Bacillus suppresses nitrogen efficiency of soybean-rhizobium symbiosis through regulation of nitrogen-related transcriptional and microbial patterns.

The regulation of legume-rhizobia symbiosis by microorganisms has obtained considerable interest in recent research, particularly in the common rhizobacteria Bacillus. However, few studies have provided detailed explanations regarding the regulatory mechanisms involved. Here, we investigated the effects of Bacillus (Bac.B) on Bradyrhizobium-soybean (Glycine max) symbiosis and elucidated the underlying ecological mechanisms. We found that two Bradyrhizobium strains (i.e. Bra.Q2 and Bra.D) isolated from nodules significantly promoted nitrogen (N) efficiency of soybean via facilitating nodule formation, thereby enhanced plant growth and yield. However, the intrusion of Bac.B caused a reverse shift in the synergistic efficiency of N2 fixation in the soybean-Bradyrhizobium symbiosis. Biofilm formation and naringenin may be importantin suppression of Bra.Q2 growth regulated by Bac.B. In addition, transcriptome and microbiome analyses revealed that Bra.Q2 and Bac.B might interact to regulateN transport and assimilation, thus influence the bacterial composition related to plant N nutrition in nodules. Also, the metabolisms of secondary metabolites and hormones associated with plant-microbe interaction and growth regulation were modulated by Bra.Q2 and Bac.B coinoculation. Collectively, we demonstrate that Bacillus negatively affects Bradyrhizobium-soybean symbiosis and modulate microbial interactions in the nodule. Our findings highlight a novel Bacillus-based regulation to improve N efficiency and sustainable agricultural development.

Effects of N fertilizer reduction combined with straw biochar application on the yield, Si, and N nutrition of double-cropping rice.

Nitrogen (N) and silicon (Si) are important nutritional elements for rice. However, excessive N fertili-zer application and the ignorance of Si fertilizer are common in practice. Straw biochar is rich in Si, which can be used as a potential Si fertilizer. In this study, we conducted a consecutive 3-year field experiment to explore the effects of N fertilizer reduction combined with straw biochar application on rice yield, Si and N nutrition. There were five treatments: conventional N application (180 kg·hm-2, N100), 20% N reduction (N80), 20% N reduction with 15 t·hm-2 biochar (N80+BC), 40% N reduction (N60), and 40% N reduction with 15 t·hm-2 biochar (N60+BC). The results showed that compared with N100, 20% N reduction did not affect the accumulation of Si and N in rice; 40% N reduction reduced foliar N absorption, but significantly increased foliar Si concentration by 14.0%-18.8%; while combined application of biochar significantly increased foliar Si accumulation, with an increase of Si concentration by 38.0%-63.3% and Si absorption by 32.3%-49.9%, but further reduced foliar N concentration. There was a significant negative correlation between Si and N concentration in mature rice leaves, but no correlation between Si and N absorption. Compared with N100, N reduction or combined application of biochar did not affect soil ammonium N and nitrate N, but increased soil pH. Nitrogen reduction combined application of biochar significantly increased soil organic matter by 28.8%-41.9% and available Si content by 21.1%-26.9%, with a significant positive correlation between them. Compared with N100, 40% N reduction reduced rice yield and grain setting rate, while 20% N reduction and combined application of biochar did not influence rice yield and yield components. In summary, appropriate N reduction and combined with straw biochar can not only reduce N fertilizer input, but also improve soil fertility and Si supply, which is a promising fertilization method in double-cropping rice fields.

Significant difference in the efficacies of silicon application regimes on cadmium species and environmental risks in rice rhizosphere.

