Isolation and characterization of a Klebsiella strain from smokeless tobacco consumers

Abstract Organisms that reside in the oral cavity become an important aspect of health and disease. Disruption of the oral health and hygiene has been attributed to the presence of abnormal microflora. Consumption of tobacco has been considered to be a leading cause for the presence of abnormal oral microflora, in turn disrupting the oral health. In this study, 45 respondents were targeted from South Mumbai who consumed tobacco in smokeless forms. Klebsiella pneumoniae strain was isolated from oral swabs of smokeless tobacco consumers and compared against controls. The strain was characterized using phenotypic and genotypic approaches. The presence of Klebsiella was reported in 24 of the 45 samples. Sequence comparison of 16S rRNA gene and phylogenetic analysis confirmed the presence of Klebsiella strain. The sequence obtained was submitted to the NCBI Gene bank that has been granted an accession number- KM186520. During the course of our study we observed Klebsiella pneumoniae to exhibit green fluorescent colonies under UV spectroscopy. λmax of the fluorescent chromophore was estimated to be 220 nm with OD of 1.785. Our analysis provides evidence that Klebsiella pneumoniae in the oral micro flora of the tobacco consumers exhibits a novel phenomenon of fluorescence

Cfap97d1 is important for flagellar axoneme maintenance and male mouse fertility

Abstract The flagellum is essential for sperm motility and fertilization in vivo. The axoneme is the main component of the flagella, extending through its entire length. An axoneme is comprised of two central microtubules surrounded by nine doublets, the nexin-dynein regulatory complex, radial spokes, and dynein arms. Failure to properly assemble components of the axoneme in a sperm flagellum, leads to fertility alterations. To understand this process in detail, we have defined the function of an uncharacterized gene, Cfap97 domain containing 1 (Cfap97d1). This gene is evolutionarily conserved in mammals and multiple other species, including Chlamydomonas. We have used two independently generated Cfap97d1 knockout mouse models to study the gene function in vivo. Cfap97d1 is exclusively expressed in testes starting from post-natal day 20 and continuing throughout adulthood. Deletion of the Cfap97d1 gene in both mouse models leads to sperm motility defects (asthenozoospermia) and male subfertility. In vitro fertilization (IVF) of cumulus-intact oocytes with Cfap97d1 deficient sperm yielded few embryos whereas IVF with zona pellucida-free oocytes resulted in embryo numbers comparable to that of the control. Knockout spermatozoa showed abnormal motility characterized by frequent stalling in the anti-hook position. Uniquely, Cfap97d1 loss caused a phenotype associated with axonemal doublet heterogeneity linked with frequent loss of the fourth doublet in the sperm stored in the epididymis. This study demonstrates that Cfap97d1 is required for sperm flagellum ultra-structure maintenance, thereby playing a critical role in sperm function and male fertility in mice

MRNIP interacts with sex body chromatin to support meiotic progression, spermatogenesis, and male fertility in mice

Abstract Meiosis has a principal role in sexual reproduction to generate haploid gametes in both sexes. During meiosis, the cell nucleus hosts a dynamic environment where some genes are transcriptionally activated, and some are inactivated at the same time. This becomes possible through subnuclear compartmentalization. The sex body, sequestering X and Y chromosomes during male meiosis and creating an environment for the meiotic sex chromosome inactivation (MSCI) is one of the best known and studied subnuclear compartments. Herein, we show that MRNIP forms droplet-like accumulations that fuse together to create a distinct subnuclear compartment that partially overlaps with the sex body chromatin during diplotene. We demonstrate that Mrnip−/− spermatocytes have impaired DNA double-strand break (DSB) repair, they display reduced sex body formation and defective MSCI. We show that Mrnip−/− undergoes critical meiocyte loss at the diplotene stage. Furthermore, we determine that DNA DSBs (induced by SPO11) and synapsis initiation (facilitated by SYCP1) precede Mrnip expression in testes. Altogether, our findings indicate that in addition to an emerging role in DNA DSB repair, MRNIP has an essential function in spermatogenesis during meiosis I by forming drop-like accumulations interacting with the sex body