Formation of Nucellar Embryos with Total Absence of Embryo Sacs in Two Species of Gramineae

1977 ◽  
Vol 41 (2) ◽  
pp. 469-470 ◽  
Author(s):  
C. SHANTHAMMA ◽  
K. N. NARAYAN
Author(s):  
R. C. Moretz ◽  
D. F. Parsons

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.


2021 ◽  
Vol 112 (1) ◽  
pp. 52-68
Author(s):  
Juan Chapa
Keyword(s):  

Abstract Within the NT, the expression ἐν παντὶ τόπῳ is found only in the Pauline corpus (1Cor 1,2; 2Cor 2,14; 1Thess 1,8; 1Tim 2,8). In 1Cor 1,2, traditionally the phrase has been considered as having an adverbial sense. However, the presence of the specific adverb πανταχοῦ for conveying the same meaning in 4,17 might point to some intentionality in the use of ἐν παντὶ τόπῳ in the initial greetings and not only to preferences of style. The almost total absence of the expression ἐν παντὶ τόπῳ in extrabiblical Greek against a well-attested presence in the OT Greek as a translation of בכל־מקום, suggests that in 1Cor 1,2 the phrase is a Semitism that echoes a cultic OT usage.


1992 ◽  
Vol 47 (5-6) ◽  
pp. 341-345 ◽  
Author(s):  
Gerhard Veen ◽  
Roland Greinwald ◽  
Paloma Cantó ◽  
Ludger Witte ◽  
F.-C. Czygan

Alkaloid extracts from different organs of Adenocarpus hispanicus ssp. hispanicus and Adenocarpus hispanicus ssp. gredensis were analyzed by capillary GC. Twenty-four compounds could be identified by the high sensitive method of GLC-MS: the pyrrolizidine alkaloids decorticasine, N-acetylnorloline and N-butyrylnorloline, the bipiperidyl alkaloid ammodendrine, the phenylethylamine tyramine and 19 quinolizidine alkaloids. In contrast to Adenocarpus complicatus, Adenocarpus foliolosus and Adenocarpus viscosus the alkaloid pattern of Adenocarpus hispanicus is characterized by the occurrence of quinolizidine alkaloids with sparteine predominating in the leaves and numerous dehydroderivatives of sparteine. Remarkable is the total absence of adenocarpine which was described as a main compound of the three former species. Our results strongly support the opinion that the genus Adenocarpus should be divided into two phytochemical groups.


1989 ◽  
Vol 67 (11) ◽  
pp. 3219-3226 ◽  
Author(s):  
Bernard R. Baum ◽  
A. Pat Tulloch ◽  
L. Grant Bailey

This study was based on 148 accessions representing 39 species of Hordeum. SEM ultrastructural morphology of waxes was based on individual spikelets, whereas waxes' chemical composition was assessed from whole plants. When all the data, in the form of individual accessions, were subjected to various cluster analyses methods, no groupings were revealed. But when the data were first summarized by species and then subjected to clustering, two polythetic groups of species were detected. Group 1 is characterized by species with 40–60% average alcohol content and by the common presence of diketones, whereas group 2 is characterized by species with 61 – 80% average alcohol content, by the total absence of hydroxy-β-diketone, and almost all species without β-diketone. The chemical data were then subjected to classificatory discriminant analysis to assess if a single previously unclassified accession could be identified into one of the two groupings. The nature of the differences between the two groupings was described by means of a canonical discriminant analysis. Mostly only plates and filaments were detected, and in many accessions the filaments were widened, appeared platelike, and were characteristic for one group. Presence of β-diketone varied within species. Hordeum violaceum was found to be unique in chemical composition.


2014 ◽  
Vol 64 (5) ◽  
pp. 286-289 ◽  
Author(s):  
Ato Sugiyama ◽  
Yotaro Izumi ◽  
Yoshiaki Inoue ◽  
Kohei Aoki ◽  
Hiroki Fukuda ◽  
...  

2011 ◽  
Vol 440 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Alejandro Martín-Montalvo ◽  
Isabel González-Mariscal ◽  
Sergio Padilla ◽  
Manuel Ballesteros ◽  
David L. Brautigan ◽  
...  

