The effects of elevated temperatures on spore swelling and germination in Aspergillus niger

1972 ◽  
Vol 18 (3) ◽  
pp. 289-297 ◽  
Author(s):  
J. G. Anderson ◽  
J. E. Smith
Keyword(s):  
Aspergillus Niger ◽  
Germ Tube ◽  
Elevated Temperatures ◽  
Nitrogen Sources ◽  
Tube Formation ◽  
Carbon And Nitrogen ◽  
Gaseous Environment ◽  
Spherical Cells ◽  
Spherical Growth ◽  
Germ Tubes

Exogenous carbon and nitrogen sources were necessary for complete swelling (spherical growth) and germ-tube formation from Aspergillus niger spores. The rate of spherical growth was low at 30°, maximum at 38°, and decreased at higher temperatures until at 47° inhibition was complete. At temperatures from 35° to 44° the final spore size was similar and greater than at 30° although the time taken to reach this size varied. Germ-tube formation occurred in from 97 to 99% of the spores with a good degree of synchrony between 30° and 38°. At temperatures from 38° to 43° the proportion of spores which produced germ tubes gradually decreased with a concurrent loss of synchrony. At 44° germ-tube formation was completely inhibited although spherical growth could occur over a prolonged period to produce large spherical cells. This increase of cell volume was apparently accompanied by a system of wall extension which involved wall synthesis. Under conditions of spore crowding an inhibition became apparent which affected only the initiation of spherical growth and not the spherical-growth process itself. Other effects of spore crowding were observed and were attributed to alterations in the gaseous environment. Increased spherical growth was always accompanied by a greater degree of branching of the germ tube when produced and a hypothesis relating these effects is suggested.

Carbon dioxide induces endotrophic germ tube formation in Candida albicans

1990 ◽  
Vol 36 (4) ◽  
pp. 249-253 ◽  
Author(s):  
Ruth C. Mock ◽  
Jordan H. Pollack ◽  
Tadayo Hashimoto
Keyword(s):  
Carbon Dioxide ◽  
Candida Albicans ◽  
Sodium Bicarbonate ◽  
Key Words ◽  
Germ Tube ◽  
Tube Formation ◽  
Chemical Inducers ◽  
Tube Emergence ◽  
Ph Range ◽  
Germ Tubes

Candida albicans formed germ tubes when exposed to air containing 5 to 15% carbon dioxide (CO2). The CO2-mediated germ tube formation occurred optimally at 37 °C in a pH range of 5.5 to 6.5. No germ tubes were produced at 25 °C, even when the optimal concentration of CO2 (10%) was present in the environment. The requirement of CO2 for germ tube formation could be partially substituted by sodium bicarbonate but not by N2. Carbon dioxide was required to be present throughout the entire course of germ tube emergence suggesting that its role is not limited to an initial triggering of morphogenic change. We suggest that carbon dioxide may be a common effector responsible for the germ tube promoting activity of certain chemical inducers for C. albicans. Key words: Candida albican germ tubes, CO2-induced germ tube formation, endotrophic germ tube formation.

scholarly journals Evaluation of agricultural byproducts for the production of betaglucosidase by Aspergillus niger MBT-2 using solid state fermentation

2020 ◽  
Vol 49 (1) ◽  
pp. 135-140
Author(s):  
Roheena Abdullah ◽  
Maria Hanif ◽  
Afshan Kaleem ◽  
Mehwish Iqtedar ◽  
Kinza Nisar ◽  
...  
Keyword(s):  
Solid State ◽  
Aspergillus Niger ◽  
Solid State Fermentation ◽  
Low Cost ◽  
Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Enhanced Production ◽  
Enzyme Productivity ◽  
Valuable Product ◽  
By Products

The experiment was conducted to isolate and screen fungal strain and optimization of solid-state fermentation conditions for enhanced production of β-glucosidase. Different fungal cultures were isolated and screened for β-glucosidase production. The physicochemical and nutritional parameters were optimized for enhanced production of β-glucosidase from higher producer. Among all the isolates the isolate which exhibited highest β-glucosidase potential was identified and assigned the code as Aspergillus niger MBT-2. The optimum β-glucosidase production was obtained in M5 medium containing wheat bran after 72 hrs of incubation at 40°C, pH 6 and 20 ml of moisture contents. In addition to this 2% fructose and 2% yeast extract proved to be best carbon and nitrogen sources, respectively and gave maximal enzyme productivity. The exploitation of agricultural by products as a substrate reduced the production cost of enzyme and makes the process economical. The Aspergillus niger MBT-2 has promising potential of bioconversion of low-cost material into valuable product like β-glucosidase.

