ATP in soil: A new extractant and extraction procedure

An extraction mixture comprised of 0.67 m H₃PO₄, 2 m urea, 20% DMSO, 1.8 mg of adenosine, 20 mM EDTA, and 1% Zwittergent 3,10 and a procedure to extract ATP from soil have been developed. The reagents and method were tested on six different Oklahoma soils and yielded a recovery of 99% of the ATP from added Escherichia coli cells. The extraction mixture was designed to minimize interference from soil-derived materials. The phosphoric acid provides acid to extract ATP and to inactivate proteins, and phosphate to saturate phosphate-binding sites. It also complexes or precipitates metal ions. The EDTA chelates metal ions, prevents inhibition of luciferase, and aids lysis of bacterial cells. The adenosine serves to saturate ATP binding-sites. Urea denatures proteins and prevents hydrogen bonding of the released ATP. DMSO, the Polytron treatment, and Zwittergent 3,10 remove cells from surfaces and lyse them. An internal standard of E. coli cells is used to determine efficiency of extraction and assay. When compared with the 12 best methods suggested by previous studies, the newly-formulated extractant and procedure yielded the greatest amount of ATP from soil.     

Extraction of bacterial lipopolysaccharides from soil samples and their determination using the Limulus amebocyte lysate reaction

Lipopolysaccharides were extracted from soil using an aqueous phenol procedure and determined by using the Limulus amebocyte lysate coagulation reaction. When heat-killed Escherichia coli cells were added to soil at a concentration of organisms expected to occur in subsurface material, there was a 10% recovery of the added cellular lipopolysaccharides (LPS); because of the sensitivity of the Limulus amebocyte lysate (LAL) reaction this recovery is sufficient for the method to be a rapid (4 h) estimate of the Gram-negative bacteria present in soil samples. By using a kinetic assay LPS could be measured over a concentration range of five orders of magnitude, which is important with environmental samples.     

Long-term efficacy of a deltamethrin-impregnated collar for the control of the Australian paralysis tick, Ixodes holocyclus, on dogs

Objective To determine the duration of efficacy of a 4% deltamethrin‐impregnated collar for dogs (Scalibor® ProtectorBand, MSD Animal Health) against adult female paralysis ticks (Ixodes holocyclus). Procedures A controlled pen study was conducted. Dogs were artificially infested at 14‐day intervals with unfed adult female ticks for up to 140 days following application of the collar to the dogs. Efficacy was assessed by manually counting ticks on dogs at 24, 48 and 72 h after each infestation. Results Efficacy at the 72‐h count was 96% after the day 14 tick infestation. The 72‐h efficacy remained above 94% from the day 14 to the day 98 infestations, when efficacy was still 99.5%. Efficacy at 72 h was above 90% after the day 112 infestation and was still 93% at 72 h after the day 140 infestation. Conclusions The deltamethrin‐impregnated collar gave greater than 90% control of paralysis ticks for at least 14 weeks.     

Proposal of a 2-tier histologic grading system for canine cutaneous mast cell tumors to more accurately predict biological behavior

Currently, prognostic and therapeutic determinations for canine cutaneous mast cell tumors (MCTs) are primarily based on histologic grade. However, the use of different grading systems by veterinary pathologists and institutional modifications make the prognostic value of histologic grading highly questionable. To evaluate the consistency of microscopic grading among veterinary pathologists and the prognostic significance of the Patnaik grading system, 95 cutaneous MCTs from 95 dogs were graded in a blinded study by 28 veterinary pathologists from 16 institutions. Concordance among veterinary pathologists was 75% for the diagnosis of grade 3 MCTs and less than 64% for the diagnosis of grade 1 and 2 MCTs. To improve concordance among pathologists and to provide better prognostic significance, a 2-tier histologic grading system was devised. The diagnosis of high-grade MCTs is based on the presence of any one of the following criteria: at least 7 mitotic figures in 10 high-power fields (hpf); at least 3 multinucleated (3 or more nuclei) cells in 10 hpf; at least 3 bizarre nuclei in 10 hpf; karyomegaly (ie, nuclear diameters of at least 10% of neoplastic cells vary by at least two-fold). Fields with the highest mitotic activity or with the highest degree of anisokaryosis were selected to assess the different parameters. According to the novel grading system, high-grade MCTs were significantly associated with shorter time to metastasis or new tumor development, and with shorter survival time. The median survival time was less than 4 months for high-grade MCTs but more than 2 years for low-grade MCTs.     

