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1.
ANDREW F. VAN DEN HURK NIGEL W. BEEBE SCOTT A. RITCHIE 《Medical and veterinary entomology》1997,11(2):177-180
Abstract. In northern Queensland, Australia, three experiments were conducted to determine the response of mosquitoes of the Anopheles farauti complex to CDC traps baited with four attractant combinations: octenol + C02 and light; octenol and light; CO, and light; or C02 and octenol without light. A CDC-modified updraft light-trap was also trialled, but did not significantly enhance collections of An.farauti sensu lato. The combination of light, octenol and C02 caught significantly more An.farauti s.l. (both An.farauti No. 1 and No. 2 sibling species) when compared to C02 and light alone. Only small numbers of the An.farauti complex were captured when CDC traps were baited with octenol alone, i.e. no light or C02 . 相似文献
2.
Actinophage TG1 forms stable lysogens by integrating at a unique site on chromosomes of Streptomyces strains. The phage ( attP TG1 ) and bacterial ( attB TG1 ) attachment sites for TG1 were deduced from comparative genomic studies on the TG1-lysogen and nonlysogen of Streptomyces avermitilis . The attB TG1 was located within the 46-bp region in the dapC gene (SAV4517) encoding the putative N -succinyldiaminopimelate aminotransferase. TG1-lysogens of S. avermitilis , however, did not demand either lysine or diaminopimelate for growth, indicating that the dapC annotation of S. avermitilis requires reconsideration. A bioinformatic survey of DNA databases using the fasta program for the attB TG1 sequence extracted possible integration sites from varied streptomycete genomes, including Streptomyces coelicolor A3(2) and Streptomyces griseus . The gene encoding the putative TG1 integrase ( int TG1 ) was located adjacent to the attP TG1 site. TG1 integrase deduced from the int TG1 gene was a protein of 619 amino acids having a high sequence similarity to φC31 integrase, especially at the N-terminal catalytic region. By contrast, sequence similarities at the C-terminal regions crucial for the recognition of attachment sites were moderate or low. The site-specific recombination systems based on TG1 integrase were shown to work efficiently not only in Streptomyces strains but also in heterologous Escherichia coli . 相似文献
3.
J. W. HARGROVE 《Physiological Entomology》1995,20(3):213-223
Abstract. Ovarian dissections were performed on the tsetse flies Glossina morsitans morsitans Westwood and G.pallidipes Austen of known ages, maintained in the laboratory or on an island in Lake Kariba, Zimbabwe. The lengths ( l 2 and l u ) of the second largest oocyte and of the larva in utero were found to increase approximately exponentially during pregnancy. The length ( l 1 ) of the largest oocyte increased exponentially for about the first 80% of pregnancy. Linear relationships between the log values of l 1 , l 2 and l u in field-caught flies, of unknown chronological age, are consistent with the idea that growth patterns are similar in laboratory, island and open field situations. The egg phase takes up c. 45% of pregnancy in both species, regardless of season and the absolute duration of pregnancy. The changes in the log values of l 1 , l 2 and l u , over the ranges within which they change linearly, can be used to assign flies to their stage of pregnancy. When applied to field data the rule showed that G.pallidipes caught in odour-baited traps, and on a mobile electric net, exhibited major activity peaks shortly before and after parturition. Flies from the trap (but not the net) showed a smaller peak of activity near the middle of pregnancy. The egg and the three larval phases in utero take up c. 45%, 25%, 20% and 10% of pregnancy respectively. 相似文献
4.
