Seasonal Variations in the Circadian Activity of Ache in the Brain Stem Reticular Formation of Mice Under Normal and Constant Light Regimens

AChE activity in mouse brain stem reticular formation was studied at 4hr intervals for 48 hr at 4 different times of the year under normal (LD 12/12) and constant light (LL) regimens. Under both illumination regimens, a significant ultradian rhythm of AChE activity was observed. In the investigated seasons of the year, changes in AChE behaviour were limited to mean activity of the enzyme (median) as well as to the amplitude and acrophase of the rhythm.     

Serpin alpha 1proteinase inhibitor probed by intrinsic tryptophan fluorescence spectroscopy.

Various conformational forms of the archetypal serpin human alpha 1proteinase inhibitor (alpha 1PI), including ordered polymers, active and inactive monomers, and heterogeneous aggregates, have been produced by refolding from mild denaturing conditions. These forms presumably originate by different folding pathways during renaturation, under the influence of the A and C sheets of the molecule. Because alpha 1PI contains only two Trp residues, at positions 194 and 238, it is amenable to fluorescence quenching resolved spectra and red-edge excitation measurements of the Trp environment. Thus, it is possible to define the conformation of the various forms based on the observed fluorescent properties of each of the Trp residues measured under a range of conditions. We show that denaturation in GuHCl, or thermal denaturation in Tris, followed by renaturation, leads to the formation of polymers that contain solvent-exposed Trp 238, which we interpret as ordered head-to-tail polymers (A-sheet polymers). However, thermal denaturation in citrate leads to shorter polymers where some of the Trp 238 residues are not solvent accessible, which we interpret as polymers capped by head-to-head interactions via the C sheet. The latter treatment also generates monomers thought to represent a latent form, but in which the environment of Trp 238 is occluded by ionized groups. These data indicate that the folding pathway of alpha 1PI, and presumably other serpins, is sensitive to solvent composition that affects the affinity of the reactive site loop for the A sheet or the C sheet.     

Phenotypic and genotypic stability of multiple lines of transgenic pigs expressing recombinant human protein C

The genotypic and phenotypic stability of four lines of transgenic pigs expressing recombinant human protein C in milk was examined. Two lines were established with a construct consisting of a 2.6 kb mouse WAP promoter and a 9.4 kb human protein C genomic DNA. Two lines were established with another construct consisting of a 4.1 kb mouse WAP promoter and a 9.4 kb human protein C genomic DNA. Genotypic stability was measured by transgene copy number transmission. Outbred offspring having a single transgene integration locus were established from a founder having three independent, multicopy loci. Phenotypic stability over multiple lactations was defined by the combination of recombinant human protein C expression levels and the isoform signature of recombinant human protein C in western blots. Both cDNA and genomic human protein C transgenes gave similar ranges of expression levels of about 100--1800 g ml–1. Within a given outbred lineage having a single loci for the cDNA transgene, the expression levels ranged between 100--400 g ml–1. Western blots of reduced recombinant protein C revealed that single chain content was not dependent on expression level and was consistent within each transgenic line, but varied between transgenic lines. This suggests that native swine genetics may play a role in selection of production herds with optimal post-translational proteolytic processing capability. Although swine are not conventional dairy livestock, it is agreed that the short generation times, multiple offspring per litter, stable paternal transmission of the transgene, and milk production capabilities of swine offer distinct advantages over conventional dairy livestock for the establishment of a herd producing a therapeutic recombinant protein     

