Global temperature stability by rule induction: An interdisciplinary bridge

Rules incorporating influences on global temperature, an estimate of radiation balance, were induced from astronomical, geophysical, and anthropogenic variables. During periods of intermediate global temperatures (generally like the present century), the influences assume cancelingroles; influences cancel the effects of extreme states potentially imposed by other influences because they are, in aggregate, most likely to be assuming opposite values. This imparts an overall stability to the global temperature. To achieve cold or hot global temperature, influences assume reinforcingroles. CO ₂ is an active influence on global temperature. By virtue of its constancy in the atmosphere, it can be expected to sponsor frequent hot years in combination with the other influences as they cycle through their periods. If measures were implemented to maintain warm or cool global temperatures, it could retain the status quoof present global agricultural regions. They are probably more productive than hot world regions would be because of narrow storm tracks.     

Stimulatory Effect of Histamine on Cyclic AMP Formation in Chick Pineal Gland

Abstract: Histamine (HA) potently stimulated cyclic AMP accumulation in intact pineal glands taken from light-exposed chicks. The action of HA was stronger in the presence of forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). The effect of HA was mimicked by HA H₁- and H₂-receptor-selective agonists in the following order of potency: HA > 4-methylhistamine (H₂) > 2-methylhistamine (H₁) > 2-thiazolylethylamine (H₁) ≫ dimaprit (H₂). The HA H₃-receptor-selective agonist (R)α-methylhistamine was poorly active. The effect of HA was antagonized by selective H₂-receptor blockers (tiotidine > oxmetidine > cimetidine = ranitidine) and was not significantly affected by the selective H₁- and H₃-receptor blockers mepyramine and thioperamide. A detailed analysis of an antagonistic action of ranitidine (versus HA) revealed a noncompetitive mode of action of the H₂ blocker. The stimulatory action of the H₁ agonist 2-thiazolylethylamine (both under basal conditions and in the presence of forskolin or IBMX) was not significantly influenced by three H₁-receptor-selective blockers (mepyramine, triprolidine, and diphenhydramine), but it was totally counteracted by ranitidine. Using accepted selective agonists and antagonists of the HA H₁, H₂, and H₃ receptor we were unable to identify clearly the receptor subtype mediating the HA action on the cyclic AMP-generating system of the chick pineal. It is suggested that the receptor under consideration may represent either an H₂-like (in terms of mammalian criteria) or avian-specific HA receptor. The data suggest that HA may be considered a modulator of the pineal activity in chicks.     

Accumulation of cesium and radiocesium in forest litter in selected regions of poland and its influence on litter-to-mushroom transfer factor

The aim of this work was to check whether the stable cesium content in forest litter affects the value of radiocesium from litter-to-mushroom transfer factorTf or not. Total cesium in litter, measured by AAS, varied from 0.1–2.7 μg/g. These data, combined with earlier results for mushrooms, showed no simple correlation forTf. More complex relationships provided very high correlation coefficients, but their validity needs further investigation.     

High fidelity extrachromosomal recombination and gene targeting in plants

The precision of extrachromosomal homologous recombination and gene targeting in plant cells was investigated. Recombination was directed to introns of selectable marker genes where potential changes could persist without affecting the function and therefore the selectability of the genes. Approximately 9 kb of crossover regions was rescued and sequenced. Changes were detected at a frequency below one point mutation per 1000 bp, indicating that extrachromosomal recombination and gene targeting both appear to occur with high fidelity.     

A minichromosome-like structure in wheat embryos

A crude nuclear fraction of resting wheat embryos was used as the source of putative plant minichromosomes: unique DNA sequences the size of genes and flanked by telomere-type repeats. Preliminary separation of low-molecular-weight DNA species from chromosomal DNA (Hirt's method), velocity sedimentation, and isopycnic centrifugation were followed by PCR amplification of minichromosome-like sequences. The most abundant PCR product was cloned and sequenced. In addition to telomeric repeats (defined by a PCR primer), which were the expected sequences, the linear DNA molecule (637 pb) contained an ARS-like element, RAP1-binding site, and two relatively long ORFs. The whole sequence seems to represent a naturally occurring plant minichromosome.     

