Effects of cadmium stress on physiological indexes and fruiting body nutritions of Agaricus brasiliensis.

In this study, 0, 0.5, 1, 1.5, 2, 4, 6 and 8 mg·kg-1 of cadmium were added to the cultivation materials. In order to study the effects of different concentrations of Cd stress on J1 and J77, the contents of antioxidant enzymes, proline and malondialdehyde, Cd content, agronomic traits and yield of fruiting bodies of Agaricus brasiliensis were determined, and the nutritional components such as polysaccharide, triterpene, protein, total sugar and total amino acid were determined. The results showed that the physiological indexes of strain J1 and J77 changed regularly under different concentrations of Cd stress. J1 was a high absorption and low tolerance variety, while J77 was a low absorption and high tolerance variety. Low concentration of Cd promoted the growth of strain J1, and higher concentration of Cd promoted the growth of strain J77. The contents of protein and total amino acids in the two strains changed greatly, followed by polysaccharides, which indicated that Cd stress had the greatest impact on the three nutrients, and other nutrients were not sensitive to Cd stress.

Comparative transcriptome analysis reveals candidate genes related to cadmium accumulation and tolerance in two almond mushroom (Agaricus brasiliensis) strains with contrasting cadmium tolerance.

Cadmium (Cd) is a toxic metal occurring in the environment naturally. Almond mushroom (Agaricus brasiliensis) is a well-known cultivated edible and medicinal mushroom. In the past few decades, Cd accumulation in A.brasiliensis has received increasing attention. However, the molecular mechanisms of Cd-accumulation in A. brasiliensis are still unclear. In this paper, a comparative transcriptome of two A.brasiliensis strains with contrasting Cd accumulation and tolerance was performed to identify Cd-responsive genes possibly responsible for low Cd-accumulation and high Cd-tolerance. Using low Cd-accumulating and Cd-tolerant (J77) and high Cd-accumulating and Cd-sensitive (J1) A.brasiliensis strains, we investigated 0, 2 and 5 mg L-1 Cd-effects on mycelium growth, Cd-accumulation and transcriptome revealed by RNA-Seq. A total of 57,884 unigenes were obtained. Far less Cd-responsive genes were identified in J77 mycelia than those in J1 mycelia (e.g., ABC transporters, ZIP Zn transporter, Glutathione S-transferase and Cation efflux (CE) family). The higher Cd-accumulation in J1 mycelia might be due to Cd-induced upregulation of ZIP Zn transporter. Cd impaired cell wall, cell cycle, DNA replication and repair, thus decreasing J1 mycelium growth. Cd-stimulated production of sulfur-containing compounds, polysaccharides, organic acids, trehalose, ATP and NADPH, and sequestration of Cd might be adaptive responses of J1 mycelia to the increased Cd-accumulation. DNA replication and repair had better stability under 2 mg L-1 Cd, but greater positive modifications under 5 mg L-1 Cd. Better stability of DNA replication and repair, better cell wall and cell cycle stability might account for the higher Cd-tolerance of J77 mycelia. Our findings provide a comprehensive set of DEGs influenced by Cd stress; and shed light on molecular mechanism of A.brasiliensis Cd accumulation and Cd tolerance.

Seasonal Change in Microbial Diversity and Its Relationship with Soil Chemical Properties in an Orchard.

