Physiological activity of immobilized cells of Claviceps fusiformis during long-term semicontinuous cultivation

Summary The 550-day semicontinuous cultivation of Claviceps fusiformis immobilized in calcium alginate is documented. The vegetative mycelium from seed or from early-production submerged culture is the best choice for immobilization. No extracellular glucans are produced by immobilized cells. Immobilized spores give low yields of clavine alkaloids. Alginate concentrations in a range of 2%–4% do not influence yield and spectrum of alkaloids. The cytoplasm of the immobilized cells becomes condensed (after 3 days), polysaccharides disappear, and centres of lipid synthesis are formed in the cytoplasm. After 60 days the cells harbour a great number of lipid particles, mitochondria are diminishing and their cristae partly disappear, indicating a decreased respiration capacity. After 350–500 days the volume of most cells is increased many times and the cells are filled with large oval bodies of electrondense material. Chloramphenicol protects immobilized cultures against bacterial contamination.     

Binding of 4-methyl umbelliferyl-α-D-glucoPyranoside to Vicia faba lectin: Fluorescence-quenching studies

On binding toVicia faba lectin, the fluorescence of 4-methylumbelliferyl-α-D-glucoPyranoside was quantitatively quenched showing that the interaction of 4-methylumbelliferyl-α-D-glucoPyranoside took Place in a binding environment. The binding of the fluorescent sugar was saccharide sPecific as evidenced by the reversal of 4-methylumbelliferyl-α-D-glucoPyranoside fluorescence quenching by D-fructose. The association constant,K _a, values for the 4-methylumbelliferyl-α-D-glucoPyranoside was determined by comPetition study emPloying reversal of fluorescence quenching of 4-methylumbelliferyl-α-D-glucoPyranoside by D-fructose. TheK _a value obtained for D-fructose was 1.07 ±0.03 X 10⁴ M^-1 and for 4-methylumbelliferyl-α-D-glucoPyranoside was 1.60 ±0.05 X 10⁴ M^-1 at 15°C. TheK _a values of 2.51 ±0.06 X 10⁴M^-1, l.26 ±0.02 X 10⁴ M^-1 and 0.56 ±0.01 X 10⁴M^-1, resPectively at 10°, 20° and 30°C were obtained from the ChiPman equation. The relative fluorescence quenching, ΔF _a, at infinite concentration of the free saccharide sites ofVicia faba lectin [P′] was 93.5% at 30°C and the binding constant for 4-methylumbelliferyl-α-D-glucoPyranoside lectin interaction as derived by Yank and Hanaguchi equation was 0.63 ±0.01 X 10⁴M^-1.     

Cloning and expression of the gene for a fibronectin-binding protein from Staphylococcus aureus.

The gene encoding the fibronectin-binding protein (FNBP) from Staphylococcus aureus strain 8325-4 was isolated from a gene bank in pBR322. The original clone, containing a 6.5-kb insert, gave a functional product present in the periplasm of Escherichia coli. Analysis of polypeptides isolated after affinity chromatography on fibronectin-Sepharose followed by ion-exchange chromatography revealed two gene products, 87 and 165 kd in mol. wt. The amino acid compositions of these two polypeptides and a native FNBP from S. aureus strain Newman were very similar. Antibodies raised against the native FNBP from strain Newman precipitated the 125I-labelled 165-kd polypeptide, and unlabeled 165- and 87-kd polypeptides as well as native FNBP inhibited the immunoprecipitation reactions. The region of the fnbp-gene encoding the fibronectin-binding activity has been identified and subcloned in an expression vector based on the staphylococcal protein A gene. The resulting product in E. coli is an extracellular fusion protein consisting of two IgG-binding domains of protein A followed by a fibronectin-binding region. The fusion protein binds to fibronectin and completely inhibits the binding of fibronectin to intact cells of S. aureus.     

The dsRNA ofTrichomonas vaginalis is associated with virus-like particles and does not correlate with metornidazole resistance

Twelve metronidazole-resistant and twelve metronidazole-susceptible strains ofTrichomonas vaginalis were tested for the presence of dsRNA. Three resistant and five susceptible strains were found to contain dsRNA which indicated that metronidazole resistance does not correlate with the absence of dsRNA. Electron microscopy showed the homogenates of all dsRNA -positive strains to contain virus-like particles 32 –38 nm in diameter, while no such particles were found in the dsRNA-negative strains. A mutual relationship between the dsRNA and virus-like particles seems to exist. After this paper had been accepted for publication the occurrence of virus-like particles in dsRNA-positive trichomonads was reported by others (Wang A.L., Wang C.C.: The double stranded RNA inTrichomonas vaginalis may originate from virus-like particles.Proc. Nat. Acad. Sci. USA 83, 7956–7961, 1986).     

Partial 1p monosomy in a physically and mentally retarded boy

An 8-year-old boy is reported with marked mental and physical retardation, microcephaly, hypertelorism, mongoloid palpebral fissures, hypoplasia of the maxillary portion of the face, and other discrete anomalies. Deletion of the distal portion of the short arm of the chromosome 1 and the karyotype 46,XY, del(1)(p33----pter) was detected.     

Long-term effects of low-level 239Pu contamination on murine bone-marrow stem cells and their progeny

The effects of long-term internal contamination with 13.3 kBq kg-1 239Pu injected intravenously were studied in 10-week-old ICR (SPF) female mice. Radiosensitivity of spleen colony-forming units (CFU-S) and 125IUdR incorporating into proliferating cells of vertebral bone marrow and spleens were determined in plutonium-treated and control animals one year after nuclide injection. The CFU-S in 239Pu-treated mice were more sensitive to X-rays (D0 = 0.52 +/- 0.01 Gy) than in controls (D0 = 0.84 +/- 0.02 Gy). 125IUdR incorporation into bone marrow and spleen cells was reduced after plutonium contamination. At one year following plutonium injection, the occurrence of chromosome aberrations was evaluated in metaphase figures of femoral bone marrow cells. The frequency of aberrations increased early after plutonium treatment, at later intervals it tended to decrease but not below the control level. While the relative numbers of vertebral marrow CFU-S decreased significantly, but only to 86 per cent of normal, cellularity of vertebral bone marrow, peripheral blood counts and survival of 239Pu-treated mice did not differ from the control data.     

Binding of laminin to oral and endocarditis strains of viridans streptococci.

Attachment of bacteria to the host tissue is regarded as a crucial step in the development of many types of infections. Recent studies by us and others have shown that matrix proteins which serve as adhesion proteins for eucaryotic cells may also be recognized by some bacteria. In the present communication, we report that several strains of viridans streptococci are able to bind to laminin. Most strains isolated from blood and heart valves of patients with endocarditis expressed laminin receptors, whereas only a few of the strains isolated from the oral cavity recognized this protein. This observation indicates that laminin binding might be an important factor in the pathogenesis of viridans endocarditis. Laminin binding to two strains (Streptococcus mitis UAB594 and UAB597) isolated from patients with endocarditis was characterized further. The bacterial cells expressed a limited number of laminin receptors (4 X 10(2) to 1 X 10(3) per cell) which bound the protein in a high-affinity interaction (Kd, 40 to 80 nM). This receptor of S. mitis UAB594 was heat labile and could be solubilized from bacteria by brief digestion with trypsin. Solubilized receptors which competed with cell-bound receptors for 125I-laminin could be adsorbed on laminin-Sepharose but not on Sepharose substituted with fibrinogen or fibronectin. Comparison of laminin receptors from S. mitis with those previously described for Streptococcus pyogenes suggest that different sites in the laminin molecule are recognized by the two bacteria and hence that the corresponding receptor molecules are not identical.