Determination of anti-Aspergillus activity of antifungal agents based on the dynamic growth rate of a single hypha

Abstract

The dynamic growth rate of a single hypha of Aspergillus niger was analysed using an automatic system. A colony of A. niger was in contact with saline, saline containing an antifungal agent, and flushing saline, in sequence. The growth rate of a test hypha selected arbitrarily from the colony responded dynamically to the antifungal agent. The minimum concentration that caused the complete inhibition of hyphal growth was defined as the minimum inhibitory concentration (MIC). The MIC values obtained were compared with those determined by conventional methods based on increasing rate of colony diameter or dry matter weight.

Evaluation of the inhibitory effect of amphotericin B on the apical growth of F. solani using the BioCell‐Tracer® System

“…No report on standardisation of BioCell‐Tracer ® system automatic growth evaluation of Fusarium species was found previous to this study. There are only a few reports in the literature on Aspergillus species 8,10,11,16–19 .…”

“…One disadvantage of BCT ® system is that it is a time consuming experiment, where only one strain can be tested for each drug concentration by a specialised, trained technician. Oh et al [10] pointed out that the BCT ® method has been focusing on the statistical problem of whether one single hyphae can represent the total colony. To solve this problem, we evaluated 10 hyphae for each experiment and calculated the median values obtained by BCT ® .…”

“…For each measurement, the two‐dimensional brightness patterns around the marker were analysed to determine the position of the apex, which was then plotted. A computer program calculated the growth rate during the measuring interval 10 . Preferentially unbranched hyphae were selected for the test.…”

“…The BioCell‐Tracer ® system (BCT) (Hidan Co., Ltd, Kashiwa, Japan) can detect the growth rate change of a single hyphae every 30 s with a precision of 0.1 μ m min −1 10 . This system is composed of a reaction vessel under microscope, automatic staging, charge coupled device (CCD) cameras, TV monitor, video tape recorder (VTR) and microcomputer (Fig.…”

Enhanced inhibition of Aspergillus niger on sedge (Lepironia articulata ) treated with heat-cured lime oil

“…Essential oils (Matan et al 2011), gamma irradiation (Aldred et al 2008) or chemical preservatives (Oh et al 1993) are among the many methods that have been developed to reduce surface mould. Recent studies to determine the efficacy of lime oil as an antifungal agent have shown that lime oil can control the growth of micro-organisms (Matan and Matan 2008;Mahmud et al 2009).…”