Abstract The effects of relative humidity (RH) on cocoon formation and survival in the braconid parasitoid wasp Cotesia glomerata (L.) (Hymenoptera: Braconidae) are investigated under various humidity conditions (50, 75, 90, 95 and 100% RH) at 20 °C and under an LD 16 : 8 h photoperiod. The mortality rate at the time of egression from hosts under 100% RH is significantly higher than for other RHs. Cocoon clusters formed at 100% RH spread significantly more than those formed at 50, 75, or 90% RH. Developmental periods differ significantly among RHs under which wasps developed. The mean period from the egression from hosts to adult emergence is 8.7 days when developed at 50–95% RHs, and 8.0 days at 100% RH. The emergence rates of C. glomerata that are maintained under the same humidity conditions after egression from hosts are not significantly different among RHs. However, emergence rates from cocoons that are transferred from 100% RH to 50 and 75% RH are < 70%, although the rates are > 90% in most cases. Some wasps do not emerge from cocoons: more than 60% die after adult eclosion at all RHs; the relative frequency of adult deaths is approximately 90% at 50% RH. Relative humidity influences the cluster and cocoon status strongly: both good clusters and cocoons are formed at low RHs. Emergence rates from cocoons of different ranks are significantly different: the rates of low‐rank cocoons are low at low RHs. The survival of C. glomerata is affected strongly by RH through cocoon formation. 相似文献
Zajonc showed that the attitude towards stimuli that one had been previously exposed to is more positive than towards novel stimuli. This mere exposure effect (MEE) has been tested extensively using various visual stimuli. Research on the MEE is sparse, however, for other sensory modalities.
Methodology/Principal Findings
We used objects of two material categories (stone and wood) and two complexity levels (simple and complex) to test the influence of exposure frequency (F0 = novel stimuli, F2 = stimuli exposed twice, F10 = stimuli exposed ten times) under two sensory modalities (haptics only and haptics & vision). Effects of exposure frequency were found for high complex stimuli with significantly increasing liking from F0 to F2 and F10, but only for the stone category. Analysis of “Need for Touch” data showed the MEE in participants with high need for touch, which suggests different sensitivity or saturation levels of MEE.
Conclusions/Significance
This different sensitivity or saturation levels might also reflect the effects of expertise on the haptic evaluation of objects. It seems that haptic and cross-modal MEEs are influenced by factors similar to those in the visual domain indicating a common cognitive basis. 相似文献
The Medaka is an excellent genetic system for studies of vertebrate development and disease and environmental and evolutionary biology studies. To facilitate the mapping of markers or the cloning of affected genes in Medaka mutants identified by forward-genetic screens, we have established a panel of whole-genome radiation hybrids (RHs) and RH maps for three Medaka chromosomes. RH mapping is useful, since markers to be mapped need not be polymorphic and one can establish the order of markers that are difficult to resolve by genetic mapping owing to low genetic recombination rates. RHs were generated by fusing the irradiated donor, OLF-136 Medaka cell line, with the host B78 mouse melanoma cells. Of 290 initial RH clones, we selected 93 on the basis of high retention of fragments of the Medaka genome to establish a panel that allows genotyping in the 96-well format. RH maps for linkage groups 12, 17, and 22 were generated using 159 markers. The average retention for the three chromosomes was 19% and the average break point frequency was approximately 33 kb/cR. We estimate the potential resolution of the RH panel to be approximately 186 kb, which is high enough for integrating RH data with bacterial artificial chromosome clones. Thus, this first RH panel will be a useful tool for mapping mutated genes in Medaka. 相似文献
Structural studies carried out on the isolated free lipid A of Rhodospirillum tenue 2761 revealed a new type of structure for this lipid. The lipid A backbone of 1',6-linked glucosamine disaccharide (central disaccharide) is substituted by three different sugar residues: the non-reducing end of the disaccharide by 4-amino-4-deoxy-L-arabinose 1-phosphate and its reducing end glycosidically by D-arabinofuranose 1-phosphate; further, the reducing glucosamine of the disaccharide is branched to a third glucosamine residue by a 1',4-glycosidic linkage. The amino and the hydroxyl groups of the central disaccharide are acylated by 3-hydroxydecanoic acid (amide-linked) and palmitic and myristic acids (ester-linked). Neither amino nor hydroxyl groups of the three external sugar residues are acylated. The results suggest the following chemical structure for the lipid A of R. tenue 2761: (formula: see text). 相似文献
Surface of corn starch films was modified through esterification using dodecenyl succinic anhydride (DDSA) as reactant. The effects of reaction temperature and time, concentration of alkaline aqueous solution for activating starch, concentration of ethanol diluted DDSA, and time of alkaline aqueous solution treatment on the physical properties related to material’s hydrophilic nature, such as moisture absorption and surface water contact angle, were investigated. It was found that the surface esterification modification significantly reduced the moisture sensitivity and surface hydrophilic character of starch film. Due to the hydroxyl groups in the film surface layer were reacted with DDSA, the equilibrium moisture content of the starch film under 95% RH declined 22% and the surface water contact angle increased up to 82% after surface esterification modification. 相似文献
