Stereoselective formation of a K-region dihydrodiol from phenanthrene by Streptomyces flavovirens

The metabolism of phenanthrene, a polycyclic aromatic hydrocarbon (PAH), by Streptomyces flavovirens was investigated. When grown for 72 h in tryptone yeast extract broth saturated with phenanthrene, the actinomycete oxidized 21.3% of the hydrocarbon at the K-region to form trans-9,10-dihydroxy-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol). A trace of 9-phenanthrol was also detected. Metabolites isolated by thin-layer and high performance liquid chromatography were identified by comparing chromatographic, mass spectral, and nuclear magnetic resonance properties with those of authentic compounds. Experiments using [9-¹⁴C]phenanthrene showed that the trans-9,10-dihydrodiol had 62.8% of the radioactivity found in the metabolites. Circular dichroism spectra of the phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was (–)-9S,10S, the same as that of the principal enantiomer produced by mammalian enzymes. Incubation of S. flavovirens with phenanthrene is an atmosphere of ¹⁸O₂, followed by gas chromatographic/mass spectral analysis of the metabolites, indicated that one atom from molecular oxygen was incorporated into each molecule of the phenanthrene trans-9,10-dihydrodiol. Cytochrome P-450 was detected in 105,000×g supernatants prepared from cell extracts of S. flavovirens. The results show that the oxidation of phenanthrene by S. flavovirens was both regio- and stereospecific.Abbreviations CD circular dichroism - DMF N,N-dimethyl-formamide - GC/MS gas chromatography/mass spectrometry - HPLC high performance liquid chromatography - NMR nuclear magnetic resonance - ODS octadecylsilane - PAH polycyclic aromatic hydrocarbon - TLC thin-layer chromatography - TMS tetramethylsilane - UV ultraviolet     

Calcium-binding protein in sieve tube exudate

A calcium-binding macromolecule, with an estimated molecular weight greater than 100,000, was detected in phloem exudate from Cucurbita maxima and related species. The macromolecule was a component of sieve tube sap, rather than a contaminant leached from cell walls or cut parenchyma cells during exudate collection. The protein nature of this macromolecule was deduced from its size, lability, susceptibility to proteolytic digestion, and by the dependence of calcium-binding activity on thiol-protecting agents. This protein is distinct from the major proteins of exudate and does not appear to be related to calmodulin.Abbreviations SDS-PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis - CBP calcium-binding protein     

Factors affecting the resistance of cold-stored carrots to Botrytis cinerea

The secondary phloem parenchyma of cold-stored turgid roots of carrot (Daucus carota) is capable of localizing mycelial infection by Botrytis cinerea, producing a dark resistant lesion. The percentage of roots exhibiting this reaction declined with increasing time in cold-store: when freshly harvested and wound-inoculated in October 1974, 99%of roots resisted invasion, whereas only 5% of those stored until March 1975 did so. The surface dimensions of resistant lesions did not increase between 33 and 55 days after inoculation. However, the surface dimensions and mean weights of lesions (arising from inoculations performed at different times over the course of the storage season) were both larger with increasing time in storage of roots prior to inoculation. The ability of the root tissue to localize infection was reduced if the roots lost 5–10% or more of their fresh weight before inoculation, resulting progressively in susceptibility. Compared with roots wound-inoculated using mycelial disks, there was an overall reduction in infection when carrots were wound-inoculated using conidia or when conidia or mycelial disks were inoculated onto the apparently undamaged surface of roots.     

Penetration into rice tissues by brown planthopper and fine structure of the salivary sheaths

The fine structure of the salivary sheaths in plant tissues can provide important information on homopteran probing and ingestion behaviors. Salivary sheaths secreted by the brown planthopper (BPH), Nilaparvata lugens (Stål) (Homoptera: Delphacidae), and their tissue pathway were investigated using light, scanning electron, and transmission electron microscopy. About half of the salivary flanges on the surface of the food substrate were connected with internal salivary sheaths. Only 43% of the salivary sheaths showed side branches. Many sculpture‐like protuberances and small cavities had been formed on the outer surface of the salivary sheath, but the sheath lumen circumferences were sealed. Brown planthoppers showed a preference for probing and leaving salivary sheaths in the susceptible rice variety TN1 rather than in the resistant variety B5 during the first 2 days of the experiments. The salivary sheaths in rice tissues reached the inner tissue layer of the leaf sheaths and stems, but were mostly observed to end in the first and second layer of the leaf sheaths. Brown planthoppers also preferred to probe into the thick segment of the outer leaf sheath. After ingestion by the insect, the cytoplasm in both phloem and companion cells degraded and the main organelles were lost. Numerous small vesicles were found in most of the phloem cells, but cell walls remained intact. Large numbers of symbiont‐like structures were observed inside the salivary sheath lumen. These results indicated that BPH has complicated feeding behaviors, which warrants further investigation.     

