Coccidia of Brazilian edentates: Eimeria cyclopei n.sp. from the silky anteater,Cyclopes didactylus (Linn.) and Eimeria choloepi n.sp. from the two-toed sloth,Choloepus didactylus (Linn.)

Summary Eimeria cyclopei n.sp. is described from the silky anteater, Cyclopes didactylus, from Pará State, north Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in seven days at 26 to 28°C. Oocysts are ellipsoidal to sub-spherical, with a mean size of 28.1 × 23.6 m: the wall is 1.5 to 2.0 m thick, apparently with an outer thin, colourless membrane and two inner, thicker, striated and yellowish layers. There is no micropyle, oocyst residuum or polar body. The mean measurements of sporocysts are 19.0 × 9.0 m, and they are slightly asymmetrical, elongate pear-shape, with a plug-shaped Steida body projecting beyond the end of the sporocyst. Sporozoites are as long as or longer than the sporocysts: The sporocyst residuum is scattered between sporozoites in younger specimens and becomes condensed into rounded mass in older ones. The endogenous stages occur in the epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Uninucleate meront, microgamont and macrogamont precursors are recognizable morphologically. Mature meronts are 20.0 × 15.7 m some produce 12 to 20 merozoites which are 8.7 × 2.0 m, and others 10 to 26 merozoites which are 11.4 × 2.0 to 15.0 × 3.0 m. Mature microgamonts which are 27.5 × 24.1 m, produce from 150 to 170 microgametes of 7.1 × 1.0 m: microgametes have two flagella of unequal length. Mature macrogamonts are 28.4 × 24.5 m Eimeria choloepi n.sp. is recorded from the two-toed sloth, Choloepus didactylus, from the same area of Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in 23 days at 26 to 28°C. Oocysts with a mean size of 23.0 × 20.3 m, have a wall 2.0 to 2.5 m thick which is composed of two thick, yellowish and striated outer layers and a delicate, colourless inner one. There is no micropyle, oocyst residuum or polar granule. Mature sporocysts with a mean size of 11.3 × 7.1 m, are ellipsoidal to egg-shaped and have a poorly developed Steida body. The sporocyst residuum is composed of a small number of large globules: The sporozoites are longer than the sporocyst and strongly recurved. The endogenous stages occur in epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Dimorphic meronts produce 8 to 18 merozoites which are either 13.0 × 2.0 m or 13.0 × 3.0 m. Microgamonts produce 50 to 80 microgametes of 8.0 × 1.0 m. Mature macrogamonts are 18.3 × 17.9 m. ac]19820212     

Effects of background adaptation on α-MSH and β-endorphin in secretory granule types of melanotrope cells of Xenopus laevis

Placing the clawed toad Xenopus laevis on a black background stimulates the melanotrope cells in the pars intermedia of the pituitary gland to release proopiomelanocortin (POMC)-derived peptides, including -MSH and N-acetyl-endorphin. In this study three types of secretory granules, electron-dense(130 nm Ø), moderately electron-dense ( 160 nm Ø) and electronlucent ( 180 nm Ø), have been identified in these cells. Apparently, only dark granules are formed by the Golgi apparatus and lucent granules release their contents via exocytosis. Immuno-electron microscopy (immunogold double labelling) of glutaraldehyde-fixed and freeze-substituted material shows that desacetyl--MSH and N-acetyl--endorphin coexist in all three granule types. Quantification of immunostaining revealed that immunoreactivities to these peptides are lowest in the dark granules and highest in the light ones. It is proposed that intragranular processing of POMC to immunoreactive desacetyl--MSH and N-acetyl--endorphin involves an increase in granule size and a decrease in granule electron density. Black background-induced activation of the melanotrope cell is reflected by an increase in immunoreactivity of the secretory granules to each of the antisera. This suggests that cell activation stimulates the formation of peptides by intragranular processing of POMC and/or of intermediate POMC-processing products. In addition, cell activation evoked an increase in the percentage of the granule population that reacts with anti-N-acetyl--endorphin, probably by stimulating intragranular acetylation of -endorphin. Apparently, this acetylation is a regulated event that occurs in the cytoplasm, independently from the acetylation of desacetyl--MSH which takes place near the plasmalemma at the time of granule exocytosis.     

