Stearic acid promotes lipid synthesis through CD36/Fyn/FAK/mTORC1 axis in bovine mammary epithelial cells.

Stearic acid (C18:0, SA) is a saturated long-chain fatty acid (LCFA) that has a prominent function in lactating dairy cows. It is obtained primarily from the diet and is stored in the form of triacylglycerol (TAG) molecules. The transmembrane glycoprotein cluster of differentiation 36 (CD36) is also known as fatty acid translocase, but whether SA promotes lipid synthesis through CD36 and FAK/mTORC1 signaling is unknown. In this study, we examined the function and mechanism of CD36-mediated SA-induced lipid synthesis in bovine mammary epithelial cells (BMECs). SA-enriched supplements enhanced lipid synthesis and the FAK/mTORC1 pathway in BMECs. SA-induced lipid synthesis, FAK/mTORC1 signaling, and the expression of lipogenic genes were impaired by anti-CD36 and the CD36-specific inhibitor SSO, whereas overexpression of CD36 effected the opposite results. Inhibition of FAK/mTORC1 by TAE226/Rapamycin attenuated SA-induced TAG synthesis, inactivated FAK/mTORC1 signaling, and downregulated the lipogenic genes PPARG, CD36, ACSL1, SCD, GPAT4, LIPIN1, and DGAT1 at the mRNA and protein levels in BMECs. By coimmunoprecipitation and yeast two-hybrid screen, CD36 interacted directly with Fyn but not Lyn, and Fyn bound directly to FAK; FAK also interacted directly with TSC2. CD36 linked FAK through Fyn, and FAK coupled mTORC1 through TSC2 to form the CD36/Fyn/FAK/mTORC1 signaling axis. Thus, stearic acid promotes lipogenesis through CD36 and Fyn/FAK/mTORC1 signaling in BMECs. Our findings provide novel insights into the underlying molecular mechanisms by which LCFA supplements promote lipid synthesis in BMECs.

Characterization of microbial community, ecological functions and antibiotic resistance in estuarine plastisphere.

The plastisphere is a new ecological niche. Compared to the surrounding water, microbial community composition associated with the plastisphere is known to differ with functional consequences. Here, this study characterized the bacterial and fungal communities associated with four types of plastisphere (polyethylene, polystyrene, polypropylene and polyvinyl chloride) in an estuarine habitat; assessed ecological functions including carbon, nitrogen, phosphorus and sulfur cycling, and determined the presence of antibiotic resistance genes (ARGs) and human pathogens. Stochastic processes dominated the community assembly of microorganisms on the plastisphere. Several functional genera related to nutrient cycling were enriched in the plastisphere. Compared to surrounding water and other plastisphere, the abundances of carbon, nitrogen and phosphorus cycling genes (cdaR, nosZ and chpy etc.) and ARGs (aadA2-1, cfa and catB8 etc.) were significantly increased in polyvinyl chloride plastisphere. In contrast, the polystyrene plastisphere was the preferred substrate for several pathogens being enriched with for example, Giardia lamblia 18S rRNA, Klebsiella pneumoniae phoE and Legionella spp. 23S rRNA. Overall, this study showed that different plastisphere had different effects on ecological functions and health risk in estuaries and emphasizes the importance of controlling plastic pollution in estuaries. Data from this study support global policy drivers that seek to reduce plastic pollution and offer insights into ecological functions in a new ecological niche of the Anthropocene.

Microbial functional traits in phyllosphere are more sensitive to anthropogenic disturbance than in soil.

Soil-plant microbiome plays a critical role in the regulation of terrestrial ecosystem function and service, including biogeochemical cycling and primary production. The lack of knowledge regarding the differences in microbial functional traits, i.e. the functional genes related to carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) cycles, between soil and plant microbiomes hampers our prediction of the terrestrial nutrient cycling processes under the pressure of anthropogenic disturbance. Herein, a quantitative microbial element cycling (QMEC) method and amplicon sequencing was employed to characterize CNPS cycling genes and microbial communities in soil and plant samples collected from peri-urban farmland with high anthropogenic disturbance and forest ecosystem with minimal disturbance. The soil-plant system harbored a diverse array of CNPS cycling genes, which were significantly more abundant in soil than in phyllosphere. The overall CNPS gene profiles in farmland samples was distinct from that of forest samples in both soil and plant phyllosphere. Farmland samples had a lower abundance of CNPS cycling genes than forest samples, indicating that intensive agricultural management practices may consequently compromise the biogeochemical cycling potential of nutrients. Significant positive correlations between the abundance of CNPS cycling genes and microbial diversity were observed in phyllosphere microbiome but not in soil, suggesting that the functional redundancy in soil microbiome may be higher than that of phyllosphere microbiome. Taken together, we provide experimental evidence for the substantial impacts of anthropogenic disturbance on CNPS cycling genes in the soil-plant system and necessitate future efforts to unravel the plant microbiome diversity and functionality under the pressure of global changes.

