The 16S-23S rRNA intergenic spacer region of Bartonella (Rochalimaea) species is longer than usually described in other bacteria

The isozymes of prostaglandin G/H synthase (PGHS) are shown to be differentially inhibited in vitro by currently marketed nonsteroidal anti-inflammatory drugs (NSAIDs) using microsomal rhPGHS-1 and rhPGHS-2. Comparison of selectivity ratios (IC50 rhPGHS-1/IC50 rhPGHS-2) demonstrated a 10-fold selectivity of etodolac (Lodine) for rhPGHS-2, whereas the other NSAIDs evaluated demonstrated no preference or a slight preference for inhibition of rhPGHS-1. In vitro enzyme results were supported by a human whole blood assay where etodolac also demonstrated a 10-fold selectivity for inhibition of PGHS-2 mediated TxB2 production. Taken together, these data may be key to explaining the clinically observed gastrointestinal safety of etodolac versus other marketed NSAIDs.     

Simultaneous detection and genotyping of three genomic groups of Borrelia burgdorferi sensu lato in Dutch Ixodes ricinus ticks by characterization of the amplified intergenic spacer region between 5S and 23S rRNA genes

We developed a rapid and reliable method for the identification Borrelia burgdorferi sensu lato species in ticks. We used the DNA sequence polymorphism of the spacer region between 5S and 23S rRNA genes, which has been shown to be able to discriminate between eight genomic groups of B. burgdorferi sensu lato (D. Postic, M. Assous, P. A. D. Grimont, and G. Baranton, Int. J. Syst. Bacteriol. 44:743-752, 1994). Spacer DNA was amplified by PCR and was then hybridized to five membrane-bound oligonucleotides. The oligonucleotides were specific for B. burgdorferi sensu stricto, Borrelia garinii, Borrelia afzelii, and group VS116. A probe which reacted with all genomic groups of B. burgdorferi sensu lato was also used. Ninety-six ticks collected in the field were destructed by bead beating, and the supernatant was used directly in a PCR. B. burgdorferi sensu lato DNA was detected in 6 of 57 adult ticks (11%) and 9 of 39 nymphs (23%). B. garinii was found in three nymphs and four adults, three nymphs carried B. afzelii, and one adult and one nymph carried group VS116. Double infections with B. afzelii and group VS116 were found in two nymphs and one adult. Thus, our method can simultaneously identify three genomic groups of B. burgdorferi sensu lato in ticks collected in the field. This technique provides new ways to study the association of genomic groups present in ticks and the risk of Lyme borreliosis.     

The Trypanosoma cruzi ribosomal RNA-encoding gene: analysis of promoter and upstream intergenic spacer sequences

The present study was designed to investigate the influence of endothelium-derived nitric oxide on the contractile responses of isolated human omental arteries to electrical field stimulation and noradrenaline. We measured isometric tension in artery rings obtained from portions of human omentum during the course of abdominal operations (32 patients). Electrical field stimulation induced frequency-dependent contractions which were abolished by tetrodotoxin (10(-6) M) and prazosin (10(-6) M), thus indicating that this effect was due to noradrenaline released from adrenergic nerves acting on alpha 1-adrenoceptors. The increases in tension induced by electrical field stimulation were of greater magnitude in arteries denuded of endothelium. NG-Nitro-L-arginine (L-NAME, 10(-4) M) potentiated the contractile response to electrical field stimulation in artery rings with endothelium but did not influence the contractile responses of endothelium-denuded arteries. The potentiation induced by L-NAME was completely reversed by L-arginine (10(-4) M), but not by D-arginine (10(-4) M). Contractile responses to noradrenaline were similar in arteries with and without endothelium. L-NAME (10(-4) M) had no significant effect on the contractile responses to noradrenaline. Our results suggest that electrical field stimulation releases endothelium-derived nitric oxide which inhibits the contractile responses of human omental arteries. The constrictor responses to noradrenaline are not modulated by the endothelium.     

