Cloning vectors for Streptococcus thermophilus derived from a native plasmid

Marine sponges frequently contain a complex mixture of bacteria, fungi, unicellular algae and cyanobacteria. Epifluorescent microscopy showed that Mycale (Carmia) hentscheli contained coccoid cyanobacteria. The 16S rRNA gene was amplified, fragments cloned and analysed using amplified rRNA gene restriction analysis. The nearly complete 16S rRNA gene of distinct clones was sequenced and aligned using ARB. The phylogenetic analysis indicated the presence of four closely related clones which have a high (8%) sequence divergence from known cyanobacteria, Cyanobacterium stanieri being the closest, followed by Prochloron sp. and Synechocystis sp. All belong to the order Chroococcales. The lack of non-molecular evidence prevents us from proposing a new genus.     

Methanosarcina mazei LYC, a New Methanogenic Isolate Which Produces a Disaggregating Enzyme

A methanogenic coccoid organism, Methanosarcina mazei LYC, was isolated from alkaline sediment obtained from an oil exploration drilling site. The isolate resembled M. mazei S-6 by exhibiting different morphophases during its normal growth cycle. It differed from M. mazei S-6 by undergoint a spontaneous shift from large, irregular aggregates of cells to small, individual, irregular, coccoid units. In batch cultures at pH 7.0, M. mazei LYC grew as aggregates during the early growth stage. As the batch culture began exponential growth, the cell aggregates spontaneously dispersed: the culture liquid became turbid, and myriads of tiny (diameter, 1 to 3 μm) coccoid units were observed under phase-contrast microscopy. Disaggregation apparently was accomplished by the production of an enzyme which hydrolyzed the heteropolysaccharide component of the cell wall; the enzyme was active on other Methanosarcina strains as well. Although the enzyme was active when tested at pH 6.0, it apparently was not produced at that pH: when strain LYC was grown at pH 6.0, only cell aggregates were present throughout batch growth. Individual coccoid cells of M. mazei LYC were sensitive to sodium dodecyl sulfate, but the large aggregates of cells were not. Strain LYC rapidly used H₂-CO₂, in addition to methanol, and mono-, di-, and trimethylamine as methanogenic substrates; acetate was used very slowly. Its optimum growth temperature was 40°C, and its optimum pH was 7.2.     

Phototrophic Biofilms on Ancient Mayan Buildings in Yucatan, Mexico

Buildings at the important archaeological sites of Uxmal and Kabah, Mexico, are being degraded by microbial biofilms. Phospholipid fatty acid (PLFA) and chlorophyll a analyses indicated that phototrophs were the major epilithic microorganisms and were more prevalent on interior walls than exterior walls. Culture and microscopical techniques showed that Xenococcus formed the major biomass on interior surfaces, but the stone-degrading genera Gloeocapsa and Synechocystis were also present in high numbers. Relatively few filamentous algae and cyanobacteria were detected. The fatty acid analysis also showed that complex biofilms colonize these buildings. Circular depressions observed by scanning electron microscopy (SEM) on stone and stucco surfaces beneath the biofilm corresponded in shape and size to coccoid cyanobacteria. SEM images also demonstrated the presence of calcareous deposits on some coccoid cells in the biofilm. Phototrophic biofilms may contribute to biodegradation by (1) providing nutrients that support growth of acid-producing fungi and bacteria and (2) active “boring” behavior, the solubilized calcium being reprecipitated as calcium carbonate. Received: 15 March 1999 / Accepted: 24 June 1999     

Changes of phytoplankton communities in Lakes Naivasha and Oloidien, examples of degradation and salinization of lakes in the Kenyan Rift Valley

Increasing degradation of the water quality, caused by overuse and salinization, leads to considerable changes of the phytoplankton composition in Kenyan Rift Valley lakes. Exemplarily, the phytoplankton communities and biomasses of deteriorating freshwater Lake Naivasha and salinizing Lake Oloidien were studied between 2001 and 2005, accompanied by physico-chemical measurements (pH, total phosphorus and nitrogen, alkalinity, conductivity). Over the last three decades, the ecology of these two water basins has been subjected to dramatic changes, caused by excessive use of water and catchment area by man. In L. Naivasha a shift in the dominance of coccoid cyanobacteria towards dominance of Chlorophyceae (Botryococcus terribilis) was observed. Lake Oloidien exhibited a shift in the dominance of coccoid Chlorophyceae towards dominance of cyanobacteria (Arthrospira fusiformis, Anabaenopsis elenkinii). Phytoplankton findings and chemical data demonstrate that L. Naivasha has developed towards a eutrophic freshwater lake while L. Oloidien has progressed towards a hypereutrophic alkaline-saline lake. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: J. Padisak     

