Halotolerant Species Research Articles

Resistance of the oil-oxidizing microorganism Dietzia sp. to hyperosmotic shock in reconstituted biofilms

A number of halotolerant and halophilic bacterial strains were isolated from the Romashkinskoe oil field (Tatarstan) stratal waters having a salinity of up to 100 g/l. The isolation of pure cultures involved biofilm reconstitution on M9 medium with paraffins. The associations obtained were dispersed and reinoculated onto solid media that contained either peptone and yeast extract (PY) or paraffins. It was shown that such associations included both oil-oxidizing bacteria and accompanying chemoheterotrophic bacteria incapable of oil oxidation. The pure cultures that were isolated were used for creating binary biofilms. In these biofilms, interactions between halophilic and nonhalophilic bacteria under hypo- and hyperosmotic shocks were investigated. We conducted a detailed study of a biofilm obtained from an oil-oxidizing halotolerant species (with an upper growth limit of 10-12% NaCl) identified as Dietzia sp. and an extremely halophilic gram-negative bacterium (growing within the 5-20% NaCl concentration range) of the genus Chromohalobacter that did not oxidize paraffins. If these microorganisms were grown in a mixed suspension (planktonic) culture that was not supplemented with an additional amount of NaCl, no viable cells of the halophilic microorganism were detected after reinoculation. In contrast, only halophilic cells were detected at a NaCl concentration of 15%. Thus, no mutual protective influence of the microorganisms manifested itself in suspension culture, either under hypo- or under hyperosmotic shock. Neither could the halophile cells be detected after reinoculating a biofilm obtained on a peptone medium without addition of NaCl. However, biofilms produced at a NaCl concentration of 15% contained approximately equal numbers of cells of the halophilic and halotolerant organisms. Thus, the halophile in biofilms sustaining a hyperosmotic shock exerts a protective influence on the halotolerant microorganism. Preliminary data suggest that this effect is due to release by the halophile of osmoprotective substances (ectoine and glutamate), which are taken up by the halotolerant species. Such substances are diluted by a large medium volume in suspension cultures, whereas, in biofilms, their diffusion into the medium is apparently hampered by their interaction with the intercellular polymer matrix.

Succession of late Pleistocene and Holocene ostracode assemblages in a transgressive environment: A study at a coastal locality of the southern Baltic Sea (Germany)

The present study documents the hydrological and coastal evolution of a southern Baltic Sea lagoon by analyzing ostracode associations. Six ostracode zones were distinguished from a 13.5 m long vibro-core in the Pudagla Lowland (NE Germany) using SPLITINF (binary divisive clustering) zonation. Sediments of a Pleistocene freshwater stage are overlain by deposits of a Preboreal brackish water environment, which are not related directly to the development of the Baltic Sea. Different boreal freshwater habitats developed in the study area until marine water protruded the Pudagla site in the course of the Littorina Transgression. A gradual succession in the species assemblage reflects the subsequent transgression. Freshwater species (i.e., Metacypris cordata, Fabaeformiscandona protzi, and Herpetocypris sp.) are substituted in pre-Littorina inland waters (ca. 7.2 14C ka BP) by halotolerant species (i.e., Candona angulata, Sarscypridopsis aculeata, and Plesiocypridopsis newtoni; ca. 6.5 14C ka BP) and finally, the ostracode fauna is dominated by Cyprideis torosa associated with Cytheromorpha fuscata and Loxoconcha elliptica when brackish–marine water conditions are established (ca. 6.4 14C ka BP).

Novel 3′-phosphoadenosine-5′-phosphatases from extremely halotolerant Hortaea werneckii reveal insight into molecular determinants of salt tolerance of black yeasts

The 3′-phosphoadenosine-5′-phosphatase encoded by HAL2 gene, is a ubiquitous enzyme required for the removal of the cytotoxic 3′-phosphoadenosine-5′-phosphate produced during sulfur assimilation in eukaryotes. Salt toxicity in yeast and plants results from Hal2 inhibition by sodium or lithium ions. Two novel HAL2-like genes, HwHAL2A and HwHAL2B, have been cloned from saltern-inhabited extremely halotolerant black yeast Hortaea werneckii. Expression of both HwHAL2 isoforms was differentially inducible upon salt. When the HwHAL2 genes were transferred from such a halotolerant species into the salt sensitive Saccharomyces cerevisiae, the resulting organism can tolerate 1.8 M NaCl or 0.8 M LiCl, the highest reported salt concentrations at which S. cerevisiae can grow. With genetic and biochemical validation we demonstrated the critical HwHal2B sequence motif—the META sequence—common only to Dothideales fungi, with evident effect on the HwHal2B-dependent salt tolerance. These results may have significance for biosaline agriculture in coastal environments.

