Enzymatic saccharification of spent wood-meal media made of 5 different tree species after cultivation of edible mushroom <Emphasis Type="Italic">Auricularia polytricha</Emphasis>

The chemical characteristics and the suitability for enzymatic saccharification in the spent culture media (SCM) of Auricularia polytricha were examined in order to investigate the utilization of the SCM as a biomass resource for alternative energy production. Wood meals from 3 hardwood species (Quercus serrata, Betula platyphylla var. japonica, and Alnus japonica) and 2 softwood species (Pinus densiflora and Cryptomeria japonica) were used as basal culture media. Dry weight of fruiting bodies were higher in the cultural media made of B. platphylla var. japonica and A. japonica. Amount of weight loss in media showed almost the same value among the cultural media made of 5 species, except for media made of C. japonica. The amounts of the main chemical components (Klason lignin, holocellulose, and α-cellulose) in SCM showed lower values than those in wood meals (WM) and fresh media (FM). After saccharification of the media by Meiselase for 48 h, the hydrolysis weight decrease dramatically increased in SCM. The amount of glucose in SCM ranged from 10.9 to 19.2 g/100 g dry biomass. The highest amount of glucose was obtained in the SCM from B. platyphylla var. japonica. These results indicate that SCM of A. polytricha is a suitable biomass material to produce fermentable sugars for bio-ethanol production.     

Cloning of nicotianamine synthase genes from Arabidopsis thaliana

Nicotianamine synthase (NAS) catalyzes the trimerization of S-adenosylmethionine to form one molecule of nicotianamine (NA). NA is present in all the plants; it chelates metal cations, and is considered to play a role in metal homeostasis in plants. Moreover, in graminaceous monocotyledonous plants, NA is an essential intermediate in the biosynthesis of mugineic acid family phytosiderophores (MAs). In order to identify the gene encoding NAS in dicotyledonous plants, Arabidopsis thaliana databases were searched using the nucleotide sequence of the NAS gene from barley (HvNAS), which we have recently isolated. We found several ESTs and three genomic sequences highly homologous to HvNAS in the databases. Based on these nucleotide sequences and that of HvNAS, we designed 2 sets of primers to isolate the NAS orthologues in Arabidopsis and succeeded in obtaining three DNA clones encoding AtNAS (AtNAS1, 2, and 3). These clones were expressed in Escherichia coli and their protein products displayed the NAS activity. The expression of AtNASl was detected in both shoots and roots of A. thaliana by RT-PCR; AtNAS3 expression was only detected in the shoots. In contrast, AtNAS2 expression was not detected in any organs.     

Stress-wave velocity of trees and dynamic Young’s modulus of logs of 4-year-old Eucalyptus camaldulensis trees selected for pulpwood production in Thailand

Eucalyptus camaldulensis Dehnh. is extensively planted in Thailand to produce wood chips used as raw material for pulp and paper. To promote the utilization of the wood from plantation-grown E. camaldulensis for solid lumber, stress-wave velocity of trees and dynamic Young’s modulus of logs were investigated for 4-year-old trees of eight half-sib families selected for pulpwood production on the basis of the growth characteristics in the previous tree breeding program. For the eight families, the mean stem diameter at 1.3 m above ground level and mean tree height were 7.6 cm and 11.9 m, respectively. The mean stress-wave velocity of eight families was 3.45 km/s. Dynamic Young’s modulus of logs ranged from 7.88 to 17.64 GPa, and the mean value for the eight families was 11.72 GPa. Stress-wave velocity of trees was significantly correlated with dynamic Young’s modulus of logs, suggesting that dynamic Young’s modulus of wood can be evaluated nondestructively by stress-wave velocity of trees. Significant differences in stress-wave velocity and dynamic Young’s modulus of logs were obtained among families. Thus, to promote the utilization of E. camaldulensis wood for solid lumber production, selection of trees with high Young’s modulus should be applied to trees already selected for the growth characteristics in the previous tree breeding program.     

Variation in tree growth characteristics, stress-wave velocity, and Pilodyn penetration of 24-year-old teak (Tectona grandis) trees originating in 21 seed provenances planted in Indonesia

Growth characteristics [stem diameter (D), tree height (H), and bole volume (V)], stress-wave velocity (SWV), and Pilodyn penetration (P) were measured for 21 seed provenances of 24-year-old teak trees planted in Indonesia to characterize variation in tree growth characteristics, SWV, and P among seed provenances. Broad-sense heritability and correlations between the measured characteristics were also determined. Significant differences for all measured characteristics were observed among provenances, indicating that these characteristics are genetically controlled. Broad-sense heritabilities of growth characteristics, SWV, and P are moderate values. These results indicate potential for improving growth characteristics and wood properties of teak trees with the help of breeding programs. Highly significant positive correlations were observed among the growth characteristics, suggesting that they are closely related. In contrast, no significant correlations were observed between the growth characteristics and SWV, indicating that they are independent. We conclude that mechanical properties are also important criteria for selecting plus trees in tree breeding programs. Principal component analysis revealed that seed provenances from Indonesia (Bangilan, Deling, and Randublatung) and India (Malabar and Central Province) have high scores of growth characteristics and SWV.     

Virulence of Raffaelea quercivora isolates inoculated into Quercus serrata logs and Q. crispula saplings

This study was conducted to compare the virulences of various isolates of Raffaelea quercivora—a fungus that causes Japanese oak wilt disease—towards Japanese oak trees. Five isolates were collected from a wide range of Japan and inoculated into Quercus serrata logs and Q. crispula saplings. The tangential length of the discolored sapwood in the Q. serrata logs differed significantly among the isolates. The trend in isolate virulence was similar for the Q. serrata logs and the Q. crispula saplings. This is the first report suggesting that there is variability in virulence among isolates of R. quercivora.     

