Segmented gene conversion as a mechanism of correction of 18S rRNA pseudogene located outside of rDNA cluster in D. melanogaster

INTRODUCTION: Acute scrotum in the pediatric age is mainly related to surgical causes. Spermatic cord torsion and inguinoscrotal hernia must be ruled out first, because of the possible ischemic damage to gonadal tissue and therefore surgery is sometimes performed directly, thus representing also a diagnostic tool. Spermatic cord torsion is found in two age ranges, namely: the neonatal period, where it usually represents the evolution of an intrauterine process, and the peripubertal period, which is more frequent. An unquestionable and prompt diagnosis is particularly needed because of the extreme sensitivity of gonadal tissue to ischemia. In this particular field, color and power Doppler US, depicting gonadal flow, have greatly increased diagnostic imaging capabilities, which were previously limited to B-mode US. MATERIAL AND METHODS: We examined 19 peripubertal patients with the diagnosis of spermatic cord torsion made on the basis of B-mode US and then confirmed with color Doppler. RESULTS: We found two signs which can be considered highly suggestive of spermatic cord torsion: the spiral twist of spermatic vessels and the peculiar extent of reactive hydrocele, caused by the bell clapper anomaly of the vaginal sac. CONCLUSIONS: The above US patterns are very helpful to diagnose spermatic cord torsion.     

Phylogenetic relationships of artiodactyls and cetaceans as deduced from the comparison of cytochrome b and 12S rRNA mitochondrial sequences

Functional neuroimaging studies in schizophrenia have often been confounded by various factors including medication status. To explore the effects of antipsychotic medications on relative regional cerebral perfusion, we scanned a group of 33 persons with schizophrenia twice, while receiving a stable dose of antipsychotic and after being off antipsychotics for 3 weeks, using technetium-99m hexamethyl-propyleneamine oxime single photon emission computed tomography (Tc-99m HMPAO-SPECT. We found that antipsychotic significantly increased the mean relative cerebral perfusion in the left basal ganglia. Additionally, patients receiving thiothixene (n = 9) had a significantly greater increase in relative cerebral perfusion in the basal ganglia than patients receiving haloperidol (n = 12). These findings indicate that antipsychotics lead to regional increases in cerebral perfusion and that antipsychotic status must be controlled for in functional neuroimaging studies. Functional neuroimaging techniques such as SPECT may be useful in furthering our understanding of the mechanism of antipsychotics.     

Molecular phylogeny of extant gymnosperms and seed plant evolution: analysis of nuclear 18S rRNA sequences

To study the evolutionary relationships among the four living gymnosperm orders and the interfamilial relationships in each order, a set of 65 nuclear 18S rRNA sequences from ferns, gymnosperms, and angiosperms was analyzed using the neighbor-joining and maximum-parsimony methods. With Selaginella as the outgroup, the analysis strongly indicates that the seed plants form a monophyletic group with the ferns as a sister group. Within the seed plants the angiosperms are clearly a monophyletic group. Although the bootstrap support for the monophyly of the gymnosperm clade is moderate, the monophyly is further supported by its lack of angiosperm-specific indels. Within the gymnosperms there appear to be three monophyletic clades: Cycadales-Ginkgoales, Gnetales, and Coniferales. The cycad-ginkgo clade is the earliest gymnosperm lineage. Given the strong support for the sister group relationship between Gnetales and Coniferales, it is unlikely that Gnetales is a sister group of the angiosperms, contrary to the view of many plant taxonomists. Within Coniferales, Pinaceae is monophyletic and basal to the remaining conifer families, among which there are three monophyletic clades: Phyllocladaceae-Podocarpaceae, Araucariaceae, and Sciadopityaceae-Taxaceae-Cephalotaxaceae-Taxodiacea e-Cupressaceae. Within the latter clade, Sciadopityaceae may be an outgroup to the other four families. Among the angiosperms, no significant cluster at the level of subclass was found, but there was evidence that Nymphaeaceae branched off first. Within the remaining angiosperms, the monocots included in this study are nested and form a monophyletic group. This study attests to the utility of nuclear 18S rRNA sequences in addressing relationships among living gymnosperms. Considerable variation in substitution rates was observed among the ferns and seed plants.     

