Hydraulic properties and drought response of a tropical bamboo (Cephalostachyum pergracile)

Bamboo plants are an essential component of tropical ecosystems,yet their vulnerability to climate extremes,such as drought,is poorly understood due to limited knowledge of their hydraulic properties.Cephalostachyum pergracile,a commonly used tropical bamboo species,exhibited a substantially higher mortality rate than other co-occurring bamboos during a severe drought event in 2019,but the underlying mechanisms remain unclear.This study investigated the leaf and stem hydraulic traits related to drought responses,including leaf-stem embolism resistance(P50leaf;P50stem) estimated using optical and X-ray microtomography methods,leaf pressure-volume and water-releasing curves.Additionally,we investigated the seasonal water potentials,native embolism level(PLC) and xylem water source using stable isotope.We found that C.pergracile exhibited strong resistance to embolism,showing low P50leaf,P50stem,and turgor loss point,despite its rapid leaf water loss.Interestingly,its leaves displayed greater resistance to embolism than its stem,suggesting a lack of effective hydraulic vulnerability segmentation(HVS) to protect the stem from excessive xylem tension.During the dry season,approximately 49% of the water was absorbed from the upper 20-cm-deep soil layer.Consequently,significant diurnal variation in leaf water potentials and an increase in midday PLC from 5.87±2.33% in the wet season to 12.87±4.09%in the dry season were observed.In summary,this study demonstrated that the rapid leaf water loss,high reliance on surface water,and a lack of effective HVS in C.pergracile accelerated water depletion and increased xylem embolism even in the typical dry season,which may explain its high mortality rate during extreme drought events in 2019.

Reference Gene Selection for Normalization of PCR Analysis in Chicken Embryo Fibroblast Infected with H5N1 AIV

Chicken embryo fibroblasts (CEFs) are among the most commonly used cells for the study of interactions between chicken hosts and H5N1 avian influenza virus (AIV).In this study,the expression of eleven housekeeping genes typically used for the normalization of quantitative real-time PCR (QPCR) analysis in mammals were compared in CEFs infected with H5N1 AIV to determine the most reliable reference genes in this system.CEFs cultured from 10-day-old SPF chicken embryos were infected with 100 TCID50 of H5N1 AIV and harvested at 3,12,24 and 30 hours post-infection.The expression levels of the eleven reference genes in infected and uninfected CEFs were determined by real-time PCR.Based on expression stability and expression levels,our data suggest that the ribosomal protein L4 (RPL4) and tyrosine 3-monooxygenase tryptophan 5-monooxygenase activation protein zeta polypeptide (YWHAZ) are the best reference genes to use in the study of host cell response to H5N1 AIV infection.However,for the study of replication levels of H5N1 AIV in CEFs,the β-actin gene (ACTB) and the ribosomal protein L4 (RPL4) gene are the best references.

Phycocyanobilin accelerates liver regeneration and reduces mortality rate in carbon tetrachloride-induced liver injury mice

AIM: To investigate the hepatoprotective effects of phycocyanobilin(PCB) in reducing hepatic injury and accelerating hepatocyte proliferation following carbon tetrachloride(CCl4) treatment.METHODS: C57BL/6 mice were orally administered PCB 100 mg/kg for 4 d after CCl4 injection, and then the serum and liver tissue of the mice were collected at days 1, 2, 3, 5 and 7 after CCl4 treatment. A series of evaluations were performed to identify the curative effects on liver injury and recovery. Aspartate aminotransferase(AST), alanine aminotransferase(ALT), albumin and superoxide dismutase(SOD) were detected to indirectly assess the anti-inflammatory effects of PCB. Meanwhile, we detected the expressions of hepatocyte growth factor, transforming growth factor alpha(TGF-α), TGF-β, tumor necrosis factor-alpha(TNF-α) and interleukin-6(IL-6), the factors which are associated with inflammation and liver regeneration. The protein expressions of proliferating cell nuclear antigen(PCNA), TNF-α and cytochrome C were detected by western blot. Furthermore, the survivalrates were analyzed of mice which were administered a lethal dose of CCl4(2.6 mg/kg)with or without PCB.RESULTS:In our research,PCB showed a strongly anti-inflammatory effect on CCl4-induced liver injury in mice.The ALT was significantly decreased after CCl4 treatment from day 1(P<0.01)and the AST was significantly decreased from day 2(P<0.001).Both albumin and liver SOD were increased from day2(P<0.001 and P<0.01),but serum SOD levels did not show a significant increase(P>0.05).PCB protected the structure of liver from the injury by CCl4.TUNEL assay showed that PCB dramatically reduced the number of apoptotic cells after CCl4 treatment compared to the control(101.0±25.4 vs 25.7±6.4,P<0.01).The result of western blotting showed that PCB could increase PCNA expression,decrease TNF-αand cytochrome C expression.Furthermore,data shows that PCB could improve the survival rate of acute liver failure(ALF)mice which were injected with a lethal dose of CCl4(60.0%vs 20.0%).CONCLUSION:Our study indicated that PCB could be an ideal candidate for reversing acute liver injury or ALF.

