Search PubMed⌕ Search

Biomedical subjects

A K Chatterjee

Publications and source records attributed to A K Chatterjee.

At least 127 records · Page 7Linked to original sources
PubMed1976

Influence of temperature on growth of lipopolysaccharide-deficient (rough) mutants of Salmonella typhimurium and Salmonella minnesota.

Smooth strains of Salmonella typhimurium and S. minnesota, and chemotypes Ra, Rb, and Rc, which are deficient in lipopolysaccharide components of the somatic side chains and outer core region, grow normally on nutrient agar and nutrient broth up to 45 degrees C. However, most mutants with defects in the heptose region of the LPS (chemotypes Rd2 and Re) do not grow on this medium at 42 degrees C or above; a few grow at 42 degrees C but not at 45 degrees C. In liquid medium (nutrient broth, or phosphate minimal medium), growth, measured as turbidity or as colony-forming units, stops 60 to 90 min after shift from 30 to 42 degrees C; DNA and protein synthesis cease at the same time. Growth does not reoccur at 42 degrees C; protein synthesis and growth reinitiate upon shift to 30 or 37 degrees C. Growth cessation does not alter cell morphology in the phase-contrast microscope. Growth of heptose-deficient strains at 42 degrees C in nutrient broth is restored by MgCl2 (0.5 mM), NaCl (50 mM), or sucrose (100 mM). Sensitivity to smooth-specific and rough-specific phages, and analysis of LPS composition, indicate that heptose-deficient mutants grown at temperatures from 30 to 45 degrees C, and in the presence or absence of high salt, do not contain heptose or O-specific sugars in their LPS.

Bacterial Proteins↗
PubMed1976

Leakage of periplasmic enzymes from lipopolysaccharide-defective mutants of Salmonella typhimurium.

Mutants of Salmonella typhimurium with defects in the heptose region of the lipopolysaccharide (LPS) molecule (heptose-deficient, chemotype Re) leak periplasmic enzymes (acid phosphatase (EC 3.1.3.2), cyclic phosphodiesterase, ribonuclease I (EC 3.1.4.22), and phosphoglucose isomerase (EC 5.3.1.9) (PGI is at least partially periplasmic in E. coli and S. typhimurium; see below)) and do not leak an internal enzyme (glucose-6-phosphate dehydrogenase) into the growth medium. The extent of this leakage is markedly increased at higher temperature (42 degrees C). Leakage of periplasmic enzymes from the strains lacking units distal to heptose I in the LPS molecule (chemotype Rd2) occurs only at 42 degrees C, and not at 30 or 37 degrees C. The extent of leakage of these enzymes from smooth strain and mutants of other LPS chemotypes (Rc, Rd1) is not significant, and is not influenced by growth temperatures. The kinetics of leakage of periplasmic enzymes after shift to 42 degrees C in nutrient broth reveal an accelerated release into the medium from heptose-deficient strains of cyclic phosphodiesterase and ribonuclease I after 30 min at 42 degrees C, and phosphoglucose isomerase after 60 min at 42 degrees C; at 30 degrees C the rate of release of cyclic phosphodiesterase and ribonuclease I is relatively slower. After 60 min at 42 degrees C in nutrient broth, growth of these strains has either slowed down or stopped. In L-broth, which permits the growth of the heptose-deficient strain (SA1377) at 42 degrees C, leakage of cyclic phosphodiesterase and phosphoglucose isomerase occurs, whereas there is no detectable leakage of these enzymes from the isogenic smooth strain (SA1355). Thus, leakage of the periplasmic enzymes from the heptose-deficient strain occurs with or without growth. Mg2+ (0.75 mM), sodium chloride (50 mM), and sucrose (100 mM) in nutrient broth at 42 degrees C prevent the leakage of these enzymes. The shedding of LPS from the heptose-deficient as well as the smooth strains is enhanced by high temperature (42 degrees C), whereas considerable leakage of protein occurs only in the heptose-deficient strain at 42 degrees C and not in the smooth strain. The smooth and heptose-deficient strains are equally sensitive to osmotic shock although a significant proportion of acid phosphatase and cyclic phosphodiesterase activities from the heptose-deficient cells grown at 42 degrees C comes off in the Tris-NaCl wash step suggesting a rather loose attachment of these enzymes onto the cell surface.

Acid Phosphatase↗
PubMed1976

Effects of L-lysine administration on certain aspects of ascorbic acid metabolism.

The effects of administration of L-lysine on total ascorbic acid level of various tissues and plasma of rats were studied. The biosynthesis of L-ascorbic acid by the liver tissue was also followed. L-lysine was administered at a dose of 88.3 mg day-1 (20% of LD50) for each 100 g body weight for 14 days. L-lysine administration at the present dose elevated the total ascorbic acid level of liver, kidney, testes, spleen and brain tissues. The plasma total ascorbic acid level was also elevated. The synthesis of L-ascorbic acid from both D-glucuronolactone and L-gulonolactone by the liver was, however, reduced after L-lysine administration. It has been suggested that L-lysine administration at the present dose altered the plasma amino acid pattern which in turn impaired the in vivo synthesis of tissue proteins and, consequently, the synthesis of apoproteins of ascorbic acid-synthesizing enzymes, the D-glucuronoreductase and L-gulonooxidase, were reduced. The elevation in the total ascorbic acid level of extra-hepatic tissues and plasma after L-lysine administration was ascribed to the reduced catabolism and diminished urinary excretion of ascorbic acid.