On the cell wall composition ofSaccharomycopsis guttulata

Summary Cells ofSaccharomycopsis guttulata were ruptured by sonic oscillation and the resulting cell walls were purified by washing and centrifugation. The walls contained 43.7% carbohydrate (expressed as glucose), 39.6% protein and a trace of chitin. Paper chromatography of hydrolyzed cell walls showed that glucose and an unknown reducing compound make up the bulk of the carbohydrate fraction. Mannose and glucosamine were present in small amounts. The cell wall composition ofS. guttulata appears to differ considerably from that ofS. cerevisiae.     

Ruminococcus flavefaciens Cell Coat and Adhesion to Cotton Cellulose and to Cell Walls in Leaves of Perennial Ryegrass (Lolium perenne)

Ruminococcus flavefaciens was shown to possess a prominent glycoprotein coat, which contained rhamnose, glucose, and galactose as its principal carbohydrates. Periodate-reactive carbohydrate occurred as a surface layer of the coat. The ruminococci adhered strongly by means of this coat to cotton cellulose and to cell walls in leaf sections of Lolium perenne L. (perennial ryegrass). The coat was diffuse at the point of contact so that the bacterial cell wall was in close contact with the substrate. Adhesion was influenced by the availability of damaged plant cell walls and by the cell wall type and occurred most rapidly to cell walls of the epidermis and sclerenchyma, followed by the phloem and mesophyll. Plaques of bacteria with filamentous coat extensions developed on all these tissues. The bacteria did not readily adhere to the walls of the bundle sheath cells or metaxylem or protoxylem vessels and did not adhere to the cuticle or chloroplasts. The epidermal and phloem cell walls were more rapidly digested than the walls of other cell types.     

Onset of Phloem Export from Senescent Petals of Daylily

During senescence, petals of attached daylily (Hemerocallis hybrid cv Cradle Song) flowers lost 95% sugar and 65% dry weight over the first 24 h, with 30% of dry weight loss coming from nonsugar components. Detaching flowers did not delay senescence, but halted loss of carbohydrate and amino acid, suggesting that loss in the intact state was due to phloem export. Petal autolysis occurred mainly in the interveinal parenchyma, causing vascular strands to begin separating from the petal mass. Such vascular strands still stained with tetrazolium and accumulated sucrose, indicating a retained viability. Their sucrose accumulation rates were high in comparison with those of other plant tissues, and the accumulated product was mainly sucrose. Sucrose synthesis took place in the senescent petal, and sucrose was the principal sugar in phloem exudate, whereas hydroxyproline and glutamine were the main transport amino acids. [14C]Sucrose applied to attached senescent flowers was rapidly translocated to other parts of the plant, particularly developing flower buds. Thus, onset of phloem export allowed most of the soluble carbohydrate and amino acid in the senescing flower to be retrieved by the plant. Additional salvaged material came from proteins and possibly from structural carbohydrate. Over a 12-h period, the flower switched from acting as a strong carbohydrate sink during expansion to become a strong source during senescence. This rapid reversal offers potential for phloem transport studies.     

