Bibliothek

Notizen: Abstract Eradication is the elimination of every single individual of a species from an area to which recolonization is unlikely to occur. Cost-benefit analyses of eradication programs involve biases that tend to underestimate the costs and overestimate the benefits. In this review, we (a) highlight limitations of current cost-benefit analyses, (b) assess eradication strategies from biological and sociological perspectives by discussing particular cases of successful and failed eradication efforts, and (c) briefly contrast eradication and ongoing area-wide control as pest management strategies. Two successful eradication programs involve the screwworm and cattle ticks. Gypsy moth and medfly eradication programs have not been successful, and subsequent captures of insects recur in eradication areas. In situations where heterogeneity of land use patterns make it difficult to prevent reinvasion of the pest, education and area-wide suppression are probably more realistic goals than eradication.

Notizen: One hundred and eighty-eight subjects with psoriasis of the scalp voluntarily participated in this multicenter, randomized, double-blind, active, and placebo-controlled study to evaluate the safety and efficacy of clobetasol propionate foam 0.05% (CP foam) relative to clobetasol propionate solution 0.05% (CP solution, Temovate® scalp application). Adult male and female subjects with moderate to severe disease were assigned to one of four treatment groups in a 2 : 1 : 2 : 1 ratio (CP foam : placebo foam : CP solution : placebo solution). Moderate to severe disease was defined as involvement of at least 10% of the scalp and a minimum score of 2 (0, none; 1, mild; 2, moderate; 3, severe; 4, very severe) for each of the primary signs of psoriasis (erythema, scaling, plaque thickness).Subjects applied study medication to the entire scalp twice daily for 14 consecutive days and were required to use DHS shampoo. No other therapy to the scalp was allowed. Pruritus, scaling, erythema, and plaque thickness were evaluated on days 0, 7, and 15, and after 2 weeks off treatment on day 28. In addition, both the investigator and subject evaluated the global response to treatment at days 15 and 28 using a seven-point grading scale (completely clear, almost clear, marked improvement, moderate improvement, slight improvement, no change, or worse). The number of subjects who were ‘‘completely clear’' or ‘‘almost clear’' (〉 90% clearing) were lumped together to determine treatment success. Safety was assessed via standard clinical laboratory panels (chemistry, hematology, urinalysis), physical examination, vital signs, and reported adverse events.In addition to the clinical study, the potency of CP foam relative to five other dosage forms of CP, as well as to betamethasone valerate lotion 0.1%, was determined in 24 healthy male and female subjects using a modification of the new vasoconstrictor procedure. 1Products were randomly applied to 3.14 cm 2sites on the ventral forearms at a dose of 10 μL, covered with a nonocclusive guard, then removed after 3 h with dry, cotton swabs. Skin color was measured at − 1, 1, 4, 8, 12, 24, and 30 h using a chromameter (Minolta, Ramsey, NJ). Vasoconstrictor potency was assessed from the area-under-the-skin-blanching curve (AUC) using the a* scale output of the chromameter.The percutaneous absorption of CP from both the foam and solution formulations was determined using the cadaver skin assay. 2Each product was applied to multiple sections of skin at a dose of 6–8 mg/cm 2, and the solution bathing the dermis was sampled at intervals and analyzed for CP content by high performance liquid chromatography.Investigators: Edwin A. Bronsky, md, Intermountain Clinical Research, Salt Lake City, UT; Frank E. Dunlap, md, Argus Research, Inc., Tuscon, AZ; Holly B. Faust, md, Indiana University, Indianapolis, IN; David P. Fivenson, md, Henry Ford Hospital, Detroit, MI; Alan M. Heller, md, San Jose Clinical Research, San Jose, CA; Paul A. Lehman, MS, University of Arkansas for Medical Sciences, Little Rock, AR; Dale E. Martin, md, Skin Surgery and Skin Tumor Medical Group of San Diego, San Diego, CA; Bruce H. Miller, md, Dermatology Associates Research Center, Portland, OR; S. David Miller, md, New England Research Center, North Dartmouth, MA; Jennie J. Muglia, md, Rhode Island Hospital, Providence, RI; Toivo E. Rist, md, Dermatology Associates of Knoxville, Knoxville, TN; Ronald C. Savin, md, Savin Dermatology Center, New Haven, CT; Linda F. Stein, md, Henry Ford Hospital, Detroit, MI; Kenneth J. Washenik, md, ph d, NYU Medical Center, New York, NY

Notizen: SYNOPSIS. Naturally occurring populations of the monarch butterfly, Danaus plexippus (L.) and the Florida queen butterfly D. gilippus berenice Cramer were found infected with Ophryocystis elektroscirrha sp. n. This neogregarine pathogen infects the hypodermal tissue, remains in micronclear schizogony until after pupation of the host, and then rapidly completes morphogenesis in the tissue that becomes the scales of the adult butterfly. The adult thus carries the spores externally; no internal infection was detected. The pathogen is unique in the genus Ophryocystis because: other species have all been reported from the Malphigian tubules of Coleoptera; no pseudopodial attachments of schizonts to host tissue were seen; the merozoites were motile; the cystic membrane surrounding the zygote was tenuous, and the sporont developed with no apparent membrane other than the spore wall: and the spore wall appeared amber in transmitted light when morphogenesis was completed.

