Evidence of regional differences in the lectin histochemistry along the ductus epididymis of the lizard,Podarcis sicula Raf

The regional difference in the carbohydrate components of the ductus epididymis epithelium of a lizard was delineated by means of 13 lectins. Basal cells expressed only N-acetylglucosamine (GlcNAc). Throughout the ductus, the secretory cells showed oligosaccharides with terminal N-acetylneuraminic acid (Neu5Ac)(2,6)galactose (Gal)/N-acetylgalactosamine (GalNAc) and internal mannose (Man) and/or glucose (Glc) in the whole cytoplasm, oligosaccharides terminating in Neu5Ac(2,6)Gal(1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, GalNAc, GlcNAc, and fucose (Fuc) in the supra-nuclear zone, and also glycans terminating in Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal(1,3)GalNAc, Gal (1,4)GlcNAc on the luminal surface. In the caput and corpus regions, the supra-nuclear cytoplasm was characterized by terminal Gal(1,4)GlcNAc and GalNAc, the luminal surface by GalNAc and Gal. The Golgi zone, showing oligosaccharides with terminal Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal (1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, and internal GlcNAc, expressed terminal Gal (1,4)GlcNAc and GalNAc in the caput, and terminal GalNAc in the corpus. The granules showed all the investigated carbohydrates in their peripheral zone except terminal GalNAc and Fuc, whereas internal Man/Glc and terminal Gal were expressed in the central core, and Fuc throughout the ductus, terminal GlcNAc in the caput and corpus, and terminal GalNAc only in the corpus.     

Core substructure in Mastigocladus laminosus phycobilisomes

Three allophycocyanin complexes were separated by gel electrophoresis, isoelectric focusing and ion exchange chromatography from a low molecular fraction (M_r 100–150000) of partially dissociated phycobilisomes of Mastigocladus laminosus: A. (^APAP); B. (^*AP₂ ^AP₂ ^AP*AP) · L _C ¹⁰ ; and C. (^*APAPBAP₂ ^AP*AP) · L _C ¹⁰ . According to their fluorescence emission maximum at room temperature the complexes A., B. and C. are designated AP 660, AP 664 and AP 680. The different subunits of the AP complexes have apparent molecular weights of M_r 18500 ^*AP, 18200 ^APB, 18000 ^AP, 17000 ^AP and 16500 ^*AP. This hitherto unrecognized microheterogeneity within the AP subunits of complexes B. and C. of Mastigocladus laminosus phycobilisomes could also be demonstrated and confirmed with the two phycocyanin complexes PC 642 and PC 646. PC 642 is characterized by a L _R ¹¹ linker polypeptide.Abbreviations AP allophycocyanin - PC phycocyanin - PEC phycoerythrocyanin - PE phycoerythrin - PAGE polyacrylamide gel electrophoresis - IEF isoelectric focusing - pI isoelectric point - M_r apparent molecular weight - TMED tetramethylethylenediamine - APS ammonium persulphate - SDS sodium dodecylsulphate - O.D. optical density A preliminary account of this work has been presented at the Embo Workshop on Oxygenic and Anoxygenic Electron Transport Systems in Cyanobacteria (Blue-green Algae) in Cape Sounion, Greece, 20–25 September 1987     

Physicochemical characterization of β-crystallins from bovine lenses: Hydrodynamic and aggregation properties

A detailed investigation of the hydrodynamic and aggregation behaviors has been made on the -crystallins of bovine lens. Results from this study indicated that H (high-molecular-weight -crystallin) and L (low-molecular-weight -crystallin) exhibited considerable heterogeneity in their native structures and subunit polypeptides. Low-speed sedimentation equilibrium showed a heterogeneous paucidisperse system in each -crystallin fraction. Viscosity and circular dichroism studies pointed to a compact and globular shape and the presence of -sheet and -turns in these crystallins. Dissociation of H by urea and guanidinium HCl followed by reassociation during gel-filtration chromatography produced an elution pattern with two fractions corresponding to L crystallin and high-molecular-weight aggregates without the formation of native H. By contrast, under similar treatment, about 60% L reassociated into the correct native structure and the rest into high-molecular-weight fractions. Amino acid analyses of H and L and their corresponding subunit polypeptides demonstrated the close similarity of these crystallins. Trace element analyses indicated that both Ca and Mg are present in H and L crystallins and may be involved in maintaining the native quarternary structures of these proteins.     

