Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager.

Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.

Affinity-selected heparan sulfate for bone repair.

Bone morphogenetic protein (BMP)-2 is a potent bone healing compound produced at sites of bone trauma. Here we present a therapeutic strategy to harness the activity of endogenously produced BMP-2 by delivery of an affinity-matched heparan sulfate (HS) glycos aminoglycan biomaterial that increases the bioavailability, bioactivity and half-life of this growth factor. We have developed a robust, cost effective, peptide-based affinity platform to isolate a unique BMP-2 binding HS variant from commercially available preparations of HS, so removing the manufacturing bottleneck for their translation into the clinic. This affinity-matched HS enhanced BMP-2-induced osteogenesis through improved BMP-2 kinetics and receptor modulation, prolonged pSMAD signaling and reduced interactions with its antagonist noggin. When co-delivered with a collagen implant, the HS was as potent as exogenous BMP-2 for the healing of critical-sized bone defects in rabbits. This affinity platform can be readily tuned to isolate HS variants targeted ata range of clinically-relevant growth and adhesive factors.

Efficacy of dose regimen and observation of herd immunity from a vaccine against Escherichia coli O157:H7 for feedlot cattle.

A clinical trial was conducted to test the effect of a vaccine product containing type III secreted proteins of Escherichia coli O157:H7 on the probability that feedlot steers shed E. coli O157:H7 in feces. Six hundred eight same-source steers were utilized. Of these, 480 steers were assigned randomly to 60 pens (eight head per pen) and to one of four vaccination treatments (120 cattle per treatment, two head per treatment per pen). The four treatments were (i) no vaccination; (ii) one dose, vaccinated once at reimplant (day 42); (iii) two doses, vaccinated on arrival (day 0) and again at reimplant (day 42); and (iv) three doses, vaccinated on arrival (day 0), on day 21, and again at reimplant (day 42). The remaining 128 steers were assigned randomly to 12 pens within the same feedlot to serve as unvaccinated external controls. The probability of detecting E. coli O157:H7 among cattle receiving different doses of vaccine was compared with that of unvaccinated external control cattle, accounting for clustering by repeated measures, block, and pen and fixed effects of vaccine, corn product, and test period. Vaccine efficacy of receiving one, two, and three doses of vaccine was 68, 66, and 73%, respectively, compared with cattle in pens not receiving vaccine. Cattle receiving three doses of vaccine were significantly less likely to shed E. coli O157:H7 than unvaccinated cattle within the same pen. Unvaccinated cattle housed with vaccinated cattle were 59% less likely to shed E. coli O157:H7 than cattle in pens not receiving vaccine, likely because they benefited from herd immunity. This study supports the hypothesis that vaccination with this vaccine product effectively reduces the probability for cattle to shed E. coli O157:H7. There was no indication that the vaccine affected performance or carcass quality. In addition, we found that vaccinating a majority of cattle within a pen offered a significant protective effect (herd immunity) to unvaccinated cattle within the same pen.

Effect of a vaccine product containing type III secreted proteins on the probability of Escherichia coli O157:H7 fecal shedding and mucosal colonization in feedlot cattle.

