High Concentrations Of Sodium Chloride Research Articles

Extraction of high-quality genomic DNA from different plant orders applying a modified CTAB-based method

BackgroundReliable measurement of DNA concentration and purity is important for almost all molecular genetics studies. Different plant species have varying levels of polysaccharides, polyphenols, and other secondary metabolites which combine with nucleic acids during DNA isolation and further affect the quality of the extracted DNA. The current extraction protocol is based upon the conventional cetyl trimethylammonium bromide (CTAB) method with further modifications for the extraction of DNA from variable plant seeds and crops belonging to seven different orders. The principle modifications currently employed for DNA extraction involved the use of higher CTAB concentration and higher levels of 2-β-mercaptoethanol. Additionally, higher concentrations of sodium chloride and potassium acetate were added simultaneously with absolute ice cold isopropanol for the precipitation of DNA free from polysaccharides.Results and conclusionThe prescribed modifications in the present method establish a quick and efficient standardized protocol for DNA extraction from different plant orders. The current extraction protocol, therefore, can be of great value for molecular analysis involving large numbers of different plant samples from different orders. These modifications consistently produced pure and high-quality DNA suitable for further molecular analysis. Successful PCR amplification with random amplified polymorphic DNA primer, NPTII gene, and the complete digestion of the isolated DNA with the HindIII restriction enzyme validated the quality of the isolated DNA. Moreover, it reflects the efficiency of the protocol and proves its suitability for further applications for the assessment of food safety, detection of genetically modified (GM) crops, and conservation of biodiversity.

Seed-germination ecology of glyphosate-resistant and glyphosate-susceptible biotypes of Echinochloa colona in Australia

Echinochloa colona L. (Link) (awnless barnyard grass) is one of the top three most problematic weeds of summer crops in Australia. This weed has evolved resistance to glyphosate. A study was conducted to evaluate the effect of environmental factors on the germination and seedling emergence of a glyphosate-resistant (GR) and a glyphosate-susceptible (GS) biotype of E. colona. The two biotypes had similar germination and emergence responses to light and temperature conditions, water stress, solution pH, sorghum residue cover and seed burial depth. Light stimulated germination more than dark conditions, and seeds germinated at a wide range of alternating day/night temperatures, from 20°C/10°C to 35°C/25°C, whereas no seeds germinated at 15°C/5°C. These results suggest that E. colona can emerge in spring, summer and autumn in Queensland. The sodium chloride concentration required to inhibit 50% germination was greater for the GR biotype (209 mm) than the GS biotype (174 mm). Seed germination was not affected by pH in the range 4–10. Water stress reduced germination by 50% at an osmotic potential of –0.44 MPa. In a shade-house study, retention of sorghum residue cover on the soil surface reduced the seedling emergence of E. colona. Emergence was 70% in the absence of crop residue, whereas a residue amount of 8 t ha–1 reduced emergence to 47%. Emergence was greatest for seeds placed on the soil surface and declined linearly with increasing burial depth; no seedlings emerged from 8 cm depth. The GR biotype had higher germination than the GS biotype under high sodium chloride concentrations; therefore, this biotype may be highly competitive with crops under highly saline conditions. Because germination was high on the soil surface and was stimulated by light, this weed will remain problematic under no-till farming systems in Australia.