The effect of five constant relative humidity (RH) regimes (12%, 33%, 55%, 75% and 94%) on the preimaginal development and adult longevity and reproduction of Dichochrysa prasina Burmeister was studied at 26 ± 1 °C and a photoperiod of 16:8 (L:D) under laboratory conditions. For the experiments, larvae were fed individually on eggs of the flour moth Ephestia kuehniella (Zeller), whereas adults on a liquid diet consisting of water, yeast hydrolysate, sugar and honey. The experimental insects were maintained individually in sealed plastic containers with saturated water salt solutions at the base to control RH. Preimaginal developmental time from egg to adult for females and males was significantly shorter at 75% and 94% RHs than at other RHs in the range from 12% to 55%. Percentages of adult emergence were similar at all RHs tested and varied from 52.5% to 75.0%. Adult females that had no access to water and were maintained at 12%–75% RH lived on average less than two weeks and laid no eggs, whereas at 94% RH they lived longer and each laid on average 201 eggs. When the females had periodic access to a water source a significant increase in both longevity and egg production occurred and the estimated intrinsic rate of increase was high, irrespective of RH. These results could be useful for the mass-rearing of D. prasina and for better understanding its population dynamics under field conditions. 相似文献
Petunia hybrida and Cucurbita pepo pollen was exposed to 30 and 75% relative humidity (RH). Water content, viability and carbohydrate content (glucose, fructose, sucrose and starch) were measured at fixed intervals over 6 h. Water content of C. pepo pollen decreased drastically at both RHs, while P. hybrida pollen dehydrated slightly at RH 30% and hydrated at RH 75%. The pollen of the two species also showed very different sensitivity to dehydration. P. hybrida pollen was resistant to desiccation, with viability remaining around 80% throughout the experiment, whereas C. pepo was very sensitive to desiccation, showing an abrupt decrease in viability when its water content reached about 13% (fresh weight basis) at both RHs. Carbohydrate content was also different in the two species. Sucrose content increased soon after dehydration of P. hybrida pollen at RH 30%, whereas it remained almost constant in C. pepo pollen at the same RH. The results are discussed in the framework of basic pollen physiology and of plant reproductive strategy. 相似文献
Bile acids in the family of steroid compounds can be chemically modified for biochemical and other applications. Derivatives of cholic acid with multiple methacrylate groups can be prepared by the use of methacrylic acid, methacryloyl chloride and methacryloyl anhydride as the acylating agents. The hydroxyl groups of cholic acid methyl ester and cholic acid ethylene glycol ester have been selectively acylated by changing the acylating agents and the number of substitutions have been varied by changing the amount of the acylating agents used. In the acylation reactions with methacryloyl chloride, the reactivity of secondary hydroxyl groups on the steroid skeleton of cholic acid derivatives follows the order of C3>C12>C7. 相似文献
Mass extinction events (MEEs), defined as significant losses of species diversity in significantly short time periods, have attracted the attention of biologists because of their link to major environmental change. MEEs have traditionally been studied through the fossil record, but the development of birth‐death models has made it possible to detect their signature based on extant‐taxa phylogenies. Most birth‐death models consider MEEs as instantaneous events where a high proportion of species are simultaneously removed from the tree (“single pulse” approach), in contrast to the paleontological record, where MEEs have a time duration. Here, we explore the power of a Bayesian Birth‐Death Skyline (BDSKY) model to detect the signature of MEEs through changes in extinction rates under a “time‐slice” approach. In this approach, MEEs are time intervals where the extinction rate is greater than the speciation rate. Results showed BDSKY can detect and locate MEEs but that precision and accuracy depend on the phylogeny's size and MEE intensity. Comparisons of BDSKY with the single‐pulse Bayesian model, CoMET, showed a similar frequency of Type II error and neither model exhibited Type I error. However, while CoMET performed better in detecting and locating MEEs for smaller phylogenies, BDSKY showed higher accuracy in estimating extinction and speciation rates. 相似文献
Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ability of a physician to accurately identify and characterize the middle ear for signs of fluid and/or infection is crucial to provide the most appropriate treatment for the patient. Currently, middle ear infections are assessed with otoscopy, which provides limited and only qualitative diagnostic information. In this study, we propose a method utilizing cross‐sectional depth‐resolved optical coherence tomography to noninvasively measure the diffusion coefficient and viscosity of colloid suspensions, such as a MEE. Experimental validation of the proposed technique on simulated MEE phantoms with varying viscosity and particulate characteristics is presented, along with some preliminary results from in vivo and ex vivo samples of human MEEs.
