Species diversity and mycotoxin production by members of the Fusarium tricinctum species complex associated with Fusarium head blight of wheat and barley in Italy.

Fusarium head blight (FHB) is a global cereal disease caused by a complex of Fusarium species. In Europe, the main species responsible for FHB are F. graminearum, F. culmorum and F. poae. However, members of the F. tricinctum species complex (FTSC) have become increasingly important. FTSC fusaria can synthesize mycotoxins such as moniliformin (MON), enniatins (ENNs) and several other biologically active secondary metabolites that could compromise food quality. In this study, FTSC isolates primarily from Italian durum wheat and barley, together with individual strains from four non-graminaceous hosts, were collected to assess their genetic diversity and determine their potential to produce mycotoxins in vitro on rice cultures. A multilocus DNA sequence dataset (TEF1, RPB1 and RPB2) was constructed for 117 isolates from Italy and 6 from Iran to evaluate FTSC species diversity and their evolutionary relationships. Phylogenetic analyses revealed wide genetic diversity among Italian FTSC isolates. Among previously described FTSC species, F. avenaceum (FTSC 4) was the most common species in Italy (56/117 = 47.9%) while F. tricinctum (FTSC 3), and F. acuminatum (FTSC 2) accounted for 11.1% (13/117) and the 8.5% (10/117), respectively. The second most detected species was a new and unnamed Fusarium sp. (FTSC 12; 32/117 = 19%) resolved as the sister group of F. tricinctum. Collectively, these four phylospecies accounted for 111/117 = 94.9% of the Italian FTSC collection. However, we identified five other FTSC species at low frequencies, including F. iranicum (FTSC 6) and three newly discovered species (Fusarium spp. FTSC 13, 14, 15). Of the 59 FTSC isolates tested for mycotoxin production on rice cultures, 54 and 55 strains, respectively, were able to produce detectable levels of ENNs and MON. In addition, we confirmed that the ability to produce bioactive secondary metabolites such as chlamydosporol, acuminatopyrone, longiborneol, fungerin and butanolide is widespread across the FTSC.

Role of the XylA gene, encoding a cell wall degrading enzyme, during common wheat, durum wheat and barley colonization by Fusarium graminearum.

Fusarium graminearum is the main causal agent of fusarium head blight (FHB) of wheat and barley. This filamentous fungus is able to produce hydrolytic enzymes, such as xylanases, that cause cell wall degradation, permitting host colonization. This study investigated the role of the F. graminearum XylA (FGSG_10999) gene during infection, using a knockout mutant in strain CS3005. Assays were carried out on common wheat, durum wheat and barley to compare virulence of a XylA knockout to that of wild type strain. These assays were conducted on wheat and barley seedling roots, seedling stem bases and heads. Furthermore, additional in vitro experiments were conducted to investigate the role of XylA gene in the utilisation of D-xylose, the main component of cereals cell wall. In planta assays showed the importance of XylA gene for F. graminearum virulence towards its main hosts. A positive correlation between symptom incidence and fungal biomass development was also observed for both the wild type and the knockout strains. Finally, gene expression studies performed in a liquid medium enriched with D-xylose, a known xylanase inducer in other fungi, showed that the absence of the gene in the FGSG_10999 locus was not compensated by two other F. graminearum xylanase encoding genes analysed (loci FGSG_06445 and FGSG_11478).

Causal agents of Fusarium head blight of durum wheat (Triticum durum Desf.) in central Italy and their in vitro biosynthesis of secondary metabolites.

Durum wheat samples harvested in central Italy (Umbria) were analyzed to: evaluate the occurrence of the fungal community in the grains, molecularly identify the Fusarium spp. which are part of the Fusarium head blight (FHB) complex and characterize the in vitro secondary metabolite profiles of a subset of Fusarium strains. The Fusarium genus was one of the main components of the durum wheat fungal community. The FHB complex was composed of eight species: Fusarium avenaceum (61%), F. graminearum (22%), F. poae (9%), F. culmorum (4%), F. proliferatum (2%), F. sporotrichioides (1%), F. sambucinum (0.5%) and F. langsethiae (0.5%). F. graminearum population was mainly composed of the 15-acetyldeoxynivalenol chemotype, while, F. culmorum population was composed of the 3-acetyldeoxynivalenol chemotype. In vitro characterization of secondary metabolite biosynthesis was conducted for a wide spectrum of substances, showing the mycotoxigenic potential of the species complex. F. avenaceum strains were characterized by high enniantin and moniliformin production. F. graminearum strains were in prevalence deoxynivalenol producers. F. poae strains were characterized by a high biosynthesis of beauvericin like the F. sporotrichioides strain which was also found to be a high T-2/HT-2 toxins producer. Production of aurofusarin, butenolide, gibepyrone D, fusarin C, apicidin was also reported for the analyzed strains.

