Ginseng rusty root symptoms result from nitric oxide stress in soil.

Ginseng, from the roots of Panax ginseng C. A. Meyer, is a widely used herbal medicine in Asian countries, known for its excellent therapeutic properties. The growth of P. ginseng is depend on specific and strict environments, with a preference for wetness but intolerance for flooding. Under excessive soil moisture, some irregular rust-like substances are deposited on the root epidermis, causing ginseng rusty symptoms (GRS). This condition leads to a significant reduce in yield and quality, resulting in substantial economic loses. However, there is less knowledge on the cause of GRS and there are no effective treatments available for its treatment once it occurs. Unsuitable environments lead to the generation of large amounts of reactive oxygen species (ROS). We investigated the key indicators associated with the stress response during different physiological stages of GRS development. We observed a significant change in ROS level, MDA contents, antioxidant enzymes activities, and non-enzymatic antioxidants contents prior to the GRS. Through the analysis of soil features with an abundance of moisture, we further determined the source of ROS. The levels of nitrate reductase (NR) and nitric oxide synthase (NOS) activities in the inter-root soil of ginseng with GRS were significantly elevated compared to those of healthy ginseng. These enzymes boost nitric oxide (NO) levels, which in turn showed a favorable correlation with the GRS. The activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase first rose and then decreased as GRS developed. Excess soil moisture causes a decrease in oxygen levels. This activated NR and NOS in the soil, resulting in a production of excess NO. The NO then diffused into the ginseng root and triggered a burst of ROS through NADPH located on the cell membrane. Additionally, Fe2+ in soil was oxidized to red Fe3+, and finally led to GRS. This conclusion was also verified by the Sodium Nitroprusside (SNP), a precursor compound producing NO. The presence of NO from NR and NOS in water-saturated soil is responsible for the generation of ROS. Among these, NO is the main component that contribute to the occurrence of GRS.

Sodium nitroprusside improved the quality of Radix Saposhnikoviae through constructed physiological response under ecological stress.

The ecological significance of secondary metabolites is to improve the adaptive ability of plants. Secondary metabolites, usually medicinal ingredients, are triggered by unsuitable environment, thus the quality of medicinal materials under adversity being better. The quality of the cultivated was heavily declined due to its good conditions. Radix Saposhnikoviae, the dried root of Saposhnikovia divaricata (Turcz.) Schischk., is one of the most common botanicals in Asian countries, now basically comes from cultivation, resulting in the market price being only 1/10 to 1/3 of its wild counterpart, so improving the quality of cultivated Radix Saposhnikoviae is of urgency. Nitric oxide (NO) plays a crucial role in generating reactive oxygen species and modifying the secondary metabolism of plants. This study aims to enhance the quality of cultivated Radix Saposhnikoviae by supplementing exogenous NO. To achieve this, sodium nitroprusside (SNP) was utilized as an NO provider and applied to fresh roots of S. divaricata at concentrations of 0.03, 0.1, 0.5, and 1.0 mmol/L. This study measured parameters including the activities of antioxidant enzymes, secondary metabolite synthesis enzymes such as phenylalanine ammonia-lyase (PAL), 1-aminocyclopropane-1-carboxylic acid (ACC), and chalcone synthase (CHS), as well as the contents of NO, superoxide radicals (O2·-), hydrogen peroxide (H2O2), malondialdehyde (MDA), and four secondary metabolites. The quality of Radix Saposhnikoviae was evaluated with antipyretic, analgesic, anti-inflammatory effects, and inflammatory factors. As a result, the NO contents in the fresh roots were significantly increased under SNP, which led to a significant increase of O2·-, H2O2, and MDA. The activities of important antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), were found to increase as well, with their peak levels observed on the 2nd and 3rd days. PAL, ACC, and CHS activities were also significantly enhanced, resulting in the increased secondary metabolite contents of Radix saposhnikoviae in all groups, especially the 0.5 mmol/L SNP. The four active ingredients, prim-O-glucosylcimifugin, cimifugin, 4'-O-ß-D-glucosyl-5-O-methylvisamminol, and sec-O-glucosylhamaudol, increased by 88.3%,325.0%, 55.4%, and 283.8%, respectively, on the 3rd day. The pharmaceutical effects of Radix Saposhnikoviae under 0.5 mmol/L SNP were significantly enhanced. Exogenous SNP can induce the physiological response of S. divaricata under adverse conditions and significantly improve the quality of Radix Saposhnikoviae.

Characterization of a sigma class GST (GSTS6) required for cellular detoxification and embryogenesis in Tribolium castaneum.

