Singlet oxygen quenching and the redox properties of hydroxycinnamic acids

The singlet oxygen quenching rate constants (kq) for a range of hydroxycinnamic acids in acetonitrile and D2O solutions were measured using time resolved near infrared phosphorescence in order to establish their antioxidant activity. The magnitude of kq observed depends on both the nature of the substituent groups and solvent polarity. The variations in kq depend on the energy of the hydroxycinnamic acid/molecular oxygen charge transfer states, (O2delta- ...HCAdelta+). In D2O the values of kq range from 4x10(7) M(-1) s(-1) to 4x10(6) M(-1) s(-1) for caffeic acid and o-coumaric acid respectively. In acetonitrile, the charge transfer energy levels are raised and this is reflected in lower singlet oxygen quenching rate constants with a kq value of 5x10(6) M(-1) s(-1) for caffeic acid. The phenoxyl radical spectra derived from the hydroxycinnamic acids were determined using pulse radiolysis of aqueous solutions and the reduction potentials were found to range from 534 to 596 mV. A linear correlation is observed between reduction potential, and hence free energy for electron transfer, and log kq. These correlations suggest a charge transfer mechanism for the quenching of singlet oxygen by the hydroxycinnamic acids.

High-resolution magnification endoscopy can reliably identify normal gastric mucosa, Helicobacter pylori-associated gastritis, and gastric atrophy

BACKGROUND AND STUDY AIMS

The aims of the study were to describe the magnified endoscopic findings in the gastric body, correlate these with histology, and evaluate their reproducibility in the assessment of the magnified endoscopic patterns seen.

PATIENTS AND METHODS

A total of 95 consecutive dyspeptic patients underwent upper gastrointestinal endoscopy with a magnifying endoscope. The endoscopists classified the magnified endoscopic patterns and correlated them with the histological findings. In the second part of the study, 200 images were shown to five endoscopists in order to examine inter- and intraobserver variability in image assessment.

RESULTS

The magnified endoscopic findings in the gastric body were categorized into four types: type 1, honeycomb-type subepithelial capillary network (SECN) with regular arrangement of collecting venules and regular, round pits; type 2, honeycomb-type SECN with regular, round pits, but loss of collecting venules; type 3, loss of normal SECN and collecting venules, with enlarged white pits surrounded by erythema; and type 4, loss of normal SECN and round pits, with irregular arrangement of collecting venules. The sensitivity, specificity, and positive and negative predictive values of the type 1 pattern for predicting normal gastric mucosa were 92.7% (95% confidence interval [CI] 93.2-97.3%), 100% (95% CI 83.9-100%), 100% (95% CI 92.9-100%), and 83.8% (95% CI 65.5-93.9%). The sensitivity, specificity, and positive and negative predictive values of types 2 and 3 patterns for predicting a Helicobacter pylori-infected stomach were 100% (95% CI 83.9-100%), 92.7% (95% CI 93.2-97.3%), 83.8% (95% CI 65.5-93.9%), and 100% (95% CI 92.9-100%). The sensitivity, specificity, and positive and negative predictive values of a type 4 pattern for predicting gastric atrophy were 90% (95% CI 66.8-98.2%), 96% (95% CI 87.9-98.9%), 85.7% (95% CI 62.6-96.2%), and 97.3% (95% CI 89.6-99.5%. The kappa values for inter- and intraobserver agreement in predicting normal gastric mucosa, H. pylori gastritis, and gastric atrophy were 0.864 and 0.913 respectively.

CONCLUSION

High-resolution magnification endoscopy can reliably identify the normal gastric mucosa, H. pylori-associated gastritis, and gastric atrophy in a Western population.

