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PubMed1991

[Impact of the use of larvivorous fish Poecilia reticulata on the transmission of malaria in FIR of Comoros].

Field tests were conducted in the Grande Comore Island, Federal Islamic Republic of Comoros, in order to evaluate the potential of the larvivorous fish Poecilia reticulata for the control of the malaria vector Anopheles gambiae s.s. Due to the high permeability of soil, Anopheles breeding sites in all island occurs only in the man-made water reservoirs. The study was carried out from November 1987 to November 1988 within a framework of a malaria and filariasis control programme, supported by WHO and UNDP in collaboration with the Government of the FIR of Comoros. All larval breeding places of An. gambiae existing in the village of Hantsambou were recorded (59 ablutions basins and 61 cisterns) and provided initially with 3-5 specimens of P. reticulata/m3 in November 1987, after the importation of the larvivorous species from Mayotte Island. The percentage of breeding places positive for An. gambiae decreased from 41% to 6% after one year. Pyrethrum spray catch showed a reduction of indoor resting density from 5.5 to 0.3, while the ma value, number of Anopheles bites/man/night, obtained by night-biting catches, decreased from 6.3 to 1.2. At the same time of the reduction of entomological indices parasite index for P. falciparum and spleen rate drop steadily in 5-9 years school children. The tested vector control method, well accepted by the community, could be implemented in malaria control through primary health care, being the ecological conditions in the entire island very peculiar.

Animals↗
PubMed1991

[Antibody levels against circumsporozoitic protein of Plasmodium falciparum and their use as epidemiological indicators of malaria transmission in FIR of Comoros].

Epidemiological survey on prevalence of Plasmodium falciparum anti-circumsporozoite antibodies (Ab-CS) was carried out in 21 villages of Comoros FIR, at the beginning of 1988 rainy season. Evaluation of anopheline indoor resting densities was also carried out at the same time. Frequencies of antibody-positive subjects vary considerably in the different villages, according to the Anopheles gambiae and A. funestus densities per room, which are determined by ecological factors. Ab-CS prevalence varies in the sample population from 5.5% in 3-4 years children to 40% in those of 5 years. Starting from 6-7 years group, prevalence increased steadily reaching a plateau by 30 years of age. The detection of Ab-CS levels in a sample population is a good tool to evaluate malaria transmission levels, especially where the epidemiological situation does not allow a reliable entomological evaluation.

Adolescent↗
PubMed1995

Induced oleoresin biosynthesis in grand fir as a defense against bark beetles.

Grand fir (Abies grandis) saplings and derived cell cultures are useful systems for studying the regulation of defensive oleoresinosis in conifers, a process involving both the constitutive accumulation of resin (pitch) in specialized secretory structures and the induced production of monoterpene olefins (turpentine) and diterpene resin acids (rosin) by nonspecialized cells at the site of injury. The pathways and enzymes involved in monoterpene and diterpene resin acid biosynthesis are described, as are the coinduction kinetics following stem injury as determined by resin analysis, enzyme activity measurements, and immunoblotting. The effects of seasonal development, light deprivation, and water stress on constitutive and wound-induced oleoresinosis are reported. Future efforts, including a PCR-based cloning strategy, to define signal transduction in the wound response and the resulting gene activation processes are delineated.

Amino Acid Sequence↗
PubMed1981

Residues of chlorpyrifos-methyl in balsam fir foliage, forest litter, soil, stream water, sediment and fish tissue after double aerial applications of Reldan.

Chlorpyrifos-methyl was applied twice at 70 g A.I./ha by means of a fixed-wing aircraft to a mixed coniferous forest near Allardville, New Brunswick. Residue in balsam fir foliage was highest (1 ppm wet wt) 1 hr after spraying and rapidly declined to about 30% within 1 day, but persisted at a very low level (0.03 ppm wet wt) for 125 days. Current year's foliage contained a higher level of residue than old foliage. Chlorpyrifos-methyl persisted longer in forest litter than in soil. After 125 days, trace amounts (less than 6 ppb wet wt) were still found in litter but were not detected in soil. In stream water the residue dissipated very rapidly; more than 90% disappeared 3 hours after the second application and were not detected after 4 days. Low-level residue (less than 0.1 ppm wet wt) was present in the sediment and persisted for 10 days. Although brook trout and slimy sculpin captured in the stream within 3 days of the second application contained residues (less than 0.05 ppm fresh wt) none were detected in any fish captured, 9 and 47 days later.

