Molecular Detection,Isolation, and Physiological Characterization of Functionally Dominant Phenol-Degrading Bacteria in Activated Sludge

DNA was isolated from phenol-digesting activated sludge, and partial fragments of the 16S ribosomal DNA (rDNA) and the gene encoding the largest subunit of multicomponent phenol hydroxylase (LmPH) were amplified by PCR. An analysis of the amplified fragments by temperature gradient gel electrophoresis (TGGE) demonstrated that two major 16S rDNA bands (bands R2 and R3) and two major LmPH gene bands (bands P2 and P3) appeared after the activated sludge became acclimated to phenol. The nucleotide sequences of these major bands were determined. In parallel, bacteria were isolated from the activated sludge by direct plating or by plating after enrichment either in batch cultures or in a chemostat culture. The bacteria isolated were classified into 27 distinct groups by a repetitive extragenic palindromic sequence PCR analysis. The partial nucleotide sequences of 16S rDNAs and LmPH genes of members of these 27 groups were then determined. A comparison of these nucleotide sequences with the sequences of the major TGGE bands indicated that the major bacterial populations, R2 and R3, possessed major LmPH genes P2 and P3, respectively. The dominant populations could be isolated either by direct plating or by chemostat culture enrichment but not by batch culture enrichment. One of the dominant strains (R3) which contained a novel type of LmPH (P3), was closely related to Valivorax paradoxus, and the result of a kinetic analysis of its phenol-oxygenating activity suggested that this strain was the principal phenol digester in the activated sludge.Many scientists have used the rRNA approach (29, 30) to detect microbial populations and to describe the structures of microbial communities in various environments without isolating the component microorganisms. These studies have shown that most 16S ribosomal DNA (rDNA) sequences directly amplified from environmental samples are different from the sequences of comparable laboratory strains. Workers have concluded from such observations that many bacteria that are predominant in the natural environment have not been isolated in the laboratory yet and that the microbial diversity in the natural environment is much greater than the diversity of the bacteria that have been isolated (2, 7, 13, 25, 35, 36, 39, 40).Currently, one important aspect of microbial ecology studies is functional dissection of microbial communities based on structural information obtained by the approach mentioned above. An analysis of a population shift accompanied by a change in the function of a community yields information useful for identifying functionally dominant populations (2, 3, 42), although information concerning the function (activity) of each population can never be obtained by this kind of approach. Hence, workers have emphasized that pure-culture experiments are indispensable for detailed analysis of the functions of each population and that isolation of the functionally dominant populations in a microbial community is quite important.Phenol and its derivatives are some of the major hazardous compounds in industrial wastewater (1, 31, 43), and for this reason biodegradation of phenol has attracted keen attention (34, 46). However, since most studies of phenol biodegradation have been carried out under laboratory conditions with arbitrarily selected phenol-degrading bacteria, phenol biodegradation in the environment is not well understood yet. In the present study, to better understand phenol degradation in activated sludge, we isolated and characterized the phenol-degrading bacteria that were identified by the rRNA approach to be the dominant population in phenol-digesting activated sludge. Physiological and genetic differences between the dominant phenol-degrading bacteria isolated in this study and representative phenol-degrading bacteria characterized previously in several laboratories are discussed below.     

Apoptosis in Feline Panleukopenia Virus-Infected Lymphocytes

Feline panleukopenia virus (FPLV) was shown to induce apoptosis to feline lymphoid cells and to reduce the expression of interleukin-2 receptor α on the cells. FPLV-induced apoptosis might be a key element in the pathophysiology of atrophy of lymphoid tissues associated with feline panleukopenia caused by FPLV.     

Fgr Expression Restricted to Subpopulation of Monocyte/Macrophage Lineage in Resting Conditions Is Induced in Various Hematopoietic Cells after Activation or Transformation

The c-fgr gene product (Fgr) is a member of the src-family of protein tyrosine kinases. We have established a monoclonal antibody (2H2) which recognizes the unique N-terminal domain of the murine Fgr. In the present study, using immunohistochemical analysis and immune complex kinase assay with the 2H2, we investigated expression of Fgr in various cell populations and tissues in a murine system. In resting conditions, Fgr expression was confined to subsets of a monocyte/macrophage lineage. Thus, Fgr⁺ cells were detected in paracortical areas and medullas of lymph nodes, but seen only in marginal zones of the spleen and the medulla of the thymus. No Fgr⁺ macrophage was detected in other tissues, Peyer's patches, brain, heart, lung, liver, pancreas, kidney and peritoneal cavity. However, immune complex kinase assay revealed that, upon stimulation, T and B cells as well as peritoneal macrophages expressed significant levels of Fgr molecules. Transformed cell lines of lymphoid origin, EL-4 and LK35.2, which are T and B lineage lymphomas, respectively, also expressed Fgr molecules. Thus, various cells of hematopoietic origin appeared to possess a potentiality to express Fgr following activation or transformation. The present findings may help elucidate the functional significance of Fgr in immunologically committed cells in either activated or non-activated conditions.     