Abstract. The anthropophilic malaria mosquito Anopheles gambiae sensu stricto responds to CO2 and human skin emanations. How these odorants affect the behaviour of this mosquito species is studied in an olfactometer. Carbon dioxide is released either as an homogeneous plume or in a turbulent fashion at two different positions from the trap entrance. Anopheles gambiae is deterred from entering a trap with CO2 as the only kairomone, when presented as an homogeneous or turbulent plume. This effect is completely overcome by the addition of skin emanations to the CO2 plume, with a high proportion of mosquitoes found in the trap with skin emanations. Rearrangement of the position of the turbulent CO2 source so that it is 5 cm downwind of the trap entrance overcomes the deterrent effect of CO2 . Carbon dioxide alone, however, does not elicit higher proportions caught compared with clean air. Further studies with the CO2 source positioned 5 cm downwind of the trap entrance show that skin emanations alone result in fewer mosquitoes entering the trap than CO2 + skin emanations. Skin emanations induce more mosquitoes to fly into a trap than a synthetic blend of NH3 + l-lactic acid when both are combined with CO2 . It is concluded that CO2 is a poor kairomone when offered alone and that its presence in the plume at the trap entrance deters mosquitoes from entering. By contrast, when positioned just downwind of the trap entrance, CO2 appears to guide mosquitoes to the vicinity of the trap, where skin emanations then become the principle attractant, causing the mosquito trap entry response. The results of the study have implications for the design of odour-baited traps for this mosquito species. 相似文献
5.
Mihok S 《Bulletin of entomological research》2002,92(5):385-403
New trap designs for tsetse (Glossinidae), stable flies (Muscidae: Stomoxyinae), and horse flies (Tabanidae) were tested in Kenya to develop a multipurpose trap for biting flies. Many configurations and colour/fabric combinations were compared to a simplified, blue-black triangular trap to identify features of design and materials that result in equitable catches. New designs were tested against conventional traps, with a focus on Glossina pallidipes Austen and G. longipennis Corti, Stomoxys niger Macquart, and Atylotus agrestis (Wiedemann). A simple design based on minimal blue and black rectangular panels, for attraction and contrast, with a trap body consisting of an innovative configuration of netting, proved best. This 'Nzi' trap (Swahili for fly) caught as many or significantly more tsetse and biting flies than any conventional trap. The Nzi trap represents a major improvement for Stomoxyinae, including the cosmopolitan species S. calcitrans (Linnaeus), with up to eight times the catch for key African Stomoxys spp. relative to the best trap for this group (the Vavoua). Catches of many genera of Tabanidae, including species almost never caught in traps (Philoliche Wiedemann), are excellent, and are similar to those of larger traps designed for this purpose (the Canopy). Improvements in capturing biting flies were achieved without compromising efficiency for the savannah tsetse species G. pallidipes. Catches of fusca tsetse (G. longipennis and G. brevipalpis Newstead) were higher or were the same as catches in good traps for these species (NG2G, Siamese). Altogether, the objective of developing a simple, economical trap with harmonized efficiency was achieved. 相似文献
6.
F. T. LAST 《The Annals of applied biology》1959,47(4):647-657
Xanthomonas malvacearum spread more rapidly along vascular tissue than into mesophyll when inoculated to the main veins of susceptible cotton leaves. The extent of spread varied with the concentrations of inocula, tissue age and cotton variety.
Increasing concentrations of inocula accelerated the initial spread of disease.
Bacteria spread more rapidly in young leaves than in old—increasing age greatly decreased disease in the mesophyll. The initial invasion was quicker in young leaves of young plants than in young leaves of old plants.
Three types of behaviour, according to the host's reaction, distinguish Knight's resistance factors: ( a ) where X. malvacearum spread extensively along veins and into mesophyll of plants containing factors B3 and B5 ; ( b ) where it was restricted to the point of inoculation in plants containing B 4 , B9 and combinations with B 6m ; and ( c ) where it spread along veins but not appreciably into mesophyll in varieties containing B 2 and B 2 B 3 .
From this and four other different types of tests, factors B2 and B 3 seem to increase mesophyll resistance but only B 2 gives appreciable vascular resistance. Further, the vascular bundles in varieties with B 2 seem to be surrounded by an additional 'barrier' which resists X. malvacearum. 相似文献
Increasing concentrations of inocula accelerated the initial spread of disease.
Bacteria spread more rapidly in young leaves than in old—increasing age greatly decreased disease in the mesophyll. The initial invasion was quicker in young leaves of young plants than in young leaves of old plants.
Three types of behaviour, according to the host's reaction, distinguish Knight's resistance factors: ( a ) where X. malvacearum spread extensively along veins and into mesophyll of plants containing factors B
From this and four other different types of tests, factors B
7.