Distinct and overlapping functions of allelic forms of human mannose binding protein

Human mannose binding protein (MBP) is a C-type serum lectin involved in first-line host defense against a variety of bacterial, fungal and viral pathogens. Recently an association was found between low levels of serum MBP and an increased frequency of recurrent infections in infants. A particular genotype, in which glycine is substituted by aspartic acid at codon 54 of MBP in the fifth collagen repeat, shows apparent concordance with the clinical phenotype. We report, however, that this genotype occurs in 5% of the population and encodes a functional protein. Our results indicate that the Gly54Asp allele does not account for a deficiency state, but instead suggest that MBP may have two predominant allelic forms that have overlapping function and differ only in their ability to activate the classical pathway of complement.

Distinct receptor and regulatory properties of recombinant mouse complement receptor 1 (CR1) and Crry, the two genetic homologues of human CR1

The relationship between the characterized mouse regulators of complement activation (RCA) genes and the 190-kD mouse complement receptor 1 (MCR1), 155-kD mouse complement receptor 2 (MCR2), and mouse p65 is unclear. One mouse RCA gene, designated MCR2 (or Cr2), encodes alternatively spliced 21 and 15 short consensus repeat (SCR)-containing transcripts that crosshybridize with cDNAs of both human CR2 and CR1, or CR2 alone, respectively. A five SCR-containing transcript derived from a second unique gene, designated Crry, also crosshybridizes with human CR1. We have previously shown that the 155-kD MCR2 is encoded by the 15 SCR-containing transcript. To analyze the protein products of the other transcripts, which are considered the genetic homologues of human CR1, we have expressed the 21 and the 5 SCR-containing cDNAs in the human K562 erythroleukemia cell line. We demonstrate that cells expressing the 21 SCR transcript express the 190-kD MCR1 protein. These cells react with five unique rat anti-MCR1 monoclonal antibodies, including the 8C12 antibody considered to be monospecific for MCR1. In addition, these cells efficiently form rosettes with mouse C3b-bearing sheep erythrocytes. In contrast, cells expressing the five SCR-containing Crry transcript are strongly recognized by an anti-human CR1 antibody that also defines the mouse p65 protein. Using a functional assay that measures the surface deposition of C3 activated via the classical complement pathway, we show that Crry/p65-expressing cells have a markedly decreased amount of C3 deposited on them as compared with control cells expressing the antisense construct or cells expressing MCR1 or MCR2. This suggests that Crry has intrinsic complement regulatory activity.(ABSTRACT TRUNCATED AT 250 WORDS)

The EGF-CFC family: novel epidermal growth factor-related proteins in development and cancer

The EGF-CFC gene family encodes a group of structurally related proteins that serve as important competence factors during early embryogenesis in Xenopus, zebrafish, mice and humans. This multigene family consists of Xenopus FRL-1, zebrafish one-eyed-pinhead (oep), mouse cripto (Cr-1) and cryptic, and human cripto (CR-1) and criptin. FRL-1, oep and mouse cripto are essential for the formation of mesoderm and endoderm and for correct establishment of the anterior/posterior axis. In addition, oep and cryptic are important for the establishment of left-right (L/R) asymmetry. In zebrafish, there is strong genetic evidence that oep functions as an obligatory co-factor for the correct signaling of a transforming growth factor-beta (TGFbeta)-related gene, nodal, during gastrulation and during L/R asymmetry development. Expression of Cr-1 and cryptic is extinguished in the embryo after day 8 of gestation except for the developing heart where Cr-1 expression is necessary for myocardial development. In the mouse, cryptic is not expressed in adult tissues whereas Cr-1 is expressed at a low level in several different tissues including the mammary gland. In the mammary gland, expression of Cr-1 in the ductal epithelial cells increases during pregnancy and lactation and immunoreactive and biologically active Cr-1 protein can be detected in human milk. Overexpression of Cr-1 in mouse mammary epithelial cells can facilitate their in vitro transformation and in vivo these Cr-1-transduced cells produce ductal hyperplasias in the mammary gland. Recombinant mouse or human cripto can enhance cell motility and branching morphogenesis in mammary epithelial cells and in some human tumor cells. These effects are accompanied by an epithelial-mesenchymal transition which is associated with a decrease in beta-catenin function and an increase in vimentin expression. Expression of cripto is increased several-fold in human colon, gastric, pancreatic and lung carcinomas and in a variety of different types of mouse and human breast carcinomas. More importantly, this increase can first be detected in premalignant lesions in some of these tissues. Although a specific receptor for the EGF-CFC proteins has not yet been identified, oep depends upon an activin-type RIIB and RIB receptor system that functions through Smad-2. Mouse and human cripto have been shown to activate a ras/raf/MAP kinase signaling pathway in mammary epithelial cells. Activation of phosphatidylinositol 3-kinase and Akt are also important for the ability of CR-1 to stimulate cell migration and to block lactogenic hormone-induced expression of beta-casein and whey acidic protein. In mammary epithelial cells, part of these responses may depend on the ability of CR-1 to transactivate erb B-4 and/or fibroblast growth factor receptor 1 through an src-like tyrosine kinase.

