scholarly journals The degradation of nucleic acids in, and the removal of breakdown products from the small intestines of steers

1980 ◽  
Vol 44 (1) ◽  
pp. 99-112 ◽  
Author(s):  
A. B. McAllan

1. Nucleic acids and breakdown products were estimated in digesta taken from different sites in the small intestines of slaughtered steers given different diets. Amounts passing different sites were compared using cellulose as a non-digestible marker. The validity of this marker was checked with chromic oxide in some experiments. In other experiments, nucleic acids or derivatives were infused into the proximal duodenum of steers receiving diets of approximately equal proportions of flaked maize and hay. The amounts disappearing during passage through the small intestine were estimated using polyethylene glycol (PEG) as a non- absorbable marker.2. In the slaughter experiments the amounts of nucleic acids entering the small intestine varied with the type of diet. RNA and DNA disappeared on average, to extents of 89% and 80% respectively between the abomasum and the terminal ileum, irrespective of the diet. RNA disappearance occurred almost entirely in the proximal quarter of the small intestine, whereas that of DNA extended further along the tract.3. Nucleic acid degradation in the upper small intestine was accompanied by the transient appearance of adenosine, guanosine and pyrimidine nucleosides. These products were in greatest concentration in digesta from the first quarter of the small intestine and had generally completely disappeared by the terminal ileum.4. Of the different substances infused into the small intestine, free nucleic acids were removed to extents greater than 97%, adenine, guanine and uracil had completely disappeared, thymine and xanthine to approximately 80% and 95% and hypoxanthine and cytosine to only 51% and 48% respectively. The nucleosides adenosine and cytidine were also completely removed in the small intestine but were replaced, in part, by the catabolic products inosine plus hypoxanthine or cytosine respectively. Other nucleosides were removed to approximately half the extent of the corresponding bases.5. Serum and urine allantoin and uric acid levels were related to the amounts of purines entering the small intestines in free or bound form.

1971 ◽  
Vol 25 (1) ◽  
pp. 181-190 ◽  
Author(s):  
R. H. Smith ◽  
A. B. Mcallan

1. Concentrations of nucleic acid nitrogen and other nitrogenous constituents were estimated in digesta taken from the proximal duodenum of calves which were given, either, one of a number of stall diets or pasture. These concentrations were compared, using polyethylene glycol (PEG) as a non-absorbed marker, with corresponding concentrations in rumen fluid and ileal contents.2. There was little net change in amounts of RNA or DNA between rumen and duodenum relative to PEG, but there was a marked increase in amounts of total-N. In duodenal digesta, for any one animal given most diets, nucleic acid-N formed a fairly constant percentage (8–11 for different animals) of the total non-ammonia-N. This value was lower (by about 3) than the corresponding percentage in rumen fluid. Comparison of nucleic acid-N: total-N ratios in duodenal contents and bacteria suggested that, for these diets, about 40–55% of the non-ammonia-N in duodenal contents was of microbial origin.3. During passage of digesta between the duodenum and ileum the mean percentage disappearances of total-N, RNA and DNA were estimated to be about 67, 85 and 75 respectively. There was evidence that these values varied with the amounts of the constituents entering the duodenum.4. Ammonia was absorbed in the omasum-abomasum only when concentrations in rumen fluid were high (40 mM), but even moderate concentrations of ammonia entering the duodenum (3 mM) were efficiently absorbed (about 90%) in the small intestine.


2022 ◽  
Author(s):  
LK Metthew Lam ◽  
Jane Dobkin ◽  
Kaitlyn A. Eckart ◽  
Ian Gereg ◽  
Andrew DiSalvo ◽  
...  

Red blood cells (RBCs) demonstrate immunomodulatory capabilities through the expression of nucleic acid sensors. Little is known about bat RBCs, and no studies have examined the immune function of bat erythrocytes. Here we show that bat RBCs express the nucleic acid-sensing Toll-like receptors TLR7 and TLR9 and bind the nucleic acid ligands, single-stranded RNA, and CpG DNA. Collectively, these data suggest that, like human RBCs, bat erythrocytes possess immune function and may be reservoirs for nucleic acids. These findings provide unique insight into bat immunity and may uncover potential mechanisms by which virulent pathogens in humans are concealed in bats.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Yukiko Kamiya ◽  
Tadashi Satoh ◽  
Atsuji Kodama ◽  
Tatsuya Suzuki ◽  
Keiji Murayama ◽  
...  

Abstract Xeno nucleic acids, which are synthetic analogues of natural nucleic acids, have potential for use in nucleic acid drugs and as orthogonal genetic biopolymers and prebiotic precursors. Although few acyclic nucleic acids can stably bind to RNA and DNA, serinol nucleic acid (SNA) and L-threoninol nucleic acid (L-aTNA) stably bind to them. Here we disclose crystal structures of RNA hybridizing with SNA and with L-aTNA. The heteroduplexes show unwound right-handed helical structures. Unlike canonical A-type duplexes, the base pairs in the heteroduplexes align perpendicularly to the helical axes, and consequently helical pitches are large. The unwound helical structures originate from interactions between nucleobases and neighbouring backbones of L-aTNA and SNA through CH–O bonds. In addition, SNA and L-aTNA form a triplex structure via C:G*G parallel Hoogsteen interactions with RNA. The unique structural features of the RNA-recognizing mode of L-aTNA and SNA should prove useful in nanotechnology, biotechnology, and basic research into prebiotic chemistry.