Amplicons of maize zein genes are conserved within genic but expanded and constricted in intergenic regions

The properties are discussed of system y+L, a broad scope amino acid transporter which was first identified in human erythrocytes. System y+L exhibits two distinctive properties: (a) it can bind and translocate cationic and neutral amino acids, and (b) its specificity varies depending on the ionic composition of the medium. In Na+ medium, the half-saturation constant for L-lysine influx was 9.5 +/- 0.67 microM and the inhibition constant (Ki) for L-leucine was 10.7 +/- 0.72 microM. L-Leucine is the neutral amino acid that binds more powerfully, whereas smaller analogues, such as L-alanine and L-serine interact less strongly (the corresponding inhibition constants were Ki,Ala, 0.62 +/- 0.11 mM; Ki,Ser, 0.49 +/- 0.08 mM). In the presence of K+, the carrier functions as a cationic amino acid specific carrier, but Li+ is able to substitute for Na+ facilitating neutral amino acid binding. The effect of the inorganic cations is restricted to the recognition of neutral amino acids; translocation occurs at similar rates in the presence of Na+, K+ and Li+. The only structural feature that appears to impair translocation is bulkiness and substrates with half-saturation constants differing by more than 100-fold translocate at the same rate. This suggests that translocation is largely independent of the forces of interaction between the substrate and the carrier site. System y+L activity has been observed in Xenopus laevis oocytes injected with the cRNA for the heavy chain of the 4F2 human surface antigen. 4F2hc is an integral membrane protein with a single putative membrane-spanning domain and it remains to be clarified whether it is part of the transporter or an activator protein.     

Fine structure and evolution of the rDNA intergenic spacer in rice and other cereals

Pyridine has been shown to be an effective inducer of the ethanol-inducible cytochrome P-450IIE1 in both liver and lung. The oxidation of 2-butanol by rat liver is inducible by chronic ethanol consumption. The purpose of this study was to determine the effect of pyridine on the hepatic and pulmonary metabolism of butanol. Comparisons were made between rat and rabbit. Acute pyridine treatment (200 mg/kg, ip) increased hepatic metabolism of 2-butanol in the rat twofold and in the rabbit threefold. The effect of pyridine on hepatic butanol oxidase is similar to the effect reported by other investigators for ethanol administered in the drinking water for 3 wk. Control rabbit pulmonary butanol oxidase activity was 10-fold higher than that in the rat. Pyridine decreased pulmonary butanol oxidase activity in the rabbit. The effect was demonstrated both in vitro and in the isolated perfused rabbit lung. Pyridine had no effect on pulmonary butanol oxidase activity in the rat.     

An evaluation of intergenic rRNA gene sequence length polymorphism analysis for the identification of Legionella species

There are currently more than 40 species of Legionella and the identification of most of these by standard methods is technically difficult. The aim of this study was to assess the suitability of a previously published PCR-based method of identifying Legionella spp. Intergenic 16S-23S rDNA spacer regions were amplified with primers complementary to conserved regions of the rRNA genes. Following electrophoretic separation of the products, data analyses were performed with the Taxotron software package. Computer-assisted analysis (with an empirically derived error tolerance of 3%) could differentiate only 26 of the 43 strains (representing 43 species), with the remaining 17 species clustering into four groups (group I, comprising 10 species; group II, three species; group III, two species and group IV, two species). Analysis of well-characterised 'non-type' strains of some Legionella spp. (e.g., from type culture collections) resulted in patterns distinct from the corresponding type strain in most cases. Furthermore, recent isolates (identified by conventional methods) were identified by this PCR method to the presumed correct species (or species group) in only a minority of cases. Well characterised strains and recent isolates of Legionella showed heterogeneity within many species. This intra-species variation severely limits the usefulness of the method for the identification of isolates. However, this property may be useful for epidemiological typing within such species.     