Preharvest intervention strategies to reduce Escherichia coli O157:H7 in cattle have been sought as a means to reduce human foodborne illness. A blinded clinical trial was conducted to test the effect of a vaccine product on the probability that feedlot steers, under conditions of natural exposure, shed E. coli O157:H7 in feces, are colonized by this organism in the terminal rectum, or develop a humoral response to the respective antigens. Steers (n = 288) were assigned randomly to 36 pens (eight head per pen), and pens were randomized to vaccination treatment in a balanced fashion within six dietary treatments of an unrelated nutrition study. Treatments included vaccination or placebo (three doses at 3-week intervals). Fecal samples for culture (n = 1,410) were collected from the rectum of each steer on pretreatment day 0 and posttreatment days 14, 28, 42, and 56. Terminal rectum mucosal (TRM) cells were aseptically collected for culture at harvest (day 57 posttreatment) by scraping the mucosa 3.0 to 5.5 cm proximal to the rectoanal junction. E. coli O157:H7 was isolated and identified with selective enrichment, immunomagnetic separation, and PCR confirmation. Vaccinated cattle were 98.3% less likely to be colonized by E. coli O157:H7 in TRM cells (odds ratio = 0.014, P < 0.0001). Diet was also associated with the probability of cattle being colonized (P = 0.04). Vaccinated cattle demonstrated significant humoral responses to Tir and O157 lipopolysaccharide. These results provide evidence that this vaccine product reduces E. coli O157:H7 colonization of the terminal rectum of feedlot beef cattle under conditions of natural exposure, a first step in its evaluation as an effective intervention for food and environmental safety.

Effect of Lactobacillus acidophilus strain NP51 on Escherichia coil O157:H7 fecal shedding and finishing performance in beef feedlot cattle.

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli O157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP51 supplementation or no supplementation (control). NP51 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of 10(9) CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli O157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli O157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli O157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP51-treated steers to shed E. coli O157:H7 over the test periods was 13 and 21%, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli O157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli O157:H7 fecal shedding in feedlot cattle.

Use of rope devices to describe and explain the feedlot ecology of Escherichia coli O157:H7 by time and place.

Escherichia coli O157:H7 is an important pathogen of humans, and cattle populations serve as an important reservoir for human exposure. The organism is ubiquitous to feedlot cattle populations, although the nature of its occurrence is quite dynamic. Why E. coli O157:H7 varies by time and place in fed cattle is poorly understood. This study was designed to describe and explain the occurrence of E. coli O157:H7 by pen-level factors of time and place. From each pen, we cultured seven ropes placed within pens for cattle to rub and chew (ROPES), in order to classify the pens as high or low prevalence in longitudinal studies conducted during the summer and winter feeding periods of 2 full years. We observed differences in occurrence of ROPES-positive pens by season, weeks within season, and feedyard. ROPES-positive pens clustered temporally. Factors associated with ROPES-positive pen-weeks during both the summer and winter feeding periods were feedyard, prior 7-day mean air temperature, recovery of E. coli O157:H7 from the composite fecal sample, and recovery of E. coli O157:H7 from the water tank. Pens of summer-fed cattle were less likely to be ROPES-positive for E. coli O157:H7 if the ROPES were positive for Salmonella spp. The condition of the pen surface was associated with the likelihood for winter-fed pens of cattle to be ROPES-positive. We were able to monitor these pens of cattle using ROPES at minimal cost and without disturbing individual cattle. These observations improve our understanding of the ecology of E. coli O157:H7 in fed cattle, and also illustrate the importance of designing and analyzing observational studies and clinical trials to account for time- and place-dependent variables that affect the probability of detecting E. coli O157:H7.

Use of rope devices to describe and explain the feedlot ecology of Salmonella by time and place.

Salmonella spp. are important zoonotic pathogens, and cattle can serve as an important source of this organism for human exposure through food. This study was designed to describe and explain the occurrence of Salmonella spp. by pen-level factors of time and place using a pen-level test-method previously validated for E. coli O157:H7. From each pen, we cultured seven ropes placed within the pen for cattle to rub and chew (ROPES), in order to classify the pens as ROPES-positive or ROPES-negative each week in longitudinal studies conducted during the summer and winter feeding periods of 2 full years. We observed differences in occurrence of ROPES-positive pens by week within each season such that, at times, a high proportion of pens were of the same ROPES-status even though feedyards were separated by 50-200 km. Factors associated with ROPES-positive pen-weeks during both the summer and winter feeding periods were the condition of the pen surface and recovery of Salmonella spp. from the water tank. The probability for pens of summer-fed cattle to be ROPES-positive for Salmonella spp. increased as the number of cattle in the pen increased and decreased when the pen was ROPES-positive for E. coli O157:H7. Pens of winter-fed cattle differed by feedyard in the probability of their being ROPES-positive for Salmonella spp. We were able to monitor these pens using ROPES at minimal expense, without disturbing individual cattle, and observe important time and place relationships of Salmonella spp. in fed cattle. These observations illustrate the importance of accounting for time- and place-dependent variables that affect the probability of detecting Salmonella spp. when designing and analyzing observational studies and clinical trials.

