UDP-galactose:lactosylceramide α-galactosyltransferase activity in human placenta

The activity of UDP-Gal: LacCer galactosyltransferase in human placenta was studied by using crude homogenate and Triton CF-54 extract as the source of enzyme. Transfer of galactose to lactosylceramide was optimal in the presence of 0.1% Triton CF-54 and Mn²⁺ at pH 6.3, and the reaction product was susceptible to -galactosidase.Abbreviations LacCer lactosylceramide (Gal1-4Glc1-1Cer) - Gb₃ globotriaosylceramide (Gal1-4Gal1-4Glc1-1Cer) - Gb₄ globoside (GalNAc1-3Gal1-4Gal1-4Glc1-1Cer) - TLC thin-layer chromatography - GC/MS gas chromatography/mass spectrometry - NMR nuclear magnetic resonance - EDTA ethylenediamine tetraacetic acid - CHAPS 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate     

Carboxyl-terminal modification alters the subunit interactions and assembly pathways of normal and sickle hemoglobins

Parallel isofocusing studies established that carboxypeptidase A removal of the His-146 (HC3) and Tyr-145 (HC2) residues of heme subunits affected the assembly properties of both Des (A) and Des (S) with heme chains, albeit to differing degrees. Indeed, the rate of Des (A) oligomer dissociation (k ₁), as determined by visible spectroscopy, was 4.3-fold faster than that of its native (A) counterpart. Furthermore, Soret spectral studies have affirmed distinct rates of normal (HbA), sickle (HbS), and Des HbA hemoglobin assembly (k₂) from their and [Des (A)] heme-containing monomers. Matching kinetic analysis of Des (A) and Des (S) chain assembly (with an identical chain) revealed 4.6- and 7.8-fold faster combination rates than those seen for (A) and (S) chains, respectively. This 3-fold disparity in rates strongly supports the critical role of the -6 (A3) residue, and its amino-terminal region, in chain partner recognition and subsequent human hemoglobin assembly.     

A comparison and evaluation of some phytosociological techniques

Summary In three areas of vegetation (dune, mountain heath and salt marsh) the following phytosociological techniques have been tested and compared, using the same data: the Braun-Blanquet method; association and inverse analysis ofWilliams &Lambert; cluster analysis (agglomerative classification) based on different coefficients of similarity; and ordination (principal components analysis performed on matrices of different coefficients).The Braun-Blanquet method is considered to combine several advantages of the other methods and to be most economical in terms of efficiency (ratio of time input to information emerging).

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Zusammenfassung Auf drei verschiedenen Vegetationsflächen (Bergheide, Küstendünen und Salzwiesen) sind die folgenden pflanzensoziologischen Methoden geprüft und verglichen worden: die Methode von Braun-Blanquet; association analysis vonWilliams &Lambert (1959, 1961); Ordination (principal components analysis); und cluster analysis (Sokal &Sneath, 1963). Die letzteren beiden wurden mit verschiedenen Ähnlichkeitskoeffizienten geprüft.Auf Grund solchen Erfahrungen, zeigte sich die Braun-Blanquetische Methode leistungsfähiger als die anderen Methoden (d.h. optimale Einsicht in der Vegetation pro Arbeitsstunde). Sie vereinigte viele Vorteile der anderen Methoden.

     

Working with Jewish ultra-orthodox patients: Guidelines for a culturally sensitive therapy

The epistemological gap between the medical reality of mental health practitioners and the sacred reality of their Jewish ultra-orthodox patients poses a major challenge for therapy. Based on our work with psychiatric patients from the ultraorthodox community of northern Jerusalem, we propose a set of guidelines to cope with this challenge. Basically, we seek to incorporate religiously congruent elements, composed of metaphoric images, narratives and actions, into the wide range of our secular treatment modalities in order to respond to the patient's suffering, often expressed through distinctively religious idioms of distress. This endeavor calls for a temporary suspension of disbelief on both sides.The guidelines presented include three sets of factors which appear pertinent to working with ultra-orthodox patients. The first set is contextual in nature, dealing with the image of the clinic and its physical setting; the second discusses the necessary role requisites of the therapists; and the third one, accorded a central importance, deals on various levels with the therapeutic interventions administered in terms of form and content. Several case vignettes are presented to illustrate three classes of religiously informed interventions: healing rituals, dream interpretation, and the use of culturally congruent metaphors and stories. In the concluding part we discuss ethical and instrumental issues that the proposed therapeutic guidelines may raise.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

The effect of humidity and light on cellular water relations and diffusion conductance of leaves ofTradescantia virginiana L.

