The facultative photoperiodic response in the reproductive development of Amaranthus retroflexus L.: Changes in the dose response during ontogeny

The first inductive (short-day; SD) cycle advanced the initiation of reproductive development, while additional SD cycles progressively reduced the lag phase between the start of induction and initiation. The sensitivity to SD increased during ontogeny in long-days (LD) until even the requirement for the first SD cycle disappeared at the onset of autonomous flowering. In photo-induced plants, the postinitiation rate of elongation of the apex was accelerated as the SD dose was increased, but was progressively slower as the start of induction was delayed closer to autonomous flowering, approaching asymptotically the rate of non-induced controls. The inflorescences were branched in plants growing continuously in LD and unbranched in those growing continously in SD. The subsequent branching of the inflorescence could be repressed by SD at any time prior to autonomous flowering, and the degree of repression increased with the induction dose. After the initial SD cycle, 1–2 additional SD could induce the loss of apical dominance, causing excessive elongation and leaf production in the subjacent branches. Further increase in the SD dose inhibited this elongation by accelerating the transformation of the apices of these branches to the reproductive state.Abbreviations LD long day(s) - SD short day(s) - ContSD continuous short day(s) - RGR relative growth rate     

Meiotic studies ofElymus nutans andE. jacquemontii (Poaceae,Triticeae) and their hybrids withPseudoroegneria spicata and seventeenElymus species

Hybridizations ofElymus nutans andE. jacquemontii were carried out with one species ofPseudoroegneria (S genome), and 20Elymus species, each containing either of the SH, SY, SYH, or SYW genomes. Chromosome configurations were analysed at metaphase I of the two target taxa and their interspecific hybrids. It is concluded that (i)E. nutans is an allohexaploid containing the SYH genomes, andE. jacquemontii is an allotetraploid having the SY genomes; (ii) the genomic affinity is associated with the geographic distance between the species studied; (iii) minor genomic structural rearrangements have occurred within the hexaploid taxon ofE. nutans.     

Primary structures of alpha- and beta-subunits of alpha-amylase inhibitors from seeds of three cultivars of Phaseolus beans

The primary structures of three -amylase inhibitors (TAI, DAI, and MAI-2) consisting of glycoprotein subunits and from the respective seeds of three cultivars of Phaseolus beans, Toramame (Phaseolus vulgaris L.), Daifukumame (Phaseolus vulgaris L.), and Murasakihanamame (Phaseolus coccineus L.) were determined by sequencing the peptide fragments derived from their enzymatic digestions. Major sugar chains of the inhibitors were also assessed by analyzing glycopeptides in the enzymatic digests. The subunits, and , were shown to be composed of 76 and 139 amino acid residues, respectively, in each inhibitor. The overall amino acid sequences of the inhibitors were slightly different from one another. Furthermore, the sequence of TAI was the same as that deduced from a cDNA clone encording -amylase inhibitor-1 from the common bean (Phaseolus vulgaris L.). It was also revealed that there were two N-glycosylation sites in each -subunit: PA-derivatives of the major N-glycans were estimated to be M6B at Asn(12) and M9A at Asn(65). Each -subunit of TAI and MAI-2 had two N-glycosylation sites, while the -subunit of DAI had only one site. The major N-glycans pyridylaminated were estimated to be M3X at Asn(63) in each -subunit and M3FX at Asn(83) in -subunits of TAI and MAI-2.     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

In vitro plant regeneration via somatic embryogenesis from root culture of some rhizomatous irises

A method for plant regeneration of Iris via somatic embryogenesis is described. Root and leaf pieces from in vitro-grown plants of several genotypes of rhizomatous Iris sp. were cultured in vitro. Callus induction occurred only on root cultures incubated under low light intensity (35 mol m^-2 s^-1) on two induction media containing 2,4-D (4.5 or 22.5 M), NAA (5.4 M) and kinetin (0.5 M). Somatic embryos developed after transfer of callus onto four regeneration media containing 9 or 22 M BA, or 5 M kinetin and 2 M TIBA or 9 M BA and 4 M TIBA. Plantlets could be obtained from these somatic embryos. Genotypic differences were found both in callus induction and somatic embryo formation, with I. pseudacorus responding better than I. versicolor or I. setosa. Cytological analysis performed on root tips of 80 regenerated plants revealed that two of the I. pseudacorus regenerants were tetraploid.Abbreviations 2,4-D dichlorophenoxy acetic acid - NAA naphthaleneacetic acid - BA 6-benzyladenine - TIBA 2,3,5-triiodobenzoic acid - IBA indolebutyric acid     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