A diagnostic strategy to determine the Shiga toxin-producing Escherichia coli O157 status of pens of feedlot cattle.

Although cattle are reservoirs, no validated method exists to monitor Shiga toxin-producing Escherichia coli O157 (STEC O157) on farms. In 29 Midwestern United States feedlot pens we compared culturing faeces from the individual cattle to: (1) culturing rope devices that cattle rub or chew; and (2) culturing a composite of faecal pats. Eighty-six per cent (68-96%) of pens were classified correctly using rope devices to detect pens with at least 16% of the cattle shedding STEC O157 [sensitivity=82% (57-96%); specificity=92% (62-100%)]. Ninety per cent of pens (73-98%) were classified correctly using composite faeces to detect pens with at least 37% of the cattle shedding STEC O157 [sensitivity=86% (42-100%); specificity=91% (71-99%)]. Ranking pens into three risk levels based on parallel interpretation of the pen-test results correlated (Spearman's r=0.76, P<0.0001) with the pen's prevalence. This strategy could identify pens of cattle posing a higher risk to food safety.

Incidence, duration, and prevalence of Escherichia coli O157:H7 fecal shedding by feedlot cattle during the finishing period.

The objective was to describe variability in prevalence, incidence, and duration of fecal shedding of naturally occurring E. coli O157:H7 by a group of feedlot cattle over time. One hundred steers, randomly assigned to 10 pens, were fed a high-concentrate finishing diet for 136 days (19 weeks). Rectal feces from each animal were tested for E. coli O157:H7 every week for 19 weeks. E. coli O157:H7 was recovered from each animal that completed the study and was detected from at least one animal every week. Average pen prevalence of cattle shedding E. coli O157:H7 varied significantly over time (P < 0.0001) and across pens (P < 0.0001), ranging from 1 to 80%. Pairwise comparisons of mean pen prevalence of E. coli O157:H7 between weeks and estimation of the predicted probability of an incident case of E. coli O157:H7 over time allowed the definition of three distinct phases--namely, the preepidemic, epidemic, and postepidemic periods. Average pen prevalence varied significantly over time (P < 0.01) and across pens (P < 0.001) for all time periods. The odds of an incident case were significantly greater during epidemic and postepidemic periods relative to the preepidemic period (P = 0.0002 and P = 0.03, respectively). Duration of infection was significantly longer for first or second infections that began during epidemic or postepidemic periods relative to the preepidemic period (P < 0.001). Both incidence and duration of shedding peaked during the epidemic period. Pen-level prevalence of cattle shedding E. coli O157:H7 was affected by both incidence and duration of shedding and could be explained by time- or pen-dependent risk factors, or both.

Effects of virion host shut-off activity of bovine herpesvirus 1 on MHC class I expression.

Previously, we have shown that bovine herpesvirus 1 (BHV-1) down-regulates the expression of major histocompatibility complex class I molecules by interfering with transport of peptides by the transporter associated with antigen processing (TAP). Further studies revealed that BHV-1 down-regulates the expression of mRNA for class I molecules and other cellular proteins. To further elucidate the mechanisms of down-regulation of class I molecules, a virion host shut-off (vhs) deletion mutant was generated. The mutant, like the wildtype (wt) virus, interfered with transport of peptides by the TAP, and down-regulated cell surface expression of class I molecules. However, unlike the wt virus, the mutant did not impair the synthesis of class I molecules. These results indicate that down-regulation of class I molecules by BHV-1 is mediated by vhs activity of the virus, as well as mechanisms specifically directed at the class I pathway. Absence of vhs activity should result in decreased pathogenicity and enhanced immunogenicity of BHV-1 vhs deletion mutant, making it a better vaccine candidate.

