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The ultrastructure of autofluorescent, PAS-positive lipofuscin in Purkinje, granule, Golgi epithelial, basket and stellate, microglial and perivascular cells in the cerebellar cortex of senescent rats is described. The membrane- bounded pigment is composed ofthree elements: 1) electron-lucent homogeneaus droplets, 2) a granular matrix and 3) intensely osmiophilic patches. The proportians ofthese three components vary between cell types and one can grossly differentiate a neuronal and a gliallipofuscin. The lipofuscin granules of stellate and perivscular cells are different from lipofuscin of other cerebellar neurons and glia. lt can be concluded from these morphological observations that each cerebellar cell type has its distinct lipofuscin.
Jahresbericht 1978
(1979)
No abstract available
Sila-difenidol (6b), a sila-analogue of the drug difenidol (6a), was synthesized according to Scheme 1. 6b and its new precursors 3 and 5 were characterized by their physical and chemical properties, and their structures confirmed by elementary analyses, 1H NMR and mass spectroscopy. 6 b crystallizes orthorhombic \(P2_12_12_1\) with a = 11.523(1), b = 14.366(4), c = 11.450(1) Å, Z = 4, \(D_{ber} = 1.14 gcm^{-3}\). The structure was refined to R = 0.050 for 1897 reflexions. A strong nearly linear intramolecular O-H···N hydrogen bond of 2.685 Å is observed. The anticholinergic, histaminolytic and musculotropic spasmolytic activities of 6 a and 6 b are reported.
The desert isopod, Hemilepistus reaumuri, extremely common in the arid regions of North Africa and Asia Minor, depends upon the burrows it itself digs for survival during the hotter parts of the year. The dig-ging of new burrows is limited by chmatic conditions to a short period during the spring. Burrows must be constantly defendet - especially against roving eonspecifics. The decisive problem of a connnuous burrow defense is solved through cooperative behavior: the adult woodlice form monogamous pairs whose partners recognize one another individually. Here, questions on the binding of partners, especially the problem of the binding of male to female will be treated upon, along with questions on the evolution of monogamy, wherein the purely maternal families of Porcellio species will be taken as models for intermediäre stages. At first, males olHemilepistus are not permitted to copulate at all; later, for a relatively long period, they are only permitted incomplete copulations, the females alone have control over the partunal ecdysis; they alone determine the moment of final copulations. Under the thermal conditions prevalent during the season of pair formation, a female irreversibly induces a parturial ecdysis only when it has spent a minimum of sev-eral days in her own burrow with a specific male. At higher average temperatures, the number of females which undergo parturial ecdyses without these preconditions increases sharply. Males cannot greatly lnrlu-ence the willingness of females to reproduce with the investment they make in the digging of burrows; the factors deciding this are the male's presence and its role as guard. The first condition necessary for the genesis of monogamy might have been the evolution of a stncüy lo-cation-dependent copulatory behavior, which guaranteed the male exclusive mating pnveliges with the female whose location - the burrow - he acheived control of. A male must, under these conditions, serve guard duty in his own interest, and defend the burrow against competitors (Cf or 2) seeking an already-dug burrow. The decisive advantage for the female in the beginning of the development was probably that she could leave the burrow for extended feeding excursions, whereas alone it would have to either completely forego nourishment or, as is the case with the Porcellio species mentioned, must greatly restrict the spectrum of food that it can use (to that which is to be found only a short distance from the burrow and which can eas-ily be carried inside the burrow). This could be a disadvantage, especially during egg production. Necessary to the male's successful defense of the burrow is that he recognises his female. Studies of the Canary Island Porcellio species have shown over which pathways and under what selection pressures the recopinon of individuals, as is realized mHemilepistus, could have evolved. Females can bind males longer, the longer the period of their attraction is extended: Females olHemilepistus reaumuri have been proven to be al·ready att-ractive before they are ready to copulate and still remain attractive after they have copulated. The conse-quences of the last fact will be discussed. The question of why the males remain with the females after the parturial ecdysis will also be discussed: The great danger to the male's investment resulting from a tooi early abandoning, and the low probability of successfully finding another partner after a later abandomng should prevent a positive balance in the males' cost-effecriveness calculations.
7-Azatetracyclo[4.1.0.0<sup>2,4</sup>.0<sup>3,5</sup>]heptan - ein neues Valenzisomeres des Azepins
(1979)
No abstract available
Purified mitochondrial DNA (mitDNA) from ovaries ofXenopus lae vis was injected into the nuclei (germinal vesicles) of large viteUogenic oocytes of the same organism and examined by electron microscopy ofthe spread nuclear contents. Normally located nuclei of untreated oocytes as weil as peripherally translocated nuclei of centrifuged oocytes were used. In addition, oocyte nuclei isolated and incubated under liquid paraffin oil were injected with DNA. The integrity oftranscriptional structures of endogenous chromosomal (Iampbrush chromosomes) and extrachromosomal (nucleoli) genes of the injected nuclei was demonstrated. Microinjected mitDN A was identified as circles of chromatin exhibiting polynucleosome-like organization and a me an contour length of 2.6 J.Lm, corresponding to a compaction ratio of the mitDN A of about 2 : I. This DNA packing ratio is similar to that observed after preparation of various kinds of native chromatin in low salt buffers. The chromatin circles formed from injected mitDNA only very rarely exhibited lateral fibrils suggestive of transcriptional activity. These results suggest that purified mitDNA can be transformed to normally structured chromatin when exposed to oocyte nuclear contents but is rarely , if at all , transcribed in this form and in this environment.
