1,569 research outputs found

    The complexities of antibiotic action

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    Effect of extrusion on the nutritional value of soybeans and sorghum grain in finishing pigs

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    A total of 112 finishing pigs (avg initial wt of 139 lb) was used to determine the effects of adding extruded soybeans and/or sorghum grain to diets for finishing pigs. Treatments were: 1) sorghum-soybean meal control (sorghum-SBM), 2) extruded soybeans and ground sorghum, 3) SBM and extruded sorghum, and 4) extruded soybeans and sorghum. All diets were isocaloric and isolysinic. Using extruded soybeans and/or sorghum improved efficiency of gain compared to the sorghum-SBM control. This response was apparently related to the improved digestibilities of dry matter and nitrogen with the use of extruded ingredients. Optimum digestibility of dry matter and nitrogen was achieved when just the sorghum was extruded, but optimum growth performance (ie., efficiency of gain) was achieved when extruded sorghum and soybeans were added to the diet.; Swine Day, Manhattan, KS, November 15, 199

    Effect of BMAP-28 Antimicrobial Peptides on Leishmania major Promastigote and Amastigote Growth: Role of Leishmanolysin in Parasite Survival

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    Protozoan parasites are the causative agent of much disease in tropical areas of the world. Currently, the control of these diseases is dependent on outdated drug treatment, with associated high toxicity and drug resistance. There is an urgent need for novel anti-parasitic therapies. One emerging anti-parasitic therapies is Host defence peptides (HDPs). Here we test the HDP BMAP-28 as an anti-leishmanial therapy against two lifecycle stages of Leishmania major, the promastigotes (insect infective form) and the intracellular amastigote (mammalian infective form). Two stereoisomers of BMAP-28, the D-amino acid form (D-BMAP-28) and the retro-inverso form (RI-BMAP-28), were also tested for anti-leishmanial activity. The BMAP-28 form (L-form) was susceptible to degradation by GP63, the metalloproteinase that covers the promastigotes cell surface. However, the BMAP-28 isomers, the D-form and RI-form were resistant, and therefore more potent against the promastigote parasite. Though other anti-leishmanial HDP studies focus on the promastigote form of the parasite, it is the mammalian infective form, the amastigote, which causes the disease symptoms. Here we demonstrate that BMAP-28 and its isomers D-BMAP-28 and RI-BMAP-28 are effective against the amastigote form of the parasite using a macrophage infection model. These findings show that BMAP-28 has excellent potential as a novel anti-leishmanial therapeutic

    Reassessing the Host Defense Peptide Landscape

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    Current research has demonstrated that small cationic amphipathic peptides have strong potential not only as antimicrobials, but also as antibiofilm agents, immune modulators, and anti-inflammatories. Although traditionally termed antimicrobial peptides (AMPs) these additional roles have prompted a shift in terminology to use the broader term host defense peptides (HDPs) to capture the multi-functional nature of these molecules. In this review, we critically examined the role of AMPs and HDPs in infectious diseases and inflammation. It is generally accepted that HDPs are multi-faceted mediators of a wide range of biological processes, with individual activities dependent on their polypeptide sequence. In this context, we explore the concept of chemical space as it applies to HDPs and hypothesize that the various functions and activities of this class of molecule exist on independent but overlapping activity landscapes. Finally, we outline several emerging functions and roles of HDPs and highlight how an improved understanding of these processes can potentially be leveraged to more fully realize the therapeutic promise of HDPs

    The properties of extragalactic radio sources selected at 20 GHz

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    We present some first results on the variability, polarization and general properties of radio sources selected in a blind survey at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of sky. Sources with flux densities above 100 mJy in the AT20G Pilot Survey at declination -60 to -70 were observed at up to three epochs during 2002-4, including near-simultaneous measurements at 5, 8 and 18 GHz in 2003. Of the 173 sources detected, 65% are candidate QSOs, BL Lac objects or blazars, 20% galaxies and 15% faint (b > 22 mag) optical objects or blank fields. On a 1-2 year timescale, the general level of variability at 20 GHz appears to be low. For the 108 sources with good-quality measurements in both 2003 and 2004, the median variability index at 20 GHz was 6.9% and only five sources varied by more than 30% in flux density. Most sources in our sample show low levels of linear polarization (typically 1-5%), with a median fractional polarization of 2.3% at 20 GHz. There is a trend for fainter sources to show higher fractional polarization. At least 40% of sources selected at 20GHz have strong spectral curvature over the frequency range 1-20 GHz. We use a radio `two-colour diagram' to characterize the radio spectra of our sample, and confirm that the radio-source population at 20 GHz (which is also the foreground point-source population for CMB anisotropy experiments like WMAP and Planck) cannot be reliably predicted by extrapolating the results of surveys at lower frequencies. As a result, direct selection at 20 GHz appears to be a more efficient way of identifying 90 GHz phase calibrators for ALMA than the currently-proposed technique of extrapolation from all-sky surveys at 1-5 GHz.Comment: 14-page paper plus 5-page data table. Replaced with published versio

    Analyses of density-dependent effects are needed to understand how and when Wolbachia can control dengue vectors

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    Releases of Wolbachia-infected mosquitoes have been shown to be an effective method of controlling Aedes aegypti, the main vector of dengue fever, in Australia. A study in BMC Biology from Penelope Hancock and others shows that incorporation of density-dependent effects into population models can provide major improvements in understanding how and when the infected populations can become established

