The spermatozoon of Oikopleura dioica Fol (Larvacea,Tunicata)

Summary The spermatozoon of Oikopleura dioica is about 30 m long, with a spherical head, about 1 m wide, a 3 m long and 1 m wide midpiece, and a 25 m long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 m³. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.     

Clonal propagation of Callistemon by tissue culture techniques

Callus development in Callistemon viminalis was readily achieved when axillary buds derived from nodal tissue were placed in a medium containing macro- and micro-nutrients, sucrose (0.06 M), inositol (300 M), nicotinic acid (20 M), pyridoxine hydrochloride (3 M), thiamine hydrochloride (2 M), riboflavin (10 M), cytokinins (5 M) and auxins (0.1 M). The presence of benzylaminopurine (5 M) and p-chlorophenoxyacetic acid (0.1 M) promoted the most vigorous callus development and sprout formation. Rooting of nodal material was rare but occurred readily following the transference of sprouts developed on callus to a basal medium containing sucrose and salts. Root initiation was stimulated, however, by the presence of auxins. Chlorophenoxyacetic acid while stimulating root initiation repressed root growth. Indole butyric acid stimulated both root initiation and shoot growth at concentrations of 0.005 to 0.1 M. The treatment of choice for rooting and shoot growth was the addition of indole butyric acid at a concentration of 0.01 M.     

Saccharomyces cerevisiae 2-mum DNA. An analysis of the monomer and its multimers by electron microscopy.

Summary The non-tandem inverted duplication in the 2-m DNA of Saccharomyces cerevisiae has a length of 0.19 m and is located asymmetrically along the molecule. The majority of the dumb-bell structures that are formed upon denaturation and selfannealing of the 2-m monomer consists of the renatured inverted duplication sequences as double stranded stem and two single stranded loops of 0.67 m±0.06 m (S-loop) and 0.86 m±0.05 m (L-loop) length. Two additional size classes which comprised 5–10% of the measured molecules had contour lengths of around 1.7 m and 2.1 m. The smaller dumb-bells contained two S-loops and the larger dumb-bells contained two L-loops as was shown by heteroduplex mapping with an HindIII fragment from the L-loop. Two models which assume illegitimate or site specific recombination, are presented to explain the generation of double S-loop and double L-loop molecules. At least part of the 4-m and 6- circular molecules present in the yeast supercoiled DNA fraction are shown to be dimers and trimers of 2-m monomers, but often with inverted loop segments most probably due to intramolecular recombination between sequences of the inverted duplication.2-m DNA is used to indicate the supercoiled DNA fraction although in our measurements the average monomeric length is 1.9 mPart of this work has been presented at the Conference: The Genetics and Biogenesis of Chloroplasts and Mitochondria, Munich, August, 1976     

Method of isolation of cysteine constitutive mutants of the cysteine regulon in Salmonella typhimurium.

Summary Size and shape of mitochondrial DNA molecules of Schizosaccharomyces pombe were analyzed by electron microscopy. Besides numerous linear molecules, circular molecules ranging from 0.83 m to 12.81 m were found. Depending on the method of preparation, both closed and open circular molecules were found. Most of the circular molecules could be assigned to five major size classes of 0.83±0.05 m, 1.7±0.05 m, 4.74±0.04 m, 5.74±0.04 m, and 8.32±0.07 m. Possible explanations for the different size classes of mitochondrial DNA molecules are discussed.     

Oocysts of Isospora ernsti n. sp. and Isospora blagburni n. sp. (Apicomplexa: Eimeriidae) from the black-capped bulbul,Pycnonotus xanthopygos

Oocysts of Isospora ernsti n. sp. and Isospora blagburni n. sp. are described from the black-capped bulbul Pycnonotus xanthopygos from Lincoln Park Zoo, Chicago, Illinois. The bird came from southwestern Africa seven years earlier. I. ernsti oocysts are ellipsoidal to bluntly ovoid, 28–38 × 23–31m (mean 34 × 28 m) and have a single-layered oocyst wall. Micropyle, oocyst residuum and polar granules are absent. Sporocysts are elongate ovoid, 24–30 × 11–16 m (mean 27×13 m). Stieda and substiedal bodies and sporocyst residuum are present. I. blagburni oocysts are spherical to subspherical. 21–28 × 19–26 m (mean 25 × 23 m) and have a single oocyst wall. Sporocysts are ovoid and 17–23 × 10–13 m (mean 20 × 12 m). Stieda and substiedal bodies and sporocyst residuum are present.     

