Molecular Mechanisms and Evolutionary Consequences of Spore Killers in Ascomycetes

2021 ◽  
Author(s):  
Sarah Zanders ◽  
Hanna Johannesson
Keyword(s):  
Sexual Reproduction ◽  
Molecular Mechanisms ◽  
Meiotic Drive ◽  
Fungal Spore ◽  
Next Generation ◽  
Evolutionary Consequences

In this review, we examine the fungal spore killers. These are meiotic drive elements that cheat during sexual reproduction to increase their transmission into the next generation.

scholarly journals Next Generation Sequencing for the Prediction of the Antibiotic Resistance in Helicobacter pylori: A Literature Review

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 437
Author(s):  
Ilaria Maria Saracino ◽  
Matteo Pavoni ◽  
Angelo Zullo ◽  
Giulia Fiorini ◽  
Tiziana Lazzarotto ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Next Generation Sequencing ◽  
Literature Review ◽  
Molecular Mechanisms ◽  
World Health ◽  
Next Generation ◽  
Culture Methods ◽  
Phenotypic Resistance ◽  
H Pylori ◽  
Generation Sequencing

Background and aims: Only a few antimicrobials are effective against H. pylori, and antibiotic resistance is an increasing problem for eradication therapies. In 2017, the World Health Organization categorized clarithromycin resistant H. pylori as a “high-priority” bacterium. Standard antimicrobial susceptibility testing can be used to prescribe appropriate therapies but is currently recommended only after the second therapeutic failure. H. pylori is, in fact, a “fastidious” microorganism; culture methods are time-consuming and technically challenging. The advent of molecular biology techniques has enabled the identification of molecular mechanisms underlying the observed phenotypic resistance to antibiotics in H. pylori. The aim of this literature review is to summarize the results of original articles published in the last ten years, regarding the use of Next Generation Sequencing, in particular of the whole genome, to predict the antibiotic resistance in H. pylori.Methods: a literature research was made on PubMed. The research was focused on II and III generation sequencing of the whole H. pylori genome. Results: Next Generation Sequencing enabled the detection of novel, rare and complex resistance mechanisms. The prediction of resistance to clarithromycin, levofloxacin and amoxicillin is accurate; for other antimicrobials, such as metronidazole, rifabutin and tetracycline, potential genetic determinants of the resistant status need further investigation.

scholarly journals Dual Role of Metallic Trace Elements in Stress Biology—From Negative to Beneficial Impact on Plants

2019 ◽  
Vol 20 (13) ◽  
pp. 3117 ◽  
Author(s):  
Ewa Muszyńska ◽  
Mateusz Labudda
Keyword(s):  
Trace Elements ◽  
Molecular Mechanisms ◽  
Plant Protection ◽  
Model Systems ◽  
Elevated Concentration ◽  
Metallic Ions ◽  
Beneficial Effects ◽  
Metallic Trace Elements ◽  
Beneficial Impact ◽  
Evolutionary Consequences

Heavy metals are an interesting group of trace elements (TEs). Some of them are minutely required for normal plant growth and development, while others have unknown biological actions. They may cause injury when they are applied in an elevated concentration, regardless of the importance for the plant functioning. On the other hand, their application may help to alleviate various abiotic stresses. In this review, both the deleterious and beneficial effects of metallic trace elements from their uptake by roots and leaves, through toxicity, up to the regulation of physiological and molecular mechanisms that are associated with plant protection against stress conditions have been briefly discussed. We have highlighted the involvement of metallic ions in mitigating oxidative stress by the activation of various antioxidant enzymes and emphasized the phenomenon of low-dose stimulation that is caused by non-essential, potentially poisonous elements called hormesis, which is recently one of the most studied issues. Finally, we have described the evolutionary consequences of long-term exposure to metallic elements, resulting in the development of unique assemblages of vegetation, classified as metallophytes, which constitute excellent model systems for research on metal accumulation and tolerance. Taken together, the paper can provide a novel insight into the toxicity concept, since both dose- and genotype-dependent response to the presence of metallic trace elements has been comprehensively explained.