Control of the Life Cycle of Methanosarcina mazei S-6 by Manipulation of Growth Conditions

The morphology of Methanosarcina mazei was controlled by magnesium, calcium, and substrate concentrations and by inoculum size; these factors allowed manipulation of the morphology and interconversions between pseudosarcinal aggregates and individual, coccoid cells. M. mazei grew as aggregates in medium with a low concentration of catabolic substrate (either 50 mM acetate, 50 mM methanol, or 10 mM trimethylamine) unless Ca²⁺ and Mg²⁺ concentrations were high. Growth in medium high in Ca²⁺, Mg²⁺, and substrate (i.e., 150 mM acetate, 150 mM methanol, or 40 mM trimethylamine) converted pseudosarcinal aggregates to individual cocci. In such media, aggregates separated into individual cells which continued to grow exclusively as single cells during subsequent transfers. Conversion of single cells back to aggregates was complicated, because conditions which supported the aggregated morphology (e.g., low calcium or magnesium concentration) caused lysis of coccoid inocula. We recovered aggregates from coccoid cells by inoculating serial dilutions into medium high in calcium and magnesium. Cells from very dilute inocula grew into aggregates which disaggregated on continued incubation. However, timely transfer of the aggregates to medium low in calcium, magnesium, and catabolic substrates allowed continued growth as aggregates. We demonstrated the activity of the enzyme (disaggregatase) which caused the dispersion of aggregates into individual cells; disaggregatase was produced not only during disaggregation but also in growing cultures of single cells. Uronic acids, the monomeric constituents of the Methanosarcina matrix, were also produced during disaggregation and during growth as coccoids.     

The most ancient terrestrial lichen <Emphasis Type="Italic">Winfrenatia reticulata</Emphasis>: A new find and new interpretation

Silicified fossils from Rhynie cherts in Scotland are studied. A lichen belonging to the genus Winfrenatia is detected and studied. This oldest terrestrial lichen is dated to the Pragian (=Siegenian) of the Early Devonian. New characters of the lichen are described, and their new interpretation is given. The main component of the lichen thallus is a filamentous cyanobacterium (Nostocales). Structures which were interpreted as fungal hyphae are probably hollow sheaths of this cyanobacterium. Mycobiont hyphae develop at the base of the thallus and symbiose with a coccoid cyanobacterium. Thus, Winfrenatia reticulata is a three-parted organism, constituted of a mycobiont and filamentous and coccoid cyanobacteria.     

Ultrastructural and microspectrophotometric characterization of multiple species of cyanobacterial photosymbionts coexisting in the colonial ascidian Trididemnum clinides (Tunicata,Ascidiacea, Didemnidae)

Trididemnum clinides is a multi-photosymbiotic ascidian that inhabits shallow coral reef lagoons. Three types of cyanobacteria are harboured in the tunic of the ascidian colony; of these, two are unicellular coccoid cyanobacteria and the other is a multicellular filamentous type. They also differ in ultrastructure and distribution patterns within the host tunic. Microspectrophotometric analysis revealed the composition of photosynthetic pigments in each photosymbiont. One of the coccoid types is yellowish-green and is distributed under the colony surface. This photosymbiont cell preferentially absorbs red and blue light, and therefore the dominant colour in the inner tunic is green. The other two types of coexisting photosymbionts contain the green-light-absorbing R-phycoerythrin as the major photosynthetic pigment; they exploit the wavelengths of light not used by the first type of photosymbiont. In T. clinides, the outer and inner photosymbionts in the tunic have different photosynthetic pigments, which adapt to each microhabitat, thereby sharing the incident light resources effectively.     

