Plant phenolic compounds and the isolation of plant enzymes

https://science.sciencemag.org/content/sci/160/3825/272.full.pdf

Specific Gene Amplification in Oocytes Oocyte nuclei contain extrachromosomal replicas of the genes for ribosomal RNA

I. Introduction.- II. Ribosomal Genes.- II. 1. Definitions.- II.2. Ribosomal RNA Genes.- II.2.1. Multiplicity.- II.2.2. Chromosomal Location.- II.2.3. Extrachromosomal rRNA Genes.- II.2.4. Organization and Structure.- II.2.4.1. Saccharomyces cerevisiae.- II.2.4.2. Tetrahymena.- II.2.4.3. Drosophila.- II.2.4.4. Xenopus laevis.- II.2.4.5. Higher Plants.- II.2.4.6. Mammalia.- II.2.5. General Features.- II.3. 5 S rRNA Genes.- II.3.1. Number and Chromosomal Location.- II.3.2. Organization and Structure.- II.4. Ribosomal Protein Genes.- II.5. Synopsis.- III. Transcription of Ribosomal Genes.- III. 1. Components of the Transcription Complex.- III. 1.1. RNA Polymerases.- III. 1.2. Nucleolar rDNA and r-Chromatin.- III.2. The Transcription Process >.- III.2.1. Topology of Primary Pre-rRNA.- III.2.2. Morphology of Transcribed rRNA Genes.- III.2.3. Transcribed and Non-Transcribed r-Chromatin.- III.2.4. Primary Transcripts and Primary Pre-rRNA.- III.2.5. Transcription Initiation and Termination.- III.2.5.1. Initiation.- III.2.5.2. Termination.- III.2.6. Transcription in vitro.- III.3. Transcription of 5 S rRNA Genes.- III.4. Transcription of r-Protein Genes.- III.5. Synopsis.- IV. Maturation of Preribosomes.- IV. 1. Structure of Primary Pre-rRNA.- IV. 1.1. Size and Primary Structure.- IV. 1.2. Modifications.- IV. 1.3. Conformation.- IV.2. Pre-rRNA Maturation Pathways.- IV.2.1. General Considerations.- IV.2.2. Common Pattern of Pre-rRNA Maturation.- IV.2.3. Multiplicity of Maturation Pathways.- IV. 2.4. Enzyme Mechanisms.- IV. 3. Preribosomes: Structure and Maturation.- IV. 4. Synopsis.- V. Molecular Architecture of the Nucleolus.- V. 1. Introduction.- V.2. Nucleolus Organizer.- V. 2.1. Chromosomes.- V.2.2. Interphase Nuclei.- V.3. Fibrillar and Granular Components.- V.3.1. The Fibrillar Component.- V.3.2. The Granular Component.- V.4. The Nucleolus and Other Nuclear Structures.- V.4.1. Nucleolus-Associated Chromatin.- V.4.2. The Junction with the Nuclear Envelope.- V.5. The Nucleolar Matrix.- V.6. Macromolecular Constituents.- V.6.1. DNA and RNA.- V. 6.2. Nucleolar Proteins.- V.6.2.1. General.- V.6.2.2. Ag-NOR Protein(s).- V. 6.2.3. Nucleolar Antigens.- V. 7. Outline.- VI. Regulation.- VI. l. General Considerations.- VI.2. Transscriptional Control.- VI. 2.1. Transitions in the State of Expression of rRNA Genes.- VI. 2.1.1. Inactive r-Chromatin.- VI.2.1.2. Potentialy Active and Transcribed rRNA Genes.- VI.2.2. Control of Transcription Rate.- VI.2.2.1. Role of RNA Polymerase I.- VI.2.2.2. Supply of Nucleoside-5'-Triphosphates...- VI.2.2.3. Role of Protein Synthesis.- VI.3. Posttranscriptional Control.- VI.3.1. Synthesis and Supply of r-Proteins.- VI.3.2. The Role of Pre-rRNA Structure.- VI.3.3. The Role of 5 S rRNA.- VI.3.4. Critical Control Sites.- VI.3.4.1. Alternative Processing Pathways and Intranuclear Degradation of Preribosomes and Ribosomes.- VI.3.4.2. Release From the Nucleolus and Nucleo- Cytoplasmic Transport of Ribosomes.- VI.3.4.3. Turnover of Ribosomes.- VI.4. Autogeneous Regulation of Ribosome Biogenesis in Eukaryotes: A Model.- VI.5. Synopsis.- VII. Ribosome Biogenesis in the Life Cycle of Normal and Cancer Cells.- VII. 1. Nucleologenesis and Nucleololysis.- VII. 1.1. Nucleoli and Ribosome Biogenesis During the Mitotic Cycle.- VII. 1.2. Nucleologenesis.- VII. 1.3. Nuclyeololysis.- VII.2. Inhibition of Ribosome Biogenesis.- VII.2.1. Inhibitors Interacting With DNA and Chromatin.- VII.2.2. Inhibitors That Act on RNA Polymerases.- VII.2.3. Inhibitors of Nucleoside-5'-Triphosphate Formation.- VII.2.4. The Effects of Analogues Incorporated into Polyribonu- cleotide Chains.- VII.2.5. Inhibitors of Protein Synthesis.- VII.2.6. Interpretation of Nucleolar Alterations.- VII.2.6.1. Nucleolar Segregation.- VII.2.6.2. Nucleolar Spherical Bodies and Perichromatin Granules.- VII.2.6.3. Microspherules.- VII.2.6.4. Nucleolar Fragmentation.- VII.3. Growth Transitions.- VII.3.1. Modulation of Growth Rates in Yeasts.- VII.3.2. Activation of Lymphocytes.- VII.3.3. Growth Stimulation of Cultured Cells.- VII.3.4. Differentiation of Myoblasts in Culture.- VII.3.5. Regeneration of Rat Liver.- VII.4. Senescent and Cancer Cells.- VII.4.1. Senscent Cells and Tissues.- VII.4.2. Cancer Cells.- VII.5. Synopsis.- References.