In Vitro Antioxidant potential of Microbial isolates from Diverse Habitats

Microbial extracts have served as a treasured source of diverse molecules in many drug discovery efforts and led to the discovery of several important drugs. Identification of microbial strains having promising biological activities and purifying the bio-molecules responsible for the activities, have led to the discovery of many bioactive molecules. Extracellular and intracellular extracts of the metabolites of thirty-six bacterial and twenty-four fungal isolates, grown under unusual conditions such as high temperature, high sodium chloride and low glucose concentrations, were in vitro tested for their antioxidant potential by diphenyl picryl hydrazyl (DPPH) radical scavenging method , ABTS [2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging and superoxide radical scavenging by alkaline DMSO nitro blue tetrazolium (NBT) methods. Among the extracellular and intracellular extracts of bacterial and fungal isolates, F-15E showed the maximum antioxidant potential with IC50 of 188.32±0.42 µg/ml by DPPH method. While maximum superoxide radical scavenging ability was shown by F-21E with an IC50 value of 134.01±1.61 µg/ml. In case of ABTS radical scavenging studies, it is interesting to note that the extracellular ethyl acetate extract of F-12 showed an IC50 value of 10.57±0.14 µg/ml, which was better than standard ascorbic acid. Fungal extracts were more effective as antioxidants than bacterial extracts and extracellular fungal metabolites exhibited maximum antioxidant activity than intracellular metabolites.

Phase equilibrium condition measurements in carbon dioxide hydrate forming system coexisting with sodium chloride aqueous solutions

Three phase equilibrium conditions of (sodium chloride aqueous solution + carbon dioxide hydrate + vapour carbon dioxide) were measured to establish seawater desalination technology using clathrate hydrates. The three phase equilibrium condition measurements were performed at temperatures between 271.85 K and 279.05 K, and at pressures between 1.283 MPa and 3.617 MPa. The concentrations of sodium chloride aqueous solution were 0.0350, 0.0700, 0.1000, and 0.1050 in mass fraction. It was found that the equilibrium temperature difference between pure water system and each sodium chloride concentration system at the same pressure was hardly influenced by the pressure level. In addition, it was found that the equilibrium temperature depression of carbon dioxide hydrate by the addition of sodium chloride is smaller than that of ice and cyclopentane hydrate especially at the high concentration of sodium chloride.

Highly Efficient Transfer of 7TM Membrane Protein from Native Membrane to Covalently Circularized Nanodisc

Incorporating membrane proteins into membrane mimicking systems is an essential process for biophysical studies and structure determination. Monodisperse lipid nanodiscs have been found to be a suitable tool, as they provide a near-native lipid bilayer environment. Recently, a covalently circularized nanodisc (cND) assembled with a membrane scaffold protein (MSP) in circular form, instead of conventional linear form, has emerged. Covalently circularized nanodiscs have been shown to have improved stability, however the optimal strategies for the incorporation of membrane proteins, as well as the physicochemical properties of the membrane protein embedded in the cND, have not been studied. Bacteriorhodopsin (bR) is a seven-transmembrane helix (7TM) membrane protein, and it forms a two dimensional crystal consisting of trimeric bR on the purple membrane of halophilic archea. Here it is reported that the bR trimer in its active form can be directly incorporated into a cND from its native purple membrane. Furthermore, the assembly conditions of the native purple membrane nanodisc (PMND) were optimized to achieve homogeneity and high yield using a high sodium chloride concentration. Additionally, the native PMND was demonstrated to have the ability to assemble over a range of different pHs, suggesting flexibility in the preparation conditions. The native PMND was then found to not only preserve the trimeric structure of bR and most of the native lipids in the PM, but also maintained the photocycle function of bR. This suggests a promising potential for assembling a cND with a 7TM membrane protein, extracted directly from its native membrane environment, while preserving the protein conformation and lipid composition.

Salar del Hombre Muerto, source of lithium-tolerant bacteria

The Salar del Hombre Muerto is a flat salt with great microbial activity despite the existing extreme conditions like high altitude, lack of water, low level of oxygen, high radiation and high concentration of sodium and lithium chloride. Despite these unfavorable conditions, we found microbial diversity with the presence of fungi, algae, and bacteria. From aqueous solutions and soil samples, a total of 238 bacteria were isolated and 186 of them were able to grow in the presence of salt. About 30% of the strains showed the ability to grow in solid medium proximally to a LiCl solution close to saturation (636g/L). These isolates were characterized taking into account the morphology, Gram stain, ability to form biofilms and to produce pigments, and mainly according to the tolerance against lithium chloride. Bacillus was predominant among the most tolerant 26 microorganisms found, followed by Micrococcus and Brevibacterium. Members of the genera Kocuria, Curtobacterium and Halomonas were also represented among the bacteria with tolerance to 30 and 60g/L of LiCl in defined liquid medium. All the capacities found in these microorganisms make them extremely interesting for biotechnological applications.