Bacillus okhensis sp. nov., a halotolerant and alkalitolerant bacterium from an Indian saltpan

A strictly aerobic, rod-shaped bacterium (0.6-0.8 x2-3 microm), designated strain Kh10-101T, was isolated from a saltpan (22 degrees 15' N, 69 degrees 1' E) in the vicinity of Port Okha, India. The creamish pigmented colonies of strain Kh10-101T were round, flat and translucent with irregular margins and a smooth surface. The strain possessed up to three subpolar flagella, and was motile by a corkscrew motion. The strain grew optimally at 37 degrees C (temperature growth range 25-40 degrees C) in a complex glucose-containing medium with 5 % NaCl (NaCl growth range 0-10 %) at pH 9 (pH growth range pH 7-10), indicating that it was a mesophilic halotolerant alkaliphile. The strain was sensitive to lincomycin, meticillin, cefuroxime and cephalexin, but resistant to gentamicin, tetracycline and cotrimazine. Spores were not detected and cells were heat sensitive. The isolate metabolized a range of carbohydrates and hydrolysed casein, gelatin and starch. Growth was not observed on aromatic compounds, Tween 40 or Tween 80. Nitrate was not reduced and catalase was produced. Electron microscopic examination of thin sections revealed a single thick Gram-positive cell wall. The DNA G+C content was 41+/-1 mol%. Phylogenetic analyses of the 16S rRNA gene sequence revealed that strain Kh10-101T was a member of the sixth rRNA group of the genus Bacillus, which includes alkalitolerant, alkaliphilic and halotolerant species. The halotolerant obligate alkaliphile Bacillus krulwichiae is the closest relative of strain Kh10-101T (96 % similarity) but a number of phenotypic differences suggest that strain Kh10-101T (=JCM 13040T=ATCC BAA-1137T) should be designated the type strain of a new species, for which the name Bacillus okhensis sp. nov. is proposed.

The halotolerant fungus Glomerobolus gelineus is a member of the Ostropales

Glomerobolus gelineus is a halotolerant species with a unique method of ballistic propagation. The absence of both sexual and asexual spores made reliable placement of this species, based on morphology alone, within the current fungal classification problematical. A phylogenetic analysis of the large and small nuclear ribosomal subunit and the second largest subunit of RNA polymerase II placed this fungus within the Ostropales, an order comprising lichenized and saprobic species, with good statistical support. Subsequently, a more detailed analysis that combined the nuc LSU rDNA and the mt SSU rDNA confirmed a close relationship to the Stictidaceae. The phylogenetic placement of G. gelineus is also supported by morphological characters. We postulate that the hyphoma lobes of Glomerobolus correspond to the periphysoidal layer in the apothecium of Stictis, and the propagule to the hymenium. Moreover, the presence of crystals in the outer lobes of G. gelineus is another indication of its relationship with Ostropales, which have characteristic crystalliferous hyphae. The placement of Glomerobolus within the Ostropales further expands the ecological diversity exhibited by this order. It also provides a phylogenetic hypothesis for assessing the homology of the enigmatic hyphomal morphology with apothecia-forming Ascomycota.

Relationships between Carex hordeistichos Vill. and halophilic plant communities in Lorraine (France)

Carex hordeistichos, which is a rare species all over its peri-Mediterranean range of distribution, has often been considered as a halophilic plant. A study, carried out in the area of Lorraine where salt marshes are present, showed that this species mostly occurs in non-halophilous habitats. It could only be found in two places in weakly halophilic communities at the border of salt marshes. A bibliographical survey showed that the same situation occurs in all European areas where this rare species has been discovered. Thus it appears that Carex hordeistichos can not be regarded as a halophilic plant, but only as a slightly halo-tolerant species. Conservation plans for this threatened species have to take this edaphical feature into account.

