Biomass and primary production of Cladophora glomerata (L.) Kütz. in the Neva Estuary

The dynamics of the biomass, primary production, and P/B ratio of floating and attached forms of green filamentous alga Cladophora glomerata (L.) Kütz. was studied for the shallow water littoral area of the Neva Estuary in 2003–2006. The biomass of the floating algae constituted up to 70% of the total biomass, and the primary production reached up to 90% of the total for the depths of 0–1 m from the middle of July to the end of August.     

Accumulation,degradation and biological effects of lindane on Scenedesmus obliquus (Turp.) Kütz

A study was made of accumulation, degradation and biological effects of lindane (r-BHC) on Scenedesmus obliquus (Turp.) Kütz. The work was conducted in a sewage reservoir in Han-Ku, Tianjin. Experimental results show that at 0.1–10 mgl⁻¹ concentration of lindane, the growth, chlorophyll and carotene content in S. obliquus do not differ much from the control. At concentrations of 50–100 mgl⁻¹, however, growth is inhibited, and chlorophyll and carotene content is low. From the beginning of the experiment until the fifth day, growth rate and pigment content increase constantly. On the seventh day, they start to decrease. Spectrographic analysis shows that pigment content decreases, but pigment structure is not changed even at high concentration of lindane. At 1–10 mgl⁻¹ of lindane, amino acids remain unchanged, with the exception of aspartine, arginine, methionine and phenylalanine. Scenedesmus obliquus (Turp.) Kütz possesses a certain accumulating capacity for r-BHC, which is higher at 1 mgl⁻¹ than at 10 mgl⁻¹. Accumulation is enhanced with time and is better under turbulent conditions. Gas chromatograms show that after treatment for 24 h, there are two more peaks at retention time 1′32″ and 1′53″, respectively, suggesting that a certain degree of lindane degradation occurs. The nature of these degradation products awaits further study. As a conclusion S. obliquus (Turp.) Kütz holds promise in the treatment of lindane-containing wastewaters in the range of 1–10 mgl⁻¹.     

Effect of Photon Fluence Rate and Specific Growth Rate on Geosmin Production of the Cyanobacterium Oscillatoria brevis (Kütz.) Gom

The production of geosmin from the cyanobacterium Oscillatoria brevis was studied as a function of the photon fluence rate and appears to be related to the chlorophyll content.     

On a new cytological race of schizomeris leibleinii Kütz

Schizomeris leibleinii Kütz was collected from Dehra Dun as well as from Varanasi and the observations on its morphology, asexual reproduction and cytology were made by using material from nature and in culture. Cultural studies have revealed some interesting features such as occasional branching of uniseriate as well as multiseriate filaments and extensive development of the holdfast lobes into uniseriate or multiseriate filaments which may sometimes be branched. The chromosome number for the present alga has been determined to be 14, which differs from three earlier chromosome numbers reported for the same species by previous workers. Besides differing in chromosome number, it also differs significantly in its karyotype as compared with others. Thus this alga is considered to be a new chromosomal race of S. leibleinii. The present observations which have been discussed in the light of the recent work of Campbell & Sarafis (1972) who proposed a merger of Schizomeris with Stigeoclonium tenue, do not seem to favour such a merger.     

Kinetics of urea uptake by Melosira italica (Ehr.) Kütz at different luminosity conditions

The kinetic parameters K_m and V_max for urea uptake by Melosira italica were determined at 160 μeinsteins m⁻² s⁻¹ and in the dark. The transport systems showed an affinity for the substrate and a storing capacity in the dark (K_m = 65.07 μM; V_max = 2.18 nmoles 10⁵ cells ⁻¹ h⁻¹) greater than under 160 μE m⁻² s ⁻¹ (K_m = 111.2 μM; V_max = 1.11 nmoles 105 cells⁻¹ h⁻¹). Similarly, a reduction in consumption rate of urea under increasing photon flux densities was observed. The use of an inhibitor (potassium cyanide) indicated that the uptake process requires metabolic energy. That urea transport is more important in darkness, may constitute a survival strategy in which this compound is utilized by cells mainly during heterotrophic growth.     