Ultrastructure and behaviour of the spindle pole body of the aphid-pathogenic fungusErynia neoaphidis

Summary A detailed account of the ultrastructure and behaviour of the spindle pole body (SPB) of the entomophthoraceous fungusErynia neoaphidis is presented for the first time.The SPB consists of extranuclear (ENC) and intranuclear (INC) components. The ENC is a saucepan-shaped structure which lies in a pocket of the nuclear envelope. It is composed of a forked, fibrillar handle and a shallow, cylindrical pan. The pan has a wall of two layers, both of which are thickened with a regular periodicity so that they appear to be beaded. It is postulated that the pan is formed from rough endoplasmic reticulum and that it synthesizes the amorphous, electron-dense material coating the ENC.The INC is a saucer-shaped, electron-dense plaque in which the ends of the spindle microtubules terminate. During metaphase, a clear zone separates the INC from the nuclear envelope and persists until telophase. The roles of the amorphous, electron-dense material and the clear zone as well as the method of SPB replication are discussed.     

A new enzymatic route to the synthesis of 12-ketoursodeoxycholic acid

Summary Cholic acid (3,7,12-trihydroxy-5-cholanoic acid) was completely and selectively transformed into 12-ketoursodeoxycholic acid (3,7-dihydroxy-12-oxo-5-cholanoic acid) by means of two consecutive enzymatic steps catalyzed, the first, by 7- and 12-hydroxysteroid dehydrogenase and, the second, by 7-hydroxysteroid dehydrogenase. Coenzyme regeneration was carried out with -ketoglutarate-glutamate dehydrogenase and glucose-glucose dehydrogenase, respectively.     

ε-caprolactam,a new powerful inducer for the formation of Rhodococcus rhodochrous J1 nitrilase

We found that -caprolactam is a new powerful inducer for the formation of Rhodococcus rhodochrous J1 nitrilase. When Rhodococcus rhodochrous J1 cells were cultivated at 28°C for 120 h in a nutrient medium supplemented with 0.5% (w/v) -caprolactam, an enormous amount of nitrilase was formed in the cells which corresponded to approximately 30% of all soluble protein. The level of -caprolactam in the culture broth barely decreased in the course of cultivation. -Butyrolactam and -valerolactam also caused effective induction. The induction of nitrilase formation by -caprolactam was also observed in some other Rhodococcus strains.     

Somatic embryogenesis and plant regeneration in wild cotton (Gossypium klotzschianum)

A simple and efficient method for high frequency somatic embryogenesis and plant regeneration from hypocotyl-derived cultures and suspension cultures of Gossypium klotzschianum Anderss, a wild, diploid species of cotton is described here. Embryogenic cultures were induced from hypocotyl sections on MSB medium with 0.9 M 2,4-D and 2.32 M kinetin. MSB medium containing 0.045 M 2,4-D, 0.93 M kinetin, 2.46 M IBA promoted embryogenic culture proliferation and embryo development. Suspension cultures with 0.23 M 2,4-D and 0.93 M kinetin also produced many embryos. Somatic embryos cultured on MSB medium with PGRs produced secondary embryos, and embryos developed into normal plantlets on PGR-free MSB medium. Regenerated plantlets were transferred onto the quarter-strength MSB medium with 0.5% active charcoal to avoid recallusing. Hypocotyls were better than cotyledons for culture induction and plant regeneration. 2,4-D and kinetin were essential for culture induction and maintenance.     

Effect of genotype,explant and medium onin vitro regeneration of red pepper

In vitro plant regeneration was achieved inCapsicum praetermissum, C. baccatum andC. annuum cvs. G4, Bhiwapuri Sweet pepper, Cayenne pepper and Hybrid pepper. Shoots were induced from hypocotyl, cotyledon and leaf explants on Murashige and Skoog medium supplemented with 5.7 M indoleacetic acid (IAA)+13.3 M benzyladenine (BA); 22 M BA; and 44 M BA. Analysis of variance revealed that the most significant effect on shoot regeneration was due to the explant and it accounted for 56.3% of total variation observed. The genotype x explant effect on regeneration was minor relative to all other 2- and 3-way interactions because leaf explants consistently regenerated more shoots than hypocotyls or cotyledons in all the genotypes and thereby reduced the variation among the genotypes. Explant x medium interaction revealed that 22 M BA was the best growth regulator supplement in regeneration medium for optimal shoot regeneration from leaf explants. Rooting of regenerated shoots was achieved on 5.7 M IAA-containing medium, and the rooting response was better from shoots induced on medium fortified with 5.7 M IAA plus 13.3 M BA. Complete plantlets with diploid chromosome number (2n=2x=24) were transferred to soil and 60–70% of these plantlets survived and grew well.     