Influence of salinity on seasonal germination of resting stages and composition of microplankton on the Swedish west coast

Surface sediment from Gullmar Fjord, Sweden was cultured in the laboratory to assess the influence of different salinities on the germination of benthic resting stages and subsequent veg- etative growth. Sediment cultures were grown in media with salinities of 15, 25, and 35‰ in both spring and summer conditions. Many microplankton species grew in the cultures. Dominant taxa were the diatoms Chaetoceros, Detonula, Skeletonema, and Thalassiosira, and the dinoflagellates Diplopsalis, Scrippsiella, and Oblea. Growth of T. minima and T. pseudonana after more than 2 yr of storage provides new evidence of a dormant stage in these species. Salinity significantly influenced germination only in D. confervacea and O. rotunda, but it showed significant effects on growth for all the dominant taxa. Salinity optima of the microplankton in the experiments were compared to salin- ity ranges of these species in fjords on the Swedish west coast. In the fjords, D. confervacea grows poorly at salinities >27‰ and may be outcompeted by halotolerant species, such as C. socialis and T. minima. Because salinity is most variable in spring, a wide salinity tolerance is particularly advanta- geous during this season. The dominant dinoflagellates were well adapted to salinities between 22 and 35‰, and O. rotunda is favored at the high end of this range. Results illustrate how climate- related changes in sea-surface salinity may alter the microplankton community on the Swedish west coast through direct effects on resting-stage germination and planktonic growth.

EFFECT OF DIFFERENT CHEMICAL COMPOUNDS ON THE GROWTH OF TWO SOIL ALGAL SPECIES NOSTOC HUMIFUSUM AND OSCILLATORIA EARLEI.

The current study was performed on a farm land at El-Khanka District, Kalyoubia Governorate where the land showed symptoms of increase in its salt content. Some of the physical and chemical characteristics of the collected soil samples were determined. Only two halotolerant species of algae were isolated from the soil samples containing lower total soluble salt contents. Purification of algae from bacteria was done then subjected to a series of experiments for determination of the effect of different chemical constituents on their growth. The results showed that the change in salinity (NaCl contents) as well as changing in carbon and nitrogen sources may have a considerable effect on the growth of the two algae species. In addition, also the major biochemical contents of the algal species were affected by the previous changes.

First survey of fungi in hypersaline soil and water of Mono Lake area (California)

Mono Lake is a closed lake located in central California, east of the Sierra Nevada mountains. It contains dissolved carbonates, sulfates and chlorides at high concentrations. Due to its high salinity, Mono Lake was sometimes compared to the Dead Sea. However, it appears that Mono Lake water and vicinity abound with life. In this work, the fungal flora living in this extreme ecosystem was studied for the first time. Soil, tufa, water and sediment samples were also analyzed for their mineral and salt composition. Results showed that water was particularly rich in sodium, potassium, phosphorus and boron. Soil and sediments contained very high levels of calcium and magnesium, but also barium, boron and strontium. Sodium, phosphorus and iron levels varied in a large extent from one to another sample. Neutral to very alkaline pH were recorded. Water samples were found sterile in the conditions chosen for fungi isolation, while sediment, soil and tufa samples led to the isolation of a total of 67 fungal species (from 23 samples), belonging to various taxonomic groups. From our results no clear effects of the chemical parameters of the samples were observed on fungal life apart from the pH. The methods chosen did not allow the isolation of extremely halotolerant species. We isolated in this work a series of ubiquitous species, suggesting that a selection of resistant and/or adaptable strains of some common species could have occurred. Depending on the medium and the temperature of isolation, it can be hypothesized that some species were present as dormant structures, while some others, isolated at pH 8 on a medium enriched in Na and Ca, could be in a growing form adapted to alkaline and saline conditions. This work contributes to a better knowledge of the mycobiota present in the Mono Lake's ecosystem.

Fungi on Juncus roemerianus 14. Three New Coelomycetes, including Floricola, anam.-gen. nov.

Floricola striata anam.-gen. et sp. nov. is described from senescent inflorescences, culms and leaves, Septoriella unigalerita anam.-sp. nov. and Stagonospora abundata anam.-sp. nov. from senescent standing leaves of Juncus roemerianus at the U. S. east coast. Floricola striata and Stagonospora abundata are facultative marine species from the base and middle of the plant, whereas Septoriella unigalerita can be classified as a terrestrial, but halotolerant species, growing in the middle and tip of the leaves.

A new halotolerant species of Physalacria from Hong Kong

Physalacria maipoensis (Basidiomycetes, Agaricales, Tricholomataceae) is described as a new halotolerant species from a mangrove forest in Hong Kong. A description, illustrations and comparison with phenetically similar taxa are provided.

