Robert Jeng

Lignocellulosic-based bio-refineries are essential for a secure energy in future. Lignin degradation is required for carbon recycling and production of renewable chemicals. Lignin due to the high level of color and low biodegradability, is categorized as a serious pollutant particularly in the aquatic ecosystem. In this study, biodegradation of org...

The mycelial growth ability of 13 white rot fungi were separately evaluated in kraft, organosolv, and soda black liquor agar-plates. The fungus able to best grow and decolorize black liquor agar-plates was grown in organosolv black liquor to investigate whether it reduced organosolv lignin molar mass. The fungus Bjerkandera adusta showed fair mycel...

This study was conducted to investigate the production of lignocellulolytic enzymes and sugars by the fungus Ganoderma lucidum during solid state fermentation (SSF) using primary sludge (PS) and wheat straw (WS) as substrates at different concentration ratios. For fungal growth on SSF, 20 g of each blended substrate was added to Erlenmeyer flasks,...

A novel modified thermoplastic starch is manufactured from a native starch using a polysaccharide produced by the fungus species Ophiostoma ulmi, by growing a culture in a yeast extract medium; adding the native starch; mixing, and harvesting the modified thermoplastic starch. The modified thermoplastic starch may be used in the manufacture of a bi...

Kraft pulping is the most commonly used pulping process in the pulp and paper industry. In this process wood chips are chemically delignified using sodium sulfide and sodium hydroxide. Delignification is usually followed by mechanical fiberization and a bleaching process of the resulting wood pulp. In addition to lignin-free wood pulp, this process...

A novel modified thermoplastic starch is manufactured from a native starch using a polysaccharide produced by the fungus species Ophiostoma ulmi, by growing a culture in a yeast extract medium; adding the native starch; mixing, and harvesting the modified thermoplastic starch. The modified thermoplastic starch may be used in the manufacture of a bi...

Soluble proteins were extracted from the vegetative cells of four pentose-fermenting yeasts, Candida shehatae, Pichia stipitis, R-1, and R-2, the R strains being of uncertain taxonomy, while the other two are culture collection yeasts. Isoenzyme patterns, protein patterns, and two-dimensional polypeptide mapping of these four strains were compared...

The presence of mansonones E and F in Ulmuspumila L. seedlings was determined 1, 2, 3, 5, 7, and 9 weeks after inoculation with aggressive and nonaggressive strains of Ophiostomaulmi (Buisman) Nannf. Mansonones E and F were accumulated in greater quantities by the seedlings inoculated with either strain than the seedlings inoculated with autoclaved...

Cultural characteristics and isoenzyme and soluble protein patterns on polyacrylamide gradient gels were compared in field isolates of the aggressive subgroup of Ophiostoma ulmi. Fourteen isolates were tested, 7 of the Eurasian race and 7 of the North American race. Values of fresh weight, dry weight, acetone powder weight, and water content of the...

Fungal culture filtrates, cytoplasm, and cell walls of Ophiostoma ulmi contain molecules that elicit mansonone (phytoalexin) accumulation in elm calli. The elicitors from nonaggressive isolate Q311 cause a more rapid reaction on bioassays than those from the aggressive isolate MH75. On the callus of a susceptible elm (Ulmus americana), the elicitor...

Two-dimensional polyacrylamide gel electrophoresis was used to identify and isolate a soluble polypeptide, the QP1 protein, which is characteristic of the vegetative hyphae of nonaggressive isolate Q412 of Ophiostoma ulmi. Individual QP1 spots were excised from 16 two-dimensional gels. Polypeptides were eluted from the gel spots by electroelution a...

Two-dimensional mycelial polypeptide maps were used to compare interspecific and intraspecific relationships among six isolates of Ophiostoma ulmi and four Eurasian and four North American race isolates of Ophiostoma novo-ulmi. The basic polypeptide pattern of O. ulmi differs markedly from that of O. novo-ulmi. A number of polypeptides were identif...

Isoenzyme and protein patterns of five isolates of Cryphonectria cubensis were determined by polyacrylamide gel electrophoresis. Differences in esterase, peroxidase, phosphoglucomutase, and hexokinase were detected between the Hawaiian (HW) isolate and the Brasilian (BR22) and African (AF100) isolates. These differences coincided with the virulence...

Alcohol extraction was made from seedlings of Ulmus americana L. first inoculated with either a nonaggressive or an aggressive strain of Ophiostoma ulmi (Buisman) Nannf. and cross-inoculated 2 weeks later. The content of mansonones A,C,E,F, and G, phytoalexins in U. americana, was determined weekly for 1–6 weeks after the first inoculation. Inocula...

Soluble mycelial proteins from Ophiostoma ulmi (Buism.) Nannf., the causal agent of Dutch elm disease, were separated by analytical electrofocusing and two-dimensional electrophoresis in polyacrylamide gels. Results showed the aggressive and nonaggressive strains of this pathogen each had about 60 Coomassie blue stained bands having isoelectric poi...