Hodgsonox, a new class of sesquiterpene from the liverwort Lepidolaena hodgsoniae. Isolation directed by insecticidal activity.

Hodgsonox (1), a new insecticidal sesquiterpene, has been isolated from the New Zealand liverwort Lepidolaena hodgsoniae. The structure was elucidated on the basis of 2D NMR analysis of 1 and a synthetic epoxide derivative (2). Hodgsonox represents a new class of sesquiterpene with a cyclopenta[5,1-c]pyran ring system fused to an oxirane ring. The combination of a mono- and a 1,1 disubstituted double bond flanking the oxygenated carbon of a the pyran ring is a unique structural feature. Hodgsonox is toxic to larvae of the blowfly Lucilia cuprina.

Atranones A-G, from the toxigenic mold Stachybotrys chartarum.

Atranones A-G have been isolated from the toxigenic fungus Stachybotrys chartarum. These compounds contain several unusual features including an enol-lactone as part of a 3,7-dioxabicyclo[3.3.0]octane-2-one ring system fused to an 11-membered ring. Two new dolabellane diterpenes, related in structure to the atranones were also isolated, which suggests a diterpenoid origin for the C24 atranones.

A vhs-like activity of bovine herpesvirus-1.

Bovine herpesvirus 1 (BHV-1) is a major pathogen of cattle, causing significant disease including immunosuppression in infected animals. In vitro, the surface expression of major histocompatibility complex (MHC) class I molecules, crucial for an appropriate anti-viral immune response of the host, is down-regulated by BHV-1 infection. Northern blot analyses revealed that the mRNAs for MHC class I and class II molecules were significantly down-regulated in BHV-1 infected cells, starting as early as 2 h after infection. Furthermore, mRNA expression of the two house keeping genes actin and glyceraldehyde-6-phosphate dehydrogenase (GAPDH) was also repressed after infection. This BHV-1 induced effect on cellular metabolism resembled the virion host shutoff (vhs) activity of herpes simplex virus (HSV). Similar to the HSV vhs activity, the putative BHV-1 vhs activity was not abrogated in cells infected in the presence of actinomycin D (ActD) which suggested that no viral gene expression is required for the vhs function and the putative vhs protein is associated with the virion. Sequence comparison indicated a BHV-1 open reading frame having a 60% similarity to the HSV vhs sequence. This putative BHV-1 open reading frame contained the four conserved regions of the alphaherpesvirus vhs protein. Since an HSV vhs-mutant exhibited less virulence and good immunogenicity, we suggest that a BHV-1 vhs- mutant may hold promising potential as a candidate vaccine.

Evaluation of Stachybotrys chartarum in the house of an infant with pulmonary hemorrhage: quantitative assessment before, during, and after remediation.

Stachybotrys chartarum is an indoor mold that has been associated with pulmonary hemorrhage cases in the Cleveland, Ohio, area. This study applied two new quantitative measurements to air samples from a home in which an infant developed PH. Quantitative polymerase chain reaction and a protein synthesis inhibition assay were used to determine the level of S. chartarum spores and their toxicity in air samples taken before, during, and after a remediation program was implemented to remove the fungus. Initial spore concentrations were between 0.1 and 9.3 spores/m3 of air, and the toxicity of air particulates was correspondingly low. However, the dust in the house contained between 0.4 and 2.1 x 10(3) spores/mg (as determined by hemocytometer counts). The remediation program removed all contaminated wallboard, paneling, and carpeting in the water-damaged areas of the home. In addition, a sodium hypochlorite solution was used to spray all surfaces during remediation. Although spore counts and toxicity were high during remediation, air samples taken postremediation showed no detectable levels of S. chartarum or related toxicity. Nine isolates of S. chartarum obtained from the home were analyzed for spore toxicity, hemolytic activity, and random amplified polymorphic DNA banding patterns. None of the isolates produced highly toxic spores (>90 microg T2 toxin equivalents per gram wet weight spores) after growth for 10 and 30 days on wet wallboard, but three isolates were hemolytic consistently. DNA banding patterns suggested that at least one of these isolates was related to isolates from homes of infants with previously investigated cases.

