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1.
Summary Spectral sensitivity functions S() of single photoreceptor cells in 43 different hymenopteran species were measured intracellularly with the fast spectral scan method. The distribution of maximal sensitivity values (max) shows 3 major peaks at 340 nm, 430 nm and 535 nm and a small peak at 600 nm. Predictions about the colour vision systems of the different hymenopteran species are derived from the spectral sensitivities by application of a receptor model of colour vision and a model of two colour opponent channels. Most of the species have a trichromatic colour vision system. Although the S() functions are quite similar, the predicted colour discriminability curves differ in their relative height of best discriminability in the UV-blue or bluegreen area of the spectrum, indicating that relatively small differences in the S() functions may have considerable effects on colour discriminability. Four of the hymenopteran insects tested contain an additional R-receptor with maximal sensitivity around 600 nm. The R-receptor of the solitary bee Callonychium petuniae is based on a pigment (P596) with a long max, whereas in the sawfly Tenthredo campestris the G-receptor appears to act as filter to a pigment (P570), shifting its max value to a longer wavelength and narrowing its bandwidth. Evolutionary and life history constraints (e.g. phylogenetic relatedness, social or solitary life, general or specialized feeding behaviour) appear to have no effect on the S() functions. The only effect is found in UV receptors, for which max values at longer wavelengths are found in bees flying predominantly within the forest.  相似文献   

2.
To examine the influence of the spectral characteristics of underwater light on spectral sensitivity of the ON and OFF visual pathways, compound action potential recordings were made from retinal ganglion cells of threespine stickleback from different photic regimes. In fish from a red-shifted photic regime (P50 680 nm for downwelling light at 1m), peak sensitivity of both the ON and OFF pathways was limited to long wavelength light (max 600–620). In contrast, the ON pathway of fish from a comparatively blue-shifted (P50 566 nm) photic regime exhibited sensitivity to medium (max 540–560) and long (max 600 nm) wavelengths, while the OFF pathway exhibited peak sensitivity to only medium (max 540 nm) wavelength light. In a third population, where the the ambient light is moderately red-shifted (P50 629 nm), the ON pathway once again exhibited only a long wavelength sensitivity peak at 620 nm, while the OFF pathway exhibited sensitivity to both medium (max 560 nm) and long (max 600–620 nm) wavelength light. These findings suggest that the photic environment plays an integral role in shaping spectral sensitivity of the ON and OFF pathways.  相似文献   

3.
Responses of single visual cells of the anterior part of the compound eye of the oriental cockroachBlatta orientalis were recorded intracellularly. Two spectral types of cells were discovered: ultraviolet receptors with max 361 nm and green-sensitive receptors with max 503 nm. The spectral curve of the whole eye, measured by the electroretinogram, included two peaks (=350–370 and 500 nm) and a minimum between 400 and 430 nm. This last fact is interpreted as additional evidence of the dichromatic vision of the cockroach.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 17, No. 1, pp. 57–61, January–February, 1985.  相似文献   

4.
Summary Scotopic visual pigments measured in the creek chub and the white sucker are porphyropsins with mean max values located at 538.3 and 536.5 nm, respectively. There is a shift of the max towards shorter wavelengths during the winter in both of these species coinciding with similar changes in the quality of downwelling light. max is significantly correlated to the P50 and spectrum width of the downwelling light and dissolved oxygen. An analysis of variance shows that there are significant differences between the max values of: fish in the two lakes, fish at different times, the two species at different times and fish in different lakes at different seasons. The offset visual pigments of both species appear to be well adapted to their photic environment in terms of the contrast hypothesis. This improvement of contrast detection is discussed in relation to their feeding habits.Abbreviations max wavelength at which absorbance is maximum - P50 wavelength which halves the total number of photons between 400 and 700 nm, a measure of spectral quality - PAR photosynthetically active radiation - MSP microspectrophotometric - SE standard error  相似文献   

5.
Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara  相似文献   

6.
Electroretinogram (ERG) flicker photometry was used to study the spectral mechanisms in the retinas of white-tailed deer (Odocoileus virginianus) and fallow deer (Dama dama). In addition to having a rod pigment with maximum sensitivity (max) of about 497 nm, both species appear to have two classes of photopic receptors. They share in common a short-wavelength-sensitive cone mechanism having max in the region of 450–460 nm. Each also has a cone having peak sensitivity in the middle wavelengths, but these differ slightly for the two species. In white-tailed deer the max of this cone is about 537 nm; for the fallow deer the average max value for this mechanism was 542 nm. Deer resemble other ungulates and many other types of mammal in having two classes of cone pigment and, thus, the requisite retinal basis for dichromatic color vision.Abbreviations ERG electroretinogram - LWS long wavelength sensitive - MWS middle wavelength sensitive - SWS short wavelength sensitive  相似文献   

