Biology subjects

Yaginuma, T.

Publications and source records attributed to Yaginuma, T..

3 recordsLinked to original sources

bioRxiv2025

Expression dynamics and functional characterization of the pigmented and non-diapausing egg gene (pnd) and pnd-2, responsible for the initiation of embryonic diapause in the silkworm, Bombyx mori

Diapause in insects is a developmental arrest that serves as an adaptation to severe environmental conditions. In the silkworm Bombyx mori, embryonic diapause in the next generation is maternally induced by the diapause hormone (DH). However, the downstream factors responsible for initiating diapause have remained unidentified. The pnd and pnd-2 mutants produce pigmented and non-diapausing eggs despite intact DH signaling, indicating that the pnd and pnd-2 genes act downstream as potential initiators of diapause. Here, we analyzed their expression dynamics and functions. Expression analyses showed that pnd was strongly upregulated in diapause-destined eggs in a DH-signal-dependent manner and was suppressed by HCl treatment that prevents diapause initiation. In contrast, pnd-2 exhibited a transient expression peak independent of DH-signal and was unaffected by HCl treatment. RNAi-mediated knockdown of either gene inhibited the diapause initiation, and injection of pnd mRNA into non-diapause-destined eggs induced a diapause-like state in embryos. These findings demonstrate that pnd and pnd-2 are required downstream of the DH-signal to initiate diapause, providing key insights into the molecular mechanism underlying embryonic diapause induction in B. mori. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/667111v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@7e9516org.highwire.dtl.DTLVardef@6dddc2org.highwire.dtl.DTLVardef@fa11baorg.highwire.dtl.DTLVardef@1a2054e_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2019

Acute feeding disorder after oral RNAi exposure results in efficient pest control

Selecting an appropriate target gene is critical to the success of feeding RNA interference (f-RNAi)-based pest control. Gene targets have been chosen based on their ability to induce lethality. However, lethality induction by f-RNAi is slow-acting and crop damage can progress during this time. Here, we show that f-RNAi of death-associated inhibitor of apoptosis protein 1 (diap1), but not two conventional targets vacuolar ATPase subunit A and E, induces acute feeding cessation in the solanaceous pest, Henosepilachna vigintioctopunctata during 24-48 hours. We also found that the feeding cessation by diap1 f-RNAi has species-specificity and occurs with only 1.6 ng dsRNA. Our results suggest that diap1 is an appropriate target in the context of rapid reduction of crop damage. We propose that acute feeding disorder should be assessed as a novel criterion for selecting appropriate target genes for RNAi-based pest control in addition to the conventional criterion based on lethality.

molecular biology↗

bioRxiv2019

Unique Cancer Motility Behaviors in Confined Spaces of Microgroove Topography with Acute Wall Angles

In recent years, many types of micro-engineered platform have been fabricated to investigate the influences of surrounding microenvironments on cell migration. Previous researches demonstrate that microgroove-based topographies can influence cell motilities of normal and cancerous cells differently. In this paper, the microgroove wall angle is altered from obtuse to acute angles and the resulting differences in the responses of normal and cancer cells are investigated to explore the geometrical characteristics that can efficiently distinguish normal and cancer cells. Interestingly, trends in cell motilities of normal and cancer cells as the wall angles are varied between 60-120{degrees} were different, and in particular, invasive cancer cells exhibit a unique, oscillatory migratory behavior. Results from the immunostaining of cell mechanotransduction components suggest that this difference stems from directional extension and adhesion behaviors of each cell type. In addition, the specific behaviors of invasive cancer cells are found to be dependent on the myosin II activity, and modulating the activity can revert cancerous behaviors to normal ones. These novel findings on the interactions of acute angle walls and cancer cell migration provide a new perspective on cancer metastasis and additional strategies via microstructure geometries for the manipulations of cell behaviors in microscale biodevices.\n\nStatement of SignificanceCancer metastasis is the leading cause of cancer patient deaths, and yet how the microstructures within the body affect this cell migration phenomenon is not well understood. In this paper, microdevices containing microgroove structures of varying geometries, in particular obtuse and acute angles, were utilized to monitor cell motilities of various cancer cells to understand the influences of the geometrical features of microstructures on cancer metastasis. Surprisingly, it was found that the acute angle geometries lowered the persistence of migration for cancer cells, which was a totally different response from non-cancerous cells. These new findings would enable the next-generation biodevices to analyze, separate and capture cancer cells, as well as shed light onto the underlying mechanisms of cancer metastasis.

cancer biology↗