Nutrient uptake byCandida albicans: the influence of cell surface mannoproteins

1999 ◽  
Vol 45 (5) ◽  
pp. 353-359 ◽  
Author(s):  
Phyllis C Braun
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Candida Albicans ◽  
Aspartic Acid ◽  
Intracellular Transport ◽  
Strain Differences ◽  
Dry Weight ◽  
Culture Conditions ◽  
Wall Structure ◽  
Biochemical Analyses

Numerous ultrastructural and biochemical analyses have been performed to characterize the cell wall composition and structure of Candida albicans. However, little investigation has focused on how subtle differences in cell wall structure influence the intracellular transport of amino acids and monosaccharides. In this study C. albicans 4918 and ATCC 10231 were grown in culture conditions capable of modifying surface mannoproteins and induced surface hydrophobic or hydrophilic yeast cell wall states. Subcultures of these hydrophobic and hydrophilic yeasts were subsequently incubated with one of seven L-[3H] amino acids: glycine, leucine, proline, serine, aspartic acid, lysine, or arginine. The transport of [3H] mannose and [3H] N-acetyl-D-glucosamine were also investigated. This study revealed significant strain differences (P [Formula: see text] 0.05) between hydrophilic and hydrophobic yeast transport of these nutrients throughout a 2 h incubation. Hydrophilic cultures of 4918 and ATCC 10231 transported nearly two times more (pmol mg-1dry weight) proline, mannose, and N-acetyl-D-glucosamine than hydrophobic yeast. Hydrophobic cultures preferentially incorporated serine and aspartic acid in both these strains. Strain variation was indicated with the transport of leucine, lysine, and arginine, as follows: experiments showed that hydrophilic 4918 cultures selectively transported leucine, lysine, and arginine, whereas, the hydrophobic ATCC 10231 cultures incorporated these amino acids.Key words: Candida albicans, mannoproteins, amino acid transport.

scholarly journals Role of the Candida albicans MNN1 gene family in cell wall structure and virulence

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Steven Bates ◽  
Rebecca A Hall ◽  
Jill Cheetham ◽  
Mihai G Netea ◽  
Donna M MacCallum ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Gene Family ◽  
Cell Wall Structure ◽  
Wall Structure

Fine structure in the red algae - II. The structure of the cell wall of Rhodymenia Palmata

1959 ◽  
Vol 150 (941) ◽  
pp. 447-455 ◽  
Keyword(s):  
Cell Wall ◽  
Chemical Treatment ◽  
Amorphous Matrix ◽  
Dry Weight ◽  
Wall Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Floridean Starch ◽  
Thin Sectioning ◽  
Paper Chromatographic Separation

The cell-wall structure of the red alga Rhodymenia palmata has been examined by the methods of X -ray diffraction analysis and electron microscopy, including ultra-thin sectioning. The cell wall is shown to consist of numerous lamellae each of which is made up of unoriented, crystalline microfibrils embedded in an amorphous matrix of other cell-wall constituents. The material can be stretched reversibly up to 100% when wet, and the stretching induces orientation of the microfibrils. The ‘∝ cellulose' fraction, which accounts for only 2 to 7 % of the original dry weight, was isolated chemically and was analyzed by means of hydrolysis and paper chromatographic separation of the resulting sugars, and it was found to be composed of approximately equal quantities of glucose and xylose residues. Chemical treatment of the cell wall was found to cause considerable variations in the X -ray diagrams, which are discussed. It is concluded that the microfibrils contain both glucose and xylose residues in approximately equal proportions and that chemical treatment in this case causes changes in crystallinity of the structural component of the wall. The importance of these findings for the meaning of the term cellulose is discussed. The X -ray diagram of older fronds was found to be complicated by the occurrence of extra rings due to the presence of floridean starch, and the highly elastic properties of the thallus enabled the diagrams of the starch and the cell wall to be separated.

