Wheat embryo ribonucleates. VI. Comparison of the 3′-hydroxyl termini in 'rapidly labelled' RNA from metabolizing wheat embryos with the corresponding termini in ribosomal RNA from differentiating embryos of wheat, barley, corn and pea

1976 ◽  
Vol 54 (3) ◽  
pp. 261-271 ◽  
Author(s):  
K. M. Oakden ◽  
B. G. Lane

The NaCl-insoluble (2.5 M, 0 °C) fraction of wheat embryo RNA (iRNA) can be labelled when wheat embryos are subjected to either short-term (0.5 h) or long-term (24 h) imbibition in a medium that contains tritium-labelled adenosine, guanosine, cytidine and uridine. Electrophoretic analyses reveal that, after short-term labelling, there is a broadly heterodisperse distribution of radioactivity in 'rapidly labelled' i[3H]RNA, but after long-term labelling, there is an essentially trimodal distribution of radioactivity in i[3H]RNA. End-group analyses reveal that, after short-term labelling, adenosine is the principal 3′-hydroxyl terminus in all centrifugal subfractions of 'rapidly labelled' i[3H]RNA, whereas cytidine (in 5.8S rRNA), guanosine (in 18S rRNA) and uridine (in 26S rRNA) are the principal 3′-hydroxyl termini in centrifugal subfractions of wheat embryo i[3H]RNA. Guanosine is also the principal 3′-hydroxyl terminus in the 18S rRNA of differentiating embryos excized from both monocotyledonous (wheat, barley, corn) and dicotyledonous (pea) seedlings. The implications that the end-group measurements may have for current views about the possible biochemical involvements of 3′-hydroxyl terminal sequences in both mRNA and 18S rRNA are subjects of discussion. Incidental to the principal investigation, an existing technique for analyzing the RNA contents of cellular materials has been appropriately modified to circumvent interference from uv-absorbing pigments, which, when present, prevent application of the method to plant materials.

1977 ◽  
Vol 55 (5) ◽  
pp. 582-586 ◽  
Author(s):  
M. W. Gray ◽  
R. S. Cunningham

Two hypermodified, alkali-stable dinucleotide sequences, each containing abase modification in addition to sugar methylation, are known to be present in wheat embryo 26S + 18S rRNA (Gray, M. W. (1974) Biochemistry 13, 5453–5463). Quantitative analysis of unfractionated 26S + 18S rRNA had suggested that each of these sequences (Cm-ψp and ψm-Ap, where Cm = O2′-methylcytidine and ψm = O2′-methylpseudouridine) was present in either the 18S or the 26S rRNA species, but not in both, at a frequency of not more than once per chain. In the study reported here, the individual 32P-labeled 18S and 26S rRNA species were isolated from viable wheat embryos germinated in the presence of [32P]orthophosphate. From analyses of phosphodiesterase and alkaline hydrolysates of the separated [32P]RNAs, we conclude that ψm-Ap is confined to wheat cytosol 18S rRNA, whereas Cm-ψp is localized in wheat cytosol 26S rRNA. The presence of ψm in the 18S rRNA of wheat stands in contrast with the situation in animal cells, where this hypermodified nucleoside is located in the 28S rRNA (Khan, M. S. N. &Maden, B. E. H. (1976) J. Mol. Biol. 101, 235–254)


1975 ◽  
Vol 53 (3) ◽  
pp. 320-327 ◽  
Author(s):  
A. A. Azad ◽  
B. G. Lane

Under the conditions used in this study, wheat-embryo 5S rRNA complexes with its homologous 18S rRNA from wheat embryos and with heterologous 18S rRNA from other eukaryotic source materials such as yeast, L cells, and HeLa cells, but it does not complex with heterologous 16S rRNA from a prokaryote such as Escherichia coli or with homologous or heterologous 26S(23S) rRNA of either eukaryotic or prokaryotic origin.If a solution of wheat-embryo rRNA is simply made 0.3 M with respect to NaCl and then heated at 60 °C for 3 min before quick cooling to room temperature (ca. 20 °C), there is both preferential and efficient complex formation between 5S and 18S rRNA and between 5.8S and 26S rRNA.The laboratory-prepared' complex between wheat-embryo 5S rRNA and its homologous 18S rRNA is more thermostable in 0.1 M NaCl solution than is the 'natural' complex between wheat-embryo 5.8S rRNA and its homologous 26S rRNA, and both complexes 'melt' over a narrow range of temperature.The possible physicochemical and physiological importance of both homologous and heterologous rRNA complexes is the subject of a brief discussion.


