Evaluation of irradiation and Termin-8® addition to spray-dried animal plasma, base mix and/or whole diet on growth performance of nursery pigs

Two studies were conducted to evaluate the effects of irradiation of spray-dried animal plasma and Termin-8 treatment to spray-dried animal plasma, base mix (specialty protein products, milk products, ground oat groats, soy flour, flow agent, vitamins, and minerals), or whole diet on nursery pig performance. Overall (d 0 to 14) in Exp. 1, pigs fed diets containing irradiated plasma had increased ADG and pigs fed Termin-8® treated plasma had increased ADG and ADFI compared to pigs fed diets with regular plasma or whole diets (containing either regular or irradiated plasma) treated with Termin-8. No differences in F/G were observed among treatments. In Exp. 2, pigs fed diets that contained either animal plasma or base mix treated with Termin-8 in the SEW diet had increased ADG and F/G from d 0 to 13 compared to no Termin-8 treatment, but no differences were observed overall (d 0 to 40). Therefore, the use of irradiated spray-dried animal plasma and Termin-8 treated spray-dried animal plasma and base mix improves growth performance in nursery pigs during the initial period after weaning

Effects of Potential Detoxifying Agents on Growth Performance and Deoxynivalenol (DON) Urinary Balance Characteristics of Nursery Pigs Fed DON-Contaminated Wheat

Two experiments were conducted to evaluate the effects of detoxifying agents on the growth performance of nursery pigs fed diets contaminated with deoxynivalenol (DON). Naturally DON-contaminated wheat (6 ppm) replaced noncontaminated wheat in diets to achieve desired dietary DON concentrations. Basal ingredients were tested for mycotoxin and amino acid content prior to diet manufacturing. Diets were pelleted at 180˚F with a 45-s conditioning time. A total of 238 barrows and gilts (PIC 327 × 1050; initially 29.6 ± 5.6 lb and 42 d of age) were used in a 21-d growth study. Pens of pigs were allotted by BW to 1 of 5 treatments in a completely randomized design with a 2 × 2 + 1 factorial arrangement. The 5 experimental diets included the following components, 1) positive control (PC; \u3c0.5 mg/kg DON); 2) PC + 1.0% Product X (Nutriquest LLC, Mason City, IA); 3) negative control (NC; 4.0 mg/kg DON); 4) NC + 1.0% Product X; and 5) NC + 1.0% sodium metabisulfite (SMB; Samirian Chemicals, Campbell, CA). There were 6 or 7 replicate pens per treatment and 7 pigs per pen. Chemical analysis indicated a low level of fumonisin (\u3c1 ppm) was present but that all DON concentrations matched calculated values. Analyzed DON concentrations were decreased by 92% when pelleted with SMB. Overall (d 0 to 21), a DON × Product X interaction was observed for ADG (P \u3c 0.05) and ADFI (P \u3c 0.10). Adding Product X to PC diets had no effect on ADG or ADFI; however, when added to NC diets, ADG, and ADFI became worse. As anticipated, DON reduced (P \u3c 0.001) ADG, ADFI, and F/G by 24, 16, and 10%, respectively. Deoxynivalenol-associated reductions in ADG were most distinct (50%) during the initial period (0.42 vs. 0.84 lb from d 0 to 7). Adding SMB to NC diets improved (P \u3c 0.01) ADG, ADFI, and F/G compared to pigs fed the NC alone, and also improved (P \u3c 0.02) ADG and F/G compared to pigs fed PC diets. A concurrent urinary balance experiment was conducted using diets 3 to 5 from Exp. 1 to evaluate Product X and SMB on DON urinary metabolism. A 10-d adaptation was followed by a 7-d collection using 24 barrows in a randomized complete block design. Pigs fed NC + SMB diet had greater urinary output (P \u3c 0.05) than pigs fed NC + Product X, with NC pigs intermediate. Daily DON excretion was lowest (P \u3c 0.05) in the NC + SMB pigs. However, as a percentage of daily DON intake, NC + SMB fed pigs excreted more DON than they consumed (164%), greater (P \u3c 0.001) than pigs fed the NC (59%) or NC + Product X (48%), and indicative of degradation of DON back to the parent DON molecule. Overall, Product X did not alleviate DON effects on growth nor did it reduce DON absorption and excretion. However, hydrothermally processing DON-contaminated diets with 1.0% SMB restored ADFI and improved F/G. Even so, the urinary balance experiment revealed that some of the converted DON-sulfonate could degrade back to DON under physiological conditions. While SMB appears promising to restore performance in pelleted DON-contaminated diets, additional research needs to address handling and long-term supplementation concerns and to evaluate the stability of the DON-sulfonate conversion