Biosynthesis of beauvericin and enniatins in vitro by wheat Fusarium species and natural grain contamination in an area of central Italy.

Contamination of wheat grain by beauvericin (BEA) and enniatins (ENs) is a global emerging mycotoxicological food problem. In this study, strains of Fusarium avenaceum (FA), Fusarium poae (FP), Fusarium equiseti and Fusarium sporotrichioides, all potential BEA and EN producers, isolated from 162 grain samples of durum and soft wheat harvested in 2009 and 2010 collected in an area of central Italy, were preliminarily screened for the presence of the esyn1 gene, encoding the multifunctional enzyme enniatin-synthetase for the detection of potential hexadepsipeptide-producing isolates. All positive isolates were tested for their ability to biosynthesize BEA and ENs in vitro. In addition, all wheat samples were investigated for the natural presence of BEA and ENs (ENA, ENA1, ENB, ENB1). All FA and FP strains resulted to be positive for the presence of the esyn1 gene. All FA strains showed the ability to biosynthesize ENs in vitro but not BEA. Conversely, all FP strains resulted to be BEA producers and some of them co-biosynthesized ENs. A remarkable presence of "emerging" mycotoxins was found in the grains, particularly ENs. Co-contamination by BEA and ENs also occurred. This study gives an important contribution to assess the risk posed by mycotoxigenic fungi and their mycotoxins in food.

Dynamical age differences among coeval star clusters as revealed by blue stragglers.

Globular star clusters that formed at the same cosmic time may have evolved rather differently from the dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend progressively to segregate stars more massive than the average towards the cluster centre. Therefore clusters with the same chronological age may have reached quite different stages of their dynamical history (that is, they may have different 'dynamical ages'). Blue straggler stars have masses greater than those at the turn-off point on the main sequence and therefore must be the result of either a collision or a mass-transfer event. Because they are among the most massive and luminous objects in old clusters, they can be used as test particles with which to probe dynamical evolution. Here we report that globular clusters can be grouped into a few distinct families on the basis of the radial distribution of blue stragglers. This grouping corresponds well to an effective ranking of the dynamical stage reached by stellar systems, thereby permitting a direct measure of the cluster dynamical age purely from observed properties.

Two distinct sequences of blue straggler stars in the globular cluster M 30.

Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers resulting from direct collisions between two stars. Recently the binary explanation was claimed to be dominant. Here we report that there are two distinct parallel sequences of blue stragglers in M 30. This globular cluster is thought to have undergone 'core collapse', during which both the collision rate and the mass transfer activity in binary systems would have been enhanced. We suggest that the two observed sequences are a consequence of cluster core collapse, with the bluer population arising from direct stellar collisions and the redder one arising from the evolution of close binaries that are probably still experiencing an active phase of mass transfer.

The cluster Terzan 5 as a remnant of a primordial building block of the Galactic bulge.

Globular star clusters are compact and massive stellar systems old enough to have witnessed the entire history of our Galaxy, the Milky Way. Although recent results suggest that their formation may have been more complex than previously thought, they still are the best approximation to a stellar population formed over a relatively short timescale (less than 1 Gyr) and with virtually no dispersion in the iron content. Indeed, only one cluster-like system (omega Centauri) in the Galactic halo is known to have multiple stellar populations with a significant spread in iron abundance and age. Similar findings in the Galactic bulge have been hampered by the obscuration arising from thick and varying layers of interstellar dust. Here we report that Terzan 5, a globular-cluster-like system in the Galactic bulge, has two stellar populations with different iron contents and ages. Terzan 5 could be the surviving remnant of one of the primordial building blocks that are thought to merge and form galaxy bulges.

A New Race, 704, of Plasmopara helianthi Pathogen of Sunflower Downy Mildew in Italy.

