Memoirs: The Structure of the Somatic Chromosomes of Alstroemeria and Bomarea

1934 ◽  
Vol s2-77 (305) ◽  
pp. 49-75
Author(s):  
FRANK W. JANE
Keyword(s):  
Early Prophase ◽  
Botanic Gardens ◽  
Botanic Garden ◽  
Metaphase Chromosomes ◽  
Birkbeck College ◽  
Late Prophase ◽  
Sister Chromatids ◽  
Spiral Form ◽  
Friendly Criticism ◽  
The University

1. Investigations have been made on the chromatin throughout mitosis in Alstroemeria and Bomarea, and an attempt has been made to interpret the observations. 2. Anaphase chromosomes contain single or double spirals and often chromomeres. The spiral chromonemata are held to arise from the chromomeres. 3. The resting reticulum is formed partly from the remains of the spirals, partly from the telophasic anastomoses between adjacent chromosomes. The chromomeres form the net-knots. 4. The spiral chromosomes seen in early prophase are not regarded as homologous with the anaphase chromonema. It is not certain that all the chromosomes of a nucleus assume the spiral form during prophase. 5. The paired chromatids arise during prophase by the connecting up of adjacent daughter chromomeres into two strips of chromatin. The chromosomes do not split longitudinally at any stage. 6. Connexions between the sister chromatids are regarded as remnants of the chromonema of the previous anaphase. In this respect the interpretation agrees with Martens theory of bilateral repartition. 7. Chromomeres appear in prophase as the chromatids emerge from the spiral stage. They cease to be visible in late prophase as the chromatids thicken and become densely chromatic. 8. Prolonged destaining of the early metaphase chromosomes shows that the chromomeres are still present. Each has divided to form two daughter chromomeres. Between the chromomeres on opposite sides of the chromatid appear connexions, the new chromonema. This investigation was begun at Birkbeck College, University of London, while I was the recipient of a maintenance grant from the Department of Scientific and Industrial Research. My thanks are due to the Trustees of the Dixon Fund for the loan of a suitable microscope; to the Directors of the Eoyal Botanic Gardens, Kew, the Chelsea Physic Garden, and the University Botanic Garden, Cambridge, for material; and especially to Professor Dame Helen Gwynne-Vaughan, under whose direction the work was carried out and who has encouraged me with friendly criticism and advice.

scholarly journals ENDOWMENT STRATEGIES FOR THE UNIVERSITY OF DELAWARE BOTANIC GARDENS

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 495A-495 ◽  
Author(s):  
Matt Stephens ◽  
Melody Gray ◽  
Edward Moydell ◽  
Julie Paul ◽  
Tree Sturman ◽  
...  
Keyword(s):  
Task Force ◽  
The United States ◽  
University Of Delaware ◽  
Botanic Gardens ◽  
Botanic Garden ◽  
College Of Agriculture ◽  
Public Gardens ◽  
Institutional Knowledge ◽  
Key Staff ◽  
The University

The University of Delaware Botanic Gardens (UDBG) is at a critical juncture in its development. Momentum of shared interest at the University of Delaware and the College of Agriculture and Natural Resources favors the Gardens' advancement as an institution. Having identified endowment planning as a critical and immediate need for UDBG, the goal of this research was to gather pertinent institutional knowledge from select university-based public gardens throughout the United States that had already created an endowment. Key staff were interviewed during the summer of 2005 at Cornell Plantations, JC Raulston Arboretum, Minnesota Landscape Arboretum, and the State Botanic Garden of Georgia. Valuable insights into the procurement and management of endowments within a university-based garden environment were gained through these interviews. Utilizing these results, as well as input from an advisory Task Force, specific recommendations for the University of Delaware Botanic Gardens were made from within the following topic areas: Organizational Structure, Planning, Current Strategies, The Endowment, and The Donor.

scholarly journals The role of university botanic gardens in implementing the third mission