Animals↗
PubMed1975

Desmoplastic fibroma of maxilla.

Desmoplastic fibroma of the long bones is very rare and has been mentioned in the literature, but there is no mention in the literature of desmoplastic fibroma occurring in relation to maxilla. The first case of desmoplastic fibroma of the maxilla is reported. Conservative surgery is recommended for desmoplastic fibroma of the maxilla to avoid facial deformity.

Adult↗
PubMed1975

Comparison of the cell envelope structure of a lipopolysaccharide-defective (heptose-deficient) strain and a smooth strain of Salmonella typhimurium.

The cell envelope structure of Salmonella typhimurium LT2, which has a heptose-deficient lipopolysaccharide (LPS), is significantly different from that of an isogenic strain with a normal LPS. The rough strain, when examined by freeze-etching, lacks most surface structures that are routinely present in the smooth strain (surface particles and flagella) and has few transmemberane studs in the cytoplasmic membrane (those present are generally found in aggregates), and the outer membrane cleavage is substantially stronger than that of the smooth strain. These envelope differences were independent of both growth temperature and culture age. Examination of ultrathin sections indicated that the rough strain has an outer membrane which forms a much more defined double-track artifact than the smooth strain. The addition of MgCl2 to the growth medium of the rough strain decreased the extent of outer membrane cleavage, and flagella became evident in freeze-etched preparations. The presence of supplemental MgCl2 in the growth medium, which resulted in these morphological changes in the rough strain, also produced growth at a previously restrictive temperature and a decrease in the leakage of periplasmic enzymes. The smooth strain was unaltered morphologically or physiologically by MgCl2 under identical conditions. It is suggested that the outer membrane of the rough strain is more planar.

Cell Wall↗
PubMed1973

Transmission of lac by the sex factor E in Erwinia strains from human clinical sources.

Lactose-utilizing (Lac(+)) strains of Erwinia spp. from human clinical material transfer lac by conjugation to plant strains of Erwinia herbicola and Erwinia amylovora, to other Erwinia strains from human clinical sources, and also to Escherichia coli, Paracolobactrum arizonae, Salmonella typhimurium, and Shigella dysenteriae. The frequency of this transfer varies with the donor and recipient strains employed. The lac genes appear stable in these exconjugants, and they are not cured by acridine orange. The Lac(+) exconjugants transfer lac to an Escherichia coli F(-) Lac(-) strain; the frequency of this transfer is high with E. herbicola and S. typhimurium exconjugants and relatively low with other exconjugants. The most studied Erwinia donor strain from human clinical material (EH133) and its Lac(+) exconjugants are insensitive to the F-specific phage, M13. P1-mediated transduction of lac, by using a Lac(+) exconjugant of E. coli as the donor and an E. coli F(-) Lac(-) strain as the recipient, revealed that all 50 Lac(+) transduced clones tested also inherited donor ability, suggesting a close linkage between the Erwinia sex factor (designated as E) and the lac genes. The E. coli culture harboring E-lac (E and the lac genes linked to it) does not restrict phages T1, T7, and lambdavir. E-lac is compatible with F'his, R100 drd-56 (F-like), and R64 drd-11 (I-like); cells harboring F'his or one of the R factors do not show super-infection immunity to the incoming E-lac, and E-lac plus one of the other plasmids can coexist stably in the same cell. The fertility of cells harboring F'his or R100 drd-56-as determined by the frequency of conjugal transfer of his or of the resistance determinant (Tet(r) in case of R100 drd-56) and also by sensitivity to F-specific phage (M13)-is not altered by the presence of E-lac, and this suggests that the sex factor E might belong to the fi(-) class.

Bacteriological Techniques↗
PubMed1973

Gene transmission among strains of Erwinia amylovora.

Stable donor strains of Erwinia amylovora were obtained from strain EA178R(1) (harboring an Escherichia coli F'lac) by selection for clones resistant to curing by acridine orange. These donor strains (EA178R(1)-99 and EA178R(1)-111) transfer chromosomal markers (arg, cys, gua, ilv, met, pro, ser, trp); the frequency of the appearance of recombinants prototrophic for Cys, Gua, Met, Ser, and Trp is highest (> 10(-5)), followed by recombinants prototrophic for Arg, Ilv, and Pro (10(-7) to 10(-5)). The results of interrupted matings, as well as the frequency of transmission of various markers, suggest that cys is transferred as an early marker by both donor strains. The Hfr state of these donor strains is rather likely on the basis of the following observations. The donor strains exhibit a relatively efficient and possibly oriented chromosome transfer; the Lac(+) character is not cured by acridine orange in these donor strains; and these donor strains do not transfer F.

Acridines↗