scholarly journals ‘Meiotic genes’ are constitutively expressed in an asexual amoeba and are not necessarily involved in sexual reproduction

2019 ◽  
Vol 15 (3) ◽  
pp. 20180871 ◽  
Author(s):  
Sutherland K. Maciver ◽  
Zisis Koutsogiannis ◽  
Alvaro de Obeso Fernández del Valle
Keyword(s):  
Homologous Recombination ◽  
Sexual Reproduction ◽  
Asexual Reproduction ◽  
Shotgun Sequencing ◽  
Ancestral State ◽  
Rna Seq ◽  
Next Generation ◽  
Related Process

The amoebae (and many other protists) have traditionally been considered as asexual organisms, but suspicion has been growing that these organisms are cryptically sexual or are at least related to sexual lineages. This contention is mainly based on genome studies in which the presence of ‘meiotic genes’ has been discovered. Using RNA-seq (next-generation shotgun sequencing, identifying and quantifying the RNA species in a sample), we have found that the entire repertoire of meiotic genes is expressed in exponentially growing Acanthamoeba and we argue that these so-called meiotic genes are involved in the related process of homologous recombination in this amoeba. We contend that they are only involved in meiosis in other organisms that indulge in sexual reproduction and that homologous recombination is important in asexual protists as a guard against the accumulation of mutations. We also suggest that asexual reproduction is the ancestral state.

scholarly journals Molecular Mechanisms of Resistance to FLT3 Inhibitors in Acute Myeloid Leukemia: Ongoing Challenges and Future Treatments

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2493
Author(s):  
Sebastian Scholl ◽  
Maximilian Fleischmann ◽  
Ulf Schnetzke ◽  
Florian H. Heidel
Keyword(s):  
Acute Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Continuous Treatment ◽  
Next Generation ◽  
Secondary Resistance ◽  
Development Of Resistance ◽  
Flt3 Inhibitors ◽  
Acute Myeloid

Treatment of FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD)-positive acute myeloid leukemia (AML) remains a challenge despite the development of novel FLT3-directed tyrosine kinase inhibitors (TKI); the relapse rate is still high even after allogeneic stem cell transplantation. In the era of next-generation FLT3-inhibitors, such as midostaurin and gilteritinib, we still observe primary and secondary resistance to TKI both in monotherapy and in combination with chemotherapy. Moreover, remissions are frequently short-lived even in the presence of continuous treatment with next-generation FLT3 inhibitors. In this comprehensive review, we focus on molecular mechanisms underlying the development of resistance to relevant FLT3 inhibitors and elucidate how this knowledge might help to develop new concepts for improving the response to FLT3-inhibitors and reducing the development of resistance in AML. Tailored treatment approaches that address additional molecular targets beyond FLT3 could overcome resistance and facilitate molecular responses in AML.

scholarly journals Meiotic drive mechanisms: lessons from Drosophila

2019 ◽  
Vol 286 (1913) ◽  
pp. 20191430 ◽  
Author(s):  
Cécile Courret ◽  
Ching-Ho Chang ◽  
Kevin H.-C. Wei ◽  
Catherine Montchamp-Moreau ◽  
Amanda M. Larracuente
Keyword(s):  
Small Rna ◽  
Molecular Mechanisms ◽  
Meiotic Drive ◽  
Gene Duplications ◽  
Arms Races ◽  
Transport Pathways ◽  
Selfish Genetic Elements ◽  
Genetic Origins ◽  
Drive Systems ◽  
Rna Pathways

Meiotic drivers are selfish genetic elements that bias their transmission into gametes, often to the detriment of the rest of the genome. The resulting intragenomic conflicts triggered by meiotic drive create evolutionary arms races and shape genome evolution. The phenomenon of meiotic drive is widespread across taxa but is particularly prominent in the Drosophila genus. Recent studies in Drosophila have provided insights into the genetic origins of drivers and their molecular mechanisms. Here, we review the current literature on mechanisms of drive with an emphasis on sperm killers in Drosophila species. In these systems, meiotic drivers often evolve from gene duplications and targets are generally linked to heterochromatin. While dense in repetitive elements and difficult to study using traditional genetic and genomic approaches, recent work in Drosophila has made progress on the heterochromatic compartment of the genome. Although we still understand little about precise drive mechanisms, studies of male drive systems are converging on common themes such as heterochromatin regulation, small RNA pathways, and nuclear transport pathways. Meiotic drive systems are therefore promising models for discovering fundamental features of gametogenesis.