Phylogenetic position of the Phacotaceae within the Chlamydophyceaeas revealed by analysis of 18S rDNA and rbcL sequences

A group of 32 healthy adult volunteers completed three blocks of a reaction time task that varied in the degree of controlled processing load. A rest period preceded each of the task blocks. The task blocks were presented in the order of either increasing or decreasing cognitive load. For each of the six periods, mean values and spectral measures of heart rate and respiration variability were calculated. The spectral measures were obtained for three different frequency bands. Differences between the cardiac measures of the task and preceding rest periods were compared with respect to differences in task load and the order of task presentation. All comparisons were carried out while adjusting for respiratory variability in the corresponding frequency band. The frequency band in which task load-related changes in heart rate variability became manifest appeared to be dependent on the individual's breathing pattern.     

Evolution and systematics of Anopheles: insights from a molecular phylogeny of Australasian mosquitoes

Relationships among the genus Anopheles and its many sibling species-groups are obscure despite the importance of anophelines as the vectors of human malaria. For the first time, the interrelationships and the origin of Australasian members of the subgenus Cellia are investigated by a cladistic analysis of sequence variation within the mitochondrial cytochrome oxidase subunit II gene. Estimated divergence times between many Australasian and Oriental taxa predate the mid Miocene collision of Australasia and Southeast Asia. Phylogenetic analysis suggests that two-way exchanges with Oriental mosquitoes rather than only immigration may have been a characteristic of anopheline paleobiogeography in Australasia. The Australasian fauna is mostly included in a large clade. The medically important Punctulatus Group is monophyletic and appears derived from Oriental stock. Populations within this group from as far apart as Australia and Vanuatu were in contact in the recent past (i.e., 0.35-2.44 mya), supporting dispersal rather than vicariance explanations. Some support for the monophyly of the Myzomyia, Neomyzomyia, and Pyretophorus Series was found. However, the subgenera Anopheles and Cellia and the Neocellia Series are paraphyletic, but branch support at these taxonomic levels was poor. The COII gene shows promise for questions concerning alpha taxonomy but appears to be of limited use for resolving deeper relationships within the Anopheles.     

Higher-level snake phylogeny inferred from mitochondrial DNA sequences of 12S rRNA and 16S rRNA genes

N-Nitrosomethylbenzylamine (NMBA) is a potent esophagus-specific carcinogen that has been utilized extensively in the study of esophageal carcinogenesis in rats. While many studies have focused on the pathogenesis of NMBA-induced esophageal tumors, the tumorigenicity of NMBA itself has not been thoroughly investigated in any single, systematic dose-response study. Therefore, in this study we evaluated NMBA tumorigenicity in rats following various short-term s.c. treatment regimens with the aim of developing an abbreviated treatment protocol which could be used in future studies. To assess the possible correlation of basal cell proliferation with NMBA tumorigenicity, we evaluated the expression of proliferating cell nuclear antigen (PCNA) in both control and NMBA-treated rats. In rats which received a cumulative NMBA dosage of 7.5 mg/kg over the course of 5 weeks, tumor incidence and multiplicity were as follows: 40% with 0.4 +/- 0.3 tumors/rat at week 10; 100% with 2.2 +/- 1.0 tumors/rat at week 20; and 100% with 2.3 +/- 1.0 tumors/rat at week 30. These rats exhibited marked increases in basal cell labeling, with indices that were 1.5- to 1.8-fold higher than controls. NMBA treatment regimens of shorter duration with equivalent or higher cumulative dosages were generally ineffective in producing esophageal tumors, even though significantly elevated levels of basal cell proliferation occurred. Together, these findings indicate that the duration of NMBA treatment is of critical importance in the tumorigenic potential of the carcinogen.     

Phylogenetic analyses of Staphylococcus based on the 16S rDNA sequence and assignment of clinical isolates from animals

Investigation of silver-stained nucleoli has been made in mono- and binuclear rat hepatocytes of different ploidy. Morphometric parameters of nucleoli and cell ploidy (after silver removing and Feulgen staining) were measured by image analyzer "Videotest". It has been shown that the total area and total volume of nucleoli correlate with cell ploidy, but the found dependence deviates from the proportional one. Possible reasons of such a deviation have been discussed. Marked correlation of total area or total volume of nucleoli was detected between pairs of nuclei of binuclear hepatocytes, whereas between accidental pairs of mononuclear hepatocytes such correlation is practically lacking.     

