Biology subjects

Krishnavajhala, A.

Publications and source records attributed to Krishnavajhala, A..

4 recordsLinked to original sources

bioRxiv2026

Multi-Omics Characterization of Human Molecular Responses to Spaceflight Across Two Independent Missions

Human spaceflight has historically been led by government agencies, but the emergence of commercial organizations is enabling broader participation and new research opportunities. In this study, we present a comprehensive molecular characterization of early human responses to spaceflight, leveraging multi-omics data across the first three weeks of two commercial missions. Biospecimens from six individuals, four from the Axiom 2 mission (10 days) and two from Axiom 3 (21 days), were analyzed using single-cell and bulk RNA sequencing, alongside proteomic profiling. Individual and integrative analyses of these datasets reveal systemic changes in cell types, transcripts, and proteins related to immune regulation, osteoclast differentiation, NF-{kappa}B signaling, and blood homeostasis pathways. Importantly, several of the detected pathways align with physiological patterns observed in longer-duration missions. This work establishes a foundational resource for understanding early adaptation to spaceflight at the cellular and molecular levels, providing insights to reduce future space-travel health risks. HighlightsO_LIFirst integrated multi-omics analysis using single-cell, bulk RNA sequencing and proteomic profiling of early human spaceflight responses across two commercial missions (Ax-2 and Ax-3). C_LIO_LIDistinct PBMC clustering was observed across Ax-2 and Ax-3, and post-flight samples. It showed fewer monocytes, dendritic cells, and megakaryocytes with increased naive CD4 and cytotoxic T cells. C_LIO_LIMulti-omics integration identifies shared biological signatures, including osteoclast differentiation, metabolic stress, and coagulation changes. C_LIO_LIThese findings lay the foundation for developing countermeasures to protect immune, skeletal, and vascular health during spaceflight. C_LI

molecular biology↗

bioRxiv2026

Microbial Dynamics Across Commercial Spaceflights of Varying Duration

SummarySpaceflight introduces environmental stressors that can alter human microbiomes and immune responses. We analyzed 259 biospecimens from six astronauts across two commercial ISS missions: Axiom 2 (10-day mission) and Axiom 3 (21-day mission). Samples included saliva, stool, urine, and body swabs from 10 anatomical sites, profiled via 16S ribosomal RNA (rRNA) gene sequencing. Gut and oral microbiomes remained stable, while skin-associated communities exhibited transient diversity shifts post-flight. Taxonomic analysis revealed individual and site-specific patterns as well as a possible microbial acquisition from the ISS/space-flight environment and microbiome exclusivity. Cytokine profiling from single cell data indicated immune activation, with IL-32 and IL-16 elevated in Axiom 2 and Axiom 3, coinciding with microbial changes. These findings provide an integrated view of microbiome individuality, exclusivity and immune dynamics during two short-duration commercial spaceflights of three weeks, informing strategies for crew health on future long-duration missions.

microbiology↗

bioRxiv2023

Isolation and genomic characterization of the tick-borne relapsing fever spirochete, Borrelia turicatae, from ticks collected in a peridomestic setting of Camayeca, Mexico

Surveillance studies were implemented in Sinaloa, Mexico to determine the circulation of tick-borne relapsing fever spirochetes. Argasid ticks were collected from a human dwelling in the village of Camayeca and spirochetes were isolated. Genomic analysis indicated that Borrelia turicatae is a threat to those living in resource limited settings. Article Summary LineWe report the collection of argasid ticks from a peridomestic setting in Mexico and the isolation of Borrelia turicatae; increased surveillance efforts are needed on this overlooked vector-borne pathogen.

ecology↗

bioRxiv2023

Vertical transmission of Borrelia turicatae (Spirochaetales: Borreliaceae) by autogenously reproducing Ornithodoros turicata (Ixodida: Argasidae) female naturally infected with the spirochetes

Ornithodoros turicata is a vector of relapsing fever (RF) spirochetes in North America and transmits Borrelia turicatae to a variety of vertebrate hosts. The remarkably long lifespan of O. turicata and its ability to maintain spirochetes horizontally (between life stages) and vertically to progeny promotes the perpetuation of B. turicatae in nature. Nevertheless, the reproductive biology of O. turicata is poorly understood. In this report, we collected ticks from a park within a neighborhood of Austin, Texas. They were reared to adulthood and male ticks were individually housed with females. We observed autogenous reproduction by the ticks and further investigated vertical transmission of B. turicatae by quantifying filial infection rates in a cohort of progeny ticks. These results indicate that O. turicata transovarially transmits B. turicatae during autogenous reproduction and further signify the tick as a natural reservoir of the spirochetes. ImportancePrevious research has implicated Ornithodoros ticks, including Ornithodoros turicata, as long-term reservoirs of relapsing fever (RF) spirochetes. Considering the ticks long lifespan and their efficiency in maintaining and transferring spirochetes within the population, the infection could persist in a given enzootic focus for decades. However, little is known about the relative importance of horizontal and vertical transmission routes in the persistence and evolution of RF Borrelia. Our observations on the reproductive biology of O. turicata in the absence of vertebrate hosts indicate an additional mechanism by which B. turicata can be maintained in the environment. This work establishes the foundation for studying O. turicata reproduction and spirochete-vector interactions, which will aid in devising control measures for Ornithodoros ticks and RF spirochetes.

ecology↗