Silicon (Si) is commonly applied as base-fertilizer or foliar-topdressing to palliate the uptake-translocation-accumulation of cadmium (Cd) in rice through Si-Cd antagonism. However, little is known about the fate of Cd in rice rhizosphere soil and its eco-environmental effects under different Si treatments. Here, systematic works had been carried out to elucidate the Cd species, soil properties, and environmental risks in rice rhizosphere driven by different Si soil-fertilization regimes including CK (without Si-addition), TSi (added before transplanting stage), JSi (added at jointing stage), and TJSi (split into two equal parts, added half before transplanting and another half at jointing stage). Results showed that TJSi outperformed the rest of fertilization regimes. The solid-phase-Cd concentrations treated with TSi, TJSi and JSi were increased by 4.18%, 5.73% and 3.41%, respectively, when compared to CK. The labile Cd (F1+F2) proportion of TJSi was reduced by 16.30%, 9.30% and 6.78%, respectively, when compared to CK, TSi, and JSi. Simultaneously, the liquid-phase-Cd concentration was appreciably suppressed by TJSi throughout the rice lifecycle, while TSi mainly abated Cd dissociation during the vegetative period, and JSi attenuated it during the grain-filling stage. The mobility factor of Cd treated with TJSi was the lowest, which was significantly lower than that of TSi (9.30%) and JSi (6.78%), respectively. Similarly, the oral exposure risk of TJSi was reduced by 4.43% and 32.53%; and the food-chain exposure risk of TJSi was decreased by 13.03% and 42.78%. Additionally, TJSi was the most effective in promoting enzyme activities and nutrient content in rhizosphere soil. Overall, TJSi is more positive and sustainable than TSi and JSi in reconstructing Cd-contaminated rhizosphere environments and abating the environmental risks of Cd. Agronomic practices in Cd-contaminated paddy soils can be informed by applying Si-fertilizer separately before transplanting and at jointing stage to achieve soil welfare and food security.

[Impacts of biochar and phosphorus application on soil phosphorus availability and soybean phosphorus uptake]. / ä¸åŒç£·æ°´å¹³é æ–½ç”Ÿç‰©ç‚­å¯¹åœŸå£¤ç£·æœ‰æ•ˆæ€§.

Biochar is beneficial to soil phosphorus (P) availability and crop growth, but the effects vary greatly across different soil types. We investigated the effects of rice straw biochar (4% of total mass) and P application (0, 30, and 90 kg P·hm-2) on soil P availability, phosphomonoesterase activity, and soybean P uptake by using lateritic red soil (pH 4.91) and cinnamon soil (pH 7.24) as test materials. The results showed that biochar application at different P levels significantly increased available P and total P in both soils. Biochar application with 30 kg P·hm-2 increased soil available P with maxima at 192.6% and 237.1% in lateritic red soil and cinnamon soil, respectively. Biochar application with 30 kg P·hm-2 in lateritic red soil significantly increased the activity of alkaline phosphomonoesterase by 78.9%, decreased the content of active organic P by 39.3%, and subsequently stimulated soybean P absorption and growth. Biochar amendment significantly reduced active organic P content in cinnamon soil, but did not affect soil phosphomonoesterase activity and plant growth. The content of active organic P was significantly negatively correlated with soil available P content. In summary, the effect of biochar on soil P availability varied across different soil types (lateritic red soil > cinnamon soil) and P levels (better at 30 kg P·hm-2). Our results could provide scientific basis for a promising application of biochar in reducing the amount of P fertilizer and increasing soybean P uptake, especially in lateritic red soil.

The Cd sequestration effects of rice roots affected by different Si management in Cd-contaminated paddy soil.

