The association of the human ε-globin gene with the nuclear matrix: a reconsideration

The association of the human -globin gene with the nuclear matrix was studied in erythroid and non-erythroid cell lines. Using a high salt method to prepare histone depleted nuclei we studied the association of variety of fragments covering a 7.8 kb region which contains the human -globin gene. We furthermore studied the association of a set of DNA fragments covering the 13 kb human G/A-globin gene domain, the 16 kb /-globin gene domain and the 10 kb -globin gene domain with the nuclear matrix of K562 and Raji cells. The results show that all fragments studied are easily released from the nuclear matrix, indicating no specific association.Summarizing our results we could say that a region starting 5.7 kb 5 to the human -globin gene and ending 4 kb 3 to the human -globin gene seems to contain no attachment sites with the nuclear matrix of both erythroid and non-erythroid cells.     

Some observations on the fine structure of the myotendinous junction in myotomal muscles of the tadpole tail

Summary Myotendinous junctions in the myotomal tail muscles of the tadpole of Rana rugosa were examined by electron microscopy. At the site of the myotendinous junction, the sarcolemma is covered on its sarcoplasmic aspect by the connecting filament layer and the attachment layer, and on the extracellular aspect by the intermediary layer and the external lamina, with associated collagen fibrils. The intermediary layer consists of filamentous structures which closely resemble microfibrils (Hanak and Böck, 1971), spine-like or thread-like profiles (Korneliussen, 1973) and intermediary layer (Nakao, 1975a, b) in the myotendinous junctions of other vertebrate skeletal muscles.Particularly interesting is the fact that all the coverings and linings of the sarcolemma, including the external lamina, are completely absent in the terminal segment of the finger-like sarcolemmal invagination characteristic of the myotendinous junction. Furthermore, special types of coupling between a sac of sarcoplasmic reticulum and a part of the sarcolemmal invagination are frequently observed. These couplings always occur along the region of the sarcolemma where the external lamina is absent. The couplings show features similar to those of the triad, such as SR feet , scalloped SR membranes and granular content of the SR sac, suggesting that they are analogous and functionally similar to the triad and other equivalent structures.     

Texturerkennung und Texturreproduktion

The recognition of textures involves multiple local filtering and subsequent averaging of the image to produce a feature space in which textures are represented as cluster centers. Results are presented for a two variate algorithm involving the features brightness and roughness. Both regular and random textures generated by program are used. The final result of classification is expressed in terms of the original textures: the computer paints what it has seen — and makes rather understandable errors at the borders between different textures.     

A cDNA encoding vacuolar type β-d-fructofuranosidase (Osβfruct3) of rice and its expression in Pichia pastoris

A vacuolar type -d-fructofuranosidase (Osfruct3) was cloned from etiolated rice seedlings cDNA library. It encodes an open reading frame of 688 residues. The deduced amino acid sequence had 58% identity to the vacuolar type -d-fructofuranosidase of maize (Ivr1). Osfruct3 exists as a single copy per genome. Northern analyses showed that Osfruct3 undergoes organ-specific expression and is involved in the adjustment of plant responses to environmental signals and metabolizable sugars. Osfruct3 was also heterologously expressed in Pichia pastoris. The recombinant proteins were confirmed to be a vacuolar type -d-fructofuranosidase.     

Recombinant human interferon γ exerts an anti-proliferative effect and modulates the expression of human leukocyte antigens A,B,C and DR in human urothelial cell lines