The nucleolus and ribosome biogenesis

Vitellogenesis and Oocyte Growth in Nonmammalian Vertebrates

Patterns of chondrichthyan reproduction and development are diverse. Species either are reproductively active throughout the year, or have a poorly defined annual cycle with one or two peaks of activity, or have a well defined annual or biennial cycle. Based on embryological origin and adult morphology, their reproductive system is more similar to tetrapods than to teleosts. Primordial germ cells are of endodermal origin. The Wolffian ducts in males and Mullerian ducts in females become the functional urogenital ducts. Differentiation is under hormonal control. Unusual features of the reproductive system include an epigonal organ in males and females. It contains lymphoid and hemopoietic tissue. Leydig's gland, a modified region of the kidney, produces seminal fluid. In some species, sperm passing through the vas deferens, is enclosed in spermatophores. Rotating about their long axis, helical spermatozoa can move forward or reverse direction. Spermatogenesis often occurs in bicellular units, spermatocysts. These consist of a spermatogonium enclosed in a Sertoh cell. Fertilization is internal. Claspers, modified portions of the pelvic fins act as intromittent organs. In many viviparous sharks and rays, the female reproductive system is asymmetrical. Eggs of some sharks are the largest known cells. Yolk platelets contain lipovitellin. Oocytes have lampbrush chromosomes. Eggs released from the ovary into the body cavity are transported by ciliary action to the ostium of the oviduct. There they are fertilized. Physiological polyspermy is normal. The shell gland, a specialized region of the anterior oviduct, functions both in long term sperm storage and in egg case production. Egg cases of sharks and skates consist of unique collagenous protein with a 400 A period, organized as a cholesteric liquid crystal. Chimaeroid egg cases contain 550 A pseudotubules in orthogonal lattices. In small sharks, males copulate by coiling around the female. A parallel position is assumed by large sharks. Skates and rays copulate with ventral surfaces apposed or by a dorsal approach. Biting is a pre-copulatory release mechanism. Parental care, except for selective oviposition, is lacking. Heavily yolked eggs undergo meroblastic, discoidal cleavage. Development is lengthy, shortest (2–4 months) in rays, longer in skates (3–8 months) and longest (9–22 months) in sharks and chimaeras. Most sharks and all rays are viviparous. Chimaeras, skates, and some sharks are oviparous. Viviparity either involves a yolk sac placenta or is aplacental. If aplacental, the embryo derives nutrients either from yolk reserves, or by intra-uterine embryonic cannibalism, or from placental analogues which secrete “uterine milk.” Phylogenetic position, geographical distribution, benthic vs. pelagic habitat, adult size, egg-embryo size, feeding ecology, and embryonic osmoregulation are factors in the retention of oviparity or the evolution of viviparity.

