Production of antibacterials from the freshwater alga Euglena viridis (Ehren)

The antibacterial properties of Euglena viridis, collected from a freshwater pond at the Central Institute of Freshwater Aquaculture (CIFA), Bhubaneshwar, India, were tested against various strains of virulent pathogens viz. Pseudomonas putida(PP1, PP2),P. aeruginosa (PA1, PA2, PA3, PA4), P. fluorescens (PF1, PF2, PF3, PF4), Aeromonas hydrophila (AH30, AH31, AH32, AH34), Edwardsiella tarda, Vibrio alginolyticus (VA1),V. anguillarum(VN1, VN2 & VN3), V. fluvialis (VF1), V. parahemolyticus (VP1) and V. harveyi (VH1) andEscherichia coli(O115, O1, O156, O164, O111 & O109). Four organic extracts viz. methanolic, ethanolic, acetone and acetone/ethanol of theE. viridis showed moderate to high antibacterial activity to all the bacterial pathogens. Rotavapor extraction products showed higher sensitivity in comparison to cold and hot extractions.     

Embryogenesis and plantlet development in the bamboo Phyllostachys viridis (Young) McClure

Leaf explants of Phyllostachys viridis (Young) McClure were cultured on Murashige and Skoog medium supplemented with 9×10^-6 M 2,4-dichlorophenoxyacetic acid. Numerous embryoids were observed. On transfer to Murashige and Skoog medium lacking hormones, plantlets developed within two weeks and were later successfully transferred to the field.     

Characterization of expressed pigmented core light harvesting complex (LH 1) in a reaction center deficient mutant of Blastochloris viridis

The utility of photosynthetically defective mutants in the purple photosynthetic bacterium Blastochloris viridis (formerly Rhodopseudomonas viridis)was demonstrated with construction of a reaction-center deficient mutant, LH 1-H. This LH 1-H mutant has a photosynthetic apparatus in which most of the puf operon genes were deleted, resulting in an organism containing only the genes for the light harvesting polypeptides and the H subunit of the reaction center. This B. viridisstrain containing a truncation of the puf operon was characterized by gel electrophoresis, lipid-to-protein ratio analysis, optical spectroscopy, electron paramagnetic resonance and transmission electron microscopy. Optical and electron paramagnetic resonance spectroscopies revealed no photoactivity in this LH 1-H mutant consistent with the absence of intact reaction centers. Electron paramagnetic resonance evidence for assembled LH 1 complexes suggested that the interactions between light harvesting polypeptide complexes in membranes were largely unchanged despite the absence of their companion reaction center cores. The observed increase in the lipid-to-protein ratio was consistent with modified interactions between LH 1s, a view supported by transmission electron microscopy analysis of membrane fragments. The results show that B. viridis can serve as a practical system for investigating structure-function relationships in membranes and photosynthesis through the construction of photosynthetically defective mutants. This revised version was published online in August 2006 with corrections to the Cover Date.     

Atypical foliar anatomy related to Kranz syndrome in Paspalum inaequivalve and Paspalum microstachyum (Poaceae: Panicoideae: Paniceae)

Paspalum L. is a large and complex genus, enclosing more than 300 species, whose boundaries and infrageneric classification are still being studied. Recent phylogenetic analyses suggest that Paspalum inaequivalve Raddi and Paspalum microstachyum J. Presl, from the Inaequivalvia informal group, should be excluded from Paspalum. Focused on the unclear taxonomic position of P. inaequivalve and P. microstachyum, their leaf anatomy was studied, and some atypical features related to C₄ photosynthesis were found. This atypical Kranz syndrome is the aim of this research. Transverse leaf blade sections from fresh and herbarium material of P. inaequivalve were studied by light, fluorescence, and transmission microscopy. Additionally, sheaths and culms of P. inaequivalve and leaf blades of P. microstachyum were observed by light microscopy. δ¹³C isotope discrimination was determinated for P. inaequivalve. We compared our results with available anatomical data from related taxa. As well as typical mesophyll cells (PCA) and mestome sheath cells (PCR), a third type of cells, here called ‘globose parenchymatous cells’, was observed in leaf blades of P. inaequivalve and P. microstachyum. These cells are placed externally to the mestome sheaths of the first and second vascular bundles, they have thin walls, with no developed suberine lamella, few chloroplasts with 1–2 starch grains, thylakoids not organized in grana, and a large central vacuole. The globose parenchymatous cells represent a novel trait in P. inaequivalve and P. microstachyum, further supporting the close relation between both species and their exclusion from the genus Paspalum. This atypical Kranz syndrome has not been described in Paspalum before, but the globose parenchymatous cells here described resemble the distinct cells considered as remnants of the outer parenchymatous sheath described for Anthaenantiopsis, some sections of Panicum L., and Chaetium Nees, providing possible taxonomic significance.     

