Biology subjects

Diwanji, V.

Publications and source records attributed to Diwanji, V..

2 recordsLinked to original sources

bioRxiv2023

CTCF is essential for proper mitotic spindle structure and anaphase segregation

Mitosis is an essential process in which the duplicated genome is segregated equally into two daughter cells. CTCF has been reported to be present in mitosis but its importance for mitotic fidelity remains to be determined. To evaluate the importance of CTCF in mitosis, we tracked mitotic behaviors in wild type and two different CTCF CRISPR-based genetic knockdowns. We find that knockdown of CTCF results in prolonged mitoses and failed anaphase segregation via time lapse imaging of SiR-DNA. CTCF knockdown did not alter cell cycling or the mitotic checkpoint, which was activated upon nocodazole treatment. Immunofluorescence imaging of the mitotic spindle in CTCF knockdowns revealed disorganization via tri/tetrapolar spindles and chromosomes behind the spindle pole. Imaging of interphase nuclei showed that nuclear size increased drastically, consistent with failure to divide the duplicated genome in anaphase. Population measurements of nuclear shape in CTCF knockdowns do not display decreased circularity or increased nuclear blebbing relative to wild type. However, failed mitoses do display abnormal nuclear morphologies relative to successful mitoses, suggesting population images do not capture individual behaviors. Thus, CTCF is important for both proper metaphase organization and anaphase segregation which impacts the size and shape of the interphase nucleus.

cell biology↗

bioRxiv2022

Chitosan diet alters the microbiome of adult house flies

House flies are disease vectors, carrying human pathogens which include Escherichia coli and Vibrio cholera. To explore the use of chitosan as a bioinsecticide, we evaluated the effects of a chitosan-amended diet on Musca domestica (house fly). We first conducted longevity experiments to understand the impact of chitosan on house fly longevity. We confirmed that chitosan diet amendment is associated with reduced longevity and that this is not due to starvation. We then extracted fly microbiome DNA and used 16S ribosomal RNA gene amplicon sequencing and quantitative PCR to assess the composition and load of the microbiome for flies fed chitosan-amended diets compared to controls. Diversity of the chitosan-fed fly microbiomes was lower than the control, with significant dissimilarities in community composition. Chitosan-fed flies showed lower Ralstonia relative abundance but increased relative abundance of Serratia. Both control and chitosan-fed flies had highly uneven communities, but the control flies were dominated by genera Ralstonia and Providencia, while the chitosan-fed flies were dominated by genera Serratia, Kosakonia, and Providencia. Contrary to our expected results, chitosan-fed flies also contained 56% more bacteria compared to controls. Gut microbiome changes appear to result from chitinolytic bacteria becoming more relatively abundant, and our results suggest that chitosan-amended diet alters the house fly microbiome resulting in higher fly mortality.

microbiology↗