Effect of external CO2 concentrations on protein synthesis in the green algae Scenedesmus obliquus (Turp.) Kütz and Chlorella vulgaris (Kosikov)

Unicellular algae grown under low-CO₂ conditions (0.03% CO₂) have developed a means of concentrating CO₂ at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase. Cells with the CO₂-concentrating mechanism (CCM) acquire the ability to accumulate inorganic carbon to a level higher than that obtained by simple diffusion. To identify proteins which are involved in the organization of the CCM, cells of Scenedesumus obliquus and Chlorella vulgaris grown in high CO₂ (5% CO₂ in air) were transferred to low-CO₂ (0.03%) conditions in the presence of ³⁵SO _inf4 ^sup2? and, thereafter, polypeptides labeled with ³⁵S were detected. Under low-CO₂ conditions the inducton of 36-, 39-, 94- and 110- to 116kDa polypeptides were particularly observed in S. obliquus and 16-, 19-, 27-, 36-, 38- and 45-kDa polypeptides were induced in C. vulgaris. Western blots with antibodies raised against 37-kDa subunits of the periplasmic carbonic anhydrase (CA) of Chlamydomonas reinhardtii showed immunoreactive bands with the 39-kDa polypeptide in the whole-cell homogenates from S. obliquus and with 36 and 38-kDa polypeptides in both high- and low-CO₂grown cells of C. vulgaris. Anti-pea-chloroplast CA antibodies cross-reacted with a single polypeptide of 30 kDa in the whole-cell homogenates but not with thylakoid membranes. The CA activity was associated with soluble and membrane-bound fractions, except thylakoid membranes.     

NaCl induced changes in photosystem stoichiometry and photosynthetic activity of the cyanobacterium Microcystis aeruginosa Kütz

Exposure to 0.4 M NaCl resulted in higher PS I/PS II stoichiometry and increase in the rate of photosynthesis in planktonic cyanobacterium M. aeruginosa. Altered ratios of PS I/PS II as well as photosynthesis and respiration were stabilized within 72 hr of exposure to salt, leading to adaptation of the organism to the changed conditions.     

Cyanobacterium Nostoc paludosum Kütz as a basis of creation of agriculturally useful microbial associations by the example of bacteria of the genus Rhizobium

Different species of Rhizobium were successfully introduced into the extracellular slime of Nostoc paludosum (Kütz) Elenk, strain 18; cyanobacteria did not eliminate them and exhibited no specificity to the introduced species. Both partners were shown to exist in a self-sufficient manner in an artificial consortium, the stability of which is determined by the technology of growing the cultures in collections. Cyanobacteria act as carriers of introduced satellites, providing contact with the inoculated material through the slime, and increase the nitrogen-fixing ability of legume plants due to the increase of the number and activity of nodules. The fact of penetration of cyanobacterial hormogonia into the nodules has been noted. The treatment of seeds by the consortium resulted in an increase of the harvest as compared with the standard methods of nitragin treatment of legumes.     

The assembly of cellulose microfibrils in Valonia macrophysa Kütz

The assembly of cellulose microfibrils was investigated in artificially induced protoplasts of the alga, Valonia macrophysa (Siphonocladales). Primary-wall microfibrills, formed within 72 h of protoplast induction, are randomly oriented. Secondary-wall lamellae, which are produced within 96 h after protoplast induction, have more than three orientations of highly ordered microfibrils. The innermost, recently deposited micofibrils are not parallel with the cortical microtubules, thus indicating a more indirect role of microtubules in the orientation of microfibrils. Fine filamentous structures with a periodicity of 5.0–5.5 nm and the dimensions of actin were observed adjacent to the plasma membrane. Linear cellulose-terminal synthesizing complexes (TCs) consisting of three rows, each with 30–40 particles, were observed not only on the E fracture (EF) but also on P fracture (PF) faces of the plasma membrane. The TC appears to span both faces of the bimolecular leaflet. The average length of the TC is 350 nm, and the number of TCs per unit area during primary-wall synthesis is 1 per m². Neither paired TCs nor granule bands characteristic of Oocystis were observed. Changes in TC structure and distribution during the conversion from primary- to secondary-wall formation have been described. Cellulose microfibril assembly in Valonia is discussed in relation to the process among other eukaryotic systems.Abbreviations TC terminal complex - EF E (outer leaflet) fracture face of the plasma membrane - PF P (inner leaflet) fracture face of the plasma membrane - MT microtubule - PS protoplasmic surface of the membrane     

Nutrient induced changes in the species composition of epiphytes on Cladophora glomerata Kütz. (Chlorophyta)

Cladophora glomerata is a widely distributed filamentous freshwater alga that hosts a complex microalgal epiphyte assemblage. We manipulated nutrients and epiphyte abundances to access their effects on epiphyte biomass, epiphyte species composition, and C. glomerata growth. C. glomerata did not grow in response to these manipulations. Similarly, nutrient and epiphyte removal treatments did not alter epiphyte biovolume. Epiphyte species composition, however, changed dramatically with nutrient enrichment. The epiphyte assemblage on unenriched C. glomerata was dominated by Epithemia sorex and Epithemia adnata, whereas the assemblage on enriched C. glomerata was dominated by Achnanthidium minutissimum, Nitzschia palea and Synedra spp. These results indicate that nutrients strongly structure epiphyte species composition. Interactions between C. glomerata and its epiphytes were not affected by epiphyte species composition in our experiment but may be when C. glomerata is actively growing.     