Animals↗
PubMed2000

Intoxication with huperzine A, a potent anticholinesterase found in the fir club moss.

BACKGROUND: Herbs from Lycopodium are generally reputed to be nontoxic and are occasionally used for preparing a salubrious tea. In Europe, the common Lycopodium clavatum can be easily confused with Lycopodium selago, the fir club moss. CASE REPORT: We report 2 patients who drank a tea, erroneously prepared from dried herbs of Lycopodium selago, which resulted in sweating, vomiting, diarrhea, dizziness, cramps, and slurred speech. These symptoms were suggestive of a cholinergic mechanism. To elucidate the active principle, aqueous extracts of Lycopodium selago were checked for their suspected anticholinesterase activity using human erythrocytes as an enzyme source in a modified Ellman assay. The extracts did exhibit significant anticholinesterase activity. The anticholinesterase(s) were most effectively extracted with dichloromethane and isolated by high-performance liquid chromatography. The major compound with anticholinesterase activity co-chromatographed with authentic huperzine A, but had a 2-3-fold higher inhibitory potency than the racemic standard. The amount of huperzine A found in the Lycopodium selago sample used for the tea preparation was calculated to be sufficient for a relevant acetylcholinesterase inhibition. CONCLUSION: The signs and symptoms of Lycopodium selago poisoning are consistent with the anticholinesterase activity of huperzine A and should favorably respond to atropine therapy. This report demonstrates once more that laymen should not be encouraged to gather their remedies from "Mother Nature" without advanced botanical knowledge.

Alkaloids↗
PubMed2005

Differentiation of terminal latewood tracheids in silver fir trees during autumn.

BACKGROUND AND AIMS: The differentiation of terminal latewood tracheids of silver fir (Abies alba) trees grown in Slovenia was investigated in autumn/winter 2001/2002. METHODS: The experimental trees were divided into three groups: one with narrow annual rings, width less than 1 mm; one with annual ring widths between 1 and 4 mm; and one group with broad rings larger than 4 mm. The differentiation of terminal latewood tracheids was investigated by light-, electron- and UV-microscopy in tissues sampled in October and November 2001 and March 2002. KEY RESULTS: In the middle of October, cambial divisions did not occur any more in any of the trees. In trees with narrow annual rings, cell wall deposition as well as lignification were completed in terminal latewood tracheids at this date, whereas in trees with annual ring widths of more than 1 mm these processes still continued. Electron microscopy as well as UV microscopy revealed an unlignified inner S(2) layer and the absence of S(3) and warty layers. With increasing distance from the cambium, wall formation and lignification gradually appeared to be completed. Samples of all trees taken in the middle of November only contained differentiated terminal latewood tracheids. At the structural and lignin topochemical level, November and March samples showed completed differentiation of walls of terminal latewood tracheids. CONCLUSIONS: In trees with broader annual rings, the final steps of differentiation of the youngest latewood tracheids near the cambium still continued during autumn, but were finished prior to winter. It was concluded from structural observations that duration of cambial activity is longer in trees with broad annual rings than in trees with narrow rings.

Abies↗
PubMed2003

Mapping of quantitative trait loci controlling adaptive traits in coastal Douglas fir. III. Quantitative trait loci-by-environment interactions.

Quantitative trait loci (QTL) were mapped in the woody perennial Douglas fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) for complex traits controlling the timing of growth initiation and growth cessation. QTL were estimated under controlled environmental conditions to identify QTL interactions with photoperiod, moisture stress, winter chilling, and spring temperatures. A three-generation mapping population of 460 cloned progeny was used for genetic mapping and phenotypic evaluations. An all-marker interval mapping method was used for scanning the genome for the presence of QTL and single-factor ANOVA was used for estimating QTL-by-environment interactions. A modest number of QTL were detected per trait, with individual QTL explaining up to 9.5% of the phenotypic variation. Two QTL-by-treatment interactions were found for growth initiation, whereas several QTL-by-treatment interactions were detected among growth cessation traits. This is the first report of QTL interactions with specific environmental signals in forest trees and will assist in the identification of candidate genes controlling these important adaptive traits in perennial plants.