Starches modified by Ophiostoma spp. have been investigated to develop bio-materials with enhanced mechanical and physical properties for thermoplastic applications. In this study, glass transition temperature (Tg) of modified starches was investigated in both dynamic mechanical analyzer (DMA) and differential scanning calorimeter (DSC) to detect m...

Amylose containing polysaccharides are one of the most abundant and inexpensive naturally occurring biopolymers. Therefore, they are one of the most promising candidates to produce substitute plastics, especially in packaging applications. To determine the suitability for packaging applications, cytotoxicity of a modified amylose based bioplastic w...

Summary The intact yeast phase spores of Ophiostoma ulmi and O. novo-ulmi isolates were analysed by matrix-assisted-laser-desorption/ionization time-of-flight/time-of-flight mass spectrometry. The results clearly showed that isolates of O. ulmi and O. novo-ulmi have different mass peak profiles. The specific mass in m/z may vary slightly. One of th...

The accumulation of mansonones E and F in relation to susceptibility of elm to Dutch elm disease, caused by Ophiostoma ulmi, was investigated in callus cultures of Ulmus americana (susceptible), U. pumila (resistant), U. carpinifolia (intermediate resistant) and U. x 'Pioneer' (resistant). Callus cultures of each elm species were maintained on modi...

The thermal behavior of modified starches (MS) produced by biosynthetic pathway is described based on a comparative analysis with native starches (NS). MS were produced by fermentation in presence of Ophiostoma spp. cultures. Thermogravimetric analysis (TG) with successive derivatives (DTG) and differential scanning calorimetry (DSC) were used for...

The moisture absorption rate (MAR) and moisture desorption rate (MDR) are important for industrial coatings that request optimum tactile feel. One method is to include protein into the surface of the coating. It is important to understand the relationship between protein concentration and MAR-MDR. This research investigats the correlation between t...

Steady-state gene expression was compared between Dutch elm disease (DED)-susceptible Ulmus americana and DED-resistant U. pumila callus, leaf midrib, root and inner bark tissues. Stress-related cDNAs including phenylalanine ammonia-lyase (PAL), chitinase (CHT) and polygalacturonase-inhibiting protein (PGIP) were isolated and compared following RT-...

This study examined in vivo gene expression associated with the colonization of Dutch elm disease-susceptible Ulmus americana by H175, an aggressive strain of Ophiostoma novo-ulmi Brasier. Stress-related genes encoding phenylalanine ammonia-lyase (PAL), chitinase (CHT) and polygalacturonase inhibiting protein (PGIP) were used to observe gene expres...

Lipids and their fatty acids from the mycelia of aggressive and non-aggressive strains of Ceratocystis ulmi were examined at different incubation temperature. The quantity and degree of fatty acid unsaturation were correlated with the pathogenicity of the fungus.

This paper reports the differential accumulation of inhibitory compounds in American elm seedlings after inoculation with a non-aggressive and an aggressive strain of C, ulmi.

Six mansonoes, previously isolated from Ulmus americana L. infected by Ceratocystis ulmi (Buis.) C. Moreau, were assayed for their inhibitory activity against several strains of the fungus. Mansonone A was most effective in inhibiting the linear growth of six strains of C. ulmi tested. A mixture of the pure mansonones, recombined at their original...

The toxic effect of elm phytoalexins (mansonones) on two isolates of Ophiostoma ulmiwas studied cytologically and physiologically. The effects included increasing ion leakage, reducing respiration rate and altering the structure of cellular organelles.

A correlation between amino acid utilization and pathogenicity among five strains of Ceratocystis ulmi (Buis.) Moreau has been observed. Conditioning inoculation with a non-aggressive strain of C. ulmi rendered white elm seedlings resistant to further attack by an aggressive strain of the same pathogen.

This paper describes the chemical and biochemical properties of exopolysaccharides (EPS) produced by Ophiostoma ulmi and O. novo-ulmi isolates, the Dutch elm disease (DED) fungi. Some of EPS have been considered as pathogenicity factor in the DED complex. The selected isolates grow well and produce EPS in a medium containing various types of carbon...

Microbial modification of starch with Ophiostoma spp. was investigated, with the purpose of developing a novel packaging material for the food or pharmaceutical industries. Various starch sources, such as tapioca, potato, corn, rice and amylopectin were tested as raw materials. The initial screening demonstrated that tapioca and potato starch had b...

The identification of Gram-negative pathogenic and non-pathogenic bacteria commonly isolated from an orchard phylloplane may result in a time consuming and tedious process for the plant pathologist. The paper provides a simple "one-step" protocol that uses the polymerase chain reaction (PCR) to amplify intergenic spacer regions between 16S and 23S...

Isolates of Cylindrocladium floridanum obtained from diseased roots of white and black spruce seedlings and surrounding soil in bareroot nurseries in Ontario, Minnesota and Wisconsin area were compared by mitochondrial DNA (mtDNA) and ribosomal DNA (rDNA) restriction fragment length polymorphisms (RFLPs), human minisatellite DNA fingerprints and po...

