Ethylene and wound-induced cyanide-resistant respiration climaxes in potato: The synergistic role of CO2 and the selective role of lycorine

When treated with ethylene in O₂, conditioned potato (Solanum tuberosum L. cv. Russet Burbank) tubers – that is, tubers kept at room temperature for 10 days or more – yield slices that are CN^? resistant. Ten % CO₂ in the gas mixture not only synergizes the effect of ethylene, but replaces the need for conditioning as well. The response to CO₂ is more pronounced with increasing time from harvest. By contrast fresh slices from untreated tubers are CN^? sensitive, as are slices from tubers incubated in O₂ or O₂ plus CO₂. The suggestion is made that CN^? resistance is constitutive, and that treatment with ethylene/CO₂ in O₂ confers on potato tuber tissue a resistance to the extensive degradation of membrane phospholipids that normally attends slicing and leads to the loss of CN^? resistance. In this connection respiration inhibition by imidazole, an inhibitor of fatty acid α-oxidation, is extensive in slices of untreated tubers, and sharply diminished in slices of ethylene-treated tubers in proportion to their CN^? resistance. The coextensive rise of respiration rate and CN^? resistance in aged potato slices has led to the presumption that the CN^?-resistant path mediates the respiration climax. Accordingly the alkaloid, lycorine, has been considered to inhibit the development of CN^? resistance in aging potato slices because it curtails the wound-induced respiration. A comparison was carried out on the effect of lycorine on CN^?-sensitive and CN^?-resistant fresh slices – the latter obtained from ethylene/CO₂-treated tubers. Lycorine suppressed the development of the wound-induced respiration without restricting the development of CN^? resistance.     

Poly(I):poly(C)-enhanced alveolar and peritoneal macrophage phagocytosis: quantification by a new method utilizing fluorescent beads

Phagocytosis is an important immune function to quantify. This immune response may be modulated by exposure to biological response modifiers or by exposure to pollutants. A new technique for quantifying nonspecific phagocytosis of alveolar and peritoneal macrophages in the same animal has been developed that utilizes fluorescent polystyrene beads. When incorporated into inhalation studies, this technique can be used to determine whether the toxic effect of an inhaled pollutant is local (effect on alveolar macrophages), systemic (effect on peritoneal macrophages), or both local and systemic. This method results in a determination of both the level of phagocytosis (the percentage of phagocytic macrophages) and the macrophage specific activity (the number of beads phagocytized per macrophage). This method also allows a determination of adherence by quantifying the number of particles in contact with, but not phagocytized by, the macrophage. Macrophage preparations were incubated with fluorescent beads for 2 hr and cyto-centrifuged onto a glass slide. Fluorescent beads present on the slide or cell-associated but not ingested by phagocytosis were removed by immersing the slide containing the macrophage preparation in methylene chloride for 15-30 sec. Fluorescent beads ingested by phagocytosis were then easily quantified with a fluorescence microscope. This technique was used to assess the baseline levels of phagocytosis for rat alveolar and peritoneal macrophages from the same animal and the kinetics and level of enhanced phagocytosis for alveolar and peritoneal macrophages after injection with the interferon inducer polyinosinate-polycytidylate (poly(I):poly(C)). The kinetics of enhanced alveolar and peritoneal macrophage phagocytosis by poly(I):poly(C) were similar; however, stimulated phagocytic levels of peritoneal macrophages never reached the phagocytic activity observed for the resident, highly phagocytic alveolar macrophages. This elevated phagocytic activity is most likely due to interferon stimulated by particulate matter in the large volume of air processed by the lungs and is important for host defense against a number of different inhaled microorganisms.     

Environmental factors influencing the vertical migration of planktonic rotifers in a hypereutrophic tarn

The diel vertical migration of planktonic rotifers in a small, hypereutrophic tarn was investigated on four occasions in 1983. When the tarn was isothermal the rotifers were distributed throughout the water column. After stratification, the rotifers were confined to the top 1–2 m of oxygenated water. On all four dates the rotifers were aggregated at specific depths in the water column. On some occasions, the pattern of aggregation changed as the animals performed distinct diurnal migrations. Keratella cochlearis, K. quadrata and Polyarthra vulgaris usually followed the reverse migrations of the phytoplankton. In contrast, the movements of Anuraeopsis fissa were less pronounced and were associated with variations in the depth of the oxycline.     