Effect of organic and inorganic fertigation on yields, δ15N values, and δ13C values of tomato (Lycopersicon esculentum Mill. cv. Saturn)

We examined the effects of fertilizer application, especially the effects of fertigation and types of fertilizer (inorganic and organic) on yields and ¹⁵N and ¹³C values of tomato (Lycopersicon esculentum Mill. cv. Saturn). Fertigation is a method in which an appropriate diluted liquid fertilizer is applied to the plants each time they are drip-irrigated. We developed a method of organic fertigation using corn steep liquor (CSL) as the liquid fertilizer, because it is an industrial byproduct of cornstarch manufacture and can be used very effectively. We compared fruit yield, mineral content, ¹⁵N value, and ¹³C value of tomatoes grown under three different fertilizer treatments, basal dressing: basal dressing with granular chemical fertilizer; inorganic fertigation: fertigation with liquid chemical fertilizer; and organic fertigation: fertigaion with CSL. Mineral contents of tomatoes grown with basal dressing were generally lower than those grown under either fertigation treatment. These results indicated that yields and mineral contents were influenced more by the method of fertilizer application than by whether the fertilizers were inorganic or organic. There were, however, significant differences in the ¹⁵N values of tomato fruits grown under different types of fertilizer applications, especially between inorganic and organic fertilizers. The ¹⁵N value of the chemical fertilizer used for basal dressing was 0.81 ± 0.45{}, that of the chemical fertilizer for fertigation was 0.00 ± 0.04{}, and that of CSL was 8.50 ± 0.71{}. The ¹⁵N values of the soils reflected the ¹⁵N values of the fertilizers. Moreover, the ¹⁵N values of the fruits corresponded to the ¹⁵N values of the applied fertilizers. The ¹⁵N values were 3.18 ± 1.34{} in the fruits grown with a basal dressing of chemical fertilizer, 0.30 ± 0.61 in those grown under inorganic fertigation, and 7.09 ± 0.68 in those grown under organic fertigation. On the other hand, although the ¹³C values in the soil also reflected the ¹³C values of the applied fertilizers, there was no significant difference in the ¹³C values of fruits among the different treatments. In conclusion, because the ¹⁵N values of fertilizers correlated well with those of the fruits, it may be possible to use ¹⁵N values as an indicator of organic products.     

Induction of 3'-O-beta-D-ribofuranosyl adenosine during compatible, but not during incompatible, interactions of Arabidopsis thaliana or Lycopersicon esculentum with Pseudomonas syringae pathovar tomato

All hitherto identified aromatic compounds accumulating in leaves of Arabidopsis thaliana (L.) Heynh. upon infection with virulent or avirulent strains of Pseudomonas syringae pathovar tomato (Pst) were indolic metabolites. We now report the strong accumulation of a novel type of natural product, 3-O--d-ribofuranosyl adenosine (3RA), exclusively during compatible interactions. In contrast to the various indolic metabolites, 3RA was undetectable in incompatible interactions of A. thaliana leaves with an avirulent Pst strain, as well as in uninfected control leaves. A similar, strong induction of 3RA was observed in compatible but, again, not in incompatible interactions of Pst with its natural host, Lycopersicon esculentum. The strength of the effect and its confinement to compatible interactions suggests that it may be applicable as a diagnostic tool.Abbreviations Pst Pseudomonas syringae pathovar tomato - 3RA 3-O--d-ribofuranosyl adenosine     

Behavior of organelles and their nucleoids in the shoot apical meristem during leaf development in Arabidopsis thaliana L.

