Tuatara: Volume 19, Issue 2, May 1972
Studies on the ‘Kerosene Fungus’ Cladosporium Resinae (Lindau) De Vries — Part II. The Natural Habitat of C. Resinae
Studies on the ‘Kerosene Fungus’ Cladosporium Resinae (Lindau) De Vries
Part II. The Natural Habitat of C. Resinae
|1.||The occurrence of C. resinae in hydrocarbons|
|2.||The occurrence of C. resinae on creosoted timbers|
|3.||The occurrence of C. resinae in soil|
|4.||The occurrence of C. resinae in the atmosphere|
|5.||The occurrence of C. resinae in other habitats|
|6.||Summary and conclusions|
In Part I of these studies the problem of microbial contamination of aviation fuel was discussed and the role of the ‘kerosene fungus’ Cladosporium resinae (Lindau) de Vries (perfect state Amorphotheca resinae Parbery) in contamination and corrosion evaluated. Part II deals with the natural habitat of this interesting fungus.
Cladosporium resinae is not only capable of growing in and utilising kerosene as a source of food, it can grow on wood impregnated with coal tar products such as creosote and utilise these products as food (Christensen, Kaufert, Schmitz and Allison, 1942). In the late 1930's several people (Dr. C. M. Christensen and his colleagues working at the Minnesota Agricultural Experiment Station, Dr. C. A. Richards of Forest Products Laboratory, Madison, Wisconsin, and Dr. J. D. Burns of Page and Hill Co., Robbinsdale, Minnesota) had occasionally observed a brown mould growing on small pieces of wood impregnated with coal tar products when placed in moist chambers or on agar during routine tests for resistance to decay (Christensen et al., 1942). Because of the known toxicity of these preservatives to micro-organisms in general these workers initially more or less disregarded this sporadic appearance of a fungus on treated wood and thought of it only as a laboratory phenomenon. This is understandable when one considers that coal tar products, especially creosote, have been used for over one hundred years to protect wood from attack by fungi, insects and other organisms. According to Christensen et al. (1942), each cubic foot of wood impregnated with these products contains 8 to 20 pounds, or 1 to 2½ gallons, of the preservative and the long service of timbers so treated is evidence of the value of the coal tar products as preservatives. However, in the fall of 1939 an investigation was initiated by page 71 Christensen and his colleagues into the identity of this mould and its occurrence in nature. Their findings were published in 1942. They concluded that the fungus was Hormodendrum resinae (= Cladosporium resinae — see Part III) which Lindau had described in 1907 from the resin of a conifer, Picea excelsa, and that it is a common inhabitant of wood treated with coal tar products including creosote. These workers also isolated the same fungus from resinous wood and from asphalt street pavements.
Some years later Marsden (1954) became interested in this fungus in connection with its possible deleterious effects on the preservative used to protect the wood against decay. He confirmed the findings of Christensen and his colleagues regarding occurrence on creosoted timbers and deep penetration into wood. He found fruiting structures produced within tracheid cavities as well as on the surface of the wood and indications that this mould may deleteriously affect the toxicity of creosote. He described five strains of the fungus (see Part III), and he coined the name ‘creosote fungus’ in 1954. Christensen and colleagues were unable to isolate C. resinae from soil except on one occasion (glasshouse soil) and neither they nor Marsden were able to isolate it from the air. The indications were, therefore, that C. resinae occurred naturally in resinous wood and on creosoted timbers, but not in soil.
With the implicating of C. resinae in contamination of jet aviation fuels and in corrosion of aircraft tanks in the 1960's interest in this fungus revived. Leonard and Klemme (1961) believed that this fungus could be soil-borne because most other Cladosporia could be isolated from the soil. But it was not until the late 1960's that this was confirmed by Parbery (1967). After devising a method which successfully isolated C. resinae from soil he investigated its occurrence in soils from Australia, Britain and Continental Europe. On the basis of his findings he concluded (1969b) that C. resinae is a natural component of the soil microflora and is widely distributed in nature. His conclusions are supported by the results of recent work in New Zealand (Sheridan, Steel and Knox, 1971).