The sigma glutathione S-transferases (GSTSs) are a class of cytosolic glutathione S transferases (GSTs) that play important roles in antioxidant defense in insects, but the mechanisms by which GSTSs contribute to antioxidant activity remain unclear. Here, we isolated a GSTS (GSTS6) from Tribolium castaneum and explored its function. Homology and phylogenetic analysis revealed that TcGSTS6 shared high identity with other evolutionarily conserved GSTSs. The recombinant TcGSTS6 protein had strong activity toward cumene hydroperoxide and 4-hydroxynonenal but low activity toward the universal substrate 1-chloro-2,4-dinitrobenzene. Exposure to various types of oxidative stress, including heat, cold, UV and pathogenic microbes, significantly induced TcGSTs6 expression, which indicates that it is involved in antioxidant defense. Knockdown TcGSTs6 by using RNA interference (RNAi) caused reduced antioxidant capacity, which was accomplished by cooperating with other antioxidant genes. Moreover, treatment with various insecticides such as phoxim, lambda-cyhalothrin, dichlorvos and carbofuran revealed that TcGSTS6 plays an important role in insecticide detoxification. The RNAi results showed that TcGSTS6 is essential for embryogenesis in T. castaneum. Our study elucidates the mechanism by which a GSTS contributes to antioxidant activity and enhances our understanding of the functional diversity of GSTSs in insects.

Characterization and functional analysis of hsp18.3 gene in the red flour beetle, Tribolium castaneum.

Small heat shock proteins (sHSPs) are diverse and mainly function as molecular chaperones to protect organisms and cells from various stresses. In this study, hsp18.3, one Tribolium castaneum species-specific shsp, has been identified. Quantitative real-time polymerase chain reaction illustrated that Tchsp18.3 is expressed in all developmental stages, and is highly expressed at early pupal and late adult stages, while it is highly expressed in ovary and fat body at the adult period. Moreover, it was up-regulated 4532 ± 396-fold in response to enhanced heat stress but not to cold stress; meanwhile the lifespan of adults in ds-Tchsp18.3 group reduced by 15.8% from control group under starvation. Laval RNA interference (RNAi) of Tchsp18.3 caused 86.1% ± 4.5% arrested pupal eclosion and revealed that Tchsp18.3 played an important role in insect development. In addition, parental RNAi of Tchsp18.3 reduced the oviposition amount by 94.7%. These results suggest that Tchsp18.3 is not only essential for the resistance to heat and starvation stress, but also is critical for normal development and reproduction in T. castaneum.

Roles of programmed cell death protein 5 in inflammation and cancer (Review).

PDCD5 (programmed cell death 5) is an apoptosis related gene cloned in 1999 from a human leukemic cell line. PDCD5 protein containing 125 amino acid (aa) residues sharing significant homology to the corresponding proteins of species. Decreased expression of PDCD5 has been found in many human tumors, including breast, gastric cancer, astrocytic glioma, chronic myelogenous leukemia and hepatocellular carcinoma. In recent years, increased number of studies have shown the functions and mechanisms of PDCD5 protein in cancer cells, such as paraptosis, cell cycle and immunoregulation. In the present review, we provide a comprehensive review on the role of PDCD5 in cancer tissues and cells. This review summarizes the recent studies of the roles of PDCD5 in inflammation and cancer. We mainly focus on discoveries related to molecular mechanisms of PDCD5 protein. We also discuss some discrepancies between the current studies. Overall, the current available data will open new perspectives for a better understanding of PDCD5 in cancer.

PDCD2 and NCoR1 as putative tumor suppressors in gastric gastrointestinal stromal tumors.

PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. Previously, PDCD2 (programmed cell death protein 2) has been identified as a putative tumor suppressor in gastric cancer. As yet, however, no reports on PDCD2 expression and its physical interactor NCoR1 (nuclear receptor co-repressor), and their effects in GIST have been reported. METHODS: The expression of PDCD2 and NCoR1 was assessed in 43 primary gastric GIST and normal gastric tissue samples using Western blotting and quantitative real-time PCR. Next, associations between PDCD2 and NCoR1 expression and various clinicopathological features, including survival, were determined. To assess the effects of PDCD2 and NCoR1 expression in vitro, two GIST-derived cell lines (GIST-T1 and GIST882) were (co-)transfected with the expression vectors pEGFP-N1-PDCD2 and pcDNA3.1-NCoR1, after which the cells were subjected to CCK-8, PI staining and Annexin V-FITC/PI double staining assays, respectively. Finally, the mechanisms of action of PDCD2 and NCoR1 in GIST-derived cells were determined using immunoprecipitation and Western blotting assays. RESULTS: We found that the PDCD2 and NCoR1 protein levels were lower in gastric GIST tissues than in normal gastric tissues. The PDCD2 and NCoR1 expression levels were found to be significantly associated with the survival of the patients. Through exogenous expression analyses, we found that PDCD2 and NCoR1 can decrease proliferation, and increase apoptosis and G1 cell cycle arrest, in GIST-derived cells. Furthermore, we found that PDCD2 and NCoR1 can activate Smad2 and Smad3. CONCLUSIONS: Our data indicate that both PDCD2 and NCoR1 may act as tumor suppressors in GIST cells through the Smad signaling pathway.