Antibodies to calf thymus histone H2B were purified by chromatography on DEAE-cellulose and injected into oocyte nuclei of Pleurodeles waltlii. As shown by indirect immunofluorescence these antibodies cross-reacted strongly with corresponding histones associated with lampbrush chromosomes. Shortly after injection the lateral loops of the chromosomes retracted into the chromomeres and by 3 h postinjection the 'lampbrush' appearance was completely lost and the chromosomes appeared in light-microscopic preparations as rod-like structures consisting of 10ngitudina11y coalesced chromomeres. In control oocytes injected with non-immune immunoglobulins or antibodies against a ubiquitous transcript-associated protein no morphological alterations of the lampbrush chromosomes could be observed. Electron microscopic spreads of chromosomes prepared at various times after injection of anti-H2B revealed a progressive loss of transcriptional complexes from the loop axes. Finally, higher-order chromatin configurations, like supranuc1eosomal globules (' superbeads ') or cable-like chromatin strands 50- 60 nm thick predominated, indicating complete transcriptional inactivation of a11 chromosomal regions. The results indicate that H2B antibodies react specifically with his tones associated with the transcribed DNA of lateral loops in their native state. The resulting antigenantibody complexes seem to inhibit progression of the R A polymerases along the template, thus causing the premature release of transcripts, a process analogous to the stripping effect of actinomycin D. The demonstration of histones associated with heavily transcribed regions, which are not compacted into nucleosomes but largely extended, supports the current concept that unfolding of nucleosomes to a110w transcription of the DNA does not involve dissociation of histones. In contrast, amplified ribosomal RNA genes are unaffected by injected HzB antibodies. This does not necessarily indicate absence of his tones from nucleolar chromatin, since we do not know whether it is accessible in vivo to antibodies or whether the histone antigenie determinants are masked by the presence of other proteins. The technique of injecting specific antibodies should be widely applicable when analysing the in vivo distribution of chromosomal components at the electron-microscopic level and when studying complex metabolie processes, like the cleavage and modification of RNA, by selective inhibition of defined enzymic steps.
Xiphophorus andersi n. sp. from the Rio Atoyac, Vera Cruz, Mexico is described: lang head, moderately slender body, large dark black spar at the basis of the anal fin; adult male with short sword-like caudal appendage; rip of ray 5a of gonopodium without a developed claw. Xiphophorus andersi n. sp. differs by the combination of distinct characters from all the other species of the genus known so far. The new species shows features of both the so-called platyfish species group and the so-called swordtail species group.
The determination of a covalent binding of radioactive chemieals to DNA in intact mammalian organisms is proposedas a short-term test for carcinogenicity. The effectiveness of covalent binding to rat liver DNA correlates well with the hepatocarcinogenicity known from long-term bioassays. The binding indices range over more than five orders of rriagnitude between the strongest hepatocarcinogen aflatoxin B 1 and the limit of detection of a binding with 100 f-LCi 14C-labelled chemical. The order of magnitude of binding is therefore a surprisingly good quantitative measure for carcinogenicity. The pattern of DNA binding sites is important especially for small alkylating agents where the determination of total binding might indicate a higher carcinogenic potency than is actually observed.
The influence of microsomal (mAHH) and nuclear (nAHH) aryl hydrocarbon hydroxylase activity on the covalent binding of t:titiated benzo(a)pyrene to rat liver DNA was evaluated in vivo. Induction ofmAHH was obtained after phenobarbitone treatment (180% of control), which increased DNA binding to 210%, but left the nAHH unchanged. mAHH and nAHH were slightly indilced with dieldrin (130% and 120%), but the binding remairred unchanged. The increasing effect of mAHlt as weil as the possibly decreasing effect of nAHH induction on the binding became obvious when the data of 11 individual rats were used to solve the equation Binding = aX(mAHH) + bX(nAHH) + c. Multiple linear regression analysis resulted in positive values for a and c, a negative value for b, and a multiple correlation coefficient R = 0.82. An influence of other enzymes involved in the metabolism of benzo(a)pyrene cannot be excluded. The Study shows clearly that the binding of a foreign compound to DNA in vivo is not only dependent on microsomal enzyme activities but also on nuclear activities even if the latter are considerably lower than those of mic'rosomes.
no abstract available
The A TPase eomplex has been isolated from mitoehondria of N eurospora crassa by immunologieal teehniques. The protein ean be obtained rapidly and qua ntitatively in high purity by miero- or large-seale immunopreeipitation. Immunopreeipitation has been applied to labeled and doubly labeled mitoehondrial proteins in order to investigate the number and moleeular weights of subunit polypeptides , the site of synthesis of subunit polypeptides, and the dieycIohexyIcarbodiimide-binding protein . The A TPase complex obtained by large-seale immunopreeipitation has been used as starting ma terial for the isolation of hydrophobie polypeptides.
The fungus Neurospora crassa represents a eukaryotic cell with high biosynthetic activities. Cell mass doubles in 2-4 hr during expone ntial growth , even in simple salt media with sucrose as the sole carbon source. The microorgani sm forms a mycelium of long hyphae durlng vegetative growth . The mitochondria can be isolated under relatively gentle condi tions since a few breaks in the threadlike hyphae are sufficient to cause the outflow of the organelles. This article describes two methods for the physical disruption of the hyphae : (I) The cell s are opened in a grind mill between two rotating corundum di sks. This is a continuous and fast procedure and allows large- and small-scale preparations of mitochondria. (2) Hyphae are ground with sand in a mortar and pestle. This procedure can be applied to microscale preparations of mitochondria starting with minute amounts of cells. Other procedures for the isolation of Neurospora mitochondria after the physical di sruption or the enzymatic degradation of the cell wall have been described elsewhere
No abstract available.
No abstract available.