Mycological flora isolated from people in Poland

It has been shown that in Poland the most frequently encountered pathogenic fungi are the zoophilic ones:T. mentagrophytes, M. canis andT. verrucosum. The zoophilic fungi have been isolated in 69.6 % of cases, while the anthropophilic fungi in 30.3 % of cases. In Poland, the most frequently isolated fungus among anthropophilic fungi have beenT. rubrum (36.2 %) andT. violaceum (34.3 %), whereasT. schoenleinii has been found in 5.7 % of cases. The geographical distribution of the anthropophilic fungi indicates that they appear most frequently in the counties of Biaystok (58.2 %), Katowice (40.5 %), and Warsaw (36.5 %), while the zoophilic fungi are found prevalently in the counties of ód (93.0 %), Kielce (84.7 %) and in that of Szczecin (83.8 %). It has been ascertained that the diseased animals and sick persons form the main reservoirs of the pathogenetic fungi. For the prophylactic purposes it is indispensable to promote among the population the sanitary instructions and propagate the principles of personal hygiene, which play a very important role in preventing mycosis. Within the framework of antimycosis campaigns it is necessary to widen the collaboration between the dermatologists and veterinary surgeons.Summary The author came to the conclusion that people in Poland suffer mostly of zoo-philic (69.9 %) than of anthropophilic dermatomycoses (30.3 %).Trichophyton rubrum was observed in 36.2 %,T. violaceum in 24.3 % andT. schoenleinii in 5.7. %. The main reservoir of dermatomycoses in Poland are sick animals and people. In the fight against mycoses of people and animals the collaboration of dermatologists and veterinarians is absolutely necessary.

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Résumé L'auteur a démontré qu'en Pologne chez les hommes la fréquence des dermatomycoses zoophiles est plus haute (69.7 %) que celle des dermatomycoses anthropophiles (30.3 %). Trichophyton rubrum noté dans 36.2 %,Trichophyton violaceum dans 24.3 % etTrichophyton schoenleinii dans 5.7 % cas. Les réservoirs principaux des mycoses en Pologne sont les animaux et les hommes malades. Dans la lutte contre les mycoses chez les hommes et chez les animaux, il est indispensable de constituer une collaboration stricte entre les dermatologues et les véterinaires.

     

Inhibition of calf thymus DNA polymerase α and of normal and cancer cell growth by butylanilinouracil and butylphenylguanine

6-(p-n-Butylanilino)uracil and N²-(p-butylphenyl)guanine inhibited the activity of DNA polymerase α from calf thymus but had no effect on other eukaryotic polymerases (DNA polymerases β and γ) or Escherichia coli DNA polymerase I. Inhibition was competitive with deoxyguanosine 5′-triphosphate and did not occur in the reaction of DNA polymerase α with a template that did not contain cytosine residues. The results support a mechanism which involves hydrogen bonding of inhibitors with cytosines in the DNA template and binding with an inhibitor specific site on the enzyme. A screen of inhibitor effects on normal and cancer cell growth in culture showed that cells were not uniformly sensitive to these compounds, a mouse lymphoma line being least sensitive and a human lung cancer line being most sensitive. It is suggested that these inhibitors may be useful to probe possible structural differences among DNA polymerases α.     

Rotifer communities of ponds supplied with post-waste water

The studies concern the changes in communities of rotifers in a model system of 4 through-flow ponds linked in a row and constantly supplied with waste-water after mechanical-biological treatment. Studies were carried out from the spring of 1977 to the spring of 1978 – i.e. during the first year the ponds were used.
Twenty-four species of rotifers, forming three cenotic communities differing in number of species, dominance structure and abundance, were found. Gradually increasing similarity of communities with the distance from the source of post-waste water reflects the increasing stability of physico-chemical and biological conditions in the examined model ecosystem.
Maximum biocenotic stability was observed in the last pond with the highest specific differentiation, and also considerable share of oligo- and β-mesosaprobionts, the highest frequency of species and slight differences in abundance between the dominant and accompanying species.
The role of trophic factor in formation of rotifer communities in the successive links of the presented model pond system is pointed out.     

