Ultrastructure and Host Specificity of Bacteriophages of Streptococcus cremoris, Streptococcus lactis subsp. diacetylactis, and Leuconostoc cremoris from Finnish Fermented Milk "Viili"

"Viili," a fermented milk product, has a firm but viscous consistency. It is produced with traditional mesophilic mixed-strain starters, which have various stabilities in dairy practice. Thirteen morphologically different types of phages were found in 90 viili samples studied by electron microscopy. Ten of the phage types had isometric heads with long, noncontractile tails, two had elongated heads with long, noncontractile tails, and one had a unique, very long elongated head with a short tail. Further morphological differences were found in the tail size and in the presence or absence of a collar, a baseplate, and a tail fiber. To find hosts for the industrially significant phages, we examined the sensitivities of 500 bacterial isolates from starters of the viili. Seven of the phages attacked Streptococcus cremoris strains, three attacked S. lactis subsp. diacetylactis strains, and four attacked Leuconostoc cremoris strains. Some phages differed only in their host specificity. Hosts were not found for 4 of the 13 morphological types of phages.     

DQ α and β RFLP reveals the composition of the DQ molecule recognized by T-cell clones

Pst I RFLP, revealed with DQ and DQ probes, was compared with Taq I RFLP using a panel of DR-homozygous cell lines and HLA-typed family members. Taq I patterns, characteristic for each DR-associated DQ and allelic forms, were recognized in the homozygous state and then proven to segregate in the heterozygous members of informative families. The presence of both specific and chains was found to be necessary to form the type of DQ molecule specifically recognized by two alloreactive T-cell clones. Particular and associations also seem to be responsible for some Dw splits of the DRw6-positive cells. Taq I RFLP analysis may be more complex than the Pst I analysis, but is certainly more informative and complete, considering the type of information we were seeking by performing these types of experiments.Abbreviations used in this paper BSA bovine serum albumin - GLO glyoxalase - kb kilobase(s) - LCL lymphoblastoid cell line - MHC major histocompatibility complex - PBL peripheral blood lymphocyte - PLT primed lymphocyte test - RFLP restriction fragment length polymorphism - SDS sodium dodecyl sulfate - SSC standard sodium citrate - SSCP sodium, sodium citrate, sodium phosphate - TBE Tris-borate, boric acid, ethylenediaminetetraacetate (EDTA) - TCGF T-cell growth factor     

Vasoactive intestinal peptide (VIP) binding to solubilized material from rat liver plasma membranes

A non-ionic detergent such as Lubrol-PX extracts in soluble form the VIP-binding structures of rat liver plasma membranes. Detergent-solubitized proteins bind specifically [¹²⁵I]VIP and the complex tracer-protein is identified by the use of Sepharose 6B columns. The interaction is only possible in the absence of detergent (below 0.001%) and is inhibited by native peptide. A molecular weight of about 80,000 was estimated for VIP-binding proteins by reference to a series of globular markers of proteins. Binding to VIP soluble proteins is specific and dependent on time as studied by the Hummel and Dreyer (Biochim. Biophys. Acta 63:530–532, 1962) assay.     

Antigenic probes locate the myosin subfragment 1 interaction site on the N-terminal part of actin

The interaction of two different anti-actin antibody populations with the myosin subfragment 1-F-actin rigor complex has been studied. In contrast with the 1–7 sequence, the 18–28 sequence appears to be strongly implicated in the contact area of the myosin head on the actin polypeptide chain.     

Species variations amongst proteinases in liver lysosomes

Cathepsin B, H, L and D activities in liver lysosomes were compared between species. Although cathepsin B and D were detected in bovine, pig, chicken and rat liver, striking species differences were evident for cathepsin H and L. Cathepsin L activity was particularly high in chicken lysosomal extracts, but could not be detected in bovine and pig extracts. Whereas there was no significant cathepsin H activity in bovine extracts, rat liver lysosomal extracts contained large amounts of cathepsin H activity.     

Development of gluconeogenesis from different substrates in newborn rabbit hepatocytes

The rates of glucose production from various substrates entering gluconeogenesis at different steps were investigated in hepatocytes isolated from term-fetus and newborn rabbits fasted during the first 2 days of life. The data were compared to the rate of glucose production measured in hepatocytes from young rabbits (50-60 days) starved for 48 h. The net production of glucose from substrates (lactate, pyruvate, propionate, alanine) entering gluconeogenesis below phosphoenolpyruvate was very low at birth and increased during the first day of life, in relation with an increased cytosolic phosphoenolpyruvate carboxykinase activity. The net production of glucose from precursors entering gluconeogenesis at the level of triose phosphates (dihydroxyacetone, fructose) was low at birth but a maximal capacity for gluconeogenesis was reached within 6 h after birth. This enhanced gluconeogenic capacity was associated with a fall in hepatic fructose 2,6-bisphosphate concentration and a reduced glycolytic flux. In contrast, a high glucose production from galactose was already present at birth and did not rise at 24 or 48 h after delivery. These results suggest that the development of gluconeogenic capacity in hepatocytes isolated from newborn rabbit is dependent upon two factors, a decrease in the F2,6-P2 concentration which reduces the glycolytic flux and an increase in the activity of cytosolic phosphoenolpyruvate carboxykinase.     

