The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio (Asteraceae).

Ecological speciation, driven by adaptation to contrasting environments, provides an attractive opportunity to study the formation of distinct species, and the role of selection and genomic divergence in this process. Here, we focus on a particularly clear-cut case of ecological speciation to reveal the genomic bases of reproductive isolation and morphological differences between closely related Senecio species, whose recent divergence within the last ~200,000 years was likely driven by the uplift of Mt. Etna (Sicily). These species form a hybrid zone, yet remain morphologically and ecologically distinct, despite active gene exchange. Here, we report a high-density genetic map of the Senecio genome and map hybrid breakdown to one large and several small quantitative trait loci (QTL). Loci under diversifying selection cluster in three 5 cM regions which are characterized by a significant increase in relative (F(ST)), but not absolute (d(XY)), interspecific differentiation. They also correspond to some of the regions of greatest marker density, possibly corresponding to 'cold-spots' of recombination, such as centromeres or chromosomal inversions. Morphological QTL for leaf and floral traits overlap these clusters. We also detected three genomic regions with significant transmission ratio distortion (TRD), possibly indicating accumulation of intrinsic genetic incompatibilities between these recently diverged species. One of the TRD regions overlapped with a cluster of high species differentiation, and another overlaps the large QTL for hybrid breakdown, indicating that divergence of these species may have occurred due to a complex interplay of ecological divergence and accumulation of intrinsic genetic incompatibilities.

The most frequent cause of 90-day unplanned hospital readmission following colorectal cancer resection is chemotherapy complications.

AIM: NHS England deems 90-day readmission rates as a marker of quality of care. The causes of readmission have not been previously reported in the UK. The aim of this study was to examine the factors associated with 90-day readmission following colorectal cancer surgery at a hospital trust with a catchment population 1.2 million. METHOD: A retrospective review was performed of all patients undergoing resection for colorectal cancer between January 2012 and December 2013. Unplanned readmission was defined as an emergency admission to the trust for any cause within 90 days of surgery. Readmission analyses were restricted to patients discharged from hospital within 28 days of resection. RESULTS: A total of 570 patients underwent surgery, of whom 522 were discharged within 28 days and are included for readmission analysis. The readmission rate was 24.3% (127 patients with a total of 163 episodes of hospital readmissions) within 90 days following surgery. The most frequent cause for readmission was complications related to adjuvant chemotherapy (18.4%) followed by wound-related complications (14.1%). Most patients presenting with wound-related complications were admitted within 60 days and patients with chemotherapy-related complications after 61 days; 13/127 (10.2%) patients who were readmitted underwent emergency surgery, and one patient died following readmission. Multivariate analysis demonstrated that comorbidity was the only independent risk factor. CONCLUSION: Ninety-day readmissions include a high number of readmissions secondary to chemotherapy-related complications, whereas most surgical-related readmission present within 60 days.

Is whole colonic imaging necessary for symptoms of change in bowel habit and/or rectal bleeding?

AIM: Following the introduction of a 2-week-wait (2ww) cancer pathway, many units are triaging patients with change in bowel habit (CIBH) and/or rectal bleeding (RB) straight to colonoscopy. Evidence suggests that right-sided colonic cancer does not present with these symptoms, hence imaging the left colon only is satisfactory. If this were substantiated, patients could be offered a flexible sigmoidoscopy (FS) alone. This study aimed to review presenting symptoms of patients diagnosed with a right-sided colonic malignancy and assess whether their tumours would be missed based on this practice. METHOD: This is a retrospective analysis of patients who underwent curative resection for a proximal colonic malignancy over a 4-year period. Two-week-wait referral proforma and case notes were analysed for mode of presentation. RESULTS: Of 206 elective right hemicolectomies performed, 20/206 (9.7%) patients presented in the absence of either iron deficiency anaemia or palpable abdominal mass. Twelve patients had polyposis identified in the left colon and eight patients had no left-sided colonic pathology. One patient had a strong family history of colon cancer (two first-degree relatives) in the group absent of left-sided pathology. CONCLUSION: Twelve patients who had left-sided polyposis and one patient with a strong family history would have undergone whole colonic imaging based on current colorectal cancer management guidelines. The remaining seven patients with right-sided cancer would have been missed if FS were the only investigation used. Patients presenting on the 2ww with symptoms of a CIBH and/or RB can be adequately investigated with a FS with a 3% chance of missing a proximal cancer.

