ELISA of polyclonal antibody to fish MT and study on heavy metal tolerance in fish

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Antibiotic Resistance and Heavy Metals Tolerance in Gram-Negative Bacteria from Diseased American Bullfrog (Rana catesbeiana) Cultured in Malaysia

A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog （Rana catesbeiana） cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. （46 isolates） followed by Aeromonas spp. （33 isolates）, Flavobacterium spp. （31 isolates）, and Vibrio spp. （30 isolates）. Majority of the bacterial isolates were found sensitive to furazolidone （85.0%）, chloramphenicol （85.0%）, oxolinic acid （90.0%）, florfenicol （95.0%）, and flumequine （97.5%）. On the other hand, most of the bacterial isolates were resistant to oleandomycin （77.5%） and lincomycin （87.5%）. Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance （MAR） index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals.

Cadmium and copper uptake and accumulation by Sesbania rostrata seedling, a N-fixing annual plant: implications for the mechanism of heavy metal tolerance

Sesbania rostrata,an annual tropical legume,has been found to be tolerant to heavy metals,with an unknown mechanism.It is a promising candidate species for revegetation at mine tailings.In this study,sequential extractions with five buffers and strong acids were used to extract various chemical forms of cadmium and copper in S.rostrata,with or without Cd or Cu treatments,so that the mechanisms of tolerance and detoxification could be inferred.Both metals had low transition rates from roots to the aboveground of S.rostrata.The transition ratio of Cd(4.00%)was higher than that of Cu(1.46%).The proportion of NaCl extracted Cd(mostly in proteinbinding forms)increased drastically in Cd treated plants from being undetectable in untreated plants.This suggests that Cd induced biochemical processes producing proteinlike phytochelatins that served as a major mechanism for the high Cd tolerance of S.rostrata.The case for Cu was quite different,indicating that the mechanism for metal tolerance in S.rostrata is metal-specific.The proportion of water-insoluble Cu(e.g.oxalate and phosphate)in roots increased significantly with Cu treatment,which partially explains the tolerance of S.rostrata to Cu.However,how S.rostrata copes with the high biotic activity of inorganic salts of Cu,which increased in all parts of the plant under Cu stress,is a question for future studies.Sesbania rostrata is among the very few N-fixing plants tolerant to heavy metals.This study provides evidence for the detoxification mechanism of metals in Sesbania rostrata.

Isolation and Physiological Characterization of Synechococcus cedrorum 1191 Strain Tolerant to Heavy Metals and Pesticides

The toxicity of heavy metals (Hg2 + , Zn2 + ) and pesticides has been investigated by comparing the physiological properties in wild and tolerant strains of Synechococcus cedrorum 1191. The differential pattern of growth, absorption spectra of pigments and nutrient uptake was observed in tolerant strain.

Subcellular Distribution and Chemical Forms of Cadmium in the Medicine Food Homology Plant Platycodon grandiflorum(Jacq.)A.DC.

Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd levels to be regulated or reduced,it is necessary to first elucidate the mechanism of Cd uptake and accumulation in the plant,in addition to its detoxification mechanisms.This present study used inductively couple plasma-mass-spectrometry to analyze the subcellular distribution and chemical forms of Cd in different tissues of P.grandiflorum.The experimental results showed that Cd was mainly accumulated in the roots[predominantly in the cell wall(50.96%-61.42%)],and it was found primarily in hypomobile and hypotoxic forms.The proportion of Cd in the soluble fraction increased after Cd exposure,and the proportion of insoluble phosphate Cd and oxalate Cd increased in roots and leaves,with a higher increase in oxalate Cd.Therefore,it is likely that root retention mechanisms,cell wall deposition,vacuole sequestration,and the formation of low mobility and low toxicity forms are tolerance strategies for Cd detoxification used by P.grandiflorum.The results of this study provide a theoretical grounding for the study of Cd accumulation and detoxification mechanisms in P.grandiflorum,and they can be used as a reference for developing Cd limits and standards for other medicine food homology plants.

Ectomycorrhizal fungi and dark septate endophyte inoculation improve growth and tolerance of Pinus tabulaeformis under cadmium stress

Forest trees can establish symbiotic associations with dark septate endophytes(DSEs)and ectomycorrhizal fungi(ECMF)simultaneously.However,the combined effects of these two fungi on the growth and cadmium(Cd)tolerance of host plants remain largely unexplored.To address this knowledge gap,a pot experiment was conducted to examine the effects of the interaction between an ECMF strain(Suillus granulatus)and a DSE strain(Pseudopyrenochaeta sp.)on Pinus tabulaeformis under Cd stress,by assessing plant growth and physiological parameters,nutrient uptake,and soil properties.Notably,the colonization rates of both fungal strains were found to increase in response to Cd stress,with the extent of this increase being influenced by the specific fungal species and the Cd level in the soil.Compared to the non-inoculation treatment,single inoculation with fungal strain resulted in enhanced biomass,root development,and nutrient contents in P.tabulaeformis seedlings under Cd stress.Furthermore,a synergistic effect was observed when these seedlings were co-inoculated with S.granulatus and Pseudopyrenochaeta sp.,as indicated by significantly greater measurements in various indicators compared to both the single and non-inoculation treatments.Fungal inoculation effectively regulated the antioxidant defense responses and photosynthesis of P.tabulaeformis seedlings subjected to Cd stress,particularly in the co-inoculation treatment.In addition,fungal inoculation facilitated the Cd accumulation in P.tabulaeformis,suggesting a promising potential for the implementation of bioremediation strategies in the areas contaminated with heavy metals.The findings from this study indicate that the utilization of root symbiotic fungi obtained from stress environments could potentially enhance the growth performance and tolerance of P.tabulaeformis towards heavy metals,and co-inoculation of both fungal groups may result in even more pronounced synergistic effects on the overall fitness of the plant.

Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxi-cities

Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxicities were assessed by a seed-suspending seedbed(SSS) approach. The results showed that the SSS approach was suitable for testing the tolerance of a plant to the stress of toxic metals. The endpoints include seed germination success, straightened radicle and hypocotyl of the seedlings from the seeds. The measurements could be done easily and accurately. It was found that the elongation of radicle was the most sensitive indicator to the stress of heavy metals among the endpoints. When exposure to lower or medium concentrations of Pb, Zn, and Cd, the development of the lateral roots were favorable. Species of S. rostrata was more tolerant than S. cannabina to the heavy metals, especially to Zn and Cd. The ED 50 of Pb, Zn, Cu and Cd were 32.90, 5.32, 4.40 and 12.00 μg/ml for S. rostrata, respectively, and they were 30.11, 2.87, 4.05 and 4.94 μg/ml respectively for S. cannabina.