Summary In this study we have treated three malignant (TGrIII) and two pre-malignant (TGrII) urothelial cell lines with recombinant human interferon (rHu-INF). The malignant cells (HCV29-T112C1, Hu1703He and T24) were inhibited in growth by more than 50% after treatment with 100–1000 units of rHu-INF/ml for 4 days as compared to untreated controls. The growth of the pre-malignant cell lines (HCV29 and Hu609) was not influenced to the same extent in the presence of rHu-INF in the culture medium. Treatment with rHu-INF increased the expression of monomorphic human leukocyte antigens (HLA) A,B,C as well as ₂-microglobulin in all the cell lines tested, as demonstrated using a quantitative immunofluorescence assay. The tumourigenic cell lines increased their expression of HLA in a dose-dependent way, whereas treatment of the non-tumourigenic cells with higher concentrations of rHu-INF than 10 units/ml, did not increase the HLA-A,B,C expression further. None of the cell lines expressed HLA-DR unless treated with rHu-INF. No correlation between tumourigenicity and the dose of rHu-INF required for de novo induction of HLA-DR could be demonstrated. After removal of rHu-INF from the medium, the expression of HLA-DR gradually decreased in less than 14 days, indicating that the expression of HLA-DR is not constitutive but dependent upon the presence of rHu-INF. We conclude that human urothelial cells grown in vitro are sensitive to the anti-proliferative and major-histocompatibility-complex-modulating effects of rHu-INF, and that malignant urothelial cells are more sensitive than pre-malignant cells. Finally, our data indicate a possible role for rHu-INF in the management of human bladder cancer.     

Immunization of cross-bred cattle against Hyalomma anatolicum anatolicum by purified antigens

Extracts prepared from unfed larvae of Hyalomma anatolicum anatolicum were purified by immunoaffinity chromatography using anti-gut IgG as ligand. Affinity purified antigen (Aff-GHLAg) was used to immunize cross-bred (Bos taurus×B. indicus) calves of 6–7 months of age. Immunized calves rejected 70.6% larvae, 54.5% nymphs and 61.9% adults. No significant changes in the engorged weight of females was observed; however, significant decrease in the engorgement weight of larvae and nymphs was recorded. There was a significant decrease in the emerging nymphs (p<0.05) and adults (p<0.01) of the tick stages fed on immunized animals. SDS-PAGE analysis revealed three antigenic proteins of 100, 59.4 and 37kDa responsible for induction of resistance in the host.     

Differential desensitization properties of rat neuronal nicotinic acetylcholine receptor subunit combinations expressed inXenopus laevis oocytes

Summary 1. Chronic administration of nicotine up-regulates mammalian neuronal nicotinic acetylcholine receptors (nAChRs). A key hypothesis that explains up-regulation assumes that nicotine induces desensitization of receptor function. This is correlated with behaviorally expressed tolerance to the drug.2. The present experiments were conducted to: (a) obtain information on the nicotine-induced desensitization of neuronal nAChR function, a less understood phenomenon as compared to that of the muscle and electric fish receptor counterparts; (b) test the hypothesis that different receptor subunit combinations exhibit distinct desensitization patterns.3.Xenopus laevis oocytes were injected with mRNAs encoding rat receptor subunits2,3, or4 in pairwise combination with the2 subunit. The responses to various concentrations of acetylcholine (ACh) or nicotine were analyzed by the two electrode voltage clamp technique.4. Concentration-effect curves showed that nicotine was more potent than ACh for all the receptor subunit combinations tested. Only the42 combination exhibited a depression of the maximum effect at concentrations higher than 20µM nicotine.5. After a single nicotine pulse, receptor desensitization (calculated as a single exponential decay) was significantly slower for42 than for either32 or22.6. Concentrations of nicotine that attained a near maximum effect were applied, washed, and re-applied in four minute cycles. The responses were calculated as percentages of the current evoked by the initial application. Following 16 minutes of this protocol, the42 combination showed a greater reduction of the original response as compared to the22 and32 subunit combinations. Taking points 5 and 6 together, these experiments suggest that the42 receptor subtype desensitizes at a slower rate and remains longer in the desensitized state.7. Because42 is the main receptor subunit combination within the brain and is up-regulated by nicotine, our data may be important for understanding the molecular basis of tolerance to this drug.     

