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1.
An entomopoxvirus infecting fat body cells of Anacridium aegyptium is reported. Spheroid virus occlusion bodies, ranging in size from 3 to 8 μm, contain virions 336–356 nm long and 210–217 nm wide. The virion ultrastructure indicates that the newly discovered virus belongs to the genus Entomopoxvirus B known to infect Lepidoptera and Orthoptera.  相似文献   

2.
The cell of Pyrocystis spp. is covered by an outer layer of material resistant to strong acids and bases. Internal to this layer much of the cell wall is composed of cellulose fibrils. The presence of cellulose fibrils was established by staining raw and ultra-violet–peroxide-cleaned cell walls and by combining X-ray diffraction spectroscopy with electron microscope observation. Carbon replicas of freeze-etched preparations and thin sections of P. lunula walls show outer layers, inside them ca. 24 layers of crossed parallel cellulose fibrils (4–5 nm thick, ca. 12 nm wide), then a region of smaller (ca. 6–12 nm diameter) fibrils in a disperse texture, and then the plasma membrane. Cellulose fibrils in the parallel texture are constructed of 3–5 elementary fibrils ca. 3 nm in diameter. Walls of P. fusiformis and P. pseudonctiluca also have cellulose fibrils in a crossed parallel texture similar to those of P. lunula. The Gymnodinium-type swarmer from lunate P. lunula appears to have a cell wall ultrastructure typical of other “naked” dinoflagellates.  相似文献   

3.
Envelopes of the mineralizing protist, Trachelomonas hispida var. coronata Lemm., were examined by light and electron microscopy and by electron diffraction analysis. The ellipsoidal hollow envelope is made of mineralized strands of mucilage (muci-strands) that form a compact wall 0.2–4.0 μm thick, interspersed with numerous puncta 0.2–0.3 μm in diameter and, in some instances with tapered spines ca. 0.6 μm long and 0.7 μm wide at the base. The mucilage strands are cylindrical, anastomosing threads 20 nm thick. Electron-dense, needle-shaped mineral deposits form axial cores in the strands. Also, powdery granular mineral deposits are dispersed sparingly throughout the mucilage matrix. Micromicro-electron diffraction analyses verify the crystalline nature of the needle-shaped deposits, which are 4–9 nm thick and vary in length (20–100 nm). The mucilage strands and microcrystallites pervade the whole of the envelope matrix, including the spines, and may be preferentially oriented along the envelope surfaces.  相似文献   

4.
Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae) are destructive weevils on Ailanthus altissima in China. This study examined phototactic behaviour of E. scrobiculatus and E. brandti in response to eight light-emitting diodes (LEDs) in the laboratory and field. Effects of gender, starvation, and light and dark experience on the phototactic behaviour of the insects were evaluated. The results demonstrated that, the two species of weevil were phototactic insects and most sensitive to violet light (400–405?nm), followed by blue–violet light (420–430?nm). They were less sensitive to red (655–660?nm), white (6000–6500?k), blue–green (470–480?nm), yellow (590–595?nm), blue (450–455?nm), and green (515–530?nm) light. In the light intensity range of 200–1000?lux, the light intensity had no significant effect on the phototatic behaviour of E. scrobiculatus and E. brandti. Phototactic behaviour of the insects was affected by gender. The phototaxis indices of the two species of weevil increased with starvation, reaching a plateau after 2 or 3?d of starvation. The phototaxis indices of E. scrobiculatus and E. brandti were significantly affected by various wavelengths of light following exposure to the light for 3?h or in different dark experience time. In the mark-release-recapture test, the number of E. scrobiculatus and E. brandti adults trapped by violet (400–405?nm) light traps is the largest. The information provided here provides a basis for survey and control of E. scrobiculatus and E. brandti.  相似文献   

5.
A virus causing ringspot of Passiflora edulis in the Ivory Coast   总被引:1,自引:0,他引:1  
A mechanically transmissible virus causing leaf mottling and ringspotting of Passiflora edulis var. flavicarpa in the Ivory Coast is described. Its particles are flexuous rods 810–830 nm long and 15 nm wide. It infects mainly species of Passifloraceae and Leguminosae; Passiflora foetida is a good diagnostic host. Aphis gossypii and Aphis spiraecola transmit the virus after brief acquisition feeds. Seed transmission was not detected. In crude sap of P. edulis, infectivity was lost after 10 min at 65–70 °C, 12–14 days at 24 °C or dilution to 10-7. A purification method is described, using Triton-X-100 as clarifying agent. The virus is serologically related but not identical to passionfruit woodiness virus from Queensland. The virus seems to belong to the potato virus Y group and has the cryptogram */*:*/(6):E/E:S/Ap. It is designated passionfruit ringspot virus.  相似文献   