The application of exogenous silicon (Si) reportedly is one of the eco-friendly practices to mitigate cadmium (Cd) phytotoxicity and regulate the chemical behaviors of Cd in the soil-rice system. But the efficiency of Si on the Cd retention by rice root varies with the Si fertilizer management. The objective of this paper was to interpret the differences in Cd immobilization by rice roots and relevant mechanisms under different ways of Si application (T-Si, supplied at transplanting stage; TJ-Si, split at transplanting and jointing stage with the ratio of 50 % to 50 %; J-Si, supplied at jointing stage and CK, none of Si application) in Cd-contaminated paddy soils. The results showed that the Cd-retention capacity of rice root was increased by 0.60 % ~ 3.06 % under different Si management when compared to CK. The concentrations of monosilicic acid in soils and in apoplast and symplast of roots were increased significantly by Si application, while Cd concentrations in apoplast and symplast of root were decreased by 28.50 % (T-Si), 40.64 % (TJ-Si) and 30.26 % (J-Si), respectively. The distribution of Cd in rice cell wall was increased significantly by TJ-Si. The Cd concentrations of inert fractions (F3, F4 and F6) in root of TJ-Si were raised obviously. Si application downregulated the expression of OsIRT2 and OsNramp5 while upregulated OsHMA3, and the expression of OsHMA3 treated by TJ-Si was obviously higher than CK and J-Si. The distributions of the passive Cd in roots bound with thiol compounds (NPT, GSH and PCs) and polysaccharide components (pectin, hemicelluloses 1 and hemicellulose 2) were raised much more by TJ-Si than by T-Si and J-Si. On the whole, compared with T-Si and J-Si, TJ-Si could more easily replenish soil available Si and enhance Cd sequestration in roots as the result of the decrease of Cd transport factor in roots. This study unravels some mechanisms about different Si management on increasing Cd retention and decreasing Cd migration in rice roots, and TJ-Si is worthy of being recommended.

Silicon enhances the submergence tolerance of rice by regulating quiescence strategy and alleviating oxidative damage.

The safety of rice production under submergence is one of the research hotspots worldwide. Although the effects of silicon (Si) on enhancing plant stress tolerance have been widely investigated, the underlying mechanisms mediated by Si under submergence remains poorly understood. In this study, wild type (WT) and Si-defective mutant (lsi1) rice were chosen to investigate the mechanisms of Si-mediated rice resistance to submergence. Our results showed that Si addition effectively mitigated oxidative damages under submergence by reducing the content of hydrogen peroxide (H2O2) and superoxide (O2.-) in WT rice plants. Moreover, Si treatment increased rice yield by 21.5% for WT rice under submergence. The application of Si significantly inhibited the elongation and internode length in WT rice under submergence, through the synergistic regulation of endogenous hormones ethylene (ET), gibberellic acid (GA) and jasmonic acid (JA). Further investigation showed that the ethylene-responsive factor (ERF) SUB1A gene was expressed under submergence in WT and lsi1 rice, but Si addition did not influence the expression of SUB1A. Interestingly, exogenous Si down-regulated the relative expression levels of Si transporter genes Lsi1 and Lsi2 in WT rice roots by 51.7% and 48.0%, respectively. However, the physiological characteristics and genes expression of lsi1 rice were not affected by Si application regardless of submergence. The present study indicated that Si enhances the submergence tolerance and reduce the adverse effects of yield loss through the removal of reactive oxygen species and the adjustment of quiescence strategy.

Abatement of Cd in rice grain and toxic risks to human health by the split application of silicon at transplanting and jointing period.

Silicon (Si) has the potential to ameliorate the toxic effects of cadmium (Cd) on rice growth and mitigate Cd-uptake by rice under Cd-contaminated soil. However, it is not completely clear whether there are differences in the impacts of different Si management on the chemical behavior of Cd in soil-rice system under Cd-contaminated paddy field. Here, pot trials were conducted to explore the effects of three modes of Si application (T-applying Si at transplanting stage, J-applying Si at jointing stage, TJ-applying Si at transplanting stage and jointing stage with a ratio of 50% to 50%) on the accumulation of Cd in rice grain and the toxic risk of Cd on human health in rice consumption under Cd-polluted soil (4.21 mg·kg-1), and that without Si application was used as control (CK). Results showed that rice growth and Cd-retention in root were enhanced by Si application, and the retention of Cd in TJ root was the highest, reaching 82.36%∼84.06% of total Cd absorbed by rice plant. TJ also elevated soil pH and CEC value significantly during the whole growth period, diminished Cd availability and converted exchangeable-Cd into residual-Cd in soil. Moreover, Si application reduced Cd concentration in iron plaque, while TJ had the lowest concentration of DCB-Cd and the highest molar ratios of Fe/Cd and Mn/Cd. The bioaccessibility of Cd from grains and cooked rice were decreased by Si application. Compared with T and J, the hazard quotient of digestion from cooked white rice of TJ in gastric phase was reduced by 19.61% and 21.94%, respectively. In brief, TJ had more efficiency on reducing the Cd availability in soil during the rice growing period, promoting the retention of Cd in root, decreasing Cd uptake by rice plant and distribution to grains, as well as the bioaccessibility of Cd from cooked rice. These results also provide a novel strategy of Si application to decrease the risk of Cd migration in the soil-rice-humans system and simultaneously promote rice yields.