The recent changes of the European Common Agricultural Policy and the market needs of oleaginous crops for energy purposes caused a renewed increase of sunflower (Helianthus annuus L.) cultivation in Italy. During 2006, surveys on approximately 92 ha of Umbrian (central Italy) sunflower fields were carried out for monitoring distribution and race variability of the pathogen. Twelve fields planted with commercial hybrids were surveyed. Downy mildew was only observed in five fields, with 2 to 3% of disease incidence. Systemic mildewed plants showed stunting, leaf chlorosis, and sporulation on the underside of leaf surface. Pathogen inocula were directly recovered from infected leaves by brushing the fungal structures or after infected leaves were incubated in a humid chamber at 18 to 20°C in the dark for 24 to 48 h. After increasing initial inocula on the suscpetible cv. Ala, race identification of four isolates was determined by the reaction of three standard sets of nine differential sunflower lines using a triplet code (3). Thirty to forty pregerminated seeds for each differential line (three replicates per line) were inoculated by the whole-seedling immersion technique (1). After 12 days, plants were maintained at 20°C and 100% relative humidity for 24 to 48 h to enhance pathogen sporulation and evaluate for susceptible (sporulation on cotyledons and/or first true leaves) or resistance (absence of sporulation or weak sporulation only on cotyledons) reactions. Inoculation tests were performed twice. The isolates were also evaluated for their sensitivity to metalaxyl-M (Apron XL 31.8%) used at the Italian registered rate (1.05 g of a.i. per kg of seed). Treated and untreated seeds of cv. Ala (50 seeds per pot with three replicates) were sown into pots filled with a sterilized sandy-loam mixture (1:1, vol/vol). Five days after sowing, soil drench inoculation was performed by spreading over the pots (80 ml per pot) a zoosporangia suspension (1 to 2 × 104 zoosporangia per ml) of each isolate. Disease incidence (DI) was determined by counting the number of uninfected and infected plants (sporulation on cotyledons and/or true leaves). Hypocotyls of plants that seemed uninfected were cut into sections (2 to 3 cm long) and placed in a humid chamber to allow pathogen sporulation. The experiments were performed twice. Three isolates were characterized as race 700 and one as a mixture of races 700 and 704. Race 700 is more widespread in Italy, whereas race 704 was reported in France in 2002 (2). All Plasmopara helianthi isolates produced 84 to 89% infection on plants from untreated seeds, whereas DI from fungicide treated seeds was significantly lower (8 to 17%). To our knowledge, this is the first report of race 704 in Italy. All field isolates were also metalaxyl-M sensitive as already reported in other European countries (4). References: (1) T. J. Gulya et al. Helia 14:11, 1991. (2) E. Mestries. Oleoscope 83:13, 2005. (3) M. L. Molinero et al. Plant Dis. 86:736, 2002. (4) M. L. Molinero et al. Plant Dis. 87:749, 2003.

Use of the Given Patency System for the screening of patients at high risk for capsule retention.

BACKGROUND: Capsule enteroscopy is a non-invasive diagnostic tool for the study of the small bowel. Due to the risk of capsule retention, capsule enteroscopy is contraindicated in patients with suspected small bowel strictures. The Given Patency Capsule is a disintegration time-controlled capsule developed to identify patients with strictures that may cause capsule enteroscopy retention. The presence of the patency capsule within the patient's body can be detected by a radio-frequency scanner. AIM OF THE STUDY: To evaluate safety and usefulness of the patency capsule in preventing capsule retention in patients at high risk. PATIENTS AND METHODS: Thirty-two patients were studied. Indications for patency capsule were: (A) Crohn's disease (18), (B) previous intestinal surgery (7), (C) previous obstruction (1), A+B (3), A+C (1), B+C (2). Patients were evaluated with the scanner at 72 h from ingestion. RESULTS: At 72 h, 24 patients had already excreted the intact capsule in the stool. Of these, two experienced abdominal pain during capsule passage. In the other eight patients, the scanner detected the presence of the patency capsule. Four of them excreted the capsule intact in the stool after 72-96 h, the remaining four never found the capsule in the stool. The 26 patients who excreted the patency capsule intact without experiencing abdominal pain were deemed eligible for the capsule enteroscopy procedure, which was performed uneventfully in the 25 who agreed to undergo the examination. CONCLUSIONS: The patency capsule is useful to identify, among patients at high risk, those who can be submitted to capsule enteroscopy without risks of capsule retention.

Sensitivity and specificity of the suspected blood identification system in video capsule enteroscopy.

BACKGROUND AND STUDY AIMS: Capsule enteroscopy has become a standard tool for the evaluation of obscure gastrointestinal bleeding. Reviewing the video recordings of capsule examinations is time-consuming and requires prolonged attention. Recently, software that can recognize the frames containing "red spots", the Suspected Blood Identification system (SBIS), has been developed with the aim of assisting in the analysis of video recordings. We assessed the sensitivity and specificity of the SBIS in patients undergoing capsule enteroscopy. PATIENTS AND METHODS: 100 consecutive patients underwent capsule enteroscopy at our tertiary referral center, for the following indications: obscure gastrointestinal bleeding (75 patients), metastatic carcinoid (7 patients) known or suspected Crohn's disease (5 patients), miscellaneous (13 patients). Capsule endoscopy was carried out by the standard method. Four gastroenterologists, experienced in capsule endoscopy, reviewed the recordings. RESULTS: Small-bowel visualization was obtained in 95 cases. The physicians identified 209 "red spots", 54 of which (25.8%) were also identified by the SBIS. The overall sensitivity, specificity, and positive and negative predictive values of the SBIS, calculated on the number of true-positive, true-negative, false-positive and false-negative results, were 40.9%, 70.7%, 69.2% and 42.6%, respectively. Sensitivity was higher for the identification of red blood (60.9%) than for nonbleeding "red" lesions such as arteriovenous malformations (25.8%). CONCLUSIONS: The SBIS has low sensitivity and specificity. It can be used as a complementary and rapid screening tool, but complete review of the recordings is still necessary.