None of the earlier workers were able to isolate C. resinae from the atmosphere yet Christensen et al. (1942) and Hendey (1964) were, according to Parbery (1969b), still of the opinion that it is airborne. Parbery (1969b) referred to three independent trappings of this fungus from the atmosphere, thus supporting this view. Within the last few years Harvey (1971—personal communication) has isolated C. resinae from the air in Wales in very small quantities, but consistently. More recently, using a method which selectively isolates this fungus from the air (Sheridan and Nelson, 1971b), it has been possible to trap it consistently from the atmosphere over Wellington, New Zealand (Sheridan, Sheridan, Hoverd and Nelson, 1971; Sheridan, 1971).page 72
From the foregoing it is quite clear that this extraordinary and intriguing, if not treacherous, fungus is very elusive. It has slipped through the fingers of the earlier workers when they have attempted to isolate it from soil and air. Results obtained by the use of new methods have given a better understanding of its distribution and role in nature but we will have to be patient until results from the wider application of these methods become available. In this paper the body of knowledge available at the present time on the occurrence of C. resinae in nature is reviewed in an attempt to determine its natural habitat.
1. The occurrence of C. resinae in hydrocarbons
The first report in the open scientific literature of the occurrence of Cladosporium resinae in hydrocarbon fuels appears to be that of Hendey in 1964. He reviewed the occurrence of this fungus in kerosene-type fuel storage tanks and fuel tanks of aircraft. Hazzard (1963) identified C. resinae in aviation kerosene in Australia in 1961 but his results are contained in a technical report which has not been widely circulated. In the same year Prince (1961) reported finding a Cladosporium sp. in jet fuel in the United States of America and his photographs indicate that it was probably C. resinae. As stated in Part I of these studies, contamination of kerosene-type fuels with page 73 C. resinae was widespread in the 1960's — until recently it was much easier to isolate this fungus from kerosene than from soil and Hendey's application of the name ‘kerosene fungus’ to this organism is indeed appropriate. The accompanying map (Fig. 1) shows the distribution of C. resinae in airfield fuel systems in Australia. The figures are taken from Hazzard (1963) but the map is incomplete because of the difficulty of locating some of the airfields. Figures are not yet available for New Zealand, hence the distribution of C. resinae cannot be plotted. (For figures for Australia and California see Part I.)
The fungus has been isolated from lighting and aviation kerosene in France (Nicot and Zakartchenko, 1966 — ‘Mazout, kérosène carburants pour l'aviation’) and we have isolated it from both of these in New Zealand. We were not able to confirm from the literature that C. resinae had been isolated from petrol (= gasoline), diesel oil or lubricating oils, but the first sample of petrol we examined yielded five colonies of C. resinae from 250 ml. of the sample. Fuel/water samples of aviation gasoline are at present under test.
C. resinae has been isolated from aviation fuel, from tank filters or aircraft fuel tanks in Australia (Hazzard, 1963), Brazil (Gutheil, 1966), Denmark, England, India, Nigeria, New Zealand, Syria (Anon., 1968), U.S.A. (Engel and Swatek, 1966) and Japan (Inoue, Iwamato and Minoura, 1965).
It has been reported that C. resinae can remain alive for rather a long time in kerosene-type fuels (Hendey, 1964). Nicot and Zakartchenko (1966) found the fungus in their samples to be alive after 30 months but the results of their tests were not consistent. Hazzard (1967) found that it could remain viable for several years in essentially water-free petroleum products. This aspect has not yet been studied in our laboratory.
Four forms of C. resinae are known to exist (see Part III) but only one, j. avellaneum, has apparently been recovered from kerosene-type fuels (Hendey, 1964; Inoue, Iwamoto and Minoura, 1965) (Table 1). C. resinae f. resinae has arisen in culture from f. avellaneum (Hendey, 1964) and been isolated occasionally from soil (Parbery, 1968). An albino has arisen in culture from f. avellaneum (Parbery, 1969a; Sheridan, Steel and Knox, 1971) and is morphologically similar to it (Figs. 2 and 5). De Vries (1955) gave the name f. albidum to an albino which was morphologically similar to f. resinae. For the present purpose we shall refer to both of these as f. albidum (see Part III).
