D-Glucose soluble starch, a novel medium for inducing microcyclic conidiation in Aspergillus

Saxena, Rajendra Kumar; Khurana, Nitika; Kuhad, Ramesh Chander; Gupta, Rani

doi:10.1016/s0953-7562(09)81096-4

Cited by 11 publications

(10 citation statements)

References 6 publications

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“…A . fEav~.r was maintained on a complete medium (Saxena & Sinha, 1973;Saxena, 1976) slants at 4 OC. For initiation of liquid cultures, conidia were harvested from 3-d-old agar cultures using normal saline and 0.01 % Tween-80 as a detergent.…”

Section: Methodsmentioning

confidence: 99%

Polyamines as Modulators of Microcycle Conidiation in Aspergillus Flavus

et al. 1996

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Since polyamines (PAS) play a potential role in the regulation of growth and developmental processes in a wide variety of organisms, we have examined the influence of the PAS putrescine (Put) and spermidine (Spd) and the PA biosynthetic inhibitors a-difluoromethylornithine (DFMO), adif luoromethylarginine (DFMA), methylglyoxal bis-(guanylhydrazone) (MGBG) and cyclohexylamine (CHA), singly and in combinations on microcycle conidiation (MC) in Aspergillus flaws. The exogenous application of the diamine Put (concentrations ranging from 01 to 5 mM) caused a sharp decline of MC in a dose-dependent fashion, but induced vegetative growth. However, the triamine Spd (01-5 mM) had a minimal effect on M C and induced a shift from M C to normal conidiation. PA inhibitors, especially DFMO, MGBG and CHA, produced greater inhibition of MC and complete inhibition of M C was observed at 5 mM of these inhibitors. DFMA even at 5 mM had only a weak inhibitory effect on MC. DFMO also inhibited conidial germination and germ tube growth. MGBG and CHA, while having an inhibitory effect on MC, induced vegetative growth. The inhibitory effect of PA inhibitors was partially reversed by exogenous Put or Spd, with Spd being more effective than Put. The analysis of free PA levels during various phases of M C revealed that undifferentiated spores contained a high Put/Spd ratio and there was a dramatic decrease in Put/Spd ratio before and during microcycle conidiophore maturity. The change in spermine titres could not be detected. These observations imply that Put is essential for vegetative growth, while S p d is involved in MC, and that a low Put/Spd ratio seems to be important for spore differentiation to MC.

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Section: Methodsmentioning

confidence: 99%

Polyamines as Modulators of Microcycle Conidiation in Aspergillus Flavus

et al. 1996

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“…Spherical cells might be an adaptation by these fungi (Saxena et al 1992). In microcyclic conidiation, immediate conidiation occurs following conidial germination without an intervening phase of prolonged vegetative mycelium.…”

Section: Not Done Not Done Mycelium (Pm)mentioning

confidence: 99%

“…In microcyclic conidiation, immediate conidiation occurs following conidial germination without an intervening phase of prolonged vegetative mycelium. Microconidiation is reported to occur under nutrient-limiting conditions (see Saxena et al 1992) and might help the fungi to complete their life cycles in a shorter time. Germination of conidia and growth of mycelium in the 2 species of terrestrial fungi under hydrostatic pressures of 100 and 200 bar, albeit lower than that at 1 bar, indicate their capability to withstand deep-sea high pressure conditions.…”

Section: Not Done Not Done Mycelium (Pm)mentioning

confidence: 99%

Barotolerance of fungi isolated from deep-sea sediments of the Indian Ocean

Raghukumar¹,

Raghukumar²

1998

Aquat. Microb. Ecol.

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Two species of filamentous fungi, AspergiUus ustus (Bain.) Thom & Church and Graphium sp., were isolated from calcareous animal shells at depths of 860 m in the Arabian Sea and 965 m in the Bay of Bengal. Laboratory experiments showed germination of conidia, growth of hyphae and microconidiation in both the fungi at 100 bar pressure at 10 and 30°C suggesting barotolerance The fungi also secreted barotolerant protease under these conditions. Protease synthesised and secreted in cultures grown at 1 bar was also active under 100 bar pressure at 10 and 30°C. At 1O0C, the fungi showed better conidial germination, growth and protease secretion when subjected to 100 bar than when grown at 1 atmosphere. The results indicate barotolerance of terrestrial species of fungl and suggest that they might be active under deep-sea conditions.

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“…has been achieved using a novel medium, D-glucose soluble starch (D-GSS) (9). Microcycle conidiation in the genus Aspergillus was observed to have several well-defined morphological stages.…”

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confidence: 99%

“…Stock solutions were filtered through a millipore membrane filter of pore size of 0.22 /tm. Different amounts of these were added to 50 ml of D-GSS medium (9).…”

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confidence: 99%