Phenotypic Variation in the Group A Streptococcus Due to Natural Mutation of the Accessory Protein-Encoding Gene rocA

Populations of a bacterial pathogen, whether recovered from a single patient or from a worldwide study, are often a heterogeneous mix of genetically and phenotypically divergent strains. Such heterogeneity is of value in changing environments and arises via mechanisms such as gene gain or gene mutation. Here, we identify an isolate of serotype M12 group A Streptococcus (GAS) (Streptococcus pyogenes) that has a natural mutation in rocA, which encodes an accessory protein to the virulence-regulating two-component system CovR/CovS (CovR/S). Disruption of RocA activity results in the differential expression of multiple GAS virulence factors, including the anti-phagocytic hyaluronic acid capsule and the chemokine protease SpyCEP. While some of our data regarding RocA-regulated genes overlaps with previous studies, which were performed with isolates of alternate GAS serotypes, some variability was also observed. Perhaps as a consequence of this alternate regulatory activity, we discovered that the contribution of RocA to the ability of the M12 isolate to survive and proliferate in human blood ex vivo is opposite that previously observed in M1, M3, and M18 GAS strains. Specifically, rocA mutation reduced, rather than enhanced, survival of the isolate. Finally, we also present data from an analysis of rocA transcription and show that rocA is transcribed in both mono- and polycistronic mRNAs. In aggregate, our data provide insight into the important regulatory role of RocA and into the mechanisms and consequences of GAS phenotypic heterogeneity. IMPORTANCE This study investigates the regulatory and phenotypic consequences of a naturally occurring mutation in a strain of the bacterial pathogen the group A Streptococcus (Streptococcus pyogenes). We show that this mutation, which occurs in a regulator-encoding gene, rocA, leads to altered virulence factor expression and reduces the ability of this isolate to survive in human blood. Critically, the blood survival phenotype and the assortment of genes regulated by RocA differ compared to previous studies into RocA activity. The data are consistent with there being strain-or serotype-specific variability in RocA function. Given that phenotypic variants can lead to treatment failures and escape from preventative regimes, our data provide information with regard to a mechanism of phenotypic variation in a prevalent Gram-positive pathogen

Energy Spectra, Altitude Profiles and Charge Ratios of Atmospheric Muons

We present a new measurement of air shower muons made during atmospheric ascent of the High Energy Antimatter Telescope balloon experiment. The muon charge ratio mu+ / mu- is presented as a function of atmospheric depth in the momentum interval 0.3-0.9 GeV/c. The differential mu- momentum spectra are presented between 0.3 and about 50 GeV/c at atmospheric depths between 13 and 960 g/cm^2. We compare our measurements with other recent data and with Monte Carlo calculations of the same type as those used in predicting atmospheric neutrino fluxes. We find that our measured mu- fluxes are smaller than the predictions by as much as 70% at shallow atmospheric depths, by about 20% at the depth of shower maximum, and are in good agreement with the predictions at greater depths. We explore the consequences of this on the question of atmospheric neutrino production.Comment: 11 pages, 8 figures, to appear in Phys. Rev. D (2000

Identification of a triplet pair intermediate in singlet exciton fission in solution.

Singlet exciton fission is the spin-conserving transformation of one spin-singlet exciton into two spin-triplet excitons. This exciton multiplication mechanism offers an attractive route to solar cells that circumvent the single-junction Shockley-Queisser limit. Most theoretical descriptions of singlet fission invoke an intermediate state of a pair of spin-triplet excitons coupled into an overall spin-singlet configuration, but such a state has never been optically observed. In solution, we show that the dynamics of fission are diffusion limited and enable the isolation of an intermediate species. In concentrated solutions of bis(triisopropylsilylethynyl)[TIPS]--tetracene we find rapid (<100 ps) formation of excimers and a slower (∼ 10 ns) break up of the excimer to two triplet exciton-bearing free molecules. These excimers are spectroscopically distinct from singlet and triplet excitons, yet possess both singlet and triplet characteristics, enabling identification as a triplet pair state. We find that this triplet pair state is significantly stabilized relative to free triplet excitons, and that it plays a critical role in the efficient endothermic singlet fission process.H.L.S was supported by the Winton Programme for the Physics of Sustainability and A.J.M received funding from the Engineering and Physical Sciences Research Council.This is the accepted manuscript. The final version is available at http://www.pnas.org/content/112/25/7656.abstract