Characterization of the lysogeny DNA module from the temperate Streptococcus thermophilus bacteriophage phi Sfi21

Phage phi Sfi21, the only temperate Streptococcus thermophilus phage from our phage collection, showed extensive DNA homology with virulent phages from lytic group I. Southern blot hybridizations demonstrated that the phi Sfi21-specific DNA was clustered in an approximately 6.6-kb-long region, the putative lysogeny module. Sequence analysis and database research identified an integrase within this module; orf 203 with homology to an anonymous orf 258 from the temperate lactococcal phage BK5-T; orf 127 and orf 122 with weak homology to the N- and C-terminal parts, respectively, of the cl-like repressor from lactococcal phages Tuc2009 and BK5-T; orf 75 with homology to a repressor protein from lambdoid phage 434 and an anti-repressor ant with homology to phage P1. The molecular arrangement of the predicted orfs in phage phi Sfi21 was very similar to that of the lactococcal phage BK5-T. The transition from phi Sfi21-specific DNA into DNA shared with virulent phages was abrupt and flanked at one side by notable DNA repeats. Sequence analysis identified a holin protein to the left of the lysogeny module. A site-specific deletion of 2.4 kb, which reproducibly transformed phi Sfi21 into a lytic phage, was localized in the lysogeny module. It was flanked at both sides by conspicuous DNA repeats. One repeat region reflected the DNA around the attP site, while the other reflected the putative genetic switch region between repressor and anti-repressor genes. S. thermophilus host Sfi1 transformed with a plasmid containing int and orf 203 showed resistance to superinfection by heterologous phages, but not by the homologous phi Sfi21. Part of the int gene could be deleted without loss of this activity, while a deletion in orf 203 resulted in loss of the phage resistance. We speculate on the possibility of a bipartite immunity system for the control of lysogeny in phi Sfi21.

Reduced intensity allogeneic umbilical cord blood transplantation in children and adolescent recipients with malignant and non-malignant diseases

There is a significant amount of morbidity and mortality following myeloablative umbilical cord blood transplantation (UCBT). Reduced intensity (RI) conditioning offers an alternative to myeloablative conditioning before UCBT. We investigated RI-UCBT in 21 children and adolescents with malignant (n=14), and non-malignant diseases (n=7). RI conditioning consisted of fludarabine (150-180 mg/m2) with either busulfan (< or = 8 mg/kg)+rabbit antithymocyte globulin (R-ATG; n=16) or cyclophosphamide+R-ATG+/-etoposide (n=5). Human leukocyte antigen match: 4/6 (n=13), 5/6 (n=5) and 6/6 (n=3). The median total nucleated cell and CD34+ cell dose per kilogram were 3.58 x 10(7) and 2.54 x 10(5), respectively. The median time for neutrophil and platelet engraftment was 17.5 and 52 days, respectively. There were six primary graft failures (chronic myelogenous leukemia (CML), beta-thalassemia, hemophagocytic lymphohistiocytosis (HLH) and myelodysplastic syndrome (MDS)). The probability of developing grade II to grade IV acute graft-versus-host disease (GVHD) and chronic GVHD was 28.6 and 16.7%, respectively. Incidence of transplant-related mortality (TRM) was 14%. The 5 years overall survival (OS) in all patients was 59.8%. The 5 years OS for patients with average versus poor-risk malignancy was 77.8 versus 22.2% (P=0.03). RI-UCBT may result in graft failure in specific high-risk chemo-naïve patients (CML, beta-thalassemia, HLH and MDS), but in more heavily pretreated pediatric and adolescent recipients results in rapid engraftment and may be associated with decreased severe GVHD and TRM.

