Temporal shifts in visual pigment absorbance in the retina of Pacific salmon

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.     

Carbon isotope discrimination and foliar nutrient status of Larrea tridentata (creosote bush) in contrasting Mojave Desert soils

We investigated the relationships between foliar stable carbon isotope discrimination (), % foliar N, and predawn water potentials (_pd) and midday stomatal conductance (g _s) of Larrea tridentata across five Mojave Desert soils with different age-specific surface and sub-surface horizon development and soil hydrologies. We wished to elucidate how this long-lived evergreen shrub optimizes leaf-level physiological performance across soils with physicochemical characteristics that affect the distribution of limiting water and nitrogen resources. We found that in young, coarse alluvial soils that permit water infiltration to deeper soil horizons, % foliar N was highest and , g _s and _pd were lowest, while %N was lowest and , g _s and _pd were highest in fine sandy soils; Larrea growing in older soils with well-developed surface and sub-surface horizons exhibited intermediate values for these parameters. showed negative linear relationships with % N (R ²=0.54) and a positive relationship with _pd (R ²=0.14). Multiple regression analyses showed a strong degree of multicolinearity of g _s and with _pd and N, suggesting that soil-mediated distribution of co-limiting water and nitrogen resources was the primary determinant of stomatal behavior, which is the primary limitation to productivity in this shrub. These findings show that subtle changes in the soil medium plays a strong role in the spatial and temporal distribution and utilization of limiting water and nitrogen resources by this long-lived desert evergreen, and that this role can be detected through carbon isotope ratios.     

Sublittoral macrozoobenthic assemblages in the enclosed sediment-polluted Rhine-Meuse Delta; their relationship to environmental conditions

Composition, densities and biomass of sublittoral macrozoobenthos were investigated at 14 sites in the enclosed Rhine-Meuse Delta. The aim was to identify the main macrozoobenthic assemblages and to establish their relationship with environmental conditions, including sediment pollution. Most sites were dominated by the tubificidsLimnodrilus hoffmeisteri andL. claparedeanus. Four zoobenthic assemblages could be identified. They are related to different geomorphological phases of a basin filling up with fluvial sediment causing a longitudinal sediment gradient. The Rhine river assemblage was found in the Nieuwe Merwede, filled up in the 1970's, the soft mud assemblage in the Hollands Diep at sites with high sedimentation rates; the basin silt assemblage in the Amer, Hollands Diep and Haringvliet, at sites with lower sedimentation rates, and the basin shoal assemblage at former flats with low sedimentation rates. CANOCO was used to relate the TWINSPAN indicator species to a selection of environmental parameters. Sediment pH, water content, sand fraction, total polycyclic aromatic hydrocarbons (PAH) and current velocity explained 44% of the variance of the average abundance of the indicator taxa per site. Sediment firmness, indicated by sediment water content, and high ammonium concentrations probably were together responsible for the very low densities in the soft mud assemblage. Densities and biomasses in the other assemblages were low as well, except for theDreissena polymorpha habitat, where very high total zoobenthic biomass values (max. 55.8 g m^–2) were observed. It is argued that sediment contamination has a considerable impact on macrozoobenthic densities and species composition in all assemblages, the basin shoal assemblage excepted.     

The spectre of ‘spurious’ correlations

Summary Ecologists often standardize data through the use of ratios and indices. Such measures are employed generally to remove a size effect induced by some relatively uniteresting variable. The implications of using the resultant data in correlation and regression analyses are poorly recognized. We show that ratios and indices often provide surprising and spurious results due to their unusual properties. As a solution, we advocate the use of randomization tests to evaluate hypotheses confounded by spurious correlations. In addition, we emphasize that identifying the appropriate null correlation is of utmost importance when statistically evaluating ratios, although this issue is frequently ignored.     