Genetic Linkage↗
PubMed2003

Lethal and sublethal effects of a neem-based insecticide on balsam fir sawfly (Hymenoptera: Diprionidae).

Lethal and sublethal effects of Neemix 4.5 EC, a commercial neem preparation, on balsam fir sawfly, Neodiprion abietis (Harris), were determined in the laboratory. Larval mortality of N. abietis increased in a concentration-dependent manner, and lethal time decreased with increasing Neemix 4.5 EC concentration. Fifty percent of the larvae died after 4.6 d at a concentration of 90 ppm azadirachtin (AZA) and 12.3 d at a concentration of 0.08 ppm. Neemix 4.5 EC showed some deterrent effects to feeding site selection on N. abietis larvae at high concentrations, but not at low concentrations. Strong reduction of food intake by N. abietis larvae after exposure to Neemix 4.5 EC was demonstrated by significant reduction of frass production. Larvae fed on Neemix 4.5 EC-treated foliage at 90 ppm AZA produced only 16% as much frass as that produced by larvae fed on control foliage (0 ppm). Neemix 4.5 EC at a concentration of 0.08 ppm AZA retarded larval and pupal development. Sublethal doses significantly reduced pupal weight and adult emergence, although the sex ratio of N. abietis adults was not affected. Results indicate that sublethal effects of Neemix 4.5 EC on N. abietis may contribute greatly to the overall field efficacy.

Abies↗
PubMed2003

Laboratory and field evaluation of tebufenozide, diflubenzuron, and Bacillus thurengiensis var. kurstaki for suppression of Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough)) in Idaho: a case study.

The insect growth regulator tebufenozide (MIMIC 2LV) was tested to examine its impact on the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough) (Lepidoptera: Lymantriidae). Laboratory tests gave an estimated concentration of 1.26 ppm of the compound to achieve 50% population mortality (LC50) for second-instar O. pseudotsugata. At the highest concentration tested, tebufenozide resulted in significant larval mortality within 7 d with an estimated time to 50% population mortality (LT50) of 6.3 d. A field comparison oftebufenozide with diflubenzuron (Dimilin 4L) and Bacillus thurengiensis var. kurstaki (Btk, FORAY 48B) was also conducted. There was no significant difference in larval mortality within field plots that were treated with diflubenzuron (42.4%) or Btk (44.8%). Larval mortality in the tebufenozide-treated plots (56.8%) was also similar to the mortality in the diflubenzuron and Btk treatments. All three treatments resulted in more larval mortality than that measured in untreated controlplots (11.2%). Both tebufenozide and diflubenzuron treatments resulted in significantly more mortality (55.0% and 40.0%, respectively) to larvae-fed treated foliage 3 wk after application than was measured for larvae-fed foliage from untreated trees (11.0%). There was no significant difference among the treatments in the percentage of host trees in the overstory that sustained >25% defoliation, and all three treatments resulted in less defoliation than was measured in the control plots. There was no significant difference among the treatments in the percentage of host trees in the understory that sustained >25% defoliation.

Animals↗
PubMed1986

An effect of gravity on bud-burst in balsam fir.

Bud-burst on first order lateral branches of Abies bafsamea L. (balsam fir) was delayed when the branches were rotated 180 degrees about their long axis. This was not a consequence of injury caused by the treatment because buds rotated 180 degrees on inverted plants flushed at the same time as the controls, whereas flushing of all other buds was delayed. Buds thus appear to be more vigorous when maintained in the same orientation to gravity in which they are formed and the site of gravitational stimulus perception appears to be the bud itself. Except on the leading shoot, leaves from inverted buds turned so that their adaxial surface faced upward, unless there was intense illumination from below. However, both anisophylly and positioning of leaves on lateral shoots were apparently predetermined because the shorter, more forward pointing leaves appeared below the longer distichous leaves on shoots from inverted buds. Shoots with normally oriented leaves appeared the next season.

Journal Article↗
PubMed1986

Effects of pretreatment conditions on ammonium and nitrate uptake by Douglas-fir seedlings.