Histochemical evidence for granulosa steroids in follicle maturation in the African catfish,Clarias lazera

Summary The effects of carp pituitary suspension (CPS) and 11-desoxycorticosterone-acetate (DOCA) on 3-hydroxysteroid dehydrogenase (3-HSD) and glucose-6-phosphate dehydrogenase (G6PD) activity in the ovary of Clarias lazera are described. Strong 3-HSD and G6PD activities are localized in the stroma, of both control and treated fish. A single CPS injection stimulates 3-HSD activity in the granulosa of postvitellogenic, maturing and postovulatory follicles, but DOCA has no such effect on the postvitellogenic and maturing follicles, and only stimulates a weak response in the postovulatory ones.     

β-Alanine Release from the Adult and Developing Hippocampus Is Enhanced by Ionotropic Glutamate Receptor Agonists and Cell-Damaging Conditions

The release of the inhibitory amino acid -alanine was investigated in hippocampal slices from adult (3-month-old) and developing (7-day-old) mice, using a superfusion system. The release was enhanced by -alanine itself and the structural analogs taurine and -aminobutyrate. It was dependent on Na⁺, but independent of Ca²⁺ in both mature and immature hippocampus, being thus mostly mediated by uptake carriers operating in an outward direction. The release was potentiated in the developing mice, but not affected in the adults, by the ionotropic glutamate receptor agonists N-methyl-D-aspartate, kainate, 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and tetrazolylglycine in a receptor-mediated manner. Cell-damaging conditions, including hypoxia, hypoglycemia, ischemia, oxidative stress and the presence of free radicals, greatly enhanced -alanine release at both ages, but more markedly in the adults. The great amounts of -alanine, together with the inhibitory amino acids taurine and -aminobutyrate, released simultaneously with the excitatory amino acids in the hippocampus may constitute an important protective mechanism against excitotoxicity, which leads to neuronal death.     

β-Globin gene polymorphism in Saudis — triple Hpa I fragments

Summary In an attempt to investigate -globin gene polymorphism in the Saudi population, DNA samples were analysed using restriction endonucleases, Mst II and Hpa I. Both ^A and ^S genes showed extensive polymorphism and were found to be linked to 13.0 kb, 7.6 kb, 7.0 kb, and 5.6 kb Hpa I fragments. Three DNA samples out of a total of 436 analysed, had -globin gene linked to three Hpa I fragments of the sizes 13.0 kb, 7.6 kb, and 5.6 kb. In this paper we present our findings and discuss the possibility of multiple -globin loci.     

Evolution of phosphagen kinase VII. Isolation of glycocyamine kinase from the polychaete Neanthes diversicolor and the cDNA-derived amino acid sequences of alpha and beta chains

Glycocyamine kinase (GK) was isolated from the marine polychaete Neanthes diversicolor by gel filtration, DEAE-cellulose chromatography, butyl-Toyopearl hydrophobic chromatography, and chromatofocusing. The GK was eluted as a single peak on the latter three chromatographies, and the molecular mass for the native GK was estimated to be about 80 kDa. The SDS–PAGE showed that the isolated GK consists of two distinct subunits in equal proportion, and chains, with molecular masses of 42.2 and 43.8 kDa, respectively. The present results suggest that the Neanthes GK has a heterodimeric structure. The cDNAs for and chains of Neanthes GK were amplified by PCR and their cDNA-derived amino acid sequences were determined. The and chains are composed of 374 and 390 amino acids, and the molecular masses were calculated to be 42,392 and 43,966 Da, respectively, in good agreement with the apparent masses on SDS–PAGE. The chain has a characteristic N-terminal extension of 15 amino acids, and all of the sequence differences between and chains were restricted in the N-terminal region of 50 residues. The overall sequence identity was 92%. The occurrence of heterodimeric nature in Neanthes GK is of great interest from the evolutionary point of view, because the heterodimeric structure is only known for creatine kinase MB-isozyme specific for mammalian heart muscle among phosphagen kinases.     