Turgor (_p) and osmotic potential (_s) in epidermal and mesophyll cells, in-situ xylem water potential (-xyl) and gas exchange were measured during changes of air humidity and light in leaves ofTradescantia virginiana L., Turgor of single cells was determined using the pressure probe. Sap of individual cells was collected with the probe for measuring the freezing-point depression in a nanoliter osmometer. Turgor pressure was by 0.2 to 0.4 MPa larger in mesophyll cells than in epidermal cells. A water-potential gradient, which was dependent on the rate of transpiration, was found between epidermis and mesophyll and between tip and base of the test leaf. Step changes of humidity or light resulted in changes of epidermal and mesophyll turgor (_p-epi, _p-mes) and could be correlated with the transpiration rate. Osmotic potential was not affected by a step change of humidity or light. For the humidity-step experiments, stomatal conductance (g) increased with increasing epidermal turgor.g/_p-epi appeared to be constant over a wide range of epidermal turgor pressures. In light-step experiments this type of response was not found and stomatal conductance could increase while epidermal turgor decreased.Symbols E transpiration - g leaf conductance - w leaf/air vapour concentration difference - -epi water potential of epidermal cells - -mes water potential of mesophyll cells - -xyl water potential of xylem - _p-epi turgor pressure of epidermal cells - _p-mes turgor pressure of mesophyll cells - _s-epi osmotic potential of epidermal cells - _s-mes osmotic potential of mesophyll cells     

Adrenergic and muscarinic receptor regulation and therapeutic implications in heart failure

In end-stage heart failure the expression of different myocardial regulatory proteins involved in the -adrenergic cAMP signalling pathway is altered. The downregulation of -adrenoceptors and their uncoupling from the effector as well as an increased expression of the inhibitory GTP-binding protein seem to be the most important alterations. Since catecholamine levels are elevated in these patients and since some alterations can be restored after treatment with -adrenoceptor antagonists it was hypothesized that excessive -adrenergic stimulation could be involved in these alterations.In this article the changes of -adrenergic receptors, GTP-binding proteins, sarcoplasmic reticulum Ca²⁺-ATPase and of phospholamban found in heart failure are addressed with its possible therapeutic implications.     

A model for neural representation of binocular disparity in striate cortex: distributed representation and veto mechanism

A model in striate cortex is proposed for a distributed neural representation of binocular disparity with a simple cell. In the model, disparity is represented by far, near and tuned inhibitory simple cells. However, the representation will be vetoed by model cells where disparity is excessively large. The veto mechanism consists of a neural network of the model cell which received output from simple cells and which interacts with neighbors. The mechanism is necessary, the model cell responds like a simple cell, and the network is physiologically plausible in the brain. Computer simulation on the neural network model with random dot stereography indicates reasonable performance.     

Differential Expression and Association of Calcium Channel Subunits in Development and Disease