Stress resistance, motility and biofilm formation mediated by a 25kb plasmid pLMSZ08 in Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen that can form biofilm and tolerate severe environment condition and thus persist in food product for a prolonged period, which poses a significant risk to food safety. While some chromosomal genetic determinants associated with stress resistance and biofilm formation have been characterized, plasmid-mediated stress resistance in particular L. monocytogenes strains are less known. In this study, we showed a L. monocytogenes strain SZ08 (serovar 1/2b) isolated from a raw meat processing environment harbored a 25kb plasmid, designated as pLMSZ08. After incubation under the selective condition containing novobiocin, pLMSZ08 was successfully cured from SZ08. Compared to its parental strain SZ08, the cured strain SZ08* was not able to grow well under the high concentration of sodium chloride (5.5%). SZ08* displayed higher efficiency of plaque formation compared with its parental strain SZ08. There were no significant growth difference under different temperature and pH conditions between SZ08 and SZ08*. Biofilm formation of SZ08* reduced significantly compared with SZ08 after 48hr incubation. Furthermore, the relative expression levels of flagella-associated genes in SZ08* were up-regulated comparing to those in SZ08. We have sequenced the pLMSZ08 and the sequencing results showed that pLMSZ08 harbors genes associated with transcriptional regulation, metal/drug transport, histidine kinase and ATPase. These results suggested that these genes encoded by pLMSZ08 are associated with tolerance, motility and biofilm formation in L. monocytogenes SZ08.

Eighteenth- and nineteenth-century salt production in Saltville, Virginia

ABSTRACTThe geology of the Saltville Valley in southwest Virginia creates a brine with an exceptionally high concentration of sodium chloride (98.7%). Because of this resource, the town of Saltville, Virginia, became the major producer of salt for the Confederacy during the latter half of the Civil War. The wood-fired salt furnaces (as the production facilities were called) produced a maximum of four million bushels of salt from this naturally occurring brine in 1864. However, these massive nineteenth-century furnaces are no longer standing. Industrial archaeology, with its goal of chronicling and preserving the history of industrial development, is used to document two of these salt furnaces—one (44SM280) in operation in the late eighteenth century when salt production was beginning, and the other (44SM139) in operation during the Civil War. Increasing size and sophistication in the exposed foundations of these structures is illustrated by the shift from predominantly stone-walled furnaces to later, larger structures with stacked brick walls. The size of the iron kettles used to cook the brine also increased to a 100-gallon capacity. These excavations corroborate historic descriptions of salt manufacture and provide important physical evidence of nineteenth-century industrial development.

The first isolate of Candida auris in China: clinical and biological aspects

The emerging human fungal pathogen Candida auris has been recognized as a multidrug resistant species and is associated with high mortality. This fungus was first described in Japan in 2009 and has been reported in at least 18 countries on five continents. In this study, we report the first isolate of C. auris from the bronchoalveolar lavage fluid (BALF) of a hospitalized woman in China. Interestingly, this isolate is susceptible to all tested antifungals including amphotericin B, fluconazole, and caspofungin. Copper sulfate (CuSO4) also has a potent inhibitory effect on the growth of this fungus. Under different culture conditions, C. auris exhibits multiple morphological phenotypes including round-to-ovoid, elongated, and pseudohyphal-like forms. High concentrations of sodium chloride induce the formation of a pseudohyphal-like form. We further demonstrate that C. auris is much less virulent than Candida albicans in both mouse systemic and invertebrate Galleria mellonella models.