An early pseudorabies virus protein down-regulates porcine MHC class I expression by inhibition of transporter associated with antigen processing (TAP).

The objectives of this study were to identify the mechanism(s) of pseudorabies virus (PrV)-induced down-regulation of porcine class I molecules and the viral protein(s) responsible for the effect. The ability of PrV to interfere with the peptide transport activity of TAP was determined by an in vitro transport assay. In this assay, porcine kidney (PK-15) cells were permeabilized with streptolysin-O and incubated with a library of 125I-labeled peptides having consensus motifs for glycosylation in the endoplasmic reticulum (ER). The efficiency of transport of peptides from the cytosol into the ER was determined by adsorbing the ER-glycosylated peptides onto Con A-coupled Sepharose beads. Dose-dependent inhibition of TAP activity was observed in PrV-infected PK-15 cells. This inhibition, which occurred as early as 2 h postinfection (h.p.i.), reached the maximum level by 6 h.p.i., indicating that TAP inhibition is one of the mechanisms by which PrV down-regulates porcine class I molecules. Infection of cells with PrV in the presence of metabolic inhibitors revealed that cycloheximide a protein synthesis inhibitor, but not phosphonoacetic acid a herpesvirus DNA synthesis inhibitor, could restore the cell surface expression of class I molecules, indicating that late proteins are not responsible for the down-regulation. Infection in the presence of cycloheximide followed by actinomycin-D, which results in accumulation of the immediate-early protein, failed to down-regulate class I, indicating that one or more early proteins are responsible for the down-regulation of class I molecules.

Stachybotrys: An unusual mold associated with water-damaged buildings.

Chemical analyses of extracts of cultures ofS. chartarum show that this fungus has two chemotypes: producers of the potent cytotoxic macrocyclic trichothecenes (e. g. satratoxins) and those that produce the diterpenoid atranones and the simple trichothecenes, trichodermol and trichodermin. All isolates ofS. chartarum produce the immunosuppressant spirocyclic drimanes.

Memnobotrins and memnoconols: novel metabolites from Memnoniella echinata.

Four novel metabolites have been isolated from a rice culture of Memnoniella echinata (JS6308) by solvent extraction and radial silica chromatography. The structures were elucidated by spectroscopic techniques, and the absolute stereochemistry of memnobotrin A determined by X-ray crystallography.

Study of toxin production by isolates of Stachybotrys chartarum and Memnoniella echinata isolated during a study of pulmonary hemosiderosis in infants.

A cluster of cases of pulmonary hemosiderosis among infants was reported in Cleveland, Ohio, during 1993 and 1994. These unusual cases appeared only in infants ranging in age from 1 to 8 months and were characterized by pulmonary hemorrhage, which caused the babies to cough up blood. A case-control study identified major home water damage (from plumbing leaks, roof leaks, or flooding) as a risk factor for development of pulmonary hemorrhage in these infants. Because of an interest in the possibility that trichothecene mycotoxins might be involved in this illness, a number of isolates of Stachybotrys chartarum were grown in the laboratory on rice, and extracts were prepared and analyzed both for cytotoxicity and for specific toxins. Two isolates of Memnoniella echinata, a fungus closely related to S. chartarum, were also included in these studies. S. chartarum isolates collected from the homes were shown to produce a number of highly toxic compounds, and the profiles of toxic compounds from M. echinata were similar; the most notable difference was the fact that the principal metabolites produced by M. echinata were griseofulvins.