Increase of Specific Activity, Electrophoretic Type-Transition and Gene Expression of Alkaline Phosphatase during Endodermal Differentiation of F9 Mouse Embryonal Carcinoma Cells

In F9 mouse embryonal carcinoma cells, the specific activity of alkaline phosphatase (ALPase) increases markedly during endodermal differentiation induced by retinoic acid (RA) treatment, but the specific 5'-nucleotidase activity of a similar ecto-phosphatase increases only temporally. Polyacrylamide disc gel electrophoresis showed that F9 cells express only type I ALPase, whereas RA-treated F9 cells express both type I and type II ALPases. Type II ALPase is a minor form on day 1 of RA treatment and becomes the major form on day 4. RA-treated F9 cells also expressed mRNAs for endoderm cell-specific molecules, such as α-fetoprotein, type IV collagen and laminin B1 chain, but their expression of M₂-type pyruvate kinase mRNA of an essential non-ectoenzyme remains constant throughout endodermal differentiation. Northern blot analyses showed that type I ALPase was encoded by a liver (L)/bone (B)/kidney (K)/placenta (P)-type mRNA. The expression of L/B/K/P-type ALPase mRNA was induced in RA-treated F9 cells, but its increase preceded that of ALPase specific activity. These results suggest that the expression of L/B/K-type ALPase is regulated at the translational and/or post-translational level. The differential inhibition of ALPases by L-phenylalanine/L-homoarginine and the thermal inactivation (56°C for 60 min) inferred that type II ALPase was also an L/B/K-type isozyme.     

Regulatory DNA sequence conserved in the course of BK virus evolution

Summary Within the genome of human polyomavirus BK (BKV), there exists a noncoding regulatory region toward the late region side of the origin of DNA replication. In most BKV strains isolated by viral culture, this regulatory region contains tandem repeats varying in size. Recently. however, several laboratories isolated new BKV strains (designated as archetypal strains) lacking such repeat sequences. To examine the genetic relationship between archetypal strains, a phylogenetic tree was constructed for seven BKV strains, including three archetypal strains, from DNA sequence data on the late genes, those for leader protein (agnoprotein), and those for structural proteins (VP1, VP2, and VP3). For three strains data previously reported were used, whereas for the others sequences were determined in this study. From total numbers of nucleotide substitutions in each pair of strains, a phylogenetic tree was constructed by the unweighted pair-group method. The phylogenetic tree obtained reveals that BKV strains containing the archetypal regulatory region do not constitute a cluster of closely related strains and that these strains, together with those carrying the major part of the archetypal regulatory region, are widespread in the BKV population. This finding suggests that the basic structure of the archetypal regulatory region has been conserved in the course of BKV evolution.     

The effect of heart and skeletal muscle troponin complexes and calmodulin on the Ca2+-dependent reactions of phosphorylase kinase isoenzymes

The dephosphorylated form of phosphorylase kinase was purified 700-fold from rabbit heart extract. The purified enzyme had a pH 6.8/pH 8.2 activity ratio of 0.04-0.08 and was completely dependent on Ca2+ with an apparent Ka value for Ca2+ of 2.59 microM at pH 6.8. At free Ca2+ concentrations between 0.057 microM and 400 microM, 1.5 microM rabbit heart troponin complex had no significant effect on the reaction. However, 1.5 microM rabbit skeletal muscle troponin complex stimulated the reaction 1.5-2-fold with a concomitant decrease in the Ka value for Ca2+ to 1.40 microM. No differences in the effects of these troponin complexes were observed when heart-type and skeletal muscle-type phosphorylase b isoenzymes from either rabbit or pig were used as substrate. Similar effects of heart and skeletal muscle troponin complexes were observed on the Ca2+-dependent reaction of the dephosphorylated form of phosphorylase kinase partially purified from rabbit skeletal muscle. A saturating concentration (1.36 microM) of bovine brain calmodulin stimulated 2-5-fold the Ca2+-dependent reaction of skeletal muscle phosphorylase kinase, but not the reaction of heart phosphorylase kinase. Heart troponin complex (12 microM) suppressed 80-100% the stimulatory effect of skeletal muscle troponin complex on the reactions of phosphorylase kinase isoenzymes, but had no significant effect on the stimulation by calmodulin of skeletal muscle phosphorylase kinase reaction.     

