Decreased Histamine-Stimulated Phosphoinositide Hydrolysis in the Cerebral Cortex of a Rat Line Selectively Bred for High Alcohol Preference

This study sheds light on the comparative analysis of agonist-stimulated phosphoinositide (PI) hydrolysis in the cerebral cortex of alcohol-naive rats from established lines selectively bred for low alcohol preference (LAP) and high alcohol preference (HAP). The effect of histamine (1.0 mM), but neither norepinephrine (0.1 mM) nor carbachol (0.5 mM), on PI hydrolysis was significantly reduced in HAP rats (0.4 +/- 5.0 fmol/mg protein [3H]inositol phosphates formed over basal) compared with LAP rats (25.5 +/- 10.0 fmol/mg protein). The contents of monoamines (dopamine, norepinephrine, and serotonin) and histamine in the cerebral cortex did not significantly differ between LAP and HAP rats, nor did the contents of their metabolites, except 3-methoxy-4-hydroxyphenylglycol (one of the metabolites of norepinephrine) and N(tau)-methylhistamine, which was not detected in our system. The histamine stimulatory effect was unchanged in the cerebral cortex of an intact Wistar rat that was treated with intraperitoneal injection of alcohol (1.0 g/kg once per day for 14 days). The results of the current study indicate that the decrease in the histamine effect on PI hydrolysis in HAP rats might be attributed to that particular rat line.     

Promotion of Female Strobili Flowering and Seed Production in two Japanese Pine Species by 6-Benzylaminopurine (BAP) Paste Application in a Field Seed Orchard

Treatment with 6-benzylaminopurine (BAP) to promote the flowering of female strobili and to increase seed production in a seed orchard was examined at different times of conebud differentiation for Japanese red pine (Pinus densiflora) and Japanese black pine (P. thunbergii), from late August to mid-September 1998. BAP was mixed with lanolin and Vaseline to prepare a paste (BAP, 2000 mg/L), which was used for a terminal bud treatment and also applied in a girdling treatment. The BAP treatment in early September transformed lateral buds on lower branches that would have normally differentiated as male strobili into female strobili. The highest percentages of female flowering branches were 21.1% (red) and 40.5% (black) produced by the terminal bud treatment, while control branch percentages were 5.0% and 7.1%, respectively. Girdling combined with BAP treatment further promoted female flowering branches to 32.3% (red) and 64.3% (black), while those of controls were 8.3% and 9.9%, respectively. Moreover, the numbers of female strobili per female flowering branch were 6 to 11-fold greater than controls. Mature seed cones were harvested in October two years later from which full seeds with a high germination ratio were recovered. Use of BAP treatment is thus highly effective for enhancing seed production in seed orchards of these two pine species.     

Design and analysis of multiple choice feeding preference data

Traditional analyses of feeding experiments that test consumer preference for an array of foods suffer from several defects. We have modified the experimental design to incorporate into a multivariate analysis the variance due to autogenic change in control replicates. Our design allows the multiple foods to be physically paired with their control counterparts. This physical proximity of the multiple food choices in control/experimental pairs ensures that the variance attributable to external environmental factors jointly affects all combinations within each replicate. Our variance term, therefore, is not a contrived estimate as is the case for the random pairing strategy proposed by previous studies. The statistical analysis then proceeds using standard multivariate statistical tests. We conducted a multiple choice feeding experiment using our experimental design and utilized a Monte Carlo analysis to compare our results with those obtained from an experimental design that employed the random pairing strategy. Our experimental design allowed detection of moderate differences among feeding means when the random design did not.     

Biosynthetic maturation of the corpus allatum of the female adult medfly,Ceratitis capitata,and its putative control

The major juvenile hormone (JH) homolog synthesized in vitro by the adult female Medfly (Ceratitis capitata) corpus allatum (CA) is JHB(3), with JH-III the minor homolog. Methyl-incorporation in vitro in post-eclosion virgin females is age-dependent. Basal activity occurs during the first four days post-eclosion and increases significantly thereafter, peaking at five days. Biosynthetic maturation of the mated female CA is delayed by one day and reduced considerably. The delayed response may be due to direct cerebral or neural inhibition. Synthetic Drosophila melanogaster sex peptide depresses JH biosynthesis by the Medfly female CA in vitro. Male-derived accessory gland peptides of the Medfly are transferred to the female during mating and a Medfly SP-analog may be responsible for down-regulation of JH synthesis by the CA in mated Medfly females. Mevinolin, an inhibitor of the mevalonate pathway, significantly reduces the biosynthesis of JHB(3), while farnesoic acid, a proximate precursor of JHIII, significantly stimulates the biosynthesis of both JHB(3) and JHIII in vitro.     

