Interneuronal and glial-neuronal gap junctions in the lamina ganglionaris of the compound eye of the housefly,Musca domestics

Summary The cell-body layer of the lamina ganglionaris of the housefly, Musca domestica, contains the perikarya of five types of monopolar interneuron (L1–L5) along with their enveloping neuroglia (Strausfeld 1971). We confirm previous reports (Trujillo-Cenóz 1965; Boschek 1971) that monopolar cell bodies in the lamina form three structural classes: Class I, Class II, and midget monopolar cells. Class-I cells (L1 and L2) have large (8–15 m) often crescentshaped cell bodies, much perinuclear cytoplasm and deep glial invaginations. Class-II cells (L3 and L4) have smaller perikarya (4–8 m) with little perinuclear cytoplasm and no glial invaginations. The midget monopolar cell (L5) resides at the base of the cell-body layer and has a cubshaped cell body. Though embedded within a reticulum of satellite glia, the L1–L4 monopolar perikarya and their immediately proximal neurites frequently appose each other directly. Typical arthropod (-type) gap junctions are routinely observed at these interfaces. These junctions can span up to 0.8 m with an intercellular space of 2–4 nm. The surrounding nonspecialized interspace is 12–20 nm. Freezefracture replicas of monopolar appositions confirm the presence of -type gap junctions, i.e., circular plaques (0.15–0.7 m diam.) of large (10–15 nm) E-face particles. Gap junctions are present between Class I somata and their proximal neurites, between Class I and Class II somata and proximal neurites, and between Class II somata. Intercartridge coupling may exist between such monopolar somata. The cell body and proximal neurite of L5 were not examined. We also find that Class I and Class II somata are extensively linked to their satellite glia via gap junctions. The gap width and nonjunctional interspace between neuron and glia are the same as those found between neurons. The particular arrangement and morphology of lamina monopolar neurons suggest that coupling or low resistance pathways between functionally distinct neurons and between neuron and glia are probably related to the metabolic requirements of the nuclear layer and may play a role in wide field signal averaging and light adaptation.     

Purification and initial characterization of phycobiliproteins from the endophytic cyanobacterium of Azolla

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     

Intracellular responses from the photosensitive pineal organ of the teleost,Phoxinus phoxinus

Summary Intracellular potentials from the isolated dark-adapted pineal organ ofPhoxinus phoxinus were recorded by using glass microelectrodes. The majority of cells had resting potentials of 20 to 35 mV and responded to light with intensitygraded hyperpolarizations. Voltage intensity curves of responses to brief flashes followed the hyperbolic tangent functionV/V _max=Iⁿ/(I ⁿ + ⁿ ).The latency of onset for responses to light stimuli near threshold was 400 ms and decreased with saturating flashes to about 50 ms. The membrane resistance decreased during the hyperpolarization. Spectral sensitivity measurements for these cells exhibited curves with _max=530 nm. Intracellular dye injection unequivocally identified this cell type as a photoreceptor cell.A second cell type with resting potentials between 30 to 40 mV exhibited a biphasic response pattern to light stimulation. The cell depolarized with dim light flashes and hyperpolarized with bright flashes. The amplitude of the hyperpolarizing component showed no saturation over an intensity range of 5 log units. Latencies and rise times were comparable to those of photoreceptor potentials. Spectral sensitivity curves peaked at longer wavelengths ( _max=550 nm) than the action spectra of photoreceptors ( _max=530 nm). It is assumed that this rare cell type represents a small class of pineal interneurons.     

Visual pigments and oil droplets in the penguin,Spheniscus humboldti

Summary The photoreceptors of the penguin,Spheniscus humboldti, were examined using a microspectrophotometer. The cones could be divided into three classes based on their visual pigment absorbance spectra [max 403, 450 and 543 nm (Fig. 1)], and into five classes based on their visual pigment-oil droplet combination (Fig. 4). Oil droplets were of three types (Fig. 2). The rods contained a rhodopsin with max at 504 nm. No double cones were observed. The penguin should be capable of good wavelength discrimination in the blue-green region of the spectrum but with poor discrimination at longer wavelengths. It is concluded that the spectral properties of the cone types indicate that the photopic vision ofS. humboldti is adapted to the spectral qualities of its aquatic environment.     

Intraspecific variation of spectral sensitivity in threespine stickleback (Gasterosteus aculeatus) from different photic regimes

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.     

The spectral input systems of hymenopteran insects and their receptor-based colour vision

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.     

