Morphological and anatomical development in the Vitaceae. V. Vegetative and floral development in Ampelopsis brevipedunculata

1989 ◽  
Vol 67 (8) ◽  
pp. 2371-2386 ◽  
Author(s):  
Jean M. Gerrath ◽  
Usher Posluszny
Keyword(s):  
Apical Meristem ◽  
Floral Development ◽  
Three Dimensional ◽  
Growing Season ◽  
Axillary Buds ◽  
Histological Techniques ◽  
Basal Ring ◽  
Stamen Primordia ◽  
The Common ◽  
Subsequent Activity

The vegetative and floral development of Ampelopsis brevipedunculata was studied using both three-dimensional and histological techniques. An uncommitted primordium (which usually develops into a tendril in young seedlings and a cymose inflorescence in mature plants) is initiated opposite every leaf on the flank of the shoot apical meristem. Flowers are hermaphroditic, pentamerous, and protandrous. The sepals are initiated spirally, and form a calyx unit as the result of subsequent activity of a basal ring primordium. The common petal–stamen primordia are initiated simultaneously, but differentiate into petals and stamens unidirectionally. The gynoecium is initiated as a ring primordium, which produces two septa from the inner gynoecium wall. Two bitegmic, anatropus ovules arise from the base of each septum. At maturity the gynoecium is superior and two-loculed. Pollen is tricolporate. A nectar-secreting disc arises from the base of the ovary. The fruit is a turquoise-blue berry, containing one to four seeds. Axillary buds, present at each node, develop sylleptically and normally abscise at the end of the growing season. A vertical series of as many as six serial axillary buds develop basipetally to form the overwintering buds, which are not externally visible.

Morphological and anatomical development in the Vitaceae. IV. Floral development in Parthenocissus inserta

1989 ◽  
Vol 67 (5) ◽  
pp. 1356-1365 ◽  
Author(s):  
Jean M. Gerrath ◽  
Usher Posluszny
Keyword(s):  
Floral Development ◽  
Three Dimensional ◽  
Floral Ontogeny ◽  
Inflorescence Branch ◽  
Stamen Primordia ◽  
Floral Apex

The floral ontogeny of Parthenocissus inserta, based on histological and three-dimensional observations, is presented. The inflorescence primordium arises in a leaf-opposed position at two of three nodes. It becomes subtended by a bract, and then bifurcates equally to form a lateral and a main arm. Inflorescence branches are initiated on both arms to form a series of dichasia. The transition from inflorescence branch primordium to floral primordium is marked by the initiation of three sepal primordia. Subsequently a ring primordium forms as the fourth and fifth sepal primordia are initiated, resulting in a calyx which encircles the floral apex. Petals and stamens arise simultaneously as five common petal–stamen primordia, alternating with the sepals. They bifurcate to form separate petal and stamen primordia. The petals are greenish, valvate, hooded, and are separate at maturity. The tetrasporangiate anthers are introrse and pollen is tricolporate. The gynoecium arises as a ring primordium. Two septa arise from the inner gynoecial wall and the floral apex, and will eventually form an essentially two-loculed superior ovary. Two ovules are initiated from the base of each septum. Each of the four ovules is anatropous and bitegmic at maturity. A disc arises from the base of the gynoecium. It appears as five pinkish protuberances of the ovary base at maturity and secretes a nectarlike substance. The fruit is a one- to four-seeded blue-black berry.

Synthetic Strategies to Access Heteroatomic Spirocentres Embedded in Natural Products

Synthesis ◽  
2021 ◽  
Author(s):  
Michael P. Badart ◽  
Bill C. Hawkins
Keyword(s):  
Natural Products ◽  
Heterocyclic Compound ◽  
Chemical Space ◽  
Three Dimensional ◽  
Coupling Reactions ◽  
Conjugate Additions ◽  
Biological Targets ◽  
Compound Libraries ◽  
The Common ◽  
Significant Attention

AbstractThe spirocyclic motif is abundant in natural products and provides an ideal three-dimensional template to interact with biological targets. With significant attention historically expended on the synthesis of flat-heterocyclic compound libraries, methods to access the less-explored three-dimensional medicinal-chemical space will continue to increase in demand. Herein, we highlight by reaction class the common strategies used to construct the spirocyclic centres embedded in a series of well-studied natural products.1 Introduction2 Cycloadditions3 Palladium-Catalysed Coupling Reactions4 Conjugate Additions5 Imines, Aminals, and Hemiaminal Ethers6 Mannich-Type Reactions7 Oxidative Dearomatisation8 Alkylation9 Organometallic Additions10 Conclusions

scholarly journals Crystal structure of a new monoclinic polymorph ofN-(4-methylphenyl)-3-nitropyridin-2-amine

2014 ◽  
Vol 70 (8) ◽  
pp. 58-61
Author(s):  
Aina Mardia Akhmad Aznan ◽  
Zanariah Abdullah ◽  
Vannajan Sanghiran Lee ◽  
Edward R. T. Tiekink
Keyword(s):  
Three Dimensional ◽  
Basis Set ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Acta Cryst ◽  
Common Features ◽  
Compound C ◽  
B3lyp Level ◽  
The Common ◽  
Independent Molecules

The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, withZ′ = 4) of the previously reported monoclinic (P21/c, withZ′ = 2) form [Akhmad Aznanet al.(2010).Acta Cryst.E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of asyndisposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19) to 26.24 (19)°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p) basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2)–3.916 (2) Å].