Taxonomical investigations onHelleborus viridis s. l. (Ranunculaceae) in Northern Italy

The taxon commonly namedHelleborus viridis in Lombardy (NW. Italy) differs from both, subsp.viridis and subsp.occidentalis, and is shown to fall within the variation range ofH. odorus subsp.laxus which has been reported so far for NE. Italy only. TrueH. viridis within Italy grows only in the Maritime Alps.     

Ultrastructural aspects of leaves inFestuca ovina andPoa sphondylodes (C-3 Poaceae)

Structural aspects of the leaves of two common festucoids,Festuca ovina andPoa sphondylodes, have been examined employing the electron microscopy. The nature of vascular bundles and of sheaths that surround vascular tissues was discussed in the study. The festucoids exhibited a non-Kranz C-3 anatomy with more than four mesophyll cells separating the bundle sheaths of a leaf blade. Vascular tissues in theseFestuca andPoa leaves were surrounded by a double sheath: an inner distinct mestome sheath (MST) and an outer indistinctive layer of parenchymatous bundle sheath (PBS) cells. The PBS cells were much larger than the MST and had thin walls. The MST cells were relatively small and rectangular inP. sphondylodes and more or less hexangular in transverse sections ofF. ovina. InP. sphondylodes, MST had conspicuously thickened inner tangential walls with asymmetrically uninterrupted suberized lamellae in radial and tangential walls. In most differentiated MST cells, all walls were highly suberized. During suberin deposition, MST cells were quite vacuolated and most of the cytoplasm was present as a thin peripheral layer. However, MST walls inF. ovina revealed very thin suberized lamellae with translucent striations. No chloroplasts were detected inP. sphondylodes, whereas the MST inF. ovina contained small chloroplasts. Plasmodesmata were well developed in the primary pit fields of walls between MST and vascular cells, and between adjacent MST cells. Plasmodesmata were less frequent in the walls between the inner and outer sheath cells. Suberized lamellae were totally absent from the PBS cell walls in all veins. External to the PBS, the mesophyll comprised thin walled cells with abundant intercellular spaces. Peripherally arranged chloroplasts in the mesophyll were numerous and often larger than those of PBS and MST cells. Characteristics associated with C-3 and other ultrastructural features were also discussed in the study.     

Species-specific ability ofChlorella strains (Chlorophyceae) to form stable symbioses withHydra viridis

46 strains ofChlorella, identified by physiological and biochemical characters, were examined for their ability to form stable symbioses with aposymbioticHydra viridis. It was found to be a species-specific characteristic. Among the 15 taxa studied, onlyC. saccharophila var.ellipsoidea, C. saccharophila var.saccharophila, C. fusca var.vacuolata, C. kessleri, C. luteoviridis, andC. protothecoides formed stable symbioses withHydra viridis. Among the 11 known physiological and biochemical characters of theseChlorella species, only acid tolerance seems to be correlated with symbiosis: All symbiotic species are capable of growing at or below pH 4.0.     

Inheritance of some marker genes in Setaria italica (L.) P. Beauv.