The responses of one class of neurons in the optic tract of crayfish (Procambarus) to monochromatic light

Summary Spectral sensitivity curves for four sustaining neurons in the optic tracts of Procambarus clarkii were determined under dark-adapted and chromatic light-adapted conditions. The _max in the dark-adapted state is at 570 to 575 nm, and shifts to longer wavelengths in the violet-light-adapted state (Fig. 4). Red-light-adaptation suppresses the sensitivity of the yellow-green receptors of the eye and alters the discharge pattern of the sustaining neurons, thereby exposing an input with a _max at 445 nm from the blue-sensitive receptors (Fig. 5). Such data raise the possibility that sustaining neurons may carry information that functions in color vision.This work was supported by a predoctoral fellowship FO1-GM-31,230 and then a training grant 2TO1-GM00836 to D.L.T. and grant NB-05423 to J.L.L. and Biomedical Sciences Support Grant 5-S05 FR-07091, all from the U.S.P.H.S.     

Spectral sensitivity of visual cells of the compound eye ofBlatta orientalis

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.     

Genes encoding acidic and basic class III β-1,3-glucanases are expressed in tomato plants upon viroid infection

-1,3-glucanases are hydrolytic enzymes considered to constitute part of the general array of defense genes induced by pathogen infection in higher plants. We have isolated and characterized two complementary DNA clones, corresponding to new -1,3-glucanases from tomato plants (Lycopersicon esculentum) which are expressed upon challenge with citrus exocortis viroid. Amino acid sequence comparison revealed that they are most similar to -1,3-glucanases from tobacco, particularly to PR-Q, the unique component of the class III -1,3-glucanase. The deduced amino acid sequences of the two tomato -1,3-glucanases indicate that, although being highly similar in amino acid sequence, they have different isoelectric points: pI 10.5 for the basic isoform (Tom PR-Q b) and pI 5.2 for the acidic one (Tom PR-Q a). The expression of these two -1,3-glucanase messenger RNAs (mRNAs) in response to viroid infection and ethephon treatments was examined. mRNAs for these two isoforms are coordinately expressed and induced similarly to mRNAs for other PR proteins, indicating that they are part of a general and coordinate mechanism of response of tomato plants susceptible to viroid infection.     

Assessment of membrane potential changes using the carbocyanine dye,diS-C3-(5): synchronous excitation spectroscopy studies

The fluorescence of the voltage sensitive dye, diS-C₃-(5), has been analyzed by means of synchronous excitation spectroscopy. Using this rather rare fluorescence technique we have been able to distinguish between the slightly shifted spectra of diS-C₃-(5) fluorescence from cells and from the supernatant. It has been found that diS-C₃-(5) fluorescence in the supernatant can be selectively monitored at _exc = 630 nm and _em= 650 nm, while the cell associated fluorescence can be observed at _exc= 690 nm and _em = 710 nm. A modified theory for the diSC₃-(5) fluorescence response to the membrane potential is presented, according to which a linear relationship exists between the logarithmic increment of the dye fluorescence intensity in the supernatant, In I/I°, and the underlying change in the plasma membrane potential, _p=_p-°_p. The theory has been tested on human myeloid leukemia cells (line ML-1) in which membrane potential changes were induced by valinomycin clamping in various K⁺ gradients. It has been demonstrated that the membrane potential change, _p,can be measured on an absolute scale. Offprint requests to: J. Plasek     

Die bursa- und schwanzstrukturen und ihre aberrationen bei den strongylina (Nematoda) morphologische studien zum problem der pluri-und paripotenzerscheinungen