The behavior of organelle nucleoids and cell nuclei was studied in the shoot apical meristem and developing first foliage leaves of Arabidopsis thaliana. Samples were embedded in Technovit 7100 resin, cut into thin sections and stained with 4-6-diamidino-2-phenylindole to observe DNA. Fluorimetry was performed using a video-intensified microscope photon-counting system. The DNA content of individual mitochondria was more than 1 Mbp in the shoot apical meristem and the young leaf primordium, and decreased to approximately 170 kbp in the mature foliage leaf. In contrast, the DNA content of individual plastids was low in the shoot apical meristem and increased until day 7 after sowing. Application of 5-bromo-2-deoxyuridine, an analogue of thymidine, was usesd to investigate DNA synthesis in situ. The activities of DNA synthesis in the mitochondria and plastids changed according to the stage of development. Mitochondrial DNA was actively synthesized in the shoot apical meristem and young leaf primordia. This strongly suggests that the amount of mitochondrial DNA per mitochondrion, which has been synthesized in the shoot apical meristem and young leaf primordium, is gradually reduced due to continual divisions of the mitochondria during low levels of mitochondrial DNA synthesis. Synthesis of DNA in the plastid became active in the leaf primordia following DNA synthesis in the mitochondria, and the small plastids were filled with large plastid nucleotids. This enlargement of the plastid nucleoids occurred before the synthesis of ribulose-1,5-bisphosphate carboxylase/oxygenase and the development of thylakoids.Abbreviations BrdU 5-bromo-2-deoxyuridine - DAPI 4-6-diamidino-2-phenylindole - DiOC₆a 3,3-dihexyloxacarbocyanine - mtDNA mitochondrial DNA - mt-nucleoid mitochondrial nucleoid - ptDNA plastid DNA - pt-nucleoid plastid nucleoid - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase This work was supported by grant No. 2553 to M.F. and Nos. 04454019, 03304005 and 06262204 to T.K. from the Ministry of Education, Science and Culture of Japan, and by a grant for a pioneering research project in biotechnology from the Ministry of Agriculture, Forestry and Fisheries of Japan.     

Action of nereistoxin on recombinant neuronal nicotinic acetylcholine receptors expressed in<Emphasis Type="Italic"> Xenopus laevis</Emphasis> oocytes

Nereistoxin (NTX), a natural neurotoxin from the salivary glands of the marine annelid worm Lumbriconereis heteropoda, is highly toxic to insects. Its synthetic analogue, Cartap, was the first commercial insecticide based on a natural product. We have used voltage-clamp electrophysiology to compare the actions of NTX on recombinant nicotinic acetylcholine receptors (nicotinic AChRs) expressed in Xenopus laevis oocytes following nuclear injection of cDNAs. The recombinant nicotinic AChRs investigated were chicken 7, chicken 42 and the Drosophila melanogaster/chicken hybrid receptors SAD/2 and ALS/2. No agonist action of NTX (0.1–100 M) was observed on chicken 7, chicken 42 and the Drosophila/chicken hybrid nicotinic AChRs. Currents elicited by ACh were reduced in amplitude by NTX in a dose-dependent manner. The toxin was slightly more potent on recombinant Drosophila/vertebrate hybrid receptors than on vertebrate homomeric (7) or heteromeric (42) nicotinic AChRs. Block by NTX of the chicken 7, chicken 42 and the SAD/2 and ALS/2 Drosophila/chicken hybrid receptors is in all cases non-competitive. Thus, the site of action on nicotinic AChRs of NTX, to which the insecticide Cartap is metabolised in insects, differs from that of the major nicotinic AChR-active insecticide, imidacloprid.     

Relationships among violaxanthin deepoxidation,thylakoid membrane conformation,and nonphotochemical chlorophyll fluorescence quenching in leaves of cotton (Gossypium hirsutum L.)

