Biomedical subjects

Susan Kaminskyj

Publications and source records attributed to Susan Kaminskyj.

3 recordsLinked to original sources

PubMed2006

A synchrotron FTIR microspectroscopy investigation of fungal hyphae grown under optimal and stressed conditions.

Synchrotron FTIR can provide high spatial resolution (<10 microm pixel size) in situ biochemical analyses of intact biotissues, an area of increasing importance in the post-genomic era, as gene functions and gene networks are coming under direct scrutiny. With this technique, we can simultaneously assess multiple aspects of cell biochemistry and cytoplasmic composition. In this paper, we report the first results of our synchrotron FTIR examination of hyphae of three important fungal model systems, each with sequenced genomes and a wealth of research: Aspergillus, Neurospora, and Rhizopus. We have analyzed the FTIR maps of Aspergillus nidulans cells containing the hypA1 allele, a well-characterized single-gene temperature-sensitive morphogenetic mutation. The hypA1 cells resemble wildtype at 28 degrees C but have growth defects at 42 degrees C. We have also investigated Neurospora and Rhizopus cultures grown in media with optimal or elevated pH. Significant differences between the spectra of the three fungi are likely related to differences in composition and structure. In addition, high spatial resolution synchrotron FTIR spectroscopy provides an outstanding method for monitoring subtle subcellular changes that accompany environmental stress.

Colony Count, Microbial↗

PubMed2005

Profiling of wheat class III peroxidase genes derived from powdery mildew-attacked epidermis reveals distinct sequence-associated expression patterns.

A cDNA library was constructed from leaf epidermis of diploid wheat (Triticum monococcum) infected with the powdery mildew fungus (Blumeria graminis f. sp. tritici) and was screened for genes encoding peroxidases. From 2,500 expressed sequence tags (ESTs), 36 cDNAs representing 10 peroxidase genes (designated TmPRX1 to TmPRX10) were isolated and further characterized. Alignment of the deduced amino acid sequences and phylogenetic clustering with peroxidases from other plant species demonstrated that these peroxidases fall into four distinct groups. Differential expression and tissue-specific localization among the members were observed during the B. graminis f. sp. tritici attack using Northern blots and reverse-transcriptase polymerase chain reaction analyses. Consistent with its abundance in the EST collection, TmPRX1 expression showed the highest induction during pathogen attack and fluctuated in response to the fungal parasitic stages. TmPRX1 to TmPRX6 were expressed predominantly in mesophyll cells, whereas TmPRX7 to TmPRX10, which feature a putative C-terminal propeptide, were detectable mainly in epidermal cells. Using TmPRX8 as a representative, we demonstrated that its C-terminal propeptide was sufficient to target a green fluorescent protein fusion protein to the vacuoles in onion cells. Finally, differential expression profiles of the TmPRXs after abiotic stresses and signal molecule treatments were used to dissect the potential role of these peroxidases in multiple stress and defense pathways.

Amino Acid Sequence↗

PubMed2004

Aspergillus nidulans hypA regulates morphogenesis through the secretion pathway.

Aspergillus nidulans hypA encodes a predicted 1474 amino acid, 161.9 kDa cytoplasmic peptide. Strains with hypA1 and hypA6 alleles are wild type at 28 degrees C but have wide, slow-growing hyphae and thick walls at 42 degrees C. hypA1 and hypA6 have identical genetic lesions. hypA1 and hypA6 restrictive phenotypes have statistically similar morphometry, and strains with either allele can conidiate at 42 degrees C. hypA deletion strains require osmotic support and have aberrant morphology, but produce viable spores at 28 degrees C. hypA has full-length orthologs in filamentous fungi and yeasts and a 200 amino acid region with similarity to sequences in plants and animals. The Saccharomyces cerevisiae hypA ortholog is TRS120, a regulatory subunit in the TRAPP II complex that mediates traffic through the Golgi equivalent. Enzyme secretion is reduced in hypA1 cells at 42 degrees C. Endomembranes and cytoplasmic actin arrays in hypA1 have weak polarity at 42 degrees C and cytoplasmic microtubules have reduced number and normal distribution.

Amino Acid Sequence↗