    UA3/3/1 Analysis of the Demand for Married Student Housing at WKU, 1966-1967

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    The purpose of this study is to bring forth relevant information needed to determine the feasibility of an investment project for a married student housing complex on the campus of Western Kentucky University. Only the demand side of the market is analyzed; a potential investor will have the construction and land costs for such an enterprise at his disposal. With the information presented in this study it is hoped that a decision to construct a housing complex will be forthcoming. The study group attempted to present information that will allow a potential investor to make an intelligent decision as to the profitability of the investment. It is hoped that the critical questions concerning the investment have been answered by this study. The time period in which the study was carried out was January, 1967 to June, 1967, i.e., the second semester of the 1966-67 school year. The information presented was obtained from a single sample of the married population. Seventy married family units (8.4 percent of the population) were stratified according to class standing (Freshman, Sophomore, Junior, Senior, and Graduate) and then picked randomly within the class stratifications. A more desirable method would have been a sequential sampling method, but the time and expense of the method did not allow its use. Future studies can be carried out in order to substantiate the data presented at this time. The estimated size of the investment would seem to warrant at least one more comprehensive examination of the market in order that a more exact market character can be determined. The study group contacted state institutions that have married housing units in order to see if any useful information could be obtained from their experience in the determination of market character and size of their married students. None of the schools contacted had conducted a market study prior to the construction of such a housing unit. Discovering this factor did not disturb the study group. It was assumed that the market character at the various educational institutions would be significantly different with reference to income, rent, family size, etc., that no useful comparison could be made. The reason for this assumption rests on the fact that the educational institutions differ in such things as type and size of the graduate program and community size and industrial development. These factors have a direct influence on the family unit\u27s income, numbers, and the rate of growth of the married student body. The purpose of contacting the various institutions was to examine the methodology used in the study of the market for married student housing

    Targeting the Pseudomonas aeruginosa Virulence Factor Phospholipase C With Engineered Liposomes.

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    Engineered liposomes composed of the naturally occurring lipids sphingomyelin (Sm) and cholesterol (Ch) have been demonstrated to efficiently neutralize toxins secreted by Gram-positive bacteria such as Streptococcus pneumoniae and Staphylococcus aureus. Here, we hypothesized that liposomes are capable of neutralizing cytolytic virulence factors secreted by the Gram-negative pathogen Pseudomonas aeruginosa. We used the highly virulent cystic fibrosis P. aeruginosa Liverpool Epidemic Strain LESB58 and showed that sphingomyelin (Sm) and a combination of sphingomyelin with cholesterol (Ch:Sm; 66 mol/% Ch and 34 mol/% Sm) liposomes reduced lysis of human bronchial and red blood cells upon challenge with the Pseudomonas secretome. Mass spectrometry of liposome-sequestered Pseudomonas proteins identified the virulence-promoting hemolytic phospholipase C (PlcH) as having been neutralized. Pseudomonas aeruginosa supernatants incubated with liposomes demonstrated reduced PlcH activity as assessed by the p-nitrophenylphosphorylcholine (NPPC) assay. Testing the in vivo efficacy of the liposomes in a murine cutaneous abscess model revealed that Sm and Ch:Sm, as single dose treatments, attenuated abscesses by >30%, demonstrating a similar effect to that of a mutant lacking plcH in this infection model. Thus, sphingomyelin-containing liposome therapy offers an interesting approach to treat and reduce virulence of complex infections caused by P. aeruginosa and potentially other Gram-negative pathogens expressing PlcH

    Transgenic potatoes expressing a novel cationic peptide are resistant to late blight and pink rot

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    Abstract Potato is the world's largest non-cereal crop. Potato late blight is a pandemic, foliar wasting potato disease caused by Phytophthora infestans, which has become highly virulent, fungicide resistant, and widely disseminated. Similarly, fungicide resistant isolates of Phytophthora erythroseptica, which causes pink rot, have also become an economic scourge of potato tubers. Thus, an alternate, cost effective strategy for disease control has become an international imperative. Here we describe a strategy for engineering potato plants exhibiting strong protection against these exceptionally virulent pathogens without deleterious effects on plant yield or vigor. The small, naturally occurring antimicrobial cationic peptide, temporin A, was N-terminally modified (MsrA3) and expressed in potato plants. MsrA3 conveyed strong resistance to late blight and pink rot phytopathogens in addition to the bacterial pathogen Erwinia carotovora. Transgenic tubers remained disease-free during storage for more than 2 years. These results provide a timely, sustainable, effective, and environmentally friendly means of control of potato diseases while simultaneously preventing storage losses

    Probing Unstable Massive Neutrinos with Current Cosmic Microwave Background Observations

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    The pattern of anisotropies in the Cosmic Microwave Background depends upon the masses and lifetimes of the three neutrino species. A neutrino species of mass greater than 10 eV with lifetime between 10^{13} sec and 10^{17} sec leaves a very distinct signature (due to the integrated Sachs-Wolfe effect): the anisotropies at large angles are predicted to be comparable to those on degree scales. Present data exclude such a possibility and hence this region of parameter space. For mν30m_\nu \simeq 30 eV, τ1013\tau \simeq 10^{13} sec, we find an interesting possibility: the Integrated Sachs Wolfe peak produced by the decaying neutrino in low-Ω\Omega models mimics the acoustic peak expected in an Ω=1\Omega = 1 model.Comment: 5 pages, 4 figure
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