6.
Hess, R. T., Poinar, Jr., G. O., Etzel, L., Merritt, C. C. 1980. Calyx particle morphology of Bathyplectes anurus and B. curculionis (Hymenoptera: Ichneumonidae). (Department of Entomological Sciences, University of California, Barkeley, California, U.S.A.) — Acta zool. (Stockh.) 61(2): 111–116. The calyx regions of the ichneumonid wasps Bathyplectes anurus and B. curculionis were observed with the electron microscope to contain ovoid membrane-bound particles, 300 nm long by 250 nm wide. These particles were produced in nuclei associated with fibrous strands from which they appeared to bud. Particles apparently moved into the cytoplasm and budded into the calyx lumen, thereby acquiring the host's plasma membrane. The similarities and differences of these particles to the calyx particles of other wasps is discussed.  相似文献   

7.
Summary— The quick-freezing and freeze-etching technique was used to analyse the cytoskeleton of Tritrichomonas foetus, a pathogenic protozoan of the urogenital tract of cattle. The cytoplasm presented a network of filamentous structures interacting with each other, with the surface of the hydrogenosomes and the nuclear membrane. Two nm wide filamentous structures were found in the luminal space of the Golgi complex, connecting the two faces of each cisterna. The microtubules of the pelta-axostyle system were connected by bridges 30–40 nm long and 10 nm wide, regularly spaced with an interval of 25 nm. The costa is a structure formed by a complex array of filaments and globous structures. It seems to be connected to the recurrent flagellum through a complex network formed by 15 and 10 nm wide filaments which emerge from the peripheral region of the costa and penetrate into the surface projections of the protozoan body to which the recurrent flagellum is attached. Other filaments were seen connecting the surface of these projections with the surface of the flagellum.  相似文献   

8.
The new series Elatostema section Elatostema series Albopilosoides Q.Lin & L.D.Duan (Urticaceae) is described, and two new species of Elatostema, namely Elatostema albopilosoides Q.Lin & L.D.Duan and Elatostema purpureum Q.Lin & L.D.Duan. from south Guizhou province, south‐west China are described and illustrated. Both species were found growing only at the base of a large limestone chamber at an altitude of c. 800 m. Elatostema albopilosoides is morphologically similar to E. albopilosum W.T.Wang, but differs by having female inflorescences with peduncles 10–60 mm long (0–1.5 mm long in E. albopilosum) and receptacles 7–27 mm long, 7–24 mm wide (E. albopilosum: 1–4 mm long and 1–3 mm wide). Elatostema purpureum is also morphologically similar to E. albopilosum, but has stipules 5–6 mm long, 0.8–1.5 mm wide (4–7 mm long, 1.5–2.8 mm wide in E. albopilosum) and leaf blades obliquely elliptical to obliquely oblong‐obovate, 3.5–7.5 mm long and 1.5–2.5 mm wide (obliquely narrowly oblanceolate‐oblong, 12–17 cm long, 3–5 cm wide in E. purpureum:). © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 674–680.  相似文献   

9.
The reversing-pulse electric birefringence (RPEB) technique was applied to the study of the temperature effect on the electrooptical and hydrodynamic properties of a fractionated [Glu(OBzl)]n sample, which is molecularly dissolved in cyclohexanone. The aim was to develop a standard analytical method for thermal denaturation and temperature-induced conformational transitions. The field-on reverse and steady-state signal, and the field-off decay signal, were measured at 535 nm and at a constant low field strength (ca. 3 kV/cm) over a wide temperature range (5–90°C). The steady-state birefringence and the relaxation time in the decay process were also measured at two constant temperatures (5 and 70°C) over a wide field strength range (E ≤ 20 kV/cm). By the combination of these two different sets of RPEB measurements, the unwanted effect of the high pulse field on polymer conformation at elevated temperatures could be minimized. Together with the density and viscosity of cyclohexanone measured between 5 and 95°C, the following quantities could be evaluated: the weight-average permanent dipole moment and polarizability anisotropy, the reduced optical anisotropy factor (Δg/n), the weight-average length, and the degree of polydispersity. All these quantities, except for Δg/n, were found to be almost independent of temperature (5–90°C) and concentration (1.54–4.27 mM).  相似文献   