Oryzomyine rodents

376 p. : ill., maps (1 col.) ; 26 cm.Includes bibliographical references (p. 324-337)."We describe the morphological species boundaries and geographic distributions of 10 Neotropical Oryzomys based on analyses of museum specimens (skins and skulls, examples preserved in fluid, chromosomal spreads, and information about collection sites from skin tags, field catalogs, and other sources). These species have been regarded as members of an Oryzomys capito complex and for a long time were consolidated into a single entity identified as O. capito. Our study documents the following: 1. Defining the limits of species within the O. capito complex first requires a comprehensive review and rigorous definition of O. capito itself. We consider Fischer's (1814) Mus megacephalus to be valid and available, designate a neotype to bear the name, and reinstate it as a senior synonym of capito Olfers (1818). We then provide a working definition of O. megacephalus and its close relative, O. laticeps, derived from analyses of morphometric variation, estimates of geographic distributions, and evaluations of synonyms. In our view, O. megacephalus occurs in Amazonia but also extends into eastern Paraguay; its synonyms are capito Olfers (1818), cephalotes Desmarest (1819), velutinus Allen and Chapman (1893), goeldi Thomas (1897), modestus Allen (1899), and perenensis Allen (1901). Oryzomys laticeps Lund (1840) occurs in the Atlantic Forest region of eastern Brazil. We designate a lectotype for laticeps and allocate the names saltator Winge (1887) and oniscus Thomas (1904) as synonyms. 2. We provide the first comprehensive taxonomic revision of Oryzomys yunganus Thomas (1902). Its range covers tropical evergreen rainforest formations in the Guiana Region and the Amazon Basin where, as documented by voucher specimens, it has been collected at the same localities as O. megacephalus, O. nitidus, and O. macconnelli. Specimens of O. yunganus can be distinguished from those of the other three by a combination of body size, pelage texture and coloration, pattern of carotid arterial circulation, occlusal patterns of second upper and lower molars, cranial proportions, and chromosomal features. Appreciable intraspecific geographic variation occurs in diploid number of chromosomes and frequency of occurrence of the hypothenar plantar pad, but sampling inadequacies obscure the significance of this variation. Large body size is characteristic of populations in the western Amazon Basin and in the tepui region of eastern Venezuela; smaller size characterizes populations in the Guianas and along the eastern margin of the Amazon Basin. No other scientific name has been correctly associated with the species. Samples from Mirador, Palmera, and Mera in the western Andean foothills of central Ecuador possess a combination of pelage, cranial, and dental traits that distinguish them from all samples of O. yunganus. These specimens are the basis for a new species we describe here, one that is more closely related to O. yunganus than to any other member of the former O. 'capito' complex. 3. We redescribe Oryzomys bolivaris (reviewed by Pine, 1971, under the name O. bombycinus), amplify its geographic range, and contrast it with O. talamancae and O. alfaroi, two sympatric congeners with which it is often confused. A distinctive set of morphological traits allows unambiguous identification of specimens belonging to O. bolivaris. It is a trans-Andean species recorded from very wet tropical evergreen rain forests extending from eastern Honduras and Nicaragua through Costa Rica and Panamá to western Colombia and Ecuador. Allen's (1901) bolivaris is the oldest name for this species; castaneus Allen (1901), rivularis Allen (1901), bombycinus Goldman (1912), alleni Goldman (1915), and orinus Pearson (1939) are synonyms. 4. We revise the definition of Oryzomys talamancae Allen (1891) provided by Musser and Williams (1985), document additional specimens, describe karyotypes from Ecuadoran and Venezuelan samples, and contrast its morphology, chromosomes, and distribution with those of O. alfaroi and O. megacephalus. The geographic distribution of O. talamancae is also trans-Andean, but it inhabits a wider variety of habitats than does O. bolivaris. We also provide a new synonymy and identify the following scientific names as synonyms of O. talamancae: mollipilosus Allen (1899), magdalenae Allen (1899), villosus Allen (1899), sylvaticus Thomas (1900), panamensis Thomas (1901), medius Robinson and Lyon (1901), and carrikeri Allen (1908). 