This study aimed to determine the microbial diversity at different soil depths (0-5 and 5-20 cm) in a subtropical orchard during different seasons (i.e., spring, summer and autumn) to advance knowledge of the roles of microbes in orchard ecosystem balance. In tracking experiments conducted in an orchard (established in 1996), the phospholipid fatty acid (PLFA) biomarker method was employed to determine the soil microbial system. The total PLFA concentration did not vary significantly between soil depths but changed between seasons. It peaked in the summer at 258.97 ± 23.48 µg g soil-1 from 0-5 cm and at 270.99 ± 58.94 µg g soil-1 from 5-20 cm. A total of 33 microbial fatty acid biomarkers were observed and identified in the sampled soil. The quantities of PLFAs for 29 microbial groups varied significantly between seasons, except for 15:0 iso 3OH, 15:1 iso G, 16:0 2OH, and 17:0 iso 3OH. The bacterial PLFAs and fungal and actinomycetic PLFAs in the orchard soil collected in summer were significantly more abundant than those collected in the spring or autumn (P < 0.01). The number of soil microorganism species (richness) and the Simpson and Shannon-Wiener indexes were all highest in summer. The total PLFAs, bacterial PLFAs, fungal PLFAs, actinomycetic PLFAs, richness, and Simpson and Shannon-Wiener indexes were all significantly negatively correlated with soil pH, total organic carbon (TOC), total nitrogen (TN) and the cation exchange capacity (CEC) (P < 0.05).

Chryseobacterium aurantiacum sp. nov., isolated from a freshwater pond used for Murray cod (Maccullochella peelii peelii) culture.

A yellow-pigmented, Gram-staining-negative, aerobic, non-motile and rod-shaped bacterium, designated strain F30T, was isolated from fresh water of a diseased farmed Murray cod with a profound ulceration pond in Zhejiang province, PR China. Growth was observed at NaCl concentrations of 0.5-3.5 % (w/v) (optimum, 1.5-2.0 %), temperatures of 10-35 °C (optimum, 28 °C) and pH 5.0-9.0 (optimum, 6.5). Phylogenetic analysis based on 16S rRNA gene sequences indicated that F30T represented a member of the genus Chryseobacterium, showing the highest similarity to Chryseobacterium jejuense DSM 19299T (99.0 %) and Chryseobacterium nakagawai NCTC 13529T (99.0 %), and less than 98.7 % similarity to other species of the genus Chryseobacterium with validly published names. The average nucleotide identity and in silico DNA-DNA hybridization values between F30T and the reference strains were 78.4-90.5 % and 2.6-42.5 %, respectively. The results of chemotaxonomic analysis indicated that the fatty acids, as well as the polar lipid profiles of F30T were similar to those of species of the genus Chryseobacterium, and the sole respiratory quinone was MK-6. On the basis of its phylogenetic, chemotaxonomic and phenotypic data, strain F30T represents a novel species, for which the name Chryseobacteriumaurantiacum sp. nov. is proposed. The type strain is F30T (=KCTC 62135T=MCCC 1K03457T).

Silage preparation and fermentation quality of kudzu, sugarcane top and their mixture treated with lactic acid bacteria, molasses and cellulase.

We studied silage fermentation of kudzu (KZ), sugarcane top (ST) and their mixtures treated with additives to be able to effectively use available local feed resources. The silages were prepared using KZ, ST, KZ 90% + ST 10%, KZ 80% + ST 20%, KZ 70% + ST 30% and KZ 60% + ST 40%, based on fresh matter (FM). These silages were treated with 108  colony-forming units/g epiphytic lactic acid bacteria (LAB), 5% molasses and 0.02% cellulase of FM. The KZ contained higher crude protein (CP; 14.52%) content and lower levels of neutral detergent fiber (NDF; 62.15%) than those of ST (6.84% CP and 64.93% NDF) based on dry matter (DM). The KZ 60% + ST 40% silage fermented well with a higher (P < 0.05) lactic acid content and lower (P < 0.05) pH than those of the other mixed silages. Silages treated with molasses had lower (P < 0.05) ammonia-N, NDF, acid detergent fiber, and hemi-cellulose contents as well as pH, but higher (P < 0.05) DM, water-soluble carbohydrate, and lactic acid contents, than those of the control, LAB and cellulase treatments. The results confirmed that KZ 60% + ST 40% was the best mixing ratio to prepare silage, and molasses improved silage fermentation and fiber degradation.

Draft Genome Sequence of Streptococcus sp. X13SY08, Isolated from Murray Cod (Maccullochella peelii peelii).

Streptococcus sp. X13SY08, isolated from freshwater Murray cod fish, likely presents a novel species of Streptococcus. Here, we present an annotated draft genome sequence of this species, which will improve our understanding of its physiology and pathogenesis.