Peptide des β-Alanins als Ersatz für die freie Aminosäure bei pantothensäurebedürftigen Hefezellen und ihr Verhalten gegenüber dem β-Alanin-Antagonisten Asparagin

Zusammenfassung Pantothensäurebedürftige Hefezellen können ihren Bedarf an diesem Vitamin nicht allein aus -Alanin decken, sondern auch aus Benzoyl--Alanin, -Alanyl-d,l-Norleucin und -Alanyl-l-Histidin. Der Antagonist Asparagin hemmt die Verwertung dieser Peptide genauso wie diejenige der freien Aminosäure. Durch höhere Konzentrationen an -Alanin oder -Alanyl-d,l-Norleucin läßt sich die Hemmwirkung nicht allein kompensieren, es kommt sogar zu einer Förderung des Hefewachstums. Der Antagonist wird dann zum Synergisten.

---

Summary The -alanine containing peptides benzoyl--alanine, -alanyl-d,l-norleucine and -alanyl-l-histidine can substitute for the amino acid -alanine in a pantothenic acid requiring yeast. Asparagine, an antagonist of -alanine, affects these peptides in a similar manner. In combination with an overdose of -alanine or -alanyl-d,l-norleucine, asparagine is no longer an antagonist but becomes a synergist.

     

Efficient plant regeneration protocol through callus for Saussurea obvallata (DC.) Edgew. (Asteraceae): effect of explant type, age and plant growth regulators

A callus induction and in vitro plantlet regeneration system for the endangered state flower of Uttaranchal (Saussurea obvallata) was optimized by studying the influence of explant type (root, hypocotyl, cotyledon and leaf), age and different concentrations of plant growth regulators. Explants from 10 to 15-day-old seedlings showed maximum callus induction. Callus formation and shoot differentiation was initiated on Murashige-Skoog (MS) medium containing 6-benzyladenine (BA) and -naphthalene acetic acid (NAA) in all explant types. The best results were obtained using leaf explants: 100% callusing was achieved in MS medium supplemented with 2.5 M BA and 1.0 M NAA, and 100% differentiation along with a multiplication rate of 12 shoots per explant with a combination of 5.0 M BA and 1.0 M NAA. However, the results reflected the existence of high inter-explant variability in response to growth regulators. In vitro rooting of shoots was achieved at an efficiency of 100% in one-half strength MS medium supplemented with 2.5 M indole-3-butyric acid. Application of this protocol has potential for mass multiplication of the target species in a limited time period.     

The structure of cyanobacterial phycobilisomes: a model

Phycobilisomes, supramolecular complexes of water-soluble accessory pigments, serve as the major light-harvesting antennae in cyanobacteria and red algae. Regular arrays of these organelles are found on the surface of the thylakoid membranes of these organisms. In the present study, the hemi-discoidal phycobilisomes of several species of cyanobacteria were examined in thin sections of cells and by negative staining after isolation and fixation. Their fundamental structures were found to be the same. Isolated phycobilisomes possessed a triangular core assembled from three stacks of disc-shaped subunits. Each stack contained two discs which were 12 nm in diameter and 6–7 nm thick. Each of these discs was probably subdivided into halves 3–3.5 nm thick. Radiating from each of two sides of the triangular core were three rods 12 nm in diameter. Each rod consisted of stacks of 2 to 6 disc-shaped subunits 6 nm thick. These discs were subdivided into halves 3 nm thick.The average number of discs of 6 nm thickness forming the peripheral rods varied among the strains studied. For certain chromatically adapting strains, the average rod length was dependent upon the wavelength of light to which cells were exposed during growth. Analyses of phycobilisomes by spectroscopic techniques, polyacrylamide gel electrophoresis, and electron microscopy were compared. These analyses suggested that the triangular core was composed of allophycocyanin and that the peripheral rods contained phycocyanin and phycoerythrin (when present). A detailed model of the hemi-discoidal phycobilisome is proposed. This model can account for many aspects of phycobiliprotein assembly and energy transfer.Abbreviations PBS phycobilisome(s) - PBP phycobiliprotein(s) - AP allophycocyanin - PC phycocyanin - PE phycoerythrin - PEC phycoerythrocyanin - AP-B allophycocyanin B - C- cyanobacterial - R- rhodophytan - B- Bangiophycean - SDS sodium dodecyl sulfate - LPP Lyngbya-Plectonema-Phormidium group - Na-KPO₄ buffers NaH₂PO₄ titrated with a solution of KH₂PO₄ of equivalent molarity to a given pH     

Capnocytophaga: New genus of Gram-negative gliding bacteria. II. Morphology and ultrastructure

Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 m×0.38–0.5 m and large 4.8–5.8 m×0.42–0.6 m cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.     

