AUTOINHIBITION OF SPORE GERMINATION IN NOSTOC SPONGIAEFORME (CYANOPHYCEAE)1

Medium in which cultures of Nostoc spongiaeforme Ag. have sporulated contains one or more substances which inhbit the germination of spores (akinetes) of this organism. Germination of spores occurs rapidly in the absence of these substances, but is virtually completely suppressed in their presence.     

培养条件下发菜细胞超微结构的观察

通过观察发菜(Nostoc flagelliforme Born.et Flah.)细胞在不同生长条件的超微结构,探讨细胞的生长和发育特点以及胶质鞘的形成规律。在蒸馏水中浸泡2h后,各种细胞代谢活跃,能进行正常的生长和分裂,其中营养细胞的细胞壁以及一特殊类型的大细胞与胶质鞘的形成有关。在pH7.0的培养液中,出现与胶质鞘有关的细胞结构。在酸性培养液中未见这些结构。在不合适的pH条件下,一特殊类型的小细胞大量增殖。     

A natural terrestrial biofilm

Material recovered from an extensive and viscous biofilm found on areas of rough hill pasture in Southern Scotland proved to consist of a thick mucilaginous deposit of polysaccharide in which species of green algae, withGleocystis spp as the dominant microorganism and lesser numbers ofOocystis spp. Cyanobacteria were also entrapped. On laboratory culture other green algal and cyanobacterial species were detected. Analysis of the native polysaccharide and of the exopolysaccharide from a mixed culture of the dominant algal species derived from the original material, revealed the major components as glucose, galactose, mannose and rhamnose. The content of uronic acids was very low. The viscosity of the polysaccharide preparations was determined and compared with bacterial biofilm material; viscosity was lost following phenol extraction indicating that the original material was probably closely associated with proteins.     

Occurrence of airborne algae within the township of Bukit Jalil in Kuala Lumpur,Malaysia

There have been relatively few studies on airborne algae although they are known to have health implications. The aim of this study was to conduct a survey on the distribution of airborne algae within Bukit Jalil in Kuala Lumpur, Malaysia. The sampling sites included a quiet residential area, a busy area with high human movement, a highway with heavy traffic, small roads with low traffic, a golf course, two hilly areas, and the man-made lake, Tasik Komanwel. Soils were also collected from these sites when possible. Results based on cultured samples showed that cyanobacteria were the dominant airborne algae, with a total of eight species identified. The dominant species was Phormidium tenue while other airborne algae found included P. retzii, Nostoc commune, and N. linckia. The sites with high percentage occurrence of airborne algae were near the animal holding facility of the International Medical University and the Light Railway Transit station. Human movement could be an important factor affecting the occurrence of airborne algae. A very low occurrence of airborne algae was recorded at the sites around the lake area. Some of the airborne algae were also found in the soil samples, suggesting that the algae could originate from the soil.     

A Study of the Effect of Red Mud Amendments on the Growth of Cyanobacterial Species

Red mud is a bauxite residue, a by-product of the Bayer process for extraction of alumina from bauxite ore. It is highly alkaline in nature and contains heavy metal oxides and a variety of minor trace elements. Its disposal is the paramount environmental issue in alumina refining. Establishment of vegetation on red mud dumping sites is difficult because of alkaline pH and high concentrations of soluble ions and toxic compounds. The bioremediation of red mud seems to be a realistically convenient way for environmentally safe disposal of this industrial residue. The present study specifically deals with the utilization of cyanobacteria to bioremediate red mud. Being predominantly a nitrogen-fixing photosynthetic microorganism, it has considerable potential for bioremediation of bauxite residue. As a prelude step, four cyanobacterial species, viz. Oscillatoria sp., Lyngbya sp., Phormidium sp., and Microcystis sp. were selected to study their capability to grow on red mud–amended medium. The results indicate that Oscillatoria and Phormidium performed well on red mud–amended medium, followed by Lyngbya. Growth of Microcystis was inhibited significantly even at lower concentrations of red mud amendments. These findings point out the potential of these microorganisms, to be utilized as active biological agents for bioremediation of red mud.     