Dihydromyricetin inhibits migration and invasion of hepatoma cells through regulation of MMP-9 expression

AIM:To investigate the effects of dihydromyricetin(DHM)on the migration and invasion of human hepatic cancer cells.METHODS:The hepatoma cell lines SK-Hep-1 and MHCC97L were used in this study.The cells were cultured in RPIM-1640 medium supplemented with 10%fetal bovine serum at 37℃in a humidified 5%CO2incubator.DHM was dissolved in dimethyl sulfoxide and diluted to various concentrations in medium before applying to cells.MTT assays were performed to measure the viability of the cells after DHM treatment.Wound healing and Boyden transwell assays were used to assess cancer cell motility.The invasive capacity of cancer cells was measured using Matrigel-coated transwell chambers.Matrix metalloproteinase(MMP)-2/9 activity was examined by fluorescence analysis.Western blot was carried out to analyze the expression of MMP-2,MMP-9,p-38,JNK,ERK1/2 and PKC-δproteins.All data were analyzed by Student’s t tests in GraphPad prism 5.0software and are presented as mean±SD.RESULTS:DHM was found to strongly inhibit the migration of the hepatoma cell lines SK-Hep-1(without DHM,24 h:120±8μmol/L vs 100μmol/L DHM,24h:65±10μmol/L,P<0.001)and MHCC97L(without DHM,24 h:126±7μmol/L vs 100μmol/L DHM,24h:74±6μmol/L,P<0.001).The invasive capacity of the cells was reduced by DHM treatment(SK-Hep-1cells without DHM,24 h:67±4μmol/L vs 100μmol/L DHM,24 h:9±3μmol/L,P<0.001;MHCC97L cells without DHM,24 h:117±8μmol/L vs 100μmol/L DHM,24 h:45±2μmol/L,P<0.001).MMP2/9 activity was also inhibited by DHM exposure(SK-Hep-1 cells without DHM,24 h:600±26μmol/L vs 100μmol/L DHM,24 h:100±6μmol/L,P<0.001;MHCC97L cells without DHM,24 h:504±32μmol/L vs 100μmol/L DHM 24 h:156±10μmol/L,P<0.001).Western blot analysis showed that DHM decreased the expression level of MMP-9 but had little effect on MMP-2.Further investigation indicated that DHM markedly reduced the phosphorylation levels of p38,ERK1/2 and JNK in a concentration-dependent manner but had no impact on the total protein levels.In addition,PKC-δprotein,a key protein in the regulation of MMP family protein expression,was up-regulated with DHM treatment.CONCLUSION:These findings demonstrate that DHM inhibits the migration and invasion of hepatoma cells and may serve as a potential candidate agent for the prevention of HCC metastasis.

Dihydromyricetin-mediated inhibition of the Notch1 pathway induces apoptosis in QGY7701 and Hep G2 hepatoma cells

AIM To investigate whether Dihydromyricetin(DHM) inhibits cell proliferation and promotes apoptosis by downregulating Notch1 expression.METHODS The correlation between Notch1 and Hes1(a Notch1 target molecule) expression in hepatoma samples was confirmed by q RT-PCR. In addition, MTT assays, flow cytometry and TUNEL analysis showed that DHM possessed strong anti-tumor properties, evidenced not only by reduced cell proliferation but also by enhanced apoptosis in QGY7701 and Hep G2 hepatocellular carcinoma(HCC) cells. The expressions of Notch1, Hes1, Bcl-2 and Bax were determined by Western blot.RESULTS Among the tested samples(n = 64), the expression levels of Notch1(75% of patients) and Hes1(79.7% of patients) m RNA in tumor tissues were higher than in the normal liver tissues. There was a negative correlation between the expression of Notch1 and the degree of differentiation and positively correlated with the Alpha Fetal Protein concentration. The viability of HCC cells treated with DHM was significantly inhibited in a dose and time-dependent manner. Apoptosis was induced in Hep G2 and QGY7701 cell lines following 24 h of DHM treatment. After treatment with DHM, the protein expression of Notch1 was downregulated, the apoptosis-related protein Bax was upregulated and Bcl2 was downregulated. Notch1 si RNA further enhanced the anti-tumor properties of DHM. CONCLUSION Notch1 is involved in the development of HCC and DHM inhibits cell proliferation and promotes apoptosis by down-regulating the expression of Notch1.