Plant regeneration through direct shoot bud formation from leaf cultures of Paphiopedilum orchids

Leaf explants of Paphiopedilum phiIippinense hybrids (hybrid PH59 and PH60) directly formed adventitious shoots from wound regions within 1 month, when cultured on modified Murashige and Skoog medium (1/2-strength macro- and full-strength micro-elements) free of plant growth regulator in darkness. The combinations of 2,4-dichlorophenoxyacetic acid ((2,4-D) acid (0, 4.52 and 45.25 M) and 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ) (0, 0.45, 4.54 and 22.71 M) were used to test their effects on direct shoot bud formation from two types of explants (1.5-cm long intact leaf explants and 0.5-cm long leaf segment explants). In hybrid PH59, 4.54 M TDZ increased mean numbers of shoots per explant with leaf segment explants. In hybrid PH60, 4.52 M 2,4-D plus 0.45 M TDZ promoted direct shoot bud formation from leaf segment explants. In addition, three treatments (4.52 M 2,4-D, 22.71 M TDZ, 4.52 M 2,4-D plus 4.54 M TDZ) gave a higher response than control on mean numbers of shoots per explant with intact leaf explants. Healthy plantlets each with one to three roots were obtained from leaf-derived shoots after transfer onto a hormone-free medium for 22 months. These plantlets were acclimatized in a greenhouse and grew well with 100% survival rate.     

Resistance to Spodoptera exigua in Apium prostratum

Two Apium accessions were compared with the commercial cultivar Tall Utah 52–70R (A. graveolens [L.]) for resistance to Spodoptera exigua (Hübner)(Lepidoptera: Noctuidae). Oviposition rate was not significantly different between the three genotypes. In all accessions, eggs were usually placed on the upper half of the plants. Implications of this oviposition pattern on S. exigua management in celery are discussed. The wild species A. prostratum ssp prostratum var filiform (A230) showed a significantly higher resistance to S. exigua than 52–70R. The levels of carcinogenic and mutagenic linear furanocoumarins in the commercial cultivar 52–70R (1.41 g/g in the petioles; 5.85 g/g in the leaves) and in the plant accession A. nodiflorum (5.40 g/g in the petioles; 2.99 g/g in the leaves) were far below the concentration reported to produce acute contact dermatitis (18.0 g/g). The levels of furanocoumarins in A. prostratum petioles (186.14 g/g) and leaves (326.45 g/g) were 10 and 18 times higher, respectively, than the concentration known to cause contact dermatitis. However, resistance in A. prostratum was primarily due to non-preference and the linear furanocoumarins did not induce non-preference. Therefore, the resistance shown by this plant accession does not appear to be furanocoumarin-based and may be suitable for transfer to commercial celery for use in S. exigua management.     

Effects of lead and cadmium on chemical composition and total water content of the pupal parasitoid, Pimpla turionellae

The parasitoid Pimpla turionellae L. (Hymenoptera, Ichneumonidae) was fed on Cd, Pb and Cd+Pb-contaminated food (33g Cd, 82g Pb and 33g Cd+82g Pb per gram food fresh weight, respectively). Significant decrease in the total lipid and protein content was found along with an increase in the water content particularly in Cd-contaminated parasitoids.     

Trois nouveaux Nadejdolepis Spasskii & Sasskaya, 1954 (Cestoda: Hymenolepididae) parasites de Charadrii (Aves) de Tasmanie

Three species of Nadejdolepis from Tasmania, Australia, are described and illustrated. N. burgessi n. sp., a parasite of Charadrius ruficapillus, is 4-6 mm long, with rostellar nitiduloid hooks 63-66 m long, a short evaginated cirrus 13-16 m long with a short collar of thin spines 1 m long, a narrow and tubular sclerotinoid vagina 40-50 long and 3-4 m in diameter with a little ampulla 3-5 m in diameter at the proximal end, and a membranous atrial segment with smooth, short (1 m) and compact spines which are sometimes difficult to observe. N. smithi n. sp., a parasite of 40-50 long and 3-4 m in diameter with a little ampulla 3-5 m in diameter at the proximal end, and a membranous atrial segment with smooth, short (1 m) and compact spines which are     

Norway spruce somatic embryogenesis: high-frequency initiation from light-cultured mature embryos

Somatic embryos and rooted plantlets have been regenerated from light-initiated embryogenic callus derived from mature embryos of Picea abies. Under a 16 h photoperiod, mature zygotic embryos were cultured on a modified half-strength Murashige & Skoog medium without NH₄NO₃ and supplemented with 5 mM glutamine, 4.5 M N6-benzyladenine and 10.7 M naphthaleneacetic acid or 10 M 2,4-dichlorophenoxyacetic acid. White translucent embryogenic callus, proliferating from the callusing hypocotyl region after 3 weeks incubation, was isolated from the green non-embryogenic tissue and subcultured for over 12 months. Upon transfer of the embryogenic callus through a specific sequence of media, somatic embryos proceeded to mature, elongating and forming rings of cotyledonary leaves similar to those of zygotic embryos. Transferred to medium without growth regulators, the somatic embryos germinated and produced plantlets with green cotyledons, elongated hypocotyls and primary roots.     