Phycobilisome from Anabaena Variabilis Kütz. and its Model Conjugates

The model conjugates phycocyanin-allophycocyanin (C-PC-APC) and phycoerythrocyanin-phycocyanin-allophycocyanin (PEC-C-PC-APC) were synthesized by using a heterobifunctional coupling reagent N-succinimidyl-3-(2-pyridyldithio)propionate. The rod-core complex (αβ)₆ ^PCL_RC ²⁷(αβ)₃ ^APCL_C ^8.9 and phycobilisomes were separated from Anabaena variabilis. Energy transfer features for the conjugates and the complexes were compared. The absorption and fluorescence emission spectra indicated that the linker-peptides mediate interaction of phycobiliproteins and prompt energy transfer. The energy transfer in the conjugates was detected by fluorescence emission spectra and confirmed by the addition of dithiothreitol. The conjugates may be used as models for studying the energy transfer mechanism in phycobilisomes. This revised version was published online in September 2006 with corrections to the Cover Date.     

Phykochronologische Untersuchungen in Assoziationen von Laminaria digitata (L.) Lamour. f. stenophylla (Kütz.) Harv. an der norwegischen Westküste

Zusammenfassung Die Natur der konzentrischen Zonen in den Stämmen von Laminarien ist lange Zeit umstritten gewesen. Nachdem aber im Jahre 1926 nachgewiesen wurde, daß das gesamte vegetative Wachstum bei den nordischen, regelmäßig blatterneuernden Laminarien periodisch und synchron in allen Teilen der Pflanzen erfolgt, war damit bewiesen, daß diese Zonen wirkliche Jahresringe darstellen, die im Zusammenhang mit dem jährlichen Blattwechsel stehen.Ebenso wie die Dendrochronologie die Jahresringe der Bäume als Grundlage für forstliche Untersuchungen über Bestockung, Alter, Produktions- und Verjüngungsverhältnisse im Waldbau benutzt, kann man aus den Jahresringen der nordischen Laminarien entsprechende Rückschlüsse ziehen.Bei der stetig steigenden Nutzbarmachung und Verwendung der Meeresalgen sind derartige Gesichtspunkte von aktuellem Interesse in der Algologie geworden.Vorliegende Arbeit ist ein Versuch, eine Bestandsanalyse in phykochronologischer Regie durchzuführen mit besonderer Berücksichtigung etwaiger Schwankungen in Assoziationen von Laminaria digitata f. stenophylla hinsichtlich Repopulation, Bestockung, Wachstumsverhältnissen und anderer damit verknüpfter biologischer Fragen.Die Untersuchung wurde in den Jahren 1955–1958 an der norwegischen Westküste vorgenommen.Es sei darauf hingewiesen, daß sowohl das vegetative Wachstum als auch die Repopulation bei der genannten Alge von Jahr zu Jahr innerhalb ausgedehnten Grenzen variieren kann und daß diese Pflanze eine nur kurze Lebensdauer hat. Exemplare von mehr als 6 Jahren wurde nicht angetroffen. Ihr Bestand wird deshalb recht rasch erneuert.Professor Dr. E. G. Pringsheim zum 80. Geburtstag gewidmet.     

两种新型农药对斜生栅藻(Scenedesmus obliquus Kütz.)的毒性研究

LY-04和WSQIF是由华中师范大学农药所合成的两种新型有机磷农药,LY-04属于α-氧代膦酸衍生物,WSQIF属于芳氧基乙酰氧基烃基膦酸脂.选用斜生栅藻(Scenedesmus obliquus Kütz.)作为实验生物,通过显微计数测定藻细胞的密度以计算LY-04和WSQIF对斜生栅藻24 h、48 h、72 h、96 h的半效应抑制浓度(EC50),研究其对斜生栅藻的毒性效应.结果表明以丙酮为溶剂时,每隔24 h取样,测得 LY-04对斜生栅藻的48 h、72 h、96 h的EC50值分别为2 942.5 mg/L、239.7 mg/L和65.0 mg/L,而WSQIF的24 h、48 h、72 h、96 h的EC50值分别为15.9 mg/L、53.0 mg/L、98.0 mg/L和28.8 mg/L.LY-04和WSQIF分别作为杀虫剂和除草剂而研制,经活体研究表明,LY-04具有较强的杀虫活性,WSQIF则具有很强的除草活性,所得EC50值基本符合设计结果.根据毒性分级标准,LY-04和WSQIF的EC50值远大于3 mg/L,其对非靶生物中的水生藻类都属于低毒,可推广应用.     