Biochar application under low phosphorus input promotes soil organic phosphorus mineralization by shifting bacterial phoD gene community composition.

Biochar has the potential to enhance microbial-mediated phosphorus (P) cycling in soils, but the underlying mechanisms remain largely unknown. We hypothesized that biochar amendment could enhance the production of acid and alkaline phosphomonoesterase, phosphodiesterase and P mineralization, which may vary depending on the P input. To test this hypothesis, we assessed the impacts of rice straw biochar application (0 and 4%) under different P-input rates (0, 30 and 90 kg P ha-1) on the relationships among P fractions, phosphatase activities and alkaline phosphomonoesterase-encoding bacterial (phoD gene) communities in an acidic soil. Biochar application under low P input (< 30 kg P ha-1) significantly increased the activities of phosphodiesterase and alkaline phosphomonoesterase but not that of acid phosphomonoesterase and depleted organic P. The results from the structural equation model revealed a dominant role of alkaline phosphomonoesterase in P mineralization. The increase in alkaline phosphomonoesterase activity was not related to an increase in phoD gene abundance but was due to a shift in community composition, which was primarily driven by the soil C:P ratio. Microbial network analysis demonstrated a more complex phoD gene community with more functionally interrelated groups as a result of biochar application under low P input than under high P input. Moreover, the specific enrichment of Micromonosporaceae under C-rich and P-poor conditions may play a critical role in alkaline phosphomonoesterase production and potential P mineralization. In conclusion, we demonstrated that biochar application under low P input supports a more organized phoD gene community and preferentially enriches taxa in terms of their capacity for P mineralization, which in turn may enhance P bioavailability and plant P acquisition.

Regulating effects of silicon on Cd-accumulation and stress-resistant responding in rice seedling.

Silicon (Si) application could significantly alleviate the toxic effects of cadmium (Cd) on the growth and development of rice. Here, we examined the regulatory effects of Si on Cd accumulation and stress response in rice seedlings through a hydroponic root separation test. The results showed that the biomass of rice seedlings decreased significantly under Cd stress, while the addition of Si could alleviate such negative effect. The uptake, transfer, and accumulation of Cd in rice seedling were significantly affected by Si addition under Cd stress. Si application under the unilateral Cd stress (Si-Cd+Si, Si-Cd) increased Cd-retention coefficient of root by 83.3%-83.6%, which restricted the transfer of Cd from root to aboveground. However, the treatment with Si added to the non-stressed side (Si-Cd) elevated the uptake and accumulation of Cd in rice seedling, with the accumulation in root being increased by 48.2% when compared to the treatment under the unilateral Cd stress without the addition of Si (CK-Cd). The treatment with Si added in two sides (Si-Cd+Si) decreased the uptake of Cd both in root and aboveground parts by 36.7% and 54.9%, respectively. The addition of Si under bilateral Cd stress (Cd-Cd+Si) significantly reduced the Cd uptake of both the root and aboveground parts by 57.8% and 46.5%, respectively, compared to the treatment of bilateral Cd stress (Cd-Cd). Higher Si concentration in rice seedling was found under the Cd stress. More Si was accumulated in rice seedling to resist the Cd stress when Si was added. The addition of Si affected the absorption of other metal elements in rice seedlings, including calcium (Ca), magnesium (Mg) and manganese (Mn). The concentrations of Ca and Mg in root and aboveground parts were significantly increased by Si addition under bilateral Cd-stress (Cd-Cd+Si), but Mn concentration was changed with the stress degree of Cd. The activities of superoxide dismutase (SOD) and peroxidase (POD) in root were affected by Si under Cd stress, especially for the Si-Cd treatment. The activity of POD in the root of the Cd-stress side and that of SOD in non-stress side were significantly increased, which benefit to scavenging the free radicals induced by Cd stress. In conclusion, Si could regulate the growth of rice seedlings, the uptake of elements such as Cd and Si, and the antioxidant reaction of the root system under the Cd stress. High Si concentration in plant is conducive to enhancing Cd tolerance.

