The role of symbiotic fungi in the life cycle of Gastrodia elata Blume (Orchidaceae): a comprehensive review.

Gastrodia elata Blume, a fully mycoheterotrophic perennial plant of the family Orchidaceae, is a traditional Chinese herb with medicinal and edible value. Interestingly, G. elata requires symbiotic relationships with Mycena and Armillaria strains for seed germination and plant growth, respectively. However, there is no comprehensive summary of the symbiotic mechanism between fungi and G. elata. Here, the colonization and digestion of hyphae, the bidirectional exchange of nutrients, the adaptation of fungi and G. elata to symbiosis, and the role of microorganisms and secondary metabolites in the symbiotic relationship between fungi and G. elata are summarized. We comprehensively and deeply analyzed the mechanism of symbiosis between G. elata and fungi from three perspectives: morphology, nutrition, and molecules. The aim of this review was to enrich the understanding of the mutualistic symbiosis mechanisms between plants and fungi and lay a theoretical foundation for the ecological cultivation of G. elata.

Comprehensive Analysis of Prognostic Value and Immune Infiltration of MMP12 in Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a typical neoplastic disease and a frequent cause of death in China. The prognosis of most ESCC patients is still poor. Previous studies demonstrated that MMP12 is involved in tumor metastasis. However, its clinical significance and association with cancer immunity remained largely unclear. In this study, we first analyzed the expressing pattern of MMPs in ESCC from TCGA datasets and found that several MMPs expression was distinctly increased in ESCC. However, only MMP12 expression was associated with five-year survival of ESCC patients. Then, we focused on MMP12 and found its high expression was positively related to advanced clinical stages of ESCC specimens. KEGG assays revealed MMP12 may influence the activity of several tumor-related pathways, such as the Toll-like receptor signaling pathway, TNF signaling pathway, and IL-17 signaling pathway. Then, we sought to determine whether MMP12 expressions were related to immune cell infiltration in ESCC. We observed that increased MMP12 levels were positively associated with the infiltration levels of mast cells activated and macrophages M0. However, eosinophils, B cells naïve, and mast cells resting exhibited an opposite result. Finally, we showed that knockdown of MMP12 suppressed the proliferation of ESCC cells. Overall, our findings proved that high expression of MMP12 may be a novel and valuable prognostic factor in ESCC.

Photoinactivation of the oxygen-evolving complex regulates the photosynthetic strategy of the seagrass Zostera marina.

Zostera marina, a widespread seagrass, evolved from a freshwater ancestor of terrestrial monocots and successfully transitioned into a completely submerged seagrass. We found that its oxygen-evolving complex (OEC) was partially inactivated in response to light exposure, as evidenced by both the increment of the relative variable fluorescence at the K-step and the downregulation of the OEC genes and proteins. This photosynthetic regulation was further addressed at both proteome and physiology levels by an in vivo study. The unchanged content of the ΔpH sensor PsbS protein and the non-photochemical quenching induction dynamics, described by a single exponential function, verified the absence of the fast qE component. Contents and activities of chlororespiration, Mehler reaction, malic acid synthesis, and photorespiration key enzymes were not upregulated, suggesting that alternative electron flows remained unactivated. Furthermore, neither significant production of singlet oxygen nor increment of total antioxidative capacity indicated that reactive oxygen species were not produced during light exposure. In summary, these low electron consumptions may allow Z. marina to efficiently use the limited electrons caused by partial OEC photoinactivation to maintain a normal carbon assimilation level.

Interaction of high seawater temperature and light intensity on photosynthetic electron transport of eelgrass (Zostera marina L.).

The interaction of widely recognized causes of eelgrass decline (high seawater temperature and limited light intensity) on photosynthetic electron transport was investigated via chlorophyll fluorescence technique. High seawater temperature combined light intensity significantly increasing the relative maximum electron transport rate (rETRmax); at critical temperature of 30 °C, the rETRmax increased with the enhancement of light intensity, indicating the elevation of overall photosynthetic performance. Based on the magnitude of effect size (η2), light intensity was the predominant factor affecting the performance index (PIABS), indicating that photosystem II (PSII) was sensitive to light intensity. Moreover, the donor side was severely damaged as evidenced by the higher decrease amplitude of fast component and its subsequent incomplete recovery. The reaction center exhibited limited flexibility due to the slight decrease amplitude in maximum photochemical quantum yield. In contrast with PSII, photosystem I (PSI) was more sensitive to high seawater temperature, based on the magnitude of η2 derived from the maximal decrease in slope. High seawater temperature significantly increased PSI activity, plastoquinol reoxidation capacity, and probability for electron transfer to final PSI electron acceptors. Moreover, it combined elevated light intensity significantly stimulated the activity of cyclic electron flow (CEF) around PSI. Higher activity of both PSI and CEF contributed to balancing the linear electron transport via alleviating the over-reduction of the plastoquinone pool, exhibiting flexible regulation of photosynthetic electron transport at critical temperature. Therefore, limited light intensity decreased the tolerance of eelgrass to critical temperature, which might be a factor contributing factor in the observed decline.