Photoperiodism and thermoperiodism in the predatory mite Amblyseius potentillae are probably based on the same mechanism

Summary A comparative study was made of the photoperiodic and thermoperiodic induction of diapause in the phytoseiid mite Amblyseius potentillae. Sensitivity to thermoperiod was found to be highest during the protonymphal and deutonymphal stages, with some sensitivity still being present in the young adult. Summation of both photoperiodic and thermoperiodic cycles was shown to take place, which demonstrated the presence of a photoperiodic counter as well as a thermoperiodic counter in these mites. Vitamin A appeared to be necessary for some early step in the physiological mechanism of diapause induction and not just for the expression of the diapause response. The light sensitivity threshold for photoperiodic induction of diapause was found to be extremely low, viz. less than 0.02 W/cm². Moreover, the light sensitivity threshold appeared to be strongly temperature dependent in A. potentillae. Experiments in which the mites experienced various sequences of short-day photoperiods and short-day thermoperiods, applied either concurrently or in succession, showed that the information collected by the photoperiodic counter and the thermoperiodic counter is integrated into one induction sum. These results strongly suggest that photoperiodic and thermoperiodic induction of diapause in these mites is based on the same physiological mechanism.Abbreviations DD continuous darkness - LL continuous light - LD light-dark cycle (e.g. LD 16:8 is a cycle of 16 h of light and 8 h of darkness) - TC thermoperiodic cycle (e.g. TC 16:8 (27°: 15°) is a thermoperiod with a 16 h thermophase of 27 °C and an 18 h cryophase of 15°C)     

Axillary shoot induction and plant regeneration in Plantago ovata Forssk

Axillary shoot induction and plant regeneration were obtained in Plantago ovata. The optimum medium for inducing axillary shoots was Murashige & Skoog (MS) medium [5] supplemented with 4.6 M kinetin and 0.05 M NAA. Rooting of shoots was best on half-strength MS medium containing 5.0 M IBA and 0.05 M kinetin. The regenerated plants were similar to the control plants in karyotypic and phenotypic details.     

Male reproductive effect of arsenic in mice

Arsenic, a known human carcinogen, was given to mice via drinking water as sodium arsenite at a dose 53.39, 133.47, 266.95 and 533.90 mol l for 35 days. A decrease in the activity of 17 HSD along with increase in LDH, GT activity were observed at 533.90 mol l. The observed sperm count, motility and morphological abnormalities in sperm were similar to control at lower dose levels. However at 533.90 mol l a significant decrease in sperm count and motility along with increase in abnormal sperm were noticed. Significant accumulation of arsenic in testes and accessory sex organs may be attributed to the arsenic binding to the tissues or greater cellular uptake. No effects were observed on indices studied for reproductive effects at 53.39 mol l arsenic close to which human being are exposed through drinking water under the present set of experimental conditions.     

N-andO-alkylation of glycoconjugates and polysaccharides by solid base in dimethyl sulphoxide/alkyl lodide

O-Methylation of simple neutral oligosaccharides is readily accomplished in dimethyl sulphoxide containing solid sodium hydroxide and methyl iodide [Cincanu I, Kerek F (1984) Carbohydr Res 131209-17]. This procedure has been extended to 2-acetamido-2-deoxy sugars and sialic acid-containing oligosaccharides. CompleteO-andN-methylation was in most cases achieved in 15 min. Esterification of carboxylic groups in uronic acids was fast and resulted in concomitant -elimination. The method is also suitable for methylation of glycoproteins and glycosphingolipids. Polysaccharides can also be methylated by this technique. Analysis of the products by gas-liquid chromatography and mass spectrometry showed no degradation products.Abbreviations lacto-N-tetraose LcOse₄, Gal3GlcNAc3Gal4Glc - lacto-N-fucopentaose III III³Fuc-nLcOse₄, Gal4[Fuc3]GlcNAc3Gal4Glc - trihexosylceramide GbOse₃Cer, Gal4Gal4Glc1-1Cer - globoside GbOse₄Cer, GalNAc3Gal4Glc1-1Cer - FAB-MS fas atom bombardment mass spectrometry     

