Origin of bombesin-like peptides in human fetal lung

Four different forms of bombesin-like immunoreactive peaks were detected in extracts of human fetal lung by the use of reversed-phase high performance liquid chromatography (HPLC). Peaks I, II, III and IV, (increasing retention time), were eluted using a 14-38% of acetonitrile gradient containing 0.1% trifluoroacetic acid (TFA). Peak II was the major material found in the extract of human fetal lung obtained at 16-20 weeks gestation. None of the four compounds contained in the eluted peaks had the same retention time as amphibian bombesin or porcine gastrin releasing peptide (GRP). On reversed-phase HPLC using two different solvent systems TFA or heptafluorobutyric acid (HFBA) as a hydrophobic counter ion, and in gel filtration chromatography, the chromatographic behavior of the main peak (peak II) was the same as that of the carboxyl terminal fragments of GRP, GRP18-27 or GRP19-27. This suggested that the peptide(s) in peak II resembled in composition the carboxy terminal 9 or 10 amino acids of porcine GRP. Following tryptic digestion the material in peak IV was converted to the more polar compound present in peak II. Two other peptide peaks were eluted close to peak II and these were presumed to be a modification of this main peak. One of the possible biosynthetic steps in the formation of bombesin-like peptides in human fetal lung could be a tryptic conversion of a less polar peptide to a more polar form (peak IV to II).     

Nucleic acids in mummified plant seeds: screening of twelve specimens by gel-electrophoresis,molecular hybridization and DNA cloning

Summary Twelve seed specimens of varying ages and from different archaeological sites were analyzed for the presence of polymerized DNA and RNA. Amongst the samples tested, one of Vitis vinifera from an archaeological site in Iran (2,000–3,000 B.C.) was found to be completely devoid of nucleic acids. Zea mais seeds of Precolumbial age from Peru (about 800 A.D.) contained depolymerized DNA and RNA. Samples of Vitis vinifera and Rubus sp. from a Lombard archaeological site (800 A.D.) as well as radiocarbon dated seeds from the site of the Spring Sanctuary near Metaponto (I–IV century B.C.) were found to contain polymerized DNA and rRNA bands. However the electrophoretic properties of the rRNAs in one case and hybridization experiments performed with cloned seed DNA in the other, clearly demonstrated that the polymerized nucleic acids were not of plant origin.     

Photoinhibition of white clover seed germination at low water potential

Photosensitivity of germination of white clover ( Trifolium repens L. cv. Podkowa) seeds was studied under water deficit (low water potential) conditions at 25°C. The seeds showed negative photoblastism, which was most pronounced at -0.03 MPa polyethylene glycol solution. Inhibition was observed at two different wavelength bands with maxima at 660 nm (R) and around 730 nm (FR). Red light acted identically to white light (maximum inhibition ca 50%). The effect of far-red illumination was less inhibitory (20–30%). The photoresponse required long illuminations (3 h exposures); saturation level was at 0.1 W m⁻², independently of the light quality. White clover seed germination showed no reversibility of the effects of R and FR light. Prolonged illumination with R and FR increased the inhibition, and intermittent illumination had a higher effect than a continuous one. It was concluded that the photoinhibition of germination of seeds of Trifolium repens involves a reaction dependent on the rate of phytochrome interconversion, a property that is characteristic for the high irradiance reaction.     

Artificial seeds in barley: encapsulation of microspore-derived embryos

Summary An in vitro culture system has been developed for barley (Hordeum vulgare), which yields high frequencies of high quality microspore-derived embryos without an intervening callus phase. The embryos are very similar to zygotic embryos with regard to their morphology and germination capacity. These embryos were encapsulated in sodium alginate to produce individual beads containing one embryo each. In accordance with the literature, these beads are denoted artificial seeds. The artificial seeds germinated well and with a root system superior to that of non-encapsulated embryos. The artificial seeds also maintained their germination capacity for at least 6 months, whereas non-encapsulated embryos did not survive more than 2 weeks in storage. Artificial seeds, thus, probably provide a simple and universal delivery system of in vitro plantlets to greenhouse or field.     

Survey of the mycoflora and mycotoxins of cotton seeds and cotton seed products in Egypt

Thirty-nine species and 16 fungal genera were isolated from Egyptian cotton seeds, cotton seed meal and cotton seed cake on 1% glucose-Czapek's agar medium incubated at 28 °C. Aspergillus was the most frequent genus and it emerged in 87–100% of the samples contributing 70–98% of total fungi in the three substrates tested. The most common species were A. niger, A. flavus, A. fumigatus, A. terreus and Rhizopus stolonifer; A. niger, A. fumigatus and Penicillium corylophilum; and A. niger, A. flavus, A. terreus, A. nidulans and Rhizopus stolonifer, respectively. Cotton seeds and cotton seed products were naturally contaminated by aflatoxin B₁ and B₂. About 16% of the different substrates tested were positive for aflatoxin contamination. No citrinin, ochratoxin A, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin or zearalenone were detected in the samples assayed.     