[Effects of vegetation restoration on soil carbon and nitrogen cycles: a review].

Vegetation rehabilitation is one of the main means in managing soil and water loss, being able to effectively promote the development of eroded soil, improve the soil fertility level, enhance the soil microbial activities, and in further, affect the soil carbon and nitrogen cycles. Therefore, vegetation rehabilitation plays definite roles in the accumulation of soil organic carbon and nitrogen pools and the mitigation of greenhouse gases emission from soil. This paper summarized the effects of vegetation rehabilitation on the soil carbon and nitrogen cycles and the synergetic effects between soil quality and vegetation rehabilitation, and put forward the further research directions, which could provide the reference for the evaluation of the roles of vegetation rehabilitation in response to global climate change, and the practical guidance for the improvement of soil fertility and the recovery and sustainable development of degraded ecosystems.

Water hyacinth (Eichhornia crassipes) waste as an adsorbent for phosphorus removal from swine wastewater.

Both live plants and dried straw of water hyacinth were applied to a sequential treatment of swine wastewater for nitrogen and phosphorus reduction. In the facultative tank, the straw behaved as a kind of adsorbent toward phosphorus. Its phosphorus removal rate varied considerably with contact time between the straw and the influent. In the laboratory, the straw displayed a rapid total phosphorus reduction on a KH(2)PO(4) solution. The adsorption efficiency was about 36% upon saturation. At the same time, the water hyacinth straw in the facultative tank enhanced NH(3)-N removal efficiency as well. However, no adsorption was evident. This study demonstrated an economically feasible means to apply water hyacinth phosphorus straw for the swine wastewater treatment. The sequential system employed significantly reduced the land use, as compared to the wastewater stabilization pond treatment, for pollution amelioration of swine waste.

Use of biogas fluid-soaked water hyacinth for cultivating Pleurotus geesteranus.

Experiments were carried out to test the viability of growing Pleurotus geesteranus on media containing varying amounts of crushed water hyacinth slices, which were soaked in pig farm biogas fluid and dried. The water hyacinth material was utilized to substitute sawdust in the media for mushroom cultivation. Mushroom fruiting bodies harvested were evaluated for yield, amino acid and heavy metal contents. Among the eight treatment groups, the greatest yield and highest amino acid content in the mushrooms were obtained when the proportions of water hyacinth and sawdust in the medium were equal. The concentrations of heavy metals, Hg, Pb and Cd, in most of the present mushroom samples did not exceed the maximum allowed levels according to the limits set forth by the food hygienic and safety regulations for edible mushrooms in China. The proposed waste utilization of water hyacinth could conceivably benefit the environment in various aspects including conservation of forest by reducing the demand on natural woods for mushroom production.

[Effect of exogenous zinc addition on cell protective enzyme activities in the fruit bodies of Lentinus giganteus].

OBJECTIVE: The effects of exogenous Zn addition on cell protective enzyme activities in the fruit bodies of Lentinus giganteus were studied. METHODS: ZnSO4 was used as exogenous Zn and added into culture medium. The final Zn concentrations in culture media were 0, 10, 20, 30, 40, 50 mg/kg respectively. The activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), malondialchehyche (MDA) content and soluble protein content in the fruit bodies were analyzed by spectrophotometry; catalase (CAT) was determined by potassium permanganate titration. RESULTS: The content of soluble protein and SOD, POD and CAT activities in the fruit bodies of L. giganteus were significantly increased (P < 0.01), but PPO activity (P < 0.01) and MDA content (P < 0.05) was significantly decreased in the treatment of 30 mg/kg Zn concentration. The content of soluble protein and SOD, POD and CAT activities showed a decreasing trend with the increase of Zn concentration, but MDA content was significantly increased (P < 0.01 and P < 0.05). CONCLUSION: High Zn concentration caused the increase of MDA contents and the decrease of SOD, POD and CAT activities in the fruit body of L. giganteus. It will destroy the protective enzyme system, cause the accumulation of free radicals and thus intensify membrane lipid peroxidation. Appropriate Zn concentration improved the protective enzyme activities, and lightened the harm of membrane from lipid peroxidation.