7.
A simple one variable caricature for oscillating and excitable reaction-diffusion systems is introduced. It is shown that as a parameter, , varies the system dynamics change from oscillatory ( > 0) to excitable ( < 0) and the frequency of the oscillation vanishes as for 0. When such dynamics are coupled by continuous diffusion in a ring geometry (1-space dimension), propagating wave trains may be found. On an infinite ring excitable devices lead to unique solitary waves which are analogous to pulse waves. A solvable example is presented, illustrating properties of dispersion, excitability, and waves. Finally it is shown that the caricature arises in a natural way from more general excitable/oscillatory systems.  相似文献   

8.
Summary Growth of and of some lambdoid phages is considerably inhibited on strain 3057 derived from E. coli 15T-. Mutants of which overcome this inhibition map in gene N. Some of these hty mutants are temperature sensitive for growth on E. coli K12. Thus plating of on strain 3057 allows one to isolate temperature sensitive N mutants. The hty mutants produce less than normal N activity as judged by their low efficiency of plating on a nus - host and by the extended latent period of some of them on normal hosts. The inability of strain 3057 to propagate can be at least partially reversed by addition of thymidine to the medium and the growth difference between hty and in 3057 increases with decreasing thymidine concentration. The amount of DNA produced by in 3057 at low thymidine concentration is lower than that produced by hty under the same conditions. Only a small percentage of the DNA produced by in 3057 is packaged into viable phage particles. This suggests that not only produces less DNA in 3057 than hty but that an important part of the DNA in 3057 is in a form which can not be packaged or which is noninfective for other reasons. A hypothesis is discussed that hty mutations enable to grow on E. coli 15T- at low thymidine concentration because they lead to reduction in the number of single strand nicks in the DNA by reducing the intracellular endonuclease activity. Under permissive conditions conditional lethal N mutants are favored for growth on 3057 over N + which confirms the idea that N activity or the activity of a gene under N control interferes with growth in 3057 at low thymidine concentration.  相似文献   

9.
The endophytic cyanobacterium, Anabaena azollae, isolated from laboratory cultures of Azolla caroliniana Willd., contains three spectroscopically distinct biliproteins. About 70% of the biliprotein is c-phycocyanin (max 610 nm) and 13% is allophycocyanin (max 647 nm, shoulder 620 nm). A third pigment corresponds to phycoerythrocyanin (max 570 nm, shoulder 590 nm). In very dilute solutions of allophycocyanin, at constant pH and buffer strength, the 647 nm maximum disappears and a single max occurs at 615–620 nm. The 647 nm absorption maximum reappears upon concentrating the dilute solution. Very dilute solutions of phycoerythrocyanin exhibit a broad peak between 570 and 590 nm. Absorption spectra of c-phycocyanin are not significantly altered upon dilution. Fluorescence emission maxima of phycoerythrocyanin, c-phycocyanin, and allophycocyanin occur at 630 nm, 643 nm and 660 nm respectively, using 540 nm excitation. Two subunits, of molecular weight 16,500 () and 20,600 (), are seen in c-phycocyanin upon dissociation with SDS. Dissociation of allophycocyanin and phycoerythrocyanin with SDS yields one sizeclass of subunits, with a molecular weight of about 17,500 for allophycocyanin and 18,000 for phycoerythrocyanin.Contribution No. 684 Offprint requests to: G. A. Peters  相似文献   

10.
We report on the lens pigmentation and visual pigments of 52 species of demersal deep-sea fishes caught at depths ranging from 480 m to 4110 m in the Porcupine Seabight and Goban Spur area of the North-eastern Atlantic. Only one species, caught between 480 and 840 m, had a lens with large amounts of pigment, consistent with the hypothesis that heavily pigmented lenses in deep-sea fish serve to enhance the contrast of bioluminescent signals by removing much of the background radiance, which is only visible to fish living shallower than 1000 m. Low concentrations of lens pigmentation were also observed in a further two species (Rouleina attrita and Micromesisteus poutassou). The retinae of all species except five, contained only a single visual pigment, as determined by microspectrophotometry of individual rods, and/or spectrophotometry of retinal wholemounts and retinal extracts. Those fishes caught between 500 m and 1100 m had wavelengths of peak sensitivity (max) ranging from 476 nm to 494 nm, while most fish living below 1100 m tended to be more conservative with (max) values ranging from 475 nm to 485 nm. The only exceptions to this were three deep-living species caught between 1600 m and 2000 m whose retinae contain abnormally short-wave sensitive visual pigments (Cataetyx laticepsmax 468 nm; Alepocephalus bairdiimax 467 nm; Narcetes stomias max 472 nm), suggesting adaptation for the detection of short-wave bioluminescence.  相似文献   

