Case ofP Research Articles

Honey constituents up-regulate detoxification and immunity genes in the western honey bee Apis mellifera

As a managed pollinator, the honey bee Apis mellifera is critical to the American agricultural enterprise. Recent colony losses have thus raised concerns; possible explanations for bee decline include nutritional deficiencies and exposures to pesticides and pathogens. We determined that constituents found in honey, including p-coumaric acid, pinocembrin, and pinobanksin 5-methyl ether, specifically induce detoxification genes. These inducers are primarily found not in nectar but in pollen in the case of p-coumaric acid (a monomer of sporopollenin, the principal constituent of pollen cell walls) and propolis, a resinous material gathered and processed by bees to line wax cells. RNA-seq analysis (massively parallel RNA sequencing) revealed that p-coumaric acid specifically up-regulates all classes of detoxification genes as well as select antimicrobial peptide genes. This up-regulation has functional significance in that that adding p-coumaric acid to a diet of sucrose increases midgut metabolism of coumaphos, a widely used in-hive acaricide, by ∼60%. As a major component of pollen grains, p-coumaric acid is ubiquitous in the natural diet of honey bees and may function as a nutraceutical regulating immune and detoxification processes. The widespread apicultural use of honey substitutes, including high-fructose corn syrup, may thus compromise the ability of honey bees to cope with pesticides and pathogens and contribute to colony losses.

Combined Short Course Low Molecular Weight Heparin and Calf Compression Therapy in Prevention of Deep Vein Thrombosis after Total Knee Replacement: A Randomized Prospective Study

Background and aims: Anti-coagulation is an important component of post-operative Venous-Thombo-Embolic (VTE) prophylaxis but can be associated with significant complications including hemorrhage. Current guidelines favour anti-coagulation for ≥ 14 days with little evidence evaluating the efficacy of anticoagulation <14 days. Our study hypothesizes that short course Low-Molecular-Weight-Heparin (LMWH for 5-7 days) in combination with Calf Compression Device (CCD) is equally effective as standard therapy LMWH (14 days) in preventing VTE and related events amongst patients undergoing Total-Knee-Replacement (TKR). Methods: Eighty-three patients undergoing TKR were randomly allocated to either: Group 1 short course LMWH (5-7 days) with CCD or Group 2 standard course LMWH only (14 days). Patients were followed up daily for five days post-operative and then at regular intervals for twelve weeks assessing for: deep-vein-thrombosis and pulmonary embolus, bleeding, exaggerated pain, wound infection, leg swelling and need for extended hospitalization beyond 5 days. Incidence comparisons between groups were made using Pearson’s chi-square or Fischer’s Exact tests and an accepted group treatment difference of 15% was selected based on previous studies to calculate equivalence powers. Results: The incidence of DVT was equal between groups (n=3), 2% (95% CI -13.4, 14.1%). There was a single case of asymptomatic PE in the short course group though the group difference was not significant (p=0.486). Patients in the short course therapy group also demonstrated significantly lower rates of post operative leg swelling (p=0.004). Group comparisons for all other study endpoints did not reach significance. Conclusions: In this study combined short course therapy was equally effective as standard therapy in preventing DVT and non-fatal PE, and superior to standard therapy in limiting post-operative leg swelling amongst patients undergoing TKR. Trial registered at Australian New Zealand Trial Registry: ACTRN12613000240741.

Synthesis and Antibacterial and Antibiofilm Activity of Iron Oxide Glycerol Nanoparticles Obtained by Coprecipitation Method

The glycerol iron oxide nanoparticles (GIO‐NPs) were obtained by an adapted coprecipitation method. The X‐ray diffraction (XRD) studies demonstrate that GIO‐NPs were indexed into the spinel cubic lattice with a lattice parameter of 0.835 nm. The refinement of XRD spectra indicated that no other phases except maghemite were detected. The adsorption of glycerol on iron oxide nanoparticles was investigated by Fourier transform infrared (FTIR) spectroscopy. On the other hand, this work implicated the use of GIO‐NPs in antibacterial studies. The results indicate that, in the case of P. aeruginosa 1397 biofilms, at concentrations from 0.01 mg/mL to 0.625 mg/mL, the glycerol iron oxide inhibits the ability of this strain to develop biofilms on the inert substratum.

