scholarly journals Chlamydospore Formation during Hyphal Growth in Cryptococcus neoformans

2005 ◽  
Vol 4 (10) ◽  
pp. 1746-1754 ◽  
Author(s):  
Xiaorong Lin ◽  
Joseph Heitman
Keyword(s):  
Cryptococcus Neoformans ◽  
Pathogenic Fungus ◽  
Hyphal Growth ◽  
Filamentous Growth ◽  
Term Survival ◽  
Glycogen Accumulation ◽  
Chlamydospore Formation ◽  
Energy Store

ABSTRACT Cryptococcus neoformans, a basidiomycetous fungal pathogen, infects hosts through inhalation and can cause fatal meningoencephalitis in individuals if untreated. This fungus undergoes a dimorphic transition from yeast to filamentous growth during mating and monokaryotic fruiting, which leads to the production of hyphae and airborne infectious basidiospores. Here we characterized a novel morphological feature associated with the filamentous stages of the life cycle of C. neoformans which resembles resting or survival structures known as chlamydospores in other fungi. The C. neoformans chlamydospore-like structure is rich in glycogen, suggesting that it might have a role as an energy store. However, characterization of mutants with decreased or increased levels of glycogen production showed that glycogen levels have little effect on filamentous growth, sporulation, or chlamydospore formation. These results suggest that the formation of chlamydospores is independent of glycogen accumulation level. We also show that chlamydospore formation does not require successful sporulation and that the presence of chlamydospores is not sufficient for sporulation. Although the biological functions of chlamydospores remain to be established for this pathogenic fungus, their formation appears to be an integral part of the filamentation process, suggesting that they could be necessary to support sexual sporulation under adverse conditions and thereby facilitate the production of infectious basidiospores or long-term survival propagules in harsh environments.

scholarly journals Characterization of the mbsA Gene Encoding a Putative APSES Transcription Factor in Aspergillus fumigatus

2021 ◽  
Vol 22 (7) ◽  
pp. 3777
Author(s):  
Yong-Ho Choi ◽  
Sang-Cheol Jun ◽  
Min-Woo Lee ◽  
Jae-Hyuk Yu ◽  
Kwang-Soo Shin
Keyword(s):  
Aspergillus Fumigatus ◽  
Pathogenic Fungus ◽  
Hyphal Growth ◽  
Spore Wall ◽  
Mrna Levels ◽  
Chitin Synthesis ◽  
Helix Loop Helix ◽  
Growth Development ◽  
Opportunistic Pathogenic

The APSES family proteins are transcription factors (TFs) with a basic helix-loop-helix domain, known to regulate growth, development, secondary metabolism, and other biological processes in Aspergillus species. In the genome of the human opportunistic pathogenic fungus Aspergillus fumigatus, five genes predicted to encode APSES TFs are present. Here, we report the characterization of one of these genes, called mbsA (Afu7g05620). The deletion (Δ) of mbsA resulted in significantly decreased hyphal growth and asexual sporulation (conidiation), and lowered mRNA levels of the key conidiation genes abaA, brlA, and wetA. Moreover, ΔmbsA resulted in reduced spore germination rates, elevated sensitivity toward Nikkomycin Z, and significantly lowered transcripts levels of genes associated with chitin synthesis. The mbsA deletion also resulted in significantly reduced levels of proteins and transcripts of genes associated with the SakA MAP kinase pathway. Importantly, the cell wall hydrophobicity and architecture of the ΔmbsA asexual spores (conidia) were altered, notably lacking the rodlet layer on the surface of the ΔmbsA conidium. Comparative transcriptomic analyses revealed that the ΔmbsA mutant showed higher mRNA levels of gliotoxin (GT) biosynthetic genes, which was corroborated by elevated levels of GT production in the mutant. While the ΔmbsA mutant produced higher amount of GT, ΔmbsA strains showed reduced virulence in the murine model, likely due to the defective spore integrity. In summary, the putative APSES TF MbsA plays a multiple role in governing growth, development, spore wall architecture, GT production, and virulence, which may be associated with the attenuated SakA signaling pathway.