Conformation of LiDNA in solutions of LiCl

We have derived radii of gyratin, R_g, from the absolute intensity of the scattered light of mondisperse linear Col E₁ LiDNA in solution at various LiCl concentrations up to 5M. The second virial coefficients, A₂, decrease strongly with increasing LiCl concentration, and vanish between 3 and 5M LiCl. It was thus possible to calculate a limiting value at a high salt concentration of 28.5 nm for the persistence length, a₀, of LiDNA, without the necessity of applying excluded-volume corrections. The value obtained is in good agreement with the value previously obtained for NaDNA at high NaCl concentrations, and can be identified with the high salt limit of DNA flexibility, with long-range electrostatic interactions effectively screened. Sedimentation coefficients in the ultracentrifuge and apparent and translational diffusion coefficients (at finite and vanishing scattering vectors, respectively) from dynamic laser-light scattering have also been obtained up to 5M LiCl. From the sedimentation and apparent diffusion, D(90), (at 90° scattering angle only) above 5M, and up to 9M LiCl, it could be shown that the solutions are stable for reasonable periods of time, and the molecular parameters vary smoothly and moderately at high salt. Conformational transitions were not observed and precipitation occurs between 9 and 10M LiCl.     

Behavioral effects of long-term exposure to magnetic fields in rats

Male rats and pregnant and nonpregnant female rats of the Wistar strain were sham-exposed or exposed to static (0.49 T) or to extremely low frequency (50 Hz) magnetic fields (0.018 T) 2 h per day for 20 consecutive days. Measures of irritability, exploratory activity, and locomotion were made in that order before and after the 4th, 10th, and 17th 2-h exposures. A reliable decrease in the irritability of rats after repeated exposure to a static or undulating field was found. No significant effects of treatment conditions on open-field behavior and locomotor activity were observed. Pregnancy had no influence on the behavioral end points. These results indicate that irritability of rats may be used as a simple behavioral indicant of mammalian sensitivity to magnetic fields. © 1993 Wiley-Liss. Inc.     

Effect of aluminum chloride on mitogenesis,mitosis, and cell cycle in human short-term whole blood cultures: Lower concentrations enhance mitosis

Aluminum, the third most common element in the earth's crust (second to oxygen and silicon) and recently suspected by some investigators to be implicated in Alzheimer disease etiology, has been studied in relation to its effect on mitogenesis, mitosis, and cell cycle. We have observed that 2–4 mM concentrations of AlCl₃ have decreased the number of cells that undergo mitogenesis (PHA-induced blast transformation) and mitosis in human short term whole blood cultures. We have also shown that the rate of the cell cycle was slowed down, i.e., cell cycle time was increased in the presence of AlCl₃. Also, we have demonstrated a reversible effect on aluminum-induced reduced mitotic index in long-term EBV-transformed lymphoblastoid cultures. Although safeguards such as limiting aluminum serum concentrations have been recommended to protect individuals undergoing dialysis, it should be realized that concentration accumulations of aluminum may increase over chronic exposures. Accordingly, if the number of cells stimulated by PHA is reduced in the presence of AlCl₃, there may be a reduction of immune competence, since the degree of PHA stimulation has been used as an indicator of immune response. Similar reductions in mitotic index could affect every tissue involved with cell division. Although it may not be the same for higher concentrations, from our results, we have also shown that decreased mitotic rates were reversible in long-term EBV-transformed lymphoblastoid cultures. Increased numbers of mitoses were observed in human short-term whole blood cultures that were exposed to 2 μM concentrations of aluminum chloride. The concentration is close to those found in normal human serum and within the “safeguard” range recommended for dialysis patients. A similar trend for aluminum sulfate was also observed, while preliminary results for three other aluminum species, lactate, citrate, and maltol, were also reported. Although previous reports have indicated a positive effect of aluminum on mitosis in vitro or in vivo, this is the first such report involving human material. It is clear that higher concentrations of aluminum chloride at 2.0–4.0 mM reversibly inhibit mitosis while more dilute concentrations of 1–2 μM, closer to those found in normal serum, enhance mitosis. The present results, as well as those in the literature, suggest that aluminum may be an essential element in cellular processes for optimal growth, development, and health maintenance. Future research will further test this hypothesis.