Further study on polyamine compositions in Vibrionaceae

It has previously been reported that norspermidine, one of the unusual polyamines, is present in Vibrio species. To expand this observation, the cellular polyamine compositions of additional species and strains in the family Vibrionaceae (Vibrio, Photobacterium, Listonella, and Shewanella) as well as Aeromonas species and Plesiomonas shigelloides, which have been proposed to be excluded from Vibrionacea, were determined by using gas-liquid chromatography. Some Vibrio species previously reported were reexamined under the same conditions, and their results are included in this report. Norspermidine was detected as a major triamine in 23 of 24 Vibrio species, all of 4 Listonella species, and 3 of 5 Photobacterium species. Vibrio costicola, Photobacterium fischeri, and Photobacterium phosphoreum contained no norspermidine. Listonella species were indistinguishable from Vibrio species in their polyamine profiles. However, Schewanella putrefaciens ATCC 8071, formerly allocated in the genus Alteromonas, contained no norspermidine, and its polyamine profile was similar to those of four Aeromonas species, in which putrescine was exclusively found. Plesiomonas shigelloides was very similar to Escherichia coli in that putrescine and spermidine were predominant polyamines. Our data indicate that the occurrence of norspermidine may be very helpful as a generic marker in identification and classification of Vibrio and Listonella species. A gas-liquid chromatographic method with a nitrogen-selective detector was presented for rapid and sensitive detection of cellular norspermidine.     

Proline status of genetically stable salt-tolerant Brassica juncea L. somaclones and their parent cv. Prakash

Three Brassica juncea L. somaclones (SR-1, -2 and -3) selected in vitro for NaCl-tolerance, non-selected somacone (CP-5) and parent cv. Prakash were characterized for their free proline contents in the absence of stress and as a function of increasing salt stress. In the R₀ generation, SR-3 somaclone had ca. three times higher free proline as compared to parent Prakash and other somaclones. Somaclone, SR-1, turned out to be sterile. The other somaclones were carried forward to the R₂ generation after making selections for yield and yield components in the R₁ generation. SR-3 bred true for its high proline accumulating characteristic. The somaclone SR-3 thus had a stable genetic variation for proline overproduction. Free proline content in 7-day-old whole seedlings and 6-week-old plant leaf tissue, increased with the increase in salt stress in all the lines but at differential rates. The magnitude of increase in free proline was much higher in SR-3 lines as compared to parent Prakash and SR-2 salt-tolerant somaclones. Under salt stress, in leaf tissue, one of the SR-3 derived lines (SR3P6-2) accumulated as much as 269 moles of free proline as compared to ca. 20 moles per g dry weight in parent Prakash and SR-2 line. It was interesting to note that there was a critical point concentration of NaCl beyond which the endogenous level of free proline rose sharply. Somaclonal lines (SR3P6-2, SR2P1-2 and CP5-2) which were found to have higher salt-tolerance indices, also had higher critical points as compared to the other relatively salt sensitive genotypes. The relationship between relative water content and osmotic potential of leaves under saltstress also showed a relatively higher degree of osmotic adjustment in the selected somaclones, the maximum being in SR-3 derived lines.     

Activation of K+ channels by lanthanum contributes to the block of transmitter release in chick and rat sympathetic neurons

Summary We studied the effects of lanthanum (La³⁺) on the release of ³H-norepinephrine(³H-NE), intracellular Ca²⁺ concentration, and voltage clamped Ca²⁺ and K⁺ currents in cultured sympathetic neurons. La³⁺ (0.1 to 10 m) produced concentration-dependent inhibition of depolarization induced Ca²⁺ influx and ³H-NE release. La³⁺ was more potent and more efficacious in blocking ³H-NE release than the Ca²⁺-channel blockers cadmium and verapamil, which never blocked more than 70% of the release. At 3 m, La³⁺ produced a complete block of the electrically stimulated rise in intracellular free Ca²⁺ ([Ca²⁺] _i ) in the cell body and the growth cone. The stimulation-evoked release of ³H-NE was also completely blocked by 3 m La³⁺. However, 3 m La³⁺ produced only a partial block of voltage clamped Ca²⁺ current (I _Ca). Following La³⁺ (10 m) treatment ³H-NE release could be evoked by high K⁺ stimulation of neurons which were refractory to electrical stimulation. La³⁺ (1 m) increased the hyperpolarization activated, 4-aminopyridine (4-AP) sensitive, transient K⁺ current (I _A ) with little effect on the late outward current elicited from depolarized holding potentials. We conclude that the effective block of electrically stimulated ³H-NE release is a result of the unique ability of La³⁺ to activate a stabilizing, outward K⁺ current at the same concentration that it blocks inward Ca²⁺ current.     

