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The uncontrollable migration of cancer cells is one of the reasons for the poor prognosis. The interaction between collagen and cellular processes is usually dominated by the full triple-helix structure of collagen. However, it remains to be explored how the collagen configuration affects the migration behaviors of cancer cells. Michigan cancer foundation-7 cells are chosen to study this relationship. Meanwhile, the grass carp is one of the representative fish species in Hubei and is virtually unaffected by zoonotic diseases. Therefore, grass carp-derived collagen is prepared and used to modulate the migration behaviors. The collagen sample is pretreated via several procedures including the hydrothermal process and EDC/NHS, respectively. The underlying mechanisms affecting migration behavior are explored by tuning the degree of denaturation, assembly states, and cross-linking conditions of collagen. Results demonstrate that moderate crosslinking and assembly contribute to the migration processes, while denaturation significantly suppresses migration. Of particular note is the positive correlation of F-actin expression levels with these phenomena. More importantly, the hydrophilic and hydrophobic properties of the collagen surface also affect the migration process. In summary, the study may provide insights to flexibly tune the migration behavior of cancer cells, which may be promising in inhibiting tumor metastasis. [ABSTRACT FROM AUTHOR]

Silent information regulator 2 (Sir2) proteins typically catalyze NAD+-dependent protein deacetylation. The recently identified bacterial Sir2 domain- containing protein, defense-associated sirtuin 2 (DSR2), recognizes the phage tail tube and depletes NAD+ to abort phage propagation, which is counteracted by the phage-encoded DSR anti-defense 1 (DSAD1), but their molecular mechanisms remain unclear. Here, we determine cryo-EM structures of inactive DSR2 in its apo form, DSR2–DSAD1 and DSR2–DSAD1–NAD+, as well as active DSR2–tube and DSR2–tube–NAD+ complexes. DSR2 forms a tetramer with its C-terminal sensor domains (CTDs) in two distinct conformations: CTDclosed or CTDopen. Monomeric, rather than oligomeric, tail tube proteins preferentially bind to CTDclosed and activate Sir2 for NAD+ hydrolysis. DSAD1 binding to CTDopen allosterically inhibits tube binding and tube-mediated DSR2 activation. Our findings provide mechanistic insight into DSR2 assembly, tube-mediated DSR2 activation, and DSAD1-mediated inhibition and NAD+ substrate catalysis in bacterial DSR2 anti-phage defense systems. [ABSTRACT FROM AUTHOR]

Tomato leaf miner (Tuta absoluta) is a notoriously invasive pest that has spread from South America to over 110 countries worldwide and poses a significant threat to the global tomato industry. Adverse effects associated with the overuse of chemical insecticides have prompted researchers to seek ecologically-based management options, such as using secondary plants. However, research on the repellent plants of T. absoluta is missing. In this study, we assessed the potential of nine commonly reported repellent plants. Rosmarinus officinalis was found to exhibit a significant repellent effect against T. absoluta. We quantified the volatile organic compounds (VOCs) in R. officinalis, and further determined the repellent effects of the specific VOCs. The plant R. officinalis and the VOC eucalyptol delayed the developmental period of T. absoluta and decreased the egg-hatching rate. By running cage and greenhouse experiments, we confirmed that R. officinalis and eucalyptol reduced the damage caused by T. absoluta via antixenosis (i.e. reduced number of eggs laid). Our results showed the important function of R. officinalis and its VOCs in controlling T. absoluta, guiding the use of repellent plants as a key component of Integrated Pest Management packages. [ABSTRACT FROM AUTHOR]

Weathering has always been a concerned around the world, as the first and most important step in the global cycle of elements, which leads to the fractionation of isotopes on the scale of geological age. The Middle Ordovician Majiagou Formation in Daniudi area of the Ordos Basin had experienced weathering for >130 Myr. Through thin section observation, major and trace element analysis, carbon, oxygen, and magnesium isotopes composition analysis, the dolomitization modes and weathering of ancient dolomite in Daniudi area were analyzed in detail. The results showed that the Sabkha and brine-reflux dolomitization modes had developed, and the Mg isotopes in different layers of the karst crust were fractionated by various factors. The vertical vadose zone was affected by weathering, the Mg isotope of dolomite (δ26Mgdol) showed a downward decreasing trend; the horizontal underflow zone was controlled by diagenesis and formation fluid, β26Mgdol showed a vertical invariance and negative; the main reason for Mg isotope fractionation in the deep slow-flow zone was the brine-reflux dolomitization mode during early burial period, which showed a vertical downward increase. Finally, the Mg isotope characteristic data of the ancient weathering crust were provided and the process of Mg isotope fractionation in the karst crust was explained. [ABSTRACT FROM AUTHOR]