Hexagonally ordered “rosettes” of particles in the plasma membrane ofMicrasterias denticulata Bréb. and their significance for microfibril formation and orientation

Summary Cells ofMicrasterias denticulata Bréb. at the stage of secondary wall formation have been studied by freeze-etching. It was found that the plasma membrane exhibits oval areas in which arrays of membrane particles occur. These particles form rosettes which are arranged in a hexagonally ordered lattice with a center to center spacing of 25 nm. Nearly the same periodicities can be found between microfibrils. It is concluded that the rosettes probably together with the thickened area of the plasma membrane below them represent the apparatus for the production and orientation of microfibrils. The hypothesis suggesting the incorporation of membrane templates functional in microfibril formation, originally advanced byKiermayer andDobberstein (1973) has received further support.     

Methylobacterium rhodesianum MB 126 possesses two acetoacetyl-CoA reductases

Two constitutive acetoacetyl-CoA (AcAc-CoA) reductases were purified from Methylobacterium rhodesianum MB 126, an NADPH-linked d(-)--hydroxybutyryl-CoA forming reductase (enzyme A) and an NADH-and NADPH-linked l(+)--hydroxybutyryl-CoA forming reductase (enzyme B). Enzyme A and B give apparent K _m values of 15 M and 30 M for AcAc-CoA, 18 M for NADPH and 30 M for NADH, respectively. They are inhibited by AcAc-CoA at concentrations higher than 25 M and 50 M, respectively. The contribution of the two reductases to poly--hydroxybutyrate synthesis is discussed.     

Myosatellite cells associated with different muscle fibre types in the Atlantic hagfish (Myxine glutinosa,L.)

Summary The incidence of myosatellite cells associated with white and red muscle fibres of the parietal muscle and red fibres of the craniovelar muscle was estimated by quantitative electron microscopy in the Atlantic hagfish (Myxine glutinosa, L.). Myosatellite cell nuclei constitute 3, 11 and 23 % of the total number of nuclei inside the basal lamina of the three types of muscle fibres, respectively. However, the total number of nuclei is highest in white fibres, most of the nuclei belonging to striated muscle cells. Myosatellite cell profiles in transverse sections constitute 23, 41 and 61 % of the number of muscle fibre profiles of the three types, respectively. The intervals between adjacent myosatellite cells are 135 m in white fibres, 55 m in red parietal fibres, and only 25 m in craniovelar fibres. Since craniovelar fibres are also comparatively thin, myosatellite cells constitute a significant fraction of the volume inside the basal lamina in these fibres. The myosatellite cells are 30–50 m long and up to 5 m thick. Some myosatellite cells possess few organelles, whereas others appear to contain many free ribosomes, granular endoplasmic reticulum, prominent Golgi apparatus and lysosome-like bodies.This investigation was supported by the Norwegian Research Council for Science and the Humanities (NAVF grant No. C20.30–37). The authors are indebted to Jorunn Line Vaaland and Berit Branil for technical assistance, and to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supplying the hagfish     

The carotenoids of Flavobacterium strain R1560

The main carotenoid of Flavobacterium strain R1560 has been identified as (3R,3R)-zeaxanthin. Also present were small amounts of 15-cis-phytoene, phytofluene, -carotene (7,8,7,8-tetrahydro-, -carotene plus 7,8,11,12-tetrahydro-, -carotene), neurosporene, lycopene, -zeacarotene, -carotene, -carotene, -cryptoxanthin, rubixanthin, 3-hydroxy--zeacarotene and several apo-carotenals. Zeaxanthin production was inhibited by nicotine (10 mM), and lycopene and rubixanthin accumulated. The biosynthesis of zeaxanthin is discussed in terms of pathways and also of half-molecule reaction sequences. The presence of zeaxanthin may be a characteristic of a group of Flavobacterium species, and may thus be useful in the taxonomic classification of these organisms.     

Analysis of the methylated ‘cap’ structures of vaccinia mRNA by two-dimensional thin-layer chromatography

Two different twodimensional cellulose thinlayer separations for blocked, methylated mRNA 5-termini are described. They allow rapid analysis even of complex mixtures of mRNA cap structures on the basis of their methyl group content and base composition. These simple procedures are especially useful for the analysis of [³H-methyl]-labeled mRNA in combination with tritium fluorography. A qualitative and quantitative analysis of the methylated cap structures of in vitro labeled Vaccinia core mRNA is presented. The presence of methylated cap structures in Vaccinia RNA increases the in vitro translation efficiency of methylated Vaccinia RNA over Vaccinia RNA transcribed in the absence of a methyl group donor.     