The Role of Cellular and Extracellular Matrix Adhesion Proteins in Organ Transplantation

The specific adhesion of cells to other cells or to particular tissue microenvirorvments is a basic function of cell migration and recognition, and underlines many biologic processes including embryogenesis, repair and immunity. Leukocytes express an array of surface receptors broadly known as “accessory adhesion molecules.” which mediate most cell -cell interactions, direct lymphocyte traffic between anatomical compartments, and facilitate cellular adhesion to the inflammation or alloantigenic sites (Springer 1990). In addition, adhesion molecules are involved in the process of antigen recognition, and may costimulate cell activation and transformation. These proteins are thought to affect the very early antigen independent events between host leukocytes and vascular endothelium. Because of these activities, the subject of adhesion molecules is gaining interest in the field of organ transplantation, in both conceptualization and development of novel therapeutic strategies (de Sousa et al. 1991, Kupiec-Weglinski et al. 1993a, Heemann et al. 1993).     

Chromosomal localization of four human zinc finger cDNAs

cDNA clones encoding zinc finger motifs were isolated by screening human placenta and T-cell (Peer) cDNA libraries with zinc finger (ZNF) consensus sequences. Unique cDNA clones were mapped in the human genome by rodent-human somatic cell hybrid analysis and in some cases in situ chromosomal hybridization. ZNF 80 mapped to 3p12-3qter, ZNF 7 was previously mapped to 8q24 and is here shown by in situ hybridization and use of appropriate hybrids to map telomeric to the MYC locus. ZNF 79 mapped to 9q34 centromeric to the ABL gene and between a constitutional chromosomal translocation on the centromeric side and the CML specific ABL translocation on the telomeric side. ZNF77 mapped to 19p while ZNF 78L1 (pT3) mapped to 19q. Chromosome 19 carries many ZNF loci and other genes with zinc finger encoding motifs; the pT3 clone additionally detected a locus designated ZNF 78L2, which mapped to chromosome region 1p, most likely in the region 1p32 where the MYCL and JUN loci map.     

DNA fingerprinting of red clover (Trifolium pratense L.) with Jeffrey's probes: detection of somaclonal variation and other applications

Summary DNA fingerprints generated by the Jeffreys' probes, 33.6 and 33.15, indicated the presence of minisatellite-like sequences in the red clover genome. The fingerprints generated by probe 33.6 gave less background and fewer but better defined bands than those obtained with probe 33.15. Assay of a regenerative somaclonal variant (F49R) by DNA fingerprinting with probe 33.6 detected mutation that was unlinked to the regenerative trait. The fingerprints obtained under the applied conditions also demonstrated genetic stability of consecutive generations of the regenerants in tissue culture. DNA fingerprints of F₁ plants revealed that each polymorphic band was inherited from either one or the other parent. Both probes distinguished individual-specific genotypes in seven cultivars of red clover. Greater variability in DNA fingerprints was detected between (V=0.899) than within (0.417≤V≤0.548) cultivars.     

Spatial patterns of trees in natural forests of East-Central Europe

The analysis of spatial patterns is one of the ways to estimate the role of competition among trees in forest dynamics. Three hypotheses concerning distribution patterns in old-growth stands were tested: (1) fine-scale spatial patterns of trees are regular; (2) patterns do not differ significantly from a random distribution, and (3) spatial patterns at larger scales are clumped because of site heterogeneity. Old-growth forest stands in Poland and the Czech Republic were analysed with a modified Ripley K function, using distribution maps of tree stems. Fine-scale spatial patterns (with distances among trees not exceeding 15 m) were usually intermediate between random and regular. Trends towards a regular distribution occurred more often among dead than among live individuals. No significant relationships between tree species were found at smaller scales; however, at larger scales (distances from 15–25 m) negative associations between some species were found. This reflects site heterogeneity rather than any direct influence of one tree species upon another.     

Phytochemistry and pharmacology of sea buckthorn (Elaeagnus rhamnoides; syn. Hippophae rhamnoides): progress from 2010 to 2021

Phytochemistry Reviews - Sea buckthorn (Elaeagnus rhamnoides; syn. Hippophae rhamnoides) is a thorny shrub or a small tree belonging to the Elaeagnaceae family, native to Eurasia. Sea buckthorn...