Ultrastructural analysis ofSpinacia oleracea sperm cells isolated from mature pollen grains

Summary In isolated condition, the sperm cells ofSpinacia oleracea are no longer arranged in pairs as in the pollen grain. The vegetative membrane, which surrounds a sperm cell pair in a mature pollen grain, is lost during the isolation procedure. The sperm cells become spherical in shape.The isolated sperm cell is surrounded by an intact plasma membrane. The heterochromatic or euchromatic sperm cell nucleus is located in the cell center. Mitochondria are round to oval and have distinct cristae. Often they are clustered in groups of 5 to 10 mitochondria. Dictyosomes are present in the cytoplasm and consist of 4 to 5 cisterns. Endoplasmatic reticulum is mostly situated at the sperm cell periphery, as single cisterns very near the plasma membrane.From diameters of sectioned sperm cells in electron micrographs, it is possible to calculate the average diameter of the whole sperm cell. This average diameter is 3.66 m with a variation of 3.0 m to 4.2 m, resulting in an average volume of 25.6 m³. The nuclear volume is 12.8 m³ (50.0% of the whole cell) and the mitochondrial volume is 0.7 m³ (2.5% of the whole cell). The frequency distribution of the isolated sperm cells diameters shows only one peak with a normal distribution, indicating that there is no dimorphism in volume.     

Micropropagation and ecorestoration of Vanda spathulata,an exquisite orchid

Node explants collected from flowering plants of Vanda spathulata, an endemic and exquisite orchid of Peninsular India and Sri Lanka, were cultured in Mitra medium with combinations of 4.4–88.8 m 6-benzyl adenine (BA) and 0.0–114.2 m indole-3-acetic acid (IAA). Combinations of 44.4 m BA with 17.1 or 28.5 m IAA and 66.6 mM BA with 28.5 or 40.0 m IAA induced maximum formation of 12.6 and 12.1 shoots / node, respectively, in a 6-month period. Subcultured nodal explants produced maximum of 6.1 shoots at combinations of 22.2–44.4 m 21 BA and 5.7–28.5 m IAA. Rooting of shoots occurred in medium containing 75 g l^–1 banana pulp and 5.7 m IAA within 3–9 weeks. Plantlets of 2–5 cm length possessing two to five roots established easily in community pots at 80–90% rates without hardening. Community potted plants introduced into forest segments at Ponmudi and Palode in Southern Western Ghats of India established at a rate of 50–70%.     

Genes of the constant regions of functional immunoglobulin heavy chain of Japanese flounder,<Emphasis Type="Italic"> Paralichthys olivaceus</Emphasis>

IgM and IgD genes of the Japanese flounder were cloned and characterized from a genomic bacterial artificial chromosome (BAC) library. The gene contained four constant region exons (C1–C4), and two transmembrane exons (TM1 and TM2), which conforms to the organizational pattern of all other vertebrate -chain genes examined so far. In the same BAC clone, the gene, which is homologous to the IgD gene in mammals and teleost fish, was found immediately (0.9 kb) downstream of the IgM gene. This gene encoded seven exons (C1–C7) and two TM exons (TM1 and TM2) and had no duplication of C1-C2, as found in Atlantic cod, or C2-C3-C4, as found in Atlantic salmon and channel catfish. Phylogenetic and sequence analyses strongly suggest that teleost is more closely related to non-IgM isotypes than IgM isotypes. The heavy chain (IgH) locus of Japanese flounder, which encodes m, s and m, was found to be fully functional.     

The effect of monoterpenes on astaxanthin production by a mutant ofPhaffia rhodozyma

Summary The total pigment and astaxanthin content ofPhaffia rhodozyma increased with increasing concentrations -pinene up to 500 l -pinene/l. Above this concentration the total pigment and astaxanthin content as well as the biomass production decreased. The addition of 500 l -pinene/l increased the total pigment content from 1652 g/g to 2201 g/g and the astaxanthin content from 1554 g/g to 1883 g/g. A sharp decrease in maximum specific growth rate occurred above 150 l -pinene/l.     

