Search

Cosmeto-textiles, which allow the administration of molecules when in contact with the skin, are increasingly being developed by cosmetic industries. We have designed an innovative approach for cosmeto-textile products, based on the impregnation of textile fibers with chitosan hydrogels, which have been cross-linked with genipin and loaded with dihydroxyacetone, which is an active component that induces sunless tanning. Dihydroxyacetone-loaded chitosan hydrogels have been prepared and characterized by means of cryogenic scanning electron microscopy (cryo-SEM). The images showed that genipin cross-linking decreases the mesh distance of hydrogels. The release of dihydroxyacetone from these cross-linked genipin chitosan hydrogels has been studied by a dialysis membrane method. These dihydroxyacetone-loaded chitosan hydrogels have been incorporated to polyamide textiles by a simple padding technique. The presence of dihydroxyacetone on these textiles has been detected by hyperspectral imaging on a dark field high resolution optical microscope. Finally, the performance of fabrics as cosmeto-textiles, with a tanning effect, has been evaluated by skin-colorimetry measured with an evaluation panel of 10 people. The results have demonstrated that dihydroxyacetone-loaded textiles produce a tanning effect on skin, and incorporation of dihydroxyacetone-loaded chitosan hydrogels into polyamide fabrics represents a friendly and appropriate strategy to obtain a cosmeto-textile with tanning effect. © The Author(s) 2019., The authors acknowledge financial support from CDTI (INNPACTO program), grant IPT-300000-2010-0026. The optical microscope observations have been performed by the Nanostructured Liquid Characterization Unit, located at the Institute of Advanced Chemistry of Catalonia (IQAC), belonging to the Spanish National Research Council (CSIC) and affiliated to the NANBIOSIS ICTS of the Biomedical Networking Center (CIBER-BBN).

Crosslinked chitosan-based nanofilms (thickness approximately 40 nm) were prepared using a naturally occurring and nontoxic reagent, genipin, and the surface properties were studied as a function of crosslinking degree and pH, by combining three techniques: dynamic contact angle of sessile drops, quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). The results showed a pH-response of these crosslinked chitosan nanofilms, which swelled at pH 3 and shrank at pH 6. This transition was facilitated by chitosan crosslinking, although the wettability, studied by contact angle measurements, decreased with crosslinking. QCM-D and AFM were used to study the swelling capacity and elastic properties of crosslinked chitosan nanofilms, demonstrating that the response of the nanofilms was fully reversible between pH 3 and 6, but irreversible changes occurred at pH 9. QCM-D showed variations in frequency (Δf) generated by the processes of swelling/shrinkage and variations in dissipation (ΔD), related to the changes in the structure of chitosan nanofilms under different pH values. Under various pH conditions, the AFM results also showed swelling at pH 3 and shrinking at pH 6, observing an increase in the elastic modulus from ≈500 MPa at pH 3 to ≈700 MPa at pH 6. These results allowed us to understand the pH-sensitive properties of genipin-crosslinked chitosan nanofilms, which can be very useful in smart biomaterial-based textiles., The authors acknowledge the financial support from the InForm grant (FP7-CSA-CA 233533) and the support of the Surface and Corrosion Science division from Royal Institute of Technology (KTH) in Stockholm (Sweden), where these experiments were carried out. The authors also greatly thank the Spanish Ministry of Science and Innovation (CTQ2017-84998-P project) and the Catalan Government (2017SGR1778 grant). In addition, the European Regional Development Fund (“Fondo Europeo de Desarrollo Regional”, FEDER) is also appreciated. The “Grupo de Nanotecnología Farmacéutica”, of the Faculty of Pharmacy and Food Sciences, at the University of Barcelona (UB), which forms an R&D Associated Unit to CSIC, is also acknowledged. Moreover, the authors are very grateful to Karin Persson (RISE Research Institutes of Sweden, Stockholm) and Per Claesson (Royal Institute of Technology, KTH, Sweden), for their support and useful discussions, as well as facilitating experimental equipment.