Unveiling the origin of Quercus serrata subsp. mongolicoides found in Honshu,Japan, by using genetic and morphological analyses

Quercus mongolica is a tree found in temperate deciduous forests in east Asia. In Japan, Q. mongolica var. crispula is commonly found; moreover, an oak whose morphology is similar to that of Q. mongolica var. mongolica of the Asian continent has been found in certain areas of Honshu and Hokkaido. Recently, the oak found in Honshu was described as Q. serrata subsp. mongolicoides (QSM). However, genetic comparison between this oak and Q. mongolica var. mongolica of the Asian continent has not been performed; the origin of QSM is thus unknown. Therefore, we aimed to determine the origin of QSM by conducting nuclear microsatellite (nSSR), chloroplast DNA (cpDNA) and leaf morphology analyses for the three taxa, as well as other congeners. The cpDNA variation overlapped among the three taxa, suggesting low discrimination ability for these taxa. Although morphological congruency was found between QSM and Q. mongolica var. mongolica, results of nSSR analyses showed that QSM contained a genetic admixture of Q. mongolica var. mongolica of the Asian continent and Q. mongolica var. crispula of Japan, bolstering an admixture hypothesis. The nSSR and cpDNA analyses suggested that Q. mongolica var. crispula can be the progenitor of Q. mongolica var. mongolica and harbors the ancestral cpDNA haplotypes. Therefore, we concluded that QSM might have been created by an admixture that likely occurred within Japan between Q. mongolica var. crispula and putative relict Q. mongolica var. mongolica, which might have diverged in or around Japan from Q. mongolica var. crispula during the late Pleistocene.     

Transdifferentiation of putative neuronal cells of neural retina into lens: A demonstration by chick-quail chimeric cultures

Summary To elucidate the cell-type origin of lens cells, which differentiate in stationary cultures of neural retina, chimeric cultures between chick and quail cells were made to recombine xenoplastically the different cell fractions separated from 8- to 9-day cultures of 3.5-day-old embryonic neural retinal cells by means of centrifugation in Percoll. Extensive lentoidogenesis occurred in the recombination of the N2-fraction (consisting mostly of small round cells) with the E-fraction (containing a number of flattened epithelial cells). Taking advantage of the difference in electrophoretic mobility of chick and quail -crystallin, it was shown that this lens-specific protein, synthesized in the chimeric cultures, was mostly of the species-specificity of N2. Microscopic observations of histological sections of cell sheets of quail N2- and chick E-fraction chimeric cultures revealed that most cells with -crystallin, as identified by means of immunohistological detection, are provided with a nuclear marker characteristic of quail. By determining the level of activity of choline acetyltransferase and by examining the stainability with a fluorescent dye (Merocyanine-540), it was suggested that cells in the N2-fraction are primitive neuroblast-like cells. Thus, we can conclude that putative neuronal cells in early cultures of avian embryonic neural retina can transdifferentiate into lens cells.     

Identification of a binding region on Escherichia coli heat-stable enterotoxin to intestinal guanylyl cyclase C

Summary The heat-stable enterotoxin (ST), produced byEscherichia coli, causes acute diarrhea in infants and domestic animals by activation of the intestinal membrane-bound receptor, guanylyl cyclase C. We have investigated a region on the ST molecule, which is recognized by the receptor, by introducing a photochromophore,p-azidophenylalanine (Pap), into three different regions of STp(4–17), which has the full toxic activity. Each ST analog bound to the receptor, but only STp(4–17) containing a Pap residue at position 11 in the central portion of the ST molecule, showed a high efficiency in the reaction which cross-linked with the receptor by UV radiation. These data clearly demonstrate that the region of the ST molecule encompassing the Asn¹¹ residue directly interacts with the receptor.     

Anatomic and chromosomal anomalies in 944 induced abortuses

Summary A total of 944 induced abortuses, 922 of which apparently were anatomically normal and 22 of which were anatomically abnormal, were set up in culture. Of these abortuses, 910 (96.4%) were successfully karyotyped. The study can be divided into two periods. In the initial period, specimens without recovered fetal tissues were excluded, and no chromosome anomalies were found among the 182 abortuses karyotyped. In the later period of sutdy, abortion specimens both with and without recovered fetal tissues were included, and 23 chromosomally abnormal abortuses, 9 of which were without recovered fetal tissues, were found among the 728 abortuses karyotyped. This gives a chromosome abnormality rate of 3.2%. The mean ovulation age for the 728 abortuses was 63.4 days (range 33–109 days). The mean maternal age was 28.4 years (range 15–48 years). The chromosomally abnormal abortuses included 13 (10 nonmosaic and 3 mosaic) trisomics, 7 triploids, 2 abortuses with balanced D/D translocations and an abortus with an XXq- karyotype. Among the 616 abortuses in which both amniotic and fetal tissues were karyotyped, there was complete karyotypic agreement between the two tissues. Among the 339 abortuses in which tissue samples from both sides of the body were analyzed, complete agreement was also found. Factors that may influence the prevalence of abnormal karyotypes in induced abortuses are discussed.