The only form isolated by us directly from kerosene fuels (and soil) is C. resinae f. avellaneum. Both f. albidum and f. resinae have been found in New Zealand as saltants in culture. All three forms have been tested by us for ability to grow in kerosene; all were able to do so (see Fig. 3). Parbery's (1968) isolates of f. resinae frompage 74
|Prince||1961||Aviation Kerosene (U.S.A.)||Cladosporium sp.||(?f. avellaneum)|
|Hazzard||1961, 1962, 1963||" " (Australia)||Cladosporium resinae||f. avellaneum|
|Hendey||1964||" " (Britain)||C. resinae||f. avellaneum
f. resinae as saltant
|Inoue, Iwamoto and Minoura||1965||" " (Japan)||C. resinae||f. avellaneum|
|Nicot and Zakartchenko||1966||" " (France) (and Lighting Kerosene)||C. resinae||f. avellaneum|
|Engel and Swatek||1966||Aviation Kerosene (U.S.A.)||Hormodendrum resinae||——|
|Darby et al.||1968||" " (U.S.A.)||C. resinae||f. avellaneum|
|Sheirdan et al.||1971||" " (N.Z.) (and Lighting Kerosene)||C. resinae||f. avellaneum
and intermediates as saltants
2. The occurrence of C. resinae on creosoted timbers
Cladosporium resinae was repeatedly isolated from wood impregnated with creosote and coal tar, e.g. telephone poles and railway ties, by Christensen, Kaufert, Schmitz and Allison (1942). Samples were taken near the ground line from twenty-nine creosoted poles in Minnesota, Wisconsin, Pennsylvania and Delaware. C. resinae was isolated from twenty-seven of these. It was likewise isolated from six of eight creosoted ties sampled in Minnesota, and from all of eleven ties from Ohio, from all of four ties from Louisiana, three from the State of Washington, and from ties sampled in Missouri and Indiana. The fungus was also found on several creosoted southern pine fence posts in service for seventeen years in Iowa. These workers also successfully isolated this fungus from resinous woods.
Their work led the above workers to an investigation of the natural habitat of the fungus. Soil was tested around the University Farm, St. Paul, Minnesota, which included cultivated and uncultivated land, and soil near a creosoting plant but no C. resinae was found. Neither were they able to isolate it from the atmosphere. The reason for this failure to isolate the kerosene fungus from the soil and air was almost certainly due to the use of unsuitable techniques (see 3. The occurrence of C. resinae in soil). Marsden (1954) isolatedpage 76
|Lindau||1907||Resin of Pices excelsa (Europe)||Hormodendrum resinae (= Hormodendron)||——|
|Christensenet al.||1942||Resonous Wood (U.S.A.) Creosoted Timbers||H. resinae||(f. f. avellaneum)|
|Marsden||1954||Creosoted Timbers (U.S.A.)||H. resinae||(f. avellaneum)
Figure 3: Growth of C. resinae in aviation turbine kerosene. Left: f. avellaneum isolated from soil. Right: f. avellaneum isolated from air. Centre: f. albidum.
De Vries (1955) has studied various strains of Cladosporium resinae including two of Marsden's (1954). He concluded that Marsden's New York strain agreed with C. resinae f. avellaneum and his New York saltant strain with f. resinae (Fig. 5). The fungus isolated by Christensen et al. (1942) appears to be f. avellaneum (Table 2). De Vries tested the growth of five strains of the fungus on media containing 4% coal tar or 1% creosote. The strains tested were: 1, Enola; 2, ‘Christensen’ (received from Marsden); 3, C. resinae f. avellaneum; 4, C. resinae f. resinae; 5, C. resinae f. albidum. Contrary to De Vries's expectations, the last three strains did not grow on these media while the Enola and Christensen isolates made good growth. More recent work confirms that this fungus produces a wide variety of morphological forms and these vary in their ability to tolerate and grow in kerosene and creosote (Hendey, 1964; Parbery, 1969b). This aspect is dealt with more fully in Part III of these studies.