Seasonal dynamics of photosynthetic activity in the representive brown macroalgae Sagrassum thunbergii (Sargassaceae Phaeophyta).

The present study evaluates the seasonal photosynthetic performances of Sargassum thunbergii via chlorophyll fluorescence technique. During summer and early winter, no significant change was observed in maximum photochemical efficiency (Fv/Fm), and performance index (PIabs). During late winter and early spring, Fv/Fm, and PIabs decreased significantly, implying that S. thunbergii photosystem II (PSII) suffered apparent photoinhibition. Subsequently, PSII gradually recovered during late spring and summer, as evidenced by an increase of both parameters. Throughout the year, the maximum decrease in the slope of MR/MR0 maintained low values indicated that photosystem I (PSI) was incative, the initial rate of P700+ re-reduction maintained low value indicated that cyclic electron transport (CET) were inactive; nevertheless, a seasonal down-regulation of both PSI and CET during late winter and early spring could be detected. The weak performance of PSI and CET can potentially limit the flexibility in response to winter stress and result in a delayed recovery of PSII. In conclusion, the seasonal variability of S. thunbergii photosynthetic activity was characterized by three periods: active state, down-regulation and restoration. The rapid growth during early spring was accompanied by weak photosynthetic performance, indicating that the carbohydrates consumed during this period were derived from previously stored starch.

Light intensity dependent photosynthetic electron transport in eelgrass (Zostera marina L.).

Responses of electron transport to three levels of irradiation (20, 200, and 1200 µmol photons m-2 s-1 PAR; exposures called LL, ML and HL, respectively) were investigated in eelgrass (Zostera marina L.) utilizing the chlorophyll a fluorescence technique. Exposure to ML and HL reduced the maximum quantum yield of photosystem II (PSII) (Fv/Fm) and the maximum slope decrease of MR/MRO (VPSI), indicating the occurrence of photoinhibition of both PSII and photosystem I (PSI). A comparatively slow recovery rate of Fv/Fm due to longer half-life recovery time of PSII and 40% lower descending amplitude compared to other higher plants implied the poor resilience of the PSII. Comparatively, PSI demonstrated high resilience and cyclic electron transport (CEF) around PSI maintained high activity. With sustained exposure, the amplitudes of the kinetic components (L1 and L2), the probability of electron transfer from PSII to plastoquinone pool (ψET2o), and the connectivity among PSII units decreased, accompanied by an enhancement of energy dissipation. Principle component analysis revealed that both VPSI and Fv/Fm contributed to the same component, which was consistent with high connectivity between PSII and PSI, suggesting close coordination between both photosystems. Such coordination was likely beneficial for the adaption of high light. Exposure to LL significantly increased the activity of both PSI and CEF, which could lead to increased light harvesting. Moreover, smooth electron transport as indicated by the enhancement of L1, L2, ψET2o and the probability of electron transport to the final PSI acceptor sides, could contribute to an increase in light utilization efficiency.

The alternation between PSII and PSI in ivy (Hedera nepalensis) demonstrated by in vivo chlorophyll a fluorescence and modulated 820 nm reflection.

To examine the coordination between photosystem II (PSII) and photosystem I (PSI) in response to varying environmental conditions, both diurnal fluctuations and seasonal variability of photosynthetic electron transport activity in ivy (Hedera nepalensis, Araliaceae) were investigated: by measuring prompt fluorescence, delayed fluorescence (DF) and modulated reflection of 820 nm light (MR). During diurnal fluctuations, the PSII electron donor side was damaged, as evidenced by decreases of the fast amplitude of DF decay kinetics at I1, although there was no significant change in relative variable fluorescence at K-step to amplitude of FJ - Fo. Decreases in the maximum photochemical efficiency (i.e., PSII photoinactivation) were accompanied by an increased maximum decrease in the slope of MR/MRo (i.e., PSI photoactivation). Subsequently, PSII recovery and PSI relaxation occurred in the afternoon. Throughout the season, alternations between PSII and PSI were also suggested by the down-regulation of PSII and the up-regulation of PSI from summer to winter. Significant negative linear correlations between the activity of PSII and PSI across both diurnal fluctuations and seasonal variability were verified by correlation analyses. In addition, PSI was active throughout the year, suggesting PSI is independent from high temperatures. High PSI activity may maintain the functional integrity of the photosynthetic apparatus in overwintering ivy. The alternation between PSII and PSI activity may regulate the distribution of excitation energy between the two photosystems and balance the redox state of the electron transport change, thereby enabling ivy to respond to varying environmental conditions.

Autophagy-associated targeting pathways of natural products during cancer treatment.

