Failure of white-tailed deer, Odocoileus virginianus L., to sustain a population of cattle ticks, Boophilus annulatus (Say), through successive generations

Cattle ticks, Boophilus annulatus (Say), previously reared only on cattle, were placed on 3 white-tailed deer, Odocoileus virginianus L. Ticks were maintained through successive generations solely on the same deer as they aged (3, 6, and 9 mo of age) and received repeated challenges (0, 1, and 2 previous challenges). Cattle were infested simultaneously to assess tick viability and provide a comparison of tick numbers, female weight, egg mass weight, and egg hatch. The initial infestation (3,000 larvae/animal) produced a mean of 12.7 and 506.7 females from deer and cattle, respectively. Ticks recovered from deer weighed less, laid smaller egg masses, and had lower egg hatchability than cattle-reared ticks. A second infestation (3,000 larvae/animal) produced a 6.3-fold reduction in tick numbers on deer (means = 2.0 females/deer), whereas the number on cattle increased (means = 578.0 females/calf). Ticks reared on the deer were again smaller, laid fewer eggs, and had lower egg hatch, although differences were not significant. A third infestation of deer (1,900 larvae/deer) produced only 1 engorged female tick and no viable eggs, thus eliminating the population of deer-reared ticks within 3 generations. Results of the study suggest that a population of B. annulatus will not be sustained indefinitely through time solely on deer; thus, efforts to reduce deer populations severely as a means of eradicating ticks are unnecessary.     

Efficacy and stability of wettable powder amitraz in field and laboratory studies against Boophilus annulatus (Acari: Ixodidae) in south Texas

A study was done at the USDA-ARS, Cattle Fever Tick Research Laboratory, Mission, Tex., to determine the efficacy of a 50% wettable powder (WP) amitraz formulation applied as a whole-body spray in a standard dip vat, and in a laboratory bioassay against Boophilus annulatus (Say) on cattle. A study also was done at the King Ranch in Kleberg County, Tex., to determine the stability of 50% WP amitraz in a dip vat under South Texas conditions Cattle were infested with all parasitic life stages of B. annulatus and were sprayed or dipped with a concentration of 0.025% amitraz. As determined by calculations of the index of reproduction, the whole-body spray treatment provided 86% control of the ticks and the dip treatment provided 99.8% control. Laboratory bioassay results compared favorably with those obtained with the dip vat treatment. Amitraz WP settled very rapidly in the freshly charged ranch vat. However, as more cattle were dipped and the vat became polluted with dirt and excrement, settling occurred much more slowly. Overall, amitraz remained stable in the vat during the test period.     

Quantitative derivatization and high-performance liquid chromatographic analysis of cyanobacterial heterocyst-type glycolipids.

Procedures are described for the rapid and quantitative analysis of cyanobacterial heterocyst-type glycolipids (HGs) by normal-phase HPLC of their per-O-benzoylated derivatives. Total lipids are obtained from 1 ml of nitrogen-fixing cyanobacterial culture by triplicate extraction with chloroform/methanol, 1/1 (v/v), and the HGs are isolated from other complex lipids by preparative silica gel TLC. A C18 solid-phase extraction cartridge is used to ensure quantitative salt-free recovery of the HGs, and the purified glycolipids are then rendered uv-absorbing by a per-O-benzoylation derivatization reaction for which optimal conditions have been established. Derivatives are analyzed within 12 min on a 3-microns silica HPLC column using a linear gradient of 2-propanol in n-hexane and uv monitoring at 230 nm. The reaction product was also used to determine the relative proportions of the glucosyl and galactosyl epimers of individual members of this class of glycolipid.     

Dielectric properties of human blood and erythrocytes at radio frequencies (0.2–10 MHz); dependence on cell volume fraction and medium composition

The dielectric properties of human erythrocytes (red blood cells) suspended in whole blood and in isotonic media at various volume fractions (haematocrits) have been studied in the frequency range 0.2–10 MHz, in which the so-called-dispersion due to the Maxwell-Wagner effect is known to occur. The capacitance and conductance at 25 °C were measured by an instrument interfaced to a computer. The rectangular sample cavity (1 ml volume) contained four pure gold electrode pins, and the sample could be circulated by a roller pump. The frequency-dependence of the permittivity and conductivity were fitted by non-linear least squares regression. Corrections were applied for non-linearity in the dielectric increment at high haematocrit, and for electrode polarisation when diluting the blood in saline. Data were interpreted in terms of a simple equivalent resistor-capacitor circuit. From the measured haematological values the specific membrane capacitance (C_m) and the conductivities internal and external to the cells (_i and _o respectively) were estimated. The conductivities behaved in a predictable manner with a mean of 0.458 S · m^–1 (s.d. ± 0.044) for _i, whereas the value of C_m (and indeed the actual capacitance of the suspension) was dependent on the amount of plasma present. Hence, in stationary normal (anticoagulated) whole blood samples, C_m was as high as 2.98 F · cm^–2 (s.d. ± 0.40), in contrast to about 0.9 F · cm^–2 in blood diluted more than two-fold (to less than 20% hct) in isotonic media. The high value remained when the diluent was plasma. The C_m value returned to a high value when washed erythrocytes were reconstituted with plasma, provided that this was present at above a critical or threshold concentration of about 30 vol % in the medium, irrespective of the haematocrit in the range studied (15–44%). The C_m remained low in serum. When added to washed cells in saline, purified fibrinogen had no effect. However, high C_m values were obtained by fibrinogen supplementation to serum and diluted plasma. Applying moderate flow to whole blood approximately halved its high C_m value in an exponential manner with flow rate, whilst the C_m of washed cells (31–67% hct) slightly increased, and converged to the value for whole blood under flow. We interpret the highapparent C_m value in stationary samples to be a result of rapid cell aggregation in the presence of plasma, where rouleaux formation takes place before visible sedimentation sets in.     

