The problem of the acts duration measurement in relation to the “focal-animal” technique of behavioral recording

The focal-animal technique assumes the continuous recording of the behavior of an individual during a certain time interval. The length of this interval (sampling unit) can be problematic when estimating the duration of behavioral acts. Two acts from the behavioral repertoire of the ant Leptothorax fuenteiwere focused on in this work at different ranges of temporal scales. Analyzing these acts we show the possibility of existence of a sampling artifact, in such a way that the estimates of the durations of the acts would be forced to depend upon the length of the sampling unit that is being used.     

Comparative effects of a recombinant and a mutein type of granulocyte colony stimulating factor on the growth of Meth-A fibrosarcoma with 5-fluorouracil chemotherapy

The present study was designed to evaluate the effects of a recombinant human G-CSF (rhG-CSF) and a mutein G-CSF(KW-2228) on leucopenia and tumor growth in mice treated with 5-fluorouracil (5-FU). In normal mice, the number of leucocytes (white blood cell, WBC) reached the peak 12 hours after a single injection of either type of G-CSF and decreased to the normal level after 24 hours. Daily administration induced a continuous increase in the WBC count, however, administrations at intervals did not. Meth-A fibrosarcoma was subcutaneously inoculated into the backs of syngeneic BALB/c mice. The mice were treated with 5-FU alone or with G-CSFs. Chemotherapy with 5-FU alone resulted in leucopenia and an insignificant inhibition of tumor growth. The conjunctive administration of G-CSFs with 5-FU resulted in a significantly augmented inhibition of tumor growth, and leukopenia was not seen. This augmenting effect was more prominent with KW-2228.These results suggest that in 5-FU chemotherapy G-CSFs may be beneficial in restoring the number of leucocytes from leucopenic state and in augmenting the tumor inhibitory effect. Furthermore, KW-2228 may be more beneficial than the natural type rhG-CSF.     

Structural genes of glutamate 1-semialdehyde aminotransferase for porphyrin synthesis in a cyanobacterium and Escherichia coli

Summary In bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (Rhodobacter) or Rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-CoA into 5-aminolevulinate as is the case in mammalian cells and yeast. In cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutamate into 5-aminolevulinate. The last step is the conversion of glutamate 1-semialdehyde into 5-aminolevulinate. Using a cDNA clone encoding glutamate 1-semialdehyde aminotransferase from barley, genes for this enzyme were cloned from Synechococcus PCC6301 and Escherichia coli and sequenced. The popC gene of E. coli, previously considered to encode 5-aminolevulinate synthase, appears to be a structural gene for glutamate 1-semialdehyde aminotransferase. Domains with identical amino acid sequences comprise 48% of the primary structure of the barley, cyanobacterial and putative E. coli glutamate 1-semialdehyde aminotransferases. The cyanobacterial and barley enzymes share 72% identical residues. The peptide containing a likely pyridoxamine phosphate binding lysine is conserved in all three protein sequences.     

Expression and stability of amplified genes encoding 5-enolpyruvylshikimate-3-phosphate synthase in glyphosate-tolerant tobacco cells

Two distinct cDNAs for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) were obtained from a glyphosate-tolerant tobacco cell line. The cDNAs were 89% identical and the predicted sequences of the mature proteins were greater than 83% identical with EPSPS proteins from other plants. Tobacco EPSPS proteins were more similar to those from tomato and petunia than Arabidopsis. One cDNA clone, EPSPS-1, represented a gene that was amplified in glyphosate-tolerant cells, while the gene for EPSPS-2 was unaltered in these cells. Consequently, EPSPS-1 mRNA was more abundant in tolerant than unselected cells, whereas EPSPS-2 mRNA was at relatively constant levels in these cell lines. Exposure of unselected cells and tobacco leaves to glyphosate produced a transient increase in EPSPS mRNA. However, glyphosate-tolerant cells containing amplified copies of EPSPS genes did not show a similar response following exposure to glyphosate. A significant proportion of the EPSPS gene amplification was maintained when tolerant cells were grown in the absence of glyphosate for eight months. Plants regenerated from these cells also contained amplified EPSPS genes.     

Lithium treatment of affective disorders: effects of lithium on the inositol phospholipid and cyclic AMP signalling pathways

The effects of lithium (Li⁺) on the adenylyl cyclase and inositol phospholipid receptor signalling pathways were compared directly in noradrenergic and carbachol stimulated rat brain cortical tissue slices. Li⁺ was a comparatively weak inhibitor of noradrenaline-stimulated cyclic AMP accumulation with an IC₅₀ of approx. 20 mM. By contrast, half-maximal effects of Li⁺ on inositol monophosphate (InsP) accumulation in [³H]inositol labelled tissue slices occurred at about 1 mM. A similar IC₅₀ for Li⁺ of about 1 mM was also obtained for noradrenaline-stimulated accumulation of CMP-phosphatidate (CMPPA), a sensitive indicator of intracellular inositol depletion, in tissue slices that had been prelabelled with [³H]cytidine. The effect of myo-inositol (inositol) depletion on the prolonged activity of phosphoinositidase C (PIC) was examined in carbachol-stimulated corticol slices using a novel mass assay fro InsP. Exposure to a maximal dose of carbachol for 30 min in the presence of 5 mM Li⁺ caused a 10-fold increase in the level of radioactivity associated with the InsP fraction, but only a 2-fold increase in InsP mass. During prolonged incubations in the presence of both carbachol and Li⁺ the accumulation of InsP mass was enhanced if 30 mM inositol was included in the medium. The results are comptable with the inositol depletion hypothesis of Li⁺ action but do not support the concept that adenylyl cyclase or guanine nucleotide dependent proteins represent therapeutically relevant targets of this drug.     

