Pneumonia in horses induced by intrapulmonary inoculation of Streptococcus equi subsp. zooepidemicus

To evaluate the possibility that Streptococcus equi subsp. zooepidemicus (S.z) the causative bacterial agent of equine shipping fever pneumonia (ESFP), as well as to investigate its pathogenesis, 10 horses (seven Thoroughbreds and three Anglo-Arab species, ranging from 2-4 years in age) were experimentally inoculated, via an endoscope, into bronchus of the lung lobe with a dose of 30 ml of 1-7 x 10(8) CFU/ml of S.z. After inoculation, autopsy and pathological examinations were sequentially conducted 30 min, 1, 2, 3, 4, 17, 20 hr and 2 weeks later. Pneumonia induced by the intrapulmonary inoculation of S.z was characterized by small purulent pneumonic foci in the inoculated areas. With the lapse of time, these foci developed into serous hemorrhagic pneumonia, hemorrhagic purulent pneumonia, and then purulent, coagulation necrotic pneumonia. These pathomorphological characteristics of experimental pneumonia closely resemble those naturally occurring ESFP. There is strong evidence that S.z. is implicated as a causal factor in ESFP. S.z. grew in the mucus, exudate, and pulmonary effusions. Further, the bacteria showed resistance against phagocytosis by pulmonary alveolar macrophages (PAM) and neutrophils. Inhibition of PAM and neutrophil function is considered to be important in the development of pneumonia. With the progression of the disease, the neutrophils often adhered to the endothelial surface of the alveolar capillary lumen and played a role in generating coagulation necrosis of lung tissues.     

Inhibition of mitogen activated protein kinase activity induces parthenogenetic activation and increases cyclin B accumulation during porcine oocyte maturation

The inhibition of mitogen activated protein kinase (MAPK) activation during porcine oocyte maturation leads to decreased maturation promoting factor (MPF) activity and to the induction of parthenogenetic activation. In the present study, in order to analyze the mechanism underlying the suppression of MPF activity in MAPK-inhibited porcine oocytes, we injected mRNA of SASA-MEK, a dominant negative MAPK kinase, or antisense RNA of c-mos, a MAPK kinase kinase, into immature porcine oocyte cytoplasm. The injection of SASA-MEK mRNA or c-mos antisense RNA inhibited the MAPK activity partially or completely, respectively, decreased the MPF activity slightly or significantly, respectively, and induced parthenogenetic activation in 17.1% or 96.6% of mature oocytes, respectively, although no parthenogenetic activation was observed in the control oocytes. Immunoblotting experiments revealed that cyclin B accumulation in these MAPK-suppressed porcine oocytes was increased significantly after 50 h of culture and that a considerable amount of MPF was converted into inactive pre-MPF by hyperphosphorylation. These results indicate that the inhibition of MAPK activity in porcine oocytes did not promote cyclin B degradation but rather suppressed it; also the decrease in MPF activity in MAPK-suppressed porcine oocytes correlated with the conversion of active MPF into inactive pre-MPF.     

Enhancement of chicken resistance against Escherichia coli infection by oral administration of Bifidobacterium thermophilum preparations

Three types of Bifidobacterium thermophilum extract were prepared and fed to 2-wk-old chickens to evaluate their usefulness in enhancing the defense activity of the chickens against pathogenic Escherichia coli. All three preparations resulted in significant reduction (P < 0.05) of E. coli numbers in the lungs of the treated chicken groups compared with the control nontreated group. Besides, improvement in the survival rate was observed in the treated chicken groups, especially the one administered the enzyme-digested B. thermophilum extract sample. Concanavalin A-stimulated lymphocytes from the latter group demonstrated significantly higher proliferation activity compared with those from the control group. These results suggest that oral administration of B. thermophilum preparations may be used to enhance the resistance of chickens against E. coli infection.     

Laccase Gene LAC1 of Colletotrichum lagenarium Is Not Essential for Melanin Biosynthesis and Pathogenicity

Laccase has been shown to oxidize 1,8-dihydroxynaphthalene (1,8-DHN) in the final step of melanin biosynthesis in several fungi. In this study, a laccase gene (LAC1) was cloned from Colletotrichum lagenarium that synthesizes 1,8-DHN melanin, and characterized. To clone the LAC1 sequences, genomic DNA was subject to polymerase chain reactions (PCR) with degenerate oligonucleotide primers that were designed on the basis of amino acid sequences conserved among characterized laccases from other ascomycetes Botrytis cinerea, Neurospora crassa, Aspergillus nidulans, and Cryphonectria parasiticus. The LAC1 gene contained an open reading frame composed of 589 codons and three introns of 51, 49, and 57 nucleotides. The deduced amino acid sequence of Lac1p had high similarity to that of laccase from N. crassa and significant homology with those of multicopper blue proteins. Under melanin-induced culture of this fungus, laccase activity significantly increased and LAC1 expression was also detected. However, the lac1Δ mutants retained laccase activity and had no significant phenotypic differences in melanin production or pathogenicity from the wild-type strain. Received 23 February 2001/ Accepted in revised form 29 March 2001     

