Margalith Galun

Pigment extraction from lichens with dimethyl sulfoxide (DMSO) and estimation of chlorophyll degradation

Abstract Photosynthetic pigments from Romalina duriaei were extracted by immersion of the thalli in dimethyl sulfoxide (DMSO). Extraction was complete and the extract was found to be stable in the dark at 4°C for 10 days. The extract was measured spectrophotometrically at the blue and red region of the absorption spectrum and the ratio OD435/OD415 mm was found to be a preferable parameter for estimating chlorophyll degradation to phaeopigments. It is shown that Arnons equation for quantification of total chlorophyll can be used with DMSO extracts too.

Removal of metal ions from aqueous solutions by Penicillium biomass: Kinetic and uptake parameters

The uptake and binding of Ni, Zn, Cd, and Pb by the mycelium of Penicillium digitatum are highly pH-sensitive, being severely inhibited below pH 3. In the case of Ni, Zn, and Cd, H+ inhibits competitively. The Cu-ion, like UO22+ studied previously, is nearly pH-insensitive. All of these cations except Pb are taken up to a greater extent by mycelial preparations preheated at 100° C for 5 min. Other activators include alkali and dimethyl sulfoxide (DMSO) pretreatment, but formaldehyde inhibits, Combining current and previous data, the ion-selective character of uptake is reflected, on a molar basis by the rank order Fe3+, Ni2+ Zn2+ > Cu2+ > Pb2+ UO22+ ≫ MoO42−. P. digitatum appears to act like a mixture of neutral and acidic glycans with no real evidence for cationic amino-functional sites. In addition to the technological applications in water treatment, we suggest that fungal biosorption may be of natural geochemical importance in the concentration of metals and formation of minerals.

Removal of Uranium(VI) from Solution by Fungal Biomass and Fungal Wall-Related Biopolymers.

Penicillium digitatum mycelium can accumulate uranium from aqueous solutions of uranyl chloride. Azide present during the uptake tests does not inhibit the process. Killing the fungal biomass in boiling water or by treatment with alcohols, dimethyl sulfoxide, or potassium hydroxide increases the uptake capability to about 10,000 parts per million (dry weight). Formaldehyde killing does not enhance the uranium uptake. The inference that wall-binding sites were involved led to the testing of uranium uptake by chitin, cellulose, and cellulose derivatives in microcolumns. All were active, especially chitin.

Filamentous fungi as metal biosorbents: A review

Common filamentous fungi (e.g. Penicillium spp, Rhizopus spp) serve as sources of highly effective heavy metal biosorbents. Derivatives of fungal biomass range from purified cell wall fractions to whole, heat killed mycelium otherwise unmodified. Limited trials suggest a moderate degree of regenerability. When compared with commercial ion-exchange resins, carbons and metal oxides, fungal derivatives generally perform well. Fungal systems offer considerable versatility with respect to metals taken up and bound including the cations Fe, Ni, Cu, Zn, Ag, Cd, La, Pb, Th, and U as well as Cr and Mo anions. Versatility also extends to physico-chemical conditions such as pH and heat tolerance. A deterrent to the application of these materials to waste water management has been a lack of standardized conditions along with the inability to make interspecies comparisons. However, potentials for use of filamentous fungi as biosorbents and their tailoring by genetic techniques to meet specific needs, recommend them for further research and development.

Heavy metals in the lichen Caloplaca aurantia from urban, suburban and rural regions in Israel (a comparative study)

The content of eight heavy metals: Mn, Zn, Fe, Pb, Ni, Cu, Cr and Cd in the lichen Caloplaca aurantia growing on roof-tiles in urban, suburban and rural settlements in Israel has been evaluated. The data obtained and their statistical analysis indicated the following: (1) The content of all the above listed metals was generally higher in the lichen growing in ‘town’ than in ‘village’ areas; among these metals Ni and Zn were found most suitable for the distinction between ‘town’ and ‘village’ settlements. (2) Comparisons of the coefficient of variation of metal content values in ‘town’ versus ‘village’ furnished indications on the dispersion capacity of the metal particles. (3) Correlation analysis among the metals in ‘town’ and ‘village’ resulted in suggestive information on the emission sources. (4) Leaching tests indicated the tenacity of metal retainment and incorporation efficiency into the lichen tissue. Lichen species like C. aurantia, which grow both in ‘clean’ and metal contaminated areas are suggested as comparative monitors and for assessing periodical changes in metal output and concentrations.