Nutritional requirements for cell wall synthesis in Micrococcus lysodeikticus

1969 ◽  
Vol 15 (4) ◽  
pp. 327-334
Author(s):  
M. P. Hatton
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Glutamic Acid ◽  
Dry Weight ◽  
Defined Medium ◽  
Complete Medium ◽  
Magnesium Ions ◽  
Cell Wall Synthesis ◽  
Micrococcus Lysodeikticus ◽  
Total Dry Weight

Preferential cell wall synthesis in Micrococcus lysodeikticus, as determined by an increase in the dry weight of the cell wall, took place in a medium containing DL-glutamic acid, DL-alanine, L-lysine, glycine, magnesium ions, glucose and phosphate buffer, pH 7.0. Cell wall synthesis could not be completely dissociated from protein synthesis in the 'cell wall' medium. The cell wall synthesized in the defined medium accounted for 40–56% of the total dry weight increase of the cells. Chloramphenicol had no effect on cell wall synthesis. Incorporation of uracil and guanine in the medium did not result in any increase in the amount of cell wall synthesized. DL-Glutamic acid alone, or a mixture of the three amino acids DL-alanine, L-lysine, and glycine, were capable of replacing the four amino acids present in the complete medium, but under these conditions the total dry weight of cell wall synthesized was only 75% of that produced in the complete medium. There was no reduction in cell wall synthesis when L-glutamic acid replaced DL-glutamic acid, L-alanine replaced DL-alanine, or sucrose replaced glucose in the cell wall medium. Deprivation of magnesium ions produced the greatest decrease in wall synthesis; this was the most important single factor involved in cell wall synthesis which was studied in the present investigation. There was no observable change in the chemical composition of the cell wall synthesized in the 'wall' medium when compared to that synthesized by cells grown in a complex medium.

scholarly journals Multiple Alternative Carbon Pathways Combine To Promote Candida albicans Stress Resistance, Immune Interactions, and Virulence

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert B. Williams ◽  
Michael C. Lorenz
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Candida Albicans ◽  
Stress Resistance ◽  
Innate Immune System ◽  
Carbon Sources ◽  
Innate Immune ◽  
Content Type ◽  
Multiple Alternative ◽  
Carbon Pathways

ABSTRACT The phagocytic cells of the innate immune system are an essential first line of antimicrobial defense, and yet Candida albicans, one of the most problematic fungal pathogens, is capable of resisting the stresses imposed by the macrophage phagosome, eventually resulting in the destruction of the phagocyte. C. albicans rapidly adapts to the phagosome by upregulating multiple alternative carbon utilization pathways, particularly those for amino acids, carboxylic acids, and N-acetylglucosamine (GlcNAc). Here, we report that C. albicans recognizes these carbon sources both as crucial nutrients and as independent signals in its environment. Even in the presence of glucose, each carbon source promotes increased resistance to a unique profile of stressors; lactate promotes increased resistance to osmotic and cell wall stresses, amino acids increased resistance to oxidative and nitrosative stresses, and GlcNAc increased resistance to oxidative stress and caspofungin, while all three alternative carbon sources have been shown to induce resistance to fluconazole. Moreover, we show mutants incapable of utilizing these carbon sources, in particular, strains engineered to be defective in all three pathways, are significantly attenuated in both macrophage and mouse models, with additive effects observed as multiple carbon pathways are eliminated, suggesting that C. albicans simultaneously utilizes multiple carbon sources within the macrophage phagosome and during disseminated candidiasis. Taking the data together, we propose that, in addition to providing energy to the pathogen within host environments, alternative carbon sources serve as niche-specific priming signals that allow C. albicans to recognize microenvironments within the host and to prepare for stresses associated with that niche, thus promoting host adaptation and virulence. IMPORTANCE Candida albicans is a fungal pathogen and a significant cause of morbidity and mortality, particularly in people with defects, sometimes minor ones, in innate immunity. The phagocytes of the innate immune system, particularly macrophages and neutrophils, generally restrict this organism to its normal commensal niches, but C. albicans shows a robust and multifaceted response to these cell types. Inside macrophages, a key component of this response is the activation of multiple pathways for the utilization of alternative carbon sources, particularly amino acids, carboxylic acids, and N-acetylglucosamine. These carbon sources are key sources of energy and biomass but also independently promote stress resistance, induce cell wall alterations, and affect C. albicans interactions with macrophages. Engineered strains incapable of utilizing these alternative carbon pathways are attenuated in infection models. These data suggest that C. albicans recognizes nutrient composition as an indicator of specific host environments and tailors its responses accordingly.