Plant distribution in relation to the length of the growing season in a snow-bed in the Taisetsu Mountains,northern Japan

The distribution pattern of plants was studied in an alpine snow-bed in six plots along a snow-melting gradient. Each plot consisted of two habitats with respect to the microtopography; the flat habitat and the mound habitat. The number of species per plot decreased with the shortened snow-free period. In the flat habitat, the dominant growth forms changed from the early exposed plots to the late exposed ones as follows; lichens evergreen and deciduous shrubs forbs graminoids bryophytes. In the mound habitat, evergreen and deciduous shrubs prevailed widely along the gradient because of the ability to exploit new habitat by creeping over exposed rocks. For shrubs, the existence of mounds contributed to the expansion of the distribution ranges. Forbs and graminoids shifted their distribution modes to the late exposed plots where shrubs decreased in cover. Deciduous shrubs and forbs completely disappeared in the latest exposed plot.     

Frequent insectivory by two guenons (Cercopithecus lhoesti and Cercopithecus mitis) in the Kalinzu Forest, Uganda

I investigated the feeding ecology of lHoests monkeys (Cercopithecus lhoesti) and blue monkeys (Cercopithecus mitis) in the Kalinzu Forest, Uganda. Although forest guenons are generally thought to be frugivores or folivores, these two guenons spent a large proportion of their time feeding on invertebrates. The lHoests monkey and the blue monkey spent as much as 66 and 50% of their time on insectivory, respectively. These proportions of time spent on invertebrate feeding are higher than those reported elsewhere for forest guenons. LHoests monkeys mainly utilized the area near the ground for invertebrate feeding, while blue monkeys utilized the area around 20 m above the ground. It seemed that guenons have an ability to change their diet according to the environment.     

The wise use of wetlands: identifying development options for Ghana's coastal Ramsar sites

The Government of Ghana has recently declared five coastal wetlands to be Ramsar sites. This requires the wise use of wetlands of international importance for bird habitat, but does not preclude human habitation or ecologically friendly development. The sites are Muni-Pomadze, Densu Delta, Sakumo, Songor and Keta. An attempt was made to identify and assess a range of development options for initiation within the sites that would be compatible with the environmental concerns of Ramsar, while also being technically and economically viable and socially acceptable to the communities in the sites. The appraisal included developing a detailed understanding of the physical, biological, human and institutional resources of the areas, the land uses and prevailing livelihood systems of local people, and the pressures placed on the natural resources of the wetlands. Many of the developments nominated by stakeholders were rejected, but twenty topics passed the initial tests. These were considered in more detail using information collected for the study by national specialists. Most of the options were considered suitable for local level implementation by community groups or local entrepreneurs. Government assistance will be needed to ensure an enabling institutional framework for small-scale business development is provided.     

Monitoring organic enrichment of rivers using chironomid pupal exuvial assemblages

Exuvial samples were collected at stations above and below organic effluent inflows at twenty river sites near Bristol, England, during May, July and September, 1989.Exuvial sample data for each station were amalgamated and related to chemical data obtained from the Wessex and the Severn-Trent Regions of the National Rivers Authority. Principal Components Analysis (PCA) and Canonical Community Ordination (CANOCO) were used to derive biplots of taxa and selected environmental factors. From these biplots, lists of taxa were obtained, and ranked in order of closeness of association to selected organically-related environmental factors. Lists of principal taxa, either positively or negatively associated with a given environmental factor, were termed indicator assemblages in respect of that factor.The rank orders of similarity of these indicator assemblages to amalgamated exuvial samples from 51 stations on the River Trent, were significantly correlated (p<0.001) to the same stations ranked in order of ammonia concentrations and biological oxygen demand (BOD.).     

Analysis of transgene integration sites in transgenic pigs by fluorescence in situ hybridization

The production of pigs transgenic for human decay accelerating factor (hDAF) as potential donors for clinical organ xenotransplantation was reported several years ago. For this purpose it is required that high levels of hDAF are expressed at relevant sites in transplantable organs. Currently, homozygous lines have been produced as well as lines from crosses between heterozygous animals from different founder lines, termed jigsaw pigs. The purpose of the jigsaw crosses is to combine the desirable hDAF protein expression patterns found in different founder lines. Initial selection of the jigsaw pigs is based on the inheritance of the hDAF integration sites from both lines. Litters with potential homozygous transgenics and jigsaw transgenics were analysed by fluorescence in situ hybridization (FISH) and slot blot analysis. Results show that both slot blot analysis and FISH are suitable to distinguish between pigs that are heterozygous and homozygous for hDAF. However, FISH has the advantage of producing results more rapidly. For the identification of jigsaw pigs FISH analysis was required since slot blot analysis lacked the required accuracy. On basis of these results, FISH analysis was made part of the routine screening programme for hDAF transgenic pigs     