Ribosomal DNA evolution at the population level: nucleotide variation in intergenic spacer arrays of Daphnia pulex

Nucleotide variation was surveyed in 21 subrepeat arrays from the ribosomal DNA intergenic spacer of three Daphnia pulex populations. Eighteen of these arrays contained four subrepeats. Contrary to expectations, each of the four positions within the array had a different consensus sequence. However, gene conversion, involving sequences less than the length of a subrepeat, had occurred between subrepeats in different positions. Three arrays had more than four subrepeats and were undoubtedly generated by unequal crossing over between standard-length arrays. The data strongly suggested that most unequal exchanges between arrays are intrachromosomal and that they occur much less frequently than unequal exchanges at the level of the entire rDNA repeat. Strong associations among variants at different positions allowed the recognition of five groups of arrays, two of which were found in more than one population. Five of the seven individuals surveyed had arrays from more than one group. Analysis of the distribution of nucleotide variation suggested that the populations were quite divergent, a result that is concordant with previous surveys of allozyme and mitochondrial DNA variation. It was suggested that some of the subrepeat array types are quite old, at least predating the recolonization of pond habitats in the midwestern United States after the last glaciation.     

Tomato Prf is a member of the leucine-rich repeat class of plant disease resistance genes and lies embedded within the Pto kinase gene cluster

In tomato, resistance to Pseudomonas syringae pv. tomato (Pst) strains expressing the avirulence gene avrPto requires the presence of at least two host genes, designated Pto and Prf. Here we report that Prf encodes a protein with leucine-zipper, nucleotide-binding, and leucine-rich repeat motifs, as are found in a number of resistance gene products from other plants. prf mutant alleles (4) were found to carry alterations within the Prf coding sequence. A genomic fragment containing Prf complemented a prf mutant tomato line both for resistance to Pst strains expressing avrPto and for sensitivity to the insecticide Fenthion. Prf resides in the middle of the Pto gene cluster, 24 kb from the Pto gene and 500 bp from the Fen gene.     

The CAG repeat within the androgen receptor gene and benign prostatic hyperplasia

Thalidomide, a glutamic acid derivative, has recently been shown to inhibit in vitro angiogenesis, the process of formation of new blood vessels. This Phase II study examined the pharmacokinetics of thalidomide in patients with clinically progressive hormone-refractory prostate cancer. Patients (aged 55 to 80 years) were randomized to two different arms, low dose versus high dose. Patients in the low-dose group were given 200 mg of thalidomide and patients in the high-dose group received 200 mg of thalidomide, with subsequent dose escalations to 1200 mg. Serial serum or blood samples were obtained for pharmacokinetic assessment after administration of a single oral dose or multiple daily dosing of thalidomide and were assayed by reversed-phase HPLC. Pharmacokinetic parameters for both the single and multiple dosing were calculated with ADAPT II. A one-compartment model best fit the data. After single dosing, the oral clearance and apparent volume of distribution for the low-dose regimen (n = 13) were 7.41 +/- 2.05 L/h and 66.93 +/- 34.27 L, respectively, whereas for the high-dose regimen (n = 11), these values were 7.21 +/- 2.89 L/h and 165.81 +/- 84.18 L, respectively. The elimination half-lives for the low and high dose were 6.52 +/- 3.81 and 18.25 +/- 14.08 h, respectively. After the multiple dosing of thalidomide, the oral clearance and apparent volume of distribution for the low-dose group (n = 10) were 6.35 +/- 1.64 L/h and 64.63 +/- 23.20 L, respectively, whereas for the high-dose group (n = 11), these values were 7.73 +/- 2.27 L/h and 167.85 +/- 82.08 L, respectively. The elimination half-lives for the low and high dose were 7.08 +/- 1.87 and 16.19 +/- 9.57 h, respectively. For both the single and multiple dosing of thalidomide, the apparent volume of distribution and half-life were significantly higher for the high-dose group than those for the low-dose group. The higher apparent volume of distribution may be attributable to several factors, such as change in absorption, protein binding, etc. A dose-proportional increase in thalidomide steady-state concentrations was seen after multiple daily dosing of thalidomide.     