scholarly journals How to use new biology to guide therapy in multiple myeloma

Hematology ◽  
2012 ◽  
Vol 2012 (1) ◽  
pp. 342-349 ◽  
Author(s):  
Gareth J. Morgan ◽  
Martin F. Kaiser
Keyword(s):  
Multiple Myeloma ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Survival Rates ◽  
Current Treatment ◽  
Next Generation ◽  
Molecular Subgroups ◽  
Treatment Protocols ◽  
Sequencing Technologies ◽  
A Genome

Abstract Recent advances in multiple myeloma (MM) therapy have led to significantly longer median survival rates and some patients being cured. At the same time, our understanding of MM biology and the molecular mechanisms driving the disease is constantly improving. Next-generation sequencing technologies now allow insights into the genetic aberrations in MM at a genome-wide scale and across different developmental stages in the course of an individual tumor. This improved knowledge about MM biology needs to be rapidly translated and transformed into diagnostic and therapeutic applications to finally achieve cure in a larger proportion of patients. As a part of these translational efforts, novel drugs that inhibit oncogenic proteins overexpressed in defined molecular subgroups of the disease, such as FGFR3 and MMSET in t(4;14) MM, are currently being developed. The potential of targeted next-generation diagnostic tests to rapidly identify clinically relevant molecular subgroups is being evaluated. The technical tools to detect and define tumor subclones may potentially become clinically relevant because intraclonal tumor heterogeneity has become apparent in many cancers. The emergence of different MM subclones under the selective pressure of treatment is important in MM, especially in the context of maintenance therapy and treatment for asymptomatic stages of the disease. Finally, novel diagnostic and therapeutic achievements have to be implemented into innovative clinical trial strategies with smaller trials for molecularly defined high-risk patients and large trials with a long follow-up for the patients most profiting from the current treatment protocols. These combined approaches will hopefully transform the current one-for-all care into a more tailored, individual therapeutic strategy for MM patients.

scholarly journals Variation in sexual reproduction in orchids and its evolutionary consequences: a spasmodic journey to diversification

2004 ◽  
Vol 84 (1) ◽  
pp. 1-54 ◽  
Author(s):  
RAYMOND L. TREMBLAY ◽  
JAMES D. ACKERMAN ◽  
JESS K. ZIMMERMAN ◽  
RICARDO N. CALVO
Keyword(s):  
Sexual Reproduction ◽  
Evolutionary Consequences

scholarly journals A Mitogen-Activated Protein Kinase Gene (MGV1) in Fusarium graminearum Is Required for Female Fertility, Heterokaryon Formation, and Plant Infection

2002 ◽  
Vol 15 (11) ◽  
pp. 1119-1127 ◽  
Author(s):  
Zhanming Hou ◽  
Chaoyang Xue ◽  
Youliang Peng ◽  
Talma Katan ◽  
H. Corby Kistler ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sexual Reproduction ◽  
Fusarium Graminearum ◽  
Magnaporthe Grisea ◽  
Molecular Mechanisms ◽  
Female Fertility ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Gene ◽  
Heterokaryon Formation ◽  
Plant Infection