叶绿体陪伴蛋白在几种藻类中的存在和分布

用豌豆叶绿体陪伴蛋白（ｃｈ－ｃｐｎ６０）的杭体对衣藻和多种蓝藻细胞提取液作Ｗｅｓｔ－ｅｒｎｂｌｏｔ分析表明：真核的衣藻和原核的有异形胞丝状蓝藻的一种鱼腥藻中存在一种与豌豆ｃｈ－ｃｐｎ６０抗体有交叉反应的蛋白,其一个亚基的分子量与豌豆该蛋白的分子量相似,而另一亚基的分子量高于豌豆的β亚基分子量。绿藻和丝状蓝藻中这一蛋白在热处理后含量增加,而经－２０℃冷处理１２ｈ后含量明显下降。在单细胞蓝藻中则检测不到这种蛋白。     

Light absorption and scattering by cell suspensions of some cyanobacteria and microalgae

Absorption spectra of cyanobacteria (Anacystis nidulans, Anabaena variabilis, and Chlorogloeopsis fritschii), red (Cyanidium caldarum and Porphyridium cruentum), green (Dunaliella maritima and Dunaliella salina) and diatom (Thalassiosira weisflogii) alga cell suspensions are presented; the spectra were obtained by using an approach developed earlier to compensate for scattering [1, 2]. In all species, the shapes of the absorption spectra were independent of the cell concentration. For Th. weisflogii and D. maritima, the analysis of selective and nonselective scattering was carried out. The effect of mechanical cell disruption on optical properties (absorption, scattering, and “package” effect) on D. maritima was studied. The character and dynamics of optical changes in D. salina under the influence of sodium chloride were followed.     

A NUMERICAL TAXONOMIC STUDY OF NOSTOC AND ANABAENA1

Thirty characteristics of 14 Nostoc and 10 Anabaena species were analyzed from previously published data. Using standard numerical taxonomic methods, simple matching coefficients were calculated and a phenogram drawn. The analysis revealed that some of the central characteristics of Nostoc are: a punctiforme stage; motile reproductive stage; plant mass with a dull to shiny luster, non-veined surface, and nonfimbriate margin; some spherical vegetative cells; no cylindrical heterocysts; and some spherical, but no cylindrical akinetes. Some of the central characteristics of Anabaena that were revealed are: no punctiforme stage; a motile vegetative stage; plant mass with a shiny luster, veined surface, and fimbriate margin; no spherical vegetative cells; some cylindrical heterocysts; and some cylindrical, but no spherical, akinetes. In general, Anabaena has larger akinetes and vegetative cells than Nostoc. Based on 30 morphological characteristics and the clustering data of the phenogram, keys were constructed for the Nostoc and Anabaena species studied. The data clearly support two separate and distinct, though similar genera and, less sharply, the separation of the 24 species. The more useful characteristics for separation of the species are size and shape of akinetes, vegetative cells, and heterocysts; color and luster of plant mass; veined plant mass surface; margin fimbriate; and shape of plant mass in nature.     

DEVELOPMENT OF THE FLAGELLAR APPARATUS AND FLAGELLAR ORIENTATION IN THE COLONIAL GREEN ALGA GONIUM PECTORALE (VOLVOCALES)1

Vegetative cells of Gonium pectorale have a fine structure similar to that of Chlamydomonas. In addition, three zones comprise an extracellular matrix; a fibrillar sheath and tripartite boundary surround individual cells, and a fragile capsule zone surrounds the entire colony. Cytokinesis is accomplished by a phycoplast and cleavage furrow. The flagellar apparatus of the immature vegetative cell of this colonial alga is similar to that of Chlamydomonas, but the basal bodies are slightly separated at their proximal ends. The four microtubular rootlets alternate between two and four members. During development, the basal bodies become further separated and nearly parallel. The distal fiber is stretched, but it remains attached to both basal bodies. At maturity, the basal bodies of peripheral cells of the colony have rotated in opposite directions on their longitudinal axes resulting in a displacement of the distal fiber to one side, an asymmetrical orientation of the rootlets and loss of 180° rotational symmetry. Central cells remain similar to Chlamydomonas in that basal bodies do not rotate, rootlets are cruciate, the distal fiber remains medially inserted and 180° rotational symmetry is conserved. A “pin-wheel” configuration of flagellar pairs and the orientation of parallel rootlets toward the colony perimeter probably accounts for the rotation of the colonies during forward swimming. In addition, these ultrastructural features support the traditional placement of G. pectorale as an intermediate between the unicellular Chlamydomonas and the more complex colonial volvocalean genera.     

广东省鼎湖山钼矿区亚气生蓝藻的反射光谱特性

亚气生蓝藻（Ｃｙａｎｏｐｈｙｃｅａｅ）的反射光谱,在反射红外谱区（７７０—１０００ ｎｍ ）缺少绿色种子植物的高反射平台峰,反射率曲线平缓． 在矿体含钼量不同的矿化土壤上生长的亚气生蓝藻和矿区外缘正常土壤上生长的亚气生蓝藻,不但其细胞富集钼与矿化土壤的含钼量呈正相关关系,而且,亚气生蓝藻反射率与蓝藻细胞含钼量也呈正相关关系．在反射红外区矿化土壤上生长的钼矿蓝藻反射率明显地较矿区外缘正常土壤上生长的蓝藻高１３％ —２７％     

