Spatial distribution and mortality process ofAnoplophora malasiaca (Coleoptera: Cerambycidae) eggs in citrus groves

The study was carried out in two (A and B) citrus groves to clarify the spatial distribution patterns of eggs and larvae, and to analyse the mortality process of eggs. From the analysis by using the mean density and the mean crowding, it was clarified that the distributions of eggs were contagious and that larvae were more contagiously distributed than eggs. The τ and z indices showed that the operation of egg mortality was inversely density-dependent in both groves, and that the degree of inverse density-dependence was greater in A than in B grove. The spatial correlations between the emergence holes and the eggs or larvae in each tree, which were analysed by using ω index, showed that the distributions were more overlapping between the emergence holes and the larvae than the eggs. As the result of dividing trees into several groups according to the number of emergence holes, it was clarified that the survival rates of eggs were positively correlated with the number of emergence holes. In conclusion, inversely density-dependent mortality process was considered to be caused by lower mortality rates of eggs in the trees with more emergence holes. Especially in A grove, because the trees with more emergence holes were larger in diameter and more egg oviposition, the inversely density-dependent mortality process was considered to be detected more conspicuously than in B grove.     

Aggregation of hemoglobin S modified by bifunctional imidoesters

Sickle hemoglobin (Hb S) was cross-linked by two types of bifunctional imidoesters, dimethyladipimidate (DMA) and dimethyl-3,3'-dithiobispropionimidate (DTBP). These modified hemoglobins were separated into monomer, dimer and polymer fractions by gel filtration. All of these modified hemoglobins showed extremely left-shifted oxygen equilibrium curves with no cooperativity. The stabilities of these hemoglobins were also decreased. The solubilities of these modified hemoglobins in high-phosphate buffers were lower than those of native Hb S. Studies on the kinetics of the aggregation of these modified hemoglobins showed that intracross-linked Hb S with DMA and DTBP (DMA- and DTBP-modified monomeric Hb S) still retained the capability of aggregation with a delay time, while intercross-linked Hb S with DMA and DTBP (DMA- and DTBP-modified oligomeric Hb S) aggregated without a delay time. When the kinetics of aggregation was measured for mixtures of modified and native deoxy-Hb S, DMA-modified monomeric deoxy-Hb S shortened the delay time prior to aggregation of native deoxy-Hb S. The other modified deoxy-Hb S did not affect the delay time, suggesting that these modified oligomeric hemoglobins neither participate in the formation of nuclei nor copolymerize with native deoxy-Hb S.     

A model for chromatin opening: stimulation of topoisomerase II and restriction enzyme cleavage of chromatin by distamycin.

Histone H1 preferentially and cooperatively binds scaffold-associated regions (SARs) in vitro via specific interactions with the numerous short A + T-rich tracts (A-tracts) contained in these sequences. Selective titration of A-tracts by the oligopeptide distamycin abolishes this interaction and results in a redistribution of H1. Similarly, treatment of intact cells and isolated nuclei with distamycin specifically enhances cleavage of internucleosomal linkers of SARs by topoisomerase II and restriction enzymes. The increased accessibility of these linkers is thought to result from the unfolding (or opening) of the chromatin fiber and to be due to a reduced occupancy by histone H1. Chromatin extraction and H1 assembly experiments support this view. We discuss a model whereby open, H1-depleted chromatin regions may be generated by titration of A-tracts by putative distamycin analogues; this local opening may spread to adjacent regions assuming highly cooperative H1-H1 interactions in chromatin.     

Copolymerization of pNcollagen III and collagen I. pNcollagen III decreases the rate of incorporation of collagen I into fibrils, the amount of collagen I incorporated, and the diameter of the fibrils formed

Previous observations suggested that pNcollagen III, the partially processed form of type III procollagen, coats fibrils of collagen I and thereby helps regulate the diameter of fibrils formed by collagen I. The previous observations, however, did not exclude the possibility that pNcollagen III was deposited on preformed collagen I fibrils after the fibrils were assembled. Here, mixtures of pNcollagen III and collagen I were generated simultaneously by enzymatic cleavage of precursor forms of the proteins. The results demonstrated that pNcollagen III forms true copolymers with collagen I. The presence of pNcollagen III both inhibited the rate at which collagen I assembled into fibrils and decreased the amount of collagen I incorporated into fibrils at steady-state equilibrium. In addition, the results demonstrated that copolymerization of pNcollagen III with collagen I generated fibrils that were thinner than fibrils generated under the same conditions from collagen I alone. Increasing the initial molar ratio of pNcollagen III to collagen I in the solution-phase increased the amount of pNcollagen III copolymerizing with collagen I and progressively decreased the diameter of the fibrils. Therefore, the copolymers were heterogeneous in that the stoichiometry of the two monomers in the fibrils varied. The results are consistent with a model in which pNcollagen III can regulate the diameter of collagen I fibrils by coating the surface of the fibrils and thereby allow tip growth but not lateral growth of the fibrils.     

Parathyroid hormone-related protein is a possible autocrine growth inhibitor for lymphocytes

Adult T-cell leukemia (ATL)-related cells have the ability to produce a newly-isolated calcium-regulating protein, parathyroid hormone-related protein (PTHrP). The present study revealed that lectin-stimulated normal lymphocytes produce immunoreactive (IR)-PTHrP. When the T-cell-enriched fraction was purified from normal lymphocytes and then treated with lectin, a similar amount of IR-PTHrP was detected, suggesting that IR-PTHrP is an actual product of T-lymphocytes. A biologically active fragment of PTHrP, PTHrP(1-34), suppressed DNA synthesis in lectin-stimulated lymphocytes at concentrations greater than 50 pg/mL; the same concentration range of IR-PTHrP detected in the cultured media of lectin-stimulated lymphocytes. Therefore, it is reasonable to postulate that PTHrP is a cytokine inhibiting the cellular growth of normal lymphocytes.     

Effects of chair restraint on plasma enzyme values in the rhesus monkey (Macaca mulatta)

The purpose of this paper was to examine the effect of chair restraint on plasma enzyme values in the rhesus monkey. Six monkeys were restrained to the monkey chair for eight hours. Creatine phosphokinase (CK) value increased significantly three hours after the onset of restraint and LDH value did eight hours after the onset of restraint. The increase in CK, GOT and GPT values continued for 1 or 2 days after the release from restraint. On the other hand, these plasma enzyme values in non-restraint monkeys showed almost no changes. These results indicate that it is necessary to establish a proper method for the adjustment to chair restraint in the rhesus monkey.     

Comparison of an antiviral activity of recombinant consensus interferon with recombinant interferon-alpha-2b

To avoid possible uncertainty in comparing biological activities of interferon samples from different sources where interferon concentrations were determined independently, we prepared chromatographically pure preparations of consensus interferon and interferon-alpha-2b (one of the two commercially available recombinant alpha interferons). We revealed that consensus interferon has a stronger antiviral activity than interferon-alpha-2b, although the effects of these two recombinant interferons on the cellular macromolecule synthesis are at similar levels.