2021 ◽  
Vol 296 ◽  
pp. 03002
Author(s):  
Tatyana Chernysheva
Keyword(s):  
Public Spaces ◽  
Educational Policies ◽  
Urban Residents ◽  
Botanic Gardens ◽  
Third Mission ◽  
Botanic Garden ◽  
The Third ◽  
The University ◽  
Russian Universities

The paper reveals a new dimension of implementing the third mission of a university - through the activities rolled-out by Russian universities in their botanic gardens. For urban residents, botanic gardens, in addition to their main functions, are gradually becoming a place for integrating different population groups, from schoolchildren to pensioners. These public spaces conduct active educational policies aimed at many segments of a broader university community, taking into account the experience of regional environmental organizations and international Associations of Botanic Gardens. The author argues that the ecological vector is a priority for productive communication of a university with regional and global audiences at the site of its Botanic Garden, which becomes a measure of the university entering upon the way of sustainable development

scholarly journals ELECTRON MICROSCOPIC OBSERVATIONS ON THE SUBMICROSCOPIC MORPHOLOGY OF THE MEIOTIC NUCLEUS AND CHROMOSOMES

1956 ◽  
Vol 2 (6) ◽  
pp. 785-796 ◽  
Author(s):  
E. De Robertis
Keyword(s):  
Meiotic Prophase ◽  
Early Prophase ◽  
Electron Microscopic ◽  
Metaphase Chromosomes ◽  
Late Prophase ◽  
Continuous Transition ◽  
Thin Sections ◽  
Nucleolar Material ◽  
Mean Diameter ◽  
The Mean

Thin sections of the testicular follicles of the grasshopper Laplatacris dispar were studied under the electron microscope. In the primary spermatocytes, during meiotic prophase, three main regions can be recognized within the nucleus: (1) the nucleolus and associated nucleolar material; (2) the interchromosomal regions with the dense particles; and (3) the chromosomes. The nucleolus is generally compact and is surrounded by nucleolar bodies that comprise aggregations of dense round particles 100 to 250 A in diameter. A continuous transition can be observed between these particles and those found isolated or in short chains in the interchromosomal spaces. Particles of similar size (mean diameter of 160 A) can be found associated with the nuclear membrane and in the cytoplasm. The chromosomes show different degrees of condensation in different stages of meiotic prophase. The bulk of the chromosome appears to be made of very fine and irregularly coiled filaments of macromolecular dimensions. Their length cannot be determined because of the thinness of the section but some of them can be followed without interruption for about 1000 to 2000 A. The thickness of the chromosome filaments seems to vary with different stages of prophase and in metaphase. In early prophase, filaments vary between 28 ± 7 A and 84 ± 7 A with a mean of 47 A, in late prophase the mean is about 70 A. In metaphase the filaments vary between 60 and 170 A with a mean of about 100 A. Neither the prophase nor the metaphase chromosomes have a membrane or other inhomogeneities. The finding of a macromolecular filamentous component of chromosomes is discussed in relation to the physicochemical literature on nucleoproteins and nucleic acids and as a result it is suggested that the thinnest chromosome filaments (28 ± 7 A) probably represent single deoxyribonucleoprotein molecules.

scholarly journals The Cultivation of Titan Arum (Amorphophallus titanum) :

2007 ◽  
pp. 69-86
Author(s):  
Wolfram Lobin ◽  
Michael Neumann ◽  
Markus Radscheit ◽  
Wilhelm Barthlott
Keyword(s):  
Plant Species ◽  
Ex Situ Conservation ◽  
Natural Habitat ◽  
Ex Situ ◽  
Flagship Species ◽  
Botanic Gardens ◽  
Wild Populations ◽  
Botanic Garden ◽  
The University ◽  
Garden Community

One of the most exciting plant species is the Titan Arum, Amorphophallus titanum, which can truly be regarded as a flagship species for botanic gardens. Wild populations suffer from an increasing pressure on their natural habitat, but botanic gardens can play an important role in the ex-situ conservation of the species. The cultivation of A. titanum is not easy but it offers an irresistible challenge for any keen horticulturist. The University of Bonn Botanic Gardens (Germany) has more than seventy years of experience in the cultivation of this giant and the purpose of this paper is to help the botanic garden community to achieve success in the cultivation of this fascinating plant.

