Ureaplasma parvum undergoes selection in utero resulting in genetically diverse isolates colonising the chorioamnion of fetal sheep

Ureaplasmas are the microorganisms most frequently isolated from the amniotic fluid of pregnant women and can cause chronic intrauterine infections. These tiny bacteria are thought to undergo rapid evolution and exhibit a hypermutatable phenotype; however, little is known about how ureaplasmas respond to selective pressures in utero. Using an ovine model of chronic intra-amniotic infection, we investigated if exposure of ureaplasmas to sub-inhibitory concentrations of erythromycin could induce phenotypic or genetic indicators of macrolide resistance. At 55 days gestation, 12 pregnant ewes received an intra-amniotic injection of a non-clonal, clinical U. parvum strain, followed by: (i) erythromycin treatment (IM, 30 mg/kg/day, n=6); or (ii) saline (IM, n=6) at 100 days gestation. Fetuses were then delivered surgically at 125 days gestation. Despite injecting the same inoculum into all ewes, significant differences between amniotic fluid and chorioamnion ureaplasmas were detected following chronic intra-amniotic infection. Numerous polymorphisms were observed in domain V of the 23S rRNA gene of ureaplasmas isolated from the chorioamnion (but not the amniotic fluid), resulting in a mosaic-like sequence. Chorioamnion isolates also harboured the macrolide resistance genes erm(B) and msr(D) and were associated with variable roxithromycin minimum inhibitory concentrations. Remarkably, this variability occurred independently of exposure of ureaplasmas to erythromycin, suggesting that low-level erythromycin exposure does not induce ureaplasmal macrolide resistance in utero. Rather, the significant differences observed between amniotic fluid and chorioamnion ureaplasmas suggest that different anatomical sites may select for ureaplasma sub-types within non-clonal, clinical strains. This may have implications for the treatment of intrauterine ureaplasma infections.

Characterization of 67 mitochondrial tRNA gene rearrangements in the Hymenoptera suggests that mitochondrial tRNA gene position is selectively neutral

We present entire sequences of two hymenopteran mitochondrial genomes and the major portion of three others. We combined these data with nine previously sequenced hymenopteran mitochondrial genomes. This allowed us to infer and analyze the evolution of the 67 mitochondrial gene rearrangements so far found in this order. All of these involve tRNA genes, whereas four also involve larger (protein-coding or ribosomal RNA) genes. We find that the vast majority of mitochondrial gene rearrangements are independently derived. A maximum of four of these rearrangements represent shared, derived organizations, whereas three are convergently derived. The remaining mitochondrial gene rearrangements represent new mitochondrial genome organizations. These data are consistent with the proposal that there are an enormous number of alternative mitochondrial genome organizations possible and that mitochondrial genome organization is, for the most part, selectively neutral. Nevertheless, some mitochondrial genes appear less mobile than others. Genes close to the noncoding region are generally more mobile but only marginally so. Some mitochondrial genes rearrange in a pattern consistent with the duplication/random loss model, but more mitochondrial genes move in a pattern inconsistent with this model. An increased rate of mitochondrial gene rearrangement is not tightly associated with the evolution of parasitism. Although parasitic lineages tend to have more mitochondrial gene rearrangements than nonparasitic lineages, there are exceptions (e.g., Orussus and Schlettererius). It is likely that only a small proportion of the total number of mitochondrial gene rearrangements that have occurred during the evolution of the Hymenoptera have been sampled in the present study.

Genetic evidence for natural hybridization between Red Snow Crab (Chionoecetes japonicus) and Snow Crab (Chionoecetes opilio) in Korea

Both red snow crab (Chionoecetes japonicus Rathbun, 1932) and snow crab (Chionoecetes opilio Fabricius, 1788) are commercially important species in Korea. The geographical ranges of the two species overlap in the East Sea, where both species are fished commercially. Morphological identification of the two species and putative hybrids can be difficult because of their overlapping morphological characteristics. The presence of putative hybrids can affect the total allowable catch (TAC) of C. japonicus and C. opilio, and causes problems managing C. japonicus and C. opilio wild resources. To date, however, no natural hybridization has been reported between C. japonicus and C. opilio, despite their overlapping distributions along the coast of the East Sea. In this study, the internal transcribed spacer (ITS) region of major ribosomal RNA genes from the nuclear genome and the cytochrome oxidase I (CO I) gene from the mitochondrial genome were sequenced to determine whether natural hybridization occurs between the two species. Our results revealed that all putative hybrids identified using morphological traits had two distinct types of ITS sequences corresponding to those of both parental species. Mitochondrial CO I gene sequencing showed that all putative hybrids had sequences identical to C. japonicus. A genotyping assay based on single nucleotide polymorphisms in the ITS1 region and the CO I gene produced the most efficient and accurate identification of all hybrid individuals. Molecular data clearly demonstrate that natural hybridization does occur between C. japonicus and C. opilio, but only with C. japonicus as the maternal parent.