[Effects of nitrogen fertilizer reduction and biochar application on paddy soil nutrient and nitrogen uptake of rice]. / å‡æ°®é æ–½ç¨»ç§†ç”Ÿç‰©ç‚­å¯¹ç¨»ç”°åœŸå£¤å »åˆ†åŠæ¤æ ªæ°®ç´ å¸æ”¶çš„å½±å“.

We explored the impacts of nitrogen (N) reduction and biochar application on soil fertility and nutrient uptake of rice in early and late seasons of 2018 with a field experiment. There were six treatments, including control (no N application, CK), conventional N application (N100), 20% N reduction (N80), 20% N reduction plus biochar application (N80+BC), 40% N reduction (N60), 40% N reduction plus biochar application (N60+BC). Our results showed that 20% and 40% N reduction and/or with biochar application did not affect soil pH, organic matter, total N, total phosphorous (P), total potassium (K), ammonium N, available P and K in comparison with N100 treatment. N80+BC and N60+BC substantially increased soil cation exchange capacity (CEC) at tillering stage and electrical conductivity (EC) at heading stage in late season, respectively. Compared with the treatment with single N reduction, N80+BC significantly increased soil available K in early and late seasons and soil pH and total N in late season, while N60+BC increased soil total K at mature stage in early season. Soil nitrate content was decreased along with the growth stages for all treatments in early season. Compared with tillering stage, soil nitrate N content in conventional N application at heading stage and mature stage was decreased by 50.0% and 71.6%, respectively. Soil nitrate content in biochar treatment only was decreased by 6.3%-45.5%. N application along with biochar application had no significant effects on plant N uptake and utilization in early season. However, N reduction with biochar application significantly increased plant N uptake and N utilization rate by 34.8%-52.4% in late season, compared to conventional N application and single N reduction. Our findings suggest that adequate N reduction along with biochar application could maintain soil health and improve plant N uptake and utilization efficiency.

Cryobacterium ruanii sp. nov. and Cryobacterium breve sp. nov., isolated from glaciers.

Strains Sr36T and TMT4-23T were isolated from No. 1 glacier in Xinjiang Uygur Autonomous Region and Toumingmengke glacier in Gansu Province, PR China, respectively. They were Gram-stain-positive and rod-shaped micro-organisms. The optimum growth temperature of the two strains was 10-14 °C. Phylogenetic analysis showed that the two strains were related to members of the genus Cryobacterium. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain Sr36T and its close relatives Cryobacterium luteum Hh15T, Cryobacterium aureum Hh31T, Cryobacterium levicorallinum Hh34T and Cryobacterium flavum Hh8T were 81.16-87.24 and 28.0-32.5 %, respectively. The ANI and dDDH values between strain TMT4-23T and its close relative Cryobacterium psychrotolerans 0549T were 81.16 and 22.3 %. The polar lipids of strain Sr36T were diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid and three unidentified lipids. The polar lipids of strain TMT4-23T were diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid, one unidentified phospholipid and six unidentified lipids. The major fatty acids of strain Sr36T were anteiso-C15 : 0, iso-C16 : 0, anteiso-C17 : 0 and anteiso-C15 : 1. The major fatty acids of strain TMT4-23T were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0, anteiso-C15 : 1 and iso-C15 : 1. Both strains contained 2,4-diaminobutyric acid and their predominant menaquinone was MK-10. On the basis of the phenotypic, phylogenetic and genotypic data, two novel species Cryobacterium ruanii sp. nov. (type strain = Sr36T=CGMCC 1.9275T=NBRC 113797T) and Cryobacterium breve sp. nov. (type strain =TMT4-23T=CGMCC 1.9556T=NBRC 113800T) are proposed.

