Pea lectin is correctly processed,stable and active in leaves of transgenic potato plants

A gene encoding the preproprotein of the pea (Pisum sativum) lectin was expressed in transgenic potato plants using a cauliflower mosaic virus (CaMV) 35S promoter or a tobacco ribulose bisphosphate carboxylase small subunit (ssRubisco) promoter. Presence of the pea lectin to levels greater than 1% of total soluble leaf protein was detected by radioimmunoassay (RIA). The pattern of expression derived from the two promoters was established using both RIA and a squash-blot immunolocalisation technique. Western blotting demonstrated that the preproprotein was correctly processed, generating and subunits that assembled to give an isolectin form observed in pea seeds and roots. It was also found that the haemagglutination activity and specificity of pea lectin synthesised in transgenic potato leaves was comparable to purified lectin from pea cotyledons.     

Control of early seedling growth in varietal lines of hexaploid wheat (Triticum aestivum), durum wheat (Triticum durum), and barley (Hordeum vulgare) in response to the phthalimide growth regulant,AC 94,377

AC 94,377 caused elongation of seedlings of Triticum aestivum, Triticum durum, and Hordeum vulgare when applied to the soil, or the soil plus seed at planting. Affected were the leaf sheathes and the coleoptiles, and at high compound rates there was premature elongation of the stem internodes. As exemplified by the response of T. aestivum var. Fidel, the influence on coleoptile elongation was greatest under conditions whereby the coleoptile was naturally stimulated to elongate, i.e., when growth was in the dark and temperatures were cool (15°C). All of the stem internodes were capable of elongation except the one below the coleoptile node. The effect on leaf sheath elongation was prolonged when compared to activity of gibberellic acid.Several varieties of the three cereal species were examined in the greenhouse for sensitivity to AC 94,377 in order to evaluate the extent of the response. All of the barley varieties examined were sensitive to AC 94,377, elongating regardless of the planting conditions. Two such conditions were established, including incubation under warm (28/20°C) conditions following planting the grains 1 cm deep, and incubation under cool (22/16°C) conditions following planting the grains 6 cm deep. Wheat varieties distributed into two general categories, those which were sensitive and those which were not. The insensitivity correlated well to the presence of the reduced height (Rht) and GA-insensitive (Gai) genes in Triticum aestivum and Triticum durum, respectively. Thus, AC 94,377 can be used conveniently to evaluate varietal lines for the presence of this phenotype. This correlation also lends support to the notion that the Rht/Gai mutations in wheat are either at the level of a gibberellin receptor or at a step in the signal transduction pathway.     

Nuclear genome characterization of the carrageenophyteAgardhiella subulata (Rhodophyta)

DNA reassociation kinetics were used to determine nuclear genome organization and complexity inAgardhiella subulata (Gigartinales, Rhodophyta). Results indicate the presence of three second-order components corresponding to fast (22%), intermediate (68%) and slow (10%) fractions. Thus, the genome consists of 90% repetitive sequences. Microspectrophotoometry with the DNA-localizing fluorochrome DAPI was used to confirm ploidy level differences in the gametophytic and tetrasporophytic phases. Results indicate that meiosis occurs during tetrasporogenesis. Comparison of mean nuclear DNA (I_f) values to chicken erythrocytes (RBC) resulted in an estimate of 0.9 pg/2C genome forAgardhiella. Karyological studies using aceto-orcein revealed a chromosome complement of 2N = 44 in carposporangia and the presence of 22 bivalents during diakinesis of tetraspore mother cells.     

Structure of equine corticotropin releasing factor

A 41 amino acid peptide, probably identical in structure to human corticotropin releasing factor, was isolated from 70 equine hypothalami by methanol extraction, immunoaffinity chromatography and single step of reverse phase HPLC. The amino acid sequence was determined by gas phase sequence analysis. Probable carboxyl terminal amidation was demonstrated by similar retention times for equine and human corticotropin releasing factor on reverse phase HPLC at pH 8. The likely structure of equine corticotropin releasing factor is: Ser-Glu-Glu-Pro-Pro- Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Ala-Arg-Ala-Glu-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn- Arg-Lys-Leu-Met-Glu-Ile-Ile-NH₂. The purified peptide is equipotent with human corticotropin releasing factor in an in vitro bioassay and in a human plasma binding protein assay.     

