Showing papers on "Melibiose published in 1973"

α-Galactosidase Activity of Lactobacilli

Abstract: α-Galactosidase (EC 3.2.1.22) activity was observed in cell-free extracts of Lactobacillus fermenti, L. brevis, L. buchneri, L. cellobiosis, and L. salivarius subsp. salivarius. The cultural conditions under which the enzyme activity was detected suggest that the enzyme is constitutive and present in the soluble fraction in the cell. The enzyme preparations readily hydrolyzed melibiose and other oligosaccharides containing α(1 → 6) linked galactose. Although the cell-free extracts of L. fermenti and L. brevis are negative for β-fructofuranosidase (EC 3.2.1.26), they hydrolyzed melibiose, stachyose, and raffinose in decreasing order of activity. The β-fructofuranosidase-positive L. buchneri, L. cellobiosis, and L. salivarius preparations hydrolyzed melibiose, raffinose, and stachyose in decreasing rates of activity. The α-galactosidases from different lactobacilli showed optimum activity in pH range 5.2 to 5.9. L. fermenti and L. salivarius preparations exhibited maximum activity between 40 to 44 C and 48 to 51 C, respectively, whereas a 38 to 42 C range was observed for other lactobacilli. Cell-free extract of L. cellobiosis was studied for transgalactosylase activity. When incubated with melibiose, a new compound was detected and tentatively identified as manninotriose.

The lactose system in Klebsiella aerogenes V9A 2. Galactoside permeases which accumulate lactose or melibiose

Abstract: Klebsiella aerogenes V9A possesses at least three galactoside permeases, the lactose permease (LacP), the melibiose permease (MelP) and a third permease (GPIII), and also a galactose permease. It is shown that the first three of these permeases all accumulate both lactose and melibiose efficiently, while the galactose permease takes up neither sugar. Lactose only induces LacP and melibiose only induces MelP. d -fucose, isopropyl-β- d -thiogalactoside (IPTG) and methyl-β- d -thiogalactoside (TMG) all induce GPIII, but galactose does not. GPIII takes up both lactose and melibiose but cannot accumulate lactose in the presence of IPTG. Thus substantial differences are found between the galactoside permeases of Klebsiella and Escherichia coli .

Litmus milk reaction as a distinguishing feature between streptococcus faecalis of human and non-human origins

Abstract: More than 90% of 1618 cultures of Streptococcus faecalis obtained from plants, wild animals, and insects produced a soft, reduced, rennet-like curd which underwent stratiform digestion in litmus milk, or else produced no reaction. Cultures of human origin produced a reduced, hard, acidic curd which sometimes was followed by acid-proteolytic digestion. Ten percent of the cultures commensal in nature fermented lactose in litmus milk to produce the hard, acidic curd which sometimes underwent acid-proteolytic digestion. One-third of this group of organisms failed to follow the typical pattern of fermentation by S. faecalis of human origin, that is fermentation of melezitose but not of melibiose. It is suggested that for cultures obtained during analytical procedures the reaction in litmus milk and the fermentation of melezitose and melibiose may be employed to distinguish between contamination representing recent pollution of human origin and the presence of S. faecalis as a member of the microflora of plants...

Physiological effect of sugars on various digestive enzymes ofSpodoptera littoralis larvae

Abstract: Feeding of Styropor lamellae treated with 0.25 M maltose, sucrose, raffinose or melezitose byS. littoralis larvae induced amylase activity to 5–6 fold and invertase and protease activity to 2–3 that of the control. Melibiose induced amylase activity to about 4-fold and invertase and protease activity to 188% and 173%, respectively, that of the control. β-lactose stimulated the various digestive enzymes to various extents; cellobiose had practically no effect. Glucose and fructose induced the various digestive enzymes to about the same level but to a much higher extent than galactose.

Alpha-glactosidase activity of lactobacilli.