11.
The fluorescence behavior of two tryptophans (Trp-134, Trp-213) in bovine serum albumin (BSA) and a single tryptophan (Trp-214) in human serum albumin (HSA) was examined. The maximum emission wavelength (max) was 340.0 nm for both proteins. In a solution of sodium dodecyl sulfate (SDS), the max of BSA abruptly shifted to 332 nm at 1 mM SDS and then reversed to 334 nm at 3 mM SDS. The max of HSA gradually shifted to 330 nm below 3 mM SDS, although it returned to 338 nm at 10 mM SDS. In contrast to this, in a solution of dodecyltrimethylammonium bromide, the max positions of BSA and HSA gradually shifted to 334.0 and 331.5 nm, respectively. Differences in the fluorescence behavior of the proteins are attributed to the fact that Trp-134 exists only in BSA, with the assumption that Trp-213 of BSA behaves the same as Trp-214 of HSA. The Trp-134 behavior appears to relate to the disruption of the helical structure in the SDS solution.  相似文献   

12.
Summary Increment threshold measurements in wild rabbits give rise to spectral sensitivity curves that are unimodal or bimodal in nature, depending on the background luminance. We propose a model that explains the shape of these curves on the basis of synergistic and antagonistic interaction of blue cones (max = 425 nm), green cones (max = 523 nm) and rods (max = 498 nm).  相似文献   

13.
D. C. Morgan  R. Child  H. Smith 《Planta》1981,151(5):497-498
In background white light, supplementary far-red (max 700 nm) is an order of magnitude less effective than supplementary far-red (max 739 nm) in the stimulation of stem extension in Sinapis alba. The relationship between phytochrome photoequilibrium and extension rate increase for the two supplementary far-red treatments is, however, very similar. This evidence indicates that phytochrome cycling is not involved in the phytochrome control of stem extension in light-grown Sinapis alba and that the response to supplementary far-red light is not fluence rate (irradiance) dependent.Abbreviations Pfr far-red absorbing form of phytochrome - the phytochrome photoequilibrium (Pfr/Ptotal)  相似文献   

14.
Reef-building corals from shallow waters are known to contain a suite of water soluble compounds (collectively named S-320) which strongly absorb near-UV light. Compounds of this type have now been isolated from the Pacific staghor coral Acropora formosa and identified as a series of mycosporine-like amino acids including mycosporine-Gly (max=310nm), palythine (max=320nm) and palythinol (max=332nm). These compounds were separated and quantified by high-performance liquid chromatography. Serial extraction efficiencies were calculated using a simple formula which is derived herein. For 12-cm long coral branches collected from a depth of 3 m at Rib Reef, Great Barrier Reef, Australia (146° 53E, 18° 29S) the average concentrations of mycosporine-Gly, palythine, and palythinol were 37.8, 56.4 and 0.895 nmol per mg coral protein, respectively. The coral samples can be stored at-20°C for at least 144 days without degradation of the mycosporinelike amino acids.Contribution number 334 from the Australian Institute of Marine Science  相似文献   

15.
The visual pigments and photoreceptor types in the retinas of three species of Pacific salmon (coho, chum, and chinook) were examined using microspectrophotometry and histological sections for light microscopy. All three species had four cone visual pigments with maximum absorbance in the UV (max: 357–382 nm), blue (max: 431–446 nm), green (max: 490–553 nm) and red (max: 548–607 nm) parts of the spectrum, and a rod visual pigment with max: 504–531 nm. The youngest fish (yolk-sac alevins) did not have blue visual pigment, but only UV pigment in the single cones. Older juveniles (smolts) had predominantly single cones with blue visual pigment. Coho and chinook smolts (>1 year old) switched from a vitamin A1- to a vitamin A2-dominated retina during the spring, while the retina of chum smolts and that of the younger alevin-to-parr coho did not. Adult spawners caught during the Fall had vitamin A2-dominated retinas. The central retina of all species had three types of double cones (large, medium and small). The small double cones were situated toward the ventral retina and had lower red visual pigment max than that of medium and large double cones, which were found more dorsally. Temperature affected visual pigment max during smoltification.  相似文献   

16.
Summary A selection technique, using the thermoinducible prophage CI857Nsus7 Nsus53, has lead to the characterization of a new class of prophage mutations (called r), which prevent host killing upon thermal induction.N-defective r mutants efficiently complement i434 or O and P mutants, but not the corresponding mutants of i21. Complementation data suggest that the i21 hybrid fails to provide the positive regulatory mechanism dependent on the N-gene product, since it cannot activate the Q gene of a N-defective mutant. Thus, it seems possible that r mutants cannot express genes O and P unless the N-gene product is present in the cell. This interpretation is supported by the fact that r mutants are not defective and form plaques when their N-gene is functional. r mutation confer a clear phenotype, and map in the y-CII region. Results of a density gradient analysis suggest that they result from small insertions of DNA. Induced N-defective r prophages appear to be only poorly transcribed on strand H.Complementation tests performed in a strain lysogenic for indicate that the C17 mutation can suppress a r mutation in a cis position, even in the absence of the N-gene product.These results suggest that the expression of genes O and P, in addition to gene Q, is under the positive regulation of the N-gene product.  相似文献   