Failure of Supervised Chloroquine and Primaquine Regimen for the Treatment ofPlasmodium vivaxin the Peruvian Amazon

The widespread use of primaquine (PQ) and chloroquine (CQ), together, may be responsible for the relatively few, isolated cases of chloroquine-resistant P. vivax (CQRPV) that have been reported from South America. We report here a case of P. vivax from the Amazon Basin of Peru that recurred against normally therapeutic blood levels of CQ. Four out of 540 patients treated with combination CQ and PQ had a symptomatic recurrence of P. vivax parasitemia within 35 days of treatment initiation, possibly indicating CQ failure. Whole blood total CQ level for one of these four subjects was 95 ng/ml on the day of recurrence. Based on published criteria that delineate CQRPV as a P. vivax parasitemia, either recrudescence or relapse, that appears against CQ blood levels >100 ng/mL, we document the occurrence of a P. vivax strain in Peru that had unusually high tolerance to the synergistic combination therapy of CQ + PQ that normally works quite well.

Removal Efficiency of Cr6+by IndigenousPichiasp. Isolated from Textile Factory Effluent

Resistance of the indigenous strains P. jadinii M9 and P. anomala M10, to high Cr6+ concentrations and their ability to reduce chromium in culture medium was studied. The isolates were able to tolerate chromium concentrations up to 104 μg mL−1. Growth and reduction of Cr6+ were dependent on incubation temperature, agitation, Cr6+ concentration, and pH. Thus, in both studied strains the chromium removal was increased at 30°C with agitation. The optimum pH was different, with values of pH 3.0 and pH 7.0 in the case of P. anomala M10 and pH 7.0 using P. jadinii M9. Chromate reduction occurred both in intact cells (grown in culture medium) as well as in cell-free extracts. Chromate reductase activity could be related to cytosolic or membrane-associated proteins. The presence of a chromate reductase activity points out a possible role of an enzyme in Cr6+ reduction.

Origin of multiple periodicities in the Fourier power spectra of the Plasmodium falciparum genome

BackgroundFourier transforms and their associated power spectra are used for detecting periodicities and protein-coding genes and is generally regarded as a well established technique. Many of the periodicities which have been found with this method are quite well understood such as the periodicity of 3 nt which is associated to codon usage. But what is the origin of the peculiar frequency multiples k/21 which were reported for a tiny section of chromosome 2 in P. falciparum? Are these present in other chromosomes and perhaps in related organisms? And how should we interpret fractional periodicities in genomes?ResultsWe applied the binary indicator power spectrum to all chromosomes of P. falciparum, and found that the frequency overtones k/21 are present only in non-coding sections. We did not find such frequency overtones in any other related genomes. Furthermore, the frequency overtones were identified as artifacts of the way the genome is encoded into a numerical sequence, that is, they are frequency aliases. By choosing a different way to encode the sequence the overtones do not appear. In view of these results, we revisited early applications of this technique to proteins where frequency overtones were reported.ConclusionsSome authors hinted recently at the possibility of mapping artifacts and frequency aliases in power spectra. However, in the case of P. falciparum the frequency aliases are particularly strong and can mask the 1/3 frequency which is used for gene detecting. This shows that albeit being a well known technique, with a long history of application in proteins, few researchers seem to be aware of the problems represented by frequency aliases.

Pythium aphanidermatum Infection following Combat Trauma

Pythium aphanidermatum is a fungus-like plant pathogen which has never been reported as a cause of human infection. We report a case of P. aphanidermatum invasive wound infection in a 21-year-old male injured during combat operations in Afghanistan.

Spread of Pseudomonas fluorescens Due to Contaminated Drinking Water in a Bone Marrow Transplant Unit

Pseudomonas infections are an important cause of morbidity and mortality in immunocompromised patients. We present here data for the spread of Pseudomonas fluorescens caused by a contaminated drinking water dispenser in a bone marrow transplant unit. Over a 1-month period we observed a sharp increase in the isolation of P. fluorescens from weekly pharyngeal surveillance swabs. Environmental samples were taken from a variety of water sources throughout the unit. These samples were cultured on cetrimide agar medium, and isolates were epidemiologically characterized by antibiotic susceptibility patterns and molecular typing methods. Nine patients became colonized with P. fluorescens, and six out of the nine developed febrile neutropenia. P. fluorescens was cultured after the filtration of 100 ml of drinking water from one of two stand-alone chiller units supplying cooled bottled water to the bone marrow transplant unit. All other environmental samples were negative. There were no further cases of P. fluorescens colonization after the contaminated dispenser was removed. Molecular typing showed that all P. fluorescens isolates were identical by both random amplification of polymorphic DNA PCR and pulsed-field gel electrophoresis. We recommend that such bottled water supplies not be used in high-risk areas or be subject to regular microbiological monitoring.