A mutation in the spindle checkpoint arresting meiosis II in Brachiaria ruziziensis

Genome ◽  
2003 ◽  
Vol 46 (4) ◽  
pp. 724-728 ◽  
Author(s):  
Claudicéia Risso-Pascotto ◽  
Maria Suely Pagliarini ◽  
Cacilda Borges do Valle
Keyword(s):  
Nuclear Envelope ◽  
Spindle Checkpoint ◽  
Low Frequency ◽  
Early Prophase ◽  
Late Prophase ◽  
Brachiaria Ruziziensis ◽  
Sister Chromatids ◽  
Wide Range

Cytological characterization of BRA005568 accession of Brachiaria ruziziensis (2n = 2x = 18) showed a totally unexpected high frequency of abnormal meiotic products, from triads to hexads, and also tetrads with micro nuclei or microcytes. Meiosis I had a low frequency of abnormalities, mainly related to the chiasma terminalization process. In meiosis II, however, frequency of abnormalities increased exceptionally. Early prophase II was normal with the chromosome set enclosed by the nuclear envelope. However, in late prophase II, owing to the breakdown of the nuclear envelope, the chromosomes were scattered in the cytoplasm. Some chromosomes did not reach the metaphase II plate and remained scattered. The behavior of sister cells was inconsistent. While in one cell the chromosomes were totally aligned at the metaphase II plate, in the other they could be found completely scattered, leading to an asynchronous cell division. Cells with scattered chromosomes were unable to progress in meiosis. Thus, anaphase II failed to occur and sister chromatids were not released. Cells with non-aligned chromosomes in the metaphase II plate did not receive the "go ahead" sign to initiate anaphase II. Consequently, the scattered chromosomes produced telophase II nuclei of different sizes in situ. The asynchronous behavior led to the formation of a wide range of meiotic products. Results suggest that the present accession contains a mutation affecting the spindle checkpoint that arrests the second meiotic division.Key words: Brachiaria ruziziensis, meiosis II, microsporogenesis, mutation, spindle checkpoint.

scholarly journals Visualization of early chromosome condensation

2004 ◽  
Vol 166 (6) ◽  
pp. 775-785 ◽  
Author(s):  
Natashe Kireeva ◽  
Margot Lakonishok ◽  
Igor Kireev ◽  
Tatsuya Hirano ◽  
Andrew S. Belmont
Keyword(s):  
Large Scale ◽  
Mitotic Chromosome ◽  
Chromosome Structure ◽  
Early Prophase ◽  
Axial Distribution ◽  
Metaphase Chromosomes ◽  
Topoisomerase Iiα ◽  
Late Prophase ◽  
Chromatin Folding ◽  
Structural Maintenance Of Chromosomes

Current models of mitotic chromosome structure are based largely on the examination of maximally condensed metaphase chromosomes. Here, we test these models by correlating the distribution of two scaffold components with the appearance of prophase chromosome folding intermediates. We confirm an axial distribution of topoisomerase IIα and the condensin subunit, structural maintenance of chromosomes 2 (SMC2), in unextracted metaphase chromosomes, with SMC2 localizing to a 150–200-nm-diameter central core. In contrast to predictions of radial loop/scaffold models, this axial distribution does not appear until late prophase, after formation of uniformly condensed middle prophase chromosomes. Instead, SMC2 associates throughout early and middle prophase chromatids, frequently forming foci over the chromosome exterior. Early prophase condensation occurs through folding of large-scale chromatin fibers into condensed masses. These resolve into linear, 200–300-nm-diameter middle prophase chromatids that double in diameter by late prophase. We propose a unified model of chromosome structure in which hierarchical levels of chromatin folding are stabilized late in mitosis by an axial “glue.”