The crystal structure of myoglobin. VI. Seal myoglobin

1960 ◽  
Vol 258 (1293) ◽  
pp. 181-201 ◽  
Keyword(s):  
Tertiary Structure ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Sperm Whale ◽  
Fourier Synthesis ◽  
Heavy Atoms ◽  
Isomorphous Replacement ◽  
Unit Cells ◽  
The Common ◽  
Sperm Whale Myoglobin

Myoglobin from the common seal ( Phoca vitulina ) when crystallized from ammonium sulphate forms monoclinic crystals with space group the unit cell, a = 57·9Å, b = 29·6Å, c = 106·4Å, β = 102°15', contains four molecules. The method of isomorphous replacement has been used in an investigation of the centrosymmetric b -axis projection in which it has been possible to determine signs for nearly all the h0l reflexions having spacings greater than 4Å. Three independent heavy-atom derivatives were employed and the signs so determined have been used to compute a map of the electron density projected on the (010) plane. This projection has been interpreted in terms of the molecule of sperm-whale myoglobin, as deduced by Bodo, Dintzis, Kendrew & Wyckoff (1959) from a three-dimensional Fourier synthesis to 6Å resolution. The results of the interpretation show that the two myoglobin molecules are very similar in form (tertiary structure) in spite of the differences in their amino-acid composition. The relative orientation of the two unit cells with respect to the myoglobin molecule is given and a comparison is made of the positions of the heavy atoms in each molecule.

Mechanism Design and Kinematics Simulation of Massage Mechanical Arm

2011 ◽  
Vol 101-102 ◽  
pp. 279-282 ◽  
Author(s):  
Jun Xie ◽  
Jun Zhang ◽  
Jie Li
Keyword(s):  
Mechanism Design ◽  
Three Dimensional ◽  
Forward Kinematics ◽  
Kinematics Analysis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Kinematics Model ◽  
Kinematics Simulation ◽  
The Common ◽  
Executive Mechanism

Based on the characteristics and the common massage manipulations of Chinese medical massage, a practical series mechanical arm was presented to act the manipulations with the parallel executive mechanism. Forward kinematics was solved by the Denavit-Hartenberg transformation after the kinematics model of the arm was established. And the three-dimensional model of the arm was created by Pro/E and was imported into ADAMS for the kinematics analysis. The results indicated that the common massage manipulations could be simulated by the arm correctly and flexibly, and it verified the accuracy of the mechanism design of the arm.

Trajectory planning for coordinately operating robots

1990 ◽  
Vol 4 (3) ◽  
pp. 165-177 ◽  
Author(s):  
Y. P. Chien ◽  
Qing Xue
Keyword(s):  
Trajectory Planning ◽  
Three Dimensional ◽  
Initial Position ◽  
Minimum Time ◽  
Future Research ◽  
Rigid Object ◽  
Redundant Robots ◽  
Planning Algorithm ◽  
The Common ◽  
Joint Velocity

An efficient locally minimum-time trajectory planning algorithm for coordinately operating multiple robots is introduced. The task of the robots is to carry a common rigid object from an initial position to a final position along a given path in three-dimensional workspace in minimum time. The number of robots in the system is arbitrary. In the proposed algorithm, the desired motion of the common object carried by the robots is used as the key to planning of the trajectories of all the non-redundant robots involved. The search method is used in the trajectory planning. The planned robot trajectories satisfy the joint velocity, acceleration and torque constraints as well as the path constraints. The other constraints such as collision-free constraints, can be easily incorporated into the trajectory planning in future research.