Research on colloidal dispersions has led to several reports of structured gels made of aggregated polymeric particles. In a previous work, we formed for the first time a gel from lipid vesicles with a high content of water; we hypothesized that electrostatic charge at the membranes promoted gelation. In the present work, we studied three gels formed from vesicles with different molar ratios of uncharged/charged lipids (3:1, 20:1, and 80:1) to correlate electrostatic balance with structure and rheology. X-ray scattering indicated that the structural unit of these gels is the lipid bilayer. Fluorescent confocal microscopy showed that the microstructure of the gels varied with charge. The sample with the highest amount of charge (3:1) presented a mesh-like lipid phase, made from small aggregates, while a decrease of charge formed bigger lipid flocs that packed tightly. As seen by oscillatory rheology, these structural differences altered the viscoelastic behavior of the gels: The sample with intermediate charge ratio (20:1) had the largest resistance to deformation, while deviations from this ratio decreased its rigidity. Knowledge of how electrostatic balance affects gel properties will help to adequate gel composition to specific applications., The authors are grateful to Lipoid GmbH for kindly providing HSPC and DOTAP and to MINECO (Spain) for funding this work with the RTC-2016-4957-1 project.

Infection with Toxoplasma gondii in humans has usually been related to the consumption of raw, undercooked or cured meat. Our study is based on the detection of T. gondii in cured legs and shoulders made from 100% Iberian sows fed mainly with acorn and raised as outdoor livestock in Aracena (Spain), which having been elaborated following a specific curing process (time period and location). An outdoor farm with a total of 636 animals was studied, showing a seroprevalence of 10% for the parasite T. gondii. Twenty individuals were chosen to be experimentally infected and slaughtered 60 days post-infection. Their legs and shoulders were processed to make 100% Iberian ham legs and shoulders. The meat ready to be eaten was analyzed by quantification and viability assays using magnetic capture real-time qPCR and bioassay techniques proving that this specific traditional "Cinco Jotas" curing process 100% Iberian ham is strong enough to eliminate the parasite T. gondii, resulting in a safe product for consumers.

The development of biocompatible hydrogels that allow the controlled release of active components has important applications. In this paper, we report the preparation and characterization of genipin crosslinked chitosan hydrogels loaded with two active components, namely dihydroxyacetone (DHA) or 3-hydroxy-4-trimethylammonium butyrate ( l -carnitine), which are used in cosmetics for skin tanning and antiaging effects, respectively. The rheological properties of these hydrogels, as well as their gelling time were investigated. The oscillatory time sweep method was used to monitor the dynamic viscoelastic parameters during in situ gelation experiments, enabling the determination of the gelation time. On the other hand, the effect of the crosslinker concentration, the concentration of active component loaded, and aging time on the rheological properties of hydrogels was also evaluated. It was found that the presence of DHA prolonged hydrogel gelation, if compared to non-loaded or l -carnitine loaded hydrogels at a constant genipin concentration. The slower gelation process observed for DHA loaded hydrogels was due to the existence of DHA-polymer interactions, demonstrated through NMR and DSC characterization. Finally, DHA and l -carnitine release from crosslinked chitosan hydrogels was measured. The results showed that crosslinked hydrogels produced a retarded and more sustained release, in comparison to aqueous solutions and non-crosslinked hydrogels. Such information could give a clear picture on the potential use of chitosan hydrogels, loaded with either DHA or l -carnitine, as delivery systems for topical application of cosmetic ingredients.

In textile printing, hydrotropic components are usually added to print paste formulations promoting the hydration of textile fabrics by disrupting the hydrogen bonding network between water molecules. For this purpose, urea is commonly used but nevertheless, its presence causes water eutrophication and their reduction or replacement by more environmentally-friendly products is required. In the present work, we have studied an alternative hydrotropic product (polyethylene glycol, PEG) to replace urea. A factorial design of experiments has been carried out to identify the factors that optimize several variables of interest such as viscosity of the printing paste and fabric colour strength. The results showed that a reduction of 70 wt% of urea was achieved by using PEG 400, while preserving the performance of printing formulation. The viscosity of these eco-friendly printing paste formulations was similar to that of the original urea-based formulations and, more interestingly, fabrics showed similar colour strength and fastness to those of fabrics printed by the conventional method., The authors acknowledge financial support from EEA-Grants Program (grant no. 20140916). The authors also greatly acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness (grant no. CTQ2017-84998-P) and support from Generalitat de Catalunya (grant nos. 2017SGR1778 and TECCIT15-1-0009).