The kinetics and temperature dependencies of development and relaxation of light-induced absorbance changes caused by deepoxidation of violaxanthin to antheraxanthin and zeaxanthin (Z; peak at 506 nm) and by light scattering (S; peak around 540 nm) as well as of nonphotochemical quenching of chlorophyll fluorescence (NPQ) were followed in cotton leaves. Measurements were made in the absence and the presence of dithiothreitol (DTT), an inhibitor of violaxanthin deepoxidase. The amount of NPQ was calculated from the Stern-Volmer equation. A procedure was developed to correct gross AS (S_g) for absorbance changes around 540 nm that are due to a spectral overlap with Z. This protocol isolated the component which is caused by light-scattering changes alone (S_n). In control leaves, the kinetics and temperature dependence of the initial rate of rise in S_n that takes place upon illumination, closely matched that of Z. Application of DTT to leaves, containing little zeaxanthin or antheraxanthin, strongly inhibited both S_n and NPQ, but DTT had no inhibitory effect in leaves in which these xanthophylls had already been preformed, showing that the effect of DTT on A_n and NPQ results solely from the inhibition of violaxanthin deepoxidation. The rates and maximum extents of S_n and NPQ therefore depend on the amount of zeaxanthin (and/or antheraxanthin) present in the leaf. In contrast to the situation during induction, relaxation of Z upon darkening was much slower than the relaxation of S_n and NPQ. The relaxation of S_n and NPQ showed quantitatively similar kinetics and temperature dependencies (Q₁₀=2.4). These results are consistent with the following hypotheses: The increase in lumen-proton concentration resulting from thylakoid membrane energization causes deepoxidation of violaxanthin to antheraxanthin and zeaxanthin. The presence of these xanthophylls is not sufficient to cause S_n or NPQ but, together with an increased lumen-proton concentration, these xanthophylls cause a conformational change, reflected by S_n. The conformational change facilititates nonradiative energy dissipation, thereby causing NPQ. Membrane energization is prerequisite to conformational changes in the thylakoid membrane and resultant nonradiative energy dissipation but the capacity for such changes in intact leaves is quite limited unless zeaxanthin (and/or antheraxanthin) is present in the membrane. The sustained S_n and NPQ levels that remain after darkening may be attributable to a sustained high lumen-proton concentration.Abbreviations A antheraxanthin - DTT dithiothreitol - F, F_m chlorophyll fluorescence yield at actual, full closure of the PSII centers - NPQ nonphotochemical chlorophyll fluorescence quenching - PFD photon flux density - PSII photosystem II - V violaxanthin - Z zeaxanthin - S_n, Z spectral absorbance change caused by light-scattering, violaxanthin deepoxidation We thank Connie Shih for skillful assistance in growing the plants, and for conducting HPLC analyses. A Carnegie Institution Fellowship and a Feodor-Lynen-Fellowship by the Alexander von Humboldt-Foundation to W. B. is gratefully acknowledged. This work was supported in part by Grant No. 89-37-280-4902 of the Competitive Grants Program of the U.S. Department of Agriculture to O.B. This is C. I. W. — D. P. B. Publication No. 1094.     

Interaction among anion,cation and glucose transport proteins in the human red cell

Summary The time course of binding of the fluorescent stilbene anion exchange inhibitor, DBDS (4,4-dibenzamido-2,2-stilbene disulfonate), to band 3 can be measured by the stopped-flow method. We have previously used the reaction time constant, _DBDS, to obtain the kinetic constants for binding and, thus, to report on the conformational state of the band 3 binding site. To validate the method, we have now shown that the ID₅₀ (0.3±0.1 m) for H₂-DIDS (4,4-diisothiocyano-2,2-dihydrostilbene disulfonate) inhibition of _DBDS is virtually the same as the ID₅₀ (0.47±0.04 m) for H₂-DIDS inhibition of red cell Cl^– flux, thus relating _DBDS directly to band 3 anion exchange. The specific glucose transport inhibitor, cytochalasin B, causes significant changes in _DBDS, which can be reversed with intracellular, but not extracellular,d-glucose. ID₅₀ for cytochalasin B modulation of _DBDS is 0.1±0.2 m in good agreement withK _D =0.06±0.005 m for cytochalasin B binding to the glucose transport protein. These experiments suggest that the glucose transport protein is either adjacent to band 3, or linked to it through a mechanism, which can transmit conformational information. Ouabain (0.1 m), the specific inhibitor of red cell Na⁺,K⁺-ATPase, increases red cell Cl^– exchange flux in red cells by a factor of about two. This interaction indicates that the Na⁺,K⁺-ATPase, like the glucose transport protein, is either in contact with, or closely linked to, band 3. These results would be consistent with a transport proteincomplex, centered on band 3, and responsible for the entire transport process, not only the provision of metabolic energy, but also the actual carriage of the cations and anions themselves.     

The exudation of γ-glutamyl-alanine by root tips of pea plants

Summary The identification of a compound exuded by root tips of pea plants is described. This compound, in earlier reports designated as unknown X, appeared to be -glutamyl-alanine.     

Botanic gardens: Future challenges and responsibilities

In this introduction to the papers resulting from the Specimen to Habitat Management Conference hosted by the Royal Botanic Gardens, Kew, in September 1991. Current and future issues facing botanic gardens are outlined and responses outlined.     