Reconstructing paleoenvironments has long been considered a vital component for understanding the development and evolution of carbonate reservoirs. The Middle Ordovician Period is considered the archetypical greenhouse interval, and also a critical period in biological evolution. The Middle Darriwilian isotope carbon excursion has been observed in many areas of the world and may be related to the biological explosions caused by decreases in the temperature. The thick carbonate rocks in the fifth member of the Middle Ordovician Majiagou Formation in the Dingbei area of the Ordos Basin were chosen as an example, based on the concentration of major, trace and rare earth elements as well as C, O and Sr isotopic analyses, the paleoenvironment was reconstructed. And its impact on natural gas exploration was analyzed. The results show that the seawater paleotemperature was 29 °C, suboxicanoxic paleoredox conditions were observed, and the seawater paleosalinity was high. A large number of plankton in the biological explosion caused a rapid increase in the total organic carbon in carbonate rocks, which provided natural gas as supplemental source rocks. Affected by early meteoric water, the dissolution of gypsum laid the foundation for high-quality reservoirs, and the residual gypsum also further preserved natural gas. This study provides new data for the paleoenvironment and a theoretical basis for further natural gas exploration. [ABSTRACT FROM AUTHOR]

The myophage possesses a contractile tail that penetrates its host cell envelope. Except for investigations on the bacteriophage T4 with a rather complicated structure, the assembly pattern and tail contraction mechanism of myophage remain largely unknown. Here, we present the fine structure of a freshwater Myoviridae cyanophage Pam3, which has an icosahedral capsid of ~680 Å in diameter, connected via a three-section neck to an 840-Å-long contractile tail, ending with a three-module baseplate composed of only six protein components. This simplified baseplate consists of a central hub-spike surrounded by six wedge heterotriplexes, to which twelve tail fibers are covalently attached via disulfide bonds in alternating upward and downward configurations. In vitro reduction assays revealed a putative redox-dependent mechanism of baseplate assembly and tail sheath contraction. These findings establish a minimal myophage that might become a user-friendly chassis phage in synthetic biology. [ABSTRACT FROM AUTHOR]

Background: Exosomal proteins from cancer cells are becoming new biomarkers for cancer monitoring and efficacy evaluation. However, their biological function and molecular mechanism underlying tumor metastasis are largely unknown. Methods: Bioinformatic methods such as bulk gene expression analysis, single-cell RNA sequencing data analysis, and gene set enrichment analysis were employed to identify metastasis-associated proteins. The in vitro and in vivo experiments were used to investigate the function of RAB13 in HCC metastasis. Results: We identified RAB13 as one of the critical regulators of metastasis in HCC-derived exosomes for the first time. In vitro, the invasiveness of HCC cell lines could be attenuated by RAB13 silence. In vivo, tumor size and proportion of high-grade lung metastatic nodule could be reduced in the mice with orthotopic transplantation of tumors and intravenously injected with exosomes derived from MHCC97H cell with RAB13 silence (si-RAB13-Exo), as compared with those without RAB13 silence (si-NC-Exo). Moreover, in si-RAB13-Exo group, circulating tumor cell counts were decreased at the third, fourth, and fifth weeks after orthotopic transplantation of tumors, and MMP2 (matrix metalloproteinase 2)/TIMP2 (tissue inhibitor of metalloproteinases 2) ratio was also significantly decreased. In addition, RAB13 expression was also associated with VEGF levels, microvessel density, and tube formation of vascular endothelial cells by both in vitro and in vivo models, indicating that RAB13 was associated with angiogenesis in HCC. Conclusions: We have demonstrated exosomal RAB13 as a potential regulator of metastasis for HCC by in silico, in vitro, and in vivo methods, which greatly improve our understanding of the functional impact of exosomal proteins on HCC metastasis. [ABSTRACT FROM AUTHOR]

Omega-3 polyunsaturated fatty acids (PUFAs) can play important roles in maintaining mental health and resistance to stress, and omega-3 PUFAs supplementation can display beneficial effects on both the prevention and treatment of depressive disorders. Although the underlying mechanisms are still unclear, accumulated evidence indicates that omega-3 PUFAs can exhibit pleiotropic effects on the neural structure and function. Thus, they play fundamental roles in brain activities involved in the mood regulation. Since depressive symptoms have been assumed to be of central origin, this review aims to summarize the recently published studies to identify the potential neurobiological mechanisms underlying the anti-depressant effects of omega-3 PUFAs. These include that of (1) anti-neuroinflammatory; (2) hypothalamus-pituitary-adrenal (HPA) axis; (3) anti-oxidative stress; (4) anti-neurodegeneration; (5) neuroplasticity and synaptic plasticity; and (6) modulation of neurotransmitter systems. Despite many lines of evidence have hinted that these mechanisms may co-exist and work in concert to produce anti-depressive effects, the potentially multiple sites of action of omega-3 PUFAs need to be fully established.We also discussed the limitations of current studies and suggest future directions for preclinical and translational research in this field. [ABSTRACT FROM AUTHOR]