Intestinal microflora in the deep-sea isopodBathynomus giganteus

Observations with the scanning electron microscope showed that the deep-sea isopodBathynomus giganteus harbors a dense microflora within the digestive tract. The gut microflora is composed of a diversity of microorganisms, including an unusually large bacterial morphotype that predominates almost exclusively in the anterior end of the hindgut. The majority of these large bacteria measured 1.9 m×8.5 m and many reached a size of 2.0 m×10.0 m.     

Optimization of an electroporation procedure for Kluyveromyces lactis transformation

Summary An electroporation method using a Bio-Rad Gene Pulser has been optimized for introducing heterologous DNA into Kluyveromyces lactis yeasts. The plasmid pCR1, derived from a native Kluyveromyces plasmid, was used to transform K. lactis. This plasmid produces a wheat -amylase and contains both the biosynthetic marker URAA and G418 resistance genes. Transformation was optimal at 4500 V/cm, 25 F, and with 0.2 g plasmid DNA. Transformation efficiencies in the range 10⁴–10⁵ transformants/10⁷ cells/g DNA were obtained.     

Establishment and characterization of Rubus tissue culture systems for in vitro bioassays against phytotoxins from Rubus fungal pathogens

The Rubus species R. parviflorus, R. spectabilis and R. strigosus interfere with conifer seedling establishment on forest regeneration sites in Canada and the United States. As a first step towards microbial metabolite-based control, callus and cell suspension cultures of the Rubus species were developed as a bioassay system to detect phytotoxic compounds that may have relevance in a vegetation control context. Rapidly growing friable callus and suspension cultures were obtained from leaf disks of the three weedy Rubus species using similar culture media conditions (modified Murashige and Skoog) but required different plant growth regulators (R. parviflorus, 4.5 M 2,4-D; R. spectabilis, 26.9 M NAA/0.5 M zeatin; and R. strigosus, 12.4 M picloram). Cell growth and health attributes including callus circumference, degree of browning and suspension culture cell viability as measured by the TTC vital stain assay were developed and were rapid and convenient to use. We have established Rubus tissue culture systems that will make it possible for large scale screening of phytotoxic metabolites.     

Ultrastructure of Sporothrix schenckii treated with iodine-potassium iodide solution

The ultrastructural changes produced by iodine-potassium iodide solution on yeast cells of Sporothrix schenckii were investigated by transmission electron microscopy in order to clarify the mechanism of oral potassium iodide therapy for sporotrichosis. Yeast cells were dipped with solutions containing various concentrations of iodine. The rate of germination decreased markedly between the range of iodine concentrations from 0.63 g/ml to 5.0 g/ml. No significant ultrastructural changes were seen at the concentration of the iodine of 1.25 g/ml (80% germination) or less. In the concentration of 2.5 g/ml (50% germination), normal cells and degenerated cells coexisted. When the cells were treated with 5.0 g of iodine per ml (0% germination) or more, their interior structures were completely destroyed. It is assumed that iodine treatment of the organism causes rapid destruction in the whole cell.     

Somatic embryogenesis in Simarouba glauca

Frequency of somatic embryogenesis from callus cultures derived from immature cotyledon explants of Simarouba glauca Linn. was highest on solid MS medium supplemented with 11.1 M benzyladenine and 13.42 M -naphthaleneacetic acid. On transfer of the somatic embryos into maturation medium containing half-strength MS medium supplemented with 1.89 M abscisic acid (ABA) and 2% (w/v)sucrose, 20–25 % of embryos germinated within 20 days of culture with distinct cotyledon, hypocotyl and radicle.     

The initiation of callus culture ofMichelia champaca for essential oil production

Summary TheMichelia champaca callus was induced from rachises of theM. champaca flowers on 1/2 MS medium containing 3% sugar and 0.9% agar. The medium was also supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) and 6-benzylaminopurine (BAP) as the growth regulators. It was observed that the calli ofM. champaca could be induced on media containing 0–50 M 2,4-D and 0.1–1 M BAP. The calli were grown well on media on media containing 0.1–1.0 M BAP and 2,4-D up to 50 M. As 1 M BAP was used, a lower concentration of 2,4-D was associated with a fast initiation of calli, but the culture of these calli turned brown quickly. To the contrary, a higher concentration of 2,4-D led to a slower rate of callus formation and the culture hardly turned brown. The optimum pH for the cell culture was about 5.6 as 1 M of 2,4-D and BAP were present in the medium.