Long-term suprapubic catheterisation: clinical outcome and satisfaction survey

We report on the clinical outcome and satisfaction survey of long-term suprapubic catheterisation in patients with neuropathic bladder dysfunction. Between early 1988 and later 1995, 185 suprapubic catheters were inserted under direct cystoscopic vision. Anti-cholinergic therapy was given to all patients with significant detrusor hyper-reflexia; the catheters clamped daily for two hours and changed every six weeks. Ultrasonography and assessment of the serum creatinine were used to assess the upper renal tracts, and the results of the pre- and post-catheter video-cystometrography was used to evaluate bladder morphology, cystometric capacity, maximum detrusor pressure and the presence of vesico-ureteric reflux. There were equivalent numbers of males and females. The follow-up ranges from 3-68 months. Following catheterisation, there was a 50% reduction in the average maximum detrusor pressure, bladder morphology improved in 85% of the cases; the bladder capacity and upper renal tracts remained unchanged. Vesico-ureteric reflux was abolished in 33% of the cases. Complaints were common consisting of recurrent catheter blockage, persistent urinary leakage and recurrent urinary tract infections. There was a 2.7% incidence of small bowel injury with one fatality. However, the general level of satisfaction was high. It is concluded that suprapubic catheterisation is an effective and well tolerated method of management in selected patients with neuropathic bladder dysfunction for whom only major surgery would otherwise provide a solution to incontinence. We are encouraged to find preservation of renal function with maintained bladder volumes and reduced maximum detrusor pressures thus justifying the policy of catheter clamping and anti-cholinergic therapy in the presence of significant detrusor hyper-reflexia. However, even in expert hands this procedure is not without hazards.

Fucosylation of Cripto is required for its ability to facilitate nodal signaling

O-linked fucose modification is rare and has been shown to occur almost exclusively within epidermal growth factor (EGF)-like modules. We have found that the EGF-CFC family member human Cripto-1 (CR) is modified with fucose and through a combination of peptide mapping, mass spectrometry, and sequence analysis localized the site of attachment to Thr-88. The identification of a fucose modification on human CR within its EGF-like domain and the presence of a consensus fucosylation site within all EGF-CFC family members suggest that this is a biologically important modification in CR, which functionally distinguishes it from the EGF ligands that bind the type 1 erbB growth factor receptors. A single CR point mutation, Thr-88 --> Ala, results in a form of the protein that is not fucosylated and has substantially weaker activity in cell-based CR/Nodal signaling assays, indicating that fucosylation is functionally important for CR to facilitate Nodal signaling.

Iron-induced mucosal pathology of the upper gastrointestinal tract: a common finding in patients on oral iron therapy

AIMS

Upper gastrointestinal injury from iron tablets at therapeutic dose is not widely recognized. The aim was to document cases of iron-related upper gastrointestinal (GI) pathology and to determine frequency of occurrence.

METHODS AND RESULTS

We prospectively studied patients with iron deficiency anaemia undergoing upper GI endoscopy from November 2005 to July 2006. Cases of upper GI iron deposition from these and other cases extracted retrospectively between 1999 and 2006 were examined histopathologically and patient notes were reviewed. In the prospective study, 15/160 patients investigated for iron deficiency anaemia [16.1% (15/93) of those taking oral iron tablets] had iron deposition noted on routine haematoxylin and eosin staining. In this plus the retrospective series, 59 patients were identified with 64 episodes of iron deposition. Eighty-six percent (6/7) with oesophageal iron deposition had associated erosion. Sixty-three percent (29/46) with gastric iron deposition had erosion and 80% (37/46) had reactive gastritis. Duodenal deposition was usually (91%, 10/11) within macrophages in villous tips with no erosion. Ninety-eight percent (58/59) of iron deposition cases had documented oral iron intake.

