Enhancement of carotenoid production and its regulation in edible mushroom Cordyceps militaris by abiotic stresses.

Cordyceps militaris carotenoids are widely used as food additives, animal feed supplements, and so on. However, the biosynthetic pathway of carotenoids in C. militaris is still obscure. In this paper, changes of mycelial morphology and carotenoid accumulation of C. militaris were investigated under oxidative (KMnO4) and osmotic stress (NaCl). Subsequently, qRT-PCR was employed to detect the expression levels of genes related to carotenogenesis to explore the mechanism of adaptation to abiotic stress. When the concentrations of KMnO4 and NaCl were respectively 0.4 g/L and 2 g/L, carotenoid accumulation reached a maximum of 6616.82 ±â€¯666.43 µg/g and 6416.77 ±â€¯537.02 µg/g. Under the oxidative stress condition of KMnO4, the expressions of psy and hsp70 increased significantly compared with control. Besides, the genes fus3 and hog1 were significantly enriched in the MAPK signal pathway. Compared with the control group, there was no significant difference in expression of psy in the NaCl group. Moreover, the accumulation of triacylglycerols may contribute significantly to the increase in carotenoid accumulation. The increased accumulation of antioxidant carotenoids induced under environmental stress is to resist oxidative conditions. Fus3 and Hog1 signaling in the MAPK pathway was activated and subsequently take effects on the resistance of oxidative condition by regulating related metabolic processes. C. militaris resist the stress of high oxygen by producing a large amount of glycerol and carotenoids when this fungus is cultured in a saline environment for a long time.

[Spatial distribution of Se in soils from different land use types and its influencing factors within the Yanghe Watershed, China].

Based on different land use types, altitudes, soil and vegetation types etc, 171 representative topsoils (0-10 cm) were collected within the Yanghe watershed, China for determining the total concentrations, spatial distribution and influencing factors of selenium (Se). The results showed that the total selenium concentrations in soils within the watershed ranged from 0.02 to 3.24 mg x kg(-1) dry weight (dw). The geometric mean of Se in soils within the watershed was 0.30 mg x kg(-1), which was higher than those in Beijing plain (0.20 mg x kg(-1)), Hebei plain (0.19 mg x kg(-1)) and China (0.29 mg x kg(-1)). Soils which lacked Se (0.13-0.18 mg x kg(-1)) were mainly distributed in Huaian, Xuanhua, and Huailai counties. Se concentrations in most areas within the watershed were sufficient (0.18-0.45 mg x kg(-1)). In addition, Wanquan, Xinghe, Tianzhen and Yanggao counties also had some selenium-rich areas. Concentrations of Se were different under different land use types. They were of the following order: forest land > industrial and mining land > grassland > agricultural land. Agricultural land had the lowest concentrations of Se, with a mean concentration of 0.28 mg x kg(-1). We also found that parent materials and soil types had no significant effects on soil Se concentrations within the Yanghe Watershed. The results indicated that Se concentrations were positively and significantly correlated with clay contents and altitudes, but negatively and significantly with pH values. Furthermore, TOC, Fe and Al concentrations were also important factors influencing the Se concentrations in soils within the Yanghe Watershed.

Regulation effect of polysaccharides from Pleurotus tuber-regium (Fr.) on the immune activity of mice macrophages.

Pleurotus tuber-regium (Fr.) is widely consumed as a nutritious food due to its multiple health effects, especially immune function. This study was aimed at investigating its immune activity using the mice peritoneal macrophage model. Two polysaccharides, water and alkaline extraction of polysaccharides (W-PTR and A-PTR), from P. tuber-regium were used to test their immune functions and compare their possible activity differences. Results showed that both W-PTR and A-PTR showed a significant enhancement effect on the macrophage phagocytosis, and could activate the related enzymes, such as ATPases, lysozyme, and LDH, which are responsible for providing the maturation and proliferation process of macrophages with sufficient energy. In addition, levels of intracellular cytokines (IL-1, TNF-α, NO) were significantly increased after being treated with polysaccharides. A-PTR displayed a better performance than W-PTR in almost all tests. It is concluded that both polysaccharides could enhance the immune system by activating the macrophages and related enzymes, and induce the release of cytokines, indicating that polysaccharides are responsible for the immune function of Pleurotus tuber-regium (Fr.).

[Distribution and enrichment of nutrients in superficial sediment in Tianjin typical waters].

Concentrations of organic matter (OM), total nitrogen (TN), total phosphorus (TP) and bioavailable phosphorus (BAP) were determined in superficial sediment (0-25 cm) collected from 4 selected typical waters (Yuqiao reservoir, Haihe River, Haihe estuary and Bohai Bay) in Tianjin, China. Pollution index (P(i)) and enrichment factors (EF) were taken to analyze nutrients enrichment and dynamic characteristic. The results show that 4 typical waters are polluted by anthropogenic source and much higher than the permissible limits which most benthos can bearing, the concentrations of OM, TN, TP and BAP are decreasing progressively by the order: Haihe River > Haihe estuary> Bohai Bay Tianjin Sea Area. EF for OM, TN, TP and BAP reaches 1.6-6.5, 0.9-2.7, 0.9-2.6 and 4.4-9.2, respectively. The concentrations of BAP in different waters are inconsistent with those of TP, the ratio of BAP to TP in Yuqiao reservoir is the biggest, 16.3%, which shows endogenous source release is serious and eutrophication is the key problems of water pollution. The concentrations of OM and BAP increase in large scale between 1988 and 2005, TP basically keeps unchanging and TN slightly increases. Around Haihe River sediment dredging, nutrient concentrations (OM, TN and TP) of superficial sediments in Haihe River reduce to 57.7%, 82.8% and 85.2% of original concentration, respectively. And sediment dredging plays a positive role in nutrients removal.