Characteristics and role of the exocellular polysaccharides produced by five cyanobacteria isolated from phototrophic biofilms growing on stone monuments

Three coccoid and two filamentous cyanobacterial strains were isolated from phototrophic biofilms exposed to intense solar radiation on lithic surfaces of the Parasurameswar Temple and Khandagiri caves, located in Orissa State, India. Based on to their morphological features, the three coccoid strains were assigned to the genera Gloeocapsosis and Gloeocapsa, while the two filamentous strains were assigned to the genera Leptolyngbya and Plectonema. Eleven to 12 neutral and acidic sugars were detected in the slime secreted by the five strains. The secretions showed a high affinity for bivalent metal cations, suggesting their ability to actively contribute to weakening the mineral substrata. The secretion of protective pigments in the polysaccharide layers, namely mycosporine amino acid-like substances (MAAs) and scytonemins, under exposure to UV radiation showed how the acclimation response contributes to the persistence of cyanobacteria on exposed lithoid surfaces in tropical areas.     

Bioactive polar lipids from Chroococcidiopsis sp. (Cyanobacteria)

Many studies indicate that various bioactive metabolites subsist in cyanobacteria. Glycolipids of cyanobacteria are reported as molecules that exert specific bioactivities. In this study, total lipids of Chroococcidiopsissp., a coccoid cyanobacterium isolated from a Greek cave, were separated into neutral and polar-lipids and the latter were further fractionated by high-performance liquid chromatography (HPLC). Each polar lipid fraction was tested in vitro for its ability to inhibit platelet-activating factor (PAF)- and thrombin-induced washed rabbit platelet aggregation and/or to cause platelet aggregation. The structures of the most active fractions were elucidated by biological assays and identified by electrospray mass spectrometry. One fraction was a potent inhibitor of PAF-induced platelet aggregation. Structural studies of this fraction indicated the existence of phospho-glyco analog of ceramide. Another fraction that was a potent inhibitor of PAF- as well as of thrombin-induced platelet aggregation was structurally elucidated as a phospho-acetylated glyco-analog of diglyceride. The fraction that induced platelet aggregation was identified as a phospho-acetylated-glyco analog of ceramide. These novel bioactive polar lipids in cyanobacteria in regard to the structure and biological activity may contribute to the allergic character of cyanobacteria.     

Lithic cyanobacterial communities in the polyextreme Sahara Desert: implications for the search for the limits of life

The hyperarid Sahara Desert presents extreme and persistent dry conditions with a limited number of hours during which the moisture availability, temperature and light allow phototrophic growth. Some cyanobacteria can live in these hostile conditions by seeking refuge under (hypolithic) or inside (endolithic) rocks, by colonizing porous spaces (cryptoendoliths) or fissures in stones (chasmoendoliths). Chroococcidiopsis spp. have been reported as the dominant or even the only phototrophs in these hot desert lithic communities. However, the results of this study reveal the high diversity of and variability in cyanobacteria among the sampled habitats in the Sahara Desert. The chasmoendolithic samples presented high coccoid cyanobacteria abundances, although the dominant cyanobacteria were distinct among different locations. A high predominance of a newly described cyanobacterium, Pseudoacaryochloris sahariense, was found in hard, compact, and more opaque stones with cryptoendolithic colonization. On the other hand, the hypolithic samples were dominated by filamentous, non-heterocystous cyanobacteria. Thermophysiological bioassays confirmed desiccation and extreme temperature tolerance as drivers in the cyanobacterial community composition of these lithic niches. The results of the present study provide key factors for understanding life strategies under polyextreme environmental conditions. The isolated strains, especially the newly described cyanobacterium P. sahariense, might represent suitable microorganisms in astrobiology studies aimed at investigating the limits of life.     

Nitrogen fixation andnif gene organization in branched heterocystous cyanobacteria: Variation in the presence ofxisA

Five branched heterocystous cyanobacteria (Scytonematopsis sp.,Scytonema sp.,Tolypothrix ceylonica, Mastigocladus sp. andFischerella sp.) were examined for their pattern of induction of nitrogenase activity andnif gene organization. All the forms showed the onset of nitrogenase activity after 12 h which could be correlated with the appearance of proheterocysts. The highest activity was exhibited byT. ceylonica. Hybridization studies revealed the presence of thenifD gene but the absence of thexisA gene inMastigocladus sp. andScytonematopsis sp. Interestingly,Tolypothrix sp. andScytonema sp. DNA samples hybridized withxisA. Hence no uniformity seems to exist regarding the presence ofxisA and the relatednif gene organization in branched heterocystous cyanobacteria. This investigation throws light on the primitive character and phylogenetic relatedness of branched forms to the coccoid/colonial forms. It also provides evidence for the proposition that stigonematacean cyanobacteria may not represent the most advanced cyanobacterial forms; rather they may link the coccoid and filamentous forms.     