Macrofaunal diversity and habitat structure in intertidal boulder fields

Low-midshore boulder fields in Europe are increasingly subject to degradation related to beach fishing for crabs and abalones. The aim of the study was to better understand the structure and species diversity of macrofaunal assemblages living in a low-midshore boulder field in order to define conservation strategies for this biotope. Sampling strategy involved different spatial scales (macro- and microstrata) relative to the complexity and heterogeneity of the habitat. Assemblages of species and the corresponding habitats were identified by multifactorial analysis and compared by ANOVAs. The results show a hierarchical organization of the macrofauna within the boulder field, corresponding to three spatial levels of habitat structure: (i) eight microhabitats at the lowest level of spatial organization, each defined by a specific assemblage (subcommunity); (ii) three habitats at a middle level combining these microhabitats, each associated with a specific community (open rock, protected rock and sediment); and (iii) three macrohabitats at the uppermost level (corresponding to the scale of the entire boulder field and including the main geomorphological features of the beach), each defined by a specific assemblage of species (boulders on boulders, boulders on bedrock, and boulders on sediment). Two microhabitats with particularly high species diversity were regarded as the most important ecological units of the field in terms of conservation of specific and functional biodiversity. Comparison of habitat/community parameters showed (i) that habitat heterogeneity was not an accurate indicator of faunal diversity, and (ii) that habitat complexity enhanced the species richness of the fauna, but only above a threshold value. This enhancement was due to semi-sheltered microhabitats, which were found only in the most complex areas of the boulder field. It is likely that this complexity affects species richness qualitatively more than by the diversity of microhabitats. In other words, a cross-scale effect is apparent in which high habitat complexity on the middle spatial scale creates microhabitats on the lowest spatial scale that are characterized by stable semi-sheltered environmental conditions conducive to a maximum of species.     

The influence of habitat on the size distribution of groupers in the upper Florida Keys

Synopsis The influence of habitat on the size distribution of groupers was examined at sites in the middle and upper Florida Keys. Transects were used to quantify the size distribution of groupers at study sites. There were significant differences in the size distribution of groupers within and among reef community types related to differences in species composition and patch reef size. Groupers with a giant life-history style (Sullivan & de Garine 1994) were more abundant, but smaller, on inshore patch reefs than offshore reef community types. However, grouper species with a dwarf life-history style (Sullivan & de Garine 1994) showed an opposite pattern with a lower abundance, but larger size, inshore than offshore. The length category of groupers constituting the majority of individuals observed on patch reefs was inversely related to reef size. Graysby Epinephelus cruentatus were shown to recruit to deeper (15–20 m), low-relief habitats offshore. Several factors influenced the size distribution of groupers in the study sites including habitat type, spear-fishing, competition, predation, and recruitment.     

The frequency dependence of mating success in Drosophila melanogaster

In several competition experiments between various strains of Drosophila melanogaster, a rare female advantage as well as a rare male advantage has been observed. This phenomenon was detected by the use of a method described earlier (Lichtenberger et al., Behav. Genet. 17: 203–210, 1987). Often, the use of less refined indices does not lead to the same conclusion.This paper is dedicated to the memory of Dr Marcel Lichtenberger, M.D., fifteen years medical missionary in China, and seventeen years Professor of Human Genetics in the State University of Saigon, Vietnam.     

