Salt activation and inhibition of membrane ATPase from roots of the halophyte Atriplex nummularia

Abstract Salt-stimulated ATPase activity in membrane preparations obtained from roots of Atriplex nummularia Lindl. at pH 5 was not suscep-tible to inhibition by KC1 or NaCl up to 450 mol m-3 but showed a broad peak of activity between 150 and 300 mol m^?3. At pH 8 stimulation occurred at 50 mol m^?3 but concentrations above 100 mol m^?3 depressed activity below the level of the MgATPase activity. By contrast, preparations from roots of Pisum sativum L. at pH 5 showed maximal stimulation at 25 to 50 mol m^?3 of NaCl or KC1; concentrations higher than 150 mol m^?3 depressed activity below that of MgATPase activity. At pH 8 maximal stimulation was observed at 5 to 10 mol m^?3 NaCl or KC1 while the threshold for inhibition was reduced to 15 mol m^?3. With increasing salt concentrations the pH profiles for NaCl stimulation of Atriplex ATPase activity (expressed as the difference between treatment and control) showed a progressive displacement of the apparent optimum towards lower pH. The shift was not apparent when stimulation was expressed as a percentage of MgATPase activity. This shift may be accounted for if NaCl stimulated the monovalent salt-activated ATPase activity but simultaneously inhibited MgATPase activity.     

Effect of mating frequency and brood cell infestation rate on the reproductive success of the honeybee parasite Varroa jacobsoni

Abstract.

• 1 The reproductve biology of Varroa jacobsoni, whose females infest honeybee brood, was studied in natural and transparent artificial brood cells. These investigations were made under the headings of maturation behaviour and fertilization, and the influence of infestation rate of brood cells on the number of mated females produced per infesting Varroa.
• 2 Mating of Varroa daughters, observed in the transparent brood cells with time-lapse video, occurs just after ecdysis and as soon as they arrive on the faecal accumulation prepared by the mother. Such females are remated for as long as no other freshly moulted daughter arrives on the faecal accumulation.
• 3 The number of spermatozoa stocked in the spermatheca increases with remating, a strong indication for sperm mixing in this species when brood cells contain more than one Varroa foundress.
• 4 The number of daughters per infesting mother decreases at higher rates of infestation per cell, but the proportion of such daughters with a mate rises sharply due to the higher probability of finding a male within multi-infested cells. The number of mated daughters per mother is maximal in cells with two foundress Varroa females.
• 5 The frequency distributions of infesting mites in drone cells are aggregated, and approximate to negative binomial distributions.
• 6 We postulate from the above that the observed non-random infestation by Varroa in drone brood augments the mite's mean reproductive success through the production of a higher number of mated daughters than the corresponding Poisson distributions would.

     

Cannabis sativa: volatile compounds from pollen and entire male and female plants of two variants, Northern Lights and Hawaian Indica

Sixty-eight compounds were identified by coupled gas chromatography and mass spectrometry (GC-MS) in the chemosphere of Cannabis sativa L. pollen and entire male and female plants of two cultivated varieties, Northern Lights and Hawaian Indica. Twenty-one and 28 substances, respectively, were present in pollen of the two forms. To conserve the natural composition of volatiles a delicate headspace method was employed. The two varieties represent different chemotypes which distinguish themselves, in the main quantitatively, in the setup of volatiles from pollen and entire male and female plants. Twenty compounds were monoterpenes, including the five major components: β-myrcene (E)-β-ocimene, terpinolene, β-pinene and limonene; 25 were sesquiterpenes, and the other 23 were of mixed biogenetic origin, including 3-methyl-1-butanol and benzylalcohol which occurred only in pollen; two pyrazines occurred only in Northern Lights females. Besides being of interest in natural products chemistry, the results should have relevance for plant systematics and for the pharmaceutical and technical applications of Cannabis . We demonstrate that the pollen has a distinct chemical character in possessing two exclusive volatiles, while lacking seven compounds occurring in males and females of both variants.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 387–397.     

Indoleacetic Acid Oxidase Activity in Two High-Peroxidase Tomato Mutants

Homogenates of tomato (Lycopersicon esculentum Mill.) tissues oxidize IAA at a rate proportional to their peroxidase activity. Moreover, isoproteins with peroxidase activity catalyze also the oxidation of IAA. Two monogenic recessive mutations, olivacea and monstrosa, are involved in the control of the peroxidase-IAA oxidase activity. In olivacea leaflets this activity is 15 times that of the normal; all the aerial organs of monstrosa show high activities, particularly the midrib. These high activities depend on the enhancement of the organ-specific isoenzymes and on the derepression of the root isoenzyme band C2. This latter peroxidase-IAA oxidase band is present in olivacea and monstrosa leaflets, in monstrosa stems and, less intensely stained, in monstrosa midribs. The reduction in length and weight of mutant organs and their epinastic and geotropic-like behavior are associated with high peroxidase-IAA oxidase activities and with the derepression of the root-specific band C2. These results suggest an important role of the peroxidase-IAA oxidase system in controlling the metric relationships among different organs of the plant. Olivacea and monstrosa are to be viewed as auxin-related mutations controlling the synthesis of a group of proteins related in function.     

The salivary glands of Aparallactinae (Golubridae) and the venom glands of Elaps (Elapidae) in relation to the taxonomic status of this genus

The venom glands of four specimens of Elaps lacteus were examined and found to be structurally similar to the glands of other Elapidae and consequently different from the variable glands of the colubrid Aparallactinae, Lycophidinae and Dispholidinae. The recently proposed removal of Elaps from the Elapidae and its inclusion in the Aparallactinae (McDowell, 1968) is discussed, and the conclusion is reached that Elaps should remain within the Elapidae.     

Morphofunctional patterns in Neotropical felids: species co‐existence and historical assembly

Extant felids are morphologically homogeneous, probably as a result of recent radiation and constraints from their predatory specializations. The Neotropical assemblage comprises 12 of the 41 extant felid species, which occupy all habitats available, with many species coexisting locally. We studied this assemblage on the basis of 31 craniodental variables reflecting morphofunctional variation, measured from 229 specimens representing all 12 species. Multivariate patterns were summarized allowing for phylogenetic covariation. Additional factors (geographical distribution, use of habitat and stratum, and activity pattern) were coded for each species. As expected, body size accounted for most variation, covarying with membership to three deep clades and, to a lesser extent, with large‐scale geographic variation. The species tend to segregate in morphospace plus one or more factors (e.g. habits) that make interspecific overlap in niche space minimal. Using dated phylogenies, biogeographic history, and the fossil record, we reconstructed the historical assembly of the Neotropical felid guild. We found a pattern of successive invasions and speciation in which new lineages occupied previously vacant areas of morphospace, or new species occupied overlapping areas but with contrasting habits. This may be general among antagonistic species of historically structured guilds, and we predict similar patterns in other continents. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 711–724.