Effects of pretreatment solutions containing varying concentrations of calcium, potassium, ammonium and nitrate were evaluated by measuring fluxes of the same ions during a subsequent 4-hour uptake by Douglas-fir seedlings. Maximal rate of ammonium uptake (11 microeq g(-1) root dry weight h(-1)) was about 5 times faster than that of nitrate (2 microeq g(-1) root dry weight h(-1)). Ammonium uptake was most rapid after pretreatment with low potassium levels and was unaffected by ammonium pretreatment. Nitrate uptake was most rapid after pretreatment with high levels of nitrate and low levels of potassium. Calcium uptake was greater when nitrate replaced ammonium as the N source. High calcium pretreatment levels depressed subsequent calcium uptake or resulted in calcium release in both ammonium and nitrate experiments. Potassium efflux occurred with both N sources, but the release was less during nitrate uptake than during ammonium uptake. Efflux of potassium is probably associated with the high potassium status of the seedlings and the exchange between potassium and other cations. High levels of potassium in the pretreatment solutions enhanced potassium efflux and caused a reduction in the subsequent rates of uptake of both ammonium and nitrate. Length of pretreatment and seedling size generally did not affect uptake rates.

Journal Article↗
PubMed1992

Physiology and morphology of Douglas-fir rooted cuttings compared to seedlings and transplants.

Cuttings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) from three open-pollinated families were rooted in two types of tray, and then grown for 1.5 years in a bareroot nursery. During their second winter they were sampled periodically and tested for cold hardiness, dormancy status, root growth potential and various morphological characteristics. Two-year-old seedlings and transplants were tested concurrently for comparison. Rooted cuttings, seedlings and transplants cold hardened at similar rates during early winter, achieving the same level of midwinter hardiness (LT(50) = -18 degrees C) in early January. However, rooted cuttings remained hardier later into the spring than did seedlings or transplants. Rooted cuttings exhibited deeper dormancy in early winter than seedlings or transplants but these differences disappeared after January. Root growth potentials of all three stock types remained above threshold values established for transplants throughout winter. Rooted cuttings had greater stem diameter, higher stem diameter to height ratio, and greater root weight than either seedlings or transplants. This may reflect lower growing densities for the rooted cuttings. Root/shoot ratios of rooted cuttings were greater than for seedlings and similar to those of transplants. Rooted cuttings also had deeper and coarser root systems, which probably reflects lack of wrenching at the nursery.

Journal Article↗
PubMed1992

Ex vitro photosynthetic activity in plantlets of tissue-cultured Douglas-fir.

Plantlets of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) had lower rates of net CO(2) uptake and higher rates of root respiration than greenhouse-grown seedlings. They also had a lower photosynthetic efficiency at high photosynthetic photon flux density, and exhibited significant depression of CO(2) uptake under water stress. The ability of plantlets to utilize high irradiance and to photosynthesize under conditions of water stress was enhanced by the presence of many roots. Carbon dioxide uptake rate increased with increasing root number, and decreased as the needle surface area/root surface area ratio decreased. High root number, low needle surface area/root surface area ratio, and elongated roots were associated with low apparent rates of shoot and root respiration.

Journal Article↗
PubMed1993

Effects of foliar nitrogen concentration on photosynthesis and water use efficiency in Douglas-fir.

Leaf-level physiological processes were studied in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to determine whether apparent increases in stand-level water use efficiency (WUE) observed in response to nitrogen (N) fertilization were attributable to foliar N effects on carbon fixation rates or on stomatal control of water loss. Photosynthesis and transpiration were measured at different light intensities and ambient CO(2) molar fractions and comparisons were made between current-year shoots with average foliar N concentrations of 1.58% (High-N) and 1.25% (Low-N). Photosynthetic rates and foliar N concentrations were positively correlated. In response to light, photosynthesis and stomatal conductance were closely coupled and a similar coupling was observed in response to different ambient CO(2) concentrations. Partitioning the photosynthetic responses into mesophyll and stomatal components indicated that foliar N altered mesophyll conductance but not stomatal control of water loss. High-N shoots had significantly greater rates of photosynthesis and transpiration than Low-N shoots and, as a result, instantaneous WUE did not differ significantly between High-N and Low-N shoots.

Journal Article↗
PubMed1993

Three dimensional distribution of needle and stem surface area in a Douglas-fir.