Antral gastrin- and somatostatin-producing cells and intraluminal peptide secretion in normal subjects and duodenal ulcer patients with and without vagotomy

The behaviour of gastrin (G) cells and somatostatin (D) cells in endoscopic antral biopsies and that of intraluminal gastrin (ILG) and somatostatin (ILS) release in the gastric juice were investigated in three groups of patients: control subjects, duodenal ulcer (DU) patients and DU patients treated by a superselective vagotomy (SSV). G and D cell densities were correlated in the three groups of subjects. The G/D cell ratio was significantly increased in SSV patients (P less than 0.001) as compared to control and DU patients. No correlation was found between gastrin or somatostatin cell densities and basal intraluminal levels of the two peptides. ILG output was significantly higher in DU patients than in control or SSV patients (P less than 0.001). ILS output was also higher in DU patients than in controls (P less than 0.001) and in SSV patients (P less than 0.05). It was also significantly augmented in SSV (P less than 0.001) as compared to control patients. ILG and ILS concentrations were only correlated in controls. Within each of the three groups of subjects, ILG and ILS release varied in function of the gastric juice pH. Our results emphasize the necessity to consider the intragastric pH as well as the physiological or pathological state to study intraluminal peptides in man.     

The amino-acid sequence of rat Cu-Zn superoxide dismutase

The primary structure of Cu-Zn superoxide dismutase isolated from rat liver was determined. The enzyme was reduced, carboxymethylated and fragmented by treatment with cyanogen bromide, trypsin or Staphylococcus aureus proteinase V8. The resulting peptides were separated by gel filtration or high performance liquid chromatography and sequenced by automated Edman degradation. The total sequence of 153 amino-acid residues per subunit was reconstructed from overlapping peptides. Rat Cu-Zn superoxide dismutase proved to be closely related to the corresponding sequences of other mammals in having more than 80% identical amino-acid residues in homologous position and an acetylated N-terminus. Comparison of the rat Cu-Zn superoxide dismutase structure with those of other species suggests a similar phylogenetic distance between rat, man, pig, cattle and horse and a rapid molecular divergence during vertebrate development compared to earlier evolutionary periods.     

Distribution of cytoskeletal proteins sharing a conserved phosphorylated epitope

A group of antigens related by their reactivity with monoclonal antibodies MPM-1 and MPM-2 appear as cells enter mitosis. These antibodies bind to a phosphorylated epitope on certain proteins, and therefore the antigens are presumed to be a group of phosphoproteins. A subset of these proteins has been shown previously to be components of mitotic microtubule organizing centers in PtK1 cells. We present here evidence that the mitosis-specific appearance of these phosphoproteins is a phenomenon common to all eukaryotic cells. The MPM reactive phosphoproteins were localized to mitotic spindle poles regardless of whether the spindle formed in the cytoplasm after nuclear envelope breakdown (open mitosis) or within the nucleus (closed mitosis). This reactivity was not dependent upon the presence of centrioles at the spindle poles. Proteins that contained the phosphorylated epitope were not, however, restricted to mitotic cells. Cells of neuronal derivation and flagellated cells showed specific localization of MPM antibody to the microtubule network and basal bodies respectively. On immunoblots, the MPM antibody reacted with brain MAP-1 among a number of other phosphoproteins. The identification of microtubule-associated protein (MAP)-1 correlates with the localization of the antibody to microtubules of neuroblastoma cells. These results suggest, that different phosphoprotein molecules detected by the MPM antibody may be specific for different mitotic microtubule organizing centers, basal bodies, and other specialized cytoskeletal structures; and the presence of a related phosphorylated domain on these proteins may be important for their proper function and/or interaction with microtubules.     

Preparation and P content of non-pregnant and pregnant human uterine myosin

Myosin content and phosphorus (P) concentration of myosin preparations were measured in non-pregnant and pregnant human myometrial tissue specimens. It was found that the amount of myosin gained from 1 g of minced myometrial tissue is 0.5 mg in the early follicular phase of the menstrual cycle, 0.6-0.7 mg in the late luteal phase, and 6-7 mg during pregnancy. Considering the different functional stages of the myosin sources and the performance characteristics of the methods, the estimated myosin content of non-pregnant myometrium is 1.0-1.5 mg, while 10-15 mg in pregnant myometrial tissue. A considerable amount of P is bound to the preparations. It is the smallest in the post-menstrual period and increases towards the end of the cycle. The largest amount of P is gained from fresh pregnant uterine samples. Analysis of the alkaline hydrolysate showed that the phosphate group was bound to amino acids, in the largest amount to arginine, less to histidine and the smallest amount to lysine and serine. As a function of the duration of storage, especially the P-Arg concentration was decreasing. The prolonged hydrolysis time decreases again the concentration of P-Arg with a consecutive increase of No. 1 and 2 P-containing peaks in the chromatographic profile of alkaline hydrolysate.