The 2-week wait referral system does not improve 5-year colorectal cancer survival.

AIM: The aim of this study was to compare 5-year survival rates in colorectal cancer (CRC) patients who underwent potentially curative surgery before and after the introduction of the 2-week wait (2WW) referral system. METHOD: Data were collected retrospectively from a prospectively maintained cancer database for CRC patients who underwent surgery in 1999 (pre-2WW group, n = 150) and 2002 (post-2WW group, n = 126). Patients who presented as an emergency, those who died within 30 days of surgery and those who presented with incurable CRC were excluded. We used the Kaplan-Meier method to plot survival curves and the log rank test to compare survival rates between the two groups. RESULTS: The 5-year survival rates in the pre-2WW and post-2WW groups did not differ significantly (71%vs 72%, respectively; P = 0.880). The number of CRC patients who presented via urgent pathways was higher in the post-2WW group than in the pre-2WW group (77%vs 38%, P < 0.001). Further, owing to this change in the referral pattern, the overall delay between referral and treatment was significantly lower in the post-2WW group than in the pre-2WW group (median 76 days vs 115, P = 0.009). CONCLUSION: The 2WW referral system for patients with symptoms of CRC does not translate into improved survival. However, more patients with symptomatic CRC are being referred via urgent pathways.

The reconstruction of invasion histories with genomic data in light of differing levels of anthropogenic transport.

Unravelling the history of range shifts is key for understanding past, current and future species distributions. Anthropogenic transport of species alters natural dispersal patterns and directly affects population connectivity. Studies have suggested that high levels of anthropogenic transport homogenize patterns of genetic differentiation and blur colonization pathways. However, empirical evidence of these effects remains elusive. We compared two range-shifting species (Microcosmus squamiger and Ciona robusta) to examine how anthropogenic transport affects our ability to reconstruct colonization pathways using genomic data. We first investigated shipping networks from the 18th century onwards, cross-referencing these with regions where the species have records to infer how each species has potentially been affected by different levels of anthropogenic transport. We then genotyped thousands of single-nucleotide polymorphisms from 280 M. squamiger and 190 C. robusta individuals collected across their extensive species' ranges and reconstructed colonization pathways. Differing levels of anthropogenic transport did not preclude the elucidation of population structure, though specific inferences of colonization pathways were difficult to discern in some of the considered scenario sets. We conclude that genomic data in combination with information of underlying introduction drivers provide key insights into the historic spread of range-shifting species. This article is part of the theme issue 'Species' ranges in the face of changing environments (part I)'.

Transcriptional regulation of the SCL locus: identification of an enhancer that targets the primitive erythroid lineage in vivo.

The stem cell leukemia (SCL) gene, also known as TAL-1, encodes a basic helix-loop-helix protein that is essential for the formation of all hematopoietic lineages, including primitive erythropoiesis. Appropriate transcriptional regulation is essential for the biological functions of SCL, and we have previously identified five distinct enhancers which target different subdomains of the normal SCL expression pattern. However, it is not known whether these SCL enhancers also regulate neighboring genes within the SCL locus, and the erythroid expression of SCL remains unexplained. Here, we have quantitated transcripts from SCL and neighboring genes in multiple hematopoietic cell types. Our results show striking coexpression of SCL and its immediate downstream neighbor, MAP17, suggesting that they share regulatory elements. A systematic survey of histone H3 and H4 acetylation throughout the SCL locus in different hematopoietic cell types identified several peaks of histone acetylation between SIL and MAP17, all of which corresponded to previously characterized SCL enhancers or to the MAP17 promoter. Downstream of MAP17 (and 40 kb downstream of SCL exon 1a), an additional peak of acetylation was identified in hematopoietic cells and was found to correlate with expression of SCL but not other neighboring genes. This +40 region is conserved in human-dog-mouse-rat sequence comparisons, functions as an erythroid cell-restricted enhancer in vitro, and directs beta-galactosidase expression to primitive, but not definitive, erythroblasts in transgenic mice. The SCL +40 enhancer provides a powerful tool for studying the molecular and cellular biology of the primitive erythroid lineage.

A DNA target-enrichment approach to detect mutations, copy number changes and immunoglobulin translocations in multiple myeloma.