Abstract: alpha-Galactosidase (EC 3.2.1.22) activity was observed in cell-free extracts of Lactobacillus fermenti, L. brevis, L. buchneri, L. cellobiosis, and L. salivarius subsp. salivarius. The cultural conditions under which the enzyme activity was detected suggest that the enzyme is constitutive and present in the soluble fraction in the cell. The enzyme preparations readily hydrolyzed melibiose and other oligosaccharides containing alpha(1 --> 6) linked galactose. Although the cell-free extracts of L. fermenti and L. brevis are negative for beta-fructofuranosidase (EC 3.2.1.26), they hydrolyzed melibiose, stachyose, and raffinose in decreasing order of activity. The beta-fructofuranosidase-positive L. buchneri, L. cellobiosis, and L. salivarius preparations hydrolyzed melibiose, raffinose, and stachyose in decreasing rates of activity. The alpha-galactosidases from different lactobacilli showed optimum activity in pH range 5.2 to 5.9. L. fermenti and L. salivarius preparations exhibited maximum activity between 40 to 44 C and 48 to 51 C, respectively, whereas a 38 to 42 C range was observed for other lactobacilli. Cell-free extract of L. cellobiosis was studied for transgalactosylase activity. When incubated with melibiose, a new compound was detected and tentatively identified as manninotriose.

A new l-glutamic acid-producing species of corynebacterium

Abstract: A Gram-positive non-sporulating rod of L-glutamic acid-producing bacteria, A S 1.299,was isolated from waste liquor of food mamu-facture in Peking. Under the optimum condi-tions, this strain accumulates aerobically a largeammount of L-glutamic acid in a medium con-taining glucose and urea or ammonium salts. Thisglutamic acid-producing bacteria A S 1.299 isidentified as a species of the genus Corynebac-terium, but differs from all known L-glutamicacid-producing bacteria of that genus. The strainexamined, therefore, is considered to a newspecies of genus Corynebacterium, and wasnamed as Corynebacterium pekinense, n. sp. A S1.299. Its taxonomic description is as follows: 1. Cell morphology: Vegetative cells usually short rods withround ends, sometimes club-shaped and slightlycurved rods, 0.7--0.9×1.0--2.5 microns. Occurringin pairs, showing "V" shaped, and also as single,unbranched, elogated cells, with metachromaticgranules, and septa are frequently observed, whenstained with cell wall stain. Gram-positive. Non-motile. Non-sporulating. Not acid fast. 2. Cultural characteristics: On nutrient agar slant the organism givesmoderate growth, filiform, smooth, slightly glis-tening and pale white to slightly yellow. Colonieson nutient agar plate are circular, smooth,slightly glistening, flat to raised, slightly yellowand no pigment penetrated to the medium.Unshaken nutrient broth becomes turbid withringed growth on surface and flocculents sedi-ments. No growth on potato plug is observed.This strain grows abundantly on nutrient agarplate containing 2.6 per cent of urea and 7.5per cent of sodium chloride, respectively. 3. Physiological characteristics: The strain A S 1.299 is facultative anaero-bie. Optimum temperature for growth is 26°-37℃, faint growth at 41℃. The pH for growthrange, from 5 to 10, the optimum pH for growthis about 6--7.5. Nitrite is produced from nitrate.Gelatin is not liquefied. Litmus milk does notchange or slightly alkaline. Casein is not dis-similated. Indole is not produced. N-Paraffinis not utilized as the sole source of carbon. Starchand fat are not hydrolysed. Cellulose is notdecomposed. Hydrogen sulfide is produced.Voges-Proskauer reaction is negative. Methylred test is positive. When Koser's mediumcontaining biotin, citrate is utilized. Positivereaction for catalase and urease are observed.Methylene blue, 2,6-Dibromophenol-inodophenolsodium and diazine green are reduced. Acid butno gas is formed from glucose, fructose, man-nose, maltose, sucrose, trehalose, and inositol;slight acid from dextrin, xylose and galactose.Neither acid nor gas is formed from arabinose,lactose, cellobiose, erythritol, raffinose, sorbose,rhammose, melibiose, melezitose, inulin, glycogen,starch, mannitol, sorbitol, dulcitol, adonitol, gly-cerol, asculin, salicin and 2-methyl-glycoside.Biotin is required as an essential growth factor,and at the same time, thiamine and certainamino acids are found as growth promotingsubstances.