Notizen: Abstract The expression and distribution of fumarate reductase activity was examined in Shewanella putrefaciens MR-1. Fumarate reductase was expressed at very low levels in aerobically grown cell and was markedly induced by growth under anaerobic conditions. Cells were fractionated into soluble and purified membrane components by four different methods. For all four methods used, and in marked contrast to the membrane-bound fumarate reductases of other bacteria, ≧ 98% of the fumarate reductase activity was localized in the soluble fraction. In cells subjected to osmotic shock or treated with lysozyme and EDTA to form spheroplasts, the specific activity of fumarate reductase was highest in the periplasmic fraction, while the majority of total fumarate reductase activity was in the cytoplasmic fraction.

Notizen: Abstract Mutants of Shewanella putrefaciens MR-1 deficient in menaquinone and methylmenaquinone, but which have wild-type levels of ubiquinone, retain the ability to use trimethylamine N-oxide as an electron acceptor, but they lose the ability to use nitrate, iron(III), and fumarate as electron acceptors. These mutants also show a reduced rate of manganese(IV) reduction. One of these mutants could be restored to essentially wild-type phenotype by supplementing the medium with 1,4-dihydroxy-2-naphthoic acid. A requirement for naphthoquinones in iron(III) reduction and a preference for naphthoquinones in manganese(IV) reduction provide further support that the metal reducing systems in MR-1 are linked to anaerobic respiration.

Notizen: Abstract The expression and distribution of ferric reductase activity was examined in Shewanella putrefaciens MR-1. Formate-dependent ferric reductase was not detected in aerobically grown cells but was readily detectable in anaerobically grown cells. Ferric reductase activity was found exclusively in the membrane fractions, with 54–56% in the outer membrane. In contrast, the majority of formate dehydrogenase was in the soluble fraction with lesser amounts associated with the various membrane fractions. Outer membrane ferric reductase activity was markedly inhibited by p-chloromercuriphenylsulfonate, 2-heptyl-4-hydroxyquinolone-N-oxide, and antimycin A, but was unaffected by the presence of alternate electron acceptors (nitrate, nitrite, fumarate, and trimethylamine N-oxide). Both formate and NADH served as electron donors for ferric reductase; activity with l-lactate or NADPH was poor. The addition of FMN markedly stimulated formate- and NADH-dependent ferric reductase.

Notizen: Abstract We examine the oviposition behavior of the parasitic fly Cyzenis albicans(Fall.) to determine if long-distance or contact chemical cues given off by damaged oak and apple foliage influences the attack of their host the winter moth Operophtera brumata(L.). Wind-tunnel experiments indicate the presence of an attractive odor in oak leaves and the absence of an attractant in apple leaves. The application of oak foliage extracts to apple trees increased the number of parasitoid eggs laid and the level of parasitism of winter moths in the field. The impact of altered host-seeking behavior by the parastoid is discussed in the context of the population ecology of its host.

Notizen: Summary Nine populations of cinnabar moth, introduced to North America as biological control agents of tansy ragwort, were studied for 4 to 6 years. We tested the hypothesis that good quality of the food plant, measured as percent protein, would destabilize the moth populations. A positive correlation occurred between the percent nitrogen in the plants and the coefficient of variation of moth population density. Moths tended to be larger and produce more eggs in areas with food plants of better quality. Larval survival was also correlated with the quality of the food and the fluctuation of the population density. Food plants with high nitrogen levels increase larval survival and moth fecundity and allow the moth populations to periodically overexploit their food supply, thus accentuating population fluctuations. This finding is discussed in relation to other studies of cinnabar moth.

Notizen: Summary The interactions between cinnabar moth, Tyria jacobaeae L. and its food plant, tansy ragwort, Senecio jacobaea L. were studied for 4 to 6 years at 9 sites in North America to assess if the herbivore drove the dynamics of the plants or if the plants determined the dynamics of the insects. Cinnabar moth larval density is not closely related to changes in the size and spacing of tansy ragwort plants although high densities of larvae were associated with a high proportion of rosettes the next year. Fluctuating moth populations live in areas where rosettes are small, closely spaced and numerous compared to flowering stem plants. This situation is also associated with greater larval dispersal which may lead to over exploitation of the food supply. The coefficient of variation of both the size of rosettes and the distance between clumps of plants is associated with the coefficient of variation in moth density. This suggests that the plants may be driving the dynamics of the insect populations. The size of the moth egg batches is correlated to the size of the flowering stem plants in the previous year, indicating an adjustment between moth fecundity and food plant size. The conclusion is that environmental factors such as weather and soil type determine to a large degree the characteristics and variation in the plant populations and this in turn controls the dynamics of the insects. The relation of this situation to the biological control of weeds is discussed.

Notizen: Summary Since the successful control of prickly pear cactus by Cactoblastis cactorum in Australia, populations of plants and moths have persisted at low densities in open woodland sites. A contagious egg distribution causes overcrowding of larvae on some plants but insures low levels or no attack of other plants. This prevents extinction of plants and insects. Cactoblastis moths choose plants with characteristics which may increase the success of their larvae. Field observations and cage experiments indicate that large, green cactuses near previously attacked cactuses receive more eggs. Plants which are actively photosynthesizing are also more attractive as oviposition sites. These oviposition preferences contribute to the observed contagious egg distribution. While open woodland Opuntia and Cactoblastis populations fluctuate around an equilibrium, pasture populations may better be described by the “hide and seek” model, with the woodland populations serving as refuges. Average plant quality and variation in quality are suggested as important components in the dynamics of this system.