Fertilization of bean plants grown in perlite with 1 and 3 mM CaCl2 or Ca(NO3 )2 reduced severity of grey mould as compared with control plants or plants fertilized with 5 mM of the compounds. Fertilization with Ca(NO3 )2 reduced severity leaf grey mould and fruit ghost spots of tomato plants grown in perlite by 70 and 45%, respectively. The rate of decrease varied with the position of the fruits on the plants. Leaves from plants treated with calcium or otherwise [KNO3 , (NH4 )2 SO4 ] produced less ethylene than leaves of nontreated plants. Rate of growth of B. cinerea was lower on growth medium prepared from washings from leaves of calcium fertilized plants than from leaves from other treatments. The fertilizer combination Ca(H2 PO4 )2 + CaSO4 (1 and 3 g/kg soil) applied once to tomato plants grown in soil reduced severity of leaf grey mould by 80 % (significant at P = 0.05) but 1–3 g CaSO4 /kg soil only tended to reduce disease severity (30–40 %, not significant) as compared with the control. The compounds CaCl2 and Ca(NO3 )2 increased significantly ( P = 0.05) the growth of B. cinerea on synthetic medium when applied at rates of 1 0–10.0 mM whereas reduction of growth was observed with 0.1 mM of the compounds and of CaSO4 . 相似文献
8.
9.
ield studies were conducted in the Upper Rhine Valley to determine the responses of mosquitoes to CDC traps baited with either CO2 , octenol, light or paired combinations of these. Among eight mosquito species caught, the attractant effect on trap catches was studied in the four most abundant: Aedes vexans, Ae.rossicus, Ae.cinereus and Culex pipiens .
Traps baited only with light or octenol caught few mosquitoes, whereas many were caught by traps baited with CO2 alone or in combination with either of the other candidate attractants. CO2 baited traps, with or without light, caught the most Aedes . The combination of CO2 and octenol attracted most Cx pipiens , but this apparent synergy was not significant.
Using a caged hamster compared to CO2 as bait in a CDC light-trap with only intermittent fan suction, the hamster attracted less mosquitoes than CO2 emitted at a rate of 225 g/h on days 1 and 2, whereas on days 3 and 4 the smell from the hamster's cage became significantly more attractive than this rate of CO2 for all species of mosquitoes. 相似文献
Traps baited only with light or octenol caught few mosquitoes, whereas many were caught by traps baited with CO
Using a caged hamster compared to CO
10.
The uptake of K+ ion was studied in the roots of wheat ( Triuicum aestivum L. cv. GK Szeged) and cucumber ( Cucumis sativus L. cv. Budai csemege) seedlings grown in nutrient solution under nitrogen and sulfate stress conditions. Seedlings pretreated with 1 or 10 m M NaNO3 , absorbed more K+ than those treated with 0.1 m M NaNO3 . However, the posteffect of NaNO3 was considerably influenced by the Na2 SO4 , treatment. The results suggest that, at least partly, a feed-back regulation of K+ uptake may occur. However, due to the high Na+ contents of the roots, a Na+ effect in this process cannot be excluded. The growth and dry matter yields of the roots and shoots were strongly influenced by the SO2− /4 and NO− /3 supply of the plants. Appreciable differences were experienced between wheat and cucumber seedlings. The optimum SO2− /4 concentration of the growth solution for maximal growth varied considerably between the species, and was also different for the roots and the shoots in a given species. 相似文献
11.
Koei Hamana Masaru Niitsu Keijiro Samejima Shigeru Matsuzaki 《FEMS microbiology letters》1988,50(1):79-83
Abstract Besides putrescine, cadaverine, spermidine, spermine and thermospermine, three novel polyamines were detected in a slightly halophilic eubacterium Halococcus acetoinfaciens (IAM 12094, ATCC 25861). These novel polyamines were found to be N -3-aminopropylcadaverine [NH2 (CH2 )3 NH(CH2 )5 NH2 ] and its aminopropyl derivatives: aminopentylnorspermidine [NH2 (CH2 )3 NH(CH2 )3 NH(CH2 )5 NH2 ] and N , N ' -bis(3-aminoprophyl)cadaverine [NH2 (CH2 )3 NH(CH2 )5 NH(CH2 )3 NH2 ]. Aminopropylcadaverine was also detected in two other species, Halococcus agglomeratus (IAM 12095, ATCC 25862) and Halococcus nondenitrificans (IAM 12096, ATCC 25863). 相似文献
12.