Apigenin exhibits anti-inflammatory effects in LPS-stimulated BV2 microglia through activating GSK3ß/Nrf2 signaling pathway.

Objective: Apigenin is a natural flavonoid compound extracted from Matricaria chamomilla. We evaluated the anti-inflammatory effects of apigenin in this study using the Lipopolysaccharide (LPS)-stimulated BV2 microglia.Methods: BV2 cells were treated with apigenin for 1 h and then treated with LPS. The inflammatory cytokine productions were tested by qRT-PCR and ELISA. The expression of GSK3ß, Nrf2, and NF-κB signaling pathways were measured by western blot analysis.Results: Apigenin significantly attenuated LPS-induced TNF-α, IL-1ß, and IL-6 production. Apigenin suppressed LPS-induced NF-κB activation. Furthermore, GSK3ß, Nrf2, and HO-1 were concentration-dependently increased by apigenin. The suppression of apigenin on LPS-induced inflammatory response and NF-κB activation were prevented when Nrf2 was knocked out or by GSK3ß inhibitor.Conclusions: Collectively, apigenin suppressed LPS-induced microglia activation via activating GSK3ß/Nrf2 signaling pathway.

Amentoflavone induces cell cycle arrest, apoptosis, and autophagy in BV-2 cells.

Previous studies have shown that amentoflavone (AF) elicits anti-inflammatory and neuroprotective effects. To further investigate the effects of AF on the microglia cell line BV-2, proteomic analysis was performed to screen potential key regulators. The top 5 canonical pathways associated with AF treatment were EIF2 signaling, regulation of eIF4 and p70s6k signaling, mTOR signaling, protein ubiquitination pathway and phagosome maturation. The top up-regulated genes were DOCK2, SEC23A, ME1, UGGT1 and STOM, while the most down-regulated molecules were IGF2R, ATP5O, DDX47, WBP11 and IKBIP. AF significantly decreased BV-2 cell proliferation. It induced cell cycle arrest at G2/M, increased CDK2, p27Kip1 and p53/p-p53, and decreased CDK1/CDC2 and cyclin B1. Cell apoptosis was induced, with increased levels of BAX, c-caspase-3 and c-caspase-9, and decreased levels of BCL-XL. Increased level of autophagosome induced by AF was observed, and increased Beclin-1 and decreased phosphorylation of PI3K and Erk1 were found as well. In conclusion, AF induces cell cycle arrest at G2/M, promotes apoptosis and autophagy in BV-2 cells, which may account for the anti-inflammatory effect of AF in epilepsy.

Biochar Suppresses Bacterial Wilt of Tomato by Improving Soil Chemical Properties and Shifting Soil Microbial Community.

The role of biochar amendments in enhancing plant disease resistance has been well documented, but its mechanism is not yet fully understood. In the present study, 2% biochar made from wheat straw was added to the soil of tomato infected by Ralstonia solanacearum to explore the interrelation among biochar, tomato bacterial wilt resistance, soil chemical properties, and soil microbial community and to decipher the disease suppression mechanisms from a soil microbial perspective. Biochar application significantly reduced the disease severity of bacterial wilt, increased soil total organic carbon, total nitrogen, C:N ratio, organic matter, available P, available K, pH, and electrical conductivity. Biochar treatment also increased soil acid phosphatase activity under the non-R.-solanacearum-inoculated condition. High-throughput sequencing of 16S rRNA revealed substantial differences in rhizosphere bacterial community structures between biochar-amended and nonamended treatments. Biochar did not influence soil microbial richness and diversity but significantly increased the relative abundance of Bacteroidetes and Proteobacteria in soil at the phylum level under R. solanacearum inoculation. Furthermore, biochar amendment harbored a higher abundance of Chitinophaga, Flavitalea, Adhaeribacter, Pontibacter, Pedobacter, and Ohtaekwangia at the genus level of Bacteroides and Pseudomonas at the genus level of Proteobacteria under R. solanacearum inoculation. Our findings suggest that a biochar-shifted soil bacterial community structure can favorably contribute to the resistance of tomato plants against bacterial wilt.