3. The occurrence of C. resinae in soil
Cladosporium resinae was first isolated successfully from soil by Parbery (1967), working in Australia. He devised the ‘creosoted matchstick method’ in which two decapitated matchsticks, sterilised and soaked in sterile creosote, were added to a Petri dish containing moistened soil (See Fig. 4). The plates were incubated at 25° C. along with control plates containing non-creosoted matchsticks for up to three weeks. In Victoria, Parbery took soil samples from the base of, and some distance from, test creosoted poles and from virgin bushland, 50 metres from the testing site. C. resinae appeared in twelve out of fourteen soil samples tested. Since the fungus appeared in four samples of soil from the virgin bushland, this was considered by Parbery (1967) to be a strong indication that the fungus occurs naturally in soils. This observation led Parbery to further studies on the distribution of C. resinae in soil (Parbery, 1969b). He collected sixty isolates of C. resinae from soils in Australia. Britain, France and Sweden, proving the fungus to be widely distributed and indicating that it is a natural component of the soil microflora. The collection sites of soil yielding C. resinae were:
In England — fallow soil, under pines and poplar, by a creosoted pole, from soil under a larch and under Norway spruce.
In Wales — garden soil, the bases of creosoted poles, grass tussock and soil under firs and pines.
In France — soil under juniper, Norway spruce, oak, beech, Picea pungens, Cedrela sinensis and a soil bitumen mixture near base of pole.
In Sweden — there were two positive isolations from Stockholm, under Picea pungens and under oak and elm.
In Australia — isolates from Victoria were collected from burned hilltop forest, alluvial soil, beside a creosoted pole, skeletal hillside, roadside under eucalypt, petrol station, virgin bush, mountain soil of virgin bush, sandy arid soil and under Pinus radiata.
In New Zealand this fungus was first isolated from a garden soil in Wellington, near a creosoted fowl house, in November, 1969 (Sheridan and Knox, 1970). A modification of Parbery's ‘creosoted matchstick method’ was used. The matchsticks were steeped in creosote for 48 hours, transferred to a clean beaker covered with aluminium foil, and then autoclaved for 30 minutes at 103 kNm-2. This modification ensured that very little liquid creosote was transferred to the soil. This is an advantage because none of our isolates would tolerate as much as 3% creosote and the presence of excess creosote could suppress growth. C. resinae has subsequently been found to be widespread in soil in this country (Figs. 6 and 7), occurring most frequently in and near built-up areas but also occurring occasionally in soils remote from human habitation.page 79 page 80
We have isolated C. resinae in New Zealand from cultivated garden soils, from soils at the base of creosoted poles and fence posts and soils at the edge of a tar spillage on a roadside, from the top of sawdust mounds on old saw mill sites (Ketetahi Mills, near Taurewa, and near spiral railway, Raurimu), from soil under grass, gorse, conifers, scrub and native bush and from sandy soil in the Rangipo Desert. It has been found from sea level up to 5,000 feet. The collection sites are shown in Table 3.
|Classification||No. of Samples||No. yielding C. resinae|
|Parks and reserves||48||24|
|Classification||No. of Samples||No. yielding C. resinae|
|Near creosoted poles and posts||47||32|
|On sand dunes, beach and desert||7||3|
Parbery (1969b) reports that there does not appear to be any correlation between isolation of C. resinae and any soil or vegetation type but there does appear to be some positive correlation between frequency of isolation and the annual average rainfall. This correlation could, in his opinion, be related to soil mosture or to organic matter content. This aspect warrants further study. In both Parbery's and our own studies not all soil samples taken beside creosoted poles yielded C. resinae, and several isolates were obtained from what is regarded as virgin soil.
Figure 7: Sampling sites for C. resinae in soils in Wellington area. Note position of Hirst spore trap. Red spot +ve, black spot —ve.
Parbery (1969b) reports that of seventeen isolates tested, seven were able to grow in medium with kerosene as the only carbon source. All of the New Zealand soil isolates tested by us were able to grow in medium with aviation turbine kerosene as sole source of carbon but not all isolates from kerosene fuel could do so (Sheridan and Nelson 1971a).
