Symbiotic hemolymph bacteria reduce hexavalent chromium to protect the host from chromium toxicity in Procambarus clarkii.

Hexavalent chromium (Cr(VI)) is a cytotoxic heavy metal pollutant that adversely affects all life forms. Interestingly, the crustacean Procambarus clarkii exhibits a relatively high tolerance to heavy metals. The underlying mechanisms remain unclear.

Uptake of arsenic species by turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) treated with roxarsone and its metabolites in chicken manure.

Roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (As) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown As species. The accumulation, transport and distribution of As species in turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.

[Investigation of As, Cu and Zn species and concentrations in animal feeds].

Seventy chicken and seventy-six pig feeds were collected from the feed stores in Guangdong province, and the species and concentrations of As, Cu and Zn were determined. We also examined the stability of roxarsone (ROX), one of the most widely used organoarsenical additives, either in the additive or in the feed at room temperature. The results showed that, averagely, the chicken and pig feeds contained 3.

[Pesticide residual status in litchi orchard soils in Guangdong, China].

Litchi is a famous tropical and subtropical fruit originated in South China. Guangdong is one of the most important litchi production areas in China. Two hundred and eight soil samples were collected in litchi orchards after harvesting the fruit, in which nine often-used pesticides including metalaxyl, mancozeb, carbendazim, deltamethrin, cypermethrin, cyhalothrin, dipterex, dimethoate and dichlorvos were detected.

[Bioavailability of As, Cu and Zn in two soils as affected by application of chicken manure and pig manure].

Animal manures contain higher As, Cu and Zn since organoarsenicals, copper and zinc additives are widely used in modern intensive animal production. A pot experiment in water spinach was conducted to investigate As, Cu and Zn bioavailability in a paddy soil (PS) and a lateritic red soil (LRS) applied with 2% and 4% (mass fraction) chicken manure (CM) and pig manure (PM), respectively. Soils without any fertilizer were included as the checks (CK).

Arsenic uptake by two vegetables grown in two soils amended with As-bearing animal manures.

Organoarsenicals are widely used as growth promoters in animal feed, resulting in unabsorbed arsenic (As) left in animal manures. A pot experiment was conducted to investigate the growth and As uptake of amaranth (Amaranthus tricolor Linn, a crop with an axial root system) and water spinach (Ipomoea aquatica Forsk, a crop with a fibrous root system) grown in a paddy soil (PS) and a lateritic red soil (LRS) amended with 2% and 4% (w/w) As-bearing chicken manure and pig manure, respectively. Soils without any fertilizers were the controls.

[Effect of continuous application of chicken and pigeon manure from poultry farms on concentrations of soil nutrients and heavy metals].

Animal manures of intensive livestock and poultry farms are composed of complex materials. Effect of continuous application of chicken manure (CM) and pigeon manure (PM) for six crops on soil nutrients and heavy metals was investigated in a vegetable soil in Guangzhou, south China. Application rates (N 0 - 450 kg x ha(-1)) of CM and PM were calculated considering their N contents.

[Yield and heavy metal content of Brassica parachinensis influenced by successive application of chicken manure].

High heavy metal content in animal manures commonly occurs in the world since microelement additives are widely used in intensive animal production. Successive field trials in Brassica parachinensis (BP) were conducted to investigate the influence of successive application of chicken manure (at the rate of) on the yield and heavy metal content of BP. The application rate of chicken manure was calculated by its N content and ranged from N 0-450 kg x hm(-2).

Salinity of animal manure and potential risk of secondary soil salinization through successive manure application.

To enhance animal productivity and maximize economic returns, mineral salts are routinely added to animal feed worldwide. Salinity and ionic composition of animal manure from intensive poultry and livestock farms in Guangdong province were investigated. Field experiments were conducted for six successive crops of Brassica Parachinensis to evaluate the possibility of secondary soil salinization by successive application of chicken manure (CM) and pigeon manure (PM) to a garden soil.

[Comparison of denatured and non-denatured PAGE-silver-staining detection of PCR product of microsatellites].

The genomic DNAs from six chicken breeds in China were amplified using two microsatellite primers. The PCR products were detected by non-denatured and denatured PAGE gels respectively, and the gels were dyed by silver. There were distinct differences between the two kinds of gel.

[Analysis of genetic relationship of egg-type chickens using microsatellite markers].

Twenty microsatellite markers were used to analyse the genetic relationship among four package lines (A, B, C, D) of egg-type chickens introduced in 2001 an 2002. The genetic heterozygosity, polymorphism information content (PIC), effective allele number, and genetic distance among lines were calculated and dendrogram was constructed to evaluate the genetic variability within line and genetic relations among lines. In total, 65 alleles in 20 microsatellite markers were detected.