Diversity and dynamics of endosymbionts in a single population of sweet potato weevil, Cylas formicarius (Coleoptera: Brentidae): a preliminary study.

Endosymbionts live symbiotically with insect hosts and play important roles in the evolution, growth, development, reproduction, and environmental fitness of hosts. Weevils are one of the most abundant insect groups that can be infected by various endosymbionts, such as Sodalis, Nardonella, and Wolbachia. The sweet potato weevil, Cylas formicarius (Coleoptera: Brentidae), is a notorious pest in sweet potato (Ipomoea batatas L.) cultivation. Currently, little is known about the presence of endosymbionts in C. formicarius. Herein, we assessed the endosymbiont load of a single geographic population of C. formicarius. The results showed that Nardonella and Rickettsia could infect C. formicarius at different rates, which also varied according to the developmental stages of C. formicarius. The relative titer of Nardonella was significantly related to C. formicarius developmental stages. The Nardonella-infecting sweet potato weevils were most closely related to the Nardonella in Sphenophorus levis (Coleoptera, Curculionidae). The Rickettsia be identified in bellii group. These results preliminarily revealed the endosymbionts in C. formicarius and helped to explore the diversity of endosymbionts in weevils and uncover the physiological roles of endosymbionts in weevils.

Substrates with patterned topography reveal metastasis of human cancer cells.

In this study, we aimed at studying the effects of engineered and patterned substrates on the migration characteristics of mammalian cancer cell lines. On the shallow topographical patterns, cells from different histological origins showed different migration speed and directionality. We also observed that cells from the same origin showed distinctive behaviour, suggesting these substrate topographies could distinguish cancer subtypes. To eliminate the influence of genetic background, we examined two isogenic subpopulations of ovarian cancer cell lines for their different metastatic activities. While these cell lines showed indistinguishable migration characteristics on a flat substrate, their motilities on the patterned substrates were highly different, suggesting that cancer cells' motilities on these substrates varied in a metastasis-dependent manner. While cells with different metastatic activities showed similar morphology and focal adhesion distribution on flat surface, vinculin aggregated into single cytoplasmic foci in metastatic cells cultured on the engineered substrates. This implies that the topographical patterns on the substrates induced vinculin redistribution in cancer cells with a higher invasive activity. The fabricated platforms with topographical patterns offer a novel in vitro technique for metastasis assessment. Moreover, such platforms could potentially provide the opportunity to sort cells in different metastatic states using advanced pattern designs and features.

A Unidirectional Cell Switching Gate by Engineering Grating Length and Bending Angle.

On a microgrooved substrate, cells migrate along the pattern, and at random positions, reverse their directions. Here, we demonstrate that these reversals can be controlled by introducing discontinuities to the pattern. On "V-shaped grating patterns", mouse osteogenic progenitor MC3T3-E1 cells reversed predominately at the bends and the ends. The patterns were engineered in a way that the combined effects of angle- and length-dependence could be examined in addition to their individual effects. Results show that when the bend was placed closer to one end, migration behaviour of cells depends on their direction of approach. At an obtuse bend (135°), more cells reversed when approaching from the long segment than from the short segment. But at an acute bend (45°), this relationship was reversed. Based on this anisotropic behaviour, the designed patterns effectively allowed cells to move in one direction but blocked migrations in the opposing direction. This study demonstrates that by the strategic placement of bends and ends on grating patterns, we can engineer effective unidirectional switching gates that can control the movement of adherent cells. The knowledge developed in this study could be utilised in future cell sorting or filtering platforms without the need for chemotaxis or microfluidic control.