CONCLUSIONS

Iron deposition in the upper GI tract is common in patients taking iron tablets. It is frequently associated with mucosal disruption in the oesophagus and stomach.

Zebrafish pitx3 is necessary for normal lens and retinal development

The human PITX3 gene encodes a bicoid-like homeodomain transcription factor associated with a variety of congenital ocular conditions, including anterior segment dysgenesis, Peter's anomaly, and cataracts. We identified a zebrafish pitx3 gene encoding a protein (Pitx3) that possesses 63% amino acid identity with human PITX3. The zebrafish pitx3 gene encompasses approximately 16.5kb on chromosome 13 and consists of four exons, which is similar to the genomic organization of other pitx genes. Expression of the zebrafish pitx3 gene was studied by in situ mRNA hybridization and RT-PCR. The pitx3 transcripts were detected throughout development with the greatest level of expression occurring in the developing lens and brain at 24hpf. In adults, the highest expression was detected in the eye. Morpholinos were used to knockdown expression of the Pitx3 protein and a control morpholino that contains five mismatched bases was used to confirm the specificity of the phenotypes. The morphants had small eyes, misshapen heads and reduced jaws and fins relative to controls. The morphants exhibited abnormalities in lens development and their retinas contained pyknotic nuclei accompanied by a reduction in the number of cells in different neuronal classes. This suggests the lens is required for retinal development or Pitx3 has an unexpected role in retinal cell differentiation or survival. These results demonstrate zebrafish pitx3 represents a true ortholog of the human PITX3 gene and the general function of the Pitx3 protein in lens development is conserved between mammals and the teleost fish.

Mouse Crry/p65 is a regulator of the alternative pathway of complement activation

Like man, mouse has evolved a unique set of regulatory proteins which provide protection from complement-mediated damage to self membranes. The recently described mouse protein Crry/p65 has been shown to inhibit classical complement pathway C3 deposition on cell membranes in which it is expressed. In two distinct experimental systems, we now further delineate the regulatory activity of Crry/p65 and demonstrate its inhibitory effect on alternative complement pathway C3 activation. First, significant inhibition of mouse alternative pathway C3 deposition was demonstrated on neuraminidase-treated human K562 cells expressing recombinant Crry/p65. Second, using a baculovirus technique, recombinant Crry/p65 was synthesized as a soluble molecule and then purified. This molecule was found to inhibit mouse C3 deposition on the surface of zymosan, a potent alternative complement pathway activator. These studies, combined with our earlier findings, demonstrate that Crry/p65 can regulate both the classical and alternative complement pathways. Crry/p65 must, therefore, exert its effects prior to, or at the level of, the C3 convertases, in a fashion similar to that of human membrane cofactor protein and/or decay-accelerating factor. These studies provide further proof of the hypothesis that Crry/p65 is an evolutionarily unique, complement regulatory protein which has developed in mouse.

Widespread distribution of a group I intron and its three deletion derivatives in the lysin gene of Streptococcus thermophilus bacteriophages

Of 62 Streptococcus thermophilus bacteriophages isolated from various ecological settings, half contain a lysin gene interrupted by a group IA2 intron. Phage mRNA splicing was demonstrated. Five phages possess a variant form of the intron resulting from three distinct deletion events located in the intron-harbored open reading frame (orf 253). The predicted orf 253 gene sequence showed a significantly lower GC content than the surrounding intron and lysin gene sequences, and the predicted protein shared a motif with endonucleases found in phages from both gram-positive and gram-negative bacteria. A comparison of the phage lysin genes revealed a clear division between intron-containing and intron-free alleles, leading to the establishment of a 14-bp consensus sequence associated with intron possession. The conserved intron was not found elsewhere in the phage or S. thermophilus bacterial genomes. Folding of the intron RNA revealed secondary structure elements shared with other phage introns: first, a 38-bp insertion between regions P3 and P4 that can be folded into two stem-loop structures (shared with introns from Bacillus phage SPO1 and relatives); second, a conserved P7.2 region (shared with all phage introns); third, the location of the stop codon from orf 253 in the P8 stem (shared with coliphage T4 and Bacillus phage SPO1 introns); fourth, orf 253, which has sequence similarity with the H-N-H motif of putative endonuclease genes found in introns from Lactococcus, Lactobacillus, and Bacillus phages.