Genomic lesions are not investigated during routine diagnostic workup for multiple myeloma (MM). Cytogenetic studies are performed to assess prognosis but with limited impact on therapeutic decisions. Recently, several recurrently mutated genes have been described, but their clinical value remains to be defined. Therefore, clinical-grade strategies to investigate the genomic landscape of myeloma samples are needed to integrate new and old prognostic markers. We developed a target-enrichment strategy followed by next-generation sequencing (NGS) to streamline simultaneous analysis of gene mutations, copy number changes and immunoglobulin heavy chain (IGH) translocations in MM in a high-throughput manner, and validated it in a panel of cell lines. We identified 548 likely oncogenic mutations in 182 genes. By integrating published data sets of NGS in MM, we retrieved a list of genes with significant relevance to myeloma and found that the mutational spectrum of primary samples and MM cell lines is partially overlapping. Gains and losses of chromosomes, chromosomal segments and gene loci were identified with accuracy comparable to conventional arrays, allowing identification of lesions with known prognostic significance. Furthermore, we identified IGH translocations with high positive and negative predictive value. Our approach could allow the identification of novel biomarkers with clinical relevance in myeloma.

In vivo assessment of release and metabolism of dopamine in the ventrolateral striatum of awake rats following administration of dopamine D1 and D2 receptor agonists and antagonists.

The ability of specific dopamine (DA) receptor agonists and antagonists to modify the release and metabolism of DA in the ventrolateral striatum of awake rats was assessed using in vivo microdialysis. The specific DA D2 receptor antagonist, raclopride (0.1, 0.5 and 2.0 mg/kg, i.p.), dose-dependently increased release of DA and levels of the metabolites DOPAC and HVA, while the D2 receptor agonist, quinpirole (0.03, 0.1 and 0.3 mg/kg), decreased levels of DA, DOPAC and HVA. The DA D1 receptor antagonist, SCH23390 [(R + (+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl- 1H-3-benzazepin-7-ol) (0.01, 0.05 and 0.25 mg/kg), produced an increase in DA, DOPAC and HVA but of a lesser magnitude than raclopride. The D1 agonist SKF38393 (1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol) (1.0, 3.0 and 10.0 mg/kg) failed to affect the release of metabolism of DA at any dose. These results support previous findings that activation of D2 receptors has greater control over in vivo DA function, than drugs specifically affecting D1 receptors.

The consequences of long-term antipsychotic drug administration on basal ganglia neuronal function in laboratory animals.

Antipsychotic drugs (APDs) have been widely utilized in the treatment of a variety of psychiatric disorders, most prevalently for schizophrenia. In addition to their desired therapeutic effects, repeated administration of APDs often produces various motor side effects. Experimental evidence has implicated alterations in the nuclei of the basal ganglia as the basis for the motor dysfunctions that may arise during APD treatment. Because APDs are invariably administered for extended periods of time, a great deal of research has focused on the effects of prolonged drug exposure. Animal models have been a particularly valuable tool for studying APD effects on basal ganglia function following several weeks (subchronic) to months or years (chronic) of administration. The present paper reviews the scope of studies that have assessed various aspects of basal ganglia function in laboratory animals treated with APDs for prolonged period of time. Possible mechanisms of action are reviewed regarding subchronic and chronic APD effects on basal ganglia function as well as directions for future research.

Sulphide-induced energy deficiency in colonic cells is prevented by glucose but not by butyrate.

BACKGROUND: In ulcerative colitis, hydrogen sulphide is postulated to impair colonocyte butyrate metabolism, leading to cellular energy deficiency and dysfunction. AIMS: To determine the effects of sulphide exposure on butyrate metabolism and adenosine triphosphate levels of HT29 colonic epithelial cancer cells, and to establish whether energy deficiency can be prevented by increased butyrate concentrations or the presence of glucose. METHODS: HT29 cells were maintained in medium containing 3 mM butyrate, 5 mM glucose, or both substrates. Oxidation rates were measured by 14CO2 release from 14C-labelled substrates. Cellular adenosine triphosphate was assayed using the luciferin/luciferase chemiluminescent method. The effects of sulphide (0-5 mM) on substrate oxidation and adenosine triphosphate levels and of increasing butyrate concentration (0-30 mM) with sulphide were observed. RESULTS: HT29 cells showed similar energy substrate usage to primary colonocyte cultures. Sulphide exposure inhibited butyrate oxidation and led to a reduction in cellular adenosine triphosphate. This fall was prevented by co-incubation with glucose, but not by increasing concentrations of butyrate. CONCLUSIONS: HT29 cells utilize butyrate as an energy substrate and represent a useful in vitro model of the effects of sulphide on colonocytes. Sulphide inhibits butyrate oxidation and leads to demonstrable energy deficiency, prevented by the presence of glucose but not by increased butyrate concentrations.

