Revival of saprotrophic and mycorrhizal basidiomycete cultures after 30 years in cold storage in sterile water.

Vegetatively colonized agar cores of 54 basidiomycete fungal isolates were stored at 5 °C in tubes of sterile distilled water without manipulation for 30 years. The cultures represented 28 isolates of saprotrophic fungi and 26 isolates of mycorrhizal fungi. These cultures came from a group of 57 fungal isolates that were determined to be viable after 20 years of cold-water storage. Overall, 47 of the 54 isolates (87%) grew vigorously when revived after storage for 30 years. Of the 28 saprotrophic fungal isolates, 26 revived (93%); of the 26 mycorrhizal fungal isolates, 21 revived (81%). Eight of 13 isolates (62%) of Laccaria were viable after 30 years, which was considerably less viable than what was found after 20 years for this genus of mycorrhizal fungi. However, a greater percentage of isolates of Laccaria bicolor (83%) were viable than isolates of Laccaria laccata (43%), suggesting that 30 years is approaching the maximum limit for storage in cold sterile water for certain species. Considering the original 135 fungal isolates that were stored in sterile cold water from which this set was derived, overall survival after 30 years of storage was 42%; however, saprotrophic fungi demonstrated considerably greater viability (70%) than mycorrhizal fungi (21%).

Association of Pinus banksiana Lamb. and Populus tremuloides Michx. seedling fine roots with Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina).

Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina, Hydanaceae), commonly regarded as a wood decay fungus, was consistently isolated from bareroot nursery Pinus banksiana Lamb. seedlings. S. brinkmannii was found in ectomycorrhizae formed by Thelephora terrestris Ehrh., Laccaria laccata (Scop.) Cooke, and Suillus luteus (L.) Roussel. In pure culture combinations with sterile P. banksiana and Populus tremuloides Michx. seedlings, S. brinkmannii colonized root cortical cells while not killing seedlings. Colonization by S. brinkmannii appeared to be intracellular but typical endo- or ectomycorrhizae were not formed. The fungus did not decay roots, although it was shown to produce cellulase in enzyme tests. Results suggest a unique association between S. brinkmannii and seedling roots that is neither mycorrhizal nor detrimental; its exact function remains to be elucidated.

Comparison of effectiveness of wood decay fungi maintained by annual subculture on agar and stored in sterile water for 18 years.

Fourteen isolates of basidiomycete decay fungi (12 species) were maintained for 18 years on agar slants transferred annually and also stored as mycelium-agar cores under cold sterile water without subculture. Isolates stored by each method were evaluated for decay effectiveness using a standard laboratory accelerated soil-block decay test. Effectiveness was measured by mean percent mass loss of wood blocks. There was no significant difference (p < or = 0.05) in decay effectiveness between storage methods for 12 of the fungus isolates tested. For the 2 fungi that showed a significant difference in the amount of decay with respect to storage method, 1 fungus (Fomitopsis lilacinogilva) produced more decay by the strain maintained as an agar slant, while the other fungus (Trametes versicolor) produced more decay by the strain stored in sterile water. Results suggested that storage under sterile water is an easy and effective method to store isolates of decay fungi for long periods, but as with any microbial storage method, careful monitoring of isolates upon revival is necessary.

Revival of saprotrophic and mycorrhizal basidiomycete cultures after 20 years in cold storage in sterile water.

Vegetatively colonized agar cores of 69 basidiomycete fungus isolates (48 species in 30 genera and 17 families) were stored at 5 degrees C in tubes of sterile distilled water without manipulation for 20 years. These were represented by 34 isolates of saprotrophic fungi (29 species in 19 genera) and 35 isolates of mycorrhizal fungi (19 species in 11 genera). Viability was evaluated based on revived growth on agar media at room temperature. Fifty-seven of the 69 isolates (82.6%) grew vigorously when revived after storage for 20 years; of the 34 saprotrophic fungus isolates, 30 revived (88.2%); of the 35 mycorrhizal fungus isolates, 27 revived (77.1%). Thirteen isolates of Laccaria were all viable after 20 years, indicating cold storage in sterile water to be a good method for maintaining this important genus of mycorrhizal fungi. In general, however, mycorrhizal fungus species demonstrated lower viability than saprotrophic fungi.

Differential sensitivity of fungi to lithium chloride in culture media.

Forty species of fungi, representing a range of ecological and taxonomic groups, were tested for their ability to grow on agar media amended with lithium chloride (LiCl) at 1.5, 3 and 6 g l(-1). Species of Trichoderma varied considerably in their sensitivity to LiCl; at one week on 6 g l(-1) LiCl medium, the growth of seven species of Trichoderma was considerably inhibited; however, by three weeks at this level, four of the species tested were able to attain > or =30% of control growth. Of the seven species tested, an isolate of T. viride was the most sensitive to LiCl in agar. Eleven other imperfect fungi also showed a range of ability to grow on agar amended with LiCl, from total inhibition to complete lack of inhibition. Six ascomycete fungi were greatly inhibited by LiCl at all levels; however, an isolate of Chaetomium globosum was highly tolerant of LiCl. Seven basidiomycete wood-decay fungi were quite sensitive to LiCl in agar, showing total to nearly total inhibition even at the lowest level; however, after three weeks, an isolate of Postia placenta was nearly uninhibited except at 6 g l(-1). Five ectomycorrhizal basidiomycete fungi were totally inhibited by all levels of LiCl; however, one ectomycorrhizal imperfect fungus (Cenococcum graniforme) was able to grow at 3 g l(-1) and was uninhibited at 1.5 g l(-1). Four zygomycete fungus isolates were nearly unaffected in their growth by all levels of LiCl.

The mare reproductive loss syndrome and the eastern tent caterpillar: a toxicokinetic/statistical analysis with clinical, epidemiologic, and mechanistic implications.

During 2001, central Kentucky experienced acute transient epidemics of early and late fetal losses, pericarditis, and unilateral endophthalmitis, collectively referred to as mare reproductive loss syndrome (MRLS). A toxicokinetic/statistical analysis of experimental and field MRLS data was conducted using accelerated failure time (AFT) analysis of abortions following administration of Eastern tent caterpillars (ETCs; 100 or 50 g/day or 100 g of irradiated caterpillars/day) to late-term pregnant mares. In addition, 2001 late-term fetal loss field data were used in the analysis. Experimental data were fitted by AFT analysis at a high (P <.0001) significance. Times to first abortion ("lag time") and abortion rates were dose dependent. Lag times decreased and abortion rates increased exponentially with dose. Calculated dose x response data curves allow interpretation of abortion data in terms of "intubated ETC equivalents." Analysis suggested that field exposure to ETCs in 2001 in central Kentucky commenced on approximately April 27, was initially equivalent to approximately 5 g of intubated ETCs/day, and increased to approximately 30 g/day at the outbreak peak. This analysis accounts for many aspects of the epidemiology, clinical presentations, and manifestations of MRLS. It allows quantitative interpretation of experimental and field MRLS data and has implications for the basic mechanisms underlying MRLS. The results support suggestions that MRLS is caused by exposure to or ingestion of ETCs. The results also show that high levels of ETC exposure produce intense, focused outbreaks of MRLS, closely linked in time and place to dispersing ETCs, as occurred in central Kentucky in 2001. With less intense exposure, lag time is longer and abortions tend to spread out over time and may occur out of phase with ETC exposure, obscuring both diagnosis of this syndrome and the role of the caterpillars.