this by investigating a novel mating-type gene, MAT1-
2-7, for which two independent mutant strains were generated in a previous study. We
characterized the molecular response to the truncation of this gene in a nonmodel,
wood-infecting fungus and showed that it resulted in widespread differential expression
throughout the transcriptome of this fungus. This suggests that secondary MAT genes
may play a more important role than previously thought. This study also emphasizes the
need for further research into the life cycles of nonmodel fungi, which often exhibit
unique features that are very different from the systems understood from model species.The University of Pretoria, the Department of Science and Technology (DST)/National Research Foundation (NRF) Centre of Excellence in Tree Health Biotechnology (CTHB) as well as B.D. Wingfield’s DST/NRF SARChI chair in Fungal Genomics and A. M. Wilson’s DST/NRF Scarce Skills Postdoctoral Fellowship.https://journals.asm.org/journal/spectrumam2023BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog
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Variable responses of human and non-human primate gut microbiomes to a Western diet
BACKGROUND: The human gut microbiota interacts closely with human diet and physiology. To better understand the mechanisms behind this relationship, gut microbiome research relies on complementing human studies with manipulations of animal models, including non-human primates. However, due to unique aspects of human diet and physiology, it is likely that host-gut microbe interactions operate differently in humans and non-human primates. RESULTS: Here, we show that the human microbiome reacts differently to a high-protein, high-fat Western diet than that of a model primate, the African green monkey, or vervet (Chlorocebus aethiops sabaeus). Specifically, humans exhibit increased relative abundance of Firmicutes and reduced relative abundance of Prevotella on a Western diet while vervets show the opposite pattern. Predictive metagenomics demonstrate an increased relative abundance of genes associated with carbohydrate metabolism in the microbiome of only humans consuming a Western diet. CONCLUSIONS: These results suggest that the human gut microbiota has unique properties that are a result of changes in human diet and physiology across evolution or that may have contributed to the evolution of human physiology. Therefore, the role of animal models for understanding the relationship between the human gut microbiota and host metabolism must be re-focused.P40 OD010965 - NIH HHS; P40 RR019963 - NCRR NIH HHS; P51 OD011132 - NIH HHS; R01 RR016300 - NCRR NIH HHS; 5R01RR016300 - NCRR NIH HH
Genetic networks that govern sexual reproduction in the Pezizomycotina
Sexual development in filamentous fungi is a complex process that relies on the precise control of and interaction between a variety of genetic networks and pathways. The mating-type (MAT) genes are the master regulators of this process and typically act as transcription factors, which control the expression of genes involved at all stages of the sexual cycle. In many fungi, the sexual cycle typically begins when the mating pheromones of one mating type are recognized by a compatible partner, followed by physical interaction and fertilization. Subsequently, highly specialized sexual structures are formed, within which the sexual spores develop after rounds of meiosis and mitosis. These spores are then released and germinate, forming new individuals that initiate new cycles of growth. This review provides an overview of the known genetic networks and pathways that are involved in each major stage of the sexual cycle in filamentous ascomycete fungi.https://journals.asm.org/journal/mmbrhj2022BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog
Reflections on the Cost of Low-Cost Whole Genome Sequencing: Framing the Health Policy Debate
The cost of whole genome sequencing is dropping rapidly. There has been a great deal of enthusiasm about the potential for this technological advance to transform clinical care. Given the interest and significant investment in genomics, this seems an ideal time to consider what the evidence tells us about potential benefits and harms, particularly in the context of health care policy. The scale and pace of adoption of this powerful new technology should be driven by clinical need, clinical evidence, and a commitment to put patients at the centre of health care policy
Magnetic Fields in Star-Forming Molecular Clouds II. The Depolarization Effect in the OMC-3 Filament of Orion A
Polarized 850 micron thermal emission data of the region OMC-3 in the Orion A
molecular cloud are presented. These data, taken in 1998 with the SCUBA
polarimeter mounted on the James Clerk Maxwell Telescope, have been re-reduced
using improved software. The polarization pattern is not suggestive of a
uniform field structure local to OMC-3, nor does the orientation of the vectors
align with existing polarimetry maps of the OMC-1 core 20' to the south. The
depolarization toward high intensity regions cannot be explained by uniform
field geometry except in the presence of changing grain structure, which is
most likely to occur in regions of high density or temperature (i.e. the
embedded cores). The depolarization in fact occurs along the length of the
filamentary structure of OMC-3 and is not limited to the vicinity of the bright
cores. Such a polarization pattern is predicted by helical field models for
filamentary clouds. We present three scenarios to explain the observed
polarization pattern of OMC-3 in terms of a helical field geometry. Qualitative
models incorporating a helical field geometry are presented for two cases.Comment: 57 pages, 12 figures, 3 tables; accepted for publication in Ap
Unique patterns of mating pheromone presence and absence could result in the ambiguous sexual behaviors of Colletotrichum species
Colletotrichum species are known to engage in unique sexual behaviors that differ significantly from the mating strategies of other filamentous
ascomycete species. For example, most ascomycete fungi require the expression of both the MAT1-1-1 and MAT1-2-1 genes to induce
sexual reproduction. In contrast, all isolates of Colletotrichum harbor only the MAT1-2-1 gene and yet, are capable of recognizing
suitable mating partners and producing sexual progeny. The molecular mechanisms contributing to mating types and behaviors in
Colletotrichum are, however, unknown. A comparative genomics approach analyzing 35 genomes, representing 31 Colletotrichum species
and two Verticillium species, was used to elucidate a putative molecular mechanism underlying the unique sexual behaviors observed in
Colletotrichum species. The existence of only the MAT1-2 idiomorph was confirmed across all species included in this study. Comparisons
of the loci harboring the two mating pheromones and their cognate receptors revealed interesting patterns of gene presence and absence.