Data on the occurrence of C. resinae in soil and the forms of the fungus found is presented in Table 4.
4. The occurrence of C. resinae in the atmosphere
Figure 8: Diagrams of Hirst spore trap and air slit sampler. Left: Impactor unit on larger scale; approximately one-third natural size. Arrows indicate how the air circulates.
Harvey (1967; 1971 — personal communication) has isolated C. resinae from the air in Wales in very small quantities, but consistently over a period of years. Parbery (1969b) was apparently not aware of Harvey's work.
We became interested in the possibility that C. resinae was a significant component of the airspora in New Zealand because of its widespread occurrence in soils and profuse sporulation, but all our initial attempts to trap it failed. After some ten months work we eventually perfected a technique which consistently isolated the fungus from the air of our laboratory. The application of the same technique out-of-doors has resulted in numerous trappings. A Hirst spore trap (see Fig. 8) is in use which is capable of continuous operation for twenty-four hours unattended.
Because C. resinae grows readily on a wide variety of agar media containing creosote (Sheridan, Steel and Knox, 1971) and few other fungi (or bacteria) will tolerate the creosote, we experimented with the use of a selective medium containing creosote for the isolation of this fungus. The method described here is a simple one and has proved suitable for isolating C. resinae from the air in New Zealandpage 85
|Parbery||1967, 1968, 1969||Soils (Australia, Europe, Britain)||Cladosporium resinae
(= Amorhpotheca resinae)
|f. resinae (occasionally)
f. albidum) as saltant
|Sheridan et al.||1970, 1971||Soils (New Zealand)||C. resinae
(= Amorphotheca resinae)
f. albidum) as saltant
* morphologically similar for f. avellaneum
(Sheridan and Nelson, 1971b). The selective medium is prepared as follows. Forty grams of Davis agar (other brands should also be suitable) is added to 1,500 ml. tap water in a glass vessel which is heated in a boiling water bath until the agar melts. To this is added 350ml. of V-8 juice (Campbell's Soups Ltd.). The medium is mixed gently, distributed into medicine flats and autoclaved at 103 kNm−2 (15 p.s.i.) for 10 minutes. When the medium has cooled to about 50°C. sterile creosote (sterilised by autoclaving) is added aseptically to give a final concentration of 0.1%. The concentration is not critical since all strains of the fungus studied by us will tolerate creosote up to 1%. However, a lower concentration is undesirable because the volatile components of the creosote disappear rather rapidly when plates containing the selective medium are exposed to the air.
Plates of this selective medium are exposed in an Air Slit Sampler (see Fig. 8) with an intake of 18 litres of air per minute, for periods of up to 30 minutes. An exposure of less than 30 minutes is uneconomical; a longer exposure results in growth of contaminants and unreliable results. After exposure, plates are incubated at 25° C. for 5 days. Colonies of the fungus can be recognised visually and by the characteristic smell produced on this medium and confirmed by microscopic examination (see Figs. 2 and 5).
For continuous monitoring of the air we use a Hirst Spore Trap (see Fig. 8) operating 2 metres above the ground with an intake of 10 litres/min., carrying a microscope slide coated with vaseline. When the slide is removed after exposure it is placed into a sterile Petri dish and sterile selective medium at 50° C. is gently poured over the slide. These preparations are incubated as above and colonies identified after 5 days.
Because the volume of air taken into the trap and the rate of movement of the slide past the orifice is known it is possible (assuming that each colony develops from a single spore) to determine the concentration of C. resinae in the air and the time at which the spore landed on the slide (Fig. 9).
For selective isolation of the fungus from air at oil installations, airports and on aircraft during flight, trappings are made on a sterile glass fibre paper in a Personal Dust Sampler (Figs. 10 and 11). After each run (1-8 hrs.) the paper is removed aseptically and placed inside a sterile disposable plastic universal container for transport to the laboratory. On arrival it is placed inside a sterile Petri dish, correct side up, and selective medium at 50° C. is poured over it. Alternatively, 5 ml. of the medium may be added to the universal container. Incubation is as above.