Adhesion of Bacteroides succinogenes in pure culture and in the presence of Ruminococcus flavefaciens to cell walls in leaves of perennial ryegrass (Lolium perenne)

Bacteroides succinogenes and Ruminococcus flavefaciens are two of the most important cellulolytic bacteria in the rumen. Adhesion of B. succinogenes in pure culture, and in mixed culture with R. flavefaciens, to the various types of cell walls in sections of perennial ryegrass (Lolium perenne L. cultivar S24) leaves was examined by transmission and scanning electron microscopy. B. succinogenes adhered to the cut edges of most plant cell walls except those of the meta- and protoxylem. It also adhered, though in much smaller numbers, to the uncut surfaces of mesophyll, epidermal, and phloem cell walls. In mixed culture, both species adhered in significant numbers to the cut edges of most types of plant cell wall, but R. flavefaciens predominated on the epidermis, phloem, and sclerenchyma cell walls. B. succinogenes predominated on the cut edges and on the uncut surfaces of the mesophyll cell walls, and its ability to adhere to uncut surfaces of other cell walls was not affected by the presence of the ruminococcus. Both organisms rapidly digested the epidermal, mesophyll, and phloem cell walls. Zones of digestion were observed around bacteria of both species when attached to the lignified cell walls of the sclerenchyma, but not when attached to the lignified xylem vessels.     

Adhesion of Bacteroides succinogenes in pure culture and in the presence of Ruminococcus flavefaciens to cell walls in leaves of perennial ryegrass (Lolium perenne).

Bacteroides succinogenes and Ruminococcus flavefaciens are two of the most important cellulolytic bacteria in the rumen. Adhesion of B. succinogenes in pure culture, and in mixed culture with R. flavefaciens, to the various types of cell walls in sections of perennial ryegrass (Lolium perenne L. cultivar S24) leaves was examined by transmission and scanning electron microscopy. B. succinogenes adhered to the cut edges of most plant cell walls except those of the meta- and protoxylem. It also adhered, though in much smaller numbers, to the uncut surfaces of mesophyll, epidermal, and phloem cell walls. In mixed culture, both species adhered in significant numbers to the cut edges of most types of plant cell wall, but R. flavefaciens predominated on the epidermis, phloem, and sclerenchyma cell walls. B. succinogenes predominated on the cut edges and on the uncut surfaces of the mesophyll cell walls, and its ability to adhere to uncut surfaces of other cell walls was not affected by the presence of the ruminococcus. Both organisms rapidly digested the epidermal, mesophyll, and phloem cell walls. Zones of digestion were observed around bacteria of both species when attached to the lignified cell walls of the sclerenchyma, but not when attached to the lignified xylem vessels.     

The Antigens Associated with the Cell Walls of Members of the Genus Pseudomonas

Three antigens were associated with the cell walls of pseudomonads. A highly antigenic, strain-specific antigen of high molecular weight and protein or lipoprotein in nature, occurred as an envelope around the cells. It could be washed off the cells closely associated with carbohydrate material but its antigenicity was not dependent on the carbohydrate present. Another antigen, common to all strains tested, was situated below the first antigen. This was less antigenic than the strain-specific antigen and was polysaccharide or lipopolysaccharide in nature. A second common antigen was the mucopeptide of the cell walls. This had an antigenicity similar to that of the second antigen and was dependent on both the carbohydrate and polypeptide components of the macromolecule. There appears to be some correlation between these findings and the structure of cell walls of pseudomonads are shown by electron microscopy.     

Water Relation Alterations Observed during Hypersensitive Reaction Induced by Bacteria

Upon exposure to pathogenic bacteria, resistant and nonhost plants undergo a hypersensitive reaction (HR) that is expressed as rapid plant cell death. If sufficient concentrations of these bacteria are inoculated to such plant tissue, then that portion of the tissue rapidly collapses and becomes necrotic. As the tissue collapses the water relations of inoculated tissues become markedly disturbed. We measured a decline in the relative water content (RWC) in the leaf-like cotyledons of cotton (Gossypium hirsutum cv Immune 216) within the first 4 h (cut at 1 h) after inoculation with Pseudomonas syringae pv tabaci. However, the decrease in RWC was not caused by a decrease in initial fresh weight but by increased water uptake during incubation in water. By 8 h after inoculation, cotyledons still on the plant had lost turgidity, and their area decreased. K+ efflux was also observed concurrently with the decrease in RWC, providing a reason for the loss of turgidity in the tissue. These observations suggest that cells lose turgor and change shape from cylinders with large intercellular spaces to those of a more tabular shape. During this change cell walls come closer together, providing an avenue for increased water uptake through capillary action. The stomatal diffusive resistance of intact cotyledons increased; hence, water loss through stomata is not the cause of the observed wilting and RWC decline. An increase in K+ per dry weight suggests that phloem loading or movement may also be impaired during bacterially induced HR.     