Picoplankton dynamics in Davies Reef lagoon, the Great Barrier Reef, Australia

The diel variations in abundance and frequency of dividing cells(FDC) of coccoid cyanobacteria in a coral reef lagoon were investigatedin June, September and December 1989, and April 1990. Cyanobacteriaand picoplanktonic eukaryotes (<3 µm) were sampledmonthly from January to December 1990. The average abundancesof cyanobacteria and eukaryotes ranged between 1.17–10.0610⁴cells ml^–1 and 0.16–2.4110⁴ cells ml^–1, respectively,with abundances of both being higher in summer (November-April)than in winter (May-October). The ratio of cyanobacteria toeukaryotes fluctuated from 1.93 to 8.67, independent of theseasonal variation in their abundances. The instantaneous growthrate of cyanobacteria, which was estimated from the daytimeabundance increment, ranged between 0.430 and 3.144 day^–1The estimated daily specific growth rate of cyanobacteria bythe FDC method ranged between 0.231 and 0.966 day^–1. InApril, despite the high specific growth rate and low flushingconditions. cyanobacterial abundance showed a cyclic diel pattern,suggesting a strong grazing impact on their population.     

Characteristics and role of the exocellular polysaccharides produced by five cyanobacteria isolated from phototrophic biofilms growing on stone monuments

Three coccoid and two filamentous cyanobacterial strains were isolated from phototrophic biofilms exposed to intense solar radiation on lithic surfaces of the Parasurameswar Temple and Khandagiri caves, located in Orissa State, India. Based on to their morphological features, the three coccoid strains were assigned to the genera Gloeocapsosis and Gloeocapsa, while the two filamentous strains were assigned to the genera Leptolyngbya and Plectonema. Eleven to 12 neutral and acidic sugars were detected in the slime secreted by the five strains. The secretions showed a high affinity for bivalent metal cations, suggesting their ability to actively contribute to weakening the mineral substrata. The secretion of protective pigments in the polysaccharide layers, namely mycosporine amino acid-like substances (MAAs) and scytonemins, under exposure to UV radiation showed how the acclimation response contributes to the persistence of cyanobacteria on exposed lithoid surfaces in tropical areas.     

Observations on cyanobacterial population collapse in eutrophic lake water

In two laboratory-scale enclosures of water from the shallow, eutrophic Lake Loosdrecht (the Netherlands), the predominating filamentous cyanobacteria grew vigorously for 2 weeks, but then their populations simultaneously collapsed, whereas coccoid cyanobacteria and algae persisted . The collapse coincided with a short peak in the counts of virus-like particles. Transmission electron microscopy showed the morphotype Myoviridae phages, with isometric heads of about 90 nm outer diameter and >100-nm long tails, that occurred free, attached to and emerging from cyanobacterial cells. Also observed were other virus-like particles of various morphology. Similar mass mortality of the filamentous cyanobacteria occurred in later experiments, but not in Lake Loosdrecht. As applies to lakes in general, this lake exhibits high abundance of virus-like particles. The share and dynamics of infectious cyanophages remain to be established, and it is as yet unknown which factors primarily stabilize the host–cyanophage relationship. Observations on shallow, eutrophic lakes elsewhere indicate that the cyanophage control may also fail in natural water bodies exhibiting predominance of filamentous cyanobacteria. Rapid supply of nutrients appeared to be a common history of mass mortality of cyanobacteria and algae in laboratory and outdoor enclosures as well as in highly eutrophic lakes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Stromatoporoid-coral intergrowths in a Silurian biostrome