Organogenesis and somatic embryogenesis in callus cultures ofRosa hybrida andRosa chinensis minima

Pre-incubation of somatic tissues of the cut rose Carefree Beauty and miniature roses Red Sunblaze and Baby Katie in 10, 100, or 200 M 2,4-D induced the development of highly rhizogenic callus. Upon transfer of rhizogenic callus to a regeneration medium containing 23 M TDZ and 3 M GA₃, a low frequency of shoot organogenesis (3.3%) and somatic embryogenesis (6.6%) was observed. Incubation of leaf and stem internodes in 11, 27, 54, 81, or 108 M NAA followed by transfer of explants to the regeneration medium resulted in up to a 25% increase in shoot organogenesis from callus-derived internodal explants of Red Sunblaze, but no somatic embryogenesis was observed. The influence of glucose versus sucrose in the regeneration medium on leaf explants of Carefree Beauty and Baby Katie pre-incubated in 100 M 2,4-D revealed a difference in genotypic response to shoot organogenesis and somatic embryogenesis. For Carefree Beauty, a concentration of 111 mM glucose induced higher frequencies of both organogenic (33%) and embryogenic calluses (25%) than either 59 mM or 117 mM sucrose. For Baby Katie, no significant difference was found for number of organogenic calluses induced on 59 mM sucrose and 111 mM glucose.Abbreviations ABA Abscisic acid - BA Benzyladenine - 2,4-D 2,4-Dichlorophenoxyacetic acid - GA₃ Gibberellic acid - IAA Indoleacetic acid - MS Murashige & Skoog (1962) - NAA -Naphthaleneacetic acid - TDZ Thidiazuron     

Genetic Distance in Housekeeping Genes Between <Emphasis Type="Italic">Plasmodium falciparum</Emphasis> and <Emphasis Type="Italic">Plasmodium reichenowi</Emphasis> and Within <Emphasis Type="Italic">P. falciparum</Emphasis>

The time to the most recent common ancestor of the extant populations of Plasmodium falciparum is controversial. The controversy primarily stems from the limited availability of sequences from Plasmodium reichenowi, a chimpanzee malaria parasite closely related to P. falciparum. Since the rate of nucleotide substitution differs in different loci and DNA regions, the estimation of genetic distance between P. falciparum and P. reichenowi should be performed using orthologous sequences that are evolving neutrally. Here, we obtained full-length sequences of two housekeeping genes, sarcoplasmic and endoplasmic reticulum Ca²⁺-ATPase (serca) and lactate dehydrogenase (ldh), from 11 isolates of P. falciparum and 1 isolate of P. reichenowi and estimate the interspecific genetic distance (divergence) between the two species and intraspecific genetic distance (polymorphism) within P. falciparum. Interspecific distance and intraspecific distance at synonymous sites of interspecies-conserved regions of serca and ldh were 0.0672±0.0088 and 0.0011±0.0007, respectively, using the Nei and Gojobori method. Based on the ratio of interspecific distance to intraspecific distance, the time to the most recent common ancestor of P. falciparum was estimated to be (8.30±5.40) × 10⁴ and (11.62±7.56) × 10⁴ years ago, assuming the divergence time of the two parasite species to be 5 and 7 million years ago, respectively.This article contains an online supplementary table.Reviewing Editor: Dr. Martin Kreitman     

Increasing infiltration and activation of CD8+ tumor-infiltrating lymphocytes after eliminating immune suppressive granulocyte/macrophage progenitor cells with low doses of interferon γ plus tumor necrosis factor α

By secreting granulocyte/macrophage colonystimulating factor (GM-CSF), metastatic Lewis lung carcinoma (LLC-LN7) tumors induce the appearance of myelopoiesis-associated immune-suppressor cells that resemble granulocytic-macrophage (GM) progenitor cells. The presence of these GM-suppressor cells in mice bearing LLC-LN7 tumors was associated with a reduced capacity of splenic T cells to proliferate in response to interleukin-2 (IL-2). Administration of low doses of 100 U interferon (IFN) plus 10 U tumor necrosis factor (TNF) to the tumor bearers, a combination treatment that we previously showed to diminish the presence of GM-suppressor cells synergistically, restored proliferative responsiveness of the splenic T cells to IL-2. These LLC-LN7-bearing mice were also examined for whether cells that phenotypically resemble GM-progenitor cells (ER-MP12⁺ cells) infiltrate the tumor mass. ER-MP12⁺ cells composed approximately 10% of the cells isolated from dissociated tumors of mice that had been treated with placebo or with either IFN or TNF alone, but IFN/TNF therapy markedly reduced the number of tumor-infiltrating ER-MP12⁺ suppressor cells. The IFN/TNF treatment to eliminate GM-suppressor cells and restore T cell responsiveness to IL-2 was next coupled with low dose IL-2 therapy (100 U twice daily). Addition of IL-2 to the treatment regimen did not significantly influence the effectiveness of the IFN/TNF treatment in eliminating GM-suppressor cells from the LLC-LN7 tumor mass. However, inclusion of IL-2 with the IFN/TNF treatment regimen enhanced the CD8⁺, but not the CD4⁺, cell content within the tumor, and diminished the number of metastatic lung nodules within the mice. When these tumors were excised, dissociated, and bulk-cultured with a low dose of IL-2, an increased level of cytotoxic T lymphocyte (CTL) activity was generated in the TIL cultures from mice that had received IFN/TNF plus IL-2 treatments. A lesser but detectable level of CTL activity was generated in TIL cultures from mice that were treated with only IFN/TNF, while no CTL activity was generated in tumor cultures from mice receiving only placebo or low-dose IL-2. These results suggest the effectiveness of IFN plus TNF therapy in restoring IL-2 responsiveness in mice bearing GM-suppressor cell-inducing tumors and at enhancing both the intratumoral CD8⁺ cell content and the generation of CTL activity in bulk cultures of these tumors.This study was supported by the Medical Research Service of the Department of Veterans Affairs, by grants CA-45080 and CA-48080 from the National Institutes of Health, and by the American Cancer Society, Illinois     