High Concentrations of Sodium Chloride Improve Microbicidal Activity of Ibuprofen against Common Cystic Fibrosis Pathogens.

Ibuprofen (IBU-H), a widely used anti-inflammatory, also shows a marked antimicrobial effect against several bacterial species, including those involved in cystic fibrosis such as Pseudomona aeruginosa, methicillin resistant Staphylococcus aureus and Burkholderia cepacia complex. Additionally, our results show significant synergy between water soluble Na-ibuprofen (IBU-Na) and ionic strength. Salt concentrations above 0.5 M modify the zeta potential promoting the action of Na-IBU; thus, with 1 M sodium chloride, IBU-Na is ten times more efficient than in the absence of ionic strength, and the minimum effective contact time is reduced from hours to minutes. In short time periods, where neither IBU-Na nor controls with 1 M NaCl show activity, the combination of both leads to a reduction in the bacterial load. We also analyzed whether the changes caused by salt on the bacterial membrane also promoted the activity of other microbicide compounds used in cystic fibrosis like gentamicin, tobramycin and phosphomycin. The results show that the presence of ionic strength only enhanced the bactericidal activity of the amphipathic molecule of IBU-Na. In this respect, the effect of saline concentration was also reflected in the surface properties of IBU-Na, where, in addition to the clear differences observed between 145 mM and 1 M, singular behaviors were also found, different in each condition. The combination of anti-inflammatory activity and this improved bactericidal effect of Na-IBU in hypertonic solution provides a new alternative for the treatment of respiratory infections of fibrotic patients based on known and widely used compounds.

Effects of exogenous ouabain on endothelium‐dependent vascular function

Endogenous ouabain is an inhibitor of sodium‐potassium adenosine triphosphatase (Na+/K+‐ATPase, also known as sodium‐pump). It is released by high sodium chloride concentrations from the hypothalamus and the adrenal cortex. Upon its release in the circulation, endogenous ouabain increases arterial constriction and peripheral resistance hence arterial blood pressure. In the clinical setting, digoxin, targeting the sodium pump as well, is an orally active agent exerting inotropic effects to treat heart failure or atrial arrhythmias. But toxicity often occurs due to overdose. The present study aimed to investigate the local effects when the sodium pump is inhibited by exogenous ouabain in acute settings. Aortae isolated from male Sprague Dawley rats (12 weeks old) were cut into rings and incubated in the organ chambers with Krebs‐Ringer solution for isometric tension recording, in the absence or presence of ouabain. They were contracted with phenylephrine and relaxed with increasing concentrations of endothelium‐dependent and ‐independent vasodilators, acetylcholine (ACh) and DETA NONOate, or exogenous arachidonic acid (AA). Ouabain inhibited endothelium‐dependent relaxations to ACh and AA in a concentration‐dependent manner. It reduced the maximal relaxation to ACh in aortae with endothelium where the nitric oxide signaling pathway plays a dominant role in vasodilatation, and increased the half maximal effective concentration (EC50) of DETA NONOate. The inhibitory effect of ouabain on AA‐induced relaxations was not observed in the presence of indomethacin (cyclooxygenase inhibitor). Ouabain potentiated the relaxations to AA when endothelial potassium channels involved in endothelium‐dependent hyperpolarization (EDH) signalings [namely intermediate‐ and small‐conductance calcium‐activated potassium channels (IKCa and SKCa, respectively)] were blocked by TRAM‐34 and UCL1684, respectively; the relaxation was not affected by the inhibition, with barium, of inwardly‐rectifying potassium channels (KIR, which also play a role in EDH pathway). Taken in conjunction, ouabain likely impairs the nitric oxide and/or cyclooxygenase pathways to reduce endothelium‐dependent relaxations. When the major mechanisms for the generation of endothelium‐derived relaxing signals (namely, nitric oxide, prostanoids and EDH) are inhibited, ouabain unmasks the relaxation to AA that is independent of KIR activation.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Microbiological safety of processed meat products formulated with low nitrite concentration - A review.