Zusammenfassung In der Einleitung ist das Ziel der Arbeit in den wesentlichsten Punkten herausgestellt.Die Bursastrukturen (Bursavelum und Rippen bzw. Papillen) der parasitischen Strongylina lassen sich von den entsprechenden Bildungen der freilebenden Rhabditina, vor allem der Gattung Rhabditis, ableiten und in ihren Einzelgliedern homologisieren.Die im Laufe der Phylogenie bei den Strongylina auftretenden strukturellen Transformationen lassen sich auf einige wenige, relativ einfache morphogenetische Grundvorgänge zurückführen, die da sind: Wachstumsallometrien, Materialkompensationen, Organverschmelzungen und Spaltungen (Fissationen), Rudimentationen und ähnliche Vorgänge.Innerhalb der Strongylina Bursa ist ein Gefälle der Wachstumsgradienten feststellbar, das sich vom Zentrum der Bursa sowohl nach distal als auch proximalwärts abschwdcht. Zunehmende Förderung der zentral gelegenen Organe (Rippen) führt zu entsprechender Reduktion der peripheren Bursastrukturen, was vor allem im terminalen Schwanzabschnitt auffällt und zur Ausbildung des oft nur noch als Rudiment vorhandenen Dorsalrippenkomplexes führt. Letzterer entspricht in seiner Gesamtheit der Schwanzspitze der peloderen Rhabditiden mit den Papillen 9 und 10.Die bei Rhabditis moist getrennten Papillen 7 und 8 sind bei allen Strongylina zu einer Rippe (Externodorsal-Rippe) verschmolzen, die jedoch in manchen Aberrationen durch Abspaltung eines akzessorischen Astes ihre wahre Natur (als Verschmelzungsprodukt) zu erkennen gibt (Atavismus).Da dieselben Transformationsvorgänge innerhalb der Strongylina mehrfach unabhängig voneinander wirksam geworden sind, treten bestimmte Strukturformen als Parallelbildungen in verschiedenen phylogenetischen Union auf (polytope Entstehung).Zahlreich untersuchte Bildungsabweichungen (Aberrationen), deren Bedeutung für die Morphologie kurz umrissen wird, erschöpfen sich in den gleichen strukturellen Transformationstypen, die auch bei der Evolution der verschiedenen Union der Strongylina nachweisbar sind. Die Aberrationen führen daher häufig zu Atavismen oder zu Parallelvariationen (homologe Variationen").Die Zahl der Umwandlungsmbglichkeiten (Potenzen) der Bursastrukturen innerhalb der Strongylina ist beschränkt (Paripotenz im Sinne Haeckers). Bestimmte Arten (und Entwicklungshnien) haben jeweils nur bestimmte Potenzen realisiert. Andere können jedoch latent (virtuell) im Kryptotypus vorhanden sein, ohne normalerweise in Erscheinung. zu treten. In bestimmten Aberrationen können sie jedoch plötzlich realisiert werden, so ihr latentes Vorhandensein demonstrierend (Pluripotenz).Wie lange bestimmte Potenzen in einer Gruppe erhalten bleiben konnen, verdeutlichen auch die Schwanzhocker weiblicher Nematoden, als zum Bauplan der Nematoden gehbrende Bildungen. Die Potenz zur Ausbildung dieser Strukturen kommt offensichtlich sehr vielen Nematoden-Arten zu, wird jedoch nur in relativ wenigen Fällen, aber innerhalb der verschiedenen Gruppen bald hier, bald dort (disjunkte Verbreitung), realisiert. Es handelt sich bei den Schwanzhöckern um rudimentäre Organe, die bei keiner Nematoden-Art mehr voll ausgebildet erhalten sind. Ihre Rudimentation beruht zum Teil auf Materialentzug, als Folge von Unkonstruktionen der Schwanzregion, wobei die Adultstadien zuerst betroffen werden (Aphanisie nach Sewertzoff).Bei den in Chiropteren parasitierenden Strongylacanthinae haben sich Schwanzhöcker noch bei allen Arten erhalten, was ein offensichtlich archaisches Merkmal darstellt. Bei anderen Nematoden, denen sie nur im Larvalstadium zukommen, treten sie wohl durch Fötalisation in seltenen Fällen auch bei den adulten Stadien wieder auf.Alle speziellen Bursaformen der Strongylina lassen sich durch relativ wenige und einfache Transformationsvorgänge aus einem durch Abstraktion gewonnenen diagrammatischen Typus ableiten (Prinzip der variablen Proportionen" nach Troll).Die typisierten Umwandlungsvorgänge decken sich weitgehend mit den von Remane allgemein gefaßten strukturellen Typen der Realmutationen. Da sie bei den beobachteten Aberrationen, deren Entstehung auf dem Wege über Realmutationen sehr wahrscheinlich ist, in homologer Weise auftreten, kann das innerhalb der Strongylina zu beobachtende Evolutionsphänomen auf Realmutationen zurückgeführt warden.Obwohl sich die untersuchten strukturellen Transformationen in dem systematisch relativ wait gefaßten Rahmen einer Unterordnung abspielen (transspezifische Evolution nach Rensch), handelt es sich bei der von uns bevorzugten Terminologie (nach Woltereck und Remane), unter Berücksichtigung des Charakters der Umwandlungen, doch nur um Vorgänge, die in den Bereich der Mikroevolution fallen.     