In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time‐lapse M‐mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes–Einstein diffusion coefficient of the effusion. 相似文献
The successful invasion of Plasmodium is an essential step in their life cycle. The parasite reticulocyte‐binding protein homologues (RHs) and erythrocyte‐binding like proteins are two families involved in the invasion leading to merozoite‐red blood cell (RBC) junction formation. Ca2+ signaling has been shown to play a critical role in the invasion. RHs have been linked to Ca2+ signaling, which triggers the erythrocyte‐binding like proteins release ahead of junction formation, consistent with RHs performing an initial sensing function in identifying suitable RBCs. RH5, the only essential RHs, is a highly promising vaccine candidate. RH5‐basigin interaction is essential for merozoite invasion and also important in determining host tropism. Here, we show that RH5 has a distinct function from the other RHs. We show that RH5‐Basigin interaction on its own triggers a Ca2+ signal in the RBC resulting in changes in RBC cytoskeletal proteins phosphorylation and overall alterations in RBC cytoskeleton architecture. Antibodies targeting RH5 that block the signal prevent invasion before junction formation consistent with the Ca2+ signal in the RBC leading to rearrangement of the cytoskeleton required for invasion. This work provides the first time a functional context for the essential role of RH5 and will now open up new avenues to target merozoite invasion. 相似文献
Abstract The preference for relative humidity (RH) and suitability of different levels of this environmental parameter were investigated in the haematophagous bug Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae). The hygropreference of T. brasiliensis was studied using a RH gradient and the effect of different RHs on the egg hatching, nymph mortality and moulting success was also analysed. The results show that egg hatching in first-instar nymphs of T. brasiliensis was lower at extreme RHs and, particularly, it was lowest at 9.3% RH. The survival of starved nymphs was not affected by RH, but the percentage of engorged nymphs and the ecdysis success of these nymphs once fed was diminished strongly by high humidity. Fourth-instar nymphs preferred to stay at the lowest RH during the first 5 days after feeding and during ecdysis. This preference changed markedly during starvation. Fifteen days after ecdysis, the bugs moved towards intermediate humidities, and 30 days after ecdysis they even preferred the most humid sectors of the gradient. Females preferred to lay eggs in dry environments, suggesting that they may not have a particular hygropreference for oviposition, but that they simply lay their eggs at the RHs where they prefer to stay. 相似文献
Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and microbe interactions. RHs show a fast apical growth, constituting a unique single cell model system for analysing cellular morphodynamics. In this context, live cell imaging using microfluidics recently developed to analyze root development is appealing, although high-resolution imaging is still lacking to enable an investigation of the accurate spatiotemporal morphodynamics of organelles. Here, we provide a powerful coverslip based microfluidic device (CMD) that enables us to capture high resolution confocal imaging of Arabidopsis RH development with real-time monitoring of nuclear movement and shape changes. To validate the setup, we confirmed the typical RH growth rates and the mean nuclear positioning previously reported with classical methods. Moreover, to illustrate the possibilities offered by the CMD, we have compared the real-time variations in the circularity, area and aspect ratio of nuclei moving in growing and mature RHs. Interestingly, we observed higher aspect ratios in the nuclei of mature RHs, correlating with higher speeds of nuclear migration. This observation opens the way for further investigations of the effect of mechanical constraints on nuclear shape changes during RH growth and nuclear migration and its role in RH and plant development. 相似文献
The influence of relative humidity (RH) and temperature on growth and metabolism of eight microfungi on 21 different types of building material was investigated. The fungi were applied as a dry mixture to the materials, which were incubated at 5°C, 10°C, 20°C and 25°C at three humidity levels in the range 69–95% RH over 4–7 months. The lower limit for fungal growth on wood, wood composites and starch-containing materials was 78% RH at 20–25°C and increased to 90% RH at 5°C. An RH of 86% was necessary for growth on gypsum board. Ceramic materials supported growth at RH >90%, although 95% RH was needed to yield chemically detectable quantities of biomass. Almost exclusively only Penicillium, Aspergillus and Eurotium (contaminant) species grew on the materials. Production of secondary metabolites and mycotoxins decreased with humidity and the quantities of metabolites were insignificant compared with those produced at high RH (RH >95%), except in the case of Eurotium.相似文献
Bacteria persist within biofilms on the middle ear mucosa of children with recurrent and chronic otitis media however the mechanisms by which these develop remain to be elucidated. Biopsies can be difficult to obtain from children and their small size limits analysis.