Effects of low light on phloem ultrastructure and subcellular localization of sucrose synthase in <Emphasis Type="Italic">Prunus persica</Emphasis> L. var. <Emphasis Type="Italic">nectarina</Emphasis> Ait. fruit

Using electron microscopy, the ultrastructure of phloem unloading zone was examined in the Prunus persica L. var. nectarina Ait. fruit. Our study showed that, in the SE/CC (sieve element/companion cell) complexes, CC developing under low light had a thin cytoplasm layer with few mitochondria and numerous small vacuoles, and not clearly seen nuclei. The cytoplasm vacuolation indicated that the cytoskeleton was destroyed at low light. The effects of low light on CC development suggest that unloading evidently linked to the low accumulation of soluble sugars by fruit. At the young fruit stage, flesh parenchyma around the phloem tissue had no starch grains in the plastids in fruit developing under low light. This is a further indication that less photoassimilates was translocated from source leaves to fruit sinks under low light during the young fruit developmental stage. The activity of sucrose synthase (SuSy), the key enzyme of sucrose metabolism in fruit, increased dramatically during fruit maturation. The highest SuSy activity during the rapid fruit growth phase suggests that sink strength could be correlated with the SuSy activity. The high SuSy activity under normal light possibly indicates that fruit had a capacity to utilize sucrose irrespective of their site of phloem unloading. Immunogold electron microscopy showed that SuSy was localized mainly in the vacuole of flesh parenchyma cells. The vacuole-localized SuSy can hydrolyze sucrose imported from the phloem, which may explain the apparent correlation between SuSy activity and phloem unloading. The double sieve element (SE/SE) complexes occurred in a greater number and had thicker cell walls under normal light intensity than under low light intensity. These data demonstrate clearly that low light decreased SuSy activity in the control of phloem unloading. Published in Russian in Fiziologiya Rastenii, 2009, Vol. 56, No. 4, pp. 509–517. This text was submitted by the authors in English.     

Histopathological changes in susceptible corn inoculated with Helminthosporium maydis race O

Seedlings of a susceptible inbred line of male-fertile corn were inoculated with conidia of Helminthosporium maydis race O. Histological and ultrastructural observations of mesophyll, bundle sheath and phloem were made over a period of 8 days. Histological observations at 1 day revealed that lesions were comprised of several dead mesophyll cells bordered by a pair of vascular bundles. By 3 days lesions had developed their characteristic appearance caused by mesophyll collapse and had increased to a width of 10–12 bundles. At the ultrastructural level, the first signs of mesophyll cell change were rupture of the tonoplast and swelling of the mitochondrial matrix followed by a disintegration of the cytoplasm and swelling of the chloroplast stroma. Following these changes the cytoplasm became filled with an electron dense material and the plasmalemma ruptured leaving only partial remnants of chloroplasts as recognizable organelles. All of these changes occurred by 1 day. Bundle sheath cells were more resistant and intact cells could be observed in 3-day-old lesions. Phloem showed signs of degeneration by 1 day with distortion of the sieve-tube element membranes and disintegration of the companion cell cytoplasm. By 4 days the phloem had disintegrated.     

Bioleaching of Uranium From Egyptian Rocks Using Native Actinomycete Strains

Bioleaching is an economic, novel practice for extraction of metals from their sources by microorganisms. The current study aimed to extract uranium from Egyptian ores using native strains of actinomycetes. Two types of rocks and one ore sample were collected from west-central Sinai, Egypt. Major oxides of the samples and fourteen heavy metals, including uranium, were determined. X-ray diffraction analysis proved that uranium was present in the samples in various structures. Uranium was present in different concentrations, 220, 770, and 550 mg/kg in sandstone, granite, and manganese ore, respectively. Thirty-four actinomycete isolates were recovered from the studied samples using four different isolation media. Acid production capabilities were employed to select isolates for further leaching experiments. Bioleaching experiments were carried out using sterile and non-sterile ore samples. Using sterile ore samples, the highest solubilization percentages of U₃O₈ were 44.5, 38.55, and 16.76% from sandstone, manganese ore, and granite sample, achieved by isolates UA12, UA5, and U7, respectively. Lower solubilization percentages of U₃O₈ were recorded by using non-sterile ore samples. Investigating the factors affecting the bioleaching abilities of the tested organisms revealed that 10 days of incubation with 4% pulp density were the best conditions for U₃O₈ solubilization. The most efficient isolates were identified using 16S rRNA gene sequence analysis. UA12 identified to be Streptomyces bacillaris, while UA5 could not be identified, and U7 was assigned as uncultured bacterium clone. Scanning electron microscope examination of the bioleaching experiment showed different growth intensity within the active isolates. For larger-scale extraction purposes, a kilogram of sandstone, containing 220 mg of U₃O₈, was used in the form of a truncated cone in a heap leaching experiment. After 20 cycles, 14.72 mg/l (6.7%) of U₃O₈ was leached by S. bacillaris, while 19.36 mg/l (8.8%) of U₃O₈ was leached by chemical leaching using sulfuric acid. The results of this study prove that the extraction of uranium using actinomycetes could be exploited as less polluting, more economical, and more effective than traditional chemical extraction especially from low-grade ores or mining wastes.     