Blow-up rate of type II and the braid group theory

A solution u u of a Cauchy problem or a Cauchy-Dirichlet problem for a semilinear heat equation \[ u t = Δ u + u p u_t = \Delta u + u^p \] with nonnegative initial data u 0 u_0 is said to undergo type II blow-up at t = T t = T if \[ lim sup t ↗ T ( T − t ) 1 / ( p − 1 ) | u ( t ) | ∞ = ∞ . \limsup _{t \nearrow T} \; (T-t)^{1/(p-1)} |u(t)|_\infty = \infty . \] Let φ ∞ \varphi _\infty be the radially symmetric singular steady state of the Cauchy problem. Suppose that u 0 ∈ L ∞ u_0 \in L^\infty is a radially symmetric function such that u 0 − φ ∞ u_0 - \varphi _\infty and ( u 0 ) t (u_0)_t change sign at most finitely many times. By application of the braid group theory, we determine the exact blow-up rate of solution with initial data u 0 u_0 which undergoes type II blow-up in the case of p &gt; p J L p &gt; p_{_{JL}} , where p J L p_{_{JL}} is the exponent of Joseph and Lundgren.

Evaluation of Sensitivity of Multiplex PCR for Detection of Mycobacterium tuberculosis and Pneumocystis jirovecii in Clinical Samples

A multiplex PCR assay for the simultaneous detection of Mycobacterium tuberculosis and Pneumocystis jirovecii was developed using IS6110-based detection for M. tuberculosis and mitochondrial large-subunit (mtLSU) rRNA gene detection for P. jirovecii. Ninety-five pulmonary blinded samples were examined using the developed multiplex PCR assay, and the results were compared with those obtained by the single nested PCRs targeting IS6110 for M. tuberculosis and mtLSU rRNA for P. jirovecii. Of the 95 pulmonary samples tested, the multiplex nested PCR developed here could detect 36 cases of M. tuberculosis infection, 35 cases of P. jirovecii infection, and 17 cases of M. tuberculosis and P. jirovecii coinfections. The sensitivities of the multiplex nested PCR in detecting M. tuberculosis and P. jirovecii were 92.1% and 81.4%, respectively, whereas the specificities in detecting M. tuberculosis and P. jirovecii were 98.2% and 100%, respectively.

First Report of Bloodstream Infection Caused by Pseudomonas fulva

Pseudomonas fulva has not yet been isolated from humans as a pathogen. Herein, we report the first case of P. fulva bacteremia in a patient hospitalized due to trauma. The species was identified using biochemical and molecular genetic analyses of the 16S rRNA, gyrB, rpoB, and rpoD genes.

Nutrients and disturbance history in twoPlantagospecies: maternal effects as a clue for observed dichotomy between resprouting and seeding strategies

We assessed the role of nutrients and disturbance experienced by mothers (maternal effects) in the growth of progeny in a pot experiment using twoPlantagospecies. Photosynthetic capacity, biomass allocation and fecundity were measured. Offspring of plants grown in nutrient poor conditions produced more leaves, spikes and longer leaves and in case ofP. lanceolata, they had also higher photosynthetic capacity. The progeny ofP. mediamothers that had resprouted after disturbance was favored in nutrient poor conditions whereas the progeny of undisturbed plants was favored in nutrient rich conditions.This study demonstrates that maternal effects may play a role in the success of either a seeding or a resprouting strategy in environments with different nutrient availability. Moreover, we showed that alteration of photosynthetic capacity, even during adult stages, is a mechanism through which maternal plants may impact their progeny.

Novel pfdhps Haplotypes among Imported Cases of Plasmodium falciparum Malaria in the United Kingdom