SYNTHESIS OF MACROMOLECULES IN MAIZE ROOT TIPS

1967 ◽  
Vol 45 (4) ◽  
pp. 385-394 ◽  
Author(s):  
Ann Oaks
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Continuous Flow ◽  
Flow System ◽  
Dry Weight ◽  
Maximal Rate ◽  
Root Tips ◽  
Corn Roots ◽  
Rate Of Increase ◽  
Cell Wall Carbohydrates

Corn roots grown in a glucose–salts medium in a continuous flow system suffered an initial loss of protein before an increase was observed. A maximal rate of increase in cell-wall carbohydrates was achieved after 20 hours in culture. There was some loss in RNA while the increase in DNA was slight. A synthetic mixture of 15 L-amino acids enhanced the growth (defined as increase in length, dry weight, or alcohol-insoluble nitrogen) of glucose-grown roots. With this enriched medium there was a slight increase of protein over the initial 20-hour period and a faster rate of increase after this time. No lag in the increase in cell-wall carbohydrates was observed. Despite these symptoms of better growth the level of DNA was not improved by the addition of the amino acids and the RNA content was actually lower than in the glucose-grown roots. Although the level of RNA was less in cultured than in normal roots, ribosomal and soluble RNA accounted for similar proportions of the total RNA in each case.

scholarly journals The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

Microbiology ◽  
2009 ◽  
Vol 155 (6) ◽  
pp. 2004-2020 ◽  
Author(s):  
Emilia Moreno-Ruiz ◽  
Giuseppe Ortu ◽  
Piet W. J. de Groot ◽  
Fabien Cottier ◽  
Céline Loussert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Fungal Pathogens ◽  
High Sensitivity ◽  
Wall Structure ◽  
Minor Role ◽  
Cell Wall Proteins ◽  
Calcofluor White ◽  
Fungal Cell ◽  
A Minor

The fungal cell wall is essential in maintaining cellular integrity and plays key roles in the interplay between fungal pathogens and their hosts. The PGA59 and PGA62 genes encode two short and related glycosylphosphatidylinositol-anchored cell wall proteins and their expression has been previously shown to be strongly upregulated when the human pathogen Candida albicans grows as biofilms. Using GFP fusion proteins, we have shown that Pga59 and Pga62 are cell-wall-located, N- and O-glycosylated proteins. The characterization of C. albicans pga59Δ/pga59Δ, pga62Δ/pga62Δ and pga59Δ/pga59Δ pga62Δ/pga62Δ mutants suggested a minor role of these two proteins in hyphal morphogenesis and that they are not critical to biofilm formation. Importantly, the sensitivity to different cell-wall-perturbing agents was altered in these mutants. In particular, simultaneous inactivation of PGA59 and PGA62 resulted in high sensitivity to Calcofluor white, Congo red and nikkomicin Z and in resistance to caspofungin. Furthermore, cell wall composition and observation by transmission electron microscopy indicated an altered cell wall structure in the mutant strains. Collectively, these data suggest that the cell wall proteins Pga59 and Pga62 contribute to cell wall stability and structure.

scholarly journals Serologic Response to Cell Wall Mannoproteins and Proteins of Candida albicans

1998 ◽  
Vol 11 (1) ◽  
pp. 121-141 ◽  
Author(s):  
José P. Martínez ◽  
M. Luisa Gil ◽  
José L. López-Ribot ◽  
W. LaJean Chaffin
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antibody Response ◽  
Humoral Response ◽  
Binding Activity ◽  
Cell Wall Protein ◽  
Wall Structure ◽  
Cell Mediated Immunity ◽  
Host Immune System