Brief report: Intestinal dysbiosis in ankylosing spondylitis

Objective Ankylosing spondylitis (AS) is a common, highly heritable immune-mediated arthropathy that occurs in genetically susceptible individuals exposed to an unknown but likely ubiquitous environmental trigger. There is a close relationship between the gut and spondyloarthritis, as exemplified in patients with reactive arthritis, in whom a typically self-limiting arthropathy follows either a gastrointestinal or urogenital infection. Microbial involvement in AS has been suggested; however, no definitive link has been established. The aim of this study was to determine whether the gut in patients with AS carries a distinct microbial signature compared with that in the gut of healthy control subjects. Methods Microbial profiles for terminal ileum biopsy specimens obtained from patients with recent-onset tumor necrosis factor antagonist-naive AS and from healthy control subjects were generated using culture-independent 16S ribosomal RNA gene sequencing and analysis techniques. Results Our results showed that the terminal ileum microbial communities in patients with AS differ significantly (P < 0.001) from those in healthy control subjects, driven by a higher abundance of 5 families of bacteria (Lachnospiraceae [P = 0.001], Ruminococcaceae [P = 0.012], Rikenellaceae [P = 0.004], Porphyromonadaceae [P = 0.001], and Bacteroidaceae [P = 0.001]) and a decrease in the abundance of 2 families of bacteria (Veillonellaceae [P = 0.01] and Prevotellaceae [P = 0.004]). Conclusion We show evidence for a discrete microbial signature in the terminal ileum of patients with AS compared with healthy control subjects. The microbial composition was demonstrated to correlate with disease status, and greater differences were observed between disease groups than within disease groups. These results are consistent with the hypothesis that genes associated with AS act, at least in part, through effects on the gut microbiome.

Impact of rRNA methylations on ribosome recycling and fidelity of initiation in Escherichia coli

Ribosomal RNA (rRNA) contains a number of modified nucleosides in functionally important regions including the intersubunit bridge regions. As the activity of ribosome recycling factor (RRF) in separating the large and the small subunits of the ribosome involves disruption of intersubunit bridges, we investigated the impact of rRNA methylations on ribosome recycling. We show that deficiency of rRNA methylations, especially at positions 1518 and 1519 of 16S rRNA near the interface with the 50S subunit and in the vicinity of the IF3 binding site, adversely affects the efficiency of RRF-mediated ribosome recycling. In addition, we show that a compromise in the RRF activity affords increased initiation with a mutant tRNA(fMet) wherein the three consecutive G-C base pairs ((29)GGG(31):39CCC41), a highly conserved feature of the initiator tRNAs, were mutated to those found in the elongator tRNA(Met) ((29)UCA(31):(39)psi GA(41)). This observation has allowed us to uncover a new role of RRF as a factor that contributes to fidelity of initiator tRNA selection on the ribosome. We discuss these and earlier findings to propose that RRF plays a crucial role during all the steps of protein synthesis.

Molecular and serological detection of A. centrale- and A. marginale-infected cattle grazing within an endemic area

A reverse line blot hybridization (RLB) one-stage nested PCR (nPCR) for Anaplasma centrale and a nested PCR for Anaplasma marginale were used to detect infected cattle grazing within an endemic region in Israel. A novel set of PCR primers and oligonucleotide probes based on a 16S ribosomal RNA gene was designed for RLB detection of both Anaplasma species, and the performance of the molecular assays compared. The immunofluorescent antibody test (IFA) was used to detect antibodies to both Anaplasma species, whereas, a highly sensitive and specific competitive enzyme-linked immunosorbent assay (cELISA) was used to detect antibodies in A. centrale-vaccinated cattle. The RLB and the nested PCR procedures showed bacteremia with sensitivity of 50 infected erythrocytes per milliliter. Up to 93% of the A. centrale vaccinates carried specific antibodies that were detected by cELISA, and up to 71% of the vaccinated cattle were found to be naturally infected with A. marginale according to the PCR and the RLB assays. Nevertheless, no severe outbreaks of A. marginale infection occurred among vaccinated herds in this endemic region. It appears that both, molecular tools and serology are useful for evaluation of the vaccine efficacy. In the light of wide natural field infection with A. marginale, strong recommendations to continue the A. centrale vaccination program regime will continue until a new generation of non-blood-based vaccine will be developed.