Eighteen isolates representing six Fusarium species from diverse hosts and geographical origins were evaluated to determine ribosomal DNA variation using polymerase chain reaction and restriction fragment length polymorphisms. No length variation was observed for amplified 18S and 28S regions. However, amplification of the ITS region showed one iso...

This study examined the polymerase chain reaction (PCR) amplified internal transcribed spacer (ITS) and 26S ribosomal DNA (rDNA) regions of 15 entomopathogenic nematode isolates including Steinernema feltiae syn. bibionis, S. glaseri, seven strains of S. carpocapsae, four strains of Heterorhabditis bacteriophora, and two field isolates. RDNA length...

Little genetic information exists comparing aggressive and non-aggressive isolates of the causal agent of Dutch elm disease, Ophiostoma ulmi. Two genetic elements were compared between the subgroups. The ceratoulmin cu gene product has been associated with disease symptoms. Nucleotide-sequence analysis of cu and the internal transcribed spacer (ITS...

Restriction fragment length polymorphisms from PCR amplified ribosomal DNAs of three Trichogramma species, T. minutum, T. brassicae, and T. near sibiricum, were studied. Length variation in the internal transcribed spacer (ITS) region was observed. The ITS region of T. brassicae is about 1350 base pairs (bp) in length and those of T. minutum and T....

The hydrophobic protein cerato-ulmin (CU), produced by Ophiostoma ulmi, has been implicated in the pathogenicity of this fungus on elm. Primers were designed based on the nucleotide sequence deduced from the published CU amino-acid sequence, and a DNA fragment of the cu gene was amplified using the polymerase chain reaction. The amplified cu fragme...

A 21 kDa glycoprotein, identified as a mansonone-inducing elicitor on elm callus, was purified from culture filtrates of Ophiostoma ulmi using HPLC ion-exchange chromatography. Both aggressive and non-aggressive isolates of O. ulmi yielded this elicitor. The glycoprotein is composed of 19 different amino acids and has a 17–20% carbohydrate content,...

Mansonone F (phytoalexin) production in elm callus induced by elicitors of Ophiostoma ulmi is affLited by cultural and experimental conditions. These factors include different fun gal isolates, fungal culture age, elicitor concentration, the time of elicitor treatment, the callus cu Ytured with or without light and the callus subculturing frequency...

The natural population structure of the Dutch elm pathogen Ophiostoma ulmi was determined from isolated collected from across a Western Canadian disease front through an analysis of restriction-site polymorphisms in the ribosomal DNA repeat, length mutations in the mitochondrial genomes, and through DNA fingerprinting of the nuclear genomes using a...

The xylem of woody angiosperms comprises the great majority of the biomass on earth (Lieth and Whittaker 1975, Woodwell et al. 1978, Duchesne and Larson 1989). Understandably, a wide array of living organisms have evolved mechanisms to acquire and metabolize the different components of tree xylem. On the other hand, the xylem of trees is critical f...

Three genetically distinct populations of the Dutch elm pathogenOphistoma ulmi within the aggressive subgroup were defined by the hybridization of a human minisatellite DNA sequence (HVR 33.6) to polymorphic dispersed DNA sequences within theO. ulmi nuclear genomes. For the 10 isolates examined there was a close correlation between nuclear DNA fing...

Mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) of 12 aggressive and 6 non-aggressive isolates of Ophiostoma ulmi (Buism.) Nannf. from 6 countries were investigated. Mitochondrial DNAs from O. ulmi budding cells were isolated by bisbenzimide-Cesium Chloride buoyant density centrifugation, digested using either of the res...

The accumulation of mansonones E and F was investigated in Ulmus americana L. seedlings 5 weeks after inoculation with three aggressive and three non-aggressive isolates of Ophiostoma ulmi (Buism.) Nannf. The three non-aggressive isolates stimulated significantly more mansonone E and F accumulation than the three aggressive isolates of O. ulmi. Man...

Mansonones A and C to G, sesquiterpene quinones possessing antifungal properties, were isolated from the elmUlmus americana infected withCeratocystis ulmi. Scopoletin and -sitosterol were also present in the extracts. The mansonones were not detected on chromatographic analysis of extracts from healthy elm tissue. The extent to which these antifung...

Variability in virulence were detected among geographic isolates of Cryphonectria.cubensis (Bruner) Hodges. Inoculation studies of isolates, originally cultured from Brazil, Africa and Hawaii, in provenance of Eucalyptus pellita F. Muell (resistant) and E. saligna Sm. (susceptible) showed that the variation in resistance of Eucalyptus spp. is quant...

The fine structure of ascogonium, ascogenous hyphae and subsequent ascosporogenesis in Ceratocystis ulmi are studied with electron microscopy. The findings are compared and discussed with those reports on other Ascomycetes.

Transmission electron microscopic observations of C. ulmi show that there are three distinct types of the hyphae and three distinct layers forming the nscocarp peridium. The cellular organelles of the hyphae and ascocarp peridial layers are described.