Extralenticular expression of Xenopus laevis alpha-, beta-, and gamma-crystallin genes

PURPOSE: Extralenticular expression of alpha- and beta-crystallin genes has been demonstrated in mammals and expression of gamma-crystallin genes has been shown in Xenopus laevis. To determine a possible correlation between lens determination and crystallin gene expression, the site of expression of (a member of) the alpha-, beta-, and gamma-crystallin gene families was observed before and during lens formation in X. laevis. METHODS: The partial complementary DNAs (cDNAs) of alpha A- and beta A4-crystallin and a gamma-crystallin were cloned from an X. laevis lens cDNA library. The corresponding antisense RNAs were used to analyze the expression of these genes during X. laevis development by wholemount in situ hybridization. RESULTS: Expression of the beta A4- and gamma-crystallin (but not alpha-crystallin) genes could first be detected in the animal cap of the X. laevis gastrula. The beta A4- and gamma-crystallin messengers were also found in the first stage of lens development, when the ectodermal tissue overlying the optic vesicle thickens to form the lens placode. alpha A-crystallin messenger RNAs were only detectable when the lens epithelial cells were formed. CONCLUSIONS: In contrast to observations in most vertebrates, expression of the beta A4- and gamma-crystallin genes was observed to precede that of the alpha A-crystallin gene during lens development of X. laevis, reflecting the determination that in amphibians, the (presumptive) fiber cells are formed before the epithelial cells, whereas in vertebrates, the order is reversed. Expression of beta A4- and gamma-crystallin genes in the ectodermal tissue of the X. laevis gastrula shows that these genes are expressed when this tissue gains competence for lens formation.     

Structural features in the 3'' external transcribed spacer affecting intragenic processing of yeast rRNA

A total of 62 patients of gastric carcinoma were studied to find a correlation between newer prognostic indicators like cell proliferative indices including Nucleolar Organizer regions (AgNORs), Ki 67 Labelling Index and Epidermal Growth Factor Receptor (EGFR) expression with the various, histopathological criteria and compared with 30 controls of non neoplastic gastric diseases. EGFR expression was positive in 48(77.4%) cases. The Ki 67 labelling indices ranged from 0 to 50% with a mean of 21.35 +/- 17.88% among the cases. AgNOR counts ranged from 1.64 to 4.49 with a mean of 3.41 +/- 0.81 among the cases. Positive EGFR expression correlated strongly with differentiation of the tumour, poorly differentiated tumours showing a higher positivity. EGFR positivity also showed good correlation with metastasis as well as with the invasiveness of the tumour. Ki 67 labelling indices correlated significantly with metastatic status, microscopic types and degree of differentiation of the tumour. A strong correlation was observed between AgNOR counts and metastasis as well as the microscopic type of the tumour. EGFR expression correlated strongly with Ki 67 scores and weakly with AgNOR counts among the patients of gastric carcinoma.     

Update on Pneumocystis carinii f. sp. hominis typing based on nucleotide sequence variations in internal transcribed spacer regions of rRNA genes

Few data exist concerning expiratory muscle function in amyotrophic lateral sclerosis (ALS). We studied 26 patients with ALS (16 with respiratory symptoms and 10 without) and measured the maximal static expiratory mouth pressure (MEP), the gastric pressure during a maximal cough (Cough Pga), and the gastric pressure after magnetic stimulation of the lower thoracic nerve roots (Tw Pga). These measurements were related to the ability to generate transient supramaximal flow during a cough (cough spikes), to arterialized capillary blood gases, and to inspiratory muscle strength. Vocal cord motion was examined endoscopically in 11 of the 16 symptomatic patients. Expiratory muscle weakness was related to inability to generate cough spikes with a threshold effect such that spikes were absent for Cough Pga < 50 cm H2O (p = 0.009) or Tw Pga < 7 cm H2O (p = 0.006) and was usually associated with inspiratory muscle weakness. However, in multivariate analysis, PaCO2 was only significantly associated with the maximal sniff esophageal pressure (p = 0.02). Symptomatic patients had significantly lower inspiratory muscle strength, whereas, of the expiratory muscle tests, only Tw Pga was significantly lower (p = 0.0009) in symptomatic patients. Abnormal vocal cord motion was observed in two of the 11 patients examined. We conclude that abdominal muscle weakness in ALS, when substantial, results in an inability to generate transient supramaximal flow during a cough. However, the primary determinant of both ventilatory failure and respiratory symptoms seems to be inspiratory muscle weakness.     