Identification of a novel nucleolin related protein (NRP) gene expressed during rat spermatogenesis

Nucleolin is a major nucleolar phosphoprotein involved in various steps of ribosome biogenesis in eukaryotic cells. As nucleolin plays a significant role in ribosomal RNA transcription we were interested in examining in detail the expression of nucleolin across different stages of spermatogenesis and correlate with the transcription status of ribosomal DNA in germ cells.

Rhizoctonia solani as a potato pathogen : Variation of isolates in Finland and host response

Rhizoctonia solani is a soil inhabiting basidiomycetous fungus able to induce a wide range of symptoms in many plant species. This genetically complex species is divided to 13 anastomosis groups (AG), of which AG-3 is specialized to infect potato. However, also a few other AGs are able to infect or live in close contact with potato. On potato, R. solani infection causes two main types of diseases including stem canker observed as a dark brown lesions on developing stems and stolons, and black scurf that develops on new tubers close to the time of harvest. These disease symptoms are collectively called a ‘Rhizoctonia disease complex’. Between the growing seasons R. solani survives in soil and plant debri as sclerotia or as the sclerotia called black scurf on potato tubers which when used as seed offer the main route for dispersal of the fungus to new areas. The reasons for the dominance of AG-3 on potato seem to be attributable to its highly specialization to potato and its ability to infect and form sclerotia efficiently at low temperatures. In this study, a large nationwide survey of R. solani isolates was made in potato crops in Finland. Almost all characterized isolates belonged to AG-3. Additionally, three other AGs (AG-2-1, AG-4 and AG-5) were found associated with symptoms on potato plants but they were weaker pathogens on potato than AG-3 as less prone to form black scurf. According to phylogenetic analysis of the internal transcribed sequences (ITS) of the ribosomal RNA genes the Finnish AG-3 isolates are closely related to each other even though a wide variation of physiological features was observed between them. Detailed analysis of the ITS regions revealed single nucleotide polymorphism in 14 nucleotide positions of ITS-1 and ITS-2. Additionally, compensatory base changes on ITS-2 were detected which suggests that potato-infecting R. solani AG-3 could be considered as a separate species instead of an AG of R. solani. For the first time, molecular defence responses were studied and detected during the early phases of interaction between R. solani AG-3 and potato. Extensive systemic signalling for defence exploiting several known defence pathways was activated as soon as R. solani came into close contact with the base of a sprout. The defence response was strong enough to protect vulnerable sprout tips from new attacks by the pathogen. These results at least partly explain why potato emergence is eventually successful even under heavy infection pressure by R. solani.

Three new species of Tilletia on Eriachne from north-western Australia

Three new species of Tilletia are described from species of Eriachne (Poaceae) in the arid tropics of north-western Australia. In Western Australia, T. mactaggartii sp. nov. infects E. burkittii, and T. geeringii sp. nov. infects E. festucacea. Tilletia marjaniae sp. nov. infects E. pulchella subsp. dominii in Western Australia and the Northern Territory. These species are the first records of Tilletia on Eriachne. Phylogenetic relationships of these species were inferred from internal transcribed spacer of ribosomal RNA region and large subunit ribosomal RNA gene sequences.

A retrospective study of Babesia macropus associated with morbidity and mortality in eastern grey kangaroos (Macropus giganteus) and agile wallabies (Macropus agilis)

This is a retrospective study of 38 cases of infection by Babesia macropus, associated with a syndrome of anaemia and debility in hand-reared or free-ranging juvenile eastern grey kangaroos (Macropus giganteus) from coastal New South Wales and south-eastern Queensland between 1995 and 2013. Infection with B. macropus is recorded for the first time in agile wallabies (Macropus agilis) from far north Queensland. Animals in which B. macropus infection was considered to be the primary cause of morbidity had marked anaemia, lethargy and neurological signs, and often died. In these cases, parasitised erythrocytes were few or undetectable in peripheral blood samples but were sequestered in large numbers within small vessels of visceral organs, particularly in the kidney and brain, associated with distinctive clusters of extraerythrocytic organisms. Initial identification of this piroplasm in peripheral blood smears and in tissue impression smears and histological sections was confirmed using transmission electron microscopy and molecular analysis. Samples of kidney, brain or blood were tested using PCR and DNA sequencing of the 18S ribosomal RNA and heat shock protein 70 gene using primers specific for piroplasms. The piroplasm detected in these samples had 100 sequence identity in the 18S rRNA region with the recently described Babesia macropus in two eastern grey kangaroos from New South Wales and Queensland, and a high degree of similarity to an unnamed Babesia sp. recently detected in three woylies (Bettongia penicillata ogilbyi) in Western Australia.