Voltage-gated calcium channels (VDCC) are essential to neuronal maturation and differentiation. It is believed that important signaling information is encoded by VDCC-mediated calcium influx that has both spatial and temporal components. VDCC are multimeric complexes comprised of a pore-forming ₁ subunit and auxiliary and ₂/ subunits. Changes in the fractional contribution of distinct calcium conductances to the total calcium current have been noted in developing and differentiating neurons. These changes are anticipated to reflect the differential expression and localization of the pore-forming ₁ subunits. However, as in vitro studies have established that regulates the channel properties and targeting of ₁, attention has been directed toward the developmental expression and assembly of isoforms. Recently, changes in the component of the omega-conotoxin GVIA (CTX)-sensitive N-type VDCC have indicated differential assembly of _1B with in postnatal rat brain. In addition, unique properties of 4 have been noted with respect to its temporal pattern of expression and incorporation into N-type VDCC complexes. Therefore, the expression and assembly of specific ₁/ complexes may reflect an elaborate cellular strategy for regulating VDCC diversity. The importance of these developmental findings is bolstered by a recent study which identified mutations in the 4 as the molecular defect in the mutant epileptic mouse (lethargic; lh/lh). As 4 is normally expressed in both forebrain and cerebellum, one may consider the impact of the loss of 4 upon VDCC assembly and activity. The importance of the lb and 4 isoforms to calcium channel maturation and assembly is discussed.     

Interpretation of metameric architecture in dominant shrubs of the Chilean matorral

Summary The seasonal progression of phenophases in 21 shrub species of the Chilean matorral was analyzed. Five modules or basic units that are responsible for the aboveground architecture of the plants were characterized. These modules appear to be organized in seven different spatial arrangements. In drought-deciduous species a module type with an absolute short shoot with limited apical growth, leafy or spiny, predominated. In evergreen species long shoot and temporal leafy short shoot module types were more frequent. The spatial arrangement of morphologically different modules and the temporal sequence of their formation allow a dynamic interpretation of the modular architecture of the plants.     

Gene expression profiling during thymus ontogeny and its association with TCRVβ8.1-Dβ2.1 rearrangements of inbred mouse strains

The V(D)J recombination of TCR and in early developing T-cells is a highly modulated phenomenon initiated and completed by recombinase complex (RAG-1 and RAG-2), and regulated by other gene products such as interleukins. To further evaluate the association of several other gene products with the evolution of TCRV8.1 V(D)J rearrangements in vivo, the mRNA expression levels of seven interleukins, three cytokines, receptors TCRV8.1 and IL-2R, MHC-I/MHC-II, RAG-1/RAG-2 and retroviral superantigen MMTV(SW) were measured by RT-PCR during the fetal development of the thymus of three inbred mouse strains (Balb-c, C57Bl/6 and CBA/J). Clustering using the Tree View software, was used to organize these genes based on similarity of expression patterns. Each strain displayed a different expression profile during thymus ontogeny.During the late developmental stage the most evident association was the kinetics of MMTV(SW) retrovirus, IL-2R and IL-7 overexpression with reduction of TCRV8.1-D2.1 rearrangement in the thymus of CBA/J mice. These data suggest a susceptibility of this strain to expression of MMTV(SW) upon reduction of the rearranged TCRV8.1-D2.1 segment in developing thymocytes, with parallel IL-7 overexpression.     

Population of Aonidiella aurantii on citrus varieties in relation to their physical and chemical characteristics

Different varieties of citrus exhibit a great variation in their susceptibility to infestation by the red scale, Aonidiella aurantii. Among the thirteen varieties investigated, mandarin clemantine, santara and baladi, orange baladi and rough lemon are the most resistant; while lemon baladi, sour orange and grapefruit are the most susceptible. The susceptibility to infestation decreases with the increase of oil glands in the leaves and fruits of citrus. The total amount of nitrogen, phosphorus and carbohydrates in the leaves of different varieties shows no correlation with their susceptibility to infestation.

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Résumé Différentes variétés de Citrus montrent de grandes variations dans leur sensibilité aux attaques par Aonidiella aurantii. Parmi les 13 variétés étudiées, les plus résistantes sont: mandarine clémentine, mandarine baladi et rough lemon, tandis que lemon baladi; sour orange et pamplemousse sont les plus sensibles.La sensibilité aux infestations décroît proportionnellement avec l'accroissement du nombre des glandes à huiles essentielles sur les feuilles de citrus. La quantité totale d'azote, de phosphore et d'hydrates de carbone dans les feuilles des différentes variétés ne montre aucune corrélation avec leur sensibilité aux infestations.

