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.     

Putrescine uptake regulation in response to alpha-difluoromethylornithine treatment in Leishmania infantum promastigotes

Summary The putrescine uptake/efflux regulation and their regulatory role on intracellular polyamine pools have been studied in the parasitic protozoa Leishmania infantum. Putrescine uptake was age-dependent with maximal values in logarithmic phase promastigotes and minimal in stationary phase. Moreover, putrescine uptake was activated in response to depletion of intracellular polyamines by alpha-difluoromethylornithine (DFMO) — a well known irreversible enzyme-activated inhibitor of ornithine decarboxylase. Kinetic studies of putrescine uptake induction showed a notable rise in Vmax without Km changes, suggesting a de novo synthesis of putrescine carriers. Putrescine uptake was able to replenish polyamine content and also to recover the proliferative rate in cells treated during 24 hours with DFMO.     

Deconjugation of glucuronides catalysed by UDPglucuronyltransferase

Evidence was found for UDPglucuronyltransferase-catalysed deconjugation of p-nitrophenol-, 4-methylumbelliferone- and phenolphthalein-glucuronides. The evidence is based on the following observations: 1, deconjugation is UDP-dependent and the reactions show Michaels-Menten kinetics with respect to UDP and glucuronide saturability; 2, UDP-glucuronic acid was identified as reaction product; 3, all studies were done in the presence of a beta-glucuronidase inhibitor; 4, induction profiles, using 3-methylcholanthrene and phenobarbital as inducing agents, were identical for conjugation and deconjugation reactions. Optimal deconjugation rates for p-nitrophenol- and 4-methylumbelliferone-glucuronides were at pH 5.1 and for phenolphthalein-glucuronide at pH 6.5. Only conjugation reactions showed latency; the corresponding deconjugation reactions were not latent. UDPglucuronyltransferase is a group of oligomeric isoenzymes with different molecular masses. The molecular masses of the isoenzyme species catalysing the forward and reverse reactions were determined by radiation-inactivation analysis. The molecular masses of the isoenzyme species mediating the catalyses of deconjugation reactions were significantly smaller than those mediating catalyses of conjugation reactions: 66 +/- 4 kDa vs. 109 +/- 7 kDa for p-nitrophenol; 82 +/- 8 kDa vs. 105 +/- 6 kDa for 4-methylumbelliferone; and 74 +/- 8 kDa vs. 159 +/- 14 kDa for phenolphthalein. This suggests that for catalyses of deconjugation reactions only part of a UDPglucuronyltransferase isoenzyme is needed, whereas for forward reactions the complete isoenzymes are required.     

Organic microscopic remains in Miocene lacustrine sediments near Libros (Teruel,Spain)

Siliceous remains from Miocene lacustrine sediments near Libros (Teruel, Spain) are studied. Most of them are sponge spicules and may be assigned to Ephydatia fluviatilis. Some chrysophycean cysts and several diatom genera (Melosira, Cyclotella, Fragilaria, Navicula, Pinnularia, and Cymbella) have also been found.     

Morbidity in Chagas' disease. IV. Longitudinal study of 10 years in Pains and Iguatama, Minas Gerais, Brazil

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.     

cAMP-dependent phosphoprotein changes in the yeast Saccharomyces cerevisiae

Abstract cAMP-dependent phosphoprotein changes were determined using 1-dimensional SDS-gel electrophoresis in a cAMP-requiring yeast mutant ( Saccharomyces cerevisiae AM18). During cAMP starvation, the yeast cells accumulated 3 ³²P-labeled bands with M _r/ 72000, 54000, and 37000. The M _r/ 72000 protein was the most prominent phosphorylated protein. After the readdition of cAMP, these phosphoproteins lost their ³²P-label while phosphoproteins with M _r/ 76000, 65000, 56000 and 30000 were accumulated. Similar phosphoprotein changes were also detected in cdc35 at the nonpermissive temperature, but not in wildtype (A363A) or cdc7 strains of S. cerevisiae .     