Growth and nutrition of mycorrhizal guayule plants*

Synthesis of mycorrhiza in guayule plants was achieved by inoculation of 8-day-old seedlings with hyphae and chlamydospores of an undescribed Glomus species. There was a five-fold increase in total dry weight of 30-day-old mycorrhizal- compared to nonmycorrhizal-guayule grown in sterile loamy-sand without additional fertiliser. Thirty-day-old, inoculated- and uninoculated-seedlings were transplanted to sterile or unsterile soil and grown an additional 60 days. The greatest total dry weight of guayule was attained by inoculated transplants grown in sterile soil. Inoculated transplants increased two- to three-fold in total dry weight compared to uninoculated transplants, both grown in unsterile soil. After 90 days, uninoculated plants grown in unsterile soil had formed mycorrhizae with resident vesicular-arbuscular mycorrhizal fungi to the same extent as inoculated-plants grown in unsterile soil. Total mineral uptake increased in inoculated guayule, irrespective of soil treatment or the presence of resident VA mycorrhizal fungi.     

THE PHLOEM OF ETAPTERIS LECLERCQII AND BOTRYOPTERIS TRIDENTATA

The phloem of Etapteris leclercqii and Botryopteris tridentata petioles is described from Lower Pennsylvanian coal balls. Petioles of B. tridentata are characterized in transverse section by an omega-shaped xylem trace, a phloem zone which extends from 2-10 cells in width, and 2-parted cortex. Etapteris leclercqii petioles exhibit a 4–9 cell-wide phloem zone surrounding the central clepsydroid xylem mass, and a 3-parted cortex. In both taxa a 1–2 cell layer parenchyma sheath separates the xylem from the extra-xylary tissues. The phloem of both species consists of sieve elements that average about 20 μm in diam by 200 μm in length in Botryopteris, and 100 μm in length in Etapteris, with horizontal-slightly oblique end walls. In transmitted light, the radial walls of the sieve elements form an irregular reticulate pattern enclosing elliptical lighter areas. With the scanning electron microscope, these areas appear as horizontal-slightly oblique furrows on the cell wall, with many small indentations lining the furrows. These indentations, because of their regular occurrence and size (from a few fractions of a micron up to 1.0 μm in diam), are interpreted as sieve pores, and the elliptical areas that enclose them as sieve areas. The phloem of E. leclercqii and B. tridentata is compared with that described for other fossil genera and with that of extant ferns.     

Bacterial cell surface structures involved in lucerne cell wall degradation by pure cultures of cellulolytic rumen bacteria

Summary Pure cultures of the cellulolytic rumen bacterial strains Bacteroides succinogenes S85, Ruminococcus flavefaciens FD1 and Ruminococcus albus 7 were grown on lucerne cell walls (CW) or on cellobiose as the sole added carbohydrate substrate. Scanning electron microscopy visualization using cationized-feritin pretreatment have shown that cell surface topology of these strains grown on and attached to CW particles was specified by a dense coat of characteristic protuberant structures. In contrast, when grown on cellobiose, the surface topology of these bacterial strains was smoother, and contained fewer protuberant structures. The ability of these bacterial strains to attach to cellulose was higher for bacteria previously adapted to lucerne CW compared to cellobiose adaptation. Bacteroides succinogenes S85 was the best digester of lucerne CW (46.5%) and also had the best adhesion capability (65.6%) after adaption to grow on CW.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 2599-E, 1989 seriesOffprint requests to: J. Miron     

Sieve elements rapidly develop ‘nacreous walls’ following injury − a common wounding response?