     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

The two β-oxidation sites in pea cotyledons

Two sites for -oxidation of fatty acids in pea (Pisum sativum L.) cotyledons exist. One site is the microbody, the other the mitochondrion. Mitochondrial -oxidation of fatty acids is carnitine-dependent. The fatty acid permeates the membrane as palmitoylcarnitine which is formed from cytosolic-side palmitoyl-CoA by a carnitine palmitoyltransferase located on the exterior face of the inner mitochondrial membrane as a peripheral protein. A single-gated pore integral membrane translocator is proposed to exchange the palmitoylcarnitine for carnitine or acetylcarnitine across the membrane. An internal (matrix side) carnitine palmitoyltransferase then reforms palmitoyl-CoA which enters -oxidation and subsequently the tricarboxylic-acid cycle.     

Lag-phases in phytochrome-mediated enzyme synthesis (PAL)

Summary In experiments with the mustard seedling (Sinapis alba L.) it was confirmed that in the case of secondary irradiation induction of PAL by phytochrome is a very rapid process. The lag-phase after the onset of light is too brief to be detected. However, the data of other investigators, who found extended secondary lag-phases in their experimental material, can be imitated with the mustard seedling. We explain why these investigators were not able to eliminate the secondary lag-phase.PAL=Phenylalanine ammonia-lyase (EC.4.3.1.5).     

DNA variations in regenerated plants of pea (Pisum sativum L.)

Summary The aim of this study was to determine whether DNA variations could be detected in regenerated pea plants. Two different genotypes were analyzed by cytogenetic and molecular techniques: the Dolce Provenza cultivar and the 5075 experimental line. Dolce Provenza regenerated plants showed a reduction in DNA content, particularly at the level of unique sequences and ribosomal genes. Moreover, regeneration was associated with an increase in DNA methylation of both internal and external cytosines of the CCG sequence. On the other hand, the DNA content of the 5075 line remained stable after regeneration. DNA reduction was found only in 5075 plants regenerated from callus cultures maintained for long incubation periods (about a year). The DNA variations observed are discussed both in relation to the genotype source and the role of tissue-culture stress.     

Transmission of plastids by pollen in Antirrhinum majus

Summary Up to now Antirrhinum was classified as a typical example for a uniparentalmaternal inheritance of the plastids. However, the findings reported here prove that also the male gametophyte of Antirrhinum may occasionally transmit plastids into the egg. This conclusion is based on genetic experiments involving a form of the plastom mutant prasinizans which is described as gelbgrüne prasinizans. In contrast to all other plastid mutations known in Antirrhinum majus this mutant originated in Sippe 50 is completely viable. In plants containing plastids of this mutant type only, the mutant character is manifested during early growth stages. Cotyledons and first foliage leaves which are initially white or white yellow, slowly turn green and become indistinguishable from normal Sippe 50. Reciprocal crosses of green Sippe 50 with gelbgrüne prasinizans gave few variegated descendants; the others were exclusively plants identical with the maternal parent as far as leaf colour is concerned (Table). The variegated individuals cannot be gene mutants since selfing and crossing experiments showed non-mendelian inheritance. Furthermore it could be ruled out that in the cross Sippe 50 x gelbgrüne prasinizans the three variegated descendants represent spontaneous new plastom mutants because the pale tissue in these plants turned green in the same way as the paternal parent. Because of the typical greening of this mutant and since plastid mutations could be ruled out we have to conclude that plastids were transmitted by the pollen parent into the egg. There these plastids multiplied together with the maternal plastids giving rise to the chimeras after sorting-out of the two plastid types. This interpretation is supported by the observation of mixed cells in tissues where the leaf variegation is finely mosaiced. The results were possible only because the plastids of the pollen parent can be unequivocally recognised.     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

Secondary structural changes in the intact and the disulfide bridges cleaved beta-lactoglobulin A and B in solutions of urea, guanidine hydrochloride, and sodium dodecyl sulfate