Reiteration frequency of the histone genes in the genome of the amphibian, Xenopus laevis

Although female employment and fertility are generally inversely related in already developed countries, no clear association has been found in the developing economies. The absence of a uniform relationship is related to the problems of measurement for both variable s. Consequently, it is suggested that a better understanding of the relationship between fertility and employment for women can be obtained by giving consideration to: 1) the ecological or individual level of analysis, 2) the life cycle aspects of fertility and labor force participation by means of the use of small age groups in the analysis or cohort data if available, 3) the matching of current or historical perspective on both work and fertility, 4) more complete measures of fertility that consider both the number and spacing of children, and 5) a new approach to measuring the labor force and labor force participation as outlined in the Council of Asian Manpower Studies and the Organization of Demographic Associates approaches. Although there is a need for more data, the most important need is for different data and for different combinations of fertility and work data. It is particularly the labor force data that require a new approach. Both the gainful worker and labor force approaches were designed to measure the work of men in a Western society. These approaches were not designed nor can they be expected to provide useful service for measuring the very different work of women in developing countries, much less in relating work to other variables such as fertility. Thus, it is expected that the relationship between work and fertility will remain elusive under these circumstances. Neither the labor force dimension nor the other dimensions indicated have been generally considered in studies of work and fertility in developing countries. No study has been made using all these suggested dimensions. It is believed that the use of these dimensions is necessary in order to achieve a complete understanding of the relationship between female employment and fertility.     

Coding of hemolysins within the ribosomal RNA repeat on a plasmid in Entamoeba histolytica

The pathogenesis of amoebic dysentery is a result of cytolysis of the colonic mucosa by the parasitic protozoan Entamoeba histolytica. The cytolysis results in extensive local ulceration and allows the amoeba to penetrate and metastasize to distant sites. Factors involved in this process were defined with three clones that express hemolytic activities in Escherichia coli. These potential amoebic virulence determinants were also toxic to human colonic epithelial cells, the primary cellular targets in amoebal invasion of the large intestine. The coding sequences for the hemolysins were close to each other on a 2.6-kilobase segment of a 25-kilobase extrachromosomal DNA element. The structural genes for the hemolysins were within inverted repeats that encode ribosomal RNAs.     

Elaboration of the messenger transport organizer pathway for localization of RNA to the vegetal cortex of Xenopus oocytes

1. Two experiments were designed to study the influence of free fatty acid content and degree of saturation of free fatty acids and neutral fat on digestibility of added fats and fatty acids. Sunflower oil and tallow were used as neutral fats, and palmitic, stearic, oleic and linoleic acids as free fatty acids. Fat inclusion was 80 g/kg and mixtures of each fat and each free fatty acid were prepared in the proportions 100:0, 70:30 and 40:60. 2. Experimental diets were evaluated for fat and fatty acid digestibilities with broiler chickens at 21 d of age. The metabolisable energy of fat was calculated from the product of digestibility and gross energy. Increasing concentrations of saturated free fatty acids decreased the ME of added fat, whereas unsaturated free fatty acids did not significantly affect the ME value of added fat. 3. Digestibilities of individual fatty acids were analysed by linear regression with rate of inclusion of free fatty acid in the fat blend: palmitic and stearic acids gave a negative slope, whereas oleic and linoleic acids gave a slope not statistically different from zero. Because slopes for saturated fatty acids did not differ between the sunflower oil and tallow treatments, synergism between unsaturated and saturated fatty acids was not detected.