Neurotensin increases extracellular striatal dopamine levels in vivo.

This study employed intracranial microdialysis to assess the effects of neurotensin (NT) infusion on extracellular dopamine (DA) and DA metabolite concentrations in the rat striatum and nucleus accumbens, and the effects of NT on alterations in extracellular DA levels induced by cocaine and the DA D-2 receptor agonist, quinpirole. Direct NT infusion (.10, 1.0, 10.0 microM) did not significantly affect extracellular DA in the nucleus accumbens, but did produce a significant increase in the DA metabolite homovanillic acid (HVA). In contrast, direct NT infusion produced an increase in striatal DA levels, without altering DA metabolites. Neurotensin infusion (.10 microM) into the striatum significantly attenuated the peak DA increase induced by an intraperitoneal (IP) injection of a low dose (10.0 mg/kg) but not a high dose (30.0 mg/kg) of cocaine. Neurotensin infusion (.10 microM) did not affect the decrease in DA and its metabolites induced by an IP injection of a low dose of quinpirole (.03 mg/kg), but did alter the decrease in HVA induced by a high dose of quinpirole (.10 mg/kg). These results suggest that NT differentially affects in vivo DA release in the striatum and nucleus accumbens, and further strengthens the assertion that NT is an important modulator of dopaminergic function.

The neurotensin receptor antagonist SR 48692 decreases extracellular striatal GABA in rats.

Intracranial microdialysis was utilized to assess the effects of the novel neurotensin antagonist SR 48692 on extracellular gamma-amino-butyric acid (GABA) and glycine in the striatum. Subcutaneous injection of SR 48692 (0.2 mg/kg) significantly decreased extracellular striatal GABA levels, with peak decreases occurring 2-3 h post-injection. Injection of SR 48692 had no significant effect on glycine levels. These data suggest that endogenous neurotensin may modulate striatal GABA levels.

Altered Fos-like immunoreactivity in terminal regions of the mesotelencephalic dopamine system is associated with reappearance of tyrosine hydroxylase immunoreactivity at the sites of focal 6-hydroxydopamine lesions in the nucleus accumbens.

The present study was undertaken in order to determine whether unilateral 6-hydroxydopamine (6-OHDA) lesions in the nucleus accumbens (Acb) affect basal Fos-like immunoreactivity (-LI) in terminal regions of the mesotelencephalic dopamine system. It was hypothesized that dopamine depletion in the Acb would alter activation of mesotelencephalic dopamine neurons perhaps via the striatomesencephalic GABAergic pathway, and that this may be detected as altered basal Fos-LI in mesotelencephalic terminal regions. 6-OHDA treatment effectively depleted tyrosine hydroxylase (TH)-LI in well-circumscribed areas of the Acb at 14 days post-lesion, but at 25 days post-lesion all animals showed a reappearance of TH-LI staining in the lesioned region. When data from a number of mesotelencephalic terminals regions was pooled. Fos-LI cell density was higher in the sham and lesion 14-day groups and sham 25-day group than both the 25-day lesion group and untreated controls. The present study demonstrates that unilateral sham and 6-OHDA lesions in the Acb may have repercussions throughout the mesotelencephalic dopamine system. Further investigation is necessary to determine whether reappearance of TH-LI at the lesion site contributes to the return of Fos-LI to basal levels.

Chronic neuroleptic administration decreases extracellular GABA in the nucleus accumbens but not in the caudate-putamen of rats.

The extracellular levels of gamma-aminobutyric acid (GABA) in the caudate-putamen and the nucleus accumbens of rats following administration of haloperidol decanoate, fluphenazine decanoate, or vehicle for 8 months were assessed using intracranial microdialysis. Basal levels of extracellular GABA were significantly decreased in the nucleus accumbens of both neuroleptic-treated groups while levels of GABA in the caudate-putamen were not significantly different between groups. These results provide evidence for selective chronic neuroleptic-induced effects on in vivo GABA function in different terminal regions containing dopamine receptors.

