Protein polymorphism in a feral population of the pigeon Columba livia domestica

Sixteen enzymatic and non-enzymatic proteins of the pigeon Columba livia domestica were examined electrophoretically. These proteins were presumed to be under control by 22 loci. Of the 22 loci, 6 were defined as polymorphic and 15 as monomorphic. Another locus was variable, but the variation was not genetically interpretable. Average heterozygosity calculated over 21 loci was 0.075.     

Use of two formulations and two application techniques to deliver Bacillus thuringiensis var. israelensis for the control of Musca domestica (Diptera: Muscidae) larvae and adults in poultry houses

A field study was carried out for 6 wks to assess, from both an efficiency and economic perspective, the effect of individual and integrated success of feeding and topical applications of two formulations of Bacillus thuringiensis var. israelensis (Bti) in controlling house fly (Musca domestica L.) larvae and adults in poultry houses. There was no significant difference between the 1 g and 2 g L^?1 spray applications of Bti. In the absence of spray applications, no significant differences in larval mortalities were observed between the 250 mg and 500 mg kg^?1 feed applications. The percentage mortality of larvae accomplished as a result of using a combination of 250 mg kg^?1Bti feed and 2 g L^?1 spray applications was equivalent to that obtained as a result of combining 500 mg kg^?1Bti and 1g L^?1 spray applications. Treatment with Bti caused significant reductions in the emergence (up to 74%) of house fly adults compared to the control. The fact that the emergence of adult house flies was affected by Bti treatments implies that Bti has sublethal effects on house fly larvae. The cost–benefit analysis (expressed in terms of mortality of larvae growing) indicated that the most effective combination for house fly larvae and adult house fly emergence control was the 500 mg kg^?1 of feed and 2 g L^?1 spray application combination that resulted in 67% larval mortality and a 74% decrease in adult house fly emergence. This study presents commercial users with various alternatives for possible combinations of the two Bti formulations.     

Evidence for a sex pheromone metabolizing cytochrome P-450 mono-oxygenase in the housefly

Direct evidence is presented for the role of a cytochrome P-450 monooxygenase (called mixed-function oxidase, or polysubstrate mono-oxygenase, PSMO) in the metabolism of the sex pheromone (Z)-9-tricosene to its corresponding epoxide and ketone in the housefly. A secondary alcohol, most likely an intermediate in the conversion of the alkene to the ketone, was also tentatively identified. The results of in vivo and in vitro experiments showed that the PSMO inhibitors, piperonyl butoxide (PB) and carbon monoxide, markedly inhibited the formation of epoxide and ketone from (9,10-³H) (Z)-9-tricosene. An examination of the relative rates of (Z)-9-tricosene metabolism showed that males exhibited a higher rate of metabolism than females with the antennae of males showing the highest activity of any tissue/organ examined. The major product from all tissues/organs was the epoxide. Data from experiments with subcellular fractions showed that the microsomal fraction had the majority of enzyme activity, which was strongly inhibited by PB and CO and required NADPH and O₂ for activity. A carbon monoxide difference spectrum with reduced cytochrome showed maximal absorbance at 450 nm and allowed quantification of the cytochrome P-450 in the microsomal fraction of 0.410-nmol cytochrome P-450 mg^?1 protein. Interaction of (Z)-9-tricosene with the cytochrome P-450 resulted in a type I spectrum, indicating that the pheromone binds to a hydrophobic site adjacent to the heme moiety of the oxidized cytochrome P-450.     

Calcium ion transport across discs of the cortical flesh of apple fruit in relation to fruit development

Transport of Ca²⁺ through discs of apple fruit tissue was examined in tissue taken at different stages of fruit development. Transport rates decreased with fruit development when cation exchange was the predominant influence on transport (with 10⁻⁶ M ⁴⁵CaCl₂ as the source solution). This decrease was associated with a reduction in relative cell wall surface area, cation exchange capacity and cell wall yield that occurred during fruit growth. When diffusion was the major transport force, and when transport was influenced by solution infiltration of the tissue disc (10⁻² M ⁴⁵CaCl₂ in the source solution), transport rates increased during fruit growth. This increment was related to increases in air space of the tissue. Ca²⁺ transport through apple fruit tissue is influenced by the extent and nature of the cell wall, changing proportions of air space and Ca²⁺ concentration in the extracellular solution.     