Physiology and endocrinology of zinc accumulation during the female squirrelfish reproductive cycle

Females of the squirrelfish family (Holocentridae) accumulate higher levels of hepatic zinc than any other studied animal. This accumulation is accompanied by high expression of the zinc-binding protein, metallothionein (MT), and is strongly correlated to the onset of sexual maturity. In an attempt to further characterize the timeframe of this accumulation, and to possibly discern any potential mediators, we examined the physiology and endocrinology of the yearly reproductive cycle of mature female squirrelfish. There are two separate reproductive events during the year in December-January and again in March-April, as evidenced by peaks in ovarian growth, VTG production, steroid levels, zinc accumulation and redistribution. Increased hepatic zinc seems to be preceded by a necessary increase in MT, but this was not clearly correlated to plasma 17beta-estradiol, testosterone, or progesterone levels. The plasma zinc protein vitellogenin (VTG) is one, but probably not the predominant, vehicle for the transport of hepatic zinc to the ovary.     

Apoptosis in zebrafish development

Apoptosis (programmed cell death) is important in normal biological processes and in pathogenesis in vertebrates. This review focuses on some of the prominent features of apoptosis during fish development. Caspases and other apoptosis-regulating genes have been cloned from zebrafish (Danio rerio) and other fish species. Elucidation of in vivo functions of apoptosis is focused on development, morphogenesis and sex differentiation. In an attempt to elucidate cause and effect relationships between caspase and development, transgenic zebrafish overexpressing procaspase-3 were generated. Stress-induced apoptosis in zebrafish embryos can be monitored by whole mount TUNEL staining and caspase assay. Thus, zebrafish is a useful experimental model animal for investigation of apoptosis in vivo.     

L-lactic acid: a human-signifying host cue for the anthropophilic mosquito Anopheles gambiae

Using a dual-choice olfactometer, the role of L-lactic acid was investigated in relation to host-seeking and selection by female Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) mosquitoes in a Y-tube bioassay. L-lactic acid alone was not attractive, but it significantly augmented the attractiveness of CO2, skin odour and skin-rubbing extracts from humans and other vertebrates. Comparing the left and right index fingers of the same person, one could be made more attractive than the other by adding L-lactic acid to the air stream over that finger. The difference in L-lactic acid concentration between the two air streams offered to the mosquitoes fell within the natural range of variation emanating from a human hand, suggesting that L-lactic acid modulates intraspecific host selection by An. gambiae. Analysis of skin rubbings from various vertebrates (carnivores, chickens, primates, rodents, ungulates) indicated that humans have uniquely high levels of L-lactic acid on their skin. Tests with extracts of skin rubbings from cows and humans, with and without added L-lactic acid, suggest that naturally lower levels of L-lactic acid contribute to the lesser attractiveness of non-humans to An. gambiae s.s.     

A male and hermaphrodite specific RAPD marker for papaya ( Carica papayaL.)

The random amplified polymorphic DNA (RAPD) technique was used to determine the sex of a dioecious species, Carica papaya L., with three sex types, male, female and hermaphrodite. A 450 bp marker fragment, named PSDM(Papaya Sex Determination Marker), exists in all male and hermaphrodite plants but not in the female plants so far analyzed. The DNA sequence of PSDM exhibited no significant similarity to previously reported sequences. A sequence-characterized amplified region (SCAR) marker, SCARps, was developed from PSDM to determine the sex of papaya. Southern hybridization, using PSDM as a probe, showed that PSDM exists in the male and hermaphrodite genomes, but not in the female genome. This result strongly suggests that PSDM is located on the chromosome region that is specific to the male and the hermaphrodite. SCARps is a suitable marker for the precise and rapid diagnosis of sex in papaya. Received: 1 February 2001 / Accepted: 22 May 2001     

Detection of short pure-tone stimuli in the noctuid ear: what are temporal integration and integration time all about?

The interception of a pheromone filament induces flying moths to surge briefly nearly straight upwind; in the absence of pheromone moths cease upwind progress and zigzag crosswind. We tested males of the almond moth, Cadra cautella (Lepidoptera, Pyralidae), in a low-turbulence wind tunnel in wind velocities of 20, 40 and 80 cm s⁻¹. A mechanical pulse generator was set to produce plumes either with same pheromone pulse frequency (pulse generation frequency of 2.9 Hz, interpulse distances from 7 cm to 28 cm) or plumes with same interpulse distance across the three wind velocities (interpulse distance of 14 ± 2 cm, pulse generation frequency of 1.7–5.0 Hz). In plumes of similar pulse frequency, the faster the speed of the wind the slower the ground speed of flight. However, in plumes of similar interpulse distance, ground speed remained relatively constant independent of the wind speed. A `realized' frequency of pulse interception for males flying along the various combinations of pulse frequencies and wind velocities was calculated using the males' average airspeed and the spatial distribution of pheromone pulses in the plume. Realized frequency of pulse interception ranged from 1.3- to 3.0-fold higher than the frequency of pulse generation. The flight tracks of males reflected the regime of realized pulse interception. These results suggest that upwind flight orientation of male C. cautella to pheromone in different wind velocities is determined by the flux of filament encounter. Accepted: 3 September 1997