Genomic termini of equine herpesvirus 1.

After cell infection with the equine herpesvirus 1 (EHV-1), the termini of the linear double-stranded DNA genome fuse to form circular forms. To investigate the mechanisms in the generation and cleavage of such replicative-form DNAs, the genomic termini, the fusion of termini from replicative-form molecules, and the junction between the short and long genome segments have been analyzed by restriction mapping, blot hybridizations, cloning, and sequencing. The data suggest that the genome ends are not redundant and that the genomic termini are fused in replicative intermediates via 3' single-base extensions at the termini of the unique long segment (UL) and terminal repeat (TR). Adjacent to the EHV-1 termini are AT and gamma sequence elements highly conserved among different herpesviruses. We propose that both of these sequence elements are important for the cleavage of EHV-1 replicative forms.     

Idiotype vaccine for tumor by anti-idiotypic antibody prepared against anti-(bacillus Calmette Guèrin)BCG monoclonal antibody

Summary The anti-idiotypic antibody (Ab2) prepared against the anti-BCG monoclonal antibody (mAb) (Ab1) exhibited potential vaccine activity against Meth A fibrosarcoma that shared a common antigen(s) withMycobacterium bovis strain bacillus Calmette Guèrin (BCG). Mice vaccinated with the anti-idiotypic antibody (Ab2) were protected significantly against growth of the transplanted Meth A tumor (66%), and the presence of anti-(anti-idiotypic antibody) (Ab3) was proved in the Ab2-vaccinated mice by enzyme-linked immunosorbent assay and indirect immunofluorescence analyses using unabsorbed or absorbed sera against the BCG antigen(s) and Meth A tumor cells. This indicated that the anti-idiotypic antibody (Ab2) mimicked the structures of the BCG antigen(s) and behaved as the BCG antigen(s) to induce the Abl-like antibody (Ab3) in vivo. Presumably the Ab2-induced Ab3 plays a significant role in preventing growth of the transplanted tumor in animals. By contrast, the control mice treated with normal mouse serum failed to inhibit the tumor growth. These results suggest the possible development of a tumor vaccine from the anti-idiotypic antibody (Ab2) prepared against the anti-BCG monoclonal antibody, for tumors sharing a common antigen(s) withMycobacterium bovis strain BCG.

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Idiotype vaccine for tumor by anti-idiotypic antibody prepared against anti-(bacillus Calmette Guèrin)BCG monoclonal antibody

     

Characterization of interactions between CCK-33 and CCK receptors in isolated dispersed pancreatic acini.

In isolated dispersed pancreatic acini, we have characterized the interactions between cholecystokinin (CCK) and CCK receptors by simultaneously measuring CCK-33 immunoreactivity and CCK bioactivity. Incubation of acinar cells with CCK-33 at cell density of 0.2-0.3 mg acinar protein per ml resulted in stimulation of amylase release concomitant with significant and time-dependent decrease of the immunoreactive CCK. With L-364,718 (0.1 microM), a specific CCK receptor antagonist, immunoreactive CCK levels in the media were not significantly altered during incubation; however, CCK-stimulated amylase release was almost completely abolished (94% inhibition). Vasoactive intestinal peptide (1 nM) significantly potentiated CCK stimulated amylase release without affecting immunoreactive CCK in the media. Insulin (167 nM) did not affect the CCK stimulated amylase release or immunoreactive CCK in the media. Incubation of acinar cells with CCK-33 at 4 degrees C did not affect the levels of immunoreactive CCK; however, a significant change in levels of immunoreactive CCK were found at 37 degrees C at 90 min. Incubation of cell free medium with CCK-33 in the presence or absence of secreted enzymes revealed no changes in CCK immunoreactivity in the medium at 90 min. Addition of bacitracin in the incubation media did not affect the CCK immunoreactivity or bioactivity. These findings indicate that in isolated rat pancreatic acini, CCK-33 stimulates amylase release through a receptor that is specifically blocked by L-364,718. Specificity of the interactions of CCK-33 with acinar cells in the media appears to be receptor-mediated and time- and temperature-dependent.