The Structures and Dynamics of Fish Communities in an Okinawan Coral Reef: Effects of Coral-based Habitat Structures at Sites with Rocky and Sandy Sea Bottoms

Although there have been many studies on ecological factors responsible for the organization of reef fish communities, most of the studies have focused on isolated habitats. However, findings from isolated habitats cannot necessarily be applied to fish communities in other habitats (e.g., a continuous habitat). In this study, therefore, we examined the structures of fish communities (abundance, species richness and species composition), and the dynamics of fish communities (seasonal changes in abundance, species richness and species composition) over a 2-year period in two different habitats (continuous habitat and isolated habitat) in an Okinawan coral reef. We established eight permanent quadrats (8m × 8m) on a rocky reef flat (continuous habitat) and rock reef patches surrounded by a sandy sea bottom (isolated habitat). The abundance and species richness of fishes such as pomacentrids, labrids, chaetodontids and acanthurids were greater in quadrats located in the continuous habitat, whereas those of blenniids, gobiids and mullids were greater in quadrats located in the isolated habitat. This caused marked differences between the fish community structure at the two sites. Seasonal and annual changes in fish community structure were relatively small at the continuous habitat site (>0.7 similarity based on C index) but were large at the isolated habitat site (C < 0.4), indicating that the fish community structure was relatively stable at the continuous habitat site but unstable at the isolated habitat site throughout the study period. Spatial differences between the fish community structures in the four quadrats at the continuous habitat site were small (C > 0.65 in most sites), but these differences were large at the isolated habitat site (C < 0.4). Our findings suggest that habitat structure (spatial arrangement of habitats) affects both spatial and seasonal differences in the reef fish community structure. The results also suggest that the main mechanisms underlying organization of reef fish communities in continuous and isolated habitats are different.     

Genetic analysis of brown planthopper resistance in twenty varieties of rice,Oryza saliva L.

Summary The inheritance of resistance to brown planthopper, Nilaparvata lugens (Stol.), of 20 rice cultivars was studied. Single dominant genes that are allelic to Bph 3 condition the resistance in cultivars Ptb 19, Gangala (Acc. 7733), Gangala (Acc. 15207), Horana Mawee, Kuruhondarwala, Mudu Kiriyal and Muthumanikam. Single recessive genes that are allelic to bph 4 govern the resistance in cultivars Gambada Samba, Heenhoranamawee, Hotel Samba, Kahata Samba, Kalukuruwee, Lekam Samba, Senawee, Sulai, Thirissa and Vellai Illankali. The resistance in Ptb 33, Sudu Hondarwala, and Sinna Sivappu is governed by one dominant and one recessive gene which segregate independently of each other. The dominant resistance genes in these cultivars appear allelic to either Bph 1 or Bph 3. Similarly, the recessive genes in these cultivars seem allelic to either bph 2 or bph 4. Further investigations are needed to conclusively determine the allelic relationships of resistance genes in Ptb 33, Sudu Hondarwala and Sinna Sivappu.     

