Shigeo Namioka

The inhibitory effects of oligonucleotides, complementary to Marek's disease virus mRNA transcribed from the BamHI-H region, on the proliferation of transformed lymphoblastoid cells, MDCC-MSB1.

An oligonucleotide complementary to the splice donor sequence of the 1.8 kb gene family produced from the BamHI-H region of Mareks disease virus (MDV) DNA inhibited the proliferation of the MDV-derived lymphoblastoid cell line, MDCC-MSB1 (MSB-1), but not that of the avian lymphoid leukosis-derived lymphoblastoid cell line, LSCC-BK3. Colony formation in soft agar was also inhibited by treatment of MSB-1 cells with the antisense oligonucleotide. It is hypothesized that expression of the 1.8 kb gene family produced from the BamHI-H region is directly associated with the maintenance of the tumorigenic state of transformed Mareks disease-derived lymphoblastoid cells.

A high frequency of induction of chromosome aberrations in the bone marrow cells of LEC strain rats by X-irradiation

LEC strain rats, which have been known to develop hereditarily spontaneous fulminant hepatitis 4 to 5 months after birth, are highly sensitive to whole-body X-irradiation when compared to WKAH strain rats. The present results showed that the frequencies of all types of chromosome aberrations induced by X-irradiation in the bone marrow cells of LEC rats were approximately 2- to 3-fold higher than those of WKAH rats, though no significant difference was observed in the frequency of spontaneous chromosome aberrations between LEC and WKAH rats.

Chapter X Pasteurella multocida---Biochemical Characteristics and Serotypes

Publisher Summary Pasteurella multocida , the organism that is pathogenic for various animals and fowls, can be divided into more than 15 serotypes. Certain serotypes are host specific while others are not. Consequently, different serotypes show different pathogenicity when tested in various hosts. The general and biochemical properties of the various strains are very similar, and from this point of view these organisms all belong to the single species P. multocida . The organisms can be divided into two pathogenic groups: those causing a hemorrhagic septicemia and those causing non-hemorrhagic septicemia. Pasteurella multocida and P. haemolytica show several biochemical properties in common but they differ with respect to indole production and hemolysis, and there is no antigenic relationship between the two species. This chapter summarizes the history of the nomenclature of P. multocida . Burril was the first to describe the organism as Micrococcus gallicidus that had been isolated from the blood of the domestic fowl suffering from “chicken cholera.”

Inhibition of Viral Multiplication in Acute and Chronic Stages of Infection by Ribozymes Targeted against the Polymerase Gene of Mouse Hepatitis Virus

Two hammerhead ribozymes targeted against the polymerase gene of mouse hepatitis virus (MHV), which consisted of 22-nucleotide (nt) ribozyme core sequences and antisense sequences of different lengths, 243-nt (S-ribozyme) and 926-nt (L-ribozyme), were tested for their++ inhibitory effects on viral multiplication. Vectors that expressed the ribozymes were transfected into mouse DBT cells and several resulting cell lines constitutively expressing the ribozymes were selected and examined for intracellular MHV multiplication in acute and chronic stages of infection. The production of infectious progeny viral particles was significantly reduced in the transfected cell lines expressing either the S-ribozyme or L-ribozyme in acute infection. Although the in vitro cleavage process of the L-ribozyme was slower than that of the S-ribozyme, no difference was observed in inhibitory effects on MHV multiplication between S- and L-ribozymes in the transfected cells. In the transfected cells expressing L-ribozymes, production of viral particles was also inhibited in the chronic stage of MHV infection.

Nucleosomal structure of Marek's disease virus genome in transformed lymphoblastoid cell lines, MDCC-MSB1 and MDCC-RP1.

The latent MDV (Mareks disease virus) genomes are folded into nucleosomal structures in both virus‐productive and ‐nonproductive lymphoblastoid cell lines, MDCC‐MSB1 (MSB‐1) and ‐RP1 (RP‐1), respectively. There was no difference between transcriptionally active and inactive regions of MDV genome with regard to nucleosomal patterns. In order to investigate whether nucleosomal structure is correlated with the repression of the transcription of MDV genome in lymphoblastoid cells, we examined the DNasel sensitivity of nucleosomal MDV DNA in lymphoblastoid cell lines, MSB‐1 and RP‐1. No difference in the DNasel sensitivity between transcriptionally active and inactive MDV DNA regions in lymphoblastoid cells was observed.

A Serological Study of Veillonella alcalescens Isolated from Ruminants

Serological grouping of Veillonella alcalescens strains isolated from the alimentary tract was performed by cross agglutination. There were complicated antigenic relationships among these strains, which were divided basically into two groups. One group consisted of strains of rumen origin and the other of strains of lower alimentary tract origin.When Veillonella alcalescens was examined for antigenic structure, it possessed heat-labile antigen in addition to somatic antigen. Furthermore, it was clarified that formolized antigen was closely related to heat-labile antigen. This heat-labile antigen corresponded to K-antigen of enterobacteria. It resembled C-type antigen found in Proteus, but did not resemble B-type antigen of Neisseria gonorrhoeae.

Population levels of Lactobacillus and Escherichia coli in the intestine of gnotobiotic pigs

無菌豚に乳酸菌を先行定着させ,遅れて大腸菌を投与した場合,両者の菌数が腸管内でどのように変化するかをしらべたところ,つぎのような成績が得られた。1. 7日令の無菌豚に豚糞便由来の乳酸菌を径口投与したところ,糞便中への該菌の出現は,24時間後では認められなかつたが,48時間後には糞便1g中109個程度が検出されるようになり,以後この菌数は安定して持続した。2. 投与乳酸菌が,糞便中109個程度に先行定着した5日後に,豚に病原性のない大腸菌を追加径口投与したところ,該菌の増殖が乳酸菌で抑制されることなく,すでに24時間後の糞便中には一挙に1010個程度検出され,大腸菌優位の糞便菌叢が成立した。この菌叢は,48時間後でも変わらなかつた。3. 乳酸菌および大腸菌がそれぞれ定着した消化管各部での両菌の均衡は,上部消化管では乳酸菌が,また下部消化管では大腸菌がそれぞれ優位であつた。4. これらの豚は,臨床上健康状態を保持し,下痢などの発生もみられなつた。