Fusarium graminearum is an important pathogen of small grains and maize in many areas of the world. Infected grains are often contaminated with mycotoxins harmful to humans and animals. During the past decade, F. graminearum has caused several severe epidemics of head scab in wheat and barley. In order to understand molecular mechanisms regulating fungal development and pathogenicity in this pathogen, we isolated and characterized a MAP kinase gene, MGV1, which is highly homologous to the MPS1 gene in Magnaporthe grisea. The MGV1 gene was dispensable for conidiation in F. graminearum but essential for female fertility during sexual reproduction. Vegetative growth of mgv1 deletion mutants was normal in liquid media but reduced on solid media. Mycelia of the mgv1 mutants had weak cell walls and were hypersensitive to cell wall degrading enzymes. Interestingly, the mgv1 mutants were self-incompatible when tested for heterokaryon formation, and their virulence was substantially reduced. The ability of the mutants to accumulate trichothecene mycotoxins on inoculated wheat was also greatly reduced. Our data suggest that MGV1 in F. graminearum is involved in multiple developmental processes related to sexual reproduction, plant infection, and cell wall integrity.

scholarly journals Identification of 13 novel USH2A mutations in Chinese retinitis pigmentosa and Usher syndrome patients by targeted next-generation sequencing

2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Ling-hui Qu ◽  
Xin Jin ◽  
Yan-ling Long ◽  
Jia-yun Ren ◽  
Chuang-huang Weng ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Retinitis Pigmentosa ◽  
Molecular Mechanisms ◽  
Usher Syndrome ◽  
Next Generation ◽  
Chinese Families ◽  
Targeted Next Generation Sequencing ◽  
Pathogenic Mutations ◽  
Basement Membrane Protein ◽  
Generation Sequencing

Abstract Background: The USH2A gene encodes usherin, a basement membrane protein that is involved in the development and homeostasis of the inner ear and retina. Mutations in USH2A are linked to Usher syndrome type II (USH II) and non-syndromic retinitis pigmentosa (RP). Molecular diagnosis can provide insight into the pathogenesis of these diseases, facilitate clinical diagnosis, and identify individuals who can most benefit from gene or cell replacement therapy. Here, we report 21 pathogenic mutations in the USH2A gene identified in 11 Chinese families by using the targeted next-generation sequencing (NGS) technology. Methods: In all, 11 unrelated Chinese families were enrolled, and NGS was performed to identify mutations in the USH2A gene. Variant analysis, Sanger validation, and segregation tests were utilized to validate the disease-causing mutations in these families. Results: We identified 21 pathogenic mutations, of which 13, including 5 associated with non-syndromic RP and 8 with USH II, have not been previously reported. The novel variants segregated with disease phenotype in the affected families and were absent from the control subjects. In general, visual impairment and retinopathy were consistent between the USH II and non-syndromic RP patients with USH2A mutations. Conclusions: These findings provide a basis for investigating genotype–phenotype relationships in Chinese USH II and RP patients and for clarifying the pathophysiology and molecular mechanisms of the diseases associated with USH2A mutations.

scholarly journals Synaptonemal Complex dimerization regulates chromosome alignment and crossover patterning in meiosis

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009205
Author(s):  
Spencer G. Gordon ◽  
Lisa E. Kursel ◽  
Kewei Xu ◽  
Ofer Rog
Keyword(s):  
Sexual Reproduction ◽  
Synaptonemal Complex ◽  
Sequence Homology ◽  
Genetic Information ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Homologous Chromosomes ◽  
Local Sequence ◽  
Chromosome Alignment ◽  
Dimerization Interface

During sexual reproduction the parental homologous chromosomes find each other (pair) and align along their lengths by integrating local sequence homology with large-scale contiguity, thereby allowing for precise exchange of genetic information. The Synaptonemal Complex (SC) is a conserved zipper-like structure that assembles between the homologous chromosomes, bringing them together and regulating exchanges between them. However, the molecular mechanisms by which the SC carries out these functions remain poorly understood. Here we isolated and characterized two mutations in the dimerization interface in the middle of the SC zipper in C. elegans. The mutations perturb both chromosome alignment and the regulation of genetic exchanges. Underlying the chromosome-scale phenotypes are distinct alterations to the way SC subunits interact with one another. We propose a model whereby the SC brings homologous chromosomes together through two activities: obligate zipping that prevents assembly on unpaired chromosomes; and a tendency to extend pairing interactions along the entire length of the chromosomes.

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