Voltage-gated cation conductance channel from fragmented sarcoplasmic reticulum: Steady-state electrical properties

Summary The interaction of fragmented sarcoplasmic reticulum (SR) with an artificial planar phospholipid membrane under conditions known to induce fusion of phospholipid vesicles raises the conductance of the planar bilayer by several orders of magnitude. Measurements of steady-state electrical properties of bilayers thus modified by SR show that two types of conductance pathways are present. One is a voltage-independent pathway which may be somewhat anion-selective. The other is a voltagegated ionophore showing selectivity to small monovalent cations. This latter ionophore is fully oriented within the artificial bilayer and is inhibited asymmetrically by divalent cations. It is also inhibited below pH 6. The ionophore displays single-channel conductance fluctuations between two states, open and closed, with an open-state conductance of 1.4×10^–10 mho in 0.1m K⁺. The physiological function of this ionophore is unknown.     

Identification of hybrids betweenQuercus petraea andQ. robur (Fagaceae): Results obtained with RAPD markers confirm allozyme studies based on theGot-2 locus

RAPDs were employed as genetic markers to detect interspecific hybridization between the closely related oak speciesQuercus robur andQ. petraea. Fourteen primers were used in order to check the genetic status (pure or hybrid) of individuals classified morphologically. Among the 147 PCR fragments obtained 11 appear to be species-specific. In the phenotypically intermediate individuals different combinations of these species-specific bands were obtained. The patterns in these putative hybrids were not additive, which may be either the result of repeated backcrossing and introgression between the two species or of heterozygosity within the parental species. The results of the RAPD study are consistent with morphological analyses and allozyme data obtained for theGot-2 locus. Thus the RAPD markers used in this study may provide a powerful genetic tool for the identification of hybrids and the discrimination between the two pure species.     

Below-ground biomass in healthy and impaired salt marshes

Twelve salt marshes in south Louisiana (USA) were classified as either impaired or healthy before a summer sample collection of above- and below-ground biomass and determination of sediment accretion rates. The above-ground biomass of plant tissues was the same at both impaired and healthy salt marshes and was not a good predictor of marsh health. However, below-ground root biomass in the upper 30cm was much lower in the impaired marshes compared to the healthy marshes. Compromises to root production apparently occur before there is an obvious consequence to the above-ground biomass, which may quickly collapse before remedial action can be taken. The subsequent change in vertical position of the marsh surface may be equivalent to many years of accretion, and be irreversible within decades without considerable effort. These results are consistent with the hypothesis that it is the plants below-ground accumulation of organic matter, not inorganic matter that governs the maintenance of salt marsh ecosystem in the vertical plane. Reversing the precursor conditions leading to marsh stress before the collapse of the above-ground biomass occurs is therefore a prudent management objective and could be easier than restoration.     

Binding of Amyloid Beta-Protein to Intracellular Brain Proteins in Rat and Human

Amyloid beta-protein (A), in its soluble form, is known to bind several circulatory proteins such as apolipoprotein (apo) E, apo J and transthyretin. However, the binding of A to intracellular proteins has not been studied. We have developed an overlay assay to study A binding to intracellular brain proteins. The supernatants from both rat and human brains were found to contain several proteins that bind to A 1–40 and A 1–42. No major difference was observed in the A binding-proteins from brain supernatants of patients with Alzheimer's disease and normal age-matched controls. Binding studies using shorter amyloid beta-peptides and competitive overlay assays showed that the binding site of A to brain proteins resides between 12–28 amino acid sequence of A. The presence of several intracellular A-binding (AB) proteins suggests that these proteins may either protect A from its fibrillization or alternatively promote A polymerization. Identification of these proteins and their binding affinities for A are needed to assess their potential role in the pathogenesis of Alzheimer's disease.     