17.
M. G. Holmes  E. Schäfer 《Planta》1981,153(3):267-272
Detailed action spectra are presented for the inhibition of hypocotyl extension in dark-grown Sinapis alba L. seedlings by continuous (24 h) narrow waveband monochromatic light between 336 nm and 783 nm. The results show four distinct wavebands of major inhibitory action; these are centred in the ultra-violet (max=367 nm), blue (max=446 nm), red (max=653 nm) and far-red (max=712 nm) wavebands. Previous irradiation of the plants with red light (which also decreases Ptot) causes decreased inhibitory action by all wavelengths except those responsible for the red light inhibitory response. Pre-irradiation did not alter the wavelength of the action maxima. It is concluded that ultra-violet and blue light act mainly on a photoreceptor which is different from phytochrome.Abbreviations B blue - D dark - FR far-red - HIR high irradiance reaction - HW half power bandwith - Pr R absorbing form of phytochrome - Pfr FR absorbing form of phytochrome - Ptot total phytochrome=Pr+Pfr - R red - UV ultra violet  相似文献   

18.
Summary Defective transducing phages for the nalA region of the Escherichia coli chromosome were isolated from a lysogen in which is inserted in the nearby glpT gene. The three classes of transducing phages designated nrdA, dubiG, and dnalA contained bacterial DNA extending from glpT through nrdA, ubiG, and nalA, respectively. The bacterial genes are in the left arm of the chromosome. Of the eleven polypeptides coded by dnalA that were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate only one was not also specified by dubiG This 105,000 dalton polypeptide is the nalA gene product. The electrophoretic mobility and isoelectric point of this protein were unaffected by a nalA mutation (nalA48) that confers nalidixic acid resistance. Temperature-sensitive and amber mutations in the nalA gene were isolated using a dnalA48 lysogen which is heterodiploid for nalA. The conditional lethality of these mutations proves that nalA is an essential locus.  相似文献   

19.
Summary The purified bacteriophage replication proteins O and P sediment separately in metrizamide gradients of low ionic strength as dimers. Together they interact with each other forming an oligomer, composed of two molecules of O and one molecule of P. The O-P oligomer is active in the in vitro replication of ori-containing DNA.Equilibrium sedimentation in preformed metrizamide density gradients under conditions that separate DNA-protein complexes from free proteins was employed in order to study possible interactions among the replication proteins and ori DNA. It was found that the P protein binds specifically to ori-containing plasmid DNA only in the presence of O protein. About 100 molecules of O and 10 molecules of P form a complex with the ori DNA. The DNA-O-P complex was shown to be active in an in vitro replication system.Since the physical interactions between ori and O and between P and the Escherichia coli dnaB replication protein are well documented, the evidence for a O-P interaction presented in this paper provides the missing link in the molecular mechanism that enables to direct the host replication machinery to the replication of its own DNA.  相似文献   

20.
The goatfish Upeneus tragula undergoes an abrupt metamorphosis at settlement when the pelagic larvae begin a reef-associated benthic mode of life. A microspectrophotometric investigation of the retinal visual pigments was carried out on fish prior to, during, and following settlement. It was found that the visual pigment in the long wavelength-absorbing member of the double cones in the dorsal retina changed rapidly from a rhodopsin with a wavelength of maximum absorption (max) of 580 nm to that of 530 nm. The second member of the double cones always had a rhodopsin with the max absorbing at shorter wavelengths. Prior to settlement the average for this class of cones was 487 nm whereas during and immediately following the settlement period the max recorded from individual outer segments was found to vary between 480 nm and 520 nm, with two possible classes of cone absorbance emerging within this range. These two classes of absorbance had average max values of 487 and 515 nm. The average max of the paired cone classes in one larger wild-settled fish were found to be at 506 nm and 530 nm. No change was detected in the max of the single cones or the rods which were always found to have a max of about 400 nm and 498 nm respectively. The loss of the redabsorbing pigment occurred over the same time scale as the metamorphosis of morphological features associated with the settlement process. It is thought that the loss of this visual pigment is associated with the change in light environment of the fishes as they leave the surface waters to begin a benthic mode of life in deeper water.Abbreviations AIMS Australian Institute of Marine Science - ANOVA Analysis of variance - IR infra-red - max wavelength of maximum absorption - MSP microspectrophotometer - NA numerical aperture - SL standard length  相似文献   

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