Characterization of the chicken oocyte receptor for low and very low density lipoproteins

The chicken oocyte receptor for low and very low density lipoproteins has been identified and characterized. Receptor activity present in octyl-beta-D-glucoside extracts of oocyte membranes was measured by a solid phase filtration assay, and the receptor was visualized by ligand blotting. The protein had an apparent Mr of 95,000 in sodium dodecyl sulfate-polyacrylamide gels under nonreducing conditions and exhibited high affinity for apolipoprotein B-containing lipoproteins, but not for high density lipoproteins or lipoproteins in which lysine residues had been reductively methylated. Binding of lipoproteins was sensitive to EDTA, suramin, and treatment with Pronase. In these aspects, the avian oocyte system was analogous to the mammalian low density lipoprotein receptor in somatic cells. Furthermore, a structural relationship between the mammalian and avian receptors was revealed by immunoblotting: polyclonal antibodies directed against the purified bovine low density lipoprotein receptor reacted selectively with the 95-kDa chicken receptor present in crude oocyte membrane extracts.     

Regional differences in quantities of histochemically detectable mucosubstances in nasal, paranasal, and nasopharyngeal epithelium of the bonnet monkey

Inhaled irritants induce secretory cell hyperplasia in nasal epithelium of animals. To characterize this response histochemically it is first important to know the histochemical character and distribution of epithelial mucosubstance in the normal nasal cavity. An automated image analyzing method was used to detect and quantitate acidic, neutral, and sulfated mucosubstances in the epithelium lining the nasal and paranasal airways of eight bonnet monkeys. Tissue sections 2 micron thick from defined regions of these airways were stained with either alcian blue/periodic acid-Schiff to demonstrate acid and neutral mucosubstances or high iron diamine to demonstrate sulfated mucins. Respiratory epithelium covering maxilloturbinates had the largest volume of stainable mucosubstance per unit surface area of basal lamina, whereas the maxillary sinus epithelium had the least. There was a general anteroposterior increase in the quantity of total epithelial mucosubstance along the septal and lateral walls of the nasal cavity, and there was more acidic than neutral mucosubstance in the posterior nasal airway than in the anterior. Epithelial mucosubstance in the maxillary sinus was predominantly neutral. Therefore, we conclude that there are substantial regional quantitative differences in stainable mucosubstances in the primate nasal epithelium which must be considered when examining nasal mucosa for irritant-induced changes in epithelial mucins.     

Population genetics of coagulant factor IX: frequencies of two DNA polymorphisms in five ethnic groups.

Two frequently used restriction-enzyme polymorphisms (RFLPs) of coagulant F.IX, TaqI and XmnI, have been examined in five ethnic groups: white Americans, black Americans, East Indians, Chinese, and Malays. There is a distinct "cline" in the frequencies of both polymorphisms, from white Americans to Malays. The rarer type 2 alleles of both polymorphisms, in which middle recognition sites are present--and which in our sample reach their highest frequencies in white Americans--are marginally higher in four groups of Europeans previously reported by others. The frequencies of the rarer alleles are significantly higher in Europeans than in black Americans and East Indians, and these alleles are essentially absent in Chinese and Malays. The frequency of heterozygosity diminishes in the same order, being zero in Malays for both polymorphisms. The polymorphisms are in strong linkage disequilibrium, and in all groups the type 1 allele for TaqI is disproportionately accompanied by the type 1 allele for XmnI. The paucity of type 2 alleles and the low rate of heterozygosity in four non-European groups suggest that the polymorphisms will be of little diagnostic value south of Gibraltar and east of Suez. This prediction is confirmed by the observed haplotype frequencies in the black American and the Oriental groups.     

Automation of routine clinical chromosome analysis. II. Metaphase finding

Metaphase finding is an essential activity in chromosome analysis, and there is much to gain from its automation. This paper describes software for automatic metaphase finding developed for use as part of a routine clinical chromosome analysis system, principally for samples from blood and amniotic fluid. Since the metaphase finding and analysis programs were intended to be used widely in clinical laboratories, cost and portability were important design features. The metaphase finder has been implemented on a moderately priced, general-purpose image analyzer (Magiscan 2), which controls a standard research microscope with motorized stage and focus. Metaphases are detected using fast gray-level processing on whole fields of view, followed by binary processing to produce a figure of merit for each detected object. Clinical experience has shown that this ability to rank detected objects on the basis of their suitability for analysis is a critical feature in determining the usefulness of an automatic metaphase finder.     