Toward the phylogeny of the family Lacertidae: implications from mitochondrial DNA 12S and 16S gene sequences (Reptilia: Squamata)

A phylogeny of the family Lacertidae was derived from mtDNA gene sequence data. Seventeen species, representing 16 currently recognized genera and subgenera, were included in the analysis. A total of 954 bp was obtained and aligned from 12S and 16S partial gene sequences. A preferred tree was selected based on weighted parsimony and functional ingroup and outgroup analyses. Decay analysis, bootstrapping, and permutation tail probability were used to evaluate support for the recovered nodes. The genus Gallotia was resolved as the basal taxon and the sister group of all remaining lacertids. Takydromus branched off next. All African lacertids grouped together and formed a monophyletic clade with the Eurasian genera Eremias and Ophisops. The remaining Eurasian lacertids sequentially branched off near the base of the tree in a "comb-like" fashion. The basal position of Gallotia and the monophyly of African lacertids are consistent with previous hypotheses. The European-origin hypothesis of lacertids is favored, and the distribution of lacertids in Africa is likely a Miocene dispersal event. Most of the extant European lacertids probably arose after the Eocene. The classification of the family needs to be revised.     

Sequence analysis of 18S-28S rRNA spacer regions from Saccharomyces kunashirensis, S. martiniae, S. rosinii, and S. transvaalensis

Although bone response can be evaluated by radiography, there have been no reports in human confirming formation of new soft tissue in limb lengthening. This study evaluated the tensile force between pin clamps in 14 lower limb lengthenings. Legs were lengthened 0.5 mm every 12 hours and the tensile was measured continuously. The tensile force increased simultaneously with each lengthening and decreased gradually. However, the reduction rate of tensile force during the nighttime (120+/-22%) was significantly higher than that during the daytime (72+/-10%). This differed from the stress relaxation phenomenon shown by viscoelastic material and suggested the presence of other phenomena such as histogenesis.     

Solution conformation and dynamics of an extracellular polysaccharide isolated from Bradyrhyzobium as deduced from 1H-NMR off resonance ROESY and 13C-NMR relaxation measurements

The conformational and dynamical features of an extracellular branched deacetylated polysaccharide isolated from Bradyrhizobium (Chamaecytisus proliferus) have been investigated by homo and heteronuclear NMR methods. 1H-NMR cross relaxation rates have been obtained for this polysaccharide through regular NOESY and ROESY spectra as well as by modern off resonance ROESY techniques. Local proton-proton correlation times as well as interproton distances have been obtained. 13C-NMR relaxation parameters (T1, T2, NOE) have also been measured at two different magnetic fields and interpreted using different approximations based on the Lipari and Szabo model free approach. The analysis of the data indicates the existence of important flexibility for the different linkages of the polysaccharide. Motions in the range of several ns contribute to the relaxation of the macromolecule, although faster internal motions in the 600-800 ps time scales are also present. These time scales indicate that segmental motions as well as internal motions around the glycosidic linkages are the major sources of relaxation for this molecule at 299 K.     

Families and natural history of lipids in childhood: an 18-year follow-up study

The natural history of total cholesterol and lipoprotein cholesterol in offspring was studied in relation to total cholesterol levels in their parents in the Epidemiological Prevention Study of Zoetermeer (EPOZ). All residents of 5 or more years who were living in two districts in the Dutch town of Zoetermeer were invited to participate in a study on indicators for chronic diseases between 1975 and 1978. In a random sample of 483 youngsters who were 5-19 years old, yearly measurements of cardiovascular risk factors were performed during a follow-up period of 18 years (average follow-up, 13.8 years). Total and subfraction cholesterol levels in offspring during follow-up were studied by tertiles of age-adjusted total cholesterol in their parents. Total and low density lipoprotein (LDL) cholesterol levels measured from childhood into young adulthood differed significantly between offspring whose fathers were in the highest total cholesterol tertile compared with those whose fathers were in the lowest tertile, amounting to 0.4 mmol/liter for total cholesterol and 0.5 mmol/liter for LDL cholesterol. Offspring differences by maternal tertiles amounted to 0.5 mmol/liter for total cholesterol and 0.6 mmol/liter for LDL cholesterol. Offspring (n = 53) with both parents in the upper cholesterol tertile had almost 1 mmol/liter higher cholesterol levels compared with offspring (n = 51) with both parents in the lowest tertile, whereas offspring (n = 48) with both parents in the middle tertile had intermediate levels. Differences remained after adjustment for sex, Quetelet index, systolic and diastolic blood pressure, and use of alcohol, cigarettes, and oral contraceptives. Offspring group differences in total and LDL cholesterol were already present in childhood and persisted into young adulthood. There was no clear relation between offspring change in cholesterol levels and parental total cholesterol levels. For high density lipoprotein cholesterol and its subfractions, no relations with parental total cholesterol levels were found. Based on the evidence of a strong positive relation between total cholesterol levels in parents and offspring levels of total and LDL cholesterol measured from childhood into young adulthood, the authors conclude that total and LDL cholesterol levels in offspring may already be characterized from young age and beyond through cholesterol levels in their parents.     

