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.     

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.     

Three-dimensional reconstruction of a human metaphase chromosome from electron micrographs

A complete human metaphase chromosome has been reconstructed from a series of electron microscopical projections obtained by tilting the specimen stage at 3 degree intervals from –60 to +60 degrees. The reconstructed structure is about 3.0 m long, 1.6 m wide, and 0.8 m thick. The mass distribution was fairly homogeneous within the chromatids and neither a hollow nor a dense core was observed. The distribution and course of fibers observed are most consistent with a looping model of chromosome structure.     

Immunochemical specificity of antisera raised against the synthetic encephalitogenic peptide SH624, residues 59–74 of the myelin basic protein

Synthetic peptide SH624 (SHHPARTAHYGSLPQK), residues 59–74 of human myelin basic protein (MBP) was found to be encephalitogenic in the rabbit. Four antisera raised, against the peptide were employed in a liquid-phase equilibrium competitive radioimmunoassay with a series of synthetic peptide analogs of the region to probe the structural requirements of the B-cell determinant subsumed within SH624. The cross-reactivities of the four antisera with intact MBP were also examined. Immunochemical analyses of the four antisera suggested specificities directed against a conformational determinant dependent upon residues from the more phylogenetically conserved carboxyl C-terminal region, residues 65–74 (TAHYGSLPQK) of the synthetic immunogen. Peptide analogs shorter than SH624 from the C-terminal end showed no cross-reactivity with any of the reagent antisera while analogs shorter from the N-terminal end and including the encephalitogenic sequence TTHYGSLPQK, as well as, HYGSLPQK were reactive under equilibrium competitive conditions. SH624-reactive antibodies, cross-reactive with purified heterologous MBPs from 10 different species were also identified in all four reagent antisera. The results of these experiments support previous investigations demonstrating the accessibility of the encephalitogenic 65–74 region in intact MBP. They also underscore the importance of B-cell recognition of organ specific antigenic determinants with respect to MBP immunology and, in particular, the recognition of autoreactive determinants in the neighborhood of encephalitogenic centers.     

The “ricochet effect” and prey capture in colonial spiders

Summary Increased prey capture efficiency in colonial spiders is a consequence of the ricochet effect, as prey are captured after they bounce off several webs in succession. In this study, the prey capture of three species of colonial spiders in the genus Metepeira from Mexico are compared. These species, from different habitats, show varying levels of social organization (group size and withingroup spacing) that affect prey capture from ricochets. Metepeira sp. a (a presumed new species tentatively named atascadero) from desert grassland habitats, occur solitarily or in small groups, and gain little from prey ricochets: prey capture rates are low and variance in prey captured/spider is high. M. spinipes, from mesic agricultural sites, occur in groups of 10–150, and show a ricochet effect resulting in more and larger prey, and reduced variance in capture rate. M. incrassata, from tropical rainforest/agricultural sites, occur in large colonies of hundreds to thousands of individuals, and show a similar ricochet effect. The ricochet effect does not influence taxonomic composition of prey in either M. atascadero or M. spinipes, but does in tropical M. incrassata. This result, however, is primarily due to the capacity of certain taxa (eg., Lepidoptera), more common in the tropics, to escape more easily from spider webs. A comparison of prey capture efficiency of colonial M. incrassata with that of solitary M. atascadero shows that the ricochet effect provides an increase in efficiency across all size classes of prey.     

Neuropeptide gene expression and neural activity: Assessing a working hypothesis in nucleus caudalis and dorsal horn neurons expressing preproenkephalin and preprodynorphin

1. The working hypothesis that neuropeptide gene expression in a neuron is an indicator of that neuron's physiological activity is discussed. 2. Representative examples from the literature are presented to support the hypothesis. 3. Further, we discuss the regulation of expression of two opioid peptides, preproenkephalin and preprodynorphin, in laminae I and II of the spinal cord and in nucleus caudalis of the trigeminal nuclear complex, where they may play a role in pain modulation. 4. The expression of the opioid peptide genes can be induced by both painful and nonnoxious stimuli in neurons in time-dependent and sensory-specific fashions.