Analysis of the sequence of a new cryptic plasmid, pRJF2, from a rumen bacterium of the genus Butyrivibrio: Comparison with other Butyrivibrio plasmids and application in the development of a cloning vector

Abstract A small cryptic plasmid, pRJF2, from Butyrivibrio fibrisolvens strain OB157 was isolated and sequenced. The plasmid is similar in organisation to the previously sequenced Butyrivibrio plasmid, pRJF1, with two open reading frames, ORF1 and ORF2, flanking a region tentatively identified as the replication origin, and a region of unknown function defined by terminal 79 bp invert repeats. The sequences of ORF1, ORF2, and the presumptive replication origin are highly conserved. The sequence between the 79 bp invert repeats is not, and is therefore presumed to be of lesser functional significance, although the 5' and 3' termini are still highly conserved. The functional importance for plasmid replication of these regions was tested by constructing potential shuttle vectors, each lacking one or more of the regions of interest. When the region between the invert repeats was deleted and replaced by the erythromycin resistance gene from pAM β1 together with pUC18, to produce the 7.9 kb chimaeric plasmid pYK4, the construct was successfully transformed into E. coli and B. fibrisolvens by electroporation, and was stably maintained in both hosts. Both ORF1 and ORF2 were required for successful transformation of B. fibrisolvens .     

Histochemical and immunohistochemical studies on the articular disk of the temporomandibular joint in rats

The effects of surgically induced malocclusion upon the articular disk of the temporomandibular joint in adult male rats were investigated histochemically and immunohistochemically using antibody against type II collagen. In the intermediate portion of the articular disk, the number of collagen fibers and chondrocytes was much less and the collagen fibers became more wavy, rough and irregular in surgically operated rats than in control rats. Clusters of chondrocytes were found in some experimental rats. The present experiments revealed that surgically induced malocclusion causes noticeable changes in collagen fibers and chondrocytes within the extracellular matrix of the articular disk of the temporomandibular joint.     

Comprehensive DNA microarray expression profiles of tumors in tenascin-C-knockout mice

Tenascin-C (TNC), an extracellular matrix glycoprotein, plays a pivotal role in tumor growth. However, the mechanism whereby TNC affects tumor biology remains unclear. To investigate the exact role of TNC in primary tumor growth, a mouse mammary tumor cell line, GLMT1, was first developed. Subsequently, global gene expression in GLMT1-derived tumors was compared between wild-type (WT) and TNC-knockout (TNKO) mice. Tumors in WT mice were significantly larger than those in TNKO mice. DNA microarray analysis revealed 447 up and 667 downregulated in the tumors inoculated into TNKO mice as compared to tumors in WT mice. Validation by quantitative gene expression analysis showed that Tnc, Cxcl1, Cxcl2, and Cxcr2 were significantly upregulated in WT mice. We hypothesize that TNC stimulates the CXCL1/2-CXCR2 pathway involved in cancer cell proliferation.     

The Gene Encoding Flavanone 3-Hydroxylase is Expressed Normally in the Pale Yellow Flowers of the Japanese Morning Glory Carrying the speckled Mutation Which Produce Neither Flavonol nor Anthocyanin but Accumulate Chalcone, Aurone and Flavanone

The Japanese morning glory carrying the recessive mutable speckledallele with the dominant speckled-activator bears colorlessflowers with fine and round colored spots distributed over thecorolla whereas the plant without the speckled-activator producespale yellow flowers. Previous chemical analysis has indicatedthat a mutation in the gene for flavanone 3-hydroxylase (F3H)is a likely candidate for the speckled allele. However, theF3HmRNA without sequence alteration accumulates normally inthe pale yellow flowers, indicating that the speckled alleleis neither the F3H gene nor a regulatory gene acting on theF3H gene expression. (Received April 4, 1997; Accepted June 2, 1997)     

Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.     

Effect of dibutyryl cAMP on cell cycle progression of rat brain tumor cells in vitro

Summary Autoradiographic and flow microfluorometry analyses have been applied to a study of perturbed cell kinetics in 9L rat brain tumor cells treated with dibutyryl cyclic AMP and theophylline alone and in combination in vitro. At a concentration of 1 mM each, cell growth ceased shortly after the administration of these drugs. The results indicate that cells in S and G₂ phase at the time of drug administration can undergo mitosis even though a considerable prolongation of G₂ phase was apparent. However, cells in G₁ at the time of drug administration were arrested in that phase whereas those cells in S or G₂ were able to complete one mitosis before becoming arrested in the G₁ phase. This blocking effect was reversible, and cells resumed proliferation at a normal rate shortly after the removal of these drugs. This work was supported in part by NIH Cancer Research Center Grant CA-13525 and CA-19992 from NCI, and by the Association for Brain Tumor Research. Presented at the 6th International Cell Cycle Conference, March, 1976, New Orleans, Louisiana. The tumor used in this study was provided by William H. Sweet, Paul T. Kornblith, Janette L. Messer and Beverly O. Whitman of the Massachusetts General Hospital, Boston, Massachusetts.     

Genetic differentiation ofOryzias minutillus in Thailand

An allozyme survey was conducted in eleven local populations ofOryzias minutillus from Thailand. The region-specific distribution of alleles and the genetic relationship among the eleven populations revealed that they represented major three population groups, within the country as a whole; the Peninsular, Mae Nam Chao Phraya and Mekong subpopulations. Because their distribution boundaries coincide with geographic features, it is supposed that their genetic differentiation is primarily due to geographic isolation. Karyotype polymorphism has been reported only from the Mae Nam Chao Phraya subpopulation, suggesting that the variant karyotype evolved after allopatric isolation of the three subpopulations.