CoQ6 (coenzyme Q6) biosynthesis in yeast is a well-regulated process that requires the final conversion of the late intermediate DMQ6 (demethoxy-CoQ6) into CoQ6 in order to support respiratory metabolism in yeast. The gene CAT5/COQ7 encodes the Cat5/Coq7 protein that catalyses the hydroxylation step of DMQ6 conversion into CoQ6. In the present study, we demonstrated that yeast Coq7 recombinant protein purified in bacteria can be phosphorylated in vitro using commercial PKA (protein kinase A) or PKC (protein kinase C) at the predicted amino acids Ser20, Ser28 and Thr32. The total absence of phosphorylation in a Coq7p version containing alanine instead of these phospho-amino acids, the high extent of phosphorylation produced and the saturated conditions maintained in the phosphorylation assay indicate that probably no other putative amino acids are phosphorylated in Coq7p. Results from in vitro assays have been corroborated using phosphorylation assays performed in purified mitochondria without external or commercial kinases. Coq7p remains phosphorylated in fermentative conditions and becomes dephosphorylated when respiratory metabolism is induced. The substitution of phosphorylated residues to alanine dramatically increases CoQ6 levels (256%). Conversely, substitution with negatively charged residues decreases CoQ6 content (57%). These modifications produced in Coq7p also alter the ratio between DMQ6 and CoQ6 itself, indicating that the Coq7p phosphorylation state is a regulatory mechanism for CoQ6 synthesis.


Author(s):  
Sindiwe Magona

Sindiwe Magona started writing in pursuit of agency as opposed to victimhood. With no training in writing, she felt nonetheless she could paint a much better, more realistic picture than what she found in stories of her people written by white people, to say nothing of how history books represented black Africans or “Bantu” as the terminology of the day went. Another fact that pushed her to dare to write was the almost total absence of records left to her generation by the preceding one. She wanted to close that lacuna. Her first book, To My Children’s Children, was published in 1990 when she was almost fifty years old. Magona wrote the autobiography as a record of life lived in a specific period, by specific people, using hers as an example. The book references other lives, not only that of her family. The cultural milieu and the overarching theme, given the times, however, is of the oppressive system of apartheid—legalized racism. Memory represents not only what is remembered but the inescapable past as represented by the still felt, still visible, still “performing” insights, ideas, ideology, actions, and reactions of South Africans almost a quarter of a century since the end of apartheid came with the first democratic elections of April 27, 1994. Each of her books—four novels, two collections of short stories, two autobiographies, two published plays, three biographies, a book of poetry, as well as her articles, essays, and talks—gives evidence of Magona’s witness of what happens, how it happens, and its observed or acknowledged consequences. She takes the journey further, exploring the inner meanings of the observed. The inner lives of victims and perpetrators, of oppressed and oppressor, and all the other binaries of which she is aware concern her. She set out to write, to leave a record for all posterity, not only black posterity, for it is her firm belief, hope, and prayer that, ere long, humanity will find itself, regain its former oneness or sense of belonging, and understand there are no races but one, the human race.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 121 ◽  
Author(s):  
S. Jeyalaksshmi ◽  
S. Prasanna

Grayscale is a series of shades of gray without apparent color. The total absence of transmitted or reflected light, which is the darkest shade, black. The total reflection or transmission of light at all observable wavelengths, which is nothing but lightest possible shade i.e., white. Intermediate shades of gray are characterized by equal brightness levels of the primary colors (red, green and blue) for transmitting light, or equal amounts of the three primary pigments (magenta,cyan, and yellow) for reflected light. This paper focuses mainly on measuring the properties of objects in a grayscale image using Regionprops to calculate the standard Deviation. This is achieved by segmenting a grayscale image to get objects of a binary image. Although, the common problem of including chromatic values to a grayscale image has objective solution,not exact, the present approach tries to provide an approach to help minimize the amount of human labor required for this task. We transfer the source’s whole color “mood” to the target image by matching texture information and luminance between the images rather than selecting RGB colors from a group of colors to an individual color components. We pick out to transfer only chromatic information and retain the target image’s original luminance values. Further, the procedure is improved by permitting the user to match areas of the two images with rectangular swatches. It is essential to develop grayscale image pixel value, resultant to each object in the binary image to inspect the original grayscale image.Based on the original grayscale image pixel values, the pixel value properties in grayscale image are used to do routine calculations.


Sign in / Sign up

Export Citation Format

Share Document