Placental infection with Ureaplasma species is associated with histologic chorioamnionitis and adverse outcomes in moderately preterm and late-preterm infants

Objective The human Ureaplasma species are the microbes most frequently isolated from placentae of women who deliver preterm. The role of Ureaplasma species has been investigated in pregnancies at <32 weeks of gestation, but currently no studies have determined the prevalence of ureaplasmas in moderately preterm and late-preterm (hereafter, “moderate/late preterm”) infants, the largest cohort of preterm infants. Methods Women delivering moderate/late preterm infants (n = 477) and their infants/placentae (n = 535) were recruited, and swab specimens of chorioamnion tissue, chorioamnion tissue specimens, and cord blood specimens were obtained at delivery. Swab and tissue specimens were cultured and analyzed by 16S ribosomal RNA polymerase chain reaction (PCR) for the presence of microorganisms, while cord blood specimens were analyzed for the presence of cytokines, chemokines, and growth factors. Results We detected microorganisms in 10.6% of 535 placentae (443 were delivered late preterm and 92 were delivered at term). Significantly, Ureaplasma species were the most prevalent microorganisms, and their presence alone was associated with histologically confirmed chorioamnionitis in moderate/late preterm and term placentae (P < .001). The presence of ureaplasmas in the chorioamnion was also associated with elevated levels of granulocyte colony-stimulating factor (P = .02). Conclusions These findings have important implications for infection and adverse pregnancy outcomes throughout gestation and should be of major consideration for obstetricians and neonatologists.

Rate of ribonucleic acid chain growth in Mycobacterium tuberculosis H37Rv.

Two methods were employed to measure the rate of ribonucleic acid (RNA) chain growth in vivo in Mycobacterium tuberculosis H37Rv cultures growing in Sauton medium at 37 degrees C, with a generation time of 10 h. In the first, the bacteria were allowed to assimilate [3H]uracil or [3H]guanine into their RNA for short time periods. The RNA was then extracted and hydrolyzed with alkali, and the radioactivity in the resulting nucleotides and nucleosides was measured. The data obtained by this method allowed the calculation of the individual nucleotide step times during the growth of RNA chains, from which the average rate of RNA chain elongation was estimated to be about 4 nucleotides per s. The second method employed the antibiotic rifampin, which specifically inhibits the initiation of RNA synthesis without interfering with the elongation and completion of nascent RNA chains. Usint this method, the transcription time of the 16S, 23S, and 5S ribosomal RNA genes was estimated to be 7.6 min, which corresponds to a ribosomal RNA chain growth rate of 10 nucleotides per s.

Archaea, Bacteria, and methane production along environmental gradients in fens and bogs