10.
Three new benthic, sand-dwelling dinqflagellate species, Prorocentrum sabulosum, Prorocentrum scuptile, and Prorocentrum arenarium, from coral rubble are described from scanning electron micrographs. Species were identified based on shape, size, surface micromorphology, ornamentation of thecal plates, and architecture of the periflagellar area and intercalary band. Cells of P. sabulosum are oval with a cell size of 48–50 μm long and 41–48 μm wide. The areolae are round to oval and numerous (332–450 per valve) and range from 1 to 1.6 μm in size. The periflagellar area of P. sabulosum bears a wide V-shaped depression with a flat ridge and lacks ornamentation; it accommodates six pores: one large flagellar pore, an adjacent smaller auxiliary pore, and four pores of unknown function. The flagellar and auxiliary pores are surrounded by a narrow apical collar. The intercalary band of P. sabulosum is smooth. Prorocentrum sculptile cells are broadly oval, 32–37 nm long, and 30–32 μm wide in valve view with a deep-sculptured apical area. The valves are smooth and are marked with shallow depressions (856–975 per valve). Some of these depressions have a small round opening (0.13 μm in diameter). The periflagellar area is V-shaped with a deeply indented depression; it accommodates the two flagella and a thin angled apical plate. The intercalary band is smooth. Prorocentrum arenarium cells are nearly round in valve view 30–32 μm in diameter. Thecal surface is smooth with scattered kidney-shaped valve poroids (65–73 per valve) and marginal poroids (50–57 per valve). Length and width of poroids are 0.62 μm and 0.36 μm, respectively. The periflagellar area is an unornamented, broad triangle into which a large flagellar pore and a smaller auxiliary pore are fitted. Both flagella, longitudinal and transverse, protrude from the flagellar pore. The intercalary band is smooth. The presence of a peduncle-like structure (2–3 μm long) in P. arenarium was observed situated in the flagellar pore.  相似文献   

11.
Sawada T. and Inoue S. 2011. Ultrastructure of irregular collagen fibrils of shark mandible. —Acta Zoologica (Stockholm) 92 : 62–66. Collagen fibrillogenesis was investigated in developing fibrous connective tissue (tooth band) in shark mandible by transmission electron microscopy. Fibrils varied considerably in shape and size. Both thin and thick fibrils 40–200 and 400–500 nm in width, respectively, were observed, with the latter showing irregular contours. Examination of both transverse and longitudinal sections of fibril suggested that the irregular, thick fibrils were formed by fusion of the thin fibrils. This was in agreement with a previously proposed mechanism of collagen fibrillogenesis in a variety of tissues, in which formation of thin fibrils is followed by their coalescence into thicker fibrils. Detailed high resolution ultrastructural examination revealed decorin‐like, 4.5‐ to 5.5‐nm‐wide polygonal frames and 3‐nm‐wide ribbon‐like structures previously identified as chondroitin sulfate proteoglycan ‘double tracks’ localized within the interfibrillar spaces. These structures may be closely involved in collagen fibrillogenesis.  相似文献   

12.
The bacteria Bacillus thuringiensis mutant is highly producing melanin pigment with increased ultra violet resistance and insecticidal activity against the potato tuber moth Phthorimaea operculella (Zeller). The results showed that the high decrease of crystal protein formation rate ranged from 100% (B.t.EMS-M2 and B.t.EMS-M6) to 91.82% (B.t.EMS-M9). The EMS–UV-induced mutants (B.t.EMS–UV-2h-1, B.t. EMS–UV-2h-2, B.t.EMS–UV-2h-3, B.t.EMS–UV-2h-5, B.t.EMS–UV-4h-1, B.t.EMS–UV-4h-3 and B.t.EMS–UV-6h-2) showed 100% decrease in the crystal protein formation. Results also showed that the growth rate of B. thuringiensis isolates was detected by measuring the light absorption of culture broth (BP media at pH 8) at the wavelength of 600 nm. The absorbance values of the standard melanin were 2.055 and 0.134 at wavelengths of 226.5 and 602 nm, respectively. This means that the maximum absorbance at wavelength was 226.5 nm, this result is similar to that of the synthetic melanin which has the absorbance of 226 nm. Our experiments detected that the pigment extracted from the mutant isolate B.t.EMS-M3 (EMS-induced mutant) gave the maximum value of absorbance (2.615) at wavelength of 227.5 nm that was similar to standard melanin which gave absorbance value about 2.055 at a wavelength of 226.5 nm. This may be due to the genetic alterations that happened to the mutant isolates due to the mutation by EMS or/and UV irradiation.  相似文献   