Interspecific variation in the visual pigments of deep-sea fishes

Summary Visual pigments in the rods of 38 species of deep-sea fish were examined by microspectrophotometry. 33 species were found to have a single rhodopsin with a wavelength of maximum absorbance ( _max) in the range 470–495 nm. Such visual pigments have absorbance maxima close to the wavelengths of maximum spectral transmission of oceanic water. 5 species, however, did not conform to this pattern and visual pigments were found with _max values ranging from 451 nm to 539 nm. In 4 of these species two visual pigments were found located in two types of rod. Some 2-pigment species which have unusual red sensitivity, also have red-emitting photophores. These species have both rhodopsin and porphyropsin pigments in their retinae, which was confirmed by HPLC, and the two pigments are apparently located in separate rods in the same retinal area. In deep-sea fishes the occurrence of unusual visual pigments seems to be correlated with aspects of the species' depth ranges. In addition to ecological influences we present evidence, in the form of _max spectral clustering, that indicates the degree of molecular constraint imposed on the evolution of visual pigments in the deep-sea.     

Spatio-temporal patterns of photosystem II activity and plasma-membrane proton flows in Chara corallina cells exposed to overall and local illumination

Pulse-amplitude modulated microfluorometry and an extracellular pH microprobe were used to examine light-induced spatial heterogeneity of photosynthetic and H⁺-transporting activities in cells of Chara corallina Klein ex Willd. Subcellular domains featuring different PSII photochemical activities were found to conform to alternate alkaline and acid zones produced near the cell surface, with peaks of PSII activity correlating with the position of acid zones. Buffers eliminated pH variations near the cell surface but did not destroy the variations in PSII photochemical yield (F/F_m). When a dark-adapted cell was exposed to actinic light, the PSII effective yield decreased within 5–15 min in the alkaline regions but rose after the initial decline in the acid regions. The light-induced decrease in F/F_m in the alkaline regions occurred prior to or synchronously with the steep rise in local pH. The kinetics of F/F_m, F_m, and F observed in alkaline regions under overall illumination of Chara cells were replaced by those typical of acid regions, when the illumination area size was restricted to 1.5–2 mm. The data show that photoinduced patterns in photosynthetic activity are not predetermined by the particular structural organization of alkaline and acid cell regions but are subject to dynamic changes.Abbreviations APW artificial pond water - a.u. arbitrary units - F_o and F_m minimal and maximal chlorophyll fluorescence yields in a dark-adapted cell - F and F_m actual (running) and maximal fluorescence yields in a cell exposed to actinic light - F/F_m(F_m–F)/F_m effective quantum yield of PSII photochemistry - pH_o pH of the medium near the cell surface - PSII photosystem II     

Modelling oil droplet absorption spectra and spectral sensitivities of bird cone photoreceptors

Birds have four spectrally distinct types of single cones that they use for colour vision. It is often desirable to be able to model the spectral sensitivities of the different cone types, which vary considerably between species. However, although there are several mathematical models available for describing the spectral absorption of visual pigments, there is no model describing the spectral absorption of the coloured oil droplets found in three of the four single cone types. In this paper, we describe such a model and illustrate its use in estimating the spectral sensitivities of single cones. Furthermore, we show that the spectral locations of the wavelengths of maximum absorbance (_max) of the short- (SWS), medium- (MWS) and long- (LWS) wavelength-sensitive visual pigments and the cut-off wavelengths (_cut) of their respective C-, Y- and R-type oil droplets can be predicted from the _max of the ultraviolet- (UVS)/violet- (VS) sensitive visual pigment.     

Effects of background adaptation on α-MSH and β-endorphin in secretory granule types of melanotrope cells of Xenopus laevis

Placing the clawed toad Xenopus laevis on a black background stimulates the melanotrope cells in the pars intermedia of the pituitary gland to release proopiomelanocortin (POMC)-derived peptides, including -MSH and N-acetyl-endorphin. In this study three types of secretory granules, electron-dense(130 nm Ø), moderately electron-dense ( 160 nm Ø) and electronlucent ( 180 nm Ø), have been identified in these cells. Apparently, only dark granules are formed by the Golgi apparatus and lucent granules release their contents via exocytosis. Immuno-electron microscopy (immunogold double labelling) of glutaraldehyde-fixed and freeze-substituted material shows that desacetyl--MSH and N-acetyl--endorphin coexist in all three granule types. Quantification of immunostaining revealed that immunoreactivities to these peptides are lowest in the dark granules and highest in the light ones. It is proposed that intragranular processing of POMC to immunoreactive desacetyl--MSH and N-acetyl--endorphin involves an increase in granule size and a decrease in granule electron density. Black background-induced activation of the melanotrope cell is reflected by an increase in immunoreactivity of the secretory granules to each of the antisera. This suggests that cell activation stimulates the formation of peptides by intragranular processing of POMC and/or of intermediate POMC-processing products. In addition, cell activation evoked an increase in the percentage of the granule population that reacts with anti-N-acetyl--endorphin, probably by stimulating intragranular acetylation of -endorphin. Apparently, this acetylation is a regulated event that occurs in the cytoplasm, independently from the acetylation of desacetyl--MSH which takes place near the plasmalemma at the time of granule exocytosis.     