This research was partially funded by the Andalucian Operative Program, grant number B-BIO-081-UGR18. All authors have read and agreed to the published version of the manuscript., A 98.1 Kb genomic region from B. pumilus 15.1, a strain isolated as an entomopathogen toward C. capitata, the Mediterranean fruit fly, has been characterised in search of potential virulence factors. The 98.1 Kb region shows a high number of phage-related protein-coding ORFs. Two regions with different phylogenetic origins, one with 28.7 Kb in size, highly conserved in Bacillus strains, and one with 60.2 Kb in size, scarcely found in Bacillus genomes are differentiated. The content of each region is thoroughly characterised using comparative studies. This study demonstrates that these two regions are responsible for the production, after mitomycin induction, of a phage-like particle that packages DNA from the host bacterium and a novel phage for B. pumilus, respectively. Both the phage-like particles and the novel phage are observed and characterised by TEM, and some of their structural proteins are identified by protein fingerprinting. In addition, it is found that the phage-like particle shows bacteriocin activity toward other B. pumilus strains. The effect of the phage-like particles and the phage in the toxicity of the strain toward C. capitata is also evaluated., Andalucian Operative Program B-BIO-081-UGR18

Water-in-Water (W/W) emulsions were prepared in aqueous mixtures of an anionic polyelectrolyte (sodium alginate, NaAlg), with a globular protein (bovine serum albumin, BSA). This combination showed phase separation at two different intervals of pH, and their phase behavior was studied. BSA-in-alginate emulsions were obtained and dropped into Ca2+, Fe3+ or chitosan solutions, forming capsules with diameters around 2–4 mm, by ionic complexation of sodium alginate, located in the continuous phase of the emulsions. The results showed a strong dependence on the cation or polycation. Capsules prepared with Ca2+ were not robust and collapsed during freeze-drying, while Fe3+ induced the gelation of the interior of capsules, even at short (5 min) contact time. Better results were obtained when encapsulating with chitosan and applying longer immersion times. In these capsules, the liquid interior contained well-preserved BSA-in-alginate emulsions droplets, identical to the initial emulsions before encapsulating. Freeze-dried spherical capsules prepared with alginate/Fe3+ or alginate/chitosan shells had smooth surfaces, and a highly porous interior, templated by the presence of W/W emulsion droplets., The present work was mainly financed by the Spanish Ministry of Science and Innovation (CTQ2017S-84998-P), with support from Generalitat de Catalunya (2017SGR1778). In addition, we also acknowledge the “Grupo de Nanotecnología Farmacéutica”, of the Faculty of Pharmacy and Food Sciences, at the University of Barcelona (UB), that forms an R&D Associated Unit (“Unidad Asociada”) to CSIC. J.E also greatly thank Carlos Rodríguez-Abreu (IQAC-CSIC, Barcelona, Spain), Allan Mackie and Josep Bonet (URV, Tarragona, Spain), Maria J. Garcia-Celma (UB, Barcelona, Spain) and Andeaa Pasc (UL, Nancy, France), for useful discussions.

Hybrid inorganic oxides which have simultaneously meso- and macro-porous texture leading to high surface area and high pore volume were prepared by templating in polystyrene monoliths in highly concentrated emulsions. The synthesis was carried out by a two-step method. In the first step, macroporous polystyrene monoliths were prepared using highly concentrated Water-in-Oil (W/O) emulsions as templates, by polymerizing in the external phase of the emulsions. In the second step, the polystyrene monoliths were impregnated with TiO 2 -P 2 O 5 or SiO 2 -TiO 2 -P 2 O 5 sol-gel precursors. Using sol-gel condensation reactions, hybrid inorganic oxide materials were successfully obtained with complex porous structures. The porosity was characterized by electron microscopy (SEM and TEM), and nitrogen sorption. Nitrogen isotherms confirmed that binary TiO 2 -P 2 O 5 hybrid materials were mainly macroporous while ternary hybrid SiO 2 -TiO 2 -P 2 O 5 had all sorts of pores; micropores, mesopores and macropores, with surface area around 300 m 2 /g. Preliminary electrochemical evaluation of these materials has been performed, aiming at possible applications as elements in Proton Exchange Membrane Fuel Cells (PEMFC). Results of conductivity, obtained by Electrochemical Impedance Spectroscopy (EIS) have shown excellent proton conductivity, particularly at low temperatures. Most likely, this is a consequence of high water retention capacity, in small interconnected pores, and acidity provided by P–OH groups on pore surface.

In this work, chitosan hydrogels crosslinked with genipin have been incorporated onto the surface of polyamide fabrics and the porous structure of these modified textiles have been studied. The successful hydrogel incorporation was confirmed by weight gain and evidenced by cryo-SEM. By dynamic vapour sorption (TG-DVS) the water absorption ability of the treated fabrics was studied. The results show that fabrics coated with hydrogel have higher moisture content than uncoated fabric, and they are able to absorb more water at high relative humidity. Also, the pore distribution of fabrics was measured by thermoporometry, which allows the study of pore structures of materials in presence of water. These results show that the hydrogel coating provides new pores smaller than 100 nm, which enhance the water retention.