Vulnerability of stem xylem to cavitation was measured in 10 species of conifers using high pressure air to induce xylem embolism. Mean values of air pressure required to induce a 50% loss in hydraulic conductivity (φ50 ) varied enormously between species, ranging from a maximum of 14.2±0.6 MPa (corresponding to a xylem water potential of −14.2 MPa) in the semi-arid species Actinostrobus acuminatus to a minimum of 2.3±0.2 MPa in the rainforest species Dacrycarpus dacrydioides . Mean φ50 was significantly correlated with the mean rainfall of the driest quarter within the distribution of each species. The value of φ50 was also compared with leaf drought tolerance data for these species in order to determine whether xylem dysfunction during drought dictated drought response at the leaf level. Previous data describing the maximum depletion of internal CO2 concentration (ci ) in the leaves of these species during artificial drought was strongly correlated with φ50 suggesting a primary role of xylem in effecting leaf drought response. The possibility of a trade-off between xylem conductivity and xylem vulnerability was tested in a sub-sample of four species, but no evidence of an inverse relationship between φ50 and either stem-area specific (Ka ) or leaf-area specific conductivity (K1 ) was found. 相似文献
13.
Zolpidem is a positive allosteric modulator of GABAA receptors with sensitivity to subunit composition. While it acts with high affinity and efficacy at GABAA receptors containing the α1 subunit, it has a lower affinity to GABAA receptors containing α2 , α3 , or α5 subunits and has a very weak efficacy at receptors containing the α5 subunit. Here, we show that replacing histidine in position 105 in the α5 subunit by cysteine strongly stimulates the effect of zolpidem in receptors containing the α5 subunit. The side chain volume of the amino acid residue in this position does not correlate with the modulation by zolpidem. Interestingly, serine is not able to promote the potentiation by zolpidem. The homologous residues to α5 H105 in α1 , α2 , and α3 are well-known determinants of the action of classical benzodiazepines. Other studies have shown that replacement of these histidines α1 H101, α2 H101, and α3 H126 by arginine, as naturally present in α4 and α6 , leads to benzodiazepine insensitivity of these receptors. Thus, the nature of the amino acid residue in this position is not only crucial for the action of classical benzodiazepines but in α5 containing receptors also for the action of zolpidem. 相似文献
14.
The abundance and growth history of larval and juvenile Japanese seaperch Lateolabrax japonicus were investigated in the Chikugo River estuary, upper Ariake Bay, from 1990 to 2000. Growth during the larval period (up to 15 mm standard length, L S , the size at recruitment into the estuary) was backcalculated using sagittal otolith microstructures by the biological intercept method. Growth rates in length declined at body sizes >14 mm L S . High freshwater discharge through the Chikugo River was associated with high temperatures of the upper Ariake Bay where the larvae spend their planktonic life. Mean larval stage duration (days) from hatch to 15 mm ( D 15 ) varied between 48·8 and 76·2 days and was inversely correlated with the estimated mean temperature history [mean daily temperature (° C) experienced by the larvae during the period from hatch to 15 mm, T 15 ]. Mean abundance (number m−2 ) of larvae and juveniles was highest in years when T 15 , D 15 and freshwater discharge were at intermediate levels. Although the abundance was not correlated with either of these variables, an exponential relationship between abundance and D 15 was found when data collected during the highest river discharge years (1990, 1991 and 1998) were excluded. The increase in freshwater discharge through the Chikugo River probably had the potential to enhance or diminish Japanese seaperch recruitment in two ways: 1) it could increase recruitment probability by increasing temperature and larval growth and 2) high river flow also had the potential to decrease the probability of immigration into the river by increasing larval seaward dispersion, predation due to decreased turbidity and starvation due to decreased zooplankton prey abundance in the estuary. 相似文献
15.