Nitrite plays a major role in inhibiting the growth of foodborne pathogens, including Clostridium botulinum (C. botulinum) that causes botulism, a life-threatening disease. Nitrite serves as a color-fixing agent in processed meat products. However, N-nitroso compounds can be produced from nitrite, which are considered as carcinogens. Thus, consumers desire processed meat products that contain lower concentrations (below conventional concentrations of products) of nitrite or no nitrite at all, although the portion of nitrite intake by processed meat consumption in total nitrite intake is very low. However, lower nitrite levels might expose consumers to risk of botulism poisoning due to C. botulinum or illness caused by other foodborne pathogens. Hence, lower nitrite concentrations in combination with other factors such as low pH, high sodium chloride level, and others have been recommended to decrease the risk of food poisoning. In addition, natural compounds that can inhibit bacterial growth and function as color-fixing agents have been developed to replace nitrite in processed meat products. However, their antibotulinal effects have not been fully clarified. Therefore, to have processed meat products with lower nitrite concentrations, low pH, high sodium chloride concentration, and others should also be applied together. Before using natural compounds as replacement of nitrite, their antibotulinal activities should be examined.

Effectiveness of Prepared Corn Husk Activated Carbon on the Abatement of Sodium Chloride Content in Fish Sauce

Fish sauce is a salt-fermented product that is an economically important fishery product in most Southeast Asian countries. In this study, high sodium chloride content of fish sauce was reduced by environmental friendly adsorbent from agricultural waste (corn husk). The production of activated carbon from agricultural by-product has potential economic and reducing environmental impacts. Corn husk activated carbon was prepared by chemical activation method using zinc chloride (ZnCl2) as activating agent. The effect of various preparation parameters such as concentration of activating agent, carbonization temperature and carbonization time that depend on characteristics of activated carbon. Based on the results of the characterization studies, the activated carbon prepared by impregnation the precursor with 20% ZnCl2, followed by carbonization at 250℃ for 40 min., was selected as the appropriate condition due to the following good characteristics of activated carbon: high surface area, high iodine sorption capacity, and SEM analysis. In reduction of sodium chloride content in fish sauce, the ratio of 1:50 activated carbon to fish sauce for 120 min. agitation time at 30℃ was effectively reduced from 31.5 to 26.34 (%w/w). The effective reduction of sodium chloride from commercial fish sauce was significantly observed by processed corn husk activated carbons.

Cementitious materials exposed to high concentration of sodium chloride solution: Formation of a deleterious chemical phase change

This paper investigates deleterious chemical interactions between cementitious materials and high concentrations of sodium chloride (NaCl) solution (i.e., salt concentration >12% by mass). The behavior of mortar specimens made using Type I and Type V ordinary portland cements was investigated as the temperature varied in the presence of NaCl solution with concentrations of 15% and 20% (by mass). A low-temperature longitudinal guarded comparative calorimeter (LGCC) in conjunction with an acousto-ultrasonic technique were used to monitor the damage development in mortar samples. Cooling-heating cycles were applied with a minimum temperature above the freezing temperature of the solution to avoid ice formation. Nevertheless, damage was observed in specimens. Calcium aluminate phases, mainly tricalcium aluminate (C3A), seem to be the source of damage as the magnitude of damage was relatively minor when Type V cement (C3A < 5% by mass) was used. To further investigate the source of the damage, a low-temperature differential scanning calorimeter (LT-DSC) was used to study chemical phase transitions during temperature change in three types of powder specimens exposed to different concetrations of NaCl solution: (1) hydrated cement pastes, made using Type I and Type V cements, (2) cement pure phases, consisting of C3A and gypsum, and (3) cement hydration products, consisting of calcium hydroxide (CH) and calcium sulfoaluminate phases (monosulfate (AFm) and ettringite (AFt)). A formation of a chemical phase at a temperature range between 0 °C and 10 °C was observed that may be the source of damage in cementitious materials exposed to high concentration of NaCl solutions. It was found that the interaction of high concentrations of NaCl solution with C3A and calcium sulfoaluminate phases in the cementitious system are the origin of the chemical phase formation.