Abstract A17: Characterization of primary-metastasis pairs in high-grade serous ovarian cancer with short- and long-term survival

2020 ◽  
Author(s):  
Emilee N. Kotnik ◽  
Nicholas C. Spies ◽  
Christopher A. Miller ◽  
Tiandao Li ◽  
Matthew Inkman ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
High Grade ◽  
Serous Ovarian Cancer ◽  
Term Survival ◽  
Long Term Survival ◽  
Short And Long Term

scholarly journals Characterization of Long-Term Survival of Syngeneic Hepatocytes in Rat Peritoneum

2003 ◽  
Vol 12 (6) ◽  
pp. 569-578 ◽  
Author(s):  
Clare Selden ◽  
A. Casbard ◽  
M. Themis ◽  
H. J. F. Hodgson
Keyword(s):  
Term Survival ◽  
Long Term Survival

scholarly journals The Heterotrimeric Transcription Factor CCAAT-Binding Complex and Ca 2+ -CrzA Signaling Reversely Regulate the Transition between Fungal Hyphal Growth and Asexual Reproduction

mBio ◽  
2021 ◽  
Author(s):  
Yiran Ren ◽  
Chi Zhang ◽  
Ziqing Chen ◽  
Ling Lu
Keyword(s):  
Transcription Factor ◽  
Asexual Reproduction ◽  
Culture Condition ◽  
Vegetative Growth ◽  
Submerged Culture ◽  
Hyphal Growth ◽  
Asexual Development ◽  
Term Survival ◽  
Vegetative Hyphal Growth

A precisely timed switch between vegetative hyphal growth and asexual development is a crucial process for the filamentous fungal long-term survival, dissemination, biomass production, and virulence. However, under the submerged culture condition, filamentous fungi would undergo constant vegetative growth whereas asexual conidiation rarely occurs.

scholarly journals Identification and molecular characterization of SIV Vpr R50G mutation associated with long term survival in SIV-infected morphine dependent and control macaques

Virology ◽  
2013 ◽  
Vol 446 (1-2) ◽  
pp. 144-151 ◽  
Author(s):  
Ivelisse Rivera ◽  
Yashira García ◽  
Mohitkumar R. Gangwani ◽  
Richard J. Noel ◽  
Lucianette Maldonado ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Term Survival ◽  
Long Term Survival ◽  
And Control

scholarly journals Characterization of Ancient DNA Supports Long-Term Survival of Haloarchaea

Astrobiology ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 553-560 ◽  
Author(s):  
Krithivasan Sankaranarayanan ◽  
Tim K. Lowenstein ◽  
Michael N. Timofeeff ◽  
Brian A. Schubert ◽  
J. Koji Lum
Keyword(s):  
Ancient Dna ◽  
Term Survival ◽  
Long Term Survival

scholarly journals Genomics of peritoneal surface malignancies

2017 ◽  
Author(s):  
Jasvinder Singh ◽  
Anup Sharma ◽  
Nita Ahuja
Keyword(s):  
Response To Therapy ◽  
Prediction Of Response ◽  
Term Survival ◽  
Peritoneal Surface ◽  
Technological Advances ◽  
Appendiceal Neoplasms ◽  
Genomic Characterization ◽  
Peritoneal Surface Malignancies

Peritoneal malignancies and metastasis are traditionally approached as a terminal disease, however with multiple lines of clinical therapy; long-term survival can be achieved in selected patients using aggressive cytoreduction and hyperthermic intraperitoneal chemotherapy. This is especially true for Pseudomyxoma peritonei from appendiceal neoplasms, peritoneal mesothelioma and peritoneal metastasis from colorectal cancer. In this article, we discuss the nature of genomic alterations in these three peritoneal malignancies and their potential as prognostic and therapeutic markers in clinical decisions. Genomic characterization of malignancies using technological advances including what is now widely used and accepted next-generation genomic sequencing methods has identified genomic anomalies (i.e. mutations, epigenetic modifications, transcription and expression changes in RNA) which is used for targeted therapy, prognostication, surveillance and prediction of response to therapy.

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