The role of the invertebrate fauna in the biological assessment of water quality

Summary Observations of a correlation between the distribution of certain aquatic invertebrate species and different water pollution levels are — perhaps contrary to the expectation — not very recent. One could even say that such observations are older than ecology itself; as early as 1848 it was correctly concluded that the absence of caddis larvae from a stream can be caused by the presence of a city upstream (KOLENATI, 1848). The term ecology was blended in 1866 by Ernst Haeckel, together with a definition of the field to be studied by this new science.In the last decades of the 19th century these observations were more and more assembled into systems and methods to estimate water pollution levels and in 1908–1909 a first elaborated scheme for biological water quality assessment was published, the well-known Saprobiensystem (KOLKWITZ and MARSSON, 1908; 1909). In this system the range of organic pollution is divided into four levels and for every level a list of characteristic organisms is given; the invertebrate fauna is represented, but is only a fraction of all listed species. On basis of later investigations new indicative species were added to the list (LIEBMANN, 1960; SLADECEK, 1973).While the system was used more and more widely, a marked disadvantage was noticed, especially with respect to the invertebrate fauna, since the Saprobiensystem is a result of research in running waters in Central Europe. When sampling in other types of water (e.g. stagnant) or other parts of Europe one can meet two problems: (a) relatively few of the sampled species will be mentioned in the system as a consequence of either the limited geographical distribution of most invertebrate species or their limitation to running water; (b) those species mentioned in the system may have another behaviour towards pollution in not-running (or otherwise different) waters.In the past twenty years several large sampling programs have resulted in better adapted systems to estimate water quality on basis of invertebrate fauna (WOODIWISS, 1964; TUFFERY, and VERNEAUX, 1967; MOLLER PILLOT, 1972). One may conclude that the problem of limited geographical distribution of indicative species can be solved by constructing different systems for zoogeographically too different regions. Too different means in this context so different that a saprobic system on the taxonomical level of the species cannot be suitable for both regions by sheer lack of common organisms. On a higher taxonomical level (genera or families) it may be possible to construct a system with a very broad applicability, but the degree of resolution with respect to pollution levels may not be very high in this case.The second problem-restriction of species to certain types of water-could be dealt with in a similar way,i.e. a Saprobiensystem for every type of water. The almost philosophical problem of defining what a type is, should be avoided for practical purposes by adopting a tractable number of easily recognizable types and accepting the fact that a saprobic system loses its applicability for the more extreme representatives of a type. Some types of water may be found, for instance large open water, where invertebrate fauna is not a very convenient group for water quality assessment. On the other hand, types of water where invertebrates are virtually the only group present also exist (glacier streams). In general the group seems to be highly suitable for the estimation of organic pollution in many kinds of surface water (limnosaprobity,sensu SLADECEK, 1973).Apart from saprobity there are some other properties of surface waters that can be faunistically detected and/or characterized. (a) Nutrient status (oligotrophic, eutrophic, etc.). However, invertebrate species with a clear preference for a specific nutrient level are not very numerous as compared to phytoplankton or macrophytes. (b) Integrity or other criteria to express the extent to which the potential biological richness of a geomorphologically defined type of water is realized. This can be important when an indication is wanted of the value of an aquatic ecotope as compared to other representatives of the type. Again, knowledge of the optimal biological development is needed as a reference, as in the case of a saprobic system.Thus, a typology or classification of types of water, accompanied by some sort of indication about the optimal (often natural) situation, would not be a purely scientific topic. A classification can serve as a basis for the monitoring as well as the evaluation of aquatic ecotopes (MOL, 1977; 1979). The large number of species and the vast geographical and typological distribution of aquatic invertebrates justifies the expectation that the group will play an important part in any biological classification of surface waters.     

Genetic diversity in relation to heterosis and combining ability in spring wheat

Summary Genetic diversity among ten varieties of spring wheat used as parents in a diallel cross was assessed through multivariate analysis (D²-statistics) and then related to heterosis and SCA effects of their hybrids. The parents fell into three groups. Group I contained the varieties, Nobre, Girua and Carazinho; group II contained Sonalika, Lyallpur and Pitic 62 and group III contained Indus 66, Balaka, Sonora 64rs and MSl. The varieties of group I were good general combiners, while the varieties of group III were poor combiners. Significant heterotic and SCA effects for yield and yield components were observed in the hybrids of the parents belonging to different groups but not in the same group. Genetic divergence between the parents had a positive relationship with heterosis and SCA effects of the hybrids.     

Adoptions expérimentales de larves entre des fourmis de genres différents:Leptothorax nylanderi Förster etSolenopsis fugax Latreille

Résumé En l'absence de son propre couvain,Solenopsis fugax a élevé des larves deLeptothorax nylanderi, à la température de 22°C. Les ouvrières deSolenopsis détruisirent une partie de ces larves mais nourrirent celles qu'elles épargnèrent; ces dernières grossirent lentement pendant cinq à six mois, sans atteindre le stade prénymphe. Lorsque les ouvrières deS. fugax et les larves deL. nylanderi furent soumises ensemble à un hivernage préalable, elles donnèrent les mêmes résultats que sans hivernage. La présence d'une jeune reine deSolenopsis fut défavorable aux larves deLeptothorax.Inversement,L. nylanderi fut capable d'élever, à la température de 22°C, des larves deS. fugax et de les amener jusqu'au stade adulte. En présence de leurs propres larves, les ouvrières deL. nylanderi détruisirent tapidement toutes les larves deS. fugax introduites dans leur nid. D'autre part, un jeune couvain deLeptothorax remplaçait plus ou moins rapidement les larves deLeptothorax enlevées au préalable; sa présence était alors défavorable au développement des larves deSolenopsis. Un hivernage en début d'expérience fut plutôt favorable auxS. fugax, de même que la présence d'une reine féconde deLeptothorax. LesSolenopsis ainsi obtenus n'ont pas vécu plus de sept semaines. Ils étaient tous de caste ouvrière et de taille très petite.

