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J B Lowry

Publications and source records attributed to J B Lowry.

10 recordsLinked to original sources
PubMed1999

An acetylxylan esterase and a xylanase expressed from genes cloned from the ruminal fungus Neocallimastix patriciarum act synergistically to degrade acetylated xylans.

A Neocallimastit patriciarum acetylxylan esterase (BnaA) was expressed from the cloned gene in Escherichia coli. Purified recombinant BnaA efficiently released acetate from soluble acetylated birchwood xylan (ABX), with a specific activity of 76 U mg-1. In contrast, release of acetate was very inefficient from the insoluble substrates, spear grass and delignified spear grass. Addition of a recombinant xylanase, XynA, also expressed from a cloned N. patriciarum gene, had no effect on the release of acetate from ABX. However, the combination of recombinant BnaA and XynA released more acetate from spear grass and delignified spear grass than did BnaA alone. Significantly more reducing sugar was also released from all three substrates by the combination of recombinant XynA and BnaA than by XynA alone. Thus the extent of digestion of acetylated xylans by XynA appears to be limited by the acetylation. In this system BnaA does not appear to increase the rate of cleavage of insoluble substrates by XynA, but probably allows the release of shorter xylose oligomers from already solubilised acetylated xylan polymers.

Acetates↗
PubMed1994

Solubilization of lignin by the ruminal anaerobic fungus Neocallimastix patriciarum.

The ability of the ruminal anaerobic phycomycete Neocallimastix patriciarum to digest model lignin compounds and lignified structures in plant material was studied in batch culture. The fungus did not degrade or transform model lignin compounds that were representative of the predominant intermonomer linkages in lignin, nor did it solubilize acid detergent lignin that had been isolated from spear grass. In a stem fraction of sorghum, 33.6% of lignin was apparently solubilized by the fungus. Solubilization of ester- and either-linked phenolics accounted for 9.2% of the lignin released. The amounts of free phenolic acids detected in culture fluid were equivalent to the apparent loss of ester-linked phenolics from the sorghum substrate. However, the fungus was unable to cleave the ether bond in hydroxycinnamic acid bridges that cross-link lignin and polysaccharide. It is suggested that the majority of the solubilized lignin fraction was a lignin carbohydrate complex containing ether-linked hydroxycinnamic acids. The lignin carbohydrate complex was probably solubilized through dissolution of xylan in the lignin-xylan matrix rather than by lignin depolymerization.

Anaerobiosis↗
PubMed1991

Complexing of toxic hydrolysable tannins of yellow-wood (Terminalia oblongata) and harendong (Clidemia hirta) with reactive substances: an approach to preventing toxicity.

Ruminants consuming either tannic acid or hydrolysable tannins from the Australian yellow-wood tree (Terminalia oblongata) and the Indonesian shrub Clidemia hirta are intoxicated by simple phenolics liberated in the gut. The affinity of these tannins and of the simple phenolic gallic acid for the two proteins casein and pepsin, polyvinylpyrolidone (PVP), activated charcoal and Ca(OH)2 was examined in vitro. The studies were undertaken to predict the effect of these phenolics on digestion and to identify substances that would act as antidotes by precipitating phenolics. Tannins but not gallic acid were precipitated as stable complexes with both pepsin and casein at pH 3-5. Optimal complexing of tannin with protein occurred at a weight ratio of 1:1. Ionic strength and temperature did not affect the amount of tannin precipitated from solution with protein. The precipitation of tannins with PVP and Ca(OH)2 was unaffected by pH within the range 2-8 while maximum binding with activated charcoal occurred between pH 3 and 7. In contrast to protein, the other substances complexed with gallic acid; only gallic acid-PVP complexes were affected by pH. Calcium hydroxide bound more tannin and gallic acid on a weight basis than PVP and charcoal. Both Ca(OH)2 and activated charcoal should complex with phenolics in the forestomach, abomasum and intestines. The reaction of hydrolysable tannins and proteins at the pH found in the abomasum suggests that hydrolysable tannins would interfere with enzyme function and protein digestion post-ruminally rather than in the forestomach.

Animals↗
PubMed1988

Is incidental appendectomy a safe practice?

In an attempt to determine the safety of appendectomy performed as an incidental procedure, the authors reviewed 853 operations (458 hysterectomies and 395 cholecystectomies) performed by five surgeons at one hospital between 1981 and 1984 and compared the results in 35% of the patients who underwent incidental appendectomy with those in the remainder. Factors studied were operative time, postoperative stay, postoperative fever and leukocytosis, the need for intravenous fluids, parenteral analgesia and antibiotics, and infectious complications. Most of these variables differed between individual surgeons, but the addition of incidental appendectomy did not significantly alter any variable for an individual surgeon or for the group as a whole. Incidental appendectomy seems to be a safe practice and one that does not alter the outcome of hysterectomy or cholecystectomy but does protect against subsequent appendicitis.

Appendectomy↗
PubMed1985

Fatal, overwhelming sepsis after splenectomy in the community hospital.

Charts of all patients who underwent splenectomy between 1965 and 1981 at the Orillia Soldiers' Memorial Hospital were reviewed. At the end of 1983, the patient, relatives or family physician were contacted for follow-up. Eighty spleens were removed, 36 for medical reasons, 30 for trauma and 14 because of iatrogenic injury. Of the patients followed up, 51 were alive and 13 had died. Three died in the postoperative period and seven died of unrelated causes. Three patients died of overwhelming sepsis, 1, 3 and 7 years after splenectomy. If the three postoperative deaths are excluded and it is assumed none of the 16 untraced patients died of overwhelming sepsis, the incidence of death from this cause was 3.9%.

Acute Disease↗
PubMed1984

Australian goats detoxify the goitrogen 3-hydroxy-4(1H) pyridone (DHP) after rumen infusion from an Indonesian goat.

The failure of Australian goats fed Leucaena leucocephala (leucaena) to degrade 3-hydroxy-4(1H) pyridone (DHP), the goitrogenic metabolite of mimosine, was overcome when they were infused with rumen fluid from an Indonesian goat. The leucaena toxicity problem in Australia may well be solved by transfer of specific bacteria capable of degrading DHP anaerobically.

Animal Feed↗
PubMed1979

Direct spectorphotometric assay of quaternary ammonium compounds using bromthymol blue.

Benzalkonium chloride, benzethonium chloride, and chlorhexidine gluconate were assayed quantitatively by a direct spectrophotometric method with bromthymol blue buffered at pH 7.5. The method shows good results at concentrations of 0--300 microgram/ml and in the presence of epinephrine bitartrate, phenylephrine hydrochloride, pilocarpine hydrochloride, and polyvinyl alcohol.

Benzalkonium Compounds↗