Induction of secondary dormancy in sunflower seeds by high temperature. Possible involvement of ethylene biosynthesis

High temperature (45°C) inhibits seed germinition and seedling sunflower ( Helianthus annuus L. cv. Mirasol). Treatment of imbibed seeds at 45°C for more than 48 h induces a secondary dormancy, which is associated with progressive decrease of germination ability at optimal temperature (25°C) as well as with abnormal seedling growth. Ethylene (55μl l⁻¹) and 2-chloroethylphosphonic acid (ethephon) (2.5 m M ) improve germination of thermodormant seeds at 25°C. but the abnormal growth of the seedlings remains. O₂-enriched atmosphere and dry storage improve germination and normal seedling growth. The induction of thermodormancy in sunflower seeds seems associated with loss of their ability to convert 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. Possible effects of high temperature on membranes and ethylene forming enzyme (EFE) are discussed.     

Population density ofMonochamus alternatus adults (Coleoptera: Cerambycidae) and incidence of pine wilt disease caused byBursaphelenchus xylophilus (Nematoda: Aphelenchoididae)

Summary The seasonal occurrence ofMonochamus alternatus and newly weakened trees were investigated in aPinus thunbergii stand for 4 years. Adult beetles were present between June and September with a peak in their population occurring in early July followed by a decline then a period of about one month being in a steady number. The average number ofBursaphelenchus xylophilus (Nematoda), which is the causal agent of pine wilt disease, within beetles decreased as the season advanced. Pine trees newly weakened byB. xylophilus appeared between June and October, especially from August to October. The proportion of weakened or killed trees was directly proportional to the average beetle density per tree from June to August.     

Buried seed population in the herbaceous lomas on Loma Ancon in the coastal desert of central Peru

Herbaceous lomas in the Peruvian coastal desert, of South America establish in spring, and its habitat is limited to the southern or southwestern slopes along the coast that are affected by thick fog. The time of appearance, the duration and the thickness of the fog vary greatly from year to year, so the lomas can grow only in habitats with enough water to, sustain seed germination and plant growth. This paper studies the species composition and density of the buried seed population, of the herbaceous lomas of Loma Ancon in order to clarify the mechanisms of the lomas' establishment. The mean number of species with viable seeds was about, 12 spp. m⁻² and that of dead seeds was about 22 spp. m⁻². The dominant species wereSolanum tuberiferum, S. pinnatifidum andNolana humifusa, both in viable and dead seeds. Viable seed density was about 5000–8000 seeds m⁻², which is comparable with the seed densities of other herbaceous communities. Dead seed density was about 15000–27000 seeds m⁻², or nearly three times the viable seed density, because the rate of decomposition was slow in the extremely dry conditions. The net increase of viable seeds by seed production was estimated at about 5000 seeds m⁻² in 1980, and the increase in the number of dead seeds was 2200 seeds m⁻².     

Physiological and enzymatic activity of pepper seeds (Capsicum annuum) during priming

Pepper ( Capsicum annuum L. cv. Keystone Resistance Giant 3) seeds were monitored during priming to determine if seed treatments which accelerate the rate of germination could be correlated with specific physiological changes within the seeds. Pepper seeds primed with −0.90 and −1.35 MPa NaCl solutions at 23°C for 18 days did not completely equilibrate with the osmotic potential of the priming solution. Seed respiratory rates indicated that priming extends the lag phase of germination following imbibition. Soluble protein levels increased 115% in primed seeds, and the uptake and incorporation of [¹⁴C(U)] labelled amino acids into the acid insoluble fraction increased throughout the priming treatments. Alcohol dehydrogenase (EC 1.1.1.1, anaerobic metabolism), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44, pentose phosphate pathway) activities remained stable throughout the priming treatment, but were higher after 6 days. than the water-imbibed controls. Aldolase (EC 4.2.1.1. glycolysis) and isocitrate lyase (EC 4.1.3.1, glyoxylate cycle) activities increased with imbibition and were 61 and 56% (respectively) higher in primed seeds as compared to the water-imbibed controls after 12 days. Treatment with the −0.90 MPa NaCl solution was more effective than the −1.35 MPa solution in improving the rate of germination, yet there were no significant differences between the protein concentrations or enzyme activities of the two priming treatments. However, the incorporation of labelled amino acids into pepper seeds was significantly higher in the −0.90 MPa priming treatment.