The respiratory response to heat shock in Neurospora crassa

A sharp decrease in oxygen uptake occurred in Neurospora crassa cells that were transferred from 30 degrees C to 45 degrees C, and the respiration that resumed later at 45 degrees C was cyanide-insensitive. Energization of mitochondria, measured in vivo with fluorescence microscopy and a carbocyanine dye, also declined sharply in cells at 45 degrees C. Electron microscopy showed no changes in mitochondrial complexity; however, the cytoplasm of heat-shocked cells was deficient in glycogen granules.     

The association between amount of red muscle and mobility in fishes: A statistical evaluation

Synopsis It is commonly accepted that more active fishes have a greater proportion of red muscle in their trunk musculature than do less active fishes. Further, the proportion of red muscle has been used to classify fish species into functional groups reflecting different activity patterns. Nevertheless, existing measures of both red muscle and mobility have several limitations, and the relationship between these parameters has never been evaluated quantitatively. Using data from the literature, we demonstrate a positive, statistical association between the proportion of red muscle in the caudal peduncle of marine fishes and a qualitative measure of mobility (categorization as sedentary vs. mobile based on natural-history accounts). Analyses of the frequency distribution of the proportion of red muscle also provide evidence for two subdistributions. However, this bimodality does not correspond with sedentary vs. mobile or sit-and-wait vs. active search dichotomies.     

Phaseolin variability among wild and cultivated common beans (Phaseolus vulgaris) from Colombia

Phaseolin seed protein variability in a group of 8 wild and 77 cultivated common bean (Phaseolus vulgaris) accessions was determined using 1-dimensional SDS/ PAGE and 2-dimensional IEF-SDS/PAGE. Wild common bean accessions exhibited the 'CH' and 'B' patterns, previously undescribed among either wild or cultivated common beans. The cultivated genotypes showed (in decreasing frequency) the previously described 'S,' T,' and 'C phaseolin patterns as well as the new 'B' pattern similar to the pattern identified in a Colombian wild common bean accession. In the northeastern part of the Colombian bean-growing region, the cultivars exhibited almost exclusively an 'S' phaseolin type, while in the south-western part, the 'T' and 'C phaseolin cultivars were more frequent. Seed size analysis indicated that 'T' and 'C' phaseolin cultivars had larger seeds than 'S' and 'B' phaseolin cultivars. Our results suggest that Colombia is a meeting place for Andean and Middle American common bean germplasms, as well as a domestication center for the common bean.     

Distribution of Hydrogen-Metabolizing Bacteria in Alfalfa Field Soil

H₂ evolved by alfalfa root nodules during the process of N₂ fixation may be an important factor influencing the distribution of soil bacteria. To test this hypothesis under field conditions, over 700 bacterial isolates were obtained from fallow soil or from the 3-mm layer of soil surrounding alfalfa (Medicago sativa L.) root nodules, alfalfa roots, or bindweed (Convolvulus arvensis L.) roots. Bacteria were isolated under either aerobic or microaerophilic conditions and were tested for their capacity to metabolize H₂. Isolates showing net H₂ uptake and ³H₂ incorporation activity under laboratory conditions were assigned a Hup⁺ phenotype, whereas organisms with significant H₂ output capacity were designated as a Hout⁺ phenotype. Under aerobic isolation conditions two Hup⁺ isolates were obtained, whereas under microaerophilic conditions five Hup⁺ and two Hout⁺ isolates were found. The nine isolates differed on the basis of 24 standard bacteriological characteristics or fatty acid composition. Five of the nine organisms were isolated from soil around root nodules, whereas the other four were found distributed among the other three soil environments. On the basis of the microaerophilic isolations, 4.8% of the total procaryotic isolates from soil around root nodules were capable of oxidizing H₂, and 1.2% could produce H₂. Two of the Hup⁺ isolates were identified as Rhizobium meliloti by root nodulation tests, but the fact that none of the isolates reduced C₂H₂ under the assay conditions suggested that the H₂ metabolism traits were associated with various hydrogenase systems rather than with nitrogenase activity. Results from this study support the concept that H₂ evolution by alfalfa root nodules has a significant effect on the surrounding microenvironment and influences the number and diversity of bacteria occupying that region.