Colonization and lignin decomposition of Camellia japonica leaf litter by endophytic fungi

Endophytic fungi occur on various types of leaf litter, but few studies have been done on their roles as saprophytes in decomposition. This study examined the succession of fungi in live, newly shed, and decomposing leaves at 2 months of decomposition of Camellia japonica and chemical changes in decomposing leaves colonized by endophytes. Coccomyces nipponicum, Lophodermium sp., Geniculosporium sp. 1, and Colletotrichum gloeosporioides were isolated from living leaves. Coccomyces nipponicum and Lophodermium sp. were also isolated frequently from newly shed and decomposing leaves. These two fungi caused a decrease of lignin content and bleaching in decomposing leaves under field and laboratory conditions. Total hyphal length in decomposing leaves was higher in bleached portions than in surrounding nonbleached portions, which probably reflected the early onset of hyphal growth of endophytes inside leaf tissue at leaf senescence or death. Incubation of newly shed leaves that were sterilized to exclude previously established endophytes resulted in no occurrence of bleached portions in decomposing leaves on the forest floor. This result indicated that these endophytes were incapable of colonizing leaves directly after litterfall and that the persistence of endophytes from live leaves was crucial for their colonization in decomposing leaves.     

Association of pharaonis phoborhodopsin with its cognate transducer decreases the photo-dependent reactivity by water-soluble reagents of azide and hydroxylamine

pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a receptor of the negative phototaxis of Natronobacterium pharaonis. In halobacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. In the present work, the truncated transducer, t-Htr, was used which interacts with ppR [Sudo et al. (2001) Photochem. Photobiol. 74, 489-494]. Two water-soluble reagents, hydroxylamine and azide, reacted both with the transducer-free ppR and with the complex ppR/t-Htr (the complex between ppR and its truncated transducer). In the dark, the bleaching rates caused by hydroxylamine were not significantly changed between transducer-free ppR and ppR/t-Htr, or that of the free ppR was a little slower. Illumination accelerated the bleach rates, which is consistent with our previous conclusion that the reaction occurs selectively at the M-intermediate, but the rate of the complex was about 7.4-fold slower than that of the transducer-free ppR. Azide accelerated the M-decay, and its reaction rate of ppR/t-Htr was about 4.6-fold slower than free ppR. These findings suggest that the transducer binding decreases the water accessibility around the chromophore at the M-intermediate. Its implication is discussed.     

Fungal colonization and decomposition of Castanopsis sieboldii leaves in a subtropical forest

Fungi play a crucial role in the decomposition of lignin in fallen leaves but few studies have examined the functional roles of ligninolytic fungi associated with the decomposition of fallen leaves on tropical forest soils. This study examined fungal populations responsible for lignin decomposition in Castanopsis sieboldii leaves in a subtropical evergreen broad-leaved forest in southern Japan. Fallen leaves of C. sieboldii are characterized by the occurrence of bleached portions attributable to fungal colonization of leaf tissues and decomposition of lignin. The bleached area accounted for 29.7%, on average, of the total area of C. sieboldii fallen leaves in the study site. Leaf mass per unit area (LMA) and lignin content were lower in the bleached area than in the surrounding nonbleached area of the same leaves, indicating that removal of lignin enhanced mass loss from leaf tissues and created small-scale heterogeneity of decomposition within single leaves. An unidentified species of Lachnocladiaceae (Basidiomycetes) was isolated frequently from the bleached area and caused selective decomposition of lignin in leaves under pure culture conditions, indicating that this fungus was responsible for the bleaching. The greater hyphal length of basidiomycetes in the bleached area than in the nonbleached area supported the finding that this Lachnocladiaceae sp. was associated with the bleaching. The relatively rapid decomposition of C. sieboldii leaves on the subtropical forest soil is partly attributable to colonization of the litter by this Lachnocladiaceae sp.     

Experimental method for isolating and identifying dust mites from sputum in pulmonary acariasis

The aim of this study was to pilot a simpler and more effective method for identifying dust mites in sputum. Dust mites and their allergens have been implicated in respiratory diseases, including pulmonary acariasis, and several studies have identified mites in sputum. Further research is dependent on the development of a faster and simpler diagnostic test. We have demonstrated that dust mites artificially introduced into sputa, could be identified after the sputa were liquefied with bleach, when the liquid sample was observed under the microscope. Liquefaction times for serous, mucous, purulent and hemoptoic sputa varied from 10 to 30 min (mean 17.5). The test had a sensitivity of 80% (95% CI 68.2–88.2%) as 46/60 mites were identified. This procedure can be performed quickly at room temperature, is simple, inexpensive, repeatable, and less labourious than previous methods.     

Geographical distributions of rhytismataceous fungi on Camellia japonica leaf litter in Japan

Rhytismataceous fungi (Ascomycota) exhibit ligninolytic activities during the initial stages of litter decomposition. We quantitatively investigated the geographical distributions of rhytismataceous fungi on Camellia japonica leaf litter across Japan. We found three rhytismataceous species (Coccomyces sp., Lophodermium jiangnanense, and a Rhytismataceae sp.) on bleached leaves of C. japonica. The Coccomyces sp. was distributed at all 40 sites investigated. On the other hand, L. jiangnanense was restricted to the southwestern region, and the Rhytismataceae sp. was localized to part of the warm-temperate zone. L. jiangnanense and the Rhytismataceae sp. were more common at sites with higher annual temperatures and greater precipitation. The relative abundance of rhytismataceous fungi revealed that either Coccomyces sp. or L. jiangnanense predominated at all sites, with a distribution related to annual precipitation. These results suggest that the geographical distributions and abundances of rhytismataceous fungi are influenced by climatic conditions.     