Results of Air Trappings Over Wellington
1. Using the Air Slit Sampler
Figure 9: Colonies of C. resinae (arrowed), trapped from the air, after five days on V-8 juice agar containing 0.1% creosote. Hirst spore trap.
Figure 10: Colonies of C. resinae, trapped from the air, after five days on V-8 juice agar containing 0.1% creosote. Personal dust sampler.
|Location||Date||Time||No. of Spores of C. resinae trapped||Weather|
|Brooklyn Wellington||Nov. 21||9.00-9.30 p.m.||1||Dry, mild, It. sthly.|
|Nov. 21||9.30-10.00 p.m.||1||Dry, mild, It. sthly.|
|Dec 6||9.15-9.45 a.m.||1||(Dry, very warm|
|9.45—10.15 a.m.||1||(Gusty, nthly.|
|Dec. 7||9.45-11.30 a.m.||1||Dry, mild, calm|
|Dec. 8||8.45-9.00 p.m.||1||Dry, mild, It. sthly.|
|Dec. 25||12.30-2.00 p.m.||3||Dry, overcast, mild, gusty nthly.|
|Dec. 29||5.30-6.00 p.m.||1||Dry, very hot, calm|
|Dec. 30||1.20-2.00 p.m.||1||Dry, hot, calm|
2. Using the Hirst Spore Trap
This spore trap has been operating continuously, day and night, in Brooklyn since March 14, 1971 (see Fig. 7 for location). Up to July 21, 1971, 26 isolations of C. resinae have been made. Eleven were trapped during dry weather, 4 of the remaining 15 during heavy rain; 12 were trapped during daylight, 14 were trapped during darkness (Table 6). There is thus little evidence for the deleterious effect of light or for a preference for wet weather in dispersal. Presumably the spores trapped originated from the soil since the trap is operating in a region where the fungus is known to exist in the soil. Seagulls and other birds may also be implicated since the fungus has been isolated from feathers. (See 5. Occurrence of C. resinae in other habitats.) This work is continuing, but there is now little doubt that C. resinae forms a significant component of the air spora over Wellington.
3. Using the Personal Dust Sampler
Monitoring of the air of our laboratory at intervals from April to June, 1971, using this sampler has shown a concentration of C. resinae from 0 to 12 per cu. metre with an average of 6 (Table 7). The higher concentration occurred when we were harvesting C. resinae from kerosene in experiments to determine dry weights. Only one trapping has been made with this sampler from the air atpage 89
|Location||Date||Time||No. of Spores of C. resinae trapped||Weather|
|Brooklyn||March 23||11.00 p.m.||1||Dry|
|Wellington||March 26||7.00 a.m.||1||Showery|
|March 30||9.00 a.m.||1||Dry|
|March 31||3.00 a.m.||1||Showery|
|April 1||8.00 p.m.||1||Dry|
|April 3||11.00 p.m.||1||Dry|
|April 6||2.00 a.m.||1||Dry|
|April 12||(8.00 a.m.||2||Dry|
|April 22||7.00 a.m.||1||Heavy rain|
|April 24||2.30 p.m.||2||Dry|
|May 3||2.30 p.m.||2||Drizzle|
|May 5||9.00 p.m.||1||Heavy rain|
|May 9||9.00 a.m.||1||Showery, stormy|
|May 12||12.30 a.m.||1||Dry|
|May 14||3.30 p.m.||1||Showery|
|May 16||8.00 a.m.||1||Heavy rain|
|May 19||9.00 p.m.||1||Showery|
|May 24||6.30 p.m.||1||Heavy rain|
|May 28||7.00 p.m.||1||Dry|
|June 7||11.00 p.m.||1||Rain|
|June 12||8.00 p.m.||1||Showery|
|July 2||5.00 a.m.||1||Showery, very cold|
|July 4||12.00 midnight||1||Showery, very cold|
|July 7||8.00 p.m.||1||Showery, very cold|
Karori (23/5/71) and one at the University Field Station, Taurewa, National Park (20/5/71). No fungus has been isolated yet from Wellington Airport, on aircraft or at oil installations in the few tests so far run. Further work is in progress.