Influence of Nitrogen Fertilizers on Growth, Spore Production and Germination, and Biocontrol Potential of Trichoderma and Gliocladium

The mycelial weight of eight out of nine isolates of Trichoderma spp. and Gliocladium virens increased in media supplemented with 2000 mg/l of nitrogen (N) from the fertilizers NH₄Cl, NaNO₃, and a commercial 20–20–20. In general, the greatest increase in growth (up to 311 %) occurred with 20–20–20. The extent of growth was similar with either NH₄Cl or NaNO₃, but was less than that with 20–20–20. Measured by radial development on agar surfacesgrowth of isolates was either not affected or was constricted by supplemental fertilizers. Production of conidia by six out of eight isolates was stimulated by 20–20–20 but not by NH₄Cl or NaNO₃. Germination of conidia of all isolates, generally was high (> 85 %) on amended and nonamended agar. Chlamydospore formation by three Trichoderma isolates in liquid media was not affected by fertilizers. Antagonism or overgrowth of the pathogen Rhizoctonia solani by Trichoderma isolates in culture was reduced appreciably by NaNO₃, but was not affected by NH₄Cl or 20–20–20. Addition of 20–20–20 to natural soil did not reduce further the survival of R. solani caused by germling preparations of six out of seven Trichoderma isolates. However, reduction in survival of the pathogen caused by a T. hamatum isolate was stimulated further (45 %) by the fertilizer.     

Growth determinations for unattached bacteria in a contaminated aquifer.

Growth rates of unattached bacteria in groundwater contaminated with treated sewage and collected at various distances from the source of contamination were estimated by using frequency of dividing cells and tritiated-thymidine uptake and compared with growth rates obtained with unsupplemented, closed-bottle incubations. Estimates of bacterial generation times [(In 2)/mu] along a 3-km-long transect in oxygen-depleted (0.1 to 0.7 mg of dissolved oxygen liter-1) groundwater ranged from 16 h at 0.26 km downgradient from an on-land, treated-sewage outfall to 139 h at 1.6 km and correlated with bacterial abundance (r2 = 0.88 at P less than 0.001). Partitioning of assimilated thymidine into nucleic acid generally decreased with distance from the contaminant source, and one population in heavily contaminated groundwater assimilated little thymidine during a 20-h incubation. Several assumptions commonly made when frequency of dividing cells and tritiated-thymidine uptake are used were not applicable to the groundwater samples.     

Mammalian folylpoly-gamma-glutamate synthetase. 3. Specificity for folate analogues

A variety of folate analogues were synthesized to explore the specificity of the folate binding site of hog liver folylpolyglutamate synthetase and the requirements for catalysis. Modifications of the internal and terminal glutamate moieties of folate cause large drops in on rates and/or affinity for the protein. The only exceptions are glutamine, homocysteate, and ornithine analogues, indicating a less stringent specificity around the delta-carbon of glutamate. It is proposed that initial folate binding to the enzyme involves low-affinity interactions at a pterin and a glutamate site and that the first glutamate bound is the internal residue adjacent to the benzoyl group. Processive movement of the polyglutamate chain through the glutamate site and a possible conformational change in the protein when the terminal residue is bound would result in tight binding and would position the gamma-carboxyl of the terminal glutamate in the correct position for catalysis. Steric limitations imposed on the internal glutamate residues that loop out and additional steric constraints imposed by binding of different pterin moieties would be expected to effect slight conformational changes in the protein and/or the terminal glutamate and would explain the decrease in on rate and catalytic rate with increased polyglutamate chain length, and the differential effect of one-carbon substitution on the catalytic rate with polyglutamate derivatives. The 4-amino substitution of folate increases the on rate for monoglutamate derivatives but severely impairs catalysis with diglutamate derivatives. Pteroylornithine derivatives are the first potent and specific inhibitors of folylpolyglutamate synthetase to be identified and may act as analogues of reaction intermediates.(ABSTRACT TRUNCATED AT 250 WORDS)