Destruction of shells and release of a protein from microcapsules consisting of non-biodegradable polyelectrolytes

ABSTRACTUsing fluorescent spectroscopy, we examined degradation of PAH/PSS microcapsule shells and release of a protein from them. The processes were controlled by various concentrations of NaCl and (NH4)2SO4 and levels of pH: 5 and 7.4. We found that a high concentration of sodium chloride (2 М) causes essential dissociation of PAH from the upper shell layer and explained this by the layer loosening under the ionic strength. Using the optical spectroscopy, we determined amount of a microcapsule polyelectrolyte (PAH) and found that less than 20% of it can be released into 2М NaCl solution, and only 2% can be released into the water medium. Increase in solution pH up to 7.4 causes peeling of PAH too, however, temperature increase up to 37°С decreases this effect due to the structuring and compacting of the shell demonstrated by electron-microscopic studies. And finally we found that a scarce release of an encapsulated protein from the microcapsules does not depend on the presence of salts in the medium, their concentrations and a medium pH.

Raman Imaging of the Distribution of Carotenoids in Haematococcus Pluvialis Under High Concentration of Sodium Chloride

Carotenoids have important implications for maintaining normal cell activity, antioxidant and photosynthesis. Under some extremely hard conditions, the algae cells will produce a large number of carotenoids to resist the stress. The mechanism of algae cell emergency response has attracted a lot of attention. Here, Raman spectroscopy was applied to study the distribution of carotenoids in living algae cells under high concentration of sodium chloride. Multivariate analysis (MCR) was also used to resolve the corresponding Raman spectra of different carotenoids. By MCR analysis, we succeeded in distinguishing the distribution of different pigment cells. This method of analysis can be widely used in the study of mechanism of cellular stress response.

The Designer Antimicrobial Peptide A-hBD-2 Facilitates Skin Wound Healing by Stimulating Keratinocyte Migration and Proliferation

Background/Aims: Antimicrobial peptides are effective promoters of wound healing but are susceptible to degradation. In this study, we replaced the GIGDP unit on the N-terminal of the endogenous human antimicrobial peptide hBD-2 with APKAM to produce A-hBD-2 and analyzed the effect on wound healing both in vitro and in vivo. Methods: The effects of A-hBD-2 and hBD-2 on cytotoxicity and proliferation in keratinocytes were assessed by Cell Counting Kit-8 assay. The structural stability and antimicrobial activity of hBD-2 and A-hBD-2 were evaluated against Staphylococcus aureus. RNA and proteins levels were evaluated by real-time PCR and western blotting, respectively. Cell migration was evaluated using a transwell assay. Cell cycle analysis was performed by flow cytometry. Wound healing was assessed in Sprague-Dawley rats. Epidermal thickness was evaluated by hematoxylin and eosin staining. Results: We found that hBD-2 exhibited cytotoxicity at high concentrations and decreased the structural stability in the presence of high sodium chloride concentrations. A-hBD-2 exhibited increased structural stability and antimicrobial activity, and had lower cytotoxicity in keratinocytes. A-hBD-2 increased the migration and proliferation of keratinocytes via phosphorylation of EGFR and STAT3 and suppressed terminal differentiation of keratinocytes. We also found that A-hBD-2 elicited mobilization of intracellular Ca²⁺ and stimulated keratinocytes to produce pro- and anti-inflammatory cytokines and chemokines via phospholipase C activation. Furthermore, A-hBD-2 promoted wound healing in vivo. Conclusion: Our data suggest that A-hBD-2 may be a promising candidate therapy for wound healing.