Distinct patterns of expression of the β-1,4-galactosyltransferases during testicular development in the mouse

Glycosylation is one of the most important post-translational modifications and it is clear that the single step of -1,4-galactosylation is performed by a family of -1,4-galactosyltransferases (4-GalTs) and that each member of this family may play a distinct role in different tissues and cells. In this study, we characterized the gene expression of six 4-GalTs in mouse testis and analyzed the changes of galactosylation of testis glycoproteins during postnatal development. Northern blot analysis revealed that 4-GalT-I and 4-GalT-IV were expressed mainly in newborn mouse testis and that the expression of 4-GalT-II increased markedly and persisted at the highest levels in adult mouse testis. The expression of 4-GalT-III and 4-GalT-V, however, remained relatively at low levels during mouse testicular development. In contrast, the expression of 4-GalT-VI was undetectable in mouse testis. The gene expression of 4-GalT-II in mouse testis was further analyzed by in situ hybridization due to its unique expression pattern. Strong hybridization signals were detected in the seminiferous tubules and the expression varied among the different stages of spermatogenic differentiation. The distinct gene expression patterns of 4-GalTs in mouse testis could affect the differential galactosylation of testis glycoproteins, as revealed by lectin histochemistry analysis.     

Glycosphingolipid expression in human skeletal and heart muscle assessed by immunostaining thin-layer chromatography