Blue through UV polarization sensitivities in insects

A Signal-to-Noise optimization model has now been extended to explain the range of species-specific polarization sensitivities of insects. The different polarization sensitivities are shown to represent optimizations for the detection of plane polarized (Rayleigh-scattered) skylight over a range of atmospheric polarization conditions. Rhodopsin absorption spectra with peaks in the Blue (max450 nm) maximize detection efficiencies under conditions of high polarization. Rhodopsin absorption spectra peaking in the UV (max350 nm) maximize Signal-to-Noise Ratios for the detection of polarized skylight at the other extreme of low polarization.     

Aspects of color vision in bluegill sunfish (Lepomis macrochirus): ecological and evolutionary relevance

Summary Spectral sensitivity curves were measured for bluegills using a heart-rate conditioning technique. A mean spectral sensitivity curve (n=3) determined using a white background exhibited two main peaks, indicating the possible presence of two cone photoreceptors mechanisms. Chromatic adaptation was used to separate the contribution of the cone mechanisms to sensitivity. Peak sensitivities were located at 540 and 640 nm against red and blue-green backgrounds, respectively.Light adaptation curves were measured for each cone mechanism indicating that these cone mechanisms have their greatest contrast sensitivity at higher background intensities. Spatial summation properties were also measured for each cone mechanism revealing a critical diameter (summation area) of 5° for both mechanisms.Microspectrophotometric (MSP) measurements were made on individuals from the same group of bluegills used in the above experiments. The results showed the presence of two cone types: single green-sensitive cones with an average _max of 536 nm (SD±1.8nm,n=11) and twin redsensitive cones with an average _max of 620 nm (SD ±1.9 nm,n=11).The correlation between the visual pigment absorption spectra and action spectra of the two cone mechanisms indicate a sound physiological basis for sensitivity. The functional properties of the two cone mechanisms, will be discussed in relation to the ecological and behavioral aspects of bluegills.Abbreviation TVI threshold vs intensity     

The expression and biological activity of IL-2 receptor on a human pancreas cancer cell line

To ascertain whether the tumor cells can regulate the host immune systems through the production of the cytokines or their receptors, we examined the expressions of tumor necrosis factor (TNF), tumor necrosis factor (TNF), interleukin 2 (IL-2) and interleukin 2 receptor alpha chain (IL-2R) on the human cancer cell lines by Northern blot analysis. We used K562 (leukemia cell line), MCF-7 (breast cancer cell line), LS180, HT29 (colon cancer cell lines), SH101 (gastric cancer cell line) and PH101 (pancreas cancer cell line). Expressions of TNF, TNF and IL-2 mRNA were not detected in any of the tumor cell lines. However, 1.4 and 3.5 kilobases of the IL-2R mRNA were expressed in the PH101 cells, but not in the other five cell lines. Furthermore, IL-2R was detected on the cell surface of the PH101 cells by the flow-cytometric analysis with an anti-IL-2R monoclonal antibody. Interestingly, the soluble IL-2R (sIL-2R) was found in the conditioned media obtained from the PH101 cell culture with a sandwich enzyme immunoassay. Moreover, the sIL-2R secreted from the PH101 cells blocked the IL-2 dependent lymphocyte proliferation. These results indicate that the expression of IL-2R on PH101 might suppress the IL-2 induced lymphocyte proliferation.     

Fluorescence and reflectance characteristics of manganese deficient soybean leaves: Effects of leaf age and choice of leaflet

Leaf reflectance and fluorescence characteristics of soybean (Glycine max cv Bragg) are influenced strongly by Mn availability. This report evaluates the effects of leaflet choice, leaf age, and leaf nodal position on several spectral characteristics. Leaves were obtained from soybeans grown hydroponically under controlled environmental conditions with wide differences in Mn supply. The ratio of constant yield fluorescence (F_o) to variable yield fluorescence (F_v), the ratios of reflectance at 750 nm to 550 nm and that at 650 nm to 550 nm, the position of the "red edge" near 700 nm, and an index of leaf "yellowness" were measured periodically. Increasing leaf age caused increases in the "red edge" and in both reflectance ratios. Leaf "yellowness" and the fluorescence ratio F_o/F_v decreased with leaf age and increased with leaf nodal position, primarily in Mn deficient leaves. Effects arising from leaf choice were smaller than those caused by Mn deficiency.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .