Background: Cells are sensitive to changes in gravity, especially the cytoskeletal structures that determine cell morphology. The aim of this study was to assess the effects of simulated microgravity (SMG) on 3T3 cell morphology, as demonstrated by a characterization of the morphology of cells and nuclei, alterations of microfilaments and microtubules, and changes in cycle progression. Methods: 3T3 cells underwent induced SMG for 72 h with Gravite^®, while the control group was under 1G. Fluorescent staining was applied to estimate the morphology of cells and nuclei and the cytoskeleton distribution of 3T3 cells. Cell cycle progression was assessed by using the cell cycle app of the Cytell microscope, and Western blot was conducted to determine the expression of the major structural proteins and main cell cycle regulators. Results: The results show that SMG led to decreased nuclear intensity, nuclear area, and nuclear shape and increased cell diameter in 3T3 cells. The 3T3 cells in the SMG group appeared to have a flat form and diminished microvillus formation, while cells in the control group displayed an apical shape and abundant microvilli. The 3T3 cells under SMG exhibited microtubule distribution surrounding the nucleus, compared to the perinuclear accumulation in control cells. Irregular forms of the contractile ring and polar spindle were observed in 3T3 cells under SMG. The changes in cytoskeleton structure were caused by alterations in the expression of major cytoskeletal proteins, including β-actin and α-tubulin 3. Moreover, SMG induced 3T3 cells into the arrest phase by reducing main cell cycle related genes, which also affected the formation of cytoskeleton structures such as microfilaments and microtubules. Conclusions: These results reveal that SMG generated morphological changes in 3T3 cells by remodeling the cytoskeleton structure and downregulating major structural proteins and cell cycle regulators.

This study aimed to assess the recovery capability of Chang liver cells (CCL-13) following simulated microgravity (SMG) induction. CCL-13 cells were cultured under SMG conditions for 72 h, and control group cells were cultured under 1G conditions for an identical duration. Cells from the SMG and control groups were further cultured under 1G conditions and assessed after 24 h and 72 h intervals in the gravity recovery experiment. The WST1 results indicated that CCL-13 proliferation was more evident in the control group than in the SMG group after both the 24 h and 72 h intervals. The control group had a lower percentage of CCL-13 cells in the G0/G1 phase compared with the SMG group at both time points, and it exhibited a higher total percentage of cells in the S and G2/M phases. The control group exhibited elevated levels of cell-cycle-related proteins, including cyclin A, cyclin D, and cdk6, compared with the SMG group. The flow cytometry results revealed that the apoptotic rate in the control group was significantly lower than that in the SMG group at both the 24 h and 72 h time points. However, the apoptotic percentage in the SMG group at the 72-h mark was significantly lower than that at the 24-h mark. SMG reduces the viability and proliferation ability of CCL-13 cells. After a period of recovery and adaptation to normal gravity conditions (1G), the CCL-13 cells in the SMG group showed better signs of recovery after 72 h than after 24 h.

The grey-shanked douc langur (Pygathrix cinerea) is a recently described, critically endangered primate, endemic to Vietnam. In this study, we describe the Central Highland species’ complete mitochondrial genome (mitogenome—mtDNA). It is a circular molecule with a length of 16,541 base pairs (bp). The genome consists of 37 genes, consistent with those found in most other vertebrates, including 13 protein coding genes, 22 transfer RNAs, and two ribosomal RNAs. A comparison with the mitogenomes of more than 50 primates showed that the mitogenome of Vietnamese Central Highland Pygathrix cinerea has a conservative gene order. We identified 43 nucleotide differences when comparing this genome with a previously published mitogenome of Pygathrix cinerea. It is evident that there are distinct differences between the Pygathrix cinerea we are currently studying and other Pygathrix cinerea specimens. These differences are unlikely to be solely the result of sequencing errors, as the mitogenomes were generated using high-quality methods. The genetic divergence observed between the two Pygathrix cinerea mitogenomes implies the potential existence of at least two distinct lineages or forms of this primate species within its native range in Vietnam.