13.
An investigation of a virulent Bacillus phage-K2 (named Bp-K2) isolated from chungkookjang (a fermented soybean foodstuff) was made. Bp-K2 differed in infectivity against a number of Bacillus subtilis strains including starter strains of chungkookjang and natto, being more infectious to Bacillus strains isolated from the chungkookjang, but much less active against a natto strain. Bp-K2 is a small DNA phage whose genome size is about 21 kb. Bp-K2 is a tailed bacteriophage with an isometric icosahedral head (50 nm long on the lateral side, 80 nm wide), a long contractile sheath (85–90 nm × 28 nm), a thin tail fiber (80–85 nm long, 10 nm wide), and a basal plate (29 nm long, 47 nm wide) with a number of spikes, but no collar. The details of the structures of Bp-K2 differ from natto phage ϕBN100 as well as other known Bacillus phages such as SPO1-like or ϕ 29-like viruses. These data suggest that Bp-K2 would be a new member of the Myoviridae family of Bacillus bacteriophages.  相似文献   

14.
Hard carbons (HCs) are promising anodes of sodium‐ion batteries (SIBs) due to their high capacity, abundance, and low cost. However, the sodium storage mechanism of HCs remains unclear with no consensus in the literature. Here, based on the correlation between the microstructure and Na storage behavior of HCs synthesized over a wide pyrolysis temperature range of 600–2500 °C, an extended “adsorption–insertion” sodium storage mechanism is proposed. The microstructure of HCs can be divided into three types with different sodium storage mechanisms. The highly disordered carbon, with d002 (above 0.40 nm) large enough for sodium ions to freely transfer in, has a “pseudo‐adsorption” sodium storage mechanism, contributing to sloping capacity above 0.1 V, together with other conventional “defects” (pores, edges, heteroatoms, etc.). The pseudo‐graphitic carbon (d‐spacing in 0.36–0.40 nm) contributes to the low‐potential (<0.1 V) plateau capacity through “interlayer insertion” mechanism, with a theoretical capacity of 279 mAh g?1 for NaC8 formation. The graphite‐like carbon with d002 below 0.36 nm is inaccessible for sodium ion insertion. The extended “adsorption–insertion” model can accurately explain the dependence of the sodium storage behavior of HCs with different microstructures on the pyrolysis temperature and provides new insight into the design of HC anodes for SIBs.  相似文献   

15.
The wing colors of eight lycaenid species of the genera Favonius and Quercusia were examined with a spectrophotometer. Four (F. orientalis, F. taxila, F. jezoensis and F. ultramarinus) of five green to blue‐green Favonius species had a double‐peaked pattern, reflecting UV light (345–355 nm) and green light (515–525 nm), whereas F. cognatus reflected only visible green light (539 nm). Thus, the species considered most closely related, F. ultramarinus and F. cognatus, had quite different wing colors in terms of insect vision. Two bluish species had utterly different reflection patterns: F. saphrinus had a single peak in the UV range and Q. fujisana had two peaks, one each in the UV and visible light ranges. The black F. yuasai did not have any peak in the examined range of wavelengths (300–700 nm).  相似文献   

