Comment on "A bacterium that can grow by using arsenic instead of phosphorus"

Wolfe-Simon et al. (Research Articles, 3 June 2011, p. 1163; published online 2 December 2010) reported that bacterium GFAJ-1 can substitute arsenic for phosphorus in its macromolecules, including DNA and proteins. If such arseno-DNA exists, then much of the past century of work with arsenate and phosphate chemistry, as well as much of what we think we know about metabolism, will need rewriting.     

Small interannual variability of global atmospheric hydroxyl

The oxidizing capacity of the global atmosphere is largely determined by hydroxyl (OH) radicals and is diagnosed by analyzing methyl chloroform (CH(3)CCl(3)) measurements. Previously, large year-to-year changes in global mean OH concentrations have been inferred from such measurements, suggesting that the atmospheric oxidizing capacity is sensitive to perturbations by widespread air pollution and natural influences. We show how the interannual variability in OH has been more precisely estimated from CH(3)CCl(3) measurements since 1998, when atmospheric gradients of CH(3)CCl(3) had diminished as a result of the Montreal Protocol. We infer a small interannual OH variability as a result, indicating that global OH is generally well buffered against perturbations. This small variability is consistent with measurements of methane and other trace gases oxidized primarily by OH, as well as global photochemical model calculations.     

Metabolism and fate of [(14)C]ethametsulfuron-methyl in rutabaga (Brassica napobrassica Mill)

The metabolism and fate of ethametsulfuron-methyl ?methyl 2-[[[[[4-ethoxy-6-(methylamino)-1,3, 5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]benzoate? in rutabaga were investigated. After 72 h, absorption and translocation of [(14)C]ethametsulfuron-methyl in rutabaga did not change for the duration of the study (50 days). Less than 4% of recovered radioactivity was present in the rutabaga root. Ethametsulfuron-methyl was metabolized through a proposed unstable alpha-hydroxy ethoxy intermediate that dissipated 3 days after treatment to two major metabolites, O-desethylethametsulfuron-methyl and N-desmethyl-O-desethylethametsulfuron-methyl, as determined by liquid chromatography-mass spectrometry. It was estimated that at a spray dose of 30 g of active ingredient ha(-)(1) and a harvest weight of 0.5 kg, the edible portion of the rutabaga root would contain no ethametsulfuron-methyl and approximately 1.3 ppb total of both identified metabolites. Residue analysis and toxicological assessment show that ethametsulfuron-methyl and its metabolites should pose little or no risk to consumers of rutabagas.     

Analysis of methoxyfenozide residues in fruits, vegetables, and mint by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Methoxyfenozide [3-methoxy-2-methylbenzoic acid 2-(3,5-dimethylbenzoyl)-2-(1,1-dimethylethyl) hydrazide; RH-2485], in the formulation of INTREPID, was applied to various crops. Analysis of methoxyfenozide was accomplished by utilizing liquid-liquid extraction and partitioning, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Method validations for fruits, vegetables, and mint are reported. Methoxyfenozide mean recoveries ranged from 72 to 129% over three levels of fortification. The overall average of mean recoveries is 97 +/- 10%. The limit of quantitation for fruits, artichoke, cucumber, squash, and refined sugar was 0.010 ppm, with a detection limit of 0.005 ppm. For all other crops, the limit of quantitation was 0.050 ppm, with a detection limit of 0.025 ppm. No residues were found greater than the limit of quantitation in control samples. Residues above the limit of quantitation were found in all matrices except refined sugar. Foliage (bean, beet, pea, and radish) had greater residue levels of methoxyfenozide residue than their corresponding roots or pods. Other crop matrices contained <1.0 ppm of methoxyfenozide except artichoke, which had a mean of 1.10 ppm.     

通过人造卫星研究中国小麦矮腥黑穗病的潜伏地点

中国现有的小麦普通腥黑穗病是由Tilletia canies (DC.)Tul.和T. foetida(Wall) Liro引起的,但是,由T. cantroversa引起的小麦矮腥黑穗在中国未曾有过报道(Zhiyong Zhang, 1980,私人通讯).由于中国考虑到进口小麦带有矮腥黑穗菌孢子而引起潜在的矮腥黑穗病的流行,所以,1973年以来,从美国沿太平洋各州运往中国的小麦被禁运.     

Haptoglobin and serum amyloid A in milk from dairy cows with chronic sub-clinical mastitis

New tools are needed to detect chronic sub-clinical mastitis, especially in automatic milking systems. Haptoglobin and serum amyloid A (SAA) are the two most sensitive bovine acute phase proteins, and their concentrations increase in milk from cows with clinical mastitis and in milk from cows with experimentally induced chronic sub-clinical Staphylococcus aureus mastitis. The aim of this study was to further evaluate the potential for haptoglobin and SAA in milk as indicators of chronic sub-clinical mastitis. Quarter milk samples were collected from 41 cows with a mean composite milk somatic cell count (CSCC) above 300,000 cells/mL during at least two months prior to sampling. Quarter milk samples were also taken from eleven cows with a mean CSCC below 80,000 cells/mL during at least two previous months. These samples were analysed for haptoglobin, SAA, adenosine triphosphate (ATP) activity and bacterial growth. The samples were grouped according to their ATP, haptoglobin and SAA status. ATP+ samples had ATP > 2 x 10(-10) mol/mL, Hp+ and SAA+ samples had detectable levels of haptoglobin (> or = 0.3 mg/L) and SAA (> or = 0.9 mg/L), respectively. In udder quarter samples from healthy cows, 42 out of 44 samples belonged to the ATP-Hp-SAA- group. Among cows with chronic sub-clinical mastitis, the ATP+Hp+SAA+ group contained 66 out of 164 samples while 44 samples belonged to the ATP+Hp-SAA- group. Detectable levels of haptoglobin and SAA were found in 92 and 80 samples, respectively. Growth of udder pathogens was detected in 28 samples and Staphylococcus aureus was the most common bacteria. In conclusion, haptoglobin and SAA concentrations below the detection limit were considered as good indicators of healthy udder quarters. A substantial variation in haptoglobin and SAA concentrations in milk was observed in udder quarters with chronic sub-clinical mastitis.     

Neospora abortions in dairy cattle: diagnosis, mode of transmission and control

AIM: To determine the contribution of Neospora caninum to abortions on a dairy farm in NSW (Australia), determine the mode of transmission and develop and trial a control option for infection. METHODS: Two whole herd bleeds were conducted 12 months apart and the association between serological status and abortion events were calculated for a number of bovine abortifacients. Family trees were constructed for N. caninum seropositive cattle in the herd. Some N. caninum seropositive cows were culled from the herd and no female offspring was retained from seropositive cows. RESULTS: At the first whole-herd bleed in December 2002 a seroprevalence of 10.2% for N. caninum infection was detected. Cows with N. caninum infection were 13 times more likely to abort than uninfected ones. Seventy-five percent of seropositive animals in the herd were related, suggesting a high degree of congenital infection/transmission. Only 15% of infections were likely to be postnatally acquired. Selective culling of seropositive cows and not breeding from them reduced the number of seropositive animals. Only one newly sero-converted cow was detected at the second whole-herd bleed 12 months later. CONCLUSIONS: Seroepidemiological approaches were able to establish a high degree of association between N. caninum infection and low-level abortion in the dairy herd. Vertical transmission of infection was the predominant mode of infection and hence control efforts aimed at selectively culling seropositive animals from the herd were highly successful in reducing the level of infection.