Transformation of passionfruit (Passiflora edulis fv flavicarpa Degener.) using Agrobacterium tumefaciens

Leaf and stem explants of passionfruit (Passiflora eadulis fv flavicarpa) were co-cultivated with a disarmed strain of Agrobacterium tunefaciens harbouring the co-integrate vector pMON200. Four plants of passionfruit were regenerated from leaf explants on agar-solidified Murashige and Skoog (1962) based medium containing 4.43 M 6-benzyl-aminopurine and supplemented with 86 M kanamycin sulphate. The four plants were rooted by transfer to MS based medium with 14.7 M 3-indolebutyric acid and 2.68 M -naphthyleneacetic acid for 7 d, followed by MS based medium lacking growth regulators. Both media used for rooting contained 172 M kanamycin sulphate. Rooted plants were potted and grown to maturity. Three of the plants synthesised nopaline and expressed neomycin phosphotransferase activity; DNA dot blot and polymerase chain reaction analyses confirmed the presence of the neomycin phosphotransferase gene in three plants.Abbreviations BAP 6-benzylaminopurine - CTAB hexadecy-Itrimethylammonium bromide - EDTA ethylenediaminetetraacetic acid - IBA 3-indolebutyric acid - MS Murashige and Skoog (1962) - NAA -naphthyleneacetic acid - NPTII neomycin phosphotransferase II - nptII neomycin phosphotransferase II gene - PCR polymerase chain reaction - SDS sodium dodecyl sulphate - Tris tris(hydroxymethyl)aminomethane     

Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.     

Xylem colonization of the legume Sesbania rostrata by Azorhizobium caulinodans

A novel pathway of invasion of the legume Sesbania rostrata by Azorhizobium caulinodans is described that involves colonization of the root xylem, possibly following entry into the natural fissures created during emergence of lateral roots. Azorhizobia were detected microscopically, and their presence confirmed by the expression of a lacZ reporter gene. We have shown that rhizobial Nod factors are not required for either xylem colonization or for crack-entry of lateral roots. We discuss the extent to which this discovery of xylem colonization by azorhizobia is likely to improve our understanding of both symbiosis and of pathogenicity in plant–bacterial interactions.     

Intranuclear cytoplasmic inclusions in aspirates of follicular neoplasms of the thyroid. A report of two cases

Two cases are reviewed in which the presence of intranuclear cytoplasmic inclusions in fine needle aspiration biopsy specimens of the thyroid suggested a diagnosis of papillary carcinoma. Subsequent surgical specimens were consistent with diagnoses of microfollicular adenoma and follicular carcinoma. These cases suggest that the presence of intranuclear inclusions in epithelial thyroid cells is not limited to papillary and medullary carcinoma, as some authors have suggested.     

The heterogeneity and acceptor specificity of human serum galactosyltransferase

Human serum was fractionated by high resolution agarose isoelectricfocusing and the galactosyltransferase activity profile was determined using the ovalbumin, mucin, glucose and N-acetylglucosamine acceptor assays. The four acceptors gave very similar activity profiles. There were minor quantitative differences in some of the 12 or more peaks of activity detected and the only qualitative difference between them was a minor peak at pH 3.90 (2% of the total activity) which reacted only with the mucin acceptor. This suggests that most of the isoenzymes of human serum galactosyltransferase have broad and similar acceptor specificities and that the heterogeneity seen in serum cannot be accounted for by acceptor-specific forms of the enzyme.     

The effect of ethoxyzolamide, an analogue of insect juvenile hormone, nor-adrenaline and iodine on changes in the optical path difference in the excretory cells and oesophagus during exsheathment in Haemonchus contortus

Davey K. G., Sommerville R. I. and Rogers W. P. 1982. The effect of ethoxyzolamide, an analogue of insect juvenile hormone, nor-adrenaline and iodine on changes in the optical path difference in the excretory cells and oesophagus during exsheathment in Haemonchus contortus. International Journal for Parasitology12: 509–513. Ethoxyzolamide, an inhibitor of carbonic anhydrase, markedly inhibits exsheathment of Haemonchus when the larvae are subsequently exposed to an exsheathing stimulus of CO₂ at 38.5°C. Ethoxyzolamide at 2 × 10^?5M does not prevent the increase in optical path difference in the oesophageal region which normally accompanies exsheathment, but markedly inhibits the increase in optical path difference in the excretory cells. An analogue of juvenile hormone (JHA; the methyl ester of 3,7,11 trimethyl-7,11-dichloro-2-dodecenic acid) does not affect the optical path difference in either the oesophagus or the excretory cells of ensheathed worms. When worms are artificially desheathed by exposure to NaOCl, a procedure which mimics the effect of CO₂ upon the oesophagus, but which does not affect the excretory cells, subsequent exposure to JHA at room temperature increases the optical path difference in the excretory cells. This increase is enhanced by subsequent incubation of the worms at 38.5°C at 30–60 min and further enhanced when CO₂ is present during the incubation at 38.5°C. The stimulation of the excretory cells by JHA is inhibited by ethoxyzolamide at 2 × 10^?5M. Noradrenaline at 10^?3M has no effect on ensheathed larvae, but causes an increase in optical path difference in the excretory cells of larvae desheathed with NaOCl. This increase is inhibited by ethoxyzolamide. A brief exposure to I₂ blocks the response of the excretory cells of both CO₂ and JHA, but does not significantly reduce the effect of nor-adrenaline. On the basis of these and previous results, it is proposed that both CO₂ and JHA stimulate a hypothetical CO₂ receptor which leads to the release of nor-adrenaline. The noradrenaline in turn stimulates, either directly or indirectly, the excretory cells.