Aromatic Substances Inhibiting Wheat Powdery Mildew Produced by a Fungus Detected with a New Screening Method for Phylloplane Fungi

Microorganisms isolated from wheat leaf surfaces were screened for inhibition of wheat powdery mildew. A new screening method, in which wheat leaves were inoculated with Blumeria graminis f. sp. tritici and incubated with the cultured microorganisms under non-contact conditions, was developed in the present study. Using this method, 10 phylloplane fungi that inhibited wheat powdery mildew were selected from 408 microorganisms isolated from wheat leaf surfaces. Among these 10 strains, a fungus designated as Kyu-W63 had an especially strong inhibitory effect. Kyu-W63 produced white colonies without spores when cultivated on PDA. Kyu-W63 had a strong aromatic odor when being cultured. Wheat powdery mildew was suppressed even though a membrane filter with a pore size of 0.45 μm was placed between the mycelial colony and wheat leaf segment. However, when activated charcoal was introduced, Kyu-W63 did not inhibit growth of B. graminis. It was presumed that volatile substances were involved in the inhibitory effect of Kyu-W63. GC-MS analysis was used to identify two substances produced by Kyu-W63 with molecular weights of 164 and 166. Kyu-W63 also inhibited the in vitro growth of four plant pathogenic fungi other than B. graminis. Received 19 September 2001/ Accepted in revised form 7 February 2002     

Reduced mitotic activity and increased apoptosis of fetal sertoli cells in rat hypogonadic (hgn/hgn) testes

Sterility in male hypogonadic (hgn/hgn) rats results from congenital testicular dysplasia caused by a single recessive gene hgn on rat chromosome 10. We recently identified an insertion mutation in the Spag5/astrin gene of hgn/hgn rats that may cause defective proliferation of immature Sertoli cells in the postnatal hgn/hgn testis. Since the pathological alterations were present in the testes at birth, we examined the involvement of defective mitosis and apoptotic cell death in embryonic development of hgn/hgn testes. Testicular hypoplasia was apparent at embryonic day (ED) 18.5. Immunostaining of hgn/hgn testes at ED 21.5 with antibody to GATA-4, which is specific for fetal Sertoli cells in the seminiferous cords, showed that the significant decrease in the number of fetal Sertoli cells was accompanied by a two fold increase in their mitotic index and abnormal mitosis and apoptosis. Prior to this, we observed a decrease in the number of BrdU-labeled cells, an increase in the number of TUNEL-positive apoptotic cells, and presence of MIS-positive apoptotic cells in hgn/hgn testes on ED 17.5 and 18.5. These results suggest that the Spag5 mutation may cause a reduction in mitotic activity and an increase in apoptosis of fetal Sertoli cells in hgn/hgn testes.     

Campylobacter

Species within the genus, Campylobacter, have emerged over the last three decades as significant clinical pathogens, particularly of human public health concern, where the majority of acute bacterial enteritis in the Western world is due to these organisms. Of particular concern are the species, C. jejuni and C. coli, which are responsible for most of these gastrointestinal-related infections. Although these organisms have already emerged as causative agents of zoonoses, several aspects of their epidemiology and pathophysiology are only beginning to emerge. Trends in increasing antibiotic resistance are beginning to emerge with oral antibiotics, which may be the drug of choice for when it is necessary to intervene chemotherapeutically. This review wishes to examine (i) emerging clinical aspects of the disease, such as Guillain Barre syndrome (GBS), (ii) the association between these organisms and poultry as a natural host, (iii) environmental aspects of Campylobacter epidemiology, (iv) the emergence of atypical campylobacters (v) emerging trends in antibiotic resistance, (vi) adoption of modern methods for the detection of campylobacters.     