Epidemiological studies of toxoplasmosis show that infection in humans is mainly caused by the consumption of raw, undercooked or cured meat. Cured “Serrano” ham is a typical pork product from the Mediterranean area, highly valued for its flavour. The “Serrano” ham is prepared from pork meat and undergoes a process known as curing and a subsequent fermentation without thermal or smoking treatments. The viability of Toxoplasma gondii in hams and shoulders from experimentally infected pigs that have been subject to different curing processes has been studied in order to evaluate the best method to completely eliminate the viable protozoa. The different treatments include, i) freezing the legs and shoulders below −20 °C for 3 days before salting with marine salt, ii) salting the meat with marine salt and nitrites, iii) salting only with marine salt (traditional process) and iv) salting with marine salt and then freezing at −20 °C for 3 days after the curing period. The ham leg samples were cured for 7 months and the shoulder samples for 5 months. The presence of T. gondii in the different treatments was studied by a “magnetic-capture” method for the isolation of T. gondii DNA and a quantitative real-time PCR to estimate the T. gondii burden in the ham legs and shoulders. The infectivity capacity of T. gondii in positive samples was assayed by bioassays in mice and some physicochemical parameters, such as pH, water activity (aw) and salt content, were evaluated at the end of the curing time. In all the cases where the samples were frozen the T. gondii infectivity was eliminated. In samples in which the meat was salted in marine salt plus nitrites, the parasite viability remained for longer than in the traditional salting process. The methods described here could be useful for producers to guarantee the safety of their products.

In the present work, the local isolate Bacillus pumilus 15.1 has been morphologically and biochemically characterized in order to gain a better understanding of this novel entomopathogenic strain active against Ceratitis capitata. This strain could represent an interesting biothechnological tool for the control of this pest. Here, we report on its nutrient preferences, extracellular enzyme production, motility mechanism, biofilm production, antibiotic suceptibility, natural resistance to chemical and physical insults, and morphology of the vegetative cells and spores. The pathogen was found to be β-hemolytic and susceptible to penicillin, ampicillin, chloramphenicol, gentamicin, kanamycin, rifampicin, tetracycline, and streptomycin. We also report a series of biocide, thermal, and UV treatments that reduce the viability of B. pumilus 15.1 by several orders of magnitude. Heat and chemical treatments kill at least 99.9 % of vegetative cells, but spores were much more resistant. Bleach was the only chemical that was able to completely eliminate B. pumilus 15.1 spores. Compared to the B. subtilis 168 spores, B. pumilus 15.1 spores were between 2.67 and 350 times more resistant to UV radiation while the vegetative cells of B. pumilus 15.1 were almost up to 3 orders of magnitude more resistant than the model strain. We performed electron microscopy for morphological characterization, and we observed geometric structures resembling the parasporal crystal inclusions synthesized by Bacillus thuringiensis. Some of the results obtained here such as the parasporal inclusion bodies produced by B. pumilus 15.1 could potentially represent virulence factors of this novel and potentially interesting strain.

Previous studies have established that an increased Th-9 response creates a hostile environment for nematode parasites. Given that IL-23, a cytokine required for maintenance of the IL-17–secreting phenotype, has inhibitory effects on IL-9 production, we hypothesized that reducing circulating IL-23 by treatment with anti-IL-23 antibodies would reduce the establishment and development of parasitic intestinal nematodes. In this study, we show that animals treated with anti-IL-23 monoclonal antibodies showed a drastic reduction in the number of mouse pinworms (Aspiculuris tetraptera) recovered from the intestine (p

In this work, highly conductive hybrid organic–inorganic membranes loaded with SiO 2 , TiO 2 –P 2 O 5 and SiO 2 –TiO 2 –P 2 O 5 meso/macroporous particles were prepared via a sol–gel process. Meso/macroporous particles were incorporated to hybrid membranes, for improving water retention and enhancing electrochemical performance. These particles with a polymodal pore size distribution were prepared by templating in highly concentrated emulsions, the particles showed a specific surface area between 50 m 2 /g (TiO 2 –P 2 O 5 ) and 300 m 2 /g (SiO 2 –TiO 2 –P 2 O 5 ). The particles were dispersed in a hybrid silica sol and further sprayed onto glass paper. The films were polymerized and sintered; those loaded with meso/macroporous particles had a homogenous distribution. High temperature proton conductivity measurements confirmed a high water retention. Conductivity of these materials is higher than that of Nafion ® at higher temperatures (120 °C) (2·10 −2 S/cm). This study provides processing guideline to achieve hybrid electrolytes for efficient conduction of protons due to their high surface area and porous structure.