Staining plant cells with silver. II. Chromosome cores

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 900-908 ◽  
Author(s):  
Stephen M. Stack
Keyword(s):  
Silver Staining ◽  
Plant Cells ◽  
Lilium Longiflorum ◽  
Early Prophase ◽  
Metaphase Chromosomes ◽  
Homologous Chromosomes ◽  
Meiotic Chromosomes ◽  
Plant Chromosomes ◽  
Sister Chromatids ◽  
A New Technique

A new technique called salt-nylon silver staining has been used to stain cores in the chromosomes of Lilium longiflorum. Cores are visible in both mitotic and meiotic chromosomes. In C-metaphase chromosomes, a thin core is coiled to form a thick core in each chromatid. In early prophase I of meiosis, silver-stained axial cores and synaptonemal complexes show no indication of coiling before their disappearance in early diplotene. In diakinesis, pairs of thin cores reappear in large major coils. These cores can be seen to cross over between homologous chromosomes. By metaphase I, thin cores coil to form thick cores, which themselves spiral in major coils. The most striking appearance of the cores occurs during anaphase I, when homologous chromosomes separate and sister chromatids swing apart to display thick cores in major coils. During meiosis II cores are in minor coils embedded in elongate chromosomes that show relic major coiling. These observations indicate that plant chromosomes have silver-stainable cores that are comparable with cores that have been reported in the chromosomes of mammals and grasshoppers.Key words: chromosome cores, silver staining, mitosis, meiosis, plants.

Advances in imaging SIMS studies of stained and BrdU-labelled human metaphase chromosomes

1995 ◽  
Vol 53 ◽  
pp. 932-933
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
R. Espinosa ◽  
M. M. Le Beau
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Analytical Sensitivity ◽  
Metaphase Chromosomes ◽  
Banding Patterns ◽  
Sector Mass Spectrometer ◽  
Staining Methods ◽  
The University ◽  
Secondary Ion ◽  
Better Than

We have shown previously that isotope-labelled nucleotides in human metaphase chromosomes can be detected and mapped by imaging secondary ion mass spectrometry (SIMS), using the University of Chicago high resolution scanning ion microprobe (UC SIM). These early studies, conducted with BrdU- and 14C-thymidine-labelled chromosomes via detection of the Br and 28CN- (14C14N-> labelcarrying signals, provided some evidence for the condensation of the label into banding patterns along the chromatids (SIMS bands) reminiscent of the well known Q- and G-bands obtained by conventional staining methods for optical microscopy. The potential of this technique has been greatly enhanced by the recent upgrade of the UC SIM, now coupled to a high performance magnetic sector mass spectrometer in lieu of the previous RF quadrupole mass filter. The high transmission of the new spectrometer improves the SIMS analytical sensitivity of the microprobe better than a hundredfold, overcoming most of the previous imaging limitations resulting from low count statistics.

Disposing of John Lindley's library and herbarium: the offer to Australia

2008 ◽  
Vol 35 (1) ◽  
pp. 15-70 ◽  
Author(s):  
A. M. LUCAS
Keyword(s):  
United Kingdom ◽  
Botanic Gardens ◽  
Final Disposal ◽  
The United Kingdom ◽  
Royal Horticultural Society ◽  
Royal Botanic Gardens ◽  
United Kingdom Government ◽  
The University ◽  
Joseph Hooker

Shortly before he died, John Lindley decided to dispose of his herbarium and botanical library. He sold his orchid herbarium to the United Kingdom government for deposit at the Royal Botanic Gardens, Kew, and then offered his library and the remainder of his herbarium to Ferdinand Mueller in Melbourne. On his behalf, Joseph Hooker had earlier unsuccessfully offered the library and remnant herbarium to the University of Sydney, using the good offices of Sir Charles Nicholson. Although neither the University of Sydney nor Mueller was able to raise the necessary funds to purchase either collection, the correspondence allows a reconstruction of a catalogue of Lindley's library, and poses some questions about Joseph Hooker's motives in attempting to dispose of Lindley's material outside the United Kingdom. The final disposal of the herbarium to Cambridge and previous analyses of the purchase of his Library for the Royal Horticultural Society are discussed. A list of the works from Lindley's library offered for sale to Australia is appended.

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