Acetic acid-enhanced magnification endoscopy in the diagnosis of specialized intestinal metaplasia, dysplasia and early cancer in Barrett's oesophagus

BACKGROUND

Barrett's surveillance is prone to sampling error. Aim To determine whether enhanced magnification endoscopy using acetic acid instillation improves diagnostic accuracy of specialized intestinal metaplasia/dysplasia in Barrett's oesophagus.

METHODS

We examined the detection rate of the specialized intestinal metaplasia/dysplasia in 64 consecutive patients with Barrett's oesophagus using acetic acid to enhance mucosal pit patterns. Histology was compared with the previous findings at recent conventional surveillance in 62 patients. We also examined the inter-/intra-observer agreement in the assessment of the enhanced magnification endoscopy pit pattern findings.

RESULTS

Histology revealed columnar-lined oesophagus in six (9%) patients, specialized intestinal metaplasia in 49 (77%), low-grade dysplasia in five (8%), high-grade dysplasia in one (2%), and adenocarcinoma in three (5%). There was discordance between the histologic findings from conventional surveillance with random biopsy. Fifteen patients (24%) had a histological upgrade with enhanced magnification endoscopy. There was a high detection rate of specialized intestinal metaplasia even in short segment Barrett's oesophagus (74%), and additionally, there were two cancers, one with 2-cm Barrett's oesophagus and one ultra-short (1 cm). The mean kappa values for inter- and intra-observer agreement in assessing the pit patterns were 0.571 (0.041) and 0.709 (0.038), respectively.

CONCLUSIONS

Enhanced magnification endoscopy allows clear visualization of the epithelial pit patterns within Barrett's oesophagus, and targeted biopsy results in a high yield of specialized intestinal metaplasia and dysplasia.

Neuronal molecular mimicry in immune-mediated neurologic disease

Molecular mimicry is implicated in the pathogenesis of autoimmune diseases such as diabetes mellitus, rheumatoid arthritis, and multiple sclerosis (MS). Cellular and antibody-mediated immune responses to shared viral-host antigens have been associated with the development of disease in these patients. Patients infected with human T-lymphotropic virus type I (HTLV-I) develop HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), an immune-mediated disorder of the central nervous system (CNS) that resembles some forms of MS. Damage to neuronal processes in the CNS of HAM/TSP patients is associated with an activated cellular and antibody-mediated immune response. In this study, IgG isolated from HAM/TSP patients was immunoreactive with uninfected neurons and this reactivity was HTLV-I specific. HAM/TSP IgG stained uninfected neurons in human CNS and cell lines but not nonneuronal cells. Neuronal western blots showed IgG reactivity with a single 33-kd band in all HAM/TSP patients tested. By contrast, no neuron-specific IgG reactivity could be demonstrated from HTLV-I seronegative controls and, more important, from HTLV-I seropositive, neurologically asymptomatic individuals. Both immunocytochemical staining and western blot reactivity were abolished by preincubating HAM/TSP IgG with HTLV-I protein lysate but not by control proteins. Staining of CNS tissue by a monoclonal antibody to HTLV-I tax (an immunodominant HTLV-I antigen) mimicked HAM/TSP IgG immunoreactivity. There was no staining by control antibodies. Absorption of HAM/TSP IgG with recombinant HTLV-I tax protein or preincubation of CNS tissue with the monoclonal antibody to HTLV-I tax abrogated the immunocytochemical and western blot reactivity of HAM/TSP IgG. Furthermore, in situ human IgG localized to neurons in HAM/TSP brain but not in normal brain. These data indicate that HAM/TSP patients develop an antibody response that targets uninfected neurons, yet reactivity is blocked by HTLV-I, suggesting viral-specific autoimmune reactivity to the CNS, the damaged target organ in HAM/TSP.

