Reversible reduction of oxygen to peroxide facilitated by molecular recognition

Generation of soluble sources of peroxide dianion (O(2)(2-)) is a challenge in dioxygen chemistry. The oxidizing nature of this anion renders its stabilization in organic media difficult. This Report describes the chemically reversible reduction of oxygen (O(2)) to cryptand-encapsulated O(2)(2-). The dianion is stabilized by strong hydrogen bonds to N-H groups from the hexacarboxamide cryptand. Analogous stabilization of peroxide by hydrogen bonding has been invoked recently in crystalline saccharide and protein systems. The present peroxide adducts are stable at room temperature in dimethyl sulfoxide (DMSO) and N,N'-dimethylformamide (DMF). These adducts can be obtained in gram quantities from the cryptand-driven disproportionation reaction of potassium superoxide (KO(2)) at room temperature.     

Analysis of volatile compounds as spoilage indicators in fresh king salmon (Oncorhynchus tshawytscha) during storage using SPME-GC-MS

A method was developed for the analysis of salmon volatiles using solid-phase microextraction and gas chromatography-mass spectrometry. This method was used to monitor the volatiles of fresh king salmon (Oncorhynchus tshawytscha) stored in ambient air or in a 40:60 (v/v) mixture of CO2:N2 over time. The levels of several of the volatile compounds were found to change during storage, with some showing a clear difference between storage in air and storage in CO2:N2. Of these, several alcohols (cyclopentanol, Z-2-penten-1-ol, 1-penten-3-ol, and 1-octen-3-ol) and aldehydes (hexanal, octanal, E-2-pentenal, and E-2-hexenal) were identified as potential markers for salmon freshness. Several other volatiles (acetoin, ethyl benzene, propyl benzene, styrene, 3-methyl butanoic acid, and acetic acid) were identified as potential markers for salmon spoilage. A comparison of salmon harvested with and without the "rested harvesting" technique showed that E- and Z-isoeugenol levels were increased by the use of the isoeugenol based anesthetic. The use of the anesthetic did not affect the levels of any of the other compounds identified.     

Spread of HTLV-I between lymphocytes by virus-induced polarization of the cytoskeleton

Cell contact is required for efficient transmission of human T cell leukemia virus- type 1 (HTLV-I) between cells and between individuals, because naturally infected lymphocytes produce virtually no cell-free infectious HTLV-I particles. However, the mechanism of cell-to-cell spread of HTLV-I is not understood. We show here that cell contact rapidly induces polarization of the cytoskeleton of the infected cell to the cell-cell junction. HTLV-I core (Gag protein) complexes and the HTLV-I genome accumulate at the cell-cell junction and are then transferred to the uninfected cell. Other lymphotropic viruses, such as HIV-1, may similarly subvert normal T cell physiology to allow efficient propagation between cells.     

Organic matter accumulation and fertilizer-induced acidification interact to affect soil microbial and enzyme activity on a long-term sugarcane management experiment

The effects of crop residue management and fertilizer applications on the size and activity of the microbial community and the activity of exocellular enzymes involved in mineralization of C, N, P and S were examined on a long-term (60 years) field trial under sugarcane situated at Mount Edgecombe, South Africa. Treatments at the site included pre-harvest burning with harvest residues removed (B), burning with harvest residues (unburnt tops) left on the soil surface (B_t) and green cane harvesting with retention of a trash blanket (T). Plots were either fertilized annually with N, P and K or unfertilized. The size and activity of the microbial community and the activity of soil enzymes assayed increased with increasing inputs of crop residues (B < B_t < T) and this effect was evident to a depth of 30 cm. The metabolic quotient was decreased by inputs of both crop residues and fertilizers. Annual fertilizer additions did not affect basal respiration, increased fluorescein diacetate (FDA) hydrolysis rate and acid phosphatase, invertase and protease activities and decreased arginine ammonification rate and dehydrogenase, alkaline phosphatase, arylsulphatase and histidase activities. These effects were attributed to an interaction between the positive effect of fertilizer in increasing the size of the microbial biomass and the negative effect of fertilizer-N-induced soil acidification on microbial activity and on the activity of exocellular enzymes. Such results demonstrate the importance of using a range of measurements of microbial and enzyme activity when determining the effects of management on soil microbial and biochemical properties.     

Analysis of feline,canine and equine hemograms using the QBC VetAutoread

Blood samples form 120 consecutive clinical cases (40 cats, 40 dogs and 40 horses) were analyzed on the QBC VetAutoread analyzer and the results compared with those obtained by a Baker 9000 electronic resistance cell counter and a 100-cell manual differential leukocyte (WBC) count. Packed cell volume (PCV), hemoglobin (Hb) concentration, mean cell hemoglobin concentration (MCHC), and platelet, total WBC, granulocytes, and lymphocyte plus monocyte (L+M) counts were determined. Indistinct separation of red blood cell and granulocytes layers on the QBC VetAutoread was observed in samples from five cats (12.5%), two dogs (5%), and one horse. Significantly different (P=0.002) median values for the two methods were obtained for PCV, Hb concentration, MCHC and platelet count in cats; PCV, MCHC, WBC, count and granulocytes count in dogs; and PCV, Hb concentration, MCHC and WBC, granulocytes and platelet counts in horses. Results from the QBC VetAutoread should not be interpreted using reference ranges established using other equipment. Results were abnormal on a limited number of samples; however, when correlation coefficients were low, marked discrepancy existed between values within as well as outside of reference ranges. Spearman rank correlation coefficients were excellent (r=0.93) for PCV and Hb concentration in dogs, and Hb concentration and WBC count in horses. Correlation was good (r=0.80-0.92) for PCV and Hb concentration in cats, WBC count in dogs, and PCV, granulocytes count and platelet count in horses. For remaining parameters, correlation was fair to poor (r=0.79). Acceptable correlations (r>0.80) were achieved between the two test systems for all equine values except MCHC and L+M count, but only for PCV and HB concentration in feline and canine blood samples.     

Retrospective analysis of serum and nasal mucus from cattle in Northern Ireland for evidence of infection with influenza A virus

Eighty-four pairs of acute and convalescent serum samples collected in 1998 and 1999 from 17 outbreaks of respiratory disease, milk drop syndrome or diarrhoea in cattle were tested by haemagglutination inhibition against human influenza viruses A/Eng/333/80 (HIN1) and A/Eng/427/88 (H3N2). Antibodies to these viruses were present in the convalescent sera of 56.5 per cent and 58.8 per cent cattle tested, respectively, with 56 per cent of the animals seroconverting to one or both viruses. Titres were typically higher to A/Eng/427/88 (H3N2). Further testing of a subset of 21 of these serum pairs against the predominant H1N1 and H3N2 human and porcine strains circulating when the samples were collected revealed that the highest reactivity, in terms of both the magnitude of the recorded titres and the number of positive sera, was to human H3N2 strains. The titres to human H1N1 strains and to both porcine subtypes were low or absent. Attempts to isolate influenza A virus from nasal mucus or swab samples from 142 cattle from 46 cases of respiratory disease and/or milk drop syndrome by passage in embryonated specific pathogen-free eggs were unsuccessful.