Treatment of acute malaria caused by Plasmodium falciparum may include long-half-life drugs, such as the antifolate combination sulfadoxine-pyrimethamine (SP), to provide posttreatment chemoprophylaxis against parasite recrudescence or delayed emergence from the liver. An unusual case of P. falciparum recrudescence in a returned British traveler who received such a regimen, as well as a series of 44 parasite isolates from the same hospital, was analyzed by PCR and direct DNA sequencing for the presence of markers of parasite resistance to chloroquine and antifolates. The index patient harbored a mixture of wild-type and resistant pfdhfr and pfdhps alleles upon initial presentation. During his second malaria episode, he harbored only resistant parasites, with the haplotypes IRNI (codons 51, 59, 108, and 164) and SGEAA (codons 436, 437, 540, 581, and 613) at these two loci, respectively. Analysis of isolates from 44 other patients showed that the pfdhfr haplotype IRNI was common (found in 81% of cases). The SGEAA haplotype of pfdhps was uncommon (found only in eight cases of East African origin [17%]). A previously undescribed mutation, I431V, was observed for seven cases of Nigerian origin, occurring as one of two haplotypes, VAGKGS or VAGKAA. The presence of this mutation was also confirmed in isolates of Nigerian origin from the United Kingdom Malaria Reference Laboratory. The presence of the pfdhps haplotype SGEAA in P. falciparum parasites of East African origin appears to compromise the efficacy of treatment regimens that include SP as a means to prevent recrudescence. Parasites with novel pfdhps haplotypes are circulating in West Africa. The response of these parasites to chemotherapy needs to be evaluated.

Chitosan Acetate Bandage as a Topical Antimicrobial Dressing for Infected Burns

An engineered chitosan acetate bandage preparation (HemCon) is used as a hemostatic dressing, and its chemical structure suggests that it should also be antimicrobial. We previously showed that when a chitosan acetate bandage was applied to full-thickness excisional wounds in mice that had been infected with pathogenic bioluminescent bacteria (Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus), it was able to rapidly kill the bacteria and save the mice from developing fatal infections. Wound healing was also stimulated. In the present study, we asked whether a chitosan acetate bandage could act as a topical antimicrobial dressing when it was applied to third-degree burns in mice contaminated with two of these bacterial species (P. aeruginosa and P. mirabilis). Preliminary experiments established the length of burn time and the number of bacteria needed to produce fatal infections in untreated mice and established that the chitosan acetate bandage could adhere to the infected burn for up to 21 days. In the case of P. aeruginosa infections, the survival rate of mice treated with the chitosan acetate bandage was 73.3% (whereas the survival rate of mice treated with a nanocrystalline silver dressing was 27.3% [P = 0.0055] and that of untreated mice was 13.3% [P < 0.0002]). For P. mirabilis infections, the comparable survival rates were 66.7%, 62.5%, and 23.1% respectively. Quantitative bioluminescent signals showed that the chitosan acetate bandage effectively controlled the growth of bacteria in the burn and prevented the development of systemic sepsis, as shown by blood culture. These data suggest that chitosan acetate bandage is efficacious in preventing fatal burn infections.

EPR/rheometric studies on radical kinetics in melt polyolefin elastomer initiated by dicumyl peroxides

Peroxide-initiated reaction of poly(ethylene- co-α-butene) (EB), a kind of polyolefin elastomer (POE), was studied at elevated temperatures using an on-line electron paramagnetic resonance (EPR) spectrometer and was also evaluated by monitoring the viscosity of the reaction system on a rotational rheometer. It is clear that the reaction process experiences the free radical mechanisms. According to the EPR spectra, notable changes in signal hyperfine structure, the intensity and lifetime of the radical were recognized. Different from the case of PE and PP modified by peroxide, there is a new type of EPR signal, which is assisted to the tertiary alkyl radicals. And it is verified that the primary alkyl radicals are first produced at elevated temperatures. A rheokinetic analysis was made by EPR and rheology. The kinetic coefficients of coupling and disproportionating reactions were not fixed, but the functions of the reacting time or the system viscosity. Accordingly, the kinetics is substantially controlled by diffusion of the polymer chains and a formula reflecting this kind of effect of the viscosity on termination rate coefficients is founded.

Modeling of solute transport into sub-aqueous sediments

A model for investigating the solute transport into a sub-aqueous sediment bed, under an imposed standing water surface wave, is developed. Under the assumption of Darcy flow in the bed, a model based on a two-dimensional, unsteady advection–diffusion equation is derived; the relative roles of the advective and diffusive transport are characterized by a Peclet number, Pe. Two solutions for the equation are developed. The first is a basic control volume method using the power-law scheme. The second is a smear-free, modified upwind solution for the special case of Pe → ∞. Results, at a given time step, are reported in terms of a laterally averaged solute verse depth profile. The main result of the paper is to demonstrate that the one-dimensional solute concentration verse depth profile is essentially independent of any numerical dissipation present in the solute field predictions. This demonstration is achieved by (i) using an extensive grid refinement study, and (ii) by comparing Pe → ∞ predictions obtained with the basic and smear-free solutions.