Emulsion templating is an effective route for the preparation of macroporous polymer foams, with well-defined pore structures. This kind of material is usually obtained by polymerization or crosslinking in the external phase of highly concentrated emulsions. The present article describes the synthesis of macroporous foams based on a cationic polymer, chitosan, crosslinked with genipin, a natural crosslinker. The phase behavior was used to study the influence of chitosan on surfactant self-aggregation. Hexagonal and lamellar liquid crystalline structures could be obtained in the presence of chitosan, and polymer did not greatly influence the geometric lattice parameters of these self-aggregates. O/W highly concentrated emulsions were obtained in the presence of chitosan in the continuous phase, which allowed reducing both droplet size and polydispersity. The emulsions were stable during the time required for crosslinking, obtaining macroporous foams with high pore volume and degree of crosslinking.

The insecticidal Cry toxins produced by Bacillus thuringiensis (Bt) are increasingly important in the biological control of insect pests and vectors of human disease. Markets for Bt products and transgenic plants expressing their toxins are driven by their specificity, safety and the move away from chemical control agents. However, the high specificity of Cry toxins can also prove to be a limitation when there is no known Cry toxin active against a particular target. Novel activities can be discovered by screening natural Bt isolates or through modifications of the Cry proteins. Here we demonstrate the use of λ-phage displaying Cry1Aa13 toxin variants modified in domain II loop 2 (Crybodies) to select retargeted toxins. Through biopanning using gut tissue from larvae of the non-target insect Aedes aegypti, we isolated a number of phage for further testing. Two of the overexpressed Cry toxin variants showed significant activity against A. aegypti larvae while another induced mortality at the pupal stage. We present the first report of the use of phage display to identify novel activities toward insects from distant taxonomic Orders and establish this technology based on the use of Crybodies as a powerful tool for developing tailor-made insecticides against new target insects.

Bacillus pumilus strain 15.1 was previously found to cause larval mortality in the Med-fly 27 Ceratitis capitata and was shown to produce crystals in association with the spore. As 28 parasporal crystals are well-known as invertebrate-active toxins in entomopathogenic 29 bacteria such as Bacillus thuringiensis (Cry and Cyt toxins) and Lysinibacillus sphaericus (Bin 30 and Cry toxins), the B. pumilus crystals were characterised. The crystals were composed of a 31 45 kDa protein that was identified as an oxalate decarboxylase by peptide mass 32 fingerprinting, N-terminal sequencing and by comparison with the genome sequence of strain 33 15.1. Synthesis of crystals by a plasmid-cured derivative of strain 15.1 (produced using a 34 novel curing strategy), demonstrated that the oxalate decarboxylase was encoded 35 chromosomally. Crystals spontaneously solubilized when kept at low temperatures and the 36 protein produced was resistant to trypsin treatment. The insoluble crystals produced by 37 B. pumilus 15.1 did not show significant toxicity when bioassayed against C. capitata larvae, 38 but once the OxdD protein was solubilized, an increase of toxicity was observed. We also 39 demonstrate that the OxdD present in the crystals has oxalate decarboxylate activity as the 40 formation of formate was detected, which suggests a possible mechanism for B. pumilus 15.1 41 activity. To our knowledge, the characterization of the B. pumilus crystals as oxalate 42 decarboxylase is the first report of the natural production of parasporal inclusions of an 43 enzyme.

New oil-in-alcohol highly concentrated emulsions were formulated and were used as a templates to obtain macroporous poly(furfuryl alcohol) monoliths by a one-step method. The oil-in-alcohol highly concentrated emulsions were prepared by stepwise addition of the oil phase to the surfactant-alcohol solution and were characterized by optical microscopy and by laser diffraction. The typical structure of highly concentrated emulsions, with close-packed polyhedral droplets, has been observed. Poly(furfuryl alcohol) monoliths were obtained by polymerizing in the external phase of these emulsions. These materials are mainly macroporous and retain the size distribution and morphology from the highly concentrated emulsions. The internal structure of the monoliths