Thick glistening cell walls occur in sieve tubes of all major land plant taxa. Historically, these ‘nacreous walls’ have been considered a diagnostic feature of sieve elements; they represent a conundrum, though, in the context of the widely accepted pressure–flow theory as they severely constrict sieve tubes. We employed the cucurbit Gerrardanthus macrorhizus as a model to study nacreous walls in sieve elements by standard and in situ confocal microscopy and electron microscopy, focusing on changes in functional sieve tubes that occur when prepared for microscopic observation. Over 90% of sieve elements in tissue sections processed for microscopy by standard methods exhibit nacreous walls. Sieve elements in whole, live plants that were actively transporting as shown by phloem‐mobile tracers, lacked nacreous walls and exhibited open lumina of circular cross‐sections instead, an appropriate structure for Münch‐type mass flow of the cell contents. Puncturing of transporting sieve elements with micropipettes triggered the rapid (<1 min) development of nacreous walls that occluded the cell lumen almost completely. We conclude that nacreous walls are preparation artefacts rather than structural features of transporting sieve elements. Nacreous walls in land plants resemble the reversibly swellable walls found in various algae, suggesting that they may function in turgor buffering, the amelioration of osmotic stress, wounding‐induced sieve tube occlusion, and possibly local defence responses of the phloem.     

Penetration Behaviour of Venturia nashicola,Associated with Hydrogen Peroxide Generation,in Asian and European Pear Leaves

The penetration behaviour of the pathogen Venturia nashicola, which causes scab disease in Asian pears, was studied at the ultrastructural and cytochemical levels in host and non‐host leaves. We show, for the first time, that before V. nashicola penetrated the cuticle of the epidermis of the pear leaf, the appressorial bottom of the pathogen invaginated to form a cavity that contains electron‐dense material. The leaf cuticle beneath the cavity also became highly electron dense following penetration by V. nashicola. The location of these electron‐dense materials at the sites of penetration of the pathogen into plant cell walls suggests that they might be related to enzymes capable of degrading cell walls and that the cavities might be needed for successful penetration of leaves by V. nashicola. The generation of hydrogen peroxide (H₂O₂) was observed in penetration‐related infection structures of V. nashicola, such as appressorial bottoms, infection sacs, penetration pegs and necks of subcuticular hyphae regardless of whether the interaction of V. nashicola with pear plants was compatible or incompatible. Nonetheless, more H₂O₂ was generated at the sites of the structures in scab‐inoculated susceptible leaves than that in scab‐inoculated resistant ones. Furthermore, the decrease in the level of H₂O₂ generation following treatment with the antioxidant ascorbic acid partially prevented the penetration of the cuticle. Therefore, the generation of H₂O₂ from the penetration‐related structures might be a pathogenicity factor that contributes to strengthening the penetration peg of V. nashicola.     

Composition of the cell wall of Chlorella fusca

Isolated cell walls of mature Chlorella fusca consisted of about 80% carbohydrate, 7% protein, and 13% unidentified material. Mannose and glucose were present in a ratio of about 2.7:1 and accounted for most of the carbohydrate. Minor components were glucuronic acid, rhamnose, and traces of other sugars; galactose was absent. After treatment with 2 M trifluoroacetic acid or with 80% acetic acid/HNO₃ (10/1, v/v), a residue with a mannose/glucose ratio of 0.3:1 was obtained, probably representing a structural polysaccharide. An X-ray diffraction diagram of the walls showed one diffuse reflection at 0.44 nm and no reflections characteristic of cellulose. Walls from young cells contained about 51% carbohydrate, 12% protein, and 37% unidentified material. Mannose and glucose were also the main sugars; their absolute amounts per wall increased 6–7 fold during cell growth. Walls isolated with omission of a dodecylsulphate/mercaptoethanol/urea extraction step had a higher protein content and, with young walls, a significantly higher glucose and fucose content. These data and other published cell wall analyses show a wide variability in cell wall composition of the members of the genus Chlorella.Abbreviations GLC gas liquid chromatography - TFA trifluoroacetic acid