Germ-tube production by Candida albicans in minimal liquid culture media

1971 ◽  
Vol 17 (7) ◽  
pp. 851-856 ◽  
Author(s):  
D. N. Mardon ◽  
I. S. K. Hurst ◽  
E. Balish
Keyword(s):  
Candida Albicans ◽  
Butyric Acid ◽  
Germ Tube ◽  
Culture Medium ◽  
Culture Media ◽  
Tube Formation ◽  
Gamma Amino Butyric Acid ◽  
Tube Production ◽  
Amino Butyric Acid ◽  
Germ Tubes

Candida albicans formed germ tubes within 3 h at 37C in a glucose–salts–biotin (GSB) medium containing L-alpha-amino-n-butyric acid as the nitrogen source. Optimal germ-tube production was obtained when the inoculum was grown on Sabouraud dextrose agar. The GSB medium containing L-alpha-amino-n-butyric acid promoted germ-tube formation more effectively than GSB medium plus gamma-amino-butyric acid or Sabouraud dextrose broth.Carbon-14 incorporation studies revealed that during germ-tube formation (0–4 h) the 3 carbon of alpha-amino-n-butyric acid was incorporated intracellularly to a greater extent than the 1 carbon. However, during blastospore formation (5–16 h), this difference was less pronounced.When six other Candida species were grown in GSB plus L-alpha-amino-n-butyric acid medium, few germ tubes were observed with the exception of one Candida stellatoidea strain. However, even this strain of C. stellatoidea produced far fewer germ tubes in this minimal culture medium than any strain of C. albicans tested.

scholarly journals Arginine-Induced Germ Tube Formation in Candida albicans Is Essential for Escape from Murine Macrophage Line RAW 264.7

2009 ◽  
Vol 77 (4) ◽  
pp. 1596-1605 ◽  
Author(s):  
Suman Ghosh ◽  
Dhammika H. M. L. P. Navarathna ◽  
David D. Roberts ◽  
Jake T. Cooper ◽  
Audrey L. Atkin ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogen ◽  
Germ Tube ◽  
Tube Formation ◽  
Raw 264.7 ◽  
Dependent Manner ◽  
Wild Type ◽  
Normal Flora ◽  
Opportunistic Fungal Pathogen ◽  
Germ Tubes

ABSTRACT The opportunistic fungal pathogen Candida albicans is a part of the normal flora but it also causes systemic candidiasis if it reaches the bloodstream. Upon being phagocytized by macrophages, an important component of innate immunity, C. albicans rapidly upregulates a set of arginine biosynthetic genes. Arginine, urea, and CO2 induced hyphae in a density-dependent manner in wild-type, cph1/cph1, and rim101/rim101 strains but not in efg1/efg1 or cph1/cph1 efg1/efg1 strains. Arginase (Car1p) converts arginine to urea, which in turn is degraded by urea amidolyase (Dur1,2p) to produce CO2, a signal for hyphal switching. We used a dur1,2/dur1,2 mutant (KWN6) and the complemented strain, KWN8 (dur1,2/dur1,2::DUR1,2/DUR1,2) to study germ tube formation. KWN6 could not make germ tubes in the presence of arginine or urea but did in the presence of 5% CO2, which bypasses Dur1,2p. We also tested the effect of arginine on the interaction between the macrophage line RAW 264.7 and several strains of C. albicans. Arginine activated an Efg1p-dependent yeast-to-hypha switch, enabling wild-type C. albicans and KWN8 to escape from macrophages within 6 h, whereas KWN6 was defective in this regard. Additionally, two mutants that cannot synthesize arginine, BWP17 and SN152, were defective in making hyphae inside the macrophages, whereas the corresponding arginine prototrophs, DAY286 and SN87, formed germ tubes and escaped from macrophages. Therefore, metabolism of arginine by C. albicans controls hyphal switching and provides an important mechanism for escaping host defense.