16.
《Luminescence》2003,18(3):145-155
The purpose of the present paper was to study the influence of bacteria harbouring the luciferase‐encoding Vibrio harveyi luxAB genes upon the spectral emission during growth in batch‐culture conditions. In vivo bioluminescence spectra were compared from several bioluminescent strains, either naturally luminescent (Vibrio fischeri and Vibrio harveyi) or in recombinant strains (two Gram‐negative Escherichia coli::luxAB strains and a Gram‐positive Bacillus subtilis::luxAB strain). Spectral emission was recorded from 400 nm to 750 nm using a highly sensitive spectrometer initially devoted to Raman scattering. Two peaks were clearly identified, one at 491–500 nm (± 5 nm) and a second peak at 585–595 (± 5 nm) with the Raman CCD. The former peak was the only one detected with traditional spectrometers with a photomultiplier detector commonly used for spectral emission measurement, due to their lack of sensitivity and low resolution in the 550–650 nm window. When spectra were compared between all the studied bacteria, no difference was observed between natural or recombinant cells, between Gram‐positive and Gram‐negative strains, and growth conditions and growth medium were not found to modify the spectrum of light emission. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

17.
We have used atomic force microscopy and scanning tunnelling microscopy to extract new information about the substructure of the Alnus, Betula, Fagus, Lycopodium and Rhododendron pollen grain exine. Our scans of exines using atomic force microscopy and scanning tunnelling microscopy reveal somewhat similar substructures for Lycopodium spores and pollen of Alnus, Betula, Fagus and Rhododendron. They show various levels of alignment and clustering of substructure components. Except for Alnus, which showed polygonal clustering of spheroids and weak alignment, there is pronounced alignment of helical units. In Betula, Fagus, Lycopodium and Rhododendron the subunits appear to be helical or perhaps consisting of elongated spheroids, these spheroids are however arranged in a way that suggest that they are part of a helical structure. The diameter of these helical subunits range from 10–15 nm in Fagus, 20–25 nm in Lycopodium, 35–90 nm in Rhododendron up to 70–120 nm in Betula. Our preparations graded from intact or fractured fresh pollen to pollen that was acetolyzed, chemically fixed and epoxy resin embedded. While our knowledge of the exact radial/lateral orientation of most of our scans is less than perfect there were in all cases substructures or cross connections of exine units. We found results from scanning and transmission electron microscopy to be helpful in understanding images from Atomic Force- and Scanning Tunnelling Microscopy.  相似文献   

18.
A new fluorescent probe, 4‐N,N‐di(2‐hydroxyethyl)imino‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (HINBD) was synthesized in a single step with reasonably good yield. The water‐soluble HINBD emits strongly in the visible region (λex = 479 nm, λem = 545 nm) and is stable over a wide range of pH values. It was found that vitamin B12 (VB12) had the ability to quench the fluorescence of HINBD, and the quenched fluorescence intensity was proportional to the concentration of VB12. A method for VB12 determination based on the quenching fluorescence of HINBD was thus established. Interference effects of various substances, including sugars, vitamins, amino acids, inorganic cations and some organic substances have been studied. Under optimal conditions, the linear range is 0.0–2.4 × 10–5 mol/L. The determination limit is 8.3 × 10–8 mol/L. The method was applied to measure VB12 in pharmaceutical preparations with satisfactory results. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

19.
In this study, we have synthesized phenyl‐substituted triphenylene derivatives, using the Diels–Alder reaction and the Buchwald–Hartwig reaction. To investigate electroluminescence properties of these materials, multilayer organic light‐emitting diode (OLED) devices were fabricated with a structure of indium–tin–oxide (ITO) (180 nm)/4,4′‐bis(N‐(1‐naphthyl)‐N‐phenylamino)biphenyl (NPB) (50 nm)/blue‐emitting materials (1–3) (30 nm)/bathophenanthroline (Bphen) (35 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). A device using N2,N2,N11,N11,5,6,7‐heptaphenyltriphenylene‐2,11‐diamine (2) exhibited efficient blue emission with luminous, power, and external quantum efficiencies of 0.92 cd/A, 0.67 lm/W, and 1.17% at 20 mA/cm2, respectively. The Commission International de L'Éclairage coordinates of this device were (x = 0.15, y = 0.09) at 6.0 V. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

20.
Images of individual exine units from the tectum of Nuphar luteum (L.) Sm. pollen were made using atomic force microscopy. These units were recorded as being 120 to 160 nm wide. Exine-units sectioned transversally were circular and had a central circular (core) zone 40 nm or more in diameter. Exine unit-structures in Nuphar have an outer (binder) substructure coiled around a core zone.  相似文献   

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