Temperature profiles of cellular growth and exopolysaccharide synthesis by Botryococus braunii Kütz. UC 58

Temperature profiles (range 20–33 °C) were obtained for growth and exopolysaccharide (EPS) biosynthesis of the microalga Botryococcus braunii strain UC 58 under photoautotrophic conditions. The maximum temperature for growth was 32 °C and the temperature dependence of the specific growth rate was described by the Hinshelwood equation based on the Arrhenius relationship. The optimal range of temperatures for growth and extracellular EPS synthesis (25–30 °C) concurred and production of 4.5–5 g l⁻¹ of EPS was obtained routinely, leading to high broth viscosities. Below 23 °C EPS biosynthesis was negligible, although the specific growth rate maintained high values. At supraoptimal temperatures EPS biosynthesis decreased, accompanying the increase in doubling time. The polymers formed at temperatures within the optimal range for production, when dissolved in water, produced solutions (2 gl⁻¹) with the highest viscosity, suggesting that their molecular weight showed the highest values. The degree of polymerization of the EPS synthesized at suboptimal and supraoptimal temperatures was significantly below the values within the optimal range.     

Seasonal studies on alginate and its composition II: Turbinaria conoides (J.Ag.) Kütz. (Fucales, Phaeophyceae)

The alginates extracted from ‘leaf’, ‘stem’ and entire thallus of Turbinaria conoides (J.Ag.) Kütz. were investigated for their viscosity and biochemical constituents namely, β-D-mannuronic acid (M-block}), α-L-guluronic acid (G-Block) and alternating sequences of β–D-mannuronic acid and α-L-guluronic acid (MG-block). Substantial seasonal variation was recorded with high yield of alginate during premonsoon. The yield of alginate was maximum in ‘leaf’ region. In contrast to this, viscosity and G-block were maximum in the ‘stem’ region. A significant positive correlation was observed between viscosity and G-block}. The ratio of guluronic: mannuronic acid was also assessed. Low levels of M/G ratio were recorded in the ‘stem’ region followed by ‘leaf’ and entire thallus.     

Silicon,a required nutrient for Cladophora glomerata (L) Kütz. (Chlorophyta)

Summary Physiological and ultrastructural studies of unialgal cultures demonstrated that silicon is a required nutrient and a component of the cell walls of Cladophora glomerata. Addition of silicon promoted growth of the alga, and the addition of germanium, an analogue of silicon, inhibited growth of C. glomerata in culture. An electron-dense outer layer was a conspicuous part of the cell walls of filaments taken from silicon rich medium.Abbreviation SWE soil water extract     

Lattice images from ultrathin sections of cellulose microfibrils in the cell wall of Valonia macrophysa Kütz.

The crystalline ultrastructure and orientation of cellulose microfibrils in the cell wall of Valonia macrophysa were investigated by means of high-resolution electron microscopy of ultrathin (approx. 28 nm) sections. With careful selection of imaging conditions, ultrastructural aspects of the cell wall that had remained unresolved in previous studies were worked out by direct imaging of crystal lattice of cellulose microfibrils. It was confirmed that each microfibril is a single crystal having a lateral dimension of 20·20 nm², because lattice images of 0.39 nm resolution were clearly recorded with no major disruption in the whole area of the cross section of the microfibril. There was no evidence for the existence of 3.5-nm elementary fibrils which have been considered to be basic crystallographic and morphological units of cellulose in general. It was also confirmed that the axial directions (crystallographic fiber direction) of adjacent microfibrils in each single lamella of the cell wall are opposite to each other.     

Dormancy and growth-inhibitor levels in oospores of Chara contraria A. Braun ex Kütz. (Charophyta)

Experiments on oospores of Chara contraria A. Braun ex Kutz. studied the correlation between dormancy and plant growth inhibitors. Fresh oospores, harvested from a drainage channel, showed a germination rate in vitro of 44–85%. Extracts from oospores harvested at the end of the summer contained inhibitory activity, which co-chromatographed with abscisic acid, but no inhibitors were detected in harvests from the beginning of the summer nor in oospores which lay dormant at the botton of the channel. No correlation between inhibitory activity and dormancy was detected. Our results support the hypothesis that the inhibitors detected play a role in the abscission of oospores from the mother plant.