Fungal succession and decomposition of <Emphasis Type="Italic">Camellia japonica</Emphasis> leaf litter

Decomposition processes of Camellia japonica leaf litter were investigated over an 18-month period with reference to the role of fungal succession in the decomposition of lignin and holocellulose. Decomposition and fungal succession were studied in bleached and nonbleached portions of litter, which were precolonized by ligninolytic and cellulolytic fungi, respectively. Coccomyces nipponicum and Lophodermium sp. (Rhytismataceae), which can attack lignin selectively, caused mass loss of lignin and were responsible for bleaching during the first 4 months (stage I), whereas cellulolytic fungi caused mass loss of holocellulose in adjacent nonbleached portions. Soluble carbohydrates and polyphenols also decreased rapidly during this stage. Pestalotiopsis guepini, coelomycete sp.1, and the Nigrospora state of Khuskia oryzae caused mass loss of holocellulose between 4 and 14 months (stage II) and Xylaria sp. caused mass loss of both lignin and holocellulose from 14–18 months (stage III). In stages II and III, decomposition was more rapid in bleached portions than in nonbleached portions probably due to the prior delignification of lignified holocellulose in bleached portions. Frequencies of these fungi showed different responses among species to the pattern of changes in lignin and holocellulose contents during decomposition. Total hyphal length increased in both portions over the study period, but mycelia of basidiomycetes accounted for about 2% of total hyphal length, suggesting that their role in fungal succession and decomposition was low. Lignin and nitrogen contents were consistently lower and holocellulose content was higher in bleached portions than in nonbleached portions during decomposition. The succession of ligninolytic and cellulolytic fungi was a major driving factor that promoted decomposition and precolonization by ligninolytic fungi enhanced decomposition.     

Ecology of ligninolytic fungi associated with leaf litter decomposition

Advances in our understanding of the decomposition processes in forest ecosystems over the past three decades have demonstrated the importance of lignin as a regulating factor in the decomposition of leaf litter. Consequently, increasingly more attention is being focused on the ecology of fungi associated with lignin decomposition. The aim of this review is to provide a critical summary of the ecology of ligninolytic fungi inhabiting leaf litter and forest floor materials. The review focuses on the following aspects of ligninolytic fungi: the taxonomic and functional diversity of ligninolytic fungi, the outcomes of interactions between ligninolytic fungi and other organisms, the activity and abundance of ligninolytic fungi measured by the production of bleached leaves and humus, the activity of ligninolytic enzymes in soil environments, the substratum and seral succession, spatial and temporal patterns in both mycelial abundance and species distribution, and the effect of environmental factors such as nitrogen deposition and global environmental changes on ligninolytic fungi. This review integrates the ecology, diversity, and activity of ligninolytic fungi into the context of an ecosystem in order to provide an understanding of the roles of ligninolytic fungi in decomposition processes. Takashi Osono is the recipient of the 11th Denzaburo Miyadi Award.     

Environmental assessment of enzyme assisted processing in pulp and paper industry

Background Aims and Scope  The pulp and paper (P&P) industry is traditionally known to be a large contributor to environmental pollution due its large consumptions of energy and chemicals. Enzymatic processing, however, offers potential opportunities for changing the industry towards more environmentally friendly and efficient operations compared to the conventional methods. The aims of the present study has been to investigate whether the enzyme technology is a more environmentally sound alternative than the conventional ways of producing paper. The study addresses five enzyme applications by quantitative means and discusses the environmental potential of a range of other enzyme applications by qualitative means. Methods  LCA is used as analytical tool and modelling is facilitated in SimaPro software. Foreground LCA data are production/company specific and collected from P&P technology service providers, specific P&P companies and P&P researchers. The background data on energy systems, auxiliary chemicals, etc. are primarily taken from the ecoinvent database. Results  The study shows that fossil energy consumption and potential environmental impacts (global warming, acidification, nutrient enrichment, photochemical smog formation) induced by enzyme production are low compared with the impacts that they save when applied in bleach boosting, refining, pitch control, deinking, and stickies control. Discussion  The general explanation is that small amounts of enzyme provide the same function as large amounts of chemicals and that enzymatic processes generally require less fossil energy inputs than conventional processes. Data quality assessments and sensitivity analyses indicate that this observation is robust for all processes except deinking, although the results are subject to uncertainty and much variation. Conclusions and Recommendations  The environmental improvements that can be achieved by application of enzymatic solutions in the P&P industry are promising. To get a greater penetration of enzymatic solutions in the market and to harvest the environmental advantages of biotechnological inventions, it is recommended that enzymatic solutions should be given more attention in, for instance, ‘Best Available Technology’ notes within the framework of the European Directive on Integrated Pollution Prevention and Control (IPPC). ESS-Submission Editor: Roland Hischier (roland.hischier@empa.ch)     

The Sodium Hypochlorite Solution for the Removal of Lichen from Vertebrate Track Surfaces

The removal of extraneous biological materials from vertebrate ichnological specimens may be necessary if they have been exposed to subaerial processes in the field for long periods of time. It is not uncommon for fossil track specimens to be found nearly completely covered with lichen colonies, especially those recovered from alpine areas. This paper describes a technique using a sodium hypochlorite solution (bleach) to remove lichen from a track surface containing numerous avian prints and small theropod prints with skin impressions.