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Summary When its own eggs and larvae missed,Solenopsis fugax bred larvae ofLeptothorax nylanderi, at a temperature of 22°C. TheSolenopsis workers killed some of this larvae and fed the others; these slowly grew bigger during five or six months but never reached the pre-pupa stage. The result was the same if the workers ofS. fugax and the larvae ofL. nylanderi overwintered together or not at all. A youngSolenopsis queen being there was noxious to the larvae ofLeptothorax.On the contrary,L. nylanderi has been able to breed larvae ofS. fugax up to the imago stage, at a temperature of 22°C. When its own larvae were in the nest, together with larvae ofS. fugax, the workers ofL. nylanderi killed the larvae ofS. fugax. On the other hand, new eggs and young larvae ofLeptothorax had to replace, more or less quickly, the larvae which had been taken away, and that was noxious to the growth ofSolenopsis larvae. An overwintering at the beginning of the experiment was rather favourable toS. fugax as was the presence of a fecundLeptothorax queen. TheSolenopsis thus obtained lived no longer than seven weeks. They all were workers and very small.

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S. Fugax L. Nylanderi 22° . Leptothorax , , , , . . S. Fugax Leptothorax.,L. Nylanderi 22° S. Fugax . L. Nylanderi ( )Leptothorax ; S. Fugax Solenopsis, Leptothorax. S. Fugax . .

     

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 .

     

High D-glucose does not affect binding of α-tocopherol to human erythrocytes

The role of -tocopherol uptake system in human erythrocyte in the uptake of plasma -tocopherol has been suggested. However no information is available on -tocopherol uptake activity of human erythrocytes in the presence of high levels of D-glucose which is known to lead to pathological alterations in different cells including human erythrocytes. Therefore, in order to examine the effect of D-glucose on the binding of -tocopherol to human erythrocytes, the binding characteristics of -tocopherol to these cells were established first. Binding of [3H]-tocopherol to human erythrocytes was both saturable and specific. Scatchard analysis of -tocopherol binding to these cells showed the presence of two independent classes of binding sites with widely different affinities. The high affinity binding sites had a dissociation constant (Kd1) of 90 nM with a binding capacity (n1) of 900 sites per cell, whereas the low affinity binding sites had a dissociation constant (Kd2) of 5.2 M and a binding capacity (n2) of 105,400 sites per cell. Trypsin treatment abolished all the -tocopherol binding activity. Competition for the binding of -tocopherol to human erythrocytes was effective with other homologues of -tocopherol (-tocopherol, -tocopherol and -tocopherol) and their potency was almost equal to -tocopherol itself. The order of preference was -tocopherol > -tocopherol -tocopherol -tocopherol. Incubation of human erythrocytes with various concentrations of D-glucose did not affect -tocopherol uptake activity. Our data demonstrate the presence of an -tocopherol uptake system in human erythrocytes and that the -tocopherol uptake activity is not modulated by the presence of D-glucose.     

Affinity Profiles of Novel δ-Receptor Selective Benzofuran Derivatives of Non-Peptide Opioids

Highly selective heterocyclic opioid ligands with potent -antagonist activity have been developed on the basis of the message-address concept. Using this strategy, benzofuran derivatives corresponding to the non-selective opioid antagonist, naloxone, and to the -opioid receptor selective agonists, oxymorphone and oxycodone, were synthesized. In vitro opioid receptor binding profiles and agonist/antagonist character of these compounds were determined in rat brain membrane preparations with highly selective radioligands. All three benzofuran derivatives displayed high affinities for the -opioid receptor, much less potency toward the -binding site, and were the least effective at the -site. The results indicated that the addition of the bezofuran moiety to these fused ring opioids confers -receptor selectivity. The Na⁺ indices suggested a partial agonist character for oxymorphone- and oxycodone-benzofuran, and an antagonist character for naloxone-benzofuran. These compounds were capable of irreversible inhibition of opioid binding sites in a dosedependent.