No evidence of horizontal infection in horses kept in close contact with dogs experimentally infected with canine influenza A virus (H3N8)

Background

Since equine influenza A virus (H3N8) was transmitted to dogs in the United States in 2004, the causative virus, which is called canine influenza A virus (CIV), has become widespread in dogs. To date, it has remained unclear whether or not CIV-infected dogs could transmit CIV to horses. To address this, we tested whether or not close contact between horses and dogs experimentally infected with CIV would result in its interspecies transmission.

Methods

Three pairs of animals consisting of a dog inoculated with CIV (10^8.3 egg infectious dose₅₀/dog) and a healthy horse were kept together in individual stalls for 15 consecutive days. During the study, all the dogs and horses were clinically observed. Virus titres in nasal swab extracts and serological responses were also evaluated. In addition, all the animals were subjected to a gross pathological examination after euthanasia.

Results

All three dogs inoculated with CIV exhibited clinical signs including, pyrexia, cough, nasal discharge, virus shedding and seroconversion. Gross pathology revealed lung consolidations in all the dogs, and Streptococcus equi subsp. zooepidemicus was isolated from the lesions. Meanwhile, none of the paired horses showed any clinical signs, virus shedding or seroconversion. Moreover, gross pathology revealed no lesions in the respiratory tracts including the lungs of the horses.

Conclusions

These findings may indicate that a single dog infected with CIV is not sufficient to constitute a source of CIV infection in horses.     

Evaluation of right ventricular Tei index (index of myocardial performance) in healthy dogs and dogs with tricuspid regurgitation

Right ventricular (RV) Tei index (index of myocardial performance) has been demonstrated to be clinically useful in estimating RV function in various human cardiac diseases. The purposes of this study were to validate the correlation between RV Tei index and RV function obtained by cardiac catheterization in healthy dogs, and to evaluate the RV Tei index in dogs with tricuspid regurgitation (TR). In healthy dogs, the RV Tei index significantly correlated with the RV peak +dP/dt (r=-0.80, p<0.0001) and -dP/dt (r=0.69, p=0.0001). In normal dogs, the RV Tei index was not significantly correlated with heart rate, body weight, and age. The RV Tei index significantly increased in dogs with moderate to severe TR (0.39 +/- 0.35, p=0.0015), filariasis (0.46 +/- 0.16, p=0.0131), and trivial to mild TR and severe mitral regurgitation (MR; 0.61 +/- 0.14, p=0.0017) when compared with the normal dogs (0.17 +/- 0.10). In addition, the RV Tei index in dogs with TR significantly increased in association with pulmonary hypertension [PH(-), 0.19 +/- 0.09; PH(+), 0.65 +/- 0.14; respectively p<0.0001]. Our study has demonstrated that RV Tei index is a feasible approach to estimate RV function in dogs and is not influenced by heart rate, body weight, and aging. Further investigations are required to clarify the clinical significance of RV Tei index in dogs with right-sided cardiac diseases.     

The aerobic bacterial flora of the middle and external ears in normal dogs

The aerobic bacterial flora of the middle and external ears was elucidated in 30 normal dogs (60 ears). Bacterial swab samples were obtained by rubbing the surface of the tympanic cavity and external ear canal. In the middle ear, bacteria were cultured from 48 per cent of the total ears and mainly included Escherichia coli (8 per cent), yeasts (8 per cent), staphylococci (7 per cent) and branhamella (7 per cent). In the external ear, bacteria were found in 46 per cent of the total ears and staphylococci (19 per cent) and yeasts (7 per cent) were the main isolates. Mycoplasma was found in one external ear sample, but in no middle ear samples in an examination of 20 ears. The same type of bacterium was hardly ever found in both the middle and external parts of each ear.     

Involvement of carbon catabolite repression on regulation of endopolygalacturonase gene expression in citrus fruit

 The Acpg1 gene of Alternaria citri encodes an extracellular endopolygalacturonase that is important for virulence in citrus fruits. Expression of Acpg1 is regulated by substrate induction and carbon catabolite repression. A green fluorescent protein (GFP) gene was employed as a reporter gene to define 813 bases upstream of the translation start site comprising the Acpg1 promoter. This upstream sequence contains five putative binding sequences of catabolite repressive element A (CreA), a cis-acting zinc finger repressor involved in carbon catabolite repression. We constructed each CreA-binding site-deleted Acpg1 promoters with GFP reporter gene and transformed them to A. citri. The construct PGPDL4 deleted from −401 to −813 showed both substrate induction and catabolite repression, whereas PGPDL5 additionally deleted from −1 to −84, including one putative CreA-binding site, resulted in a loss of catabolite repression function. Green fluorescence of PGPDL4 was induced by pectin in the peel but was repressed completely in the juice sac area of citrus fruit. However, green fluorescence of PGPDL5 was induced in both the peel and juice sac area, indicating that repression of Acpg1 in the juice sac area is likely accomplished by carbon catabolite repression. Received: October 4, 2002 / Accepted: October 31, 2002 Acknowledgments The authors thank Drs. D. Cullen, A. Van den Wymelenberg, and J. Andrews, University of Wisconsin, for providing pTEFEGFP containing GFP and Dr. T. Tsuge, Nagoya University, for providing transformation vector pSH75. The nucleotide sequence data of Acpg1 promoter region in the DDBJ, EMBL, and GenBank sequence databases is under accession number AB047543. This research was supported in part by grants to K.A. from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.