Antifungal substances produced by fungal strain Kyu-W63 from wheat leaf and its taxonomic position

Fungal strain Kyu-W63 from a wheat leaf suppressed the development of wheat powdery mildew caused by Blumeria graminis f. sp. tritici. Nuclear magnetic resonance analysis revealed that Kyu-W63 produced two volatile substances: 5-pentyl-2-furaldehyde and 5-(4-pentenyl)-2-furaldehyde. Although the two are known to be nematicidal substances, the antifungal activity of 5-(4-pentenyl)-2-furaldehyde was first confirmed in the present study. Culture experiments revealed that synthesized 5-pentyl-2-furaldehyde had antifungal activity against three other pathogens – Fusarium oxysporum f. sp. lycopersici, Colletotrichum fragariae, Botrytis cinerea – with a minimum inhibitory concentration of 2–4µg/ml. The two fractionated substances were also inhibitory against C. fragariae. Because the absence of spores in strain Kyu-W63 made its identification difficult, the sequence in the rDNA internal transcribed spacer (ITS) region of Kyu-W63 was compared with that of Irpex lacteus, which is known to produce these substances. Strain Kyu-W63 completely agreed with I. lacteus in terms of the ITS sequences, so strain Kyu-W63 was inferred to be I. lacteus. Two other strains of I. lacteus tested also produced the two furaldehydes and suppressed the growth of F. oxysporum f. sp. lycopersici. Both Kyu-W63 and additional strains produced the two furaldehydes on potato dextrose agar but not on water agar.The nucleotide sequence data reported are available in the DDBJ databases under accession numbers AB079264, AB079265, AB079266, and AB079267     

Carbon nanotubes with temperature-invariant viscoelasticity from -196 degrees to 1000 degrees C

Viscoelasticity describes the ability of a material to possess both elasticity and viscosity. Viscoelastic materials, such as rubbers, possess a limited operational temperature range (for example, for silicone rubber it is -55° to 300°C), above which the material breaks down and below which the material undergoes a glass transition and hardens. We created a viscoelastic material composed from a random network of long interconnected carbon nanotubes that exhibited an operational temperature range from -196° to 1000°C. The storage and loss moduli, frequency stability, reversible deformation level, and fatigue resistance were invariant from -140° to 600°C. We interpret that the thermal stability stems from energy dissipation through the zipping and unzipping of carbon nanotubes at contacts.     

Effects of cyclophosphamide on the kaolin consumption (pica behavior) in five strains of adult male rats

It is known that pica, the consumption of non-nutritive substances such as kaolin, can be induced by administration of toxins or emetic agents in rats. In the present study, we examined the effects of intraperitoneal (i.p.) administration of cyclophosphamide on pica behavior and on the concentration of 5-hydroxyindoleacetic acids (5HIAA) in cerebrospinal fluid (CSF) in the following five strains of adult male rats: Sprague Dawley (SD), Wistar, Fischer 344 (F344), Wistar-Imamichi (WI) and Long Evans (LE). Cyclophosphamide (25 mg or 50 mg/kg) was injected (i.p.) into the rats and kaolin and food intake were measured at 24 hr after injection. The animals were anesthetized with urethane (1 g/kg) at 3 hr after injection of cyclophosphamide, and CSF was collected from the cisterna magna. WI and LE rats clearly showed pica behavior as compared with the other strains. In LE rats, the concentration of 5HIAA in CSF also increased in a dose-dependent manner of cyclophosphamide. The pretreatment with ondansetron (5-HT(3) antagonist) restored both changes (kaolin consumption and 5HIAA levels) induced by cyclophosphamide. These results suggest that the LE rat is sensitive to cyclophosphamide, that pica induced by cyclophosphamide mimics many aspects of emesis including the serotonergic response in the central nervous system and that use of the pica model would be a practical method for evaluating the effects of antiemetic drugs in addition to the mechanism of emesis.     

The cumulative methane production from dairy cattle slurry can be explained by its volatile solid,temperature and length of storage

In order to refine the national estimate of methane emission from stored cattle slurry, it is important to comprehend the basic characteristics of methane production. Two dairy cattle slurries were obtained from livestock farms located in Hokkaido (a northern island) and Kyushu (a southern island). The slurries were diluted with water into three levels: undiluted, three times diluted, and 10 times diluted. Three hundred mL of the slurries were put into a bottle with a headspace volume of 2.0 L, which was filled with nitrogen gas and then sealed by butyl rubber. Four levels of temperature were used for incubation: 35, 25, 15 and 5 °C. The time course of the cumulative methane production per volatile solid (VS) was satisfactorily expressed by an asymptotic regression model. The effect of dilution on the methane production per VS was not distinctive, but that of temperature was of primary importance. In particular, higher temperature yields a higher potential production and a shorter time when the cumulative production reaches half of the potential production. The inclusive and simple models obtained in this study indicate that the cumulative methane production from stored cattle slurry can be explained by VS, temperature and length of storage.