Indwelling rumino-reticulum bolus radio beacon

A miniature battery-powered radio beacon attached to a stainless steel bolus housing an osmotic pump is described. When the bolus, of sufficient size and density to be retained in the reticulum, is administered to ruminants the radio signal can be received, using a standard AM broadcast receiver up to a range of 1.5 m. The unit allows making a simple and inexpensive verification that the drug delivery system is still within the rumino-reticulum during long-term drug delivery studies and making an external estimation of the internal anatomic location of the device.     

Use of counter immunoelectrophoresis in detection of antibodies to tickborne fever

A micromethod using the counter immunoelectrophoresis technique for the detection of antibodies to Cytoecetes phagocytophila, the causative agent of tickborne fever (TBF) is described. Antibodies were first detected nine to 11 days after experimental infection of lambs with TBF and persisted for six to 10 weeks after infection. The test was also applied to approximately 440 field samples of ovine sera collected from tick infested farms in Scotland and the north of England, 16 per cent of which proved positive and showed a marked seasonal variation.     

Relationships between counts of nasopharyngeal bacteria, temperature, humidity and lung lesions in veal calves

Nasopharyngeal swabs were taken from four groups of veal calves at intervals throughout their growth and the aerobic bacteria cultivated from the swabs counted. The calves were kept under three different husbandry systems; naturally ventilated straw-yards, fan-ventilated crates and crates with a controlled climate. The numbers of bacteria isolated varied in a complex manner; however, in one group of calves a significant proportion (P less than 0.01) of the variation in weekly bacterial counts was associated with the changes in vapour pressure and temperature which took place between two and four days previously. In calves kept at a constant temperature of 16 degrees C, the bacterial populations in the nasopharynx were at a minimum between 65 and 75 per cent relative humidity and tended to rise at humidities outside this range. There was a temporal relationship between nasopharyngeal bacteria and lung lesions. In three groups the numbers of bacteria in calves at nine weeks old were positively correlated (P less than 0.05) with lung damage observable at 16 to 18 weeks old.     

Estimating soil salinity by disjunctive kriging

Abstract. Disjunctive kriging provides minimum variance estimates of properties from non-linear combinations of spatially correlated sample data. In addition it can be used to estimate the conditional probability that some critical threshold is exceeded or that there is a deficit at unsampled points. The technique has been applied to estimate and map the salinity of the soil in the Bet Shean Valley of Israel from measurements of electrical conductivity. In November 1985 the estimated electrical conductivity of the soil exceeded 4 mS per centimetre throughout most of the region, and in only a small area was the probability of salinity less than 0.2. By March 1986 the electrical conductivity had declined everywhere to less than 4 mS per centimetre, and the conditional probability of exceeding this value nowhere exceeded 0.25. Despite the fluctuation in salinity farmers seem to have it under control. The results suggest that winter wheat is likely to germinate poorly in the saltier parts of the region and that lucerne (alfalfa, Medicago sativa) is unlikely to yield its maximum over most of it. Cotton, a summer crop sown in spring, should not suffer.     

Horizontal resistance in tomato against the Meloidogyne-Fusarium complex: an artefact of parasitic epistasis

In a disease complex, epistatic and hypostatic parasites interact and modify the host response in such a way that the final disease reaction mimics quantitative reaction types. Data from an experiment using Meloidogyne incognita (Kofoid and White) Chitwood and Fusarium oxysporum f. lycopersici Snyd. and Hans. on tomato support the hypothesis that horizontal resistance against root pathogens may be an artefact of disease complexes. The implications, for crop protection, of the occurrence of disease complexes are discussed.