The distribution of needles and branches in the crown of a 14-m tall Douglas-fir was investigated for the purpose of developing a three-dimensional structure for use with radiation transfer models. We found a linear relationship between the basal area of main branches originating at the bole and the total one-sided planimetric surface area of the foliage attached to each branch. A similar linear relationship was found between the branch basal area and the mass of stem material on the branch. Total silhouette area (needles plus branch material) did not vary significantly horizontally along the branch length, but stem surface area declined linearly from near the bole to the branch tip. Needle surface silhouette area and leaf area index increased along the main branch from near the bole to the branch tip. Silhouette leaf area (STAR) did not vary along the main branch. The needle area density (NAD) (m(2) m(-3)) was calculated for each of the lower 11 whorls; the vertical distribution of NAD increased from the base of the bole to the top of the crown.

Journal Article↗
PubMed1994

Maturation in Douglas-fir: I. Changes in stem, branch and foliage characteristics associated with ontogenetic aging.

Two experiments were conducted to characterize changes associated with ontogenetic aging in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and to identify possible maturation "markers" for this species. In the first experiment (Experiment 1), scions of ages 1, 4 and 9 years were collected from four seed zones in field progeny tests and grafted onto 1-year-old rootstocks. In Experiment 2, scions from five full-sib families of ages 1 and 10 years were collected from one progeny test and similarly grafted. Grafts for both experiments were planted in the field in a completely randomized design. The grafts were measured after two and six growing seasons. In Experiment 1, graft diameter, number of terminal bud flushes per year, number of branches, and branch length decreased with age. Plagiotropic angle and needle weight increased. All variables except needle length had a significant age x seed zone interaction. After 6 years, internodal stem diameters, numbers of nodal and internodal branches, and length and diameter of internodal branches decreased with age, and there were age x seed zone interactions with most variables. In Experiment 2, graft height and diameter, number of flushes, number and size of lateral branches, needle length and weight decreased with age. After 6 years, height and diameter, size and number of nodal and internodal branches, and leaf chlorophyll concentration (measured in April) decreased, but there were relatively few age x family interactions. An analysis based on traits that were significantly affected by age, but that did not interact with seed zone or family, indicated that main stem diameter, nodal branch length and nodal branch diameter were the most consistent and reliable maturation markers.

Journal Article↗
PubMed1994

Adaptive significance of intermittent shoot growth in Douglas-fir seedlings.

We tested the hypothesis that intermittent (lammas) shoot growth in Douglas-fir (Pseudotsuga menziesii var menziesii (Mirb.) Franco) seedlings from dry regions of southwest Oregon is adaptively significant. Seedlings from open-pollinated families (160 total) from two inland (dry) and two coastal (wet) sources were grown under either well-watered or intermittent drought conditions (temporary drought followed by rewatering) for two growing seasons. In the first growing season, the results supported the hypothesis: the frequency of a second flush was genetically controlled (although weakly, h(f) (2) </= 0.34); more seedlings, on average, from inland families than from coastal families displayed a second flush; and seedlings from inland families were more responsive to the intermittent drought regime in terms of increased frequency of a second flush (relative to the frequency in the well-watered regime). During the second growing season, the intermittent drought treatment did not promote intermittent shoot growth, although inland and coastal families had different patterns of shoot growth that reflected adaptations to soil water availability. We conclude that inland families have adapted to dry summers and short growing seasons by relying predominantly on predetermined growth for seedling height increment after the first growing season. In response to wetter and generally longer growing seasons, however, coastal families have developed a less regulated pattern of shoot extension and rely more on free growth.

Journal Article↗
PubMed1994

Effects of short-term ozone exposure and soil water availability on the carbon economy of juvenile Douglas-fir.

Effects of ozone and soil water availability on partitioning and translocation of assimilates were studied in three-year-old Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings exposed, in separate experiments, to 0 and 106 or 0 and 514 micro g m(-3) ozone for 8 h day(-1) for 9 days. The dynamics of carbon from assimilated (14)CO(2) were followed. No interactions between ozone and soil water content were observed. Total net uptake of carbon was reduced by low soil water content, but was unaffected by ozone. Both ozone and low soil water content increased the amount of (14)C-photosynthates retained in the current-year needles. Total starch content in old and current-year needles was unaffected by ozone, but was reduced by low water availability. Translocation of carbon to the root-soil compartment was additively affected by ozone and low soil water content. The results suggest that dry periods in summer combined with high ozone concentrations cause the greatest reduction in the supply of carbon compounds to the root-soil compartment.

Journal Article↗