Summary A study on a series of genetic markers was run on five hybrids of foxtail millet, Setaria italica, and on one interspecific hybrid S. viridisxS. italica (S. viridis is the wild relative of S. italica). Seven enzymatic systems were investigated using starch gel electrophoresis (esterase, alcohol dehydrogenase, glutamate oxaloacetate transaminase, acid phosphatase, malate dehydrogenase, 6-phosphogluconate dehydrogenase, cathodic peroxidase). This genetic analysis of the 6 F2 has allowed us to define 12 polymorphic loci: Est-1, -2 and -3, Adh-1, Got-1 and -2, Acph-1, Mdh-1 and -2, Pgd-1 and -2, and Pox-1. All of them behaved like dimers, except Est-1 and Est-2 which showed monomeric structures. Two other markers were examined: waxy endosperm, which appeared to be controlled by one locus, and anthocyanic pigmentation of the collar, for which at least two loci are responsible. Studies of linkage carried out on three F2 showed two linkage groups: Mdh-1, Pox-1, Wx, Est-3, and a locus for collar colour, and Est-2, and one or two other loci of colouring.     

Effect of Cadmium on Cellular Viability in Two Species of Microalgae (Scenedesmus sp. and Dunaliella viridis)

We determined the effect of several concentrations of cadmium (0, 5, 10, and 20 μg/l) on cellular viability in the microalgae Scenedesmus sp. and Dunaliella viridis, by measuring growth at 0, 24, 48, 72, and 96 h and pigment production at 10 days. Algae were obtained from the Nonvascular Plant Laboratory collection, in the Facultad Experimental de Ciencias, Universidad del Zulia, Venezuela. Growth was measured by cellular counting, while pigment content was evaluated using conventional spectrophotometric techniques. Growth of both species decreased in the exposed cultures comparing with the control, but its behavior was similar, because in both control and exposed cultures, its was observed an adaptive phase in the first hours, as well as a growth phase after 72 h. Cadmium concentrations above 10 μg/l produced an adverse effect on pigment production, depending on the concentration and/or exhibition time. However, even though cadmium inhibited growth and pigment production, levels of both parameters indicated cellular viability, demonstrating the adaptability of the algae cultures when they were exposed to the metal.     

Distribution and life cycle of the North American Spionid polychaeteMarenzelleria viridis (Verrill, 1873) in the Ems estuary

In 1983 the first specimens of the North American spionid polychaeteMarenzelleria viridis were found along the European mainland shore in the Ems estuary. Since then, this polychaete has spread over several estuaries around the North Sea and the Baltic. In the inner part of the Ems estuary juveniles were predominantly present in muddy sediments high in the intertidal zone; in more sandy sediments at higher salinities juveniles and adults co-occured. Detailed information was obtained at a muddy and at a sandy station. Gametes were present in the coelomic fluid from November through March. In May new recruits were found in the sediment samples, reaching densities of over 10⁵ M⁻² at the muddy station, andc. 2000 m⁻² at the sandy station. During summer, densities decreased at the muddy station, coinciding with a density increase at the sandy station, suggesting migration of juveniles from a nursery to the adult habitat. Cage experiments showed that the decrease of juveniles at the muddy station could be attributed to migration and not to mortality due to predation. At the sandy habitat palps and anterior parts ofM. viridis made up 4–11% of the stomach content of juvenile plaice (Pleuronectes platessa). In juvenile flounder (Platichthys flesus) only in Aprilc. 10% of the stomach content consisted ofM. viridis. During 1983–1990 increasing densities ofM. viridis at the sandy habitat coincided with a reduced abundance ofNereis diversicolor, however, this inverse relationship was not found to be statistically significant. Density fluctuations ofM. viridis andCorophium volutator showed a significant positive relationship, the cause of which is not yet understood.     

