The complexometric determination of zinc in the presence of large quantities of magnesium

Brown, Eric G.; Hayes, Tim

doi:10.1016/s0003-2670(01)80794-7

Cited by 51 publications

(58 citation statements)

References 6 publications

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“…Digestion of cellulose from alfalfa was determined by using the Crampton-Maynard procedure (17). Glucose utilization was determined colorimetrically at 520 m with the orcinol reaction (14).…”

Section: Methodsmentioning

confidence: 99%

Antibiosis between Ruminal Bacteria and Ruminal Fungi

Dehority

Tirabasso

2000

Appl Environ Microbiol

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Cellulose digestion, bacterial numbers, and fungal numbers were monitored over time in vitro by using a purified cellulose medium with and without antibiotics (penicillin and streptomycin). All fermentations were inoculated with a 1:10 dilution of whole rumen contents (WRC). Without antibiotics, cellulose digestion was higher (P < 0.01) at 24, 30, 48, and 72 h; fungi had almost disappeared by 24 h, while bacterial concentrations increased over 100-fold in 24 h and then decreased gradually up to 72 h. In those fermentations with added antibiotics, fungal concentrations increased 4-fold by 30 h and up to 42-fold at 72 h; bacterial concentrations were markedly reduced by 24 h and remained low through 72 h. Similar results were obtained with ground alfalfa as a substrate. In further studies, the in vitro fermentation of purified cellulose without antibiotics was stopped after 18 to 20 h, and the microbial population was killed by autoclaving. Antibiotics were added to half of the tubes, and all tubes were reinoculated with WRC. After 72 h, extensive cellulose digestion had occurred in those tubes without antibiotics, as compared to very low cellulose digestion with added antibiotics. The extent of this inhibition was found to increase in proportion to the length of the initial fermentation period, suggesting the production of a heat-stable inhibitory factor or factors. The inhibitory activity was present in rumen fluid, could be extracted from lyophilized rumen fluid (LRF) with water, and was stable in response to proteolytic enzymes. In addition, the water-extracted residue of LRF was found to contain growth factor activity for rumen fungi in vitro.The flagellated microorganisms observed in rumen contents by Liebetanz in 1910 (36) and Braune in 1913 (13) were originally believed to be flagellate protozoa. However, in a series of classic studies, Orpin (39-45) determined that these organisms were actually flagellated zoospores of anaerobic fungi. Although concentrations of the fungi are relatively low in comparison to those of the bacteria and ciliate protozoa, they possess a wide range of enzymes which are capable of hydrolyzing most of the structural polysaccharides occurring in plant cell walls (21,26,35,48,53,55). The fungi also appear to be superior to the rumen bacteria in their ability to break down and degrade the structural barriers in plant material (2). They are able to weaken and partially or fully degrade the more recalcitrant plant tissues as well as penetrate the cuticle barrier (3, 5, 34). When fungi were removed from the rumen, both feed intake and fiber digestibility were decreased; however, total viable bacteria, cellulolytic bacteria, or ciliate protozoal concentrations were not affected (24). Based on in vitro studies with rumen fluid, using antibiotics and a fungicide to selectively culture either the bacteria or fungi, Akin and coworkers (1, 56) concluded that the bacteria were the most active fiberdigesting organisms, even though fungal numbers were increased in the antibiotic-treated cultur...

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Section: Methodsmentioning

confidence: 99%

Antibiosis between Ruminal Bacteria and Ruminal Fungi

Dehority

Tirabasso

2000

Appl Environ Microbiol

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“…Protein assay was made by Lowry's method [17]. Qualitative and quantitative assays for sugars, amino acids, and uronic acids were made by various color reactions such as the anthrone reaction [20], the carbazole reaction [7], the orcinol reaction [2], the phenol-sulfuric acid Please address requests of reprints to Dr. Takeo Murakawa, Department of Microbiology, Toho University School of Medicine, 5-21-16 Omori-nishi, Ohta-ku, Tokyo 143, Japan. 513 method [8], the diphenylamint method [4], the naphthoresorcinol reaction [22] and the Molish reaction.…”

Section: Methodsmentioning

confidence: 99%

Slime Production by Pseudomonas aeruginosa

Murakawa

1973

Japanese Journal of Microbiology

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Chemical properties and compositions of slimes produced by two Pseudomonas aeruginosa strains of different colonial types were investigated. The main component of the slime from strain IFO 3445 was found to be DNA, contaminated with small amounts of protein. On the other hand, the slime from a mucoid‐type strain No. 24 was an alginate‐like substance consisting of mannuronic and glucuronic acids, and contained traces of protein and nucleic acid. Slimes from twenty clinical isolates of P. aeruginosa were investigated for their chemical compositions. Slimes from eighteen strains consisted of DNA, while, two strains of a mucoid‐type produced slimes composed of polyuronic acid.

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“…The concentrations of DNA and RNA were determined by the diphenylamine and orcinol methods, respectively (14,15 The nuclear pellet was subjected to phase microscopy to ensure that it was free of significant cytoplasmic strands. Once isolated, the cytoplasmic fraction was precipitated with 3 vol of absolute ethanol.…”

Section: Animal Studiesmentioning

confidence: 99%