Four stromatoporoid species from a stromatoporoid biostrome in the middle Ludlow Hemse Beds, Gotland, Sweden, show intergrowths with syringoporid tabulate and rugose corals, and indicate close relationships between particular coral and stromatoporoid species. The stromatoporoid Clathrodictyon convictum always contains ?Syringopora and this tabulate is rarely found in the other stromatoporoids. C. convictum is also closely associated with Tryplasma flexuosum (rugosa) while Petrozium pelagicum (rugosa) occurs only in the stromatoporoids Plectostroma intermedium and Parallelostroma typicum. The microstructure of ?Syringopora within the stromatoporoids is composed of an inner lamellar layer and an outer radial layer of calcite crystals. Diagenetic alteration has affected the microstructure which differs from recently described Devonian forms having only a radial layer. This shows variability in the structure of the tabulates within stromatoporoids. Information is sparse on the range of such variation and assessment of the relative importance of taxonomic, palaeoenvironmental and diagenetic effects is not possible in the present sample. No evidence is found to prove the precise nature of the relationships; they were not parasitic but may have been mutually symbiotic, or (most probably) commensal. The results suggest that the corals selected the most suitable stromatoporoid species for their requirements. Stromatoporoid morphology may have had an important influence on the association, where corals are more abundantly associated with those stromatoporoid species which adopted a high profile. Overall the associations appear to have allowed the corals to explore higher energy habitats otherwise unavailable to their delicate branching structure.     

Polyphasic Detection of Cyanobacteria in Terrestrial Biofilms

Cyanobacterial populations detected on buildings by traditional methods are mainly filamentous, whereas direct microscopy shows that they are principally coccoid morphotypes that often cannot be isolated in culture, but may grow on artificial media when the spatial biofilm relationships are maintained. The polyphasic strategy described here was to select morphologically distinct colonies from rehydrated biofilms for direct DNA amplification, allowing uncultured organisms to be sequenced and their morphology to be characterized by microscopy. DNA data banks currently contain many entries for cyanobacteria of unrecorded morphology, which does not facilitate identification, although genetic variability in a population may be assessed. The sequence homologies of the present biofilm organisms (EMBL accession numbers AJ619681 to 619690) with those in DNA databanks were low, indicating differences between xerophytic cyanobacteria on walls and aquatic species comprising the majority in the databases. Further development of databases for the populations found in this environment, subject to temperature extremes, repeated desiccation and high UV and salt levels, is required.     

Polyphasic detection of cyanobacteria in terrestrial biofilms

Cyanobacterial populations detected on buildings by traditional methods are mainly filamentous, whereas direct microscopy shows that they are principally coccoid morphotypes that often cannot be isolated in culture, but may grow on artificial media when the spatial biofilm relationships are maintained. The polyphasic strategy described here was to select morphologically distinct colonies from rehydrated biofilms for direct DNA amplification, allowing uncultured organisms to be sequenced and their morphology to be characterized by microscopy. DNA data banks currently contain many entries for cyanobacteria of unrecorded morphology, which does not facilitate identification, although genetic variability in a population may be assessed. The sequence homologies of the present biofilm organisms (EMBL accession numbers AJ619681 to 619690) with those in DNA databanks were low, indicating differences between xerophytic cyanobacteria on walls and aquatic species comprising the majority in the databases. Further development of databases for the populations found in this environment, subject to temperature extremes, repeated desiccation and high UV and salt levels, is required.     

氮磷营养盐添加对二甲基巯基丙酸内盐合成与降解细菌及其功能基因的影响

【目的】二甲基巯基丙酸内盐(dimethylsulfoniopropionate,DMSP)是海洋中主要的有机硫化物之一,是海洋细菌硫的主要来源,海洋细菌将其分解成"冷室气体"二甲基硫(dimethylsulfide,DMS),对调节全球气候变化和驱动地球硫循环有重要作用。本研究通过中国东海水体的现场围隔实验模拟海水富营养化对DMSP、DMS产量以及DMSP合成基因(dsyB和mmtN)和降解基因(dddP和dmdA)及相关功能细菌的影响。【方法】通过流式细胞仪计数92个围隔海水样品中微微型浮游生物的数量,采用Illumina MiSeq测序技术对海水样品中细菌的16S rRNA基因进行高通量测序,利用荧光定量PCR技术定量测定16S rRNA基因、DMSP合成及降解基因的丰度。【结果】研究发现,同时添加硝酸盐(6.00μmol/L)和磷酸盐(0.375μmol/L)能促进叶绿素a、DMSP、DMS的浓度上升。对于DMSP合成基因,只加磷酸盐能促进dsyB及Phaeobacter等相应物种的富集,虽然同时添加硝酸盐和磷酸盐使dsyB富集,但相对只加磷酸盐却不利于dsyB积累;同时添加硝酸盐和磷酸盐也抑制Alteromonas的生长,进而抑制了mmtN的富集。对于DMSP降解基因,同时加入硝酸盐和磷酸盐促进了dddP及Thalassococcus、Thalassobius、Loktanella和Shimia等物种的富集,却抑制了SAR11、Sulfitobacter等的富集,从而导致dmdA无法被富集。【结论】氮限制能更好地促进DMSP合成基因的表达,从而迫使细菌增加DMSP的合成以应对氮营养条件不足的生存环境,并进而提高DMSP脱甲基化的比例为细菌提供更多能量;而在硝酸盐和磷酸盐充足情况下,细菌相对减少DMSP的合成且更倾向于裂解DMSP产生DMS来降低硫同化的比例。本研究结果强调了海水富营养化对细菌合成与降解DMSP过程的影响。     