Methods
In this study we aimed to investigate biofilm presence in middle ear effusion (MEE) from children with recurrent acute otitis media (rAOM) and to determine if these may represent infectious reservoirs similarly to those on the mucosa. We examined this through culture, viability staining and fluorescent in situ hybridisation (FISH) to determine bacterial species present. Most MEEs had live bacteria present using viability staining (32/36) and all effusions had bacteria present using the universal FISH probe (26/26). Of these, 70% contained 2 or more otopathogenic species. Extensive DNA stranding was also present. This DNA was largely host derived, representing neutrophil extracellular traps (NETs) within which live bacteria in biofilm formations were present. When treated with the recombinant human deoxyribonuclease 1, Dornase alfa, these strands were observed to fragment.
Conclusions
Bacterial biofilms, composed of multiple live otopathogenic species can be demonstrated in the MEEs of children with rAOM and that these contain extensive DNA stranding from NETs. The NETs contribute to the viscosity of the effusion, potentially contributing to its failure to clear as well as biofilm development. Our data indicates that Dornase alfa can fragment these strands and may play a role in future chronic OM treatment. 相似文献
Optical third harmonic generation (THG) has been observed for the first time from DNA films. The THG signal is observed from NaDNA films exposed to relative humidities (RHs) between 0% and 98%. A strong enhancement (approximately 5x) of the THG signal from NaDNA is observed at 84% RH; no enhancement is observed for RbDNA. The most likely mechanism for such an enhancement is an increased coherence length. A model calculation using estimates of the refractive indices at both the fundamental and third harmonic frequencies supports this interpretation. The observed THG signal has the same polarization as the incident (fundamental) light. For the A conformation, the THG signal polarized perpendicular to the helical axis is approximately twice as strong as the signal polarized parallel to the helical axis. No such anisotropy is observed for either the disordered conformation (below about 50% RH) or the B conformation (above 92% RH). 相似文献
Studies on biology of Oligonychus mangiferus (Rahman and Sapra) at combination of eight constant temperatures and relative humidities (RHs) viz., 7.0°C with 85% RH, 10°C with 80% RH, 15.0°C with 75% RH, 23.0°C with 70% RH, 31.0°C with 65% RH, 34.0°C with 65% RH, 36.0°C with 60% RH and 40.0°C with 55% RH revealed that the optimal condition for the development of these mites are 15.0–31.0°C and 65–75% RH. The highest temperature and the lowest RH accelerated the rate of development and induced more reproduction of O. mangiferus. Its population also multiplied 30.81 times in a generation time of 27.36 days at 31.0°C and 65% RH, while the same population only increased 7.46 times in a generation time of 48.07 days at 15.0°C and 75% RH. Fecundity was highest at 31.0°C and 65% RH with 46.43 eggs per female. The highest intrinsic rate of natural increase was observed at 31.0°C as 0.125 per day. 相似文献
In the present paper laser desorption mass spectrometry (LDMS) was applied to dephosphorylated free lipid A preparations obtained from lipopolysaccharides of Re mutants of Salmonella minnesota, Escherichia coli and Proteus mirabilis. The purpose of this study was to elucidate the location of (R)-3-hydroxytetradecanoic acid and 3-O-acylated (R)-3-hydroxytetradecanoic acid residues which are bound to amino and hydroxyl groups of the glucosamine disaccharide backbone of lipid A. Based on the previous finding from biochemical analyses that the amino group of the nonreducing glucosamine residue (GlcN II) of the backbone carries, in S. minnesota and E. coli, 3-dodecanoyloxytetradecanoic acid and, in P. mirabilis, 3-tetradecanoyloxytetradecanoic acid, a self-consistent interpretation of the LDMS was possible. It was found that: (a) in all three lipids A GlcN II is, besides the amide-linked 3-acyloxyacyl residue, substituted by ester-linked 3-tetradecanoyloxytetradecanoic acid; (b) the reducing glucosamine (GlcN I) is substituted by ester-linked 3-hydroxytetradecanoic acid; (c) the amino group of GlcN I carries a 3-hydroxytetradecanoic acid which is non-acylated in E. coli and which is partially acylated by hexadecanoic acid in S. minnesota and P. mirabilis. In lipids A which were obtained from the P. mirabilis Re mutant grown at low temperature (12 degrees C) LDMS analysis revealed that specifically the one fatty acid bound to the 3-hydroxyl group of amide-linked 3-hydroxytetra-decanoic acid at GlcN II is positionally replaced by delta 9-hexadecenoic acid (palmitoleic acid). It appears, therefore, that enterobacterial lipids A resemble each other in that the 3-hydroxyl groups of the two 3-hydroxytetradecanoic acid residues linked to GlcN II are fully acylated, while those of the two 3-hydroxytetradecanoic acid groups attached to GlcN I are free or only partially substituted. 相似文献