In this study the comparative TLC immunostaining investigation of neutral GSLs and gangliosides from human skeletal and heart muscle is described. A panel of specific polyclonal and monoclonal antibodies as well as the GM1-specific choleragenoid were used for the overlay assays, combined with preceding neuraminidase treatment of gangliosides on TLC plates. This approach proved homologies but also quantitative and qualitative differences in the expression of ganglio-, globo- and neolacto-series neutral GSLs and gangliosides in these two types of striated muscle tissue within the same species. The main neutral GSL in skeletal muscle was LacCer, followed by GbOse3Cer, GbOse4Cer, nLcOse4Cer and monohexosylceramide, whereas in heart muscle GbOse3Cer and GbOse4Cer were the predominant neutral GSLs beside small quantities of LacCer, nLcOse4Cer and monohexosylceramide. No ganglio-series neutral GSLs and no Forssman GSL were found in either muscle tissue. GM3(Neu5Ac) was the major ganglioside, comprising almost 70% in skeletal and about 50% in cardiac muscle total gangliosides. GM2 was found in skeletal muscle only, while GD3 and GM1b-type gangliosides (GM1b and GD1) were undetectable in both tissues. GM1a-core gangliosides (GM1, GD1a, GD1b and GT1b) showed somewhat quantitative differences in each muscle; lactosamine-containing IV3Neu5Ac-nLcOse4Cer was detected in both specimens. Neutral GSLs were identified in TLC runs corresponding to e.g. 0.1 g muscle wet weight (GbOse3Cer, GbOse4Cer), and gangliosides GM3 and GM2 were elucidated in runs which corresponded to 0.2 g muscle tissue. Only 0.02 g and 0.004 g wet weight aliquots were necessary for unequivocal identification of neolacto-type and GM1-core gangliosides, respectively. Muscle is known for the lowest GSL concentration from all vertebrate tissues studied so far. Using the overlay technique, reliable GSL composition could be revealed, even from small muscle probes on a sub-orcinol and sub-resorcinol detection level. Abbreviations: ATCC, American Type Culture Collection; GSL(s), glycosphingolipid(s); HPLC, high performance liquid chromatography; HPTLC, high performance thin layer chromatography; Neu5Ac, N-acetylneuraminic acid; Neu5Gc, N-glycolylneuraminic acid [78]; PBS, phosphate buffered saline. The designation of the following glycosphingolipids follows the IUPAC-IUB recommendations [79] and the ganglioside nomenclature system of Svennerholm [80]. Lactosylceramide or LacCer, Gal1-4Glc1-1Cer; gangliotriaosylceramide or GgOse3Cer, GalNAc1-4Gal1-4Glc1-1Cer; gangliotetraosylceramide or GgOse4Cer, Gal1-3GalNAc1-4Gal1-4Glc1-1Cer; globotriaosylceramide or GbOse3Cer, Gal1-4Gal1-4Glc1-1Cer; globoside or globotetraosylceramide or GbOse4Cer, GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; Fo or Forssman GSL, GalNAc1-3GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; paragloboside or lacto-N-neotetraosylceramide or nLcOse4Cer, Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; lacto-N-norhexaosylceramide or nLcOse6Cer, Gal1-4GlcNAc1-3Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; GM3, II3Neu5Ac-LacCer; GM2, II3Neu5Ac-GgOse3Cer; GM1 or GM1a, II3Neu5Ac-GgOse4Cer; GM1b, IV3Neu5Ac-GgOse4Cer; GD3, II3(Neu5Ac)2-LacCer; GD1a, IV3Neu5Ac,II3Neu5Ac-GgOse4Cer; GD1b, (II3Neu5Ac)2-GgOse4Cer; GD1, IV3Neu5Ac,III6Neu5Ac-GgOse4Cer; GT1b, IV3Neu5Ac,II3(Neu5Ac)2-GgOse4Cer; GQ1b, IV3(Neu5Ac)2, II3(Neu5Ac)2-GgOse4Cer.     

Prolongation of MGE 412 Transposition Induction after γ-Irradiation in an Isogenic Line of Drosophila melanogaster

The dose dependence of the rate of -induced transpositions and consequent dynamics of the MGE 412pattern after -irradiation were investigated in isogenic line 49 in generations F₁, F₁₂, F₁₄₀, and F₁₇₀. It was shown that the results on dose dependence of transpositions was very similar with the corresponding results of the classic works by Timofeeff-Ressovsky et al.(1935). It is suggested that the transcribed copies of retrotransposon 412cure -radiation-induced double-strand DNA breaks. The phenomenon of prolongation of MGE transposition induction during early generations after treatment was shown. In this period (F₁–F₁₂), the maximum transposition rate ( 2 × 10^–2events per MGE copy, per haploid genome, per generation) and the maximum number of heterozygous MGE copies were achieved. In the late generations (F₁₄₀–F₁₇₀), the reduced induction level ( 10^–3) was established. In the population of effective size N _e= 2000 individuals, this corresponds to the state when 1/4N _e, i.e., when the transposition flow prevails over the MGE copy loss by genetic drift. These data together with some indirect evidence argue for the hypothesis that the spontaneous transposition rate is proportional to the average number of heterozygous MGE copies per diploid genome.     

A general linear model for the genotypic covariance between relatives under assortative mating

A linear model for the genotypic covariance between relatives under assortative mating comprising the classical linear model and the model of selective assortative mating is proposed. The general conditions on the genetical and developmental mechanisms of quantitative characters, as well as on selection and the mating system, on which the model is based, are explicitly stated and discussed. A classification of different relationships is presented and it is shown that these conditions are sufficient to obtain the genotypic covariance between relatives only if the relationship is a combination of descendant-ancestor, full sib, Type 1 and Nth uncle-niece relationships. All the traditional relationships, i.e., those for which the covariances of the relatives have been obtained in the literature, fall into this category. These conditions also ensure that the regression of the individual's genotypic value on the genotypic value or phenotype of any of its ancestors is always linear.Paper No. 6619 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. This investigation was supported in part by NIH Research Grant No. GM 11546 from the National Institute of General Medical Sciences