SUMMARY The cell wall of Candida albicans not only is the structure in which many biological functions essential for the fungal cells reside but also is a significant source of candidal antigens. The major cell wall components that elicit a response from the host immune system are proteins and glycoproteins, the latter being predominantly mannoproteins. Both the carbohydrate and protein moieties are able to trigger immune responses. Although cell-mediated immunity is often considered to be the most important line of defense against candidiasis, cell wall protein and glycoprotein components also elicit a potent humoral response from the host that may include some protective antibodies. Proteins and glycoproteins exposed at the most external layers of the wall structure are involved in several types of interactions of fungal cells with the exocellular environment. Thus, coating of fungal cells with host antibodies has the potential to influence profoundly the host-parasite interaction by affecting antibody-mediated functions such as opsonin-enhanced phagocytosis and blocking the binding activity of fungal adhesins for host ligands. In this review, the various members of the protein and glycoprotein fraction of the C. albicans cell wall that elicit an antibody response in vivo are examined. Although a number of proteins have been shown to stimulate an antibody response, for some of these species the response is not universal. On the other hand, some of the studies demonstrate that certain cell wall antigens and anti-cell wall antibodies may be the basis for developing specific and sensitive serologic tests for the diagnosis of candidasis, particularly the disseminated form. In addition, recent studies have focused on the potential for antibodies to cell wall protein determinants to protect the host against infection. Hence, a better understanding of the humoral response to cell wall antigens of C. albicans may provide the basis for the development of (i) effective procedures for the serodiagnosis of disseminated candidiasis and (ii) novel prophylactic (vaccination) and therapeutic strategies for the management of this type of infection.

Composition and properties of the cell wall of Methanospirillum hungatii

1980 ◽  
Vol 26 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G. D. Sprott ◽  
R. C. McKellar
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Cell Walls ◽  
Weight Fraction ◽  
Dry Weight ◽  
Wall Material ◽  
Bond Breaking ◽  
High Molecular Weight Fraction ◽  
Cell Wall Proteins ◽  
Isolated Cell

Dithiothreitol reacted, at pH 9.0, with the isolated cell walls of Methanospirillum hungatii, to release about 23% of the cell wall dry weight as a high molecular weight fraction (> 0.5 million daltons). Untreated walls consisted of 70% amino acids, 11% lipid, and 6.6% carbohydrate. Sugars were identified as rhamnose, ribose, glucose, galactose, and mannose. The wall material that was released contained only 47% amino acids and was enriched in lipid, glucose, and phosphate. These results support data from electron micrographs, showing the localized release of cell wall material by the disulfide bond-breaking reagent at alkaline pH. In amino acid composition the untreated walls did not differ greatly from the material released by dithiothreitol, but differed considerably from the walls of another strain of M. hungatii. The ratios of the amino acids found in the cell wall proteins of several archaebacteria and of Bacillus cereus spore coats were similar.

scholarly journals The structure of a glycopeptide isolated from the yeast cell wall

1968 ◽  
Vol 109 (3) ◽  
pp. 419-432 ◽  
Author(s):  
R. Sentandreu ◽  
D. H. Northcote
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Cell Wall ◽  
Amino Acid ◽  
Yeast Cell ◽  
Aspartic Acid ◽  
Yeast Cell Wall ◽  
Low Molecular Weight ◽  
Elimination Reaction ◽  
Sephadex Column