Cyanide controls enzymes involved in lipid and sugar catabolism in dormant apple embryos during culture

The activities of alkaline lipase (EC 3.1.1.3, AlkL), isocitrate lyase (EC 4.1.3.1. ICL), pyruvate kinase (EC 2.7.1.40. PK) and glucose–6–phosphate dehydrogenase (EC 1.1.1.49, G6PDH) were determined in cultured, dormant embryos of apple (Malus domestica Borb. cv. Antonówka), pretreated with gaseous HCN. The C₆/C₁ , ratio was estimated in the same material. The activities of AlkL and ICL were not stimulated by HCN pretreatment until the period of maximum stimulation of germination. The activity of G6PDH was inhibited by cyanide only late during the culture of embryos. Therefore, the changes in these activities are considered to be the result and not the cause of enhanced germination. On the other hand, also PK, active very early during the culture of embryos, was modified as a result of the treatment. The cyanide-induced changes in activity of this enzyme in cotyledons (inhibition followed by stimulation) were similar to those in the whole embryo, whereas its changes in the embryonal axis (stimulation followed by inhibition) resembled CN-induced changes in PK in axes of apple seeds submitted to cold stratification (Bogatek and Lewak 1988). The estimation of C₆/C₁ ratios partly confirmed these observations. A role of HCN-induced modifications of PK activity in embryonal dormancy is proposed.     

Controlling plant growth via the gibberellin biosynthesis system – I. Growth parameter alterations in apple seedlings

'York Imperial' apple seedlings ( Malus domestica Borkh.) were continuously supplied via the roots with paclobutrazol [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol)], a triazole GA biosynthesis inhibitor, at 0.68 μ M in a nutrient solution. In comparison to controls, seedlings treated with paclobutrazol for 66 days showed a 91% reduction in shoot length, a 66% reduction in leaf area but only a 17% reduction in leaf number. This effect could be reversed by GA₃ applied to the foliage at 71.4 μ M 0, 19 or 35 days after paclobutrazol was initially supplied and leaf area values for paclobutrazol-treated seedlings given both treatments did not differ significantly from controls. Plots of growth data indicate linearity of shoot longitudinal growth of GA₃-treated seedlings. Leaf area increase was non-linear after GA₃ treatment up to approximately 30 days, when the rate dropped. On a per shoot basis, leaf weight closely followed leaf area but on a per unit area basis, paclobutrazol-treated leaves were heavier than controls; GA₃ applications temporarily reversed this trend.     

Qualitative and quantitative changes in hemolymph proteins during an ovarian cycle and after insemination in Thermobia domestica (packard) (thysanura,lepismatidae)

Qualitative and quantitative investigations on the hemolymph proteins in the adult firebrat Thermobia domestica were performed during an ovarian cycle in inseminated and noninseminated females. Variations of hemolymph protein concentration were determined by Lowry's method. In addition, the proteins were studied by gradient slab gel electrophoresis using nondenaturing conditions and microdensitometry. Besides five major protein fractions, which are present in both sexes, three female-specific protein bands (vitellogenins) are found in the hemolymph and in maturing oocytes. These vitellogenins have molecular masses of 430, 300 and 240 kiloDalton. In fact, associated with the main 300-kD band, there were two smaller bands (320 and 280 kD) indistinguishable by densitometric measurement. Quantitative changes of vitellogenins are linked to oocyte maturation. These proteins appeared in the hemolymph before ecdysis, at the same time as the first yolk granules in the basal oocytes. They increased after ecdysis during the intense vitellogenic phase and decreased during chorion formation. In noninseminated females, in which all maturing oocytes are resorbed before chorion formation, the level of the 300 kD vitellogenins remained lower than in inseminated females. The quantity of vitellogenins fell only after complete oosorption. Thus insemination caused changes in the relative quantities of the different vitellogenic proteins.     

Diffusible IAA and dominance phenomena in fruits of apple and tomato

The relationships between indole-3-acetic acid (IAA) diffusing out of the fruit and competition among fruits, and between fruits and shoot tips were investigated using apple ( Malus domestica Borkh. cv. Jonagold) and tomato ( Lycopersicon esculentum Mill.) plants. Dominant fruits always had more diffusible IAA than subordinated, inhibited fruits. Alterations in dominance – by fruit- or shoot tip removal – led to significant changes in diffusible IAA by the remaining fruits. This change could be detected one day after dominance modification.
It is suggested that diffusible IAA is involved in the correlative signal regulating dominance relationship between fruits, and between fruits and shoots in apple and tomato.