Cryobacterium melibiosiphilum sp. nov., a psychrophilic bacterium isolated from glacier ice.

A psychrophilic, Gram-stain-positive, rod-shaped bacterium, designated Hh39T, was isolated from Xinjiang No. 1 glacier in PR China. Strain Hh39T was catalase-positive, oxidase-negative and could grow at 0-18 °C, pH 6.0-11.0 and in the presence of 0-2.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Hh39T belonged to the genus Cryobacterium. The highest level of 16S rRNA gene sequence similarities were found to the type strains of Cryobacterium levicorallinum (99.01 %), Cryobacterium luteum (98.90 %), Cryobacterium aureum (98.90 %) and Cryobacterium roopkundense (98.75 %). However, the low average nucleotide identity (80.65-81.89 %) and digital DNA-DNA hybridization values (22.1-23.8 %) between strain Hh39T and its four closest relatives indicated that it represents a novel species of the genus Cryobacterium. The predominant fatty acids were anteiso-C15:0, anteiso-C15:1, iso-C16:0 and anteiso-C17:0. The major menaquinone was MK-10. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified lipid and one unidentified glycolipid. On the basis of results of phenotypic, genotypic and phylogenetic analyses, a novel species, Cryobacterium melibiosiphilum sp. nov., is proposed, with Hh39T (=NBRC 107884T=CGMCC 1.11212T) as the type strain.

Heavy metal bioaccumulation and cation release by growing Bacillus cereus RC-1 under culture conditions.

In an effort to explore the detoxifying mechanisms of B. cereus RC-1 under heavy metal stress, the bioaccumulation by growing cells under varying range of pH, culture time and initial metal concentration were investigated from a perspective of cation release. The maximum removal efficiencies were 16.7%, 38.3%, 81.4% and 40.3% for Cu2+, Zn2+, Cd2+ and Pb2+, respectively, with initial concentrations of 10 mg/L at pH 7.0. In presence of Cu2+ or Zn2+, large quantities of cations were released into the medium in descending order of Na+>K+>Ca2+>Mg2+, while bioremoval of the two essential metals Cd2+ and Pb2+ was accompanied with cellular Na+ and Mg2+ uptake from the medium, respectively. The relative mean contributions of intracellular accumulation to the total removal were approximately 19.6% for Cu2+, 12.8% for Zn2+, 51.1% for Cd2+, and only 4.6% for Pb2+. Following exposure at high concentration, B. cereus RC-1 could keep intracellular Cd2+ concentrations constant, possibly by means of a Cd-efflux system whose activity coincided with uptake of Na+, and reduce intracellular Pb2+ concentration due to the effect of Mg2+ on limiting Pb2+ access to the cells. Cellular morphology, surface functional groups and intracellular trace elements were further investigated by SEM-EDX, TEM-EDX, FTIR and ICP-MS analysis. The phenomena that removal of Cd2+ and Pb2+ coincided with uptake of Na+ and Mg2+, respectively, inspires a novel research perspective towards the study of protective mechanism of bacterial cells against the toxicity of heavy metals.

Expression of matrix metalloproteinase-9, type IV collagen and vascular endothelial growth factor in adamantinous craniopharyngioma.

To explore the expression of matrix metalloproteinase 9 (MMP-9), type IV collagen (Col IV) and vascular endothelial growth factor (VEGF) in adamantinomatous craniopharyngioma (ACP) and analyze the correlation between the level of these markers and adamantimous craniopharyngiomas recurrence. Expressions of MMP-9, Col IV and VEGF were tested by immunohistochemistry (IHC) in 40 cases of ACP, including 24 cases of primary group and 16 cases of recurred group. The expression level of MMP-9 and VEGF in recurred group were significantly higher than primary group (93.7% vs. 41.7%, P < 0.05, 87.5% vs. 45.8%, P < 0.05, respectively). The expression of Col IV in the recurred group was significant different from the primary group (Z = -2.619, P < 0.05). MMP-9, Col IV and VEGF may be the potential specific bio-marker related to the recurrence of ACP.