1. Glycopeptides containing mannose were extracted from isolated yeast cell walls by ethylenediamine and purified by treatment with Pronase and fractionation on a Sephadex column. 2. A glycopeptide that appeared homogeneous on electrophoresis and ultracentrifugation had a molecular weight of 76000, and contained a high-molecular-weight mannan and approx. 4% of amino acids. 3. The amino acid composition of the peptide was determined. It was rich in serine and threonine and also contained glucosamine. No cystine and methionine were detected. 4. The glycopeptide underwent a β-elimination reaction when treated with dilute alkali at low temperatures. The reaction resulted in the release of mannose, mannose disaccharides and possibly other low-molecular-weight mannose oligosaccharides. During the β-elimination reaction the dehydro derivatives of serine and threonine were formed. One of the linkages between carbohydrate and amino acids in the glycopeptide is an O-mannosyl bond from mannose and mannose oligosaccharides to serine and threonine. 5. After the β-elimination reaction the bulk of the mannose in the form of the large mannan component was still covalently linked to the peptide. This polysaccharide was therefore attached to the amino acids by a linkage different from the O-mannosyl bonds to serine and threonine that attach the low-molecular-weight sugars. 6. Mannan was prepared from the glycopeptide and from the yeast cell wall by treatment of the fractions with hot solutions of alkali. The mannan contained aspartic acid and glucosamine and some other amino acids. The aspartic acid and glucosamine were present in equimolar amounts; the aspartic acid was the only amino acid present in an amount equivalent to that of glucosamine. Thus there is the possibility of a linkage between the mannan and the peptide via glucosamine and aspartic acid. 7. Mannose 6-phosphate was shown to be part of the mannan structure. Information about the structure of the mannan and the linkage of the glucosamine was obtained by periodate oxidation studies. 8. The glucosamine present in the glycopeptide could not be released by treatment with an enzyme preparation obtained from the gut of Helix pomatia. This enzyme released glucosamine from the intact cell wall. Thus there are probably at least two polymers containing glucosamine in the cell wall. 9. The biosynthesis of the mannan polymer in the yeast cell wall is discussed with regard to the two types of carbohydrate–amino acid linkages found in the glycoprotein.

scholarly journals Differences in huperzine A yield when different amino acids were added for in vitro thallus culture of Huperzia serrata (Thunb)Trev and gene expression analysis

2020 ◽  
Author(s):  
Ye YuXuan ◽  
Tu YiSheng ◽  
Yu Xiao ◽  
Huang Qian ◽  
Yuan Huihui
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Aspartic Acid ◽  
Quantitative Pcr ◽  
Dry Weight ◽  
Huperzine A ◽  
Differential Analysis ◽  
Fluorescence Quantitative Pcr ◽  
Alignment Analysis

Abstract Background：the secondary metabolite of H. serrata, huperzine A (HupA) can be used in the treatment of Alzheimer’s disease and can improve the cognitive function of patients. The use of in vitro culture and secondary metabolism engineering to obtain secondary metabolites is the most effective method to solve a lack of HupA sources and protect H. serrata as a natural resource. This study was based on the in vitro thallus culture conditions for H. serrate, and different concentrations of alkaloid precursor amino acids (lysine, aspartic acid, and trytophan) were added. We found that addition of different amino acids to thallus cultures had different effects on HupA accumulation. Transcriptome sequencing was carried out on thalli with significant differences in the HupA content due to treatment with different amino acids for differential analysis, and real-time fluorescence quantitative PCR was used for validation to examine the functional genes involved in exogenous amino acid regulation of HupA accumulation in thalli.Results：We found that addition of 1 mmol·L−1 aspartic acid (D) solution promoted HupA accumulation, at a level of 84.05 μg·g−1 dry weight (DW), which was 1.29-fold that of the control (CK: 65.15 μg·g−1 DW). Addition of 4 mmol·L−1 lysine (K) solution significantly inhibited HupA accumulation, at a level of 48.42 μg·g−1 DW, which was 0.75-fold that of the control.Transcriptome sequencing-bioinformatics alignment analysis of the aforementioned materials showed that in GO alignment analysis, functions were annotated for 16,258 unigenes. From the statistical analysis of the DEGs of the three groups, we found that there were 1046, 782, and 1586 DEGs for CK vs D, CK vs K, and D vs K, respectively, with D vs K having the most DEGs. DEGs that were enriched in KEGG metabolic pathways and validated by fluorescence quantitative PCR included PANK1, GDH2, APX, HA1, ND4L, and COX1. Conclusions：The above results showed that HupA content differences in D and K treatments were directly proportional to DEGs. Gene expression differences are the molecular basis that affects HupA accumulation in in vitro thallus cultures. PANK1 and GDH2 encode enzymes that synthesize an alkaloid intermediate.

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