Weedy adaptation in Setaria spp. IV. Changes in the germinative capacity of S. faberii (poaceae) embryos with development from anthesis to after abscission

Studies were conducted evaluating germinability states in giant foxtail (Setaria faberii) embryos, as well as surrounding tissues (hull, caryopsis), with germination assays. Further, seed age, fascicle arrangement, flowering patterns, and elongation in the inflorescence were evaluated. Both qualitatitive and quantitative morphological observations of the hull and the caryopsis were revealed by precisely determined fertilized spikelet age from anthesis until after seed abscission. Red coloration of the placental pad at ≈ 11 d after anthesis is probably a morphological indicator of physiological maturity. Germinability of giant foxtail embryos changed with development. Four qualitatively different types of embryo germination were observed during development of the seed: early disorganized callus growth at the basal, coleorhizal end of the embryo; germination of immature embryos with shortened and thickened axes; germination of the scutellum; and germination and growth of the coleoptile and coleorhiza in embryos aged 7 d after anthesis and older. Axis-specific embryo germinability was also observed. Inhibition of the embryo could be localized to the coleoptile, the coleorhiza, or both. These studies provide evidence for a complex model of germinability regulation based on the independent, asynchronous actions of the embryo, caryopsis, and hull compartments, as well as on their dependent, synchronous action. These studies provide evidence for a dynamic, developmental model of giant foxtail germinability regulation resulting in phenotypes with a wide range of germinability shed from an individual panicle. These diverse germinability phenotypes are found at all stages of development, but particularly when the seed is shed and the soil seed bank is replenished.     

Seed and fruit anatomy ofCocculus hirsutus (Menispermaceae)

The ovules ofCocculus hirsutus are anatropous, bitegmic and, crassinucellate. The fruit is drupaceous, black purple, and laterally compressed and has a pericarp demarcated into exocarp and endocarp. The seeds are curved around the basal bodies. Testa and tegmen cells are thin-walled and unspecialized. In the ripe seed the inner epidermis of the tegmen persists, whereas the entire testa and the outer layer of the tegmen degenerate. Relationships of theMenispermaceae toRanunculaceae, Berberidaceae, andLardizabalaceae are supported.     

Ultrastructural analysis of sporoderm development in megaspores ofSelaginella galeottii (Lycophyta)

Structural members within the exospore ofSelaginella galeottii suggestive of those present at maturity are first detectable when the exospore is approximately 5 µm in thickness. Subsequent changes in successively larger sporangia involve a gradual size increase of the component units simultaneously throughout the exospore. Concomitantly, non-membrane bound material present at the inner surface of the tapetum (and the persistent megasporocytes) and throughout the sporangium locule changes from primarily droplets and weftlike material (including beaded wefts) to coarse fibrous material. The taxa which possess this unusual wall pattern cut across presently accepted taxonomic schemes. This is not the case with the other wall ultrastructural types in the genus. The possibility exists that this megaspore wall type defines a separate lineage within the genus which, by virtue of its large megaspores, was able to compete well and radiate to produce a variety of life forms.     

Accumulation, depuration and distribution of cadmium and zinc in the green-lipped mussel Perna viridis (Linnaeus) under laboratory conditions

Ecotoxicological tests were conducted in the green-lipped mussel Perna viridis under laboratory conditions. Different rates of accumulation and depuration in soft tissues are found and this might be due to different mechanisms of metal binding and regulation. At the end of depuration, Cd levels in soft tissues of P. viridis were 10–30 times higher than before exposure, while Zn levels in soft tissues were almost similar to levels before exposure. These results indicate that P. viridis is a good biomonitoring organism for Cd but Zn levels might be actively regulated. It remains uncertain whether P. viridis is a good biomonitoring organism of environmental Zn contamination. However, the positive patterns, although different rates, of accumulation and depuration for Cd and Zn support the use of P. viridis as a biomonitoring agent for such metals.     

Structure of thylakoids in cells of Rhodopseudomonas viridis as influenced by growth conditions

A vessel was constructed for growth of photosynthetic bacteria at defined light intensity, temperature and partial pressure of oxygen.Under growth conditions at light intensities larger than 1,000 lx, the particles exposed by freeze-fracturing of thylakoids are unordered.Under growth conditions at light intensities lower than 30 lx, the particles seen are hexagonally arranged. If the oxygen partial pressure is increased from 0 to 30 mm Hg while keeping the light intensity at 30 lx, the particles seen in the thylakoids are found to be unregularly arranged.The protein pattern of thylakoids isolated from bacteria grown either at 2,000 lx or at 30 lx revealed a constant ratio of reaction centre polypeptide to either of the membrane polypeptides of 8 kdalton apparent Mr and 12 kdalton apparent Mr.Dedicated to Prof. Dr. G. Drews on occasion of his 60th birthday     