Spider biodiversity potential of an ungrazed and a grazed inland salt meadow in the National Park 'Neusiedler See-Seewinkel' (Austria): implications for management (Arachnida: Araneae)

To assess the biodiversity potential of an ungrazed and a grazed inland salt meadow in the Seewinkel (Eastern Austria), spider assemblages were recorded by pitfall trapping for 1 year. Both species assemblages consisted, to a large extent, of rare species of conservation interest. The species assemblage of the grazed site was dominated by Pardosa agrestis, but highly specific halotopobiontic species also occurred in higher numbers. Halotolerant species were also present in the ungrazed meadow, but their individual number was much lower. The species composition of this site reflects the more balanced microclimatical situation of the high sward. Comparison of the two assemblages with 207 other meadow spider assemblages of Central Europe shows a separated position, especially of the grazed site assemblage. High similarities with assemblages of meadows with a similar vegetation structure indicate a high importance of management. Considering the high proportion of rare species on both sites, the best management of the salt meadow and pan shores of the Seewinkel should combine areas of light grazing with ungrazed areas. However, the proportion of these parts and the intensity of grazing still remains to be determined by quantitative experiments.

The lichen flora and habitats of the syowa region, continental antarctica

The lichen flora and habitats in the Syowa region of continental Antarctica were surveyed. The distribution patterns of lichens appear to reflect habitat salinity, derived from wind-blown sea spray. Some halotolerant species are established in saline habitats where snow dunes are well developed. Snow and ice ameliorate the salinity of the habitat and provide a major source of moisture for lichens. Wind-borne drift snow carried by katabatic winds or occasional snow showers also provide the source of moisture to lichens growing on dry rock habitats in the Syowa region.

Mycoflora of Soil Around the Dead Sea II - Deuteromycetes (except Aspergillus and Penicillium)

Summary Samples were taken from the top 10 centimeters of soils from 56 localities along the Dead Sea valley. There were 269 isolates representing 106 species dispatched into 51 genera of Deuteromycetes ( Aspergilius and Pesricillium not included) in addition to 20 sterile mycelia and an unidentified black yeast. The genera Alternaria, Ulocladium and Fusarium were represented respectively by 6, 8 and 10 different species and were the most frequently isolated in the different samples. The most common species were Acremonium strictum, Alternaria alternata, A. chlamydospora, Botryotrichum piluliferum, Botrytis cinerea, Cladosporium cladosporioides, Epicoccum nigrum, Fusarium oxysporum, Ulocladium atrum, U. chlamydosporum, U. consortiale . One new Bipolaris species was isolated, which has been the object of two other papers (submitted for publication). One thermophile was found: Scytalidium thermophilum . No strict halophiles but only halotolerant species were obtained. As already noticed in the first part of this work, there does not seem to be a fungus flora that is characteristic of desert soil or highly saline soil. Some ubiquitous soil fungi seem to be able to adapt to these extreme conditions.

The lichen flora and habitats of the Syowa region, continental Antarctica

The lichen flora and habitats in the Syowa region of continental Antarctica were surveyed. The distribution patterns of lichens appear to reflect habitat salinity, derived from wind-blown sea spray. Some halotolerant species are established in saline habitats where snow dunes are well developed. Snow and ice ameliorate the salinity of the habitat and provide a major source of moisture for lichens. Wind-borne drift snow carried by katabatic winds or occasional snow showers also provide the source of moisture to lichens growing on dry rock habitats in the Syowa region.

Seasonal zooplankton fauna of salt evaporation basins in South Australia

Salt evaporation basins are important as disposal sites for saline drainage water and groundwater in heavily irrigated areas in Australia and California. Relatively little is known about the zooplankton species composition of such basins. In this study, three evaporation basins in South Australia (Stockyard Plains, Berri and Noora) were sampled seasonally for zooplankton in 1992. Salinities in the basins ranged from 5 to 30 g L-1. The zooplankton comprised species from inland saline lakes together with some halotolerant species from the River Murray. Notably, several species typical of saline lakes in the region were absent. The zooplankton fauna in all three basins was dominated by microcrustaceans.