Ultrastructure of lycopene containing chromoplasts in fruits ofAglaonema commutatum schott (Araceae)

Summary The ripening process in fruits ofA. commutatum is characterized by clearly distinguishable developmental stages of their pericarp plastids. With respect to predominant pigments and ultrastructural features the following scheme is proposed: 1. The green stage with a tendency to thylakoid degeneration and plastoglobule formation leads to 2. the yellow stage. An increasing number of globules, mostly being membrane associated, are converted to tubules. In this stage, the main pigments are -carotene and cryptoxanthine. The development of membraneous invaginations from the inner plastid envelope leads to 3. the red stage. Concomitantly with lycopene synthesis and incorporation, these envelope-derived membranes expand and become electron dense (after KMnO₄ treatment), but maintain their triple-layered structure. Chromoplasts of deep red coloured fruits (1,400 g lycopene g^–1 dry wt) contain lycopene crystals within the lumina of membraneous sacs which are also derived from the inner envelope membrane. The molar ratio between the three main pigments -carotene, cryptoxanthine, and lycopene is about 1110 in this final state. GA/OsO₄ fixation is unable to stabilize the lycopenic structures (membranes as well as crystals).     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

Copper but not iron limitation increases astaxanthin production by Phaffia rhodozyma in a chemically defined medium

The influence of copper (0–32 M) and iron (0–108 M) on growth and astaxanthin production by Phaffia rhodozyma was studied. Copper below 3.2 M increased the astaxanthin content of the cells (from 220 to 287 g g^–1) but at the expense of a slightly decreased growth (from 11.3 to 10.2 mg ml^–1). In contrast, iron below 1 M decreased both the growth and astaxanthin content of the cells. Using copper limitation instead of toxic respiratory inhibitors to improve astaxanthin production has obvious advantages from the product quality, environmental and process operation points of view.     

Cryptomonad biliproteins — an evolutionary perspective

Each cryptomonad strain contains only a single spectroscopic type of biliprotein. These biliproteins are isolated as 50000 kDa '₂ complexes which carry one bilin on the and three on the subunit. Six different bilins are present on the cryptomonad biliproteins, two of which (phycocyanobilin and phycoerythrobilin) also occur in cyanobacterial and rhodophytan biliproteins, while four are known only in the cryptomonads. The subunit is encoded on the chloroplast genome, whereas the subunits are encoded by a small nuclear multigene family. The subunits of all cryptomonad biliproteins, regardless of spectroscopic type, have highly conserved amino acid sequences, which show > 80% identity with those of rhodophytan phycoerythrin subunits. In contrast, cyanobacteria and red algal chloroplasts each contain several spectroscopically distinct biliproteins organized into macromolecular complexes (phycobilisomes). The data on biliproteins, as well as several other lines of evidence, indicate that the cryptomonad biliprotein antenna system is primitive and antedates that of the cyanobacteria. It is proposed that the gene encoding the cryptomonad biliprotein subunit is the ancestral gene of the gene family encoding cyanobacterial and rhodophytan biliprotein and subunits.Abbreviations Chl chlorophyll - CER chloroplast endoplasmic reticulum - SSU rRNA small subunit ribosomal RNA     

DNA variations in regenerated plants of pea (Pisum sativum L.)

Summary The aim of this study was to determine whether DNA variations could be detected in regenerated pea plants. Two different genotypes were analyzed by cytogenetic and molecular techniques: the Dolce Provenza cultivar and the 5075 experimental line. Dolce Provenza regenerated plants showed a reduction in DNA content, particularly at the level of unique sequences and ribosomal genes. Moreover, regeneration was associated with an increase in DNA methylation of both internal and external cytosines of the CCG sequence. On the other hand, the DNA content of the 5075 line remained stable after regeneration. DNA reduction was found only in 5075 plants regenerated from callus cultures maintained for long incubation periods (about a year). The DNA variations observed are discussed both in relation to the genotype source and the role of tissue-culture stress.