Biotransformations of monoterpenes by photoautotrophic micro‐organisms

Monoterpenes are widely used in food technology, cosmetic and pharmaceutical industries and as compounds of agricultural importance. It is known that compounds comprising this class can be transformed by a variety of organisms, namely by: bacteria, fungi, yeasts, plants or isolated enzymes. Biotransformations, as one of the most important tools of green chemistry, allow obtaining new products using whole cells of micro‐organisms or isolated enzymes in mild reaction conditions. Therefore, biotransformations of monoterpenes, by different type of reaction such as: epoxidation, oxidation and stereoselective hydroxylation, resulted in the production of so desired, enantiomerically defined compounds that can be advised as natural seem to be interesting. Bearing in mind that such processes are carried out also by easy to maintain, photoautotrophic micro‐organisms cultivated at large scale, this paper is focused on biotransformations of acyclic, monocyclic and bicyclic monoterpenes by freshwater or haliphylic cyanobacteria and microalgae on the way of mainly stereoselective hydroxylation. Moreover, aspects of potential industrial application of obtained products in medicine, perfume, cosmetics and food industry are discussed.     

Antibiotic activity of new cyanobacterial isolates from Australia and Asia against green algae and cyanobacteria

One hundred and ninety-eight cyanobacterial strains, newly isolated mainly from samples collected from diverse habitats in Australia, Indonesia, Nepal, Thailand and Vietnam, were screened from their antibiotic activity against green algal species of the genera Coelastrum, Scenedesmus and Monoraphidium. We report the discovery of ten strains of Fischerella, seven of Nostoc and three of Calothrix that produce antialgal compounds with a broad activity spectrum. Some of these bioactive cyanobacteria inhibited all three algae, whereas others inhibited only two, and some only one. In addition, the 20 active strains were tested against other selected cyanobacteria, including Anabaena doliolum which grows well both photoautotrophically in light and heterotrophically in darkness, and three toxic species, Microcytis aeruginosa, Anabaena circinalis and Nodularia spumigena, which are problems in Australia and other parts of the world. At least one Fischerella strain had bioactivity directed against photosynthetic electron transport of algal chloroplasts, whereas others had no effect on photosynthesis. In most cases the growth inhibitory effects were also tested in the presence of a proteinase. The results are discussed in the light of the possible nature of the chemical inhibition and also in relationship to competition and allelopathy in algal populations. This revised version was published online in June 2006 with corrections to the Cover Date.     

MICROENVIRONMENTS AND MICROSCALE PRODUCTIVITY OF CYANOBACTERIAL DESERT CRUSTS1

We used microsensors to characterize physicochemical microenvironments and photosynthesis occurring immediately after water saturation in two desert soil crusts from southeastern Utah, which were formed by the cyanobacteria Microcoleus vaginatus Gomont, Nostoc spp., and Scytonema sp. The light fields within the crusts presented steep vertical gradients in magnitude and spectral composition. Near-surface light-trapping zones were formed due to the scattering nature of the sand particles, but strong light attenuation resulted in euphotic zones only ca. 1 mm deep, which were progressively enriched in longer wavelengths with depth. Rates of gross photosynthesis (3.4–9.4 mmol O₂·m^?2·h^?1) and dark respiration (0.81–3.1 mmol O^?2·m^?2·h^?1) occurring within 1 to several mm from the surface were high enough to drive the formation of marked oxygen microenvironments that ranged from oxygen supersaturation to anoxia. The photosynthetic activity also resulted in localized pH values in excess of 10, 2–3 units above the soil pH. Differences in metabolic parameters and community structure between two types of crusts were consistent with a successional pattern, which could be partially explained on the basis of the microenvironments. We discuss the significance of high metabolic rates and the formation of microenvironments for the ecology of desert crusts, as well as the advantages and limitations of microsensor-based methods for crust investigation.     

New lipid‐producing,cold‐tolerant yellow‐green alga isolated from the rocky mountains of colorado

A new strain of yellow‐green algae (Xanthophyceae, Heterokonta), tentatively named Heterococcus sp. DN1 (UTEX accession number UTEX ZZ885), was discovered among snow fields in the Rocky Mountains. Axenic cultures of H. sp. DN1 were isolated and their cellular morphology, growth, and composition of lipids were characterized. H. sp. DN1 was found to grow at temperatures approaching freezing to accumulate large intracellular stores of lipids. H. sp. DN1 produces the highest quantity of lipids when grown undisturbed with high light in low temperatures_. Of particular interest was the accumulation of eicosapentaenoic acid, known to be important for human nutrition, and palmitoleic acid, known to improve biodiesel feedstock properties. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:853–861, 2013