scholarly journals Experimental Germ Tube Induction in Candida albicans: An Evaluation of the Effect of Sodium Bicarbonate on Morphogenesis and Comparison with Pooled Human Serum

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Tapiwa Matare ◽  
Pasipanodya Nziramasanga ◽  
Lovemore Gwanzura ◽  
Valerie Robertson
Keyword(s):  
Candida Albicans ◽  
Human Serum ◽  
Germ Tube ◽  
Tube Formation ◽  
Joint Research ◽  
Significant Difference ◽  
Buffer Control ◽  
Tris Maleate ◽  
Microscope Slides ◽  
Germ Tubes

Objective. The potential of NaHCO3 versus human serum to induce germ tube formation in Candida albicans was investigated. Specimens. A total of 100 isolates were obtained from oral swabs of patients presenting with thrush. Approval for the study was granted by the Joint Research Ethics Committee (JREC/23/08). Method. Confirmed C. albicans isolates by routine methods were tested for germ tube induction using 5 different concentrations of Tris-maleate buffered NaHCO3 and Tris-maleate buffer control. Standard control strains included were C. albicans (ATCC 10231) and C. krusei (ATCC 6258). Microculture was done in 20 μL inoculums on microscope slides for 3 hours at 37°C. The rate of germ tube formation at 10-minute intervals was determined on 100 isolates using the optimum 20 mM Tris-maleate buffered NaHCO3 concentration. Parallel germ tube formation using human serum was done in test tubes. Results. The optimum concentration of NaHCO3 in Tris-maleate buffer for germ tube induction was 20 mM for 67% of isolates. Only 21% of isolates formed germ tubes in Tris-maleate buffer control. There was no significant difference in induction between human serum and Tris-maleate buffered NaHCO3. Conclusion. Tris-maleate buffered NaHCO3 induced germ tube formation in C. albicans isolates at rates similar to human serum.

Identification of the dialysable serum inducer of germ-tube formation in Candida albicans

Microbiology ◽  
2004 ◽  
Vol 150 (9) ◽  
pp. 3041-3049 ◽  
Author(s):  
Debbie A. Hudson ◽  
Quentin L. Sciascia ◽  
Rebecca J. Sanders ◽  
Gillian E. Norris ◽  
Pat J. B. Edwards ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Active Component ◽  
Germ Tube ◽  
Nitrogen Sources ◽  
Hyphal Growth ◽  
Tube Formation ◽  
Size Exclusion ◽  
Yeast Cells ◽  
Induction Medium ◽  
Ph Optimum

Yeast cells of Candida albicans are induced by serum at 37 °C to produce germ tubes, the first step in a transition from yeast to hyphal growth. Previously, it has been shown that the active component is not serum albumin but is present in the dialysable fraction of serum. In this study, serum induction of germ-tube formation is shown to occur even in the presence of added exogenous nitrogen sources and is therefore not signalled by nitrogen derepression. The active component in serum was purified by ion-exchange, reverse-phase and size-exclusion chromatography from the dialysable fraction of serum and was identified by NMR to be d-glucose. Enzymic destruction of glucose, using glucose oxidase, demonstrated that d-glucose was the only active component in these fractions. Induction of germ-tube formation by d-glucose required a temperature of 37 °C and the pH optimum was between pH 7·0 and 8·0. d-Glucose induced germ-tube formation in a panel of clinical isolates of C. albicans. Although d-glucose is the major inducer in serum, a second non-dialysable, trichloroacetic acid precipitable inducer is also present. However, whereas either 1·4 % (v/v) serum or an equivalent concentration of d-glucose induced 50 % germ-tube formation, the non-dialysable component required a 10-fold higher concentration to induce 50 % germ-tube formation. Serum is, therefore, the most effective induction medium for germ-tube formation because it is buffered at about pH 8·5 and contains two distinct inducers (glucose and a non-dialysable component), both active at this pH.