A short noncoding viral DNA element showing characteristics of a replication origin confers bacteriophage resistance to Streptococcus thermophilus

A 302-bp noncoding DNA fragment from the DNA replication module of phage phiSfi21 was shown to protect the Streptococcus thermophilus strain Sfi1 from infection by 17 of 25 phages. The phage-inhibitory DNA possesses two determinants, each of which individually mediated phage resistance. The phage-inhibitory activity was copy number dependent and operates by blocking the accumulation of phage DNA. Furthermore, when cloned on a plasmid, the phiSfi21 DNA acts as an origin of replication driven by phage infection. Protein or proteins in the phiSfi21-infected cells were shown to interact with this phage-inhibitory DNA fragment, forming a retarded protein-DNA complex in gel retardation assays. A model in which phage proteins interact with the inhibitory DNA such that they are no longer available for phage propagation can be used to explain the observed bacteriophage resistance. Genome analysis of phiSfi19, a phage that is insensitive to the inhibitory activity of the phiSfi21-derived DNA, led to the characterisation of a variant putative phage replication origin that differed in 14 of 302 nucleotides from that of phiSfi21. The variant origin was cloned and exhibited an inhibitory activity toward phages that were insensitive to the phiSfi21-derived DNA.

Association between genetic risk scoring for schizophrenia and bipolar disorder with regional subcortical volumes

Previous research has shown coincident abnormal regional brain volume in patients with schizophrenia (SCZ) and bipolar disorder (BD) compared with controls. Whether these abnormalities are genetically driven or explained by secondary effects of the disorder or environmental factors is unknown. We aimed to investigate the association between genetic risk scoring (GRS) for SCZ and BD with volume of brain areas previously shown to be different between these clinical groups and healthy controls. We obtained subcortical brain volume measures and GRS for SCZ and BD from a sample of 274 healthy volunteers (71.4% females, mean age 24.7 (s.d. 6.9)). Volume of the globus pallidus was associated with the shared GRS between SCZ and BD, and also with the independent GRS for each of these disorders. Volume of the amygdala was associated with the non-shared GRS between SCZ and BD, and with the independent GRS for BD. Our results for volume of the globus pallidus support the idea of SCZ and BD sharing a common underlying neurobiological abnormality associated with a common genetic risk for both these disorders. Results for volume of the amygdala, though, would suggest the existence of a distinct mechanism only associated with genetic risk for BD. Finally, the lack of association between genetic risk and volume of most subcortical structures suggests that the volumetric differences reported in patient-control comparisons may not be genetically driven, but a consequence of the disorder or co-occurring environmental factors.

The site-specific integration system of the temperate Streptococcus thermophilus bacteriophage phiSfi21

The temperate bacteriophage phiSfi21 integrates its DNA into the chromosome of Streptococcus thermophilus strains via site-specific recombination. Nucleotide sequencing of the attachment sites identified a 40-bp identity region which surprisingly overlaps both the 18-terminal bp of the phage integrase gene and the 11-terminal bp of a host tRNAArg gene. A 2.4-kb phage DNA segment, covering attP, the phage integrase, and a likely immunity gene contained all the genetic information for faithful integration of a nonreplicative plasmid into the attB site. A deletion within the int gene led to the loss of integration proficiency. A number of spontaneous deletions were observed in plasmids containing the 2.4-kb phage DNA segment. The deletion sites were localized to the tRNA side of the identity region and to phage or vector DNA with 3- to 6-bp-long repeats from the border region. A similar type of deletion was previously observed in a spontaneous phage mutant.