Mixing patterns in Amazon lakes

The diel mixing patterns of two small floodplain lakes, Lago Jacaretinga in the Amazon drainage, and Lago Cristalino in the Rio Negro system, were investigated during both the high-water and low-water states of the Amazon River hydrograph. Measurements included temperature, oxygen, ammonia, phosphate, and chlorophyll. In both lakes thermal stratification developed during the day and was eroded at night. During the low-water period when the lakes were shallow, nocturnal circulation extended to the lake bottom, whereas when the lakes were deeper (greater than about 5 m), circulation did not reach the bottom and an anoxic hypolimnion developed. During the low-water period, percent of oxygen concentrations were relatively high but always less than saturation. Low oxygen concentrations were observed during the high-water period. At all times nocturnal mixing supplied a significant amount of oxygen to the lake ecosystems. Nighttime upward mixing of recycled nitrogen and phosphorus also appeared to be important nutrient sources for algal productivity.     

Locus determining the human sperm-specific lactate dehydrogenase,LDHC, is syntenic with LDHC

From the data presented in this report, the human LDHC gene locus is assigned to chromosome 11. Three genes determine lactate dehydrogenase (LDH) in man. LDHA and LDHB are expressed in most somatic tissues, while expression of LDHC is confined to the germinal epithelium of the testes. A human LDHC cDNA clone was used as a probe to analyze genomic DNA from rodent/human somatic cell hybrids. The pattern of bands with LDHC hybridization is easily distinguished from the pattern detected by LDHA hybridization, and the LDHC probe is specific for testis mRNA. The structural gene LDHA has been previously assigned to human chromosome 11, while LDHB maps to chromosome 12. Studies of pigeon LDH have shown tight linkage between LDHB and LDHC leading to the expectation that these genes would be syntenic in man. However, the data presented in this paper show conclusively that LDHC is syntenic with LDHA on human chromosome 11. The terminology for LDH genes LDHA, LDHB, and LDHC is equivalent to Ldhl, Ldh2, and Ldh3, respectively.     

Genetic Analysis of Murine Arylsulfatase C and Steroid Sulfatase

SWR/J mice possess two- to threefold higher 4-methylumbelliferyl sulfate (4MUS), dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate (E1S) sulfatase activities in liver and kidney extracts than do A/J mice. These interstrain activity differences are maintained throughout the 6- to 45-day postnatal period. Characteristics of the hepatic activities of SWR/J mice suggest that all three activities reside in the same enzyme. Biochemical properties of the SWR/J and A/J enzyme were not significantly different. Expression of hepatic enzyme activity is subject to regulation by an autosomal locus possessing two alleles with additive effects. Postnuclear E1S- and DHEAS-sulfatase activities are primarily microsomal. Although postnuclear hepatic 4MUS-sulfatase activity is predominantly microsomal, renal activity is primarily nonmicrosomal. Only that portion of 4MUS-sulfatase occurring in cell membranes appears capable of hydrolyzing E1S and DHEAS. The hepatic- and renal-specific subcellular distributions of 4MUS-sulfatase activity may reflect tissue differences in enzyme processing. Renal 4MUS-sulfatase activity is also controlled by an autosomal gene with two alleles having additive effects. Positive correlation between hepatic and renal 4MUS-sulfatase activities indicates that both activities are most likely influenced by the same gene.     

Regulatory interaction of photosynthetic nitrate utilization and carbon dioxide fixation in the cyanobacterium Anacystis nidulans

The rate of photosynthetic nitrate utilization in Anacystis nidulans is strongly influenced by the availability of carbon dioxide. This dependence can be relieved by inhibiting the metabolism of the ammonium derived from nitrate reduction. Nitrate uptake seems to be modulated through a sensitive regulatory system integrating the photosynthetic metabolism of carbon and nitrogen, with CO₂ fixation products antagonizing the inhibitory effect of ammonium derivatives.