Modification and characterization of fibers of three sandy willow shrub species

Periploca sepium, Salix psammophila and Tamarix spp. make up an important part of the local vegetation in the sandland of China. This paper described a novel method on modification of the three shrub fibers as oil sorbents. Natural and modified fibers were chemically studied by non-destructive methods, infrared spectroscopy （IR） and cross-polarization nuclear magnetic resonance （CP-MAS ~3C-NMR）. The results show that during the reaction with acetic anhydride under mild conditions, the use of N-bromoscciniamide （NBS） catalyst resulted in a high weight percent gain （WPG）. The acetylation ofP sepium fiber gave rise to the highest WPG （20.0%） compared with S. psammophila and Tamarix spp. fiber. IR and CP-MAS ^13C-NMR analysis elaborates the chemical features of natural and acetylated willow fiber in detail.

Response of ATP sulfurylase and serine acetyltransferase towards cadmium in hyperaccumulator Sedum alfredii Hance

We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance.

Characterization of ^(68)Zn uptake,translocation,and accumulation into developing grains and young leaves of high Zn-density rice genotype

Zinc(Zn) is an essential micronutrient for humans,but Zn deficiency has become serious as equally as iron(Fe) and vitamin A deficiencies nowadays.Selection and breeding of high Zn-density crops is a suitable,cost-effective,and sustainable way to improve human health.However,the mechanism of high Zn density in rice grain is not fully understood,especially how Zn transports from soil to grains.Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique.At seedling stage,IR68144 showed higher 68Zn uptake and transport rate to the shoot for the short-term,but no signifi-cant difference was observed in both genotypes for the long-term.Zn in xylem sap of IR68144 was consistently higher,and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient(2.0 μmol/L) or surplus(8.0 μmol/L) Zn supply level.IR64 and IR68144 showed similar patterns of 68Zn accumulation in new leaves at seedling stage and in de-veloping grains at ripening stage,whereas 68Zn in new leaves and grains of IR68144 was consistently higher.These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.

Treatment of turtle aquaculture effluent by an improved multi-soil-layer system

Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20%（MSL 1, MSL 2, MSL 3, and MSL 4, respectively）. The turtle aquaculture effluent had an average chemical oxygen demand（COD）, ammonia nitrogen（NH4^＋-N） and total nitrogen（TN） concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN（C/N） ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4^＋-N, and TN, and MSL 4 showed significantly improved NH4^＋-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4^＋-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis（DGGE） profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4^＋-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.

Phenotype and metabolism alterations in PCB-degrading Rhodococcus biphenylivorans TG9^(T) under acid stress

Environmental acidification impairs microorganism diversity and their functions on substance transformation.Rhodococcus is a ubiquitously distributed genus for contaminant detoxification in the environment,and it can also adapt a certain range of pH.This work interpreted the acid responses from both phenotype and metabolism in strain Rhodococcus biphenylivorans TG9^(T)(TG9)induced at pH 3.The phenotype alterations were described with the number of culturable and viable cells,intracellular ATP concentrations,cell shape and entocyte,degradation efficiency of polychlorinated biphenyl(PCB)31 and biphenyl.The number of culturable cells maintained rather stable within the first 10 days,even though the other phenotypes had noticeable alterations,indicating that TG9 possesses certain capacities to survive under acid stress.The metabolism responses were interpreted based on transcription analyses with four treatments including log phase(LP),acid-induced(PER),early recovery after removing acid(RE)and later recovery(REL).With the overview on the expression regulations among the 4 treatments,the RE sample presented more upregulated and less downregulated genes,suggesting that its metabolism was somehow more active after recovering from acid stress.In addition,the response mechanism was interpreted on 10 individual metabolism pathways mainly covering protein modification,antioxidation,antipermeability,H+consumption,neutralization and extrusion.Furthermore,the transcription variations were verified with RT-qPCR on 8 genes with 24-hr,48-hr and 72-hr acid treatment.Taken together,TG9 possesses comprehensive metabolism strategies defending against acid stress.Consequently,a model was built to provide an integrate insight to understand the acid resistance/tolerance metabolisms in microorganisms.