Cyanobacterial Picoplankton from Lake Constance*

Four types of unicellular cyanobacteria were classified by pigment composition and cell size. These originated from the picoplankton fraction of Lake Constance, Germany. β-Carotene and zeaxanthin were found to be the main carotenoids of three Synechococcus isolates. In this group, coccoid forms with phycocyanin-rich phycobilisomes also produce caloxanthin and nostoxanthin, which are xanthophylls with 3 and 4 hydroxy groups, respectively. In addition, these rare carotenoids are observed in rod-forming Synechococcus isolates which contain phycoerythrin-rich phycobilisomes, but they are very low or absent in the coccoid phycoerythrin-rich isolates. Due to size and pigment content the coccoid forms are similar to Synechococcus leopoliensis (SAUG B 1402-1, formerly Anacystis nidulans) and S. rubescens (SAUG B 3.81) while the rod-forming isolates differ from S. elongatus (PCC 6716) in phycobilisome composition. The isolate BO 8402 was tentatively assigned to Synechocystis but differs in pigment composition from all strains described as yet. The green cultures exhibited a faint red glow due to an unusual high in vivo autofluorescence from phycocyanin. Neither were phycobilisomes found in a standard preparation nor was allophycocyanin present. The most abundant carotenoids are β-carotene and caloxanthin, while zeaxanthin, with 12 % of all colored carotenoids, is low. All forms described in this paper lack complementary chromatic adaptation, indicating that the pigment composition is a reliable parameter to identify these freshwater isolates.     

Effects of the inoculation of cyanobacteria on the microstructure and the structural stability of a tropical soil

Cyanobacteria are widespread photosynthetic microorganisms among which some are able to fix atmospheric nitrogen. We investigated the impact of indigenous cyanobacteria strains (Nostoc) inoculation on physical characteristics of poorly aggregated soils from Guquka (Eastern Cape, South Africa). The soil aggregates (3–5 mm) were arranged into a layer of 10–20 mm thick, and sprayed with cyanobacteria solution. Subsequently the inoculated and un-inoculated samples were incubated (30°C, 80% humidity, continuous illumination at 100 μmol m⁻² s⁻¹). Their micromorphological characteristics and aggregate stability were investigated, after 1, 2, 3, 4 and 6 weeks of incubation, by using high resolution Cryo-SEM and aggregate breakdown tests. Micromorphological investigations revealed that the surface of un-inoculated samples remained uncovered, while the inoculated samples were partially covered by cyanobacteria material after one week of incubation. A dense superficial network of cyanobacterial filaments and extracellular polymer secretions (EPS) covered their surface after 4 and 6 weeks of incubation. Organo-mineral aggregates comprising cyanobacterial filaments and EPS were observed after 6 weeks of incubation. The results of aggregate breakdown tests showed no significant difference between un-inoculated samples after 1, 2, 3, 4 or 6 weeks, while they revealed improvement of aggregate stability for inoculated samples. The improvement of aggregate stability appeared in a short while following inoculation and increased gradually with time and cyanobacteria growth. The increase in aggregate stability is likely related to the changes induced in micromorphological characteristics by cyanobacterial filaments and EPS. It reflects the effect of coating, enmeshment, binding and gluing of aggregates and isolated mineral particles by cyanobacteria material. Our study presents new data demonstrating the improvement of soil physical quality in a few weeks after cyanobacteria inoculation. The interaction of the inocula and other biotic components is worthy of study before field application of cyanobacteria.