Allele frequencies and molecular diagnosis in haemophilia A and B patients from Russia and from some Asian republics of the former U.S.S.R

Using the C.B.17 scid mouse strain, we have developed a model of disseminated leukaemia and myeloma using five human cell lines, CCRF-Cem, Molt-4, Raji, IM9 and HS-Sultan. Introduction of any of these cell lines by either an intravenous or an intraperitoneal route eventually kills the mouse due to leukaemia or myeloma cell load. Neoplastic cells can be found in the blood, liver and bone marrow. Intraperitoneal transfer produces a local solid tumour whereas intravenous transfer produces foci of neoplastic cells in the spine and brain. A single dose of melphalan is able to increase survival time from infection of a lethal dose of the T-cell leukaemia cell line, CCRF-Cem.     

Probing the structure of mouse Ehrlich ascites cell 5.8S, 18S and 28S ribosomal RNA in situ

The secondary structure of mouse Ehrlich ascites 18S, 5.8S and 28S ribosomal RNA in situ was investigated by chemical modification using dimethyl sulphate and 1-cyclohexyl-3-(morpholinoethyl) carbodiimide metho-p-toluene sulphonate. These reagents specifically modify unpaired bases in the RNA. The reactive bases were localized by primer extension followed by gel electrophoresis. The three rRNA species were equally accessible for modification i.e. approximately 10% of the nucleotides were reactive. The experimental data support the theoretical secondary structure models proposed for 18S and 5.8/28S rRNA as almost all modified bases were located in putative single-strand regions of the rRNAs or in helical regions that could be expected to undergo dynamic breathing. However, deviations from the suggested models were found in both 18S and 28S rRNA. In 18S rRNA some putative helices in the 5'-domain were extensively modified by the single-strand specific reagents as was one of the suggested helices in domain III of 28S rRNA. Of the four eukaryote specific expansion segments present in mouse Ehrlich ascites cell 28S rRNA, segments I and III were only partly available for modification while segments II and IV showed average to high modification.     

The RecA protein as a model molecule for molecular systematic studies of bacteria: comparison of trees of RecAs and 16S rRNAs from the same species

The evolution of the RecA protein was analyzed using molecular phylogenetic techniques. Phylogenetic trees of all currently available complete RecA proteins were inferred using multiple maximum parsimony and distance matrix methods. Comparison and analysis of the trees reveal that the inferred relationships among these proteins are highly robust. The RecA trees show consistent subdivisions corresponding to many of the major bacterial groups found in trees of other molecules including the alpha, beta, gamma, delta, epsilon proteobacteria, cyanobacteria, high-GC gram-positives, and the Deinococcus-Thermus group. However, there are interesting differences between the RecA trees and these other trees. For example, in all the RecA trees the proteins from gram-positive species are not monophyletic. In addition, the RecAs of the cyanobacteria consistently group with those of the high-GC gram-positives. To evaluate possible causes and implications of these and other differences phylogenetic trees were generated for small-subunit rRNA sequences from the same (or closely related) species as represented in the RecA analysis. The trees of the two molecules using these equivalent species-sets are highly congruent and have similar resolving power for close, medium, and deep branches in the history of bacteria. The implications of the particular similarities and differences between the trees are discussed. Some of the features that make RecA useful for molecular systematics and for studies of protein evolution are also discussed.     

Origin and diversification of hindwingless Damaster ground beetles within the Japanese islands as deduced from mitochondrial ND5 gene sequences (Coleoptera, Carabidae)

Genealogical trees have been constructed using mitochondrial ND5 gene sequences of 78 Damaster (s. str.) specimens from all over the Japanese Islands. Eight lineages (called races in this paper) have been recognized. The races are tightly linked to geography with sharp distribution boundaries between them. The races and their distribution ranges do not coincide with those of classical morphology. Based on the observed distribution of the mitochondrial DNA haplotypes and the geohistorical data, we propose a diversification scenario of Damaster.