Investigations of Entomophthora muscae (Cohn) (Entomophthorales: Entomophthoraceae) conidial infection on housefly Musca domestica (Linn.) by scanning electron microscopy

1993 ◽  
Vol 39 (4) ◽  
pp. 363-366
Author(s):  
C. M. Tu ◽  
B. L. Singh
Keyword(s):  
Electron Microscopy ◽  
Germ Tube ◽  
Tube Formation ◽  
Insect Cuticle ◽  
Entomophthora Muscae ◽  
Entomogenous Fungus ◽  
Insect Pathology ◽  
Germ Tubes ◽  
Infection Cushion ◽  
Scanning Electron

An entomogenous fungus, Entomophthora muscae, was studied morphologically with respect to the formation of primary and secondary conidia and germ tubes. The fungus penetrated the insect cuticle by germ tubes that were produced at the base of each conidium that penetrated directly through the cuticle. Fungal germ-tube formation and penetration of host integument were observed. The tough germ-tube penetration point seemed to provide abundant energy for the penetration of the host integument. Conidia not directly on the integument formed secondary conidia but were never observed to form germ tubes. Neither appressorium nor infection cushion was observed on the germ tubes.Key words: Entomophthora muscae, entomogenous fungus, insect mycosis, insect pathology, conidia.

Effect of Carbon and Nitrogen Sources on Xylanase Production by Mutant Strain of Aspergillus niger GCBMX-45

2002 ◽  
Vol 2 (2) ◽  
pp. 143-144 ◽  
Author(s):  
Ikram-ul-Haq . ◽  
Ayesha Khan . ◽  
Waseem Ahmad Butt . ◽  
Sikander Ali . ◽  
M. A. Qadeer .
Keyword(s):  
Aspergillus Niger ◽  
Mutant Strain ◽  
Nitrogen Sources ◽  
Carbon And Nitrogen Sources ◽  
Xylanase Production ◽  
Carbon And Nitrogen

Induction of germ tube formation by N-acetyl-D-glucosamine in Candida albicans: uptake of inducer and germinative response

1982 ◽  
Vol 152 (2) ◽  
pp. 555-562
Author(s):  
E Mattia ◽  
G Carruba ◽  
L Angiolella ◽  
A Cassone
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Insoluble Fraction ◽  
Tube Formation ◽  
Uranyl Acetate ◽  
Uptake System ◽  
Low Responders ◽  
Cell Fractions ◽  
Germ Tubes ◽  
High Responders

A number of strains of Candida albicans were tested for germ tube formation after induction by N-acetyl-D-glucosamine (GlcNAc) and other simple (proline, glucose plus glutamine) or complex (serum) compounds. A proportion of strains (high responders) were induced to form germ tubes evolving to true hyphae by GlcNAc alone or by proline or glucose plus glutamine mixture. The majority of strains were low responders because they could be induced only by serum or GlcNAc-serum medium. Two strains were found to be nonresponders: they grew as pseudohyphae in serum. Despite minor quantitative differences, all strains efficiently utilized GlcNAc for growth under the yeast form at 28 degrees C. They also had comparable active, inducible, and constitutive uptake systems for GlcNAc. During germ tube formation in GlcNAc, the inducible uptake system was modulated, as expected from induction and decay of GlcNAc kinase. Uranyl acetate, at a concentration of 0.01 mM, inhibited both GlcNAc uptake and germ tube formation and was reversed by phosphates. Germinating and nongerminating cells differed in the rapidity and extent of GlcNAc incorporation into acid-insoluble and alkali-acid-insoluble cell fractions. During germ tube formation induced by proline, GlcNAc was almost totally incorporated into the acid-insoluble fraction after 60 min. Moreover, hyphal development on induction by either GlcNAc or proline was characterized by an apparent "uncoupling" between protein and polysaccharide metabolism, the ratio between the two main cellular constituents falling from more than 1 to less than 0.5 after 270 min of development. The data suggest that utilization of the inducer for wall synthesis is a determinant of germ tube formation C. albicans but that the nature and extent of inducer uptake is not a key event for this phenomenon to occur.

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