5. We present hypotheses of species boundaries of four morphologically similar species that we identify as members of the Oryzomys nitidus group: O. nitidus Thomas (1884), O. macconnelli Thomas (1910), O. russatus Wagner (1848), and a species described as new. We recognize the four species by morphological and chromosomal traits, and contrast characteristics of each species with one another. One synonym, boliviae Thomas (1901), is associated with O. nitidus, and two scientific names, incertus Allen (1913) and mureliae Allen (1915), are allocated to O. macconnelli. Synonyms of O. russatus are physodes Brants (1827), intermedia Leche (1886), coronatus Winge (1887), lamia Thomas (1901), legatus Thomas (1925), kelloggi Ávila-Pires (1959), and moojeni Ávila-Pires (1959). We designate lectotypes for russatus and intermedia and identify the holotype of coronatus. Based on voucher specimens, the geographic distribution of O. nitidus is mainly along the Andean foothills and adjacent lowlands in Perú, Bolivia, and nearby western Brazil, but scattered records document its eastward extension through south-central Brazil to Paraguay and northeastern Argentina. Oryzomys macconnelli inhabits the tropical evergreen rain forests of Amazonia. Its distribution partially overlaps that of O. nitidus in western Amazonia, where the two species have been collected together at one locality in Perú, and it is sympatric with the new species, which is recorded only from the lower regions of rios Xingu and Tocantins in northern Pará, Brazil. The distribution of O. russatus is documented by specimens from southeastern and south-central Brazil, southern Bolivia, and northern Argentina; its range is allopatric to those of O. macconnelli, the new species, and O. nitidus except in southern Bolivia, where the latter was collected at the same site with O. russatus. We also examined types and descriptions of taxa associated with Oryzomys subflavus and O. ratticeps to determine if any of those names actually reference members of the O. nitidus group. Although the original description of subflavus Wagner (1842) is vague, the holotype clearly represents an example of that very distinctive species; vulpinus Lund (1840), for which we designate a lectotype, and vulpinoides Schinz (1845) are synonyms of O. subflavus. The oldest name for the species currently known as Oryzomys ratticeps is Mus angouya Fischer (1814), a name not based on a specimen but on Azara's (1801) description of 'Rat troisième, ou Rat Angouya.' Azara's account is so general that it could also apply to individuals of O. subflavus, O. nitidus, or O. russatus. To stabilize the nomenclature of these species, we designate a neotype for Mus angouya Fischer (1814) and treat the following scientific names as synonyms: buccinatus Olfers (1818), leucogaster Wagner (1845), ratticeps Hensel (1872), rex Winge (1887), tropicius Thomas (1924), and paraganus Thomas (1924). We also designate lectotypes for leucogaster and ratticeps. We have not analyzed phylogenetic relationships among the species in the former O. 'capito' complex discussed here. Documenting morphological and distributional boundaries of other biological species now grouped in the genus Oryzomys (alfaroi and its close relatives, for example) must precede, in our view, attempts at phylogenetic reconstruction"--P. 5-6

The Energy Spectra and Relative Abundances of Electrons and Positrons in the Galactic Cosmic Radiation

Observations of cosmic-ray electrons and positrons have been made with a new balloon-borne detector, HEAT (the "High-Energy Antimatter Telescope"), first flown in 1994 May from Fort Sumner, NM. We describe the instrumental approach and the data analysis procedures, and we present results from this flight. The measurement has provided a new determination of the individual energy spectra of electrons and positrons from 5 GeV to about 50 GeV, and of the combined "all-electron" intensity (e+ + e-) up to about 100 GeV. The single power-law spectral indices for electrons and positrons are alpha = 3.09 +/- 0.08 and 3.3 +/- 0.2, respectively. We find that a contribution from primary sources to the positron intensity in this energy region, if it exists, must be quite small.Comment: latex2e file, 30 pages, 15 figures, aas2pp4.sty and epsf.tex needed. To appear in May 10, 1998 issue of Ap.