Reproduction and Development in Chondrichthyan Fishes

The yolk platelets of mature eggs and young embryonic cells of all amphibian species studied (Rana pipiens, Triturus pyrrhogaster, Diemictylus viridescens, Rana nigromaculata, and Bufo vulgaris) have a superficial layer of fine particles or fibrils (ca. 50 A in diameter), a central main body with a crystalline lattice structure, and an enclosing membrane approximately 70 A in thickness. Electron micrographs of the main body reveal hexagonal net (spacing ca. 70 A), square net (spacing ca. 80 A), and parallel band (spacing from 35 to 100 A but most frequent at ca. 70 A) patterns. The crystalline structure is believed to be a simple hexagonal lattice made of closely packed cylindrical rods. Each rod is estimated to be about 80 A in diameter and 160 A in length.

/pdf/studies-on-amphibian-yolk-1-the-ultrastructure-of-the-yolk-49rg8fiv4y.pdf

Studies on amphibian yolk 1. The ultrastructure of the yolk platelet.

The site of H3-uridine incorporation and the fate of labeled RNA during early embryo-genesis of the newt Triturus pyrrhogaster were studied with electron microscopic autoradiography. Isolated ectodermal and mesodermal tissues from the embryos were treated in H3-uridine for 3 hours and cultured in cold solution for various periods before fixation with OsO4 and embedding in Epon. At the blastula stage, the only structural component of the nucleus seen in electron micrographs is a mass of chromatin fibrils. At the early gastrula stage, the primary nucleoli originate as small dense fibrous bodies within the chromatin material. These dense fibrous nucleoli enlarge during successive developmental stages by the acquisition of granular components 150 A in diameter, which form a layer around them. Simultaneously larger granules (300 to 500 A) appear in the chromatin, and they fill the interchromatin spaces by the tail bud stage. Autoradiographic examination has demonstrated that nuclear RNA synthesis takes place in both the nucleolus and the chromatin, with the former consistently showing more label per unit area than the latter. When changes in the distribution pattern of radioactivity were studied 3 to 24 hours after immersion in isotope at each developmental stage, the following results were obtained. Labeled RNA is first localized in the fibrous region of the nucleolus and in the peripheral region of chromatin material. After longer culture in non-radioactive medium, labeled materials also appear in the granular region of the nucleolus and in the interchromatin areas. Further incubation gives labeling in cytoplasm.

/pdf/electron-microscopic-examination-of-the-sites-of-nuclear-rna-4w4iueexie.pdf

Electron microscopic examination of the sites of nuclear rna synthesis during amphibian embryogenesis.

Studies on amphibian yolk. 5. electron microscopic observations on the utilization of yolk platelets during embryogenesis.

An electron microscopic study of wolffian lens regeneration in the adult newt.

Previous methods which employed simple sucrose or salt solutions to isolate yolk platelets have failed to preserve their superficial layer, and the preparations obtained generally exhibit some contamination when observed with the light or electron microscope. When yolk platelets are suspended in a sucrose-polyvinylpyrrolidinone medium, however, they remain relatively intact and their superficial layer is not lost to the medium. A method, which takes advantage of this fact, is described for the isolation of frog (Rana pipiens) yolk platelets which are free from nuclear contamination and practically free from cytoplasmic contamination. After such platelets are treated with distilled water, the superficial layer is no longer seen and a new dense and granular matrix is frequently found surrounding the crystalline main body. The significance of this and other observations concerning the effects of calcium and ethylenediamine tetraacetate are discussed.

/pdf/studies-on-amphibian-yolk-2-the-isolation-of-yolk-platelets-362trsvht5.pdf

Shuichi Karasaki

Papers

Studies on amphibian yolk 1. The ultrastructure of the yolk platelet.

Electron microscopic examination of the sites of nuclear rna synthesis during amphibian embryogenesis.

Studies on amphibian yolk. 5. electron microscopic observations on the utilization of yolk platelets during embryogenesis.

An electron microscopic study of wolffian lens regeneration in the adult newt.

STUDIES ON AMPHIBIAN YOLK : 2. The Isolation of Yolk Platelets from the Eggs of Rana pipiens