fimA-folD genes linkage in Salmonella identifies a putative junctional site of chromosomal rearrangement in the enterobacterial genome

Abstract Analysis of the Salmonella chromosomal region located upstream of the fimA gene (coding for the major type 1 fimbrial subunit) showed a close linkage of this gene to the folD gene (coding for the enzyme 5,10-methylenetetrahydrofolate dehydrogenase/5, 10-methenyltetrahydrofolate cyclohydrolase), indicating that the fim gene cluster of Salmonella , unlike that of Escherichia coli , has no regulatory genes located upstream of fimA and apparently terminates with this gene. The respective locations of the fim and folD genes in the E. coli and Salmonella genetic maps suggests that the fimA-folD intergenic region of Salmonella encompasses a junctional site of a genetic rearrangement that probably originated from the different chromosomal location of the fim genes in these species.     

Hydrolysis and protection from hydrolysis of enkephalins in human plasma

Seven groups of enkephalin-degrading enzymes and three groups of inhibitors active on these enzymes were separated from human plasma. The activity of the enzymes in hydrolyzing enkephalins and of the inhibitors in protecting enkephalins from proteolysis was measured. Results obtained with the endogenous inhibitors were compared to those relative to synthetic inhibitors. Data obtained indicate that all enkephalin-degrading enzymes found in plasma are significantly inhibited by the endogenous substances present in this tissue. The inhibition of the different classes of plasma enzymes by two of the three groups of endogenous substances is quite uniform, while one group of inhibitors appears specific to dipeptidylpeptidases. Results obtained are discussed in terms of the functional role of the inhibitory substances and of the possible pharmacological implication of their presence in human plasma.     

Voltammetric studies on the electrochemical behaviour of membrane-entrapped hemes

Summary The electrochemical behaviour of Fe(III)-protoporphyrin IX entrapped into a cellulose triacetate membrane has been investigated by cyclic voltammetry. The physical entrapment into a solid matrix does not modify the redox properties of the entrapped berries, which also act as efficient promoters in the electrochemistry of cytochromec. Such a system represents a promising example of a simple solid-state promoter, and stimulates further investigations in order to obtain more complex systems that may be of significance for basic and applied bioelectrochemistry.     

Pericentric inversion of chromosome 19 in three families

Summary Pericentric inversion of chromosome 19 has been found in several members of three unrelated families from a restricted geographical region. In one of the families, an additional pericentric inversion of chromosome 9 was observed. Reproductive problems, multiple abortions in two families and a neonatal death in the third, were present. A review of previously described cases is included, and the genetic risk connected with this type of rearrangement is also discussed.     

Antibiotic resistance in strains of Listeria spp. from meat products

The susceptibility or resistance to 26 antimicrobial agents was determined for 64 strains of Listeria monocytogenes and 102 strains of L. innocua isolated from Italian meat products. Some strains of L. monocytogenes were found to be resistant to tetracycline, erythromycin, co-trimoxazole and clindamycin. No plasmids were found in any L. monocytogenes strain. Five strains of L. innocua contained a 7.9 kbp plasmid, but these isolates were not resistant to any antibiotic in common and treatment with curing agents could not eliminate resistance to antibiotics. These results suggest that antibiotic resistance was not likely to be plasmid mediated in our strains.     

Characterization of amine oxidases from pisum, lens, Lathyrus and Cicer

Amine oxidases have been purified to homogeneity from Pisum sativum, Lens esculenta, Lathyrus sativus and Cicer arietinum. The enzymes have a M_r. of 150 000 and are composed of two identical subunits of 72 000. The amine oxidases showed an isoelectrophoretic heterogeneity.     

Effect of drug treatment on liver-slice function following 72-hour hypothermic perfusion

The viability of hypothermically perfused dog liver was evaluated with a tissue-slice technique. After being preserved for 72 hr, slices of liver were incubated at 30 degrees C for as long as 2 hr; then water content, K+/Na+ ratio, and ATP concentration were measured. Dog livers were assigned to the following experimental groups: Group 1 (no preservation; control); Group 2 (livers preserved for 72 hr); Group 3 (donor animals pretreated with 3.5 mg/kg of chlorpromazine (CPZ) and 20 mg/kg of methylprednisolone (MP), and livers preserved for 72 hr); Group 4 (livers pretreated with 2-deoxycoformycin (2-DOC), 50 mg/liter, and preserved for 72 hr); and Group 5 (combination of Group 3 and Group 4 treatments). Livers in Groups 2, 3, and 4 lost K+ during preservation, and the mean K+/Na+ ratio significantly decreased from a control value of 4.2 +/- 0.4 to 1.5-1.9 (P less than 0.05). Group 5 livers did not lose K+; mean K+/Na+ ratio was 3.9 +/- 0.5. Fresh livers (no preservation) rapidly reaccumulated K+ when the tissue slices were incubated for 2 hr at 30 degrees C; mean K+/Na+ ratio was 3.7 +/- 0.5. Tissue slices from Group 2 livers (72 hr preservation), and livers pretreated with CPZ-MP (Group 3) or pretreated with 2-DOC (Group 4) did not significantly reaccumulate K+ at 30 degrees C; mean K+/Na+ ratio was 1.7-2.1. Only slices prepared from liver pretreated with both CPZ-MP and 2-DOC reaccumulated K+; mean K+/Na+ ratio was 4.6 +/- 1.2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phase II study of vaccinia melanoma cell lysates (VMCL) as adjuvant to surgical treatment of stage II melanoma

Summary Patients with stage II melanoma were vaccinated with vaccinia virus-induced melanoma cell lysates (VMCL). The vaccine contained viable vaccinia virus, membranous fragments and no intact nuclei. A number of antigens defined by monoclonal antibodies were detected in the vaccine including the ganglioside GD3 and DR antigens. Administration of the vaccine was associated with depression of natural killer cell activity against melanoma and K562 target cells in the first 3–6 months of treatment. Leucocyte dependent antibody (LDA) activity against melanoma cells was induced or increased in titre in approximately half of the patients studied. Continued vaccination was associated in a number of patients with a decrease in LDA titres. Studies on a small sample of patients revealed that this was associated with the development of serum factors which inhibited LDA activity. LDA activity appeared directed to non-MHC antigens on melanoma cells which were of at least two specificities. One specificity which was shared with antigens on a number of non-melanoma carcinoma cells was removed by absorption on fetal brain and may be similar to oncofetal antigens described by other workers. Reactivity against melanocytes was induced in some patients and may underlie the development of vitiligo in several patients. These results suggest that vaccines prepared from VMCL may be a favourable method for increasing immune responses against melanoma.     

Increase of the glycolytic rate in human resting fibroblasts following serum stimulation. The possible role of the fructose-2,6-bisphosphate

We report that glycolysis in human quiescent fibroblasts stimulated by serum addition is increased, and that the changes of the metabolic route reflect the activity of the phosphofructokinase. A possible role of fructose-2,6-bisphosphate as a positive modulator of the key enzyme is proposed.