Ultrastructure of paraspermatozoa,euspermatozoa and eusperm-like spermatozoa ofObtortio cf.fulva (Prosobranchia: Cerithiacea)

The cerithiaceanObtortio cf.fulva produces three distinct types of spermatozoa: (1) paraspermatozoa, (2) euspermatozoa and (3) eusperm-like spermatozoa. Like most mesogastropods, euspermatozoa ofObtortio are composed of a conical acrosome, short posteriorly invaginated nucleus, elongate midpiece and glycogen piece, and short terminal region. The midpiece, however, is distinctly cerithiacean in structure and is composed of four non-helical midpiece elements. Eusperm-like spermatozoa closely resemble euspermatozoa, but have a very short nucleus only one half to one third the length of the euspermatozoon nucleus. Paraspermatozoa of this species are composed of (1) head (mosaic sheath of dense blocks enveloping multiple axonemes which attach anteriorly to a long apical structure), (2) midpiece (multiple axonemes interspersed with elongate mitochondria), and (3) multiple tail tuft (axonemes each ensheathed by glycogen granules). The possible role of eusperm-like spermatozoa is briefly discussed together with the taxonomic implications of the structure of the three sperm types.     

Plant and insect diversity along a pollution gradient: understanding species richness across trophic levels

We analysed species richness of plants and true bugs (Insecta, Heteroptera) along a pollution gradient in Scots pine stands in Central Germany. As a consequence of particulate deposition, pH-values of soils increased in the vicinity of the emission source. Therefore, emission increased productivity. Species richness of plants increased with decreasing distance from emission source, and thus with increasing productivity. Similarly, species richness of herbivorous Heteroptera increased with decreasing distance from emission source, whereas, surprisingly, abundance decreased. The proportion of specialised herbivorous bug species is largest in the vicinity of the emission source. Thus, the diversity pattern of herbivores may be explained by the specialisation hypothesis and not the consumer rarity hypothesis. Species richness and abundance of carnivorous Heteroptera showed no significant trend along the gradient. Overall our data favour the bottom-up control of species diversity in the analysed system.     

Degradation of Soluble Amyloid β-Peptides 1–40, 1–42, and the Dutch Variant 1–40Q by Insulin Degrading Enzyme from Alzheimer Disease and Control Brains

Insulin degrading enzyme (IDE) is a metalloprotease that has been involved in amyloid peptide (A) degradation in the brain. We analyzed the ability of human brain soluble fraction to degrade A analogs 1–40, 1–42 and the Dutch variant 1–40Q at physiological concentrations (1 nM). The rate of synthetic ¹²⁵I-A degradation was similar among the A analogs, as demonstrated by trichloroacetic acid precipitation and SDS-PAGE. A 110 kDa protein, corresponding to the molecular mass of IDE, was affinity labeled with either ¹²⁵I-insulin, ¹²⁵I-A 1–40 or ¹²⁵I-A 1–42 and both A degradation and cross-linking were specifically inhibited by an excess of each peptide. Sensitivity to inhibitors was consistent with the reported inhibitor profile of IDE. Taken together, these results suggested that the degradation of A analogs was due to IDE or a closely related protease. The apparent Km, as determined using partially purified IDE from rat liver, were 2.2 ± 0.4, 2.0 ± 0.1 and 2.3 ± 0.3 M for A 1–40, A 1–42 and A 1–40Q, respectively. Comparison of IDE activity from seven AD brain cytosolic fractions and six age-matched controls revealed a significant decrease in A degrading activity in the first group, supporting the hypothesis that a reduced IDE activity may contribute to A accumulation in the brain.     

Ultrastructure of the oocyte and embryo of the calcified sponge,Petrobiona massiliana (Porifera,Calcarea)

Summary In the spongePetrobiona massiliana, a Calcarea related to pharetronid fossils, the oocyte and the embryo both receive an unusual amount of maternal nurse cells. Yolk granules are large and display a lamellar structure throughout the entire growth period, which allows them to be used as markers of the oocyte reserves. The cruciform cells (cellules en croix) of the embryo appear to degenerate at an early stage. These features are compared to those found in other Calcarea.     

Methodological problems in evolutionary biology VIII. Biology and culture

Biology cannot accommodate all aspects of culture. Aspects of culture that a biological approach can take into account can be covered by the biological categories of phenotype and environment. There is no need to treat culture as a separate category. Attempts to elaborate biological explanations of cultural variation will meet with success only if biologists expand theories of development, and integrate them in evolutionary biology. The alternative — elaborating the idea of so-called cultural inheritance — makes little sense from a biological point of view.