Production of cellulolytic enzymes from theXylaria andHypoxylon species of xylariaceae

Eighteen strains of xylariaceous fungi have been screened for higher activities of cellulolytic enzymes,Trichoderma reesei QM 9414 was also examined for comparison. Strains ofXylaria anisopleura andX. regalis had higher endocellulase (CMCase) and exocellulase (Avicelase) activities after 2 weeks' incubation.Hypoxylon stygium produced the highest activity of -glucosidase 3 days after inoculation. The optimum pH for these cellulolytic enzymes was approx. 5.0 and the optimum temperatures ranged from 37 to 50°C. A mixed culture process usingT. reesei QM 9414 andH. stygium was developed to obtain enhanced synthesis of cellulase. -Glucosidase activities in the mixed culture increased within 48h whenH. stygium was introduced after 24h.     

Assessment of membrane potential changes using the carbocyanine dye,diS-C3-(5): synchronous excitation spectroscopy studies

The fluorescence of the voltage sensitive dye, diS-C₃-(5), has been analyzed by means of synchronous excitation spectroscopy. Using this rather rare fluorescence technique we have been able to distinguish between the slightly shifted spectra of diS-C₃-(5) fluorescence from cells and from the supernatant. It has been found that diS-C₃-(5) fluorescence in the supernatant can be selectively monitored at _exc = 630 nm and _em= 650 nm, while the cell associated fluorescence can be observed at _exc= 690 nm and _em = 710 nm. A modified theory for the diSC₃-(5) fluorescence response to the membrane potential is presented, according to which a linear relationship exists between the logarithmic increment of the dye fluorescence intensity in the supernatant, In I/I°, and the underlying change in the plasma membrane potential, _p=_p-°_p. The theory has been tested on human myeloid leukemia cells (line ML-1) in which membrane potential changes were induced by valinomycin clamping in various K⁺ gradients. It has been demonstrated that the membrane potential change, _p,can be measured on an absolute scale. Offprint requests to: J. Plasek     

Degranulation of eosinophilic granule cells induced by capsaicin and substance P in the intestine of the rainbow trout (Oncorhynchus mykiss Walbaum)

Summary Adult rainbow trout (Oncorhynchus mykiss) were injected intraperitoneally with capsaicin, substance P, serotonin, or a control of saline vehicle or bovine serum albumin (0.5 g/g body weight). Fish were sacrificed 30 min and 1,2 and 4 h post-injection, the gut was dissected out, and a small section of the upper intestine was processed for electron microscopy. A significant proportion of eosinophilic granule cells (EGCs) of the intestine were in close association with non-myelinated neuronal bundles in all fish (4 fish per treatment and time period), but there was no significant difference between treatment or time, suggesting that the association was unaffected by these factors. Close examination of EGC ultrastructure showed that fish treated with capsaicin and substance P exhibited limited degranulation of the EGCs in the stratum compactum and extensive crinophagic-like degranulation in the lamina propria. Cells of the lamina propria contained characteristic multivesicular-like bodies. The degranulation was reminiscent of both mast cell degranulation and endocrine cell crinophagy. EGCs of fish treated with serotonin or a control were unaffected, suggesting that the serotoninergic neurons, believed to be involved in gut motility, were not responsible for degranulation. It is apparent that EGCs of the trout intestine may be under nervous control, as has been demonstrated previously for mammalian mast cells.     

Effect of guanidinoethanesulfonic acid on brain monoamines in the mouse

Guanidinoethanesulfonic acid (GES) is known to induce convulsive seizures when administered intracisternally to rabbits and cats. The effects of GES on behavior, electroencephalographic recording and brain monoamine levels were examined in mice. When GES (900 nmol) was intraventricularly injected into mice, focal clonic movements of the face, vibrissae and ears together with twitching of the limbs were observed 0.5–1 min after the injection. Hypersensitivity was observed up to 7 min after the injection, after which the mice behaved normally. GES also induced sporadic spike discharges on electrocorticogram. The levels of 5-hydroxytryptamine (5-HT) of the GES-injected mice were lower than those of the saline-injected mice in the hippocampus, diencephalon, pons-medulla oblongata and cerebellum 5 min after the injection. No changes in the norepinephrine or dopamine levels were found after the GES injection. The level of 5-hydroxyindoleacetic acid increased in the striatum and cerebellum 5 min after the GES injection. These results suggest that GES-induced convulsive activities enhance the serotonergic neuroactivity in order to suppress the convulsions.     

The isolation and characterization of ngm2, a mutation that affects nitrosoguanidine mutagenesis in yeast

Summary We have isolated and characterized a new mutant of Saccharomyces cerevisiae, carrying a single mutant allele that we designate ngm2-1, which is defective with respect to induced mutagenesis. This mutant was isolated by screening mutagenized clones for reduced frequencies of reversion of the his1-7 allele, induced by N-methyl-N-nitro-N-nitrosoguanidine. As judged by the reversion of his1-7 and ilv1-92, ngm2-1 mutant strains are also deficient with respect to mutability induced by methyl methane sulfonate, ethyl methane sulfonate and, at least partially, by UV. UV-induced reversion of the ochre mutation arg4-17 and the frameshift mutation his4-38 was not much affected by ngm2-1, however. Like rev3 and rev7 mutations, ngm2-1 also has little influence on the reversion of the proline missense allele, cyc1-115. Ngm2-1 mutants are only at best very slightly more sensitive to the toxicity of the four mutagens used, and homozygous diploids sporulate normally.