Calcium/calmodulin-dependent kinase II (CaMKII) facilitates L-type calcium channel (LTCC) activity physiologically, but may exacerbate LTCC-dependent pathophysiology. We previously showed that CaMKII forms stable complexes with voltage-gated calcium channel (VGCC) β1b or β2a subunits, but not with the β3 or β4 subunits ( Grueter et al. 2008 ). CaMKII-dependent facilitation of CaV 1.2 LTCCs requires Thr498 phosphorylation in the β2a subunit ( Grueter et al. 2006 ), but the relationship of this modulation to CaMKII interactions with LTCC subunits is unknown. Here we show that CaMKII co-immunoprecipitates with forebrain LTCCs that contain CaV 1.2α1 and β1 or β2 subunits, but is not detected in LTCC complexes containing β4 subunits. CaMKIIα can be specifically tethered to the I/II linker of CaV 1.2 α1 subunits in vitro by the β1b or β2a subunits. Efficient targeting of CaMKIIα to the full-length CaV 1.2α1 subunit in transfected HEK293 cells requires CaMKII binding to the β2a subunit. Moreover, disruption of CaMKII binding substantially reduced phosphorylation of β2a at Thr498 within the LTCC complex, without altering overall phosphorylation of CaV 1.2α1 and β subunits. These findings demonstrate a biochemical mechanism underlying LTCC facilitation by CaMKII. 相似文献
16.
Carbon dioxide anaesthesia in rainbow trout: effects of hypercapnic level and stress on induction and recovery from anaesthetic treatment 总被引:2,自引:0,他引:2
The physiological and anaesthetic effects of three different levels of air-saturated and buffered CO2 anaesthesia, P w co 2 =31, 78, or 125 mmHg, were examined in cannulated rainbow trout Oncorhynchus mykiss . Complete anaesthesia (no opercular movements) was not achieved by these hypercapnic levels after 20 min of CO2 exposure. Although increasing P w co 2 reduced the induction times to the early stages of anaesthesia, it also resulted in increasing hyperventilatory, hypoxaemic, and acid-base disturbances. After a 10-min recovery period, while the respiratory acidosis component of the acid-base disturbance was corrected, there was a significant metabolic acidosis. Recovery time was longest in the high Pw co2 treatment where 33% of the fish died. Two additional groups ( P w co 2 =37 and 78 mmHg) were exposed to an acute stress prior to the anaesthetic treatment. Stress reduced the hypoventilatory effects of the low P w co2 treatment, increased the recruitment of anaerobic metabolism, and prolonged recovery time. Although the increase in plasma catecholamines elicited by the stress was small relative to the response obtained with the anaesthetic, stress prior to CO2 anaesthesia impaired the efficiency of the treatment. Overall, our results suggest that P w co2 levels above 37 mmHg and/or stress prior to the anaesthesia impair the efficiency of air-saturated and buffered CO2 anaesthesia by exacerbating the hypoxaemic effects of the hypercapnic treatment. 相似文献
17.
R. J. A. Atkinson B. Pelster †‡ C. R. Bridges † A. C. Taylor § S. Morris † 《Journal of fish biology》1987,31(5):639-659
Observations have been made on the mode of burrow construction in the snake blenny, Lumpenus lampretaeformis , under laboratory conditions. It appears that head probing and lateral oscillations of the body are principally responsible for the excavation of the burrow which is completed within 24 h. The burrow structure has been analysed in detail, showing a mean depth of 7.2 cm with a maximum observed length of 73 cm, with most systems between 20 and 35 cm in length. Initially linear burrows with two openings are usually provided with a small side tunnel, giving the system a characteristic Y-shape.
Burrow irrigation was investigated for the first time in L. lampretaeformis. The mean duration of burrow irrigation, by flexions of the tail of the fish, was 21 s with over 13 min h−1 spent in irrigating the burrow. The mean water displacement per irrigation period was 3.1 ml. The PO 2 and PCO 2 were measured in both surface water and within the burrow system of L. lampretaeformis. Surface water values for PO 2 were high (> 150 Torr) and PCO 2 low (<0.4 Torr). Hypoxic and hypercapnic conditions were measured in the burrow system itself, with PO 2 values ranging between 57 and 129 Torr and PCO 2 rising to > 1.3 Torr in some burrows.