[Research advances in carbon balance in subtropical hilly red soil].

Carbon balance is becoming a hotspot in global change and geo-science studies. The subtropical hilly red soil area in China is an important production base of foodstuffs and tropical and subtropical economical crops and woods, and also, is very important in carbon balance research because of its special ecological and geographic characters. This paper discussed the significance of subtropical hilly red soil in carbon balance, and reviewed the related research advances and main results, including plant, litterfall, soil carbon storage, and soil respiration etc. The integrative research methods of carbon balance were summarized, and some issues and development directions in carbon balance research were discussed.

[Dynamic changes of ecological footprint and ecological capacity in Fujian Province].

The analysis on the dynamic changes of ecological footprint and ecological capacity in Fujian Province showed that in 1999-2003, the ecological footprint per capita in the Province increased from 1.428 hm2 to 1.658 hm2, while the ecological capacity per capita decreased from 0.683 hm2 to 0.607 hm2, with an increased ecological deficit year after year. The contradiction between the ecological footprint and ecological capacity pricked up gradually, and the ecological environment was at risk. There existed a severe imbalance in the supply and demand of ecological footprint per capita. The main body of the demands was grassland and fossil fuel, accouting for 55.74% - 63.43% of the total, while their supply only occupied 0.77% - 0.82% and next to nothing of the ecological capacity per capita, respectively. As a whole, the ecological footprint per ten thousand yuan GDP declined in the five years, indicating that the resources use efficiency in the Province was improved gradually. Based on the analysis of the present situation of the economic development and resources distribution in the Province, the strategies on reducing ecological deficit were put forward.

[Effects of selenium on Chamaecrista rotundifolia growth, nutrient absorption and nitrogen-fixing ability].

In this paper, a field experiment was conducted on a red soil of South China to study the effects of applying selenium fertilizer on the growth, forage quality and nitrogen-fixing ability of Chamaecrista rotundifolia. The results showed that applying 75, 150, 225 and 300 g Se x hm(-2) could increase the plant height, branch number, dry root weight and dry forage yield by 0.3% - 6.2%, 65.1% - 79.5%, 155% - 252% and 30.6% - 54.1%, respectively. The total nitrogen, total phosphorus and total potassium contents of plant were increased by 21.79% - 41.46%, 20.74% - 34.67% and 34.3% - 62.4%, respectively, and the raw protein, raw fat, raw fiber and amino acid contents were increased by 21.79% - 41.46%, 1.4% - 89.6%, 34.1% - 56.6% and 6.33% 63.24%, respectively. Among the 4 doses, 150 g Se x hm(-2) was the most effective and suitable application amount. The selenium content in plant after applying 300 g Se x hm(-2)(S4) was 0.695 mg x kg(-'), with an increase of 0.658 mg x kg(-1) compared to no selenium fertilization. There was a significantly positive correlation between plant selenium content and applied selenium (R2 = 0.9666**). The root nodule weight, number and nitrogenase activity in treatment 150 g Se x hm(-2)(S2) were respectively 131.7%, 114.3% and 1417.9% higher than those of no selenium fertilization. The correlation between applied selenium and nitrogenase activity was also significant (R2 = 0.9606*).

[Research advance in characteristics of molybdenum, boron and selenium in red soils of South China and effects of their reasonable application on forage grass growth].

Reasonable fertilization and fertility improvement of red soils are the important measures to develop the forage industry in hilly regions of South China. This paper summarized the existing form, chemical feature, availability and content of molybdenum, boron and selenium in red soils of South China. The lack of these three microelements in red soils was in common, and their reasonable application could significantly improve the growth of forage grass and its yield. The authors discussed the effects of molybdenum, boron and selenium application on the uptake and accumulation of available nutrients by forage grass and relevant physiological functions, described the molybdenum, boron and selenium deficiency symptoms of forage grass, their diagnostic methods and correcting measures, and put forward some suggestions for deepening the study.