The key factor in the isolation of C. resinae from the air is the use of a selective medium. V-8 juice agar containing 0.1% creosote has proved ideal. The acid medium suppresses growth of bacteria, and the creosote suppresses growth of most fungi. Certain precautions must be taken to avoid contamination with C. resinae from within the laboratory. Where possible, preparations of materials, pouring of media and incubation should be done in a place remote from the laboratory. In recent tests the air of our laboratory yielded an average of six spores (assuming each colony arises from a single spore) per cubic metre. The air above Wellington (at Brooklyn) during a trapping schedule in November and December, 1970, yielded 1 spore per 20 cu. m.page 90
|Location||Date||Duration of trapping||Time at which C. resinae trapped||No. of Spores of C. resinae trapped|
|Our Laboratory||April 5||8 hours||9.30-10.30 a.m.||1|
|"||April 22||8 hours||—||—|
|"||April 27||4 hours||—||—|
|"||April 28||9 hours||11.45 a.m.-2.00 p.m.||2|
|"||May 25||5 hours||12 noon-2.00 p.m.||1|
|"||May 26||9 hours||8.00-10.00 a.m.||5|
|10.00 a.m.-1.00 p.m.||4|
|3.30 p.m.-5.00 p.m.||2|
|"||May 27||7 hours||9.00-11.00 a.m.||4|
|11.00 a.m.-1. p.m.||8|
|"||May 31||8 hours||8.00-11.45 a.m.||4|
|11.45 a.m.-2.30 p.m.||2|
|"||June 1||8½ hours||8.30-10.30 a.m.||1|
|"||June 2||5 hours||9.00-11.00 a.m.||1|
|11.00 a.m.-1.00 p.m.||1|
|"||June 9||7½ hours||8.45-10.00 a.m.||3|
|10.00 a.m.-12.00 noon||1|
|12.00 noon-2.00 p.m.||1|
Each of the spore traps serves a different purpose. The Hirst spore trap is ideal for continuous monitoring. The personal dust sampler has proved useful for monitoring air inside aircraft, at airports and at oil installations. The air slit sampler is used as a standard against which the others are compared periodically to check on their efficiency.
Only f. avellaneum has been so far isolated from the atmosphere by us. This is not surprising since f. albidum has not been found in soil and f. resinae is only occasionally isolated from soil (Parbery, 1968). We have not isolated f. resinae directly from soil in New Zealand. Further, this form sporulates sparsely and spores are difficult to dislodge.
How to Make a Simple, Efficient Sampler for Trapping C. Resinae from the Air
Figure 12: Apparatus for air sampling for C. resinae constructed from a vacuum cleaner and pieces of plastic water pipe (Belinda’) Approximately one-quarter natural size.
5. The occurrence of C. resinae in other habitats
Apart from its occurrence in kerosene, petrol, creosoted timbers, asphalt, soils, and in the air, C. resinae has been isolated from a cosmetic face cream (de Vries, 1952) bituminised cardboard (Anon., 1968), the female sex hormone, progesterone (Fonken, Murray and Reineke, 1964), methyl-p-hydroxybenzoate (Sokolski, Chichester and Honeywell, 1965) and feathers of birds (Sheridan, 1971) (Table 9). In connection with this last source we have made two isolations from chicken feathers and ten from seagull feathers collected in Wellington. The feathers were picked up from the ground or on the beach, cut to size and placed on V-8 juice agar containing 0.1% creosote, in Petri dishes, and incubated at 25° C. for five days. In studies on the dissemination of fungi by migratory birds, Warner and French (1970) have recovered viable spores of C. resinae as long as forty-five days after being applied to birds. Further, Parbery (1969) has found feathers to be an excellent substrate for growth of some of his soil isolates of the fungus. It is anticipated, therefore, that C. resinae will be found, on investigation, to occur on feathers in many countries.