1976 ◽  
Vol 54 (5) ◽  
pp. 500-506 ◽  
Author(s):  
Philip W. Burridge ◽  
Robin A. Woods ◽  
J. Frank Henderson

Three preparations of radioactive yeast nucleic acids were fed to mice. One was labeled predominantly in the guanine moiety, one was labeled predominantly in the adenine moiety, and in one adenine and guanine were labeled equally. Most of the nucleic acid purines produced by digestion were excreted in the urine. However, a small amount was utilized for nucleotide and nucleic acid synthesis in the mouse tissues. Small intestine, liver and skeletal muscle contained most of the purines that were retained in the tissues. Dietary nucleic acid adenine appeared to be utilized somewhat more efficiently than was dietary nucleic acid guanine.


1969 ◽  
Vol 23 (3) ◽  
pp. 671-682 ◽  
Author(s):  
A. B. Mcallan ◽  
R. H. Smith

1. Procedures, based on those of Schmidt & Thannhauser (1945) and Schneider (1945), for the extraction and estimation of nucleic acids in bovine digesta were examined in detail.2. Final methods which were suitable for routine determination of RNA and DNA were essentially as follows. Digesta samples were extracted in the cold, first with a solution of trichloroacetic acid in ethanol, then with aqueous trichloroacetic acid solution and finally with lipid solvents. The dried residue was hydrolysed with alkali, purified by passage through a Dowex resin, and the RNA, in the form of mononucleotides, determined by U.V. absorption. DNA was determined separately in hot perchloric acid extracts of the original dried residue by colorimetric estimation of the deoxyribose content.


2021 ◽  
Vol 50 (8) ◽  
pp. 5126-5164 ◽  
Author(s):  
Luke K. McKenzie ◽  
Roberto El-Khoury ◽  
James D. Thorpe ◽  
Masad J. Damha ◽  
Marcel Hollenstein

While Nature harnesses RNA and DNA to store, read and write genetic information, the inherent programmability, synthetic accessibility and wide functionality of these nucleic acids make them attractive tools for use in a vast array of applications.


2014 ◽  
Vol 50 (1-2) ◽  
pp. 39-50
Author(s):  
William V. Dashek

While changes in nucleic acid and protein levels during germination and subsequent tube elongation have been determined for a number of pollens, they have not been extensively examined for <em>in vitro</em> grown <em>Lilium longiflorum</em>, cv. `Ace' pollen. Nucleic acids and proteins were extracted with cold trichloroacetic acrid (TCA), cold-hot TCA or cold TCA and potassium hydroxide-perchloric acid (KOH-HClO<sub>4</sub>). Following extraction, RNA, DNA and total protein were assayed colorimetrically with orcinol, diphenylamine and Folin-Phenol reagents, respectively. Extraction of 500 x g supernatants with KOH-HClO<sub>4</sub>, yielded less RNA than either of the TCA-extraction procedures which gave similar nucleic acids and protein recoveries. Whereas total protein levels decreased initially and then increased during 36 h, RNA and DNA levels rose throughout the time-course. Precipitation and quaritiation of nucleic acids and protein from homogenized and soaicated 500 x g pellets resulted in time-dependent alterations in levels of macromolecules which differed from those for 500 x g supernatants. Whereas DNA and RNA levels increased and then decreased over 36 h, total protein levels remained constant for 12 h and then declined during the : next 24 h. Addition of the data obtained for 500 x g supernatants to those for 500 x g pellets revealed that total protein levels increased 2.4 times for the first 12 h and thereafter remained constant, that RNA levels increased 9.8 times for the first 12 h and then levelled off and that the DNA content rose more than 5 times over 36 h.


Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 951 ◽  
Author(s):  
Justin R. Halman ◽  
Kirill A. Afonin

The use of nucleic acids (RNA and DNA) offers a unique and multifunctional platform for numerous applications including therapeutics, diagnostics, nanodevices, and materials [...]


Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 1-4 ◽  
Author(s):  
S. S. Malhotra ◽  
J. B. Hanson

The changes in the nucleic acid metabolism were studied in plants susceptible and resistant to 4-amino-3,5,6-trichloropicolinic acid (picloram). The total RNA and DNA content of the tissue correlated inversely with the herbicide resistance; the resistant plants were low in nucleic acids, whereas sensitive plants were high. The increase in the nucleic acids of the sensitive species 24 hr after picloram treatment appeared to be associated with lower levels of ribonuclease and deoxyribonuclease. The inability of the resistant species to make more RNA may be associated with high levels of nucleases in the tissue.


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