The relative proportions of -helix, -sheet, and unordered form in -lactoglobulin A and B were examined in solutions of urea, guanidine, and sodium dodecyl sulfate (SDS). In the curve-fitting method of circular dichroism (CD) spectra, the reference spectra of the corresponding structures determined by Chen et al. (1974) were modified essentially according to the secondary structure of -lactoglobulin B predicted by Creamer et al. (1983), i.e., that the protein has 17% -helix and 41% -sheet. The two variants showed no appreciable difference in structural changes. The reduction of disulfide bridges in the proteins increased -sheet up to 48% but did not affect the -helical proportion. The -helical proportions of nonreduced -lactoglobulin A and B were not affected below 2 M guanidine or below 3 M urea, but those of the reduced proteins began to decrease in much lower concentrations of these denaturants. By contrast, the -helical proportions of the nonreduced and reduced proteins increased to 40–44% in SDS. The -sheet proportions of both nonreduced and reduced proteins, which remained unaffected even in 6 M guanidine and 9 M urea, decreased to 24–25% in SDS.     

Characterization of gangliosides from Ehrlich ascites tumour cells and their variants

Differences in the nature of the gangliosides present in two types of Ehrlich ascites tumour (EAT) cells, the adherent and non-adherent EAT cells, were studied. Gangliosides were isolated by DEAE Sephadex column chromatography and analysed by high-performance thin-layer chromatography (HPTLC). The non-adherent EAT (na-EAT) cells which grow in the peritoneal cavity of mice were selected for growth on basement membrane and tissue culture plastic to give the adherent EAT (a-EAT) cells. na-EAT cells contained 1.57 nmol lipid-bound sialic acid per mg protein and at least 12 different gangliosides, including major gangliosides such as GM3, GM2, GM1, GD3, GD1a and GT1b. On the other hand, the ganglioside pattern of a-EAT cells differed significantly from that of na-EAT cells, both quantitatively and qualitatively. The content of lipid-bound sialic acid in a-EAT cells was only 0.24 nmol per mg of protein. The gangliosides in a-EAT cells were characterized as GD1a and trisialogangliosides and, significantly, a-EAT cells did not contain monosialogangliosides. Neutral glycolipids were isolated from both cell lines and their patterns were compared. In contrast to the gangliosides pattern, their neutral glycolipid patterns were similar. Glucosylceramide and lactosylceramide were the major components in both types of cells. In addition to na- and a-EAT cells, a-EAT cells were passaged in mice by intraperitoneal injection, giving rise to a third variant (c/m EAT cells). We analysed the gangliosides in c/m EAT cells to determine whether there was a change in the ganglioside pattern found in na-EAT cells. After repeated passage of c/m EAT cells in mice, the pattern of gangliosides shifted to that of na-EAT cells. Alterations of ganglioside composition may be associated with the growth environment of the murine peritoneal cavity; alternatively, a selection process may have occurred.Abbreviations EAT cells Ehrlich ascites tumour cells - na-EAT cells non-adherent EAT cells - a-EAT cells adherent EAT cells - c/m EAT cells cultured a-EAT cells passaged in mice - HPTLC high-performance thin-layer chromatography - PBS 10 mM phosphate-buffered saline, pH 7.2, containing 0.15 M NaCl - EDTA ethylene-diaminetetraacetic acid - TFA trifluoroacetic acid - TG thioglycollate - Cer ceramide (N-fatty acyl sphingosine) - GM3 NeuAc2-3Gal1-4Glc-Cer - GM2 GalNAc1-4(NeuAc2-3)Gal1-4Glc-Cer - GM1a Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc-Cer - GD3 NeuAc2-8NeuAc2-3Gal1-4Glc-Cer - GD1a NeuAc2-3Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc-Cer - GT1b NeuAc2-3Gal1-3GalNAc1-4(NeuAc2-8NeuAc2-3)Gal1-4Glc-Cer - LacCer Gal1-4Glc-Cer - Gb3 Gal1-4Gal1-4Glc-Cer - Gb4 GalNAc1-4Gal1-4Gal1-4Glc-Cer This paper is dedicated to my esteemed colleague, Sen-itiroh Hakomori on the occasion of his 65th birthday.