Chronic haloperidol, but not clozapine, produces altered oral movements and increased extracellular glutamate in rats.

Rats administered chronic haloperidol or clozapine in their drinking water for 6 months were monitored for changes in oral movements using a computerized video analysis system. Haloperidol-treated animals exhibited late onset increases in small amplitude oral movements and an increase in the percentage of oral movements in the 1-2 Hz range, accompanied by a decrease in oral movements in the higher frequency range (> 6 Hz) as determined by fast fourier analysis. In contrast, clozapine-treated rats showed a decrease in medium-sized amplitude oral movements, but did not demonstrate significant changes in the distribution of oral movements across frequencies. Extracellular concentrations of gamma-aminobutyric acid (GABA) and glutamate in the ventrolateral striatum were then assessed by intracranial microdialysis during oral drug administration and 3 days after drug withdrawal. Extracellular GABA and glutamate levels were not significantly different between groups during drug administration. However, 3 days after drug withdrawal, there was a significant increase in glutamate in the haloperidol-treated rats. No changes were noted for glutamate levels in clozapine-treated rats or for GABA levels in either group following withdrawal. These results confirm the atypical profile of clozapine in an animal model of tardive dyskinesia and suggest that alterations in striatal glutamatergic function follow typical, but not atypical, antipsychotic drug administration.

Regional differences in chronic neuroleptic effects on extracellular dopamine activity.

The extracellular levels of dopamine (DA) and DA metabolites in the caudate-putamen (CPu) and the nucleus accumbens (NA) of rats following administration of haloperidol (HAL) decanoate and fluphenazine (FLU) decanoate for 8 months were assessed using intracranial microdialysis 1 month after final injection. Both HAL- and FLU-treated animals showed persisting plasma neuroleptic levels at time of sacrifice. Extracellular basal levels of homovanillic acid (HVA) in the CPu were significantly elevated in the FLU-treated animals, while basal levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in the CPu were significantly elevated in the HAL-treated animals. Basal levels of DA and the serotonin metabolite, 5-hydroxyindoleacetic acid (5HIAA) in the CPu were not significantly different between groups. No significant between-group differences were found for basal levels of any of the analytes in the NA. Neuroleptic-treated animals showed an enhanced response to direct infusion through the dialysis probe of amphetamine (1 microM) and nomifensine (10 microM) in the CPu but not the NA. These results suggest that chronic neuroleptic treatment produces enhanced extracellular DA activity in nigrostriatal, but not mesolimbic DA pathways.

Cholinergic modulation of oral activity in drug-naive and chronic haloperidol-treated rats.

The cholinergic agonists pilocarpine, physostigmine, oxotremorine, and arecoline were administered IP at various doses to rats. Oral activity was assessed in these animals with a computerized video analysis system that determined the number and form of jaw openings and closings (computer scored movelets "CSMs"). The different cholinergic drugs produced distinctive changes in the number of CSMs at various amplitudes and in the frequency distribution of CSMs as determined by fast fourier analysis. Rats treated for 28 weeks with haloperidol showed a previously described, late onset oral dyskinesia characterized by increases in small amplitude CSMs, decreases in CSM slope, increased energy at the 1-3 Hz range and decreased energy at the 5-7 Hz range. Administration of pilocarpine (1.0 mg/kg) reversed all of these effects, while the anticholinergic drug, scopolamine (0.05 mg/kg), had no effect. These results indicate that different cholinomimetics can uniquely alter oral activity in rats and that symptoms of late onset, neuroleptic-induced oral dyskinesia are modified by a cholinergic agonist.

The role of the colonic flora in maintaining a healthy large bowel mucosa.

This work explores the intricate relationships between bacterial products of fermentation, the short chain fatty acids and the effect that these have on the colonic epithelium and the immune system. It confirms that butyrate is a major energy source for the colonic epithelium and there may be a minor epithelial abnormality in the metabolism of butyrate in patients with ulcerative colitis. Immunological studies suggest that butyrate has an effect on lymphocyte activation and inhibits cell proliferation. Possibly, butyrate induces anergy in lymphocytes via an effect on the TCR receptor. This may represent a mechanism whereby colonic bacteria are able to regulate the host immune response. An abnormal response to butyrate may upset the homeostasis between the gut immune system and the colonising bacteria resulting in epithelial unrest and inflammation.