Capsule enteroscopy in small bowel transplantation.

BACKGROUND: Enteroscopy plays a key role in the post-operative monitoring of patients with small bowel transplantation for the early detection of post-transplant complications and for the assessment of the graft's integrity. Routine surveillance enteroscopies (trans-stomal terminal ileoscopy or jejunoscopy) are invasive, may be unsafe in frail patients, and only allow incomplete exploration of the transplanted graft, which may be unsatisfactory. since the distribution of the lesions is often patchy or segmental. AIMS. To evaluate the potential of capsule enteroscopy, a new, minimally invasive technique which allows complete exploration of the small bowel. in small bowel transplant recipients. METHODS: Five small bowel transplanted patients underwent capsule enteroscopy with the GIVEN endoscopy system. The results of capsule enteroscopy were compared with those of trans-stomal ileoscopy. RESULTS: Capsule enteroscopy was better tolerated than ileoscopy and good quality images of the small bowel were obtained in four patients. The terminal ileum was normal both on ileoscopy and capsule enteroscopy. Mucosal changes in segments not reached by ileoscopy were detected by capsule enteroscopy in three of four patients. CONCLUSIONS: Capsule enteroscopy is better tolerated than ileoscopy, allows complete exploration of the transplanted graft and can detect mucosal changes in segments not reached by ileoscopy.

Unsuspected ileal stenosis causing obscure GI bleeding in patients with previous abdominal surgery--diagnosis by capsule endoscopy: a report of two cases.

Peri-anastomotic ulcerations may occur in patients with previous abdominal surgery. They may present only with obscure GI bleeding. We report two cases in whom capsule endoscopy identified postsurgical stenoses with ulcers as the cause of obscure GI bleeding. Case 1. A 57-year-old male operated on in 1970 for a post-traumatic diaphragm hernia followed by displacement of the caecum in the upper left abdominal quadrant. Case 2. A 32-year-old female with a salpingectomy for tuberculosis (1978) followed by segmental ileal resection for intestinal obstruction. Both patients had undergone extensive work-up including bidirectional endoscopies and enteroclysis with negative results. Capsule endoscopy with the GIVEN diagnostic system was done. Ileal stenoses with mucosal ulcers in dilated prestenotic loops were observed in both cases. The capsule was retained at the stenosis site, requiring ileal resection and anastomosis. Pathology reports showed mucosal ulcers. In case 2, tuberculosis was ruled out by tissue and faecal polymerase chain reaction and culture. Ileal stenoses with prestenotic ulcerations causing GI bleeding may occur in patients with previous abdominal surgery. Capsule endoscopy may clarify the diagnosis and shorten the diagnostic work-up. However, these patients should be warned that capsule retention requiring surgery might occur.

High prevalence of Helicobacter pylori infection in patients with colonic adenomas and carcinomas.

In some uncontrolled studies, a high prevalence of Helicobacter pylori infection unexpectedly has been found in patients with colorectal cancer. The purpose of the study was to investigate the prevalence of H. pylori infection in patients with colonic polyps or cancer. We reviewed 50 consecutive patients with either colonic adenomas or cancer who entered a preliminary case-control study. For each patient, 2 age- and gender-matched control subjects were selected (72 males; mean age, 63.1 years). A further 44 consecutive patients (30 with polyps and 14 with cancer) subsequently were enrolled. The H. pylori prevalence in patients with either polyps or cancer was compared with that in control subjects. Anti-H. pylori immunoglobulin G antibodies were assayed by an immunoenzymatic method. The prevalence of H. pylori antibodies was 49 (49%) of 100 in control subjects, 40 (71.4%) of 56 in patients with polyps (p < 0.006 vs. control subjects), and 21 (55%) of 38 in patients with cancer (not significant). Among patients with colorectal cancer, H. pylori prevalence was 9 (69.2%) of 13 for patients evaluated at the time of diagnosis and 12 (48%) of 25 for patients evaluated 1 to 9 years after surgery. We conclude that colonic neoplastic lesions, especially adenomas, are associated with an increased prevalence of H. pylori infection. The mechanisms underlying this association need to be elucidated.