A serine protease inhibitor from hemolymph of green mussel, Perna viridis

Bioactivity guided fractions of cell-free hemolymph of bacterially challenged marine mussel, Perna viridis led to the isolation of a novel quaternary alkaloid 1, which was identified by its spectral data. The isolated molecule 1 has been found to be a potent serine protease inhibitor (SPI) showing IC₅₀ and K_i values of 102.5 and 97.1–104.68 μM, respectively. The E_t/K_i value of SPI is 6.3, whereas E_t/K_m value is 1.04. The Van’t Hoff analysis showed that the value of K_i decreases with increase in temperature, and the binding of the inhibitor is entropically driven.     

阔鳞瘤蕨(水龙骨科)卵细胞发育超微结构观察

水龙骨科是蕨类植物中最进化的类群,该文采用超微技术对水龙骨科的阔鳞瘤蕨(Phymatosorus hainanensis)卵发育过程进行观察,以完善薄囊蕨植物卵发生的资料,为揭示蕨类植物的有性生殖及演化机制奠定基础。结果表明:(1)幼卵、颈沟细胞、腹沟细胞通过胞间连丝紧密连接。(2)发育过程中,卵与腹沟细胞之间细胞壁显著加厚,将卵细胞与腹沟细胞隔离。(3)在壁的下方产生分离腔,内含大量不定形物质,但卵细胞与腹沟细胞在中间处始终相连。(4)分离腔中的不定形物质沉积在卵细胞质膜外形成了一层加厚的卵膜,而在连接区(孔区)处不形成卵膜,该位置最终形成了受精孔。(5)卵细胞核变得高度不规则,近成熟时卵核产生了大量的核外突。     

Floral anatomy ofHypseocharis (Oxalidaceae) with a discussion on its systematic position

The floral anatomy of threeHypseocharis spp. has been studied. The genus resemblesOxalidaceae as well asMonsonia andSarcocaulon of theGeraniaceae. As it is closer toGeraniaceae than toOxalidaceae, it perhaps serves as a connecting link between them.     

Morphology, anatomy, and taxonomic position of Pagameopsis (Rubiaceae-Rubioideae)

Morphological and anatomical features (including wood anatomy and pollen morphology) of the small neotropical genusPagameopsis (Rubiaceae-Rubioideae) are discussed and illustrated. The fused ovaries, fenestrate corolla tube, basally attached anther filaments, and absence of raphides are especially noteworthy.Pagameopsis is definitely not a member of the Psychotrieae because of significant differences in wood anatomy and gynoecial and fruit structure. A close affinity with Gaertnereae seems doubtful for similar reasons. The taxonomic affinities ofPagameopsis remain obscure. The genus shows similarities with several taxa of the Rubioideae, such as Coccocypseleae, Morindeae, Hedyotideae, andMetabolos. The absence of raphides, on the other hand, makes a position in the Rubioideae doubtful.     

Influence of temperature and nitrogen concentration on photosynthesis ofDunaliella viridis Teodoresco

The photosynthetic behaviour ofDunaliella viridis has been studied under a combination of three variables: irradiance (0–900 mol m^–2 s^–1), temperature (15, 23, 31, 38, 42 °C) and nitrogen concentration (0.05, 0.5, 1.5, 5, 10 mM NO ₃ ^- ) at a salinity of 2 M NaCl.The highest rates of photosynthesis have been found at 31 °C and a nitrate concentration of 10 mM. There exists a synergistic effect between temperature and nitrogen availability on the photosynthesis ofD. viridis; under nitrogen deficiency oxygen evolution is low, even null at high temperature. The interaction between these two variables of control occurs in a multiplicative way. There is also a general increase in photosynthetic pigments following the increase in nitrogen concentration in the culture medium. The normalization of net photosynthesis data in relation to chlorophylla shows that nitrogen concentration makes an indirect control of the photosynthetic rate ofD. viridis through the variation of pigment concentration.