A comparative study of Cepola rubescens burrows indicated similar surface water PO2 and PCO 2 values as in L. lampretaeformis. Burrow water PO 2 values ranged between 60 and 94 Torr, with PCO 2 values as high as 1.5 Torr being recorded. These results are discussed in relation to the adaptation of both species to a burrowing lifestyle. 相似文献
Burrow irrigation was investigated for the first time in L. lampretaeformis. The mean duration of burrow irrigation, by flexions of the tail of the fish, was 21 s with over 13 min h
A comparative study of Cepola rubescens burrows indicated similar surface water PO
18.
Effects of carbon dioxide, acetone and 1-octen-3-ol on the flight responses of the stable fly, Stomoxys calcitrans, in a wind tunnel 总被引:1,自引:0,他引:1
Abstract. The flight behaviour of Stomoxys calcitrans (L.) in odour plumes containing carbon dioxide, acetone or l-octen-3-ol was assessed from video recordings. A downwind bias was evident in clean air, whereas all three test chemicals elicited upwind anemotaxis. Response thresholds were ∼0.006% for CO2, between 0.001 and 0.01 μg/l for acetone, and ∼0.0002 u.g/1 for l-octen-3-ol. Sinuosity (° cm-1 ) and angular velocity (° s-1 ) increased with C02 concentration, but velocity (cm s"1 ) decreased. Similar, but less clear effects were observed for acetone and l-octen-3-ol. 相似文献
19.
Koei Hamana Shigeru Matsuzaki Masaru Niitsu Keijiro Samejima 《FEMS microbiology letters》1990,66(1-3):35-38
Abstract Two novel polyamines were found as major polyamines of Thermoleophilum album and Thermoleophilum minutum , which are Gram-negative eubacteria obligate for thermophily and n -alkane substrates. They were identified as tertiary branched tetraamines, N4 -aminopropylnorspermidine ( tris (3-aminopropyl)amine) [NH2 (CH2 )3 N-((CH2 )3 NH2 )(CH2 )3 NH2 or N(CH2 CH2 CH2 NH2 )3 ] and N4 -aminopropylspermidine [NH2 (CH2 )3 N((CH2 )3 NH2 )(CH2 )4 NH2 ] by high-performance liquid chromatography and gas chromatography-mass spectrometry. 相似文献
20.
HEWLETT PS 《The Annals of applied biology》1948,35(1):84-93
The problem of whether a given amount of active ingredient is more effectively applied in concentrated or dilute form is discussed. If y is percentage mortality and x 1 and x 2 are respectively log-concentration of active ingredient and log-volume (or deposit) of insecticide applied, y may be regarded as a uniform, continuous function of x 1 and x 2 . The amount of active ingredient is constant, i.e. x 1 + x 2 = k , so that
dx/dx1 =−dy/dx2 =δy/δx1 −δy/δx2
Probit mortality, Y , can be substituted for y in (4). Thus, whether an active ingredient is better applied in concentrated or dilute form depends on the relative magnitudes of ∂ y /∂ x1 and ∂ y /∂ x 2 , or of ∂ Y /∂ x 1 and ∂ Y /∂ x 2 . Equation (4) is true whenever an insecticide consists of an active ingredient in a diluent, whatever the dosage-mortality relationship. Previous work is discussed in the light of (4) and its probit form, and it appears that the concentration at which an active ingredient is best applied can depend upon the nature and quantity of the active ingredient, and the method of application of the spray. There may be other facto*** The probit form of (4) is applied to the probit plane and confirmed experimentally. Flour beetles, Tribolium castaneum Herbst were sprayed with pyrethrins in Shell oil P 31, and it was found that ∂ Y /∂ x 1 > ∂ Y /∂ x 2 , so that a given quantity of pyrethrins was more toxic in concentrated solution than in dilute. 相似文献
dx/dx
Probit mortality, Y , can be substituted for y in (4). Thus, whether an active ingredient is better applied in concentrated or dilute form depends on the relative magnitudes of ∂ y /∂ x