It is well known that conventional chemotherapy and radiation therapy can result in toxicity to both normal cells and tumor cells, which causes limitations in the application of these therapeutic strategies for cancer control. Novel and effective therapeutic strategies for cancers with no or low toxicity for normal cells are a high priority. Therefore, natural products with anticancer activity have gained more and more attention due to their favorable safety and efficacy profiles. Pre-clinical and clinical studies have demonstrated that several representative natural compounds such as resveratrol, epigallocatechin-3-gallate, curcumin, allicin and ginsenosides have obvious anticancer potential. In this article, we summarize autophagy-associated targeting pathways of such natural products for inducing the death of cancer cells, and discuss the core autophagic pathways involved in cancer treatments. Recent advances in the discovery, evaluation and exploitation of natural compounds as therapeutic agents for cancers will provide references and support in pre-clinical and clinical application of novel natural drugs for the treatment of primary and metastatic tumors in the future.

[Detecting nicotine and its metabolite cotinine in human hair with capillary gas chromatography].

OBJECTIVE: To develop a rapid method for determination of nicotine and its metabolite cotinine in human hair with capillary gas chromatography with flame ionization detector. METHODS: The hair sample was digested by 1.5 mol/L sodium hydroxide solution. The nicotine and cotinine in the hair sample were extracted with a mixed solvent of dichloromethane-methanol (3:1). Aliquot of the extraction solution was vaporized with nitrogen flow and then methanol was added to dissolve the analysts. The analysts were tested with capillary gas chromatography. RESULTS: The detection limits (signal to noise ratio of 3:1) were 4.3 ng/mL for nicotine and 10 ng/mL for cotinine, respectively. The spiked recoveries were 90.33%-113.1% for nicotine with relative standard deviation (RSD) of 2.1%-7.0% and 92.92%-117.4% for cotinine with relative standard deviation (RSD) of 4.4%-8.9%, respectively. CONCLUSION: The proposed method is sensitive, simple, easy and rapid. It can be easily extended to large scale applications in tobacco epidemiology studies.

[Postaurical injection of compound betamethasone to treat the intractable low-frequency sensorineural hearing loss].

OBJECTIVE: To discuss the treatment of compound betamethasone injection in cases with the intractable low-frequency sensorineural hearing loss (LFSNHL). METHODS: Compound betamethasone injection 1 ml had been injected postaural only once to 23 cases with the unilateral LFSNHL, then observe the effect and follow-up at least 6 months. At the same time, the same therapy used to 4 cases with the binaural LFSNHL. The control group gave Merislon and Sibelium peroral for 2 weeks to 18 cases with the unilateral LFSNHL. RESULTS: In unilateral LFSNHL group, twelve cases recovered, 7 cases had the hearing improved and 4 cases were ineffective in 23 cases. The efficiency was 82.6%. 2 cases (2 ears) showed hearing falling at low-frequency after 2-3 months. Others didn't recur after 6 months. 1 case showed low-grade skin atrophy at the local injection part. No other side-effects showed. In 4 binaural cases, 2 cases in effect and the others had no effect, and the former recurred after 1-2 months. In control group, 1 week after the end of therapy, 3 cases (3 ears) recovered, 1 case (1 ear) recovered 2 weeks later after the end of therapy, and the 4 cases didn't recur after 2 months. The other 14 cases were ineffective. CONCLUSIONS: Compound betamethasone injection postaural treated intractable LFSNHL effectively, but no obvious efficiency to cases with the binaural LFSNHL. May be these cases have some relationship with autoimmune inner ear disease (AIED).

Metabolism of Oxidized High Density Lipoprotein-2(ox-HDL(2)) in Rat Hepatic Sinusoidal Cells.

Incubation of rat hepatic sinusoidal cells with FITC-HDL(2), FITC-ox-HDL(2) and [(3)H]CE-HDL(2)(rHDL(2)), ox-rHDL(2) showed that binding of FITC-HDL(2) to the cells was competitive to ox-HDL(2), but not to HDL(2). The cell-endocytic fluorescence strength (FS) of FITC-HDL(2) and radioactivity of ox-rHDL(2) were 45.5% of that of FITC-HDL(2) and 61.4% of that of rHDL(2), respectively. Endocytic FS and radioactivity were mainly in TCA-precipitable and supernatant part, respectively. The cell-released FS and radioactivity were 67.7% and 10.9% of the cell-endocytic FS and the radioactivity, respectively, and both of them were mainly TCA-precipitable. These results suggest that: (1) There is probably an ox-HDL receptor on the surface of rat hepatic sinusoidal cells, which is different from HDL receptor. (2) The metabolic behaviour of ox-rHDL(2) in the cells is similar to HDL(2). Both of them do not take a lysosomal pathway. Apoproteins and CE components dissociate from endocytic lipoprotein in the cells. After the cells have taken up most of CE, the residual CE recombines with apolipoprotein to form a lipoprotein and is released from the cells by retroendocytosis. (3) Oxidative modification of HDL(2) weakens its ability to cholesterol reverse transport.