1978 ◽  
Vol 56 (3) ◽  
pp. 197-202 ◽  
Author(s):  
T. D. Kennedy ◽  
B. G. Lane

There are conserved complements of ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA) in dry wheat embryos. Although early labelling of RNA is largely directed toward the synthesis of complete molecules of nascent rRNA and mRNA, there is also selective labelling at 3′-hydroxyl termini in conserved polynucleotides when dry wheat embryos are subjected to short-term (0.5 h) imbibition in a medium that contains tritium-labelled adenosine, guanosine, cytidine, and uridine. Conserved tRNA is the principal mass component in NaCl-soluble RNA (sRNA) and most of the 'rapid labelling' of sRNA (rl-sRNA) is a result of labelling at 3′-hydroxyl termini in conserved tRNA. By contrast, although conserved rRNA is the principal mass component in NaCl-insoluble RNA (iRNA), most of the labelled 3′-hydroxyl termini in 'rapidly labelled' iRNA (rl-iRNA) do not appear to derive from rRNA. Although about 10% of the labelled 3′-hydroxyl termini in rl-iRNA originates in conserved poly(A)-rich mRNA, the available evidence leads to the conclusion that most of the labelled 3′-hydroxyl termini in rl-iRNA originates in an unusual NaCl-insoluble fraction of conserved tRNA. During the course of extended imbibition, between 0.5 and 5 h, there are characteristic changes in the chain lengths and labelling patterns for 3′-hydroxyl terminal poly(A) sequences in mRNA. Analytical and physiological implications of these data are subjects of discussion.


1977 ◽  
Vol 55 (1) ◽  
pp. 99-109 ◽  
Author(s):  
K. M. Oakden ◽  
A. A. Azad ◽  
B. G. Lane

(1) If wheat embryo 5S and 5.8S rRNA are differentially labelled, it can be shown that there is highly selective association of 5S [14C]RNA with 18S rRNA, and of 5.8S [3H]RNA with 26S rRNA when a solution (0.3 M NaCl) that contains approximately equimolar amounts of the four ribosomal polynucleotides is heated briefly (3 min) at 60 °C.(2) Comparison of Tm values and melting profiles for laboratory-prepared and natural 5.8S–26S rRNA hybrids suggests that restoration of the natural union between 5.8S and 26S rRNA can be achieved with facility and fidelity in the laboratory.(3) Union between 5.8S and 26S rRNA remains intact when wheat embryo ribosomes are disintegrated either by digestion with pronase or by treatment with sodium dodecyl sulphate, but the same treatments release 5S and 18S rRNA as freely migrating electrophoretic components.(4) Intact 18S and 26S rRNA can be prepared from small and large subunits, respectively, when wheat embryo ribosomes are dissociated by treatment with 0.5 M KCl.(5) Incidental to the principal investigation, it has been shown that, even after storage for more than 6 years at − 70 °C, commercial supplies of roller-milled wheat germ yield S23 extracts that are very active in the cell-free translation of globin mRNA.(6) The physicochemical and possible biochemical significance of various types of intermolecular complexing between pairs of ribosomal polynucleotides is a subject of discussion.


2021 ◽  
Vol 10 (6) ◽  
pp. 263-269
Author(s):  
Natalia Schäfer ◽  
◽  
Radosław Balwierz ◽  
Anna Krzeszewska-Zaręba ◽  
Zbigniew Skotnicki ◽  
...  

The cosmetic market is rich in products that allow changing the color of hair. There are three options for chemical coloring, depending on the duration of the target color. Among them, there are short-term, semi-permanent, and long-term dyeing. Using synthetic ingredients, it is possible to obtain a full range of colors. Reports of undesirable side effects of chemical dyes on both the scalp and hair structure support a return to natural hair coloration and a development in this direction. The aim of the work was to draw attention to apply botanical raw materials in hair dyeing. The work presents the characteristics of the following plant materials used in hair dyeing: defenseless lawsonia, oxalic hibiscus, rhubarb, elderberry and chamomile.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.


2020 ◽  
Vol 29 (4) ◽  
pp. 710-727
Author(s):  
Beula M. Magimairaj ◽  
Naveen K. Nagaraj ◽  
Alexander V. Sergeev ◽  
Natalie J. Benafield

Objectives School-age children with and without parent-reported listening difficulties (LiD) were compared on auditory processing, language, memory, and attention abilities. The objective was to extend what is known so far in the literature about children with LiD by using multiple measures and selective novel measures across the above areas. Design Twenty-six children who were reported by their parents as having LiD and 26 age-matched typically developing children completed clinical tests of auditory processing and multiple measures of language, attention, and memory. All children had normal-range pure-tone hearing thresholds bilaterally. Group differences were examined. Results In addition to significantly poorer speech-perception-in-noise scores, children with LiD had reduced speed and accuracy of word retrieval from long-term memory, poorer short-term memory, sentence recall, and inferencing ability. Statistically significant group differences were of moderate effect size; however, standard test scores of children with LiD were not clinically poor. No statistically significant group differences were observed in attention, working memory capacity, vocabulary, and nonverbal IQ. Conclusions Mild signal-to-noise ratio loss, as reflected by the group mean of children with LiD, supported the children's functional listening problems. In addition, children's relative weakness in select areas of language performance, short-term memory, and long-term memory lexical retrieval speed and accuracy added to previous research on evidence-based areas that need to be evaluated in children with LiD who almost always have heterogenous profiles. Importantly, the functional difficulties faced by children with LiD in relation to their test results indicated, to some extent, that commonly used assessments may not be adequately capturing the children's listening challenges. Supplemental Material https://doi.org/10.23641/asha.12808607


2019 ◽  
Vol 25 ◽  
pp. 114
Author(s):  
Alyssa Dufour ◽  
Setareh Williams ◽  
Richard Weiss ◽  
Elizabeth Samelson

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