It has been estimated that more than 150 gallons of jet fuel are released into the atmosphere each day from aircraft operating over London (Anon., 1970). This ‘Heathrow Dew’ could conceivablypage 93
|Anon.||1961||* air filter||C. resinae||—|
|Harvey||1967||atmosphere (over Cardiff, Wales)||C. resinae||—|
|Chabert||1968||atmosphere (over Rabat, Morocco)||C. resinae||—|
|(Parbery)||1969||* atmosphere (over Johannesburg, S. Africa)||C. resinae||—|
|Sheridan et al.||1971||atmosphere (over Wellington, New Zealand)||C. resinae||f. avellaneum|
* One isolate only
|De Vries||1952||Cosmetic Face Cream||** Cladosporium resinae||f. avellaneum
from a single culture spore
|Fonken, Murray and Reineke||1960||Female Sex Hormone, Progesterone||Cladosporium resinae||—|
|Anon.||1964||Bituminised Cardboard||Cladosporium resinae||f. albidum|
|Sokolski, Chidester and Honeywel||1965||Methyl-p-hydroxybenzoate||Cladosporium resinae||—|
|* Warner and French||1970||Feathers (North America)||Cladosporium resinae||—|
|Sheridan||1971||Feathers (New Zealand)||Cladosporium resinae||f. avellaneum|
** Called Cladosporium avellaneum in 1952: later renamed C. resinae.
* Applied to birds and then recovered 45 days later.
contaminate birds, particularly seagulls which are often present in great numbers near airports, and C. resinae might be thus deposited on their feathers. Also these birds might pick up spores of C. resinae from the air (See 4. The occurrence of C. resinae in air) and the kerosene select in its favour. Birds may, therefore, be of some significance in spreading C. resinae from place to place.
The forms isolated from the cosmetic face cream (De Vries, 1955) were C. resinae f. avellaneum and C. resinae f. resinae; from bituminised cardboard, from a gold mine in South Africa, C. resinae f. albidum. Only f. avellaneum has been isolated by us from feathers.
When the white settlers first arrived in New Zealand last century they were struck by the majesty of the magnificent kauri forests (Agathis australis) in the north of the North Island. The trees proved very valuable as a source of durable timber with the result that only a few thousand acres of trees remain. C. resinae grows readily on kauri gum and it is possible that the fungus occurs naturally in soils in the old kauri forests. We are looking into this but have not yet been able to visit these areas to procure soil samples.
6. Summary and conclusions
The ‘kerosene fungus’, Cladosporium resinae, is widespread as a contaminant of kerosene-type fuels, occurs frequently on creosoted timbers, is widely distributed in soil, occurs on feathers and in the air and has been reported from other habitats. There is little doubt that the soil constitutes the natural habitat of this rather extraordinary fungus. From here the fungus can contaminate power poles and fence posts, being selected for by creosote, and enter fuel supply systems with contaminating soil. Airborne spores can, no doubt, find their way into fuel storage and aircraft tanks. The form most frequently isolated from soil, f. avellaneum, is the one most frequently isolated from creosoted timbers, fuels and air. This is to be expected because of its profuse sporulation and ease with which these spores become airborne. The albino, f. albidum, has only been found in culture, with one exception (Anon., 1968), but there appears to be no reason why it should not occur in nature since it can grow readily in kerosene and in the presence of creosote, and sporulates as profusely as f. avellaneum.
The other form, f. resinae, is only occasionally isolated from soil but because it does not sporulate as freely as the other two forms and because the spores are difficult to dislodge from the conidiophores its spread will be restricted. C. resinae f. sterile and intermediate forms have been found in culture by Parbery (1969a) and by us.
Now that reliable methods are available for isolating C. resinae from soil and air new knowledge about the distribution of this fungus will accumulate rapidly.
The work which was carried out in our laboratories was supported in part by grants from the Victoria University of Wellington Internal Research Committee. The Hirst spore trap was purchased with a U.G.C. grant. We are grateful to the Chief Superintendent of the Australian Defence Standards Laboratories for permission to quote data contained in D.S.L. Report No. 252 and to the Operations Manager of N.A.C. for permission to sample the air at airports and on aircraft in New Zealand. Thanks are also due to members of the Botany and Zoology Department of this university and to everyone else who assisted in the soil survey. Mr. Ron Hoverd constructed the apparatus shown in Fig. 13.
(References will be combined with those for Part III.)