The response of the picoplanktonic marine cyanobacterium Synechococcus species WH7803 to phosphate starvation involves a protein homologous to the periplasmic phosphate‐binding protein of Escherichia coli

During phosphate-limited growth the marine phycoerythrin-containing picoplanktonic cyanobacterium Synechococcus sp. WH7803 synthesizes novel polypeptides, including two abundant species of 100 kDa and 32 kDa. The 32 kDa polypeptide was localized to the cell wall, although in a related strain, Synechococcus sp. WH8103, it could be detected in both the cell wall fraction and the periplasm. The gene (designated pstS) encoding this polypeptide was cloned and shown to be present in a single copy. The deduced amino acid sequence indicated a polypeptide consisting of 326 amino acids with a calculated M(r) of 33,763. Comparison of this sequence with that obtained by microsequencing the N-terminus of the 32 kDa polypeptide showed that the mature protein was synthesized as a precursor, the first 24 amino acid residues being cleaved between two alanine residues at positions 24 and 25. The amino acid sequence of the mature polypeptide showed 35% identity and 52% similarity to the periplasmic phosphate-binding protein (PstS) from Escherichia coli, including three regions of much stronger homology which, by comparison with E. coli PstS, are directly involved in phosphate binding. Northern blot analysis revealed a pstS transcript of 1.2 kb in RNA extracted from cells grown in Pi-replete conditions and one of 1.4 kb in considerably increased abundance under Pi-depleted conditions. Homologues of the pstS gene were detected in other marine phycoerythrin-containing Synechococcus strains, but not in freshwater or halotolerant species.

Rediversion Salinity Change in the Cooper River, South Carolina: Ecological Implications

A 70% reduction in freshwater discharge through the Cooper River Basin, South Carolina, has provided a unique opportunity to study changes in estuarine plant communities in response to a system-wide increase in salinity. A one-dimensional tidal prism mixing model was used to simulate the changes in the longitudinal salinity distribution which have occurred in the Cooper River since a diversion in 1985 reduced the mean flow from 442 to 130 m3 s-I. Model simulations indicate that a salinity increase of 10-149100 has occurred in the region of the river where the marsh plant community shifts from a virtual monoculture of Spartina alternQora to a more diverse brackish community. The flow reduction and associated salinity increase are expected to result in an increased dominance of the halophyte, S. alternijlora, and a progressive exclusion of the less halotolerant species which currently inhabit this region.

Further studies on Nephroselmis and its allies (Prasinophyceae). I. The question of the genus Bipedinomonas

Based on a series of collections made in New Zealand it is concluded that Nephroselmis longifilis and Bipedinomonas pyriformis are identical species, for which the correct name is Nephroselmis pyriformis (N. Carter) comb. nov. A detailed examination by light and electron microscopy is given, using material from geographically widely separated areas, including Greenland, the North Sea, a shallow Danish Fiord, Thailand and New Zealand. N. pyriformis is a temperature– and halotolerant species, as shown by its known range of occurrence at temperatures from 2.3°C (West Greenland) to ca. 28°C (Thailand) and at salinities between 3 and 36%o. Features of fine structural interest include details of the scaly covering on the flagellar and cell surfaces, the former very similar to those on the flagella of Tetraselmis cordiformis, a quadriflagellate prasinophyte. Within the cell, the pyrenoid shows an unusual fine structure, being penetrated by a number of membrane–lined pockets, in which the membranes are continuous with thylakoids. N. pyriformis is compared with other members of the genus, and a list of the few known species is included.

The immigration of spiders (Araneida) into a new polder

Abstract. (1) The immigration of spiders into the Lauwerszeepolder (constructed in 1969) was studied during four years in four areas. The spider fauna was sampled weekly and 65 000 specimens of eighty‐four species were caught using strip traps, window traps, simple pitfall traps and fences.(2) About sixty species from all kinds of habitats were caught rarely; nineteen species were caught in numbers that suggest that they had established populations in the study areas.(3) The four successful pioneer species, plus two marsh‐dwelling species, were most abundant during 1969 and 1970. The 1971 catch was dominated by species from saline habitats; they became less abundant in 1972 when species from non‐saline habitats increased. Only halotolerant species established populations.(4) No evidence was found that dispersing spiders select certain areas. The differences between the spider fauna of the differennt study areas arise from degrees of success in colonization by immigrants. Pioneer species are least influenced by the abiotic environment.(5) A greater aeronautic dispersal power is found in species inhabiting unstable habitats than in species from stable habitats.(6) Aeronautic activity in adult linyphiids (s.l.) is not restricted to a special season, but is related to definite phases of the phenology.(7) Male and female erigonids are equally active in aeronautic behaviour. In erigonids and linyphiids intense aeronautic activity coincides with great ground activity; on the ground males are more active than females.