Biology subjects

Gotoh, A.

Publications and source records attributed to Gotoh, A..

5 recordsLinked to original sources

bioRxiv2023

Identification of Core Yeast Species and Microbe-Microbe Interactions Impacting Larval Growth of Drosophila in the Wild

Microbiota consisting of various fungi and bacteria have a significant impact on the physiological functions of the host. However, it is unclear which species are essential to this impact and how they affect the host. This study analyzed and isolated microbes from natural food sources of Drosophila larvae, and investigated their functions. Hanseniaspora uvarum is the predominant yeast responsible for larval growth in the earlier stage of fermentation. As fermentation progresses, Acetobacter orientalis emerges as the key bacterium responsible for larval growth, although yeasts and lactic acid bacteria must coexist along with the bacterium to stabilize this host-bacterial association. By providing nutrients to the larvae in an accessible form, the microbiota contributes to the upregulation of various genes that function in larval cell growth and metabolism. Thus, this study elucidates the key microbial species that support animal growth under microbial transition.

developmental biology↗

bioRxiv2022

Proteomic analysis of spermathecal fluid reveals factors related to long-term sperm storage in ant queens

Ant queens can maintain a large number of sperm cells for over a decade after mating at the beginning of their adult lives until they die. This ability is prominent because sperm cells cannot maintain their fertilization ability long after ejaculation in animals; however, the cellular mechanisms remain unclear. Sperm cells are maintained in the female sperm storage organ, the spermatheca, which supplies a suitable environment for sperm cells. To reveal the molecular basis of the long-term sperm storage mechanisms in ant queens, protein profiles enriched in the spermathecal fluid relative to the hemolymph were identified in Lasius japonicus using mass spectrometry-based proteomics. Proteins related to the extracellular matrix, antioxidant, metabolic pathways, proteases, and with uncharacterized functions were enriched in the spermathecal fluid relative to the hemolymph. These enriched proteins were shared with highly expressed genes previously detected by transcriptome analyses of the spermatheca in queens of Crematogaster osakensis belonging to a different subfamily than L. japonicus. It is considered that the ability for long-term sperm storage has evolved in the early ant lineage; therefore, the common proteins identified in the two ant species are crucial for this ability.

zoology↗

bioRxiv2022

Near-anoxia induces immobilisation and sustains viability of sperm in ant queens: Novel insights into mechanisms of prolonged sperm storage

Insect females store sperm in a spermatheca after copulation for some duration to use it later for fertilisation. At the beginning of their adult lives, ant queens can preserve numerous viable sperm cells from copulation for over ten years. However, the key factors influencing long-term sperm storage have not been identified. Here we show that the spermathecal environment is near anoxic, which induces sperm immobilisation. Furthermore, mitochondrial respiratory inhibitors suppress sperm motility, suggesting that sperm immobilisation may be caused by a shortage of ATP generated from only glycolysis under near anoxic condition. Sperm immobilisation is not induced by acidification via glycolytic metabolism because the spermathecal fluid is not acidic. Finally, we show that artificial anoxic conditions rather than aerobic conditions sustain viable sperm cells. Therefore, near-anoxia is a key factor influencing long-term sperm storage in ant queens. The viability of sperm cells under artificial anoxia, however, is lower than of those dissected immediately from queens. Moreover, the immotile sperm cells under more than 4 h of anoxia do not begin swimming after aerobic exposure, unlike those that were in anoxic conditions for less than 2 h. This indicates that factors other than anoxia are also necessary for long-term sperm preservation.

zoology↗

bioRxiv2021

Morphology of immatures of the thelytokous ant, Monomorium triviale Wheeler (Formicidae: Myrmicinae: Solenopsidini) with descriptions of the larval caste dimorphism

The ant genus Monomorium is one of the most species-rich but taxonomically problematic groups in the hyperdiverse subfamily Myrmicinae. An East Asian species, M. triviale Wheeler, produces both reproductive queens and sterile workers via obligate thelytokous parthenogenesis. Here, we describe the immature forms of M. triviale based on light and scanning electron microscopy observations, with a note on the striking caste dimorphism in the last larval instar. The last-instar queen larvae were easily recognized by their large size, "aphaenogastroid" body shape, and rows of doorknob-like tubercles on the lateral and dorsal body surface. This type of queen-specific structure has not been found in ants in general, let alone congeneric species found in Japan. In stark contrast to the queen larvae, worker larvae showed a "pheidoloid" body shape and a body surface similar to other ants. The worker larvae were estimated to have three instars, consistent with previously described congeners. The pupae of both castes had no cocoon, a characteristic commonly described in other Myrmicinae species. In total, the developmental period from egg to adult worker averaged 59 days under 25{degrees}C. We discuss possible functions of the tubercles of queen larvae based on previous studies.

zoology↗

bioRxiv2020

Butyrate producing Clostridiales utilize distinct human milk oligosaccharides correlating to early colonization and prevalence in the human gut

The early life human gut microbiota exerts life-long health effects on the host, but the mechanisms underpinning its assembly remain elusive. Particularly, the early colonization of Clostridiales from the Roseburia-Eubacterium group, associated with protection from colorectal cancer, immune- and metabolic disorders is enigmatic. Here we unveil the growth of Roseburia and Eubacterium members on human milk oligosaccharides (HMOs) using an unprecedented catabolic apparatus. The described HMO pathways and additional glycan utilization loci confer co-growth with Akkermansia muciniphilia via cross-feeding and access to mucin O-glycans. Strikingly, both, HMO and xylooligosaccharide pathways, were active simultaneously attesting an adaptation to a mixed HMO-solid food diet. Analyses of 4599 Roseburia genomes underscored the preponderance of HMO pathways and highlighted different HMO utilization phylotypes. Our revelations provide a possible rationale for the early establishment and resilience of butyrate producing Clostridiales and expand the role of specific HMOs in the assembly of the early life microbiota.

microbiology↗