Synthesis of nanophase hydroxyapatite by a <Emphasis Type="Italic">Serratia</Emphasis> sp. from waste-water containing inorganic phosphate

Synthesis of nanophase hydroxyapatite (HA) on a bacterial surface was achieved at the expense of CaCl₂ and inorganic phosphate (Pi). After initial nucleation, calcium was precipitated on and around the cells as calcium phosphate at the expense of inorganic phosphate in the challenge solution, with no precipitation in cell-free controls. HA was also biomanufactured using inorganic phosphate ions scavenged from a phosphate-containing waste-water. With additional Ca²⁺, the concentration of phosphate was decreased from 0.27 (25ppm) to 0.02m (2ppm) in the waste-water. Crystals of calcium phosphate manufactured by the cells were located by scanning electron microscopy (SEM) and identified as HA by X-ray powder diffraction, with an average crystal size calculated as 25nm. Possible application of bioHA as a biomaterial and implications for one-step `waste-into product' are discussed.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Antlers as biomonitors of environmental pollution by lead and fluoride: A review

Antlers are periodically cast and re-grown cranial appendages of deer. Both endochondral and intramembranous ossification are involved in the formation of antler bone. After velvet shedding, antlers are completely bony structures which are referred to as hard antlers. Growing antlers accumulate substances with an affinity to mineralized tissues. Among these substances are lead and fluoride. Due to the seasonally limited life span of antlers, the concentrations of lead and fluoride in hard antlers reflect uptake by the forming bone during a defined, species-specific period of some months. Antlers can thus be viewed as naturally standardized environmental samples that are well suited as biomonitors of environmental pollution by bone-seeking contaminants. Because hard antlers are collected by hunters as trophies and kept in private or public collections, material for study can be obtained rather easily. So far, lead concentrations in hard antlers have been reported only from Europe, whereas data for fluoride are available from both Europe and North America. Some studies compared contaminant concentrations in antlers from different regions, while others analyzed time-trends in contaminant levels in antlers from a single region. Using the latter approach, a pronounced drop of lead concentrations during recent decades has been reported for antlers from various European countries. This indicates a marked decline of environmental lead levels that can be attributed mainly to the phase-out of leaded gasoline and, in addition, to a reduction of lead emissions also from stationary sources. In Germany, a corresponding drop has also been recorded for fluoride concentrations in antlers, which is attributed to a decline of fluoride emissions from stationary sources due to improved emission-control measures. There is some evidence that exposure to higher levels of fluoride may lead to an impaired antler mineralization. Using antlers as biomonitors has been shown to be an efficient method for assessing environmental pollution by lead and fluoride at low cost. Further studies using this now well established approach are therefore encouraged.This revised version was published online in May 2005. The following errors were eliminated:1. In the chapter Antler growth and mineralization in the last sentence of the first paragraph a slash was missing between the words reindeer and caribou; 2. In the second paragraph of the same chapter the word reiudees was corrected to reindeer; 3. In the chapter Accumulation of lead and fluoride in growing antlers the word lightest was corrected to highest.     

Effects of hypoxia and intracellular iron chelation on hypoxia-inducible factor-1α and -1β in the rat carotid body and glomus cells

The present investigation provides for the first time, unambiguous information on the occurrence of hypoxia-inducible factors (HIF-1 and HIF-1 proteins) in normoxia (Nx) and their interaction with hypoxia (Hx) and intracellular Fe²⁺ chelation in the rat carotid body (CB) glomus cells. HIF-1 bound to HIF-1 translocated into the nucleus is identified on the basis of immunohistochemistry and immunofluorescence. In Nx, a weak expression of HIF-1 was observed in CB glomus cells. However, exposure of CB and glomus cells to Hx (Po₂7 Torr) and Nx with ciclopirox olamine (CPX, 5 M) for 1 h showed a significant (P<0.001) increase in HIF-1 protein. The CBs and glomus cells exposed to Nx, Hx, and Nx with CPX showed a constant level of HIF-1 protein expression. HIF-1 subunit is continuously synthesized and degraded under normoxic conditions, while it accumulates rapidly following exposure to low oxygen tensions. Hydroxylation of HIF-1 by prolyl hydroxylase for proteasomal degradation was dependent on iron, 2-oxoglutarate, and oxygen concentration. The intracellular iron that acts as a cofactor for prolyl hydroxylase activity belongs to the labile iron pool and can be easily chelated. Thus, chelation of intracellular labile iron by CPX in Nx significantly increased HIF-1 in CB glomus cells. Thus, the results are consistent with the hypothesis that HIF-1 which is present in the glomus cells translocates to the nucleus during exposure to Hx and to CPX in Nx.     