Partial replacement of inorganic phosphorus (P) by organic manure reshapes phosphate mobilizing bacterial community and promotes P bioavailability in a paddy soil.

The optimization of more sustainable fertilization practice to relieve phosphorus (P) resource scarcity and increase P fertilizer utilization, a better understanding of the regulatory roles of microbes in P mobilization is urgently required to reduce P input. The genes phoD and pqqC are responsible for regulating organic and inorganic P mobilization, respectively. Using high-throughput sequencing, the corresponding bacterial communities harbored by these genes were determined. We conducted a 4-year rice-rice-crop rotation to investigate the responses of phoD- and pqqC-harboring bacterial communities to the partial replacement of inorganic P fertilizer by organic manure with reduced P input. The results showed that a combination of organic and inorganic fertilization maintained high rice yield, and also produced a more complex and stable phosphate mobilizing bacterial community, which contributed to phosphatase activities more than their gene abundances in the model analysis. Compared with the conventional mineral fertilization, organic-inorganic fertilization with the reduced P input slightly increased pqqC gene abundance while significantly enhanced the abundance of phoD-harboring bacteria, especially the genera Bradyrhizobium and Methylobacterium known as potential organic P mineralizers which can maintain high rice production. Moreover, the increased pH was the most impactful factor for the phoD- and pqqC-harboring bacterial communities, by promoting microbial P turnover and greatly increasing bioavailable P pools (H2O-Pi and NaHCO3-Pi, NaOH-Pi) in this P-deficient paddy soil. Hence, our study demonstrated that the partial replacement of mineral P with organic manure could reshape the inorganic phosphate solubilizing and alkaline-phosphomonoesterase encoding bacterial communities towards more resilient and effective to the high P utilization and productivity over intense cultivation, providing insights into the potential of soil microbes in the efficient management of agricultural P fertilization.

Phosphorus fractions and oxygen isotope composition of inorganic phosphate in typical agricultural soils.

Phosphorus (P), despite being an essential nutrient element for plants growth in agricultural ecosystem, the low utilization rate of soil P and the environmental problems caused by soil P losses are serious. Therefore, scoping knowledge of the possible sources and utilization extent of soil P by microorganisms is very helpful for better understanding of promoting P utilization for sustainable agriculture. Oxygen isotope of phosphate technology is an effective tool to trace the sources of P. In this study, P contents and oxygen isotope composition of inorganic phosphate (δ18OP) of different pools (H2O-P, NaHCO3-P, NaOH-P, and HCl-P) in typical agricultural soil from Northeast China and Central China were analyzed and quantified. The results showed that fertilizer and land use were important factors influencing the contents of H2O-Pt and NaHCO3-Pt and the soil TP contents from different types of soils were greatly affected by soil weathering degree. The δ18OP of different P pools indicated that the difference in utilization extent of different P fractions by microorganisms and the δ18OP values of different P fractions could be due to accumulation of multiple factors. The results will provide effective information for further study on sources and effective utilization of different P fractions in soil.

A review of fMRI studies during visual emotive processing in major depressive disorder.

OBJECTIVES: This review synthesized literature on brain activity, indexed by functional magnetic resonance imaging (fMRI), during visual affective information processing in major depressive disorder (MDD). Activation was examined in regions consistently implicated in emotive processing, including the anterior cingulate cortex (ACC), prefrontal cortex (PFC), amygdala, thalamus/basal ganglia and hippocampus. We also reviewed the effects of antidepressant interventions on brain activity during emotive processing. METHODS: Sixty-four fMRI studies investigating neural activity during visual emotive information processing in MDD were included. RESULTS: Evidence indicates increased ventro-rostral ACC activity to emotive stimuli and perhaps decreased dorsal ACC activity in MDD. Findings are inconsistent for the PFC, though medial PFC hyperactivity tends to emerge to emotive information processing in the disorder. Depressed patients display increased amygdala activation to negative and arousing stimuli. MDD may also be associated with increased activity to negative, and decreased activity to positive, stimuli in basal ganglia/thalamic structures. Finally, there may be increased hippocampus activation during negative information processing. Typically, antidepressant interventions normalize these activation patterns. CONCLUSION: In general, depressed patients have increased activation to emotive, especially negative, visual stimuli in regions involved in affective processing, with the exception of certain PFC regions; this pattern tends to normalize with treatment.