Hypernatremia and acute pancreatitis in chronic kidney disease: back to the salt mines. Answers

Acute pancreatitis can be a life-threatening complication in patients with chronic kidney disease (CKD), especially in kidney transplant recipients. The patient was 7 years old when he received renal transplantation for CKD secondary to posterior urethral valves. Two years later, he presented with severe necrotizing pancreatitis (Ranson’s score 5, Balthazar’s score 8). Viral and genetic testing came back negative; pancreatitis was attributed to the patient’s treatments (prednisone, trimethoprim-sulfamethoxazole, and everolimus). Twenty days later, necrotized pancreatic cysts had formed. Two drains were surgically inserted into the abdomen, and continuous cyst lavage was started with normal saline solution. Two days later, blood tests revealed severe hypernatremia and hypokalemia. We suspected unwanted peritoneal dialysis had occurred because of the high sodium chloride content and the absence of potassium in the normal saline solution being used for cyst lavage. We switched to a peritoneal dialysis solution for the lavage, leading to complete correction of hydroelectrolytic disorders. Acute pancreatitis is a frequent and potentially severe complication in CKD patients. It should be suspected in the presence of nonspecific symptoms, such as abdominal pain or vomiting. Rigorous monitoring of electrolytes is also mandatory for managing CKD patients with acute pancreatitis.

Germination Ecology of Two Australian Biotypes of Ragweed Parthenium (Parthenium hysterophorus) Relates to Their Invasiveness

Ragweed parthenium is a highly invasive weed species in several countries, including Australia. Laboratory experiments were conducted to evaluate the effect of temperature, light, salinity, pH, and moisture on germination of two Australian biotypes of ragweed parthenium: Clermont (highly invasive) and Toogoolawah (noninvasive). Although seeds of both biotypes could germinate under complete darkness, germination was improved by 20% to 49% under a 12-h photoperiod. Both biotypes germinated over a wide range of constant (8 to 35 C), and alternating day/night (15/5 to 35/25 C) temperatures. However, the Clermont biotype exhibited significantly higher germination than Toogoolawah biotype over the range of temperatures studied. Highest germination of Clermont (100%) and Toogoolawah (97%) was observed at constant temperatures of 14 to 23 C and 23 C, respectively. The best alternating day/night temperature for germination of both biotypes was 25/15 C. Clermont also germinated better than Toogoolawah under osmotic- and salt-stress conditions. Osmotic stress had moderate negative effects on germination, with 52% and 36% of the Clermont and Toogoolawah seeds able to germinate at −0.60 MPa, respectively. Complete germination inhibition for both biotypes was observed at an osmotic potential of −1.2 MPa. Both biotypes also germinated at a very high sodium chloride (NaCl) concentration of 250 mM. A 50% reduction in germination of Toogoolawah and Clermont was caused by 99 and 154 mM NaCl, respectively. Germination of the Clermont biotype was not affected by a wide range of pH (4.0 to 10.0), whereas the strong acidic and alkaline pH levels (4.0 and 10.0) caused 18% and 25% reductions in germination of the Toogoolawah biotype compared with control. The Clermont biotype had a higher ability to germinate across all treatments compared with the Toogoolawah biotype, which might be a contributing factor toward the high invasive ability of the former compared with the latter.

Microorganisms Oxidize Iron (II) Ions in the Presence of High Concentrations of Sodium Chloride - Potentially Useful for Bioleaching

Acidophilic leaching microorganisms have been reported to be in general intolerant to high salinity, namely high concentrations of chloride. At present this restriction hampers the use of sea water for bioleaching technology. Enrichment cultures obtained in this study from a former ore deposit near the Spanish coast oxidize ferrous iron in the presence of up to 50 gL-1 NaCl at pH 2.5 and 37°C. The presence of at least 5 gL-1 NaCl was shown to be an obligate requirement for iron oxidation. The major microbial groups comprise Alicyclobacillus and Arthrobacter. The findings may be of biotechnological relevance.