A simple brassinolide analogue 2α, 3α-dihydroxy-17β-(3-methyl-butyryloxy)-7-oxa-B-homo-5α-androstan-6-one which induces bean second internode splitting

A new synthetic brassinolide analogue, 2,3-dihydroxy-17-(3-methylbutyryloxy)-7-oxa-B-homo-5-androstan-6-one (11), has been shown to exhibit typical brassinolide activity characterised by elongation, swelling, twisting and splitting of the bean second internode. It was prepared from the known lactone 2,3,17-trihydroxy-7-oxa-B-homo-5-androstan-6-one (4) which was transformed to an isopropylidenedioxy derivative. After protection of the 2- and 3-hydroxy groups it yielded the 2,3-isopropylidenedioxy-17-(3-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one (7) on treating with 3-methylbutyryl chloride in pyridine. The analogue with a 2-methylbutyric moiety (10, 2,3-dihydroxy-17-(2-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one) in position 17 stimulated only elongation and swelling of the bean second internode. However, in this bioassay 100 times more 10 or 11 compared to 24-epibrassinolide is required to obtain the same effects. Analogues with -oriented hydroxyl groups at C-2 and C-3 (14,15), a 6-ketone (17,18) or 6-oxa-7-oxo-lactone system (12,13) in ring B lack the typical brassinolide activity. In addition, the active brassinosteroids applied to the second internode stimulated a similar, but 30% lower elongation of the first internode. From data presented here we conclude that the presence of two hydroxy groups in the positions 22 and 23 of the brassinolide side chain, which are considered as a key structural requirement, is not absolutely necessary for a compound to exhibit typical brassinosteroid activity. Nevertheless, these compounds have generally 2–10 times lower activity than that having 22,23-vicinal diol in the side chain.     

Laboratory culture studies of Trichodesmium isolated from the Great Barrier Reef Lagoon, Australia

Cultures of Trichodesmium from the Northern and Southern Great Barrier Reef Lagoon (GBRL) have been established in enriched seawater and artificial seawater media. Some cultures have been maintained with active growth for over 6years. Actively growing cultures in an artificial seawater medium containing organic phosphorus (glycerophosphate) as the principal source of phosphorus have also been established. Key factors that contributed to the successful establishment of cultures were firstly, the seed samples were collected from depth, secondly, samples were thoroughly washed and thirdly, incubations were conducted under relatively low light intensities (PAR 40–50molquantam^–2s^–1). N₂ fixation rates of the cultured Trichodesmium were found to be similar to those measured in the GBRL. Specific growth rates of the cultures during the exponential growth phase in all enriched media were in the range 0.2–0.3day^–1 and growth during this phase was characterised by individual trichomes (filaments) or small aggregations of two to three trichomes. Characteristic bundle formation tended to occur following the exponential growth phase, which suggests that the bundle formation was induced by a lack of a necessary nutrient e.g. Fe. Results from some exploratory studies showed that filament-dominated cultures of Trichodesmium grew over a range of relatively low irradiances (PAR 5–120molquantam^–2s^–1) with the maximum growth occurring at 40–50molquantam^–2s^–1. These results suggest that filaments of the tested strain are well adapted for growth at depth in marine waters. Other studies showed that growth yields were dependent on salinity, with maximum growth occurring between 30 and 37psu. Also the cell yields decreased by an order of magnitude with the reduction of Fe additions from 450 to 45nM. No active growth was observed with the 4.5nM Fe addition.     

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.     

The distribution of glutamate-like immunoreactivity in the thoracic and abdominal ganglia of the locust (Schistocerca gregaria)

The distribution of glutamate-like immunore-activity in the thoracic and abdominal ganglia of the locust was studied using two polyclonal antibodies against glutamate. Because glutamate is a precursor of the inhibitory transmitter -amino butyric acid (GABA) the distribution of immunostaining by antibodies against glutamate and GABA was closely compared in adjacent serial sections. When the antibodies were used at optimal dilutions there was no overlap in the distribution of immunostaining for glutamate and GABA. In the pro- and mesothoracic ganglia 360–400 somata are immunoreactive for glutamate, while in the metathoracic ganglion about 600 somata were stained. These range in diameter from 10–100 m in diameter and include the majority of the large somata in these ganglia. Bundles of primary neurites emerging from these large somata can be traced through the neuropile. Most of the bundles correspond to the known paths of motor neurone primary neurites. In addition the T-tract is also immunolabelled. The free abdominal ganglia each contain 80–100 somata ranging in size from 10–45 m while the terminal ganglion contains about 250 somata, 10–60 m in diameter.