Epistatic effects between pairs of the growth hormone secretagogue receptor 1a,growth hormone,growth hormone receptor,non‐SMC condensin I complex,subunit G and stearoyl‐CoA desaturase genes on carcass,price‐related and fatty acid composition traits in Japanese Black cattle

Growth hormone secretagogue receptor 1a (GHSR1a), growth hormone (GH), growth hormone receptor (GHR), non‐SMC condensin I complex, subunit G (NCAPG) and stearoyl‐CoA desaturase (SCD), are known to play important roles in growth and lipid metabolisms. Single and epistatic effects of the five genes on carcass, price‐related and fatty acid (FA) composition traits were analyzed in a commercial Japanese Black cattle population of Ibaraki Prefecture. A total of 650 steers and 116 heifers for carcass and price‐related traits, and 158 steers for FA composition traits were used in this study. Epistatic effects between pairs of the five genes were found in several traits. Alleles showing strain‐specific differences in the five genes had significant single and epistatic effects in some traits. The data suggest that a TG‐repeat polymorphism of the GHSR1a.5′UTR‐(TG)_n locus plays a central role in gene–gene epistatic interaction of FA composition traits in the adipose tissue of Japanese Black cattle.     

Isolation of Streptobacillus moniliformis from a pet rat

We isolated Streptobacillus moniliformis, the causative agent of rat-bite fever in humans, from the salivary gland of a pet rat postmortem. The isolate was a Gram-negative pleomorphic coccobacillus, which produced acid from glucose and showed enzymatic activities for eight items in the API ZYM system. The results were consistent with those of the reference strain, ATCC 14647(T), except for acid production from dextrin. Partial sequencing of 16S rRNA (1,440 bp) and gyrB genes (514 bp) of the isolate revealed similarities of 100% and 99.8%, respectively, to those of S. moniliformis in GenBank. Therefore, the isolate was identified as S. moniliformis. These results suggested the potential risk of rat-bite fever arising from pet rats in Japan.     

Bacillus cereus from the environment is genetically related to the highly pathogenic B. cereus in Zambia

To follow-up anthrax in Zambia since the outbreak in 2011, we have collected samples from the environment and the carcasses of anthrax-suspected animals, and have tried to isolate Bacillus anthracis. In the process of identification of B. anthracis, we collected two isolates, of which colonies were similar to B. anthracis; however, from the results of identification using the molecular-based methods, two isolates were genetically related to the highly pathogenic B. cereus, of which clinical manifestation is severe and fatal (e.g., pneumonia). In this study, we showed the existence of bacteria suspected to be highly pathogenic B. cereus in Zambia, indicating the possibility of an outbreak caused by highly pathogenic B. cereus.     

Effects of stand density on the productivity ofCryptomeria japonica male flowers

We have studied male flower production and relative illumination in clonal sugi (Cryptomeria japonica) forests planted at densities of 1,500/ha, 3,000/ha, and 5,000/ha, to clarify the effects of forest management on male flower production. Both the relative illumination and male flower production decrease as the stand density increases. The lowest position at which male flowers are formed decreases as the density of the stand decreases. High thinning intensity promotes male flower production and light pruning is ineffective to reduce male flower production. Therefore, traditional management methods used in sugi forests (i.e. planting at high density, frequent light thinning, intensive pruning and short rotation) are ideal strategies for limiting male flower production.     

Inheritance of the trait of male sterility inCryptomeria japonica

Matings of male-sterileC. japonica and fertile eliteC. japonica, as well as backcross seedlings of male-sterile trees, were carried out to clarify the genetic trait of male sterility of theC. japonica. The seeds from male-sterileC. japonica were germinated in an incubator and grown them in the greenhouse between 1994 and 1997. The seedlings were treated with 100 ppm gibberellin at early July 1994 and early July 1995 to promote the formation of male flowers. In the middle of January 1995, the male flowers of all seedlings were examined under the microscope to confirm the production of pollen. In January 1996, pollen did not developed in to the male flowers from the seedlings between the fertiled elite and backcrossC. japonica. In January 1997, all seedlings of eliteC. japonica produced pollen in their male flowers; however, pollen did not developed in 55 out of 120 backcrossed seedlings. This evidence suggests that the heredity pattern of male sterility inC. japonica is nuclear male sterility controlled by a pair of recessive genes.