Heat transfer and thermal stress analysis in grooved tubes

Heat transfer and thermal stresses, induced by temperature differences in the internally grooved tubes of heat transfer equipment, have been analysed numerically. The analysis has been conducted for four different kinds of internally grooved tubes and three different mean inlet water velocities. Constant temperature was applied from the external surface of the tube. Energy and governing flow equations were solved using finite difference scheme. Finite element method (FEM) was used to compute the thermal stress fields. Grooving effects on the thermal stress ratio have been discussed. As a result, maximum thermal stress occurs in the case ofp =d for all water inlet velocities. The maximum thermal stress ratio positions inside the tube have been indicated as MX for all investigated cases. In the light of the thermal stress values, various designs can be applied to reduce thermal stress in grooved tubes.

Plasmodium falciparumMalaria: Reduction of Endothelial Cell Apoptosis In Vitro

Organ failure in Plasmodium falciparum malaria is associated with neutrophil activation and endothelial damage. This study investigates whether neutrophil-induced endothelial damage involves apoptosis and whether it can be prevented by neutralization of neutrophil secretory products. Endothelial cells from human umbilical veins were coincubated with neutrophils from healthy donors and with sera from eight patients with P. falciparum malaria, three patients with P. vivax malaria, and three healthy controls. Endothelial apoptosis was demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and annexin V staining. The rate of apoptosis of cells was markedly increased after incubation with patient serum compared to that with control serum. Apoptosis was most pronounced after incubation with sera from two patients with fatal cases of P. falciparum malaria, followed by sera of survivors with severe P. falciparum malaria and, finally, by sera of patients with mild P. falciparum and P. vivax malaria. Ascorbic acid, tocopherol, and ulinastatin reduced the apoptosis rate, but gabexate mesilate and pentoxifylline did not. Furthermore, in fatal P. falciparum malaria, apoptotic endothelial cells were identified in renal and pulmonary tissue by TUNEL staining. These findings show that apoptosis caused by neutrophil secretory products plays a major role in endothelial cell damage in malaria. The antioxidants ascorbic acid and tocopherol and the protease inhibitor ulinastatin can reduce malaria-associated endothelial apoptosis in vitro.

Identification of an Amino Acid Position That Determines the Substrate Range of Integral Membrane Alkane Hydroxylases

Selection experiments and protein engineering were used to identify an amino acid position in integral membrane alkane hydroxylases (AHs) that determines whether long-chain-length alkanes can be hydroxylated by these enzymes. First, substrate range mutants of the Pseudomonas putida GPo1 and Alcanivorax borkumensis AP1 medium-chain-length AHs were obtained by selection experiments with a specially constructed host. In all mutants able to oxidize alkanes longer than C13, W55 (in the case of P. putida AlkB) or W58 (in the case of A. borkumensis AlkB1) had changed to a much less bulky amino acid, usually serine or cysteine. The corresponding position in AHs from other bacteria that oxidize alkanes longer than C13 is occupied by a less bulky hydrophobic residue (A, V, L, or I). Site-directed mutagenesis of this position in the Mycobacterium tuberculosis H37Rv AH, which oxidizes C10 to C16 alkanes, to introduce more bulky amino acids changed the substrate range in the opposite direction; L69F and L69W mutants oxidized only C10 and C11 alkanes. Subsequent selection for growth on longer alkanes restored the leucine codon. A structure model of AHs based on these results is discussed.

Spreading with immunization in high dimensions

We investigate a model of epidemic spreading with partial immunizationwhich is controlled by two probabilities, namely, for first infections,p0, and forreinfections, p. When the two probabilities are equal, the model reduces to directed percolation, while forperfect immunization one obtains the general epidemic process belonging to theuniversality class of dynamical percolation. We focus on the critical behaviour in thevicinity of the directed percolation point, especially for high number of dimensionsd>2. It is argued that the clusters of immune sites are compact for . This observation implies that a recently introduced scaling argument,suggesting a stretched exponential decay of the survival probability forp = pc, in one spatial dimension, wherepc denotes the critical threshold for directed percolation, should apply for any number ofdimensions and perhaps for d = 4 as well. Moreover, we show that the phase transition line, connectingthe critical points of directed percolation and of dynamical percolation,terminates at the critical point of directed percolation with vanishing slope ford<4 and with finite slope for . Furthermore, an exponent is identified for the temporal correlation length for the case ofp = pc and p0 = pc−ϵ, , which is different from the exponent of directed percolation. We also improve numerical estimates of severalcritical parameters and exponents, especially for dynamical percolation ford = 4,5.