Regulation of cell proliferation patterns by homeotic genes during Arabidopsis floral development

Development ◽  
2000 ◽  
Vol 127 (6) ◽  
pp. 1267-1276 ◽  
Author(s):  
P.D. Jenik ◽  
V.F. Irish
Keyword(s):  
Cell Proliferation ◽  
Apical Meristem ◽  
Floral Development ◽  
Developmental Process ◽  
Cell Layer ◽  
Homeotic Genes ◽  
Transmitting Tract ◽  
Organ Identity ◽  
Element System ◽  
Cell Layers

The shoot apical meristem of Arabidopsis thaliana consists of three cell layers that proliferate to give rise to the aerial organs of the plant. By labeling cells in each layer using an Ac-based transposable element system, we mapped their contributions to the floral organs, as well as determined the degree of plasticity in this developmental process. We found that each cell layer proliferates to give rise to predictable derivatives: the L1 contributes to the epidermis, the stigma, part of the transmitting tract and the integument of the ovules, while the L2 and L3 contribute, to different degrees, to the mesophyll and other internal tissues. In order to test the roles of the floral homeotic genes in regulating these patterns of cell proliferation, we carried out similar clonal analyses in apetala3-3 and agamous-1 mutant plants. Our results suggest that cell division patterns are regulated differently at different stages of floral development. In early floral stages, the pattern of cell divisions is dependent on position in the floral meristem, and not on future organ identity. Later, during organogenesis, the layer contributions to the organs are controlled by the homeotic genes. We also show that AGAMOUS is required to maintain the layered structure of the meristem prior to organ initiation, as well as having a non-autonomous role in the regulation of the layer contributions to the petals.

A fate map of the Arabidopsis embryonic shoot apical meristem

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 745-753 ◽  
Author(s):  
V. F. Irish ◽  
I. M. Sussex
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Histological Analysis ◽  
Cell Number ◽  
Leaf Primordia ◽  
Axillary Buds ◽  
Fate Map ◽  
Seed Embryo ◽  
Sector Analysis ◽  
Pale Green

We have mapped the fate of cells in the Arabidopsis embryonic shoot apical meristem by irradiating seed and scoring the resulting clonally derived sectors. 176 white, yellow, pale green or variegated sectors were identified and scored for their position and extent in the resulting plants. Most sectors were confined to a fraction of a leaf, and only occasionally extended into the inflorescence. Sectors that extended into the inflorescence were larger, and usually encompassed about a third to a half of the inflorescence circumference. We also find that axillary buds in Arabidopsis are clonally related to the subtending leaf. Sections through the dry seed embryo indicate that the embryonic shoot apical meristem contains approximately 110 cells in the three meristematic layers prior to the formation of the first two leaf primordia. The histological analysis of cell number in the shoot apical meristem, in combination with the sector analysis have been used to construct a map of the probable fate of cells in the embryonic shoot apical meristem.

scholarly journals Fast and Robust Orientation of Cryo-Electron Microscopy Images

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Guoliang Xu ◽  
Xia Wang ◽  
Ming Li ◽  
Zhucui Jing
Keyword(s):  
Sparse Matrix ◽  
Three Dimensional ◽  
Image Plane ◽  
Real Space ◽  
Computation Method ◽  
Common Line ◽  
The Matrix ◽  
Common Lines ◽  
The Common ◽  
Dimensional Object

AbstractWe present an efficient and reliable algorithm for determining the orientations of noisy images obtained fromprojections of a three-dimensional object. Based on the linear relationship among the common line vectors in one image plane, we construct a sparse matrix, and show that the coordinates of the common line vectors are the eigenvectors of the matrix with respect to the eigenvalue 1. The projection directions and in-plane rotation angles can be determined fromthese coordinates. A robust computation method of common lines in the real space using aweighted cross-correlation function is proposed to increase the robustness of the algorithm against the noise. A small number of good leading images, which have the maximal dissimilarity, are used to increase the reliability of orientations and improve the efficiency for determining the orientations of all the images. Numerical experiments show that the proposed algorithm is effective and efficient.

Vertical Disparity Can Alter Perceived Direction

Perception ◽  
10.1068/p3440 ◽  
2002 ◽  
Vol 31 (11) ◽  
pp. 1323-1333 ◽  
Author(s):  
Ellen M Berends ◽  
Raymond van Ee ◽  
Casper J Erkelens
Keyword(s):  
Three Dimensional ◽  
Visual Scene ◽  
Eye Position ◽  
Vertical Disparity ◽  
Vertical Scale ◽  
The Common ◽  
The Right ◽  
The Relationship ◽  
Straight Ahead ◽  
Stimulus Direction

It has been well established that vertical disparity is involved in perception of the three-dimensional layout of a visual scene. The goal of this paper was to examine whether vertical disparities can alter perceived direction. We dissociated the common relationship between vertical disparity and the stimulus direction by applying a vertical magnification to the image presented to one eye. We used a staircase paradigm to measure whether perceived straight-ahead depended on the amount of vertical magnification in the stimulus. Subjects judged whether a test dot was flashed to either the left or the right side of straight-ahead. We found that perceived straight-ahead did indeed depend on the amount of vertical magnification but only after subjects adapted (for 5 min) to vertical scale (and only in five out of nine subjects). We argue that vertical disparity is a factor in the calibration of the relationship between eye-position signals and perceived direction.

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