Metanogeenit ovat hapettomissa oloissa eläviä arkkien pääryhmään kuuluvia mikrobeja, joiden ainutlaatuisen aineenvaihdunnan seurauksena syntyy metaania. Ilmakehässä metaani on voimakas kasvihuonekaasu. Yksi suurimmista luonnon metaanilähteistä ovat kosteikot. Pohjoisten soiden metaanipäästöt vaihtelevat voimakkaasti eri soiden välillä ja yhden suon sisälläkin, riippuen muun muassa vuodenajasta, suotyypistä ja kasvillisuudesta. Väitöskirjatyössä tutkittiin metaanipäästöjen vaihtelun mikrobiologista taustaa. Tutkimuksessa selvitettiin suotyypin, vuodenajan, tuhkalannoituksen ja turvesyvyyden vaikutusta metanogeeniyhteisöihin sekä metaanintuottoon kolmella suomalaisella suolla. Lisäksi tutkittiin ei-metanogeenisia arkkeja ja bakteereita, koska ne muodostavat metaanin tuoton lähtöaineet osana hapetonta hajotusta. Mikrobiyhteisöt analysoitiin DNA- ja RNA-lähtöisillä, polymeraasiketjureaktioon (PCR) perustuvilla menetelmillä. Merkkigeeneinä käytettiin metaanin tuottoon liittyvää mcrA-geeniä sekä arkkien ja bakteerien ribosomaalista 16S RNA-geeniä. Metanogeeniyhteisöt ja metaanintuotto erosivat huomattavasti happaman ja vähäravinteisen rahkasuon sekä ravinteikkaampien sarasoiden välillä. Rahkasuolta löytyi lähes yksinomaan Methanomicrobiales-lahkon metanogeeneja, jotka tuottavat metaania vedystä ja hiilidioksidista. Sarasoiden metanogeeniyhteisöt olivat monimuotoisempia, ja niillä esiintyi myös asetaattia käyttäviä metanogeeneja. Vuodenaika vaikutti merkittävästi metaanintuottoon. Talvella havaittiin odottamattoman suuri metaanintuottopotentiaali sekä viitteitä aktiivisista metanogeeneista. Arkkiyhteisön koostumus sen sijaan vaihteli vain vähän. Tuhkalannoitus, jonka tarkoituksena on edistää puiden kasvua ojitetuilla soilla, ei merkittävästi vaikuttanut metaanintuottoon tai -tuottajiin. Ojitetun suon yhteisöt kuitenkin muuttuivat turvesyvyyden mukaan. Vertailtaessa erilaisia PCR-menetelmiä todettiin, että kolmella mcrA-geeniin kohdistuvalla alukeparilla havaittiin pääosin samat ojitetun suon metanogeenit, mutta lajien runsaussuhteet riippuvat käytetyistä alukkeista. Soilla havaitut bakteerit kuuluivat pääjaksoihin Deltaproteobacteria, Acidobacteria ja Verrucomicrobia. Lisäksi löydettiin Crenarchaeota-pääjakson ryhmiin 1.1c ja 1.3 kuuluvia ei-metanogeenisia arkkeja. Tulokset ryhmien esiintymisestä hapettomassa turpeessa antavat lähtökohdan selvittää niiden mahdollisia vuorovaikutuksia metanogeenien kanssa. Tutkimuksen tulokset osoittivat, että metanogeeniyhteisön koostumus heijastaa metaanintuottoon vaikuttavia kemiallisia tai kasvillisuuden vaihteluita kuten suotyyppiä. Soiden metanogeenien ja niiden fysiologian parempi tuntemus voi auttaa ennustamaan ympäristömuutosten vaikutusta soiden metaanipäästöihin.

Impact of resistance exercise on ribosome biogenesis is acutely regulated by post-exercise recovery strategies

Muscle hypertrophy occurs following increased protein synthesis, which requires activation of the ribosomal complex. Additionally, increased translational capacity via elevated ribosomal RNA (rRNA) synthesis has also been implicated in resistance training-induced skeletal muscle hypertrophy. The time course of ribosome biogenesis following resistance exercise (RE) and the impact exerted by differing recovery strategies remains unknown. In the present study, the activation of transcriptional regulators, the expression levels of pre-rRNA, and mature rRNA components were measured through 48 h after a single-bout RE. In addition, the effects of either low-intensity cycling (active recovery, ACT) or a cold-water immersion (CWI) recovery strategy were compared. Nine male subjects performed two bouts of high-load RE randomized to be followed by 10 min of either ACT or CWI. Muscle biopsies were collected before RE and at 2, 24, and 48 h after RE. RE increased the phosphorylation of the p38-MNK1-eIF4E axis, an effect only evident with ACT recovery. Downstream, cyclin D1 protein, total eIF4E, upstream binding factor 1 (UBF1), and c-Myc proteins were all increased only after RE with ACT. This corresponded with elevated abundance of the pre-rRNAs (45S, ITS-28S, ITS-5.8S, and ETS-18S) from 24 h after RE with ACT. In conclusion, coordinated upstream signaling and activation of transcriptional factors stimulated pre-rRNA expression after RE. CWI, as a recovery strategy, markedly blunted these events, suggesting that suppressed ribosome biogenesis may be one factor contributing to the impaired hypertrophic response observed when CWI is used regularly after exercise.

The complete mitochondrial genome of the eastern grey kangaroo (Macropus giganteus)

We present the complete mitochondrial genome (accession number: LK995454) of an iconic Australian species, the eastern grey kangaroo (Macropus giganteus). The mitogenomic organization is consistent with other marsupials, encoding 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, an origin of light strand replication and a control region or Dloop. No repetitive sequences were detected in the control region. The M. giganteus mitogenome exemplifies a combination of tRNA gene order and structural peculiarities that appear to be unique to marsupials. We present a maximum likelihood phylogeny based on complete mitochondrial protein and RNA coding sequences that confirms the phylogenetic position of the grey kangaroo among macropodids.