The results showed that these genes have been lost multiple, independent times over the evolutionary history of this genus. These losses
indicate that the pheromone pathway no longer plays an active role in mating type determination, suggesting an undiscovered mechanism
by which mating partner recognition is controlled in these species. This further suggests that there has been a redirection of the underlying
genetic mechanisms that regulate sexual development in Colletotrichum species. This research thus provides a foundation from which further
interrogation of this topic can take place.The South African Department of Science and Innovation’s South African Research Chair Initiative (SARChI); Botanical Resources Australia—Agricultural Services, Pty. Ltd; post-doctoral grant from the University of Pretoria, South Africa; Melbourne International Fee Remission and Melbourne International Research Scholarships from the University of Melbourne, Australia.http://www.g3journal.orgam2022BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog
Magnetic Fields in Star-Forming Molecular Clouds. V. Submillimeter Polarization of the Barnard 1 Dark Cloud
We present 850 micron polarimetry from the James Clerk Maxwell Telescope
toward several dense cores within the dark cloud Barnard 1 in Perseus.
Significant polarized emission is detected from across the mapped area and is
not confined to the locations of bright cores. This indicates the presence of
aligned grains and hence a component of the magnetic field in the plane of the
sky. Polarization vectors detected away from bright cores are strongly aligned
at a position angle of ~ 90 degrees (east of north), while vectors associated
with bright cores show alignments of varying orientations. There is no direct
correlation between the polarization angles measured in earlier optical
polarimetry toward Perseus and the polarized submillimeter thermal emission.
Depolarization toward high intensities is exhibited, but toward the brightest
core reaches a threshold beyond which no further decrease in polarization
percentage is measured. The polarized emission data from the interior envelope
are compared with previously published OH Zeeman data to estimate the total
field strength and orientation under the assumption of a uniform and
non-uniform field component in the region. These results are rough estimates
only due to the single independent detection of Zeeman splitting toward Barnard
1. The uniform field component is thus calculated to be B(0) = 31 microGauss
[+/- (0.52 (north) - 0.01 (east)) - 0.86 (l.o.s.)] in the case where we have
assumed the ratio of the dispersion of the line-of-sight field to the field
strength to be 0.2.Comment: 35 pages, LaTeX, including 4 tables and 5 figures (2 color
Blast from the past : a study of decades-old fungal cultures resolves a long-standing tree disease mystery
DATA AVAILABILITY : The sequences that were generated for this study have been deposited at the NCBI. The accession numbers will be made available upon publication.A root disease in plantations of Pinus radiata and Pinus pinaster, where trees died in distinct patches, was present in the Western Cape province of South Africa during the 1970s and 1980s. Phytophthora cinnamomi was initially believed to be the cause, but the disease was later ascribed to the insect-associated fungus Leptographium serpens, a fungal species residing in the Ophiostomatales. Doubt regarding the cause of the disease was raised in a later study due to the fact that most Leptographium spp., particularly those that colonise ray parenchyma tissues, which is the case for L. serpens, are not typically primary disease agents. In this study, cultures of an unidentified sterile fungus collected from the dying trees were revived and identified using DNA sequencing methods, which were not available when the disease was first studied. These cultures were identified as the pyrophillic pathogen Rhizina undulata, well-known to cause patch death of conifers in South Africa and elsewhere in the world. While the patches of dying trees no longer exist and the disease cannot be newly studied, it is most likely that the tree death originally thought to be caused by L. serpens was due primarily to R. undulata. The study provides a vivid example of the value of preserving cultures of fungi for later study and the power of modern techniques to identify fungal pathogens.The members of the Tree Protection Co-operative Programme (TPCP) and the National Research Foundation (NRF) in South Africa. Open access funding provided by University of Pretoria.https://link.springer.com/journal/42161hj2023BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyPlant Production and Soil Scienc
Child and family experiences with inborn errors of metabolism: a qualitative interview study with representatives of patient groups
Background: Patient-centered health care for children with inborn errors of metabolism (IEM) and their families is important and requires an understanding of patient experiences, needs, and priorities. IEM-specific patient groups have emerged as important voices within these rare disease communities and are uniquely positioned to contribute to this understanding. We conducted qualitative interviews with IEM patient group representatives to increase understanding of patient and family experiences, needs, and priorities and inform patient-centered research and care. Methods: We developed a sampling frame of patient groups representing IEM disease communities from Canada, the United States, and United Kingdom. With consent, we interviewed participants to explore their views on experiences, needs, and outcomes that are most important to children with IEM and their families. We analyzed the data using a qualitative descriptive approach to identify key themes and sub-themes. Results: We interviewed 18 organizational representatives between February 28 and September 17, 2014, representing 16 IEMs and/or disease categories. Twelve participants voluntarily self-identified as parents and/or were themselves patients. Three key themes emerged from the coded data: managing the uncertainty associated with raising and caring for a child with a rare disease; challenges associated with the affected child’s life transitions, and; the collective struggle for improved outcomes and interventions that rare disease communities navigate. Conclusion: Health care providers can support children with IEM and their families by acknowledging and reducing uncertainty, supporting families through children’s life transitions, and contributing to rare disease communities’ progress toward improved interventions, experiences, and outcomes
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