Correlation between chlorophyll degradation and the amount of some elements in the lichen Ramalina duriaei (de not.) Jatta

Abstract The lichen Ramalina duriaei was transplanted to 13 biomonitoring stations for one year. The pigments of the transplanted lichen thalli and of indigenous R. duriaei thalli were then extracted with DMSO and the ratio OD 435/OD 415 used to estimate chlorophyll degradation in comparison with this ratio in control samples. The ratio values decreased with increase in amounts of Br, Pb, Fe and Ti. There was no significant correlation between the amount of sulphur, calcium, chlorine, strontium, zinc and phosphorus in the lichen and chlorophyll degradation.

Recovery of uranium (VI) from solution using preculturedPenicillium BIOMASS

PreculturedPenicillium biomass can accumulate U from solutions of uranyl chloride. A 4 g (fresh weight) fungal mass will remove, over a 1 to 4 h period, between 20 and 30 °C, 75 to 90% of the UO2-ion from 1 to 10 ppm solutions. Accumulation is more or less the same between pH 5.5 to 7.5, and retains over 2/3 of its efficiency at pH 2.5. Boiling, pasteurization and trichloracetic acid pretreatment do not reduce and may increase fungal efficiency. Preculture with Tween 80 improves efficiency by its effect on formation of small beaded mycelial masses.

Proteins from the lichenXanthoria parietina which bind to phycobiont cell walls. Correlation between binding patterns and cell wall cytochemistry

SummaryA protein fraction was isolated from the lichenXanthoria parietina which bound to the appropriate cultured phycobiont, but not to the freshly isolated symbiotic alga. The protein also appeared to discriminate between five other strains of cultured phycobionts from different lichens; phycobionts isolated from lichens in the familyTeloschistaceae bound the protein whereas phycobionts isolated from lichens in other families did not. Using cytochemical techniques, it was shown that protein binding ability was correlated with high levels of acidic polysaccharide in the cell wall, and the presence of a protein coat on the cell wall surface of the phycobiont. The possible role of this protein in recognition between lichen symbionts is briefly discussed.

Structural modifications of the phycobiont in the lichen thallus

SummaryModifications in the fine structure of the algal component of two lichens,Aspicilia sp. andSquamarina crassa v.crassa, have been studied. It has been pointed out that fungal penetration is not essential for the mutual relationship between the two symbionts of the lichen thallus. The structural changes taking place during the life cycle of the phycobiont of the two lichens examined are not a response to fungal invasion.Careful examinations of serial sections revealed an interesting correlation between the growth pattern of the thallus and the distribution of the algal cells in the algal layer.

“Oil hyphae” of endolithic lichens and their fatty acid composition

SummaryThe structure of medullary oil hyphae of twelve endolithic lichen species, belonging to different taxa and colonizing different habitats, was examined by light and electron microscopy. The chemical composition of lipids isolated from the oil hyphae and from two corresponding mycobionts grown in culture was determined.The oil hyphae of the various species appeared in different forms and contained large amounts of lipid in the form of oil globules. The hyphae of mycobionts isolated from two of the endoliths and grown in culture also contained large amounts of lipids. Triacylglycerol was the predominant lipid component in all the organisms examined. Hexadecanoic acid was the main saturated fatty acid; octadecenoic acid and octadecdienoic acid the predominant unsaturated fatty acids. Tetradecanoic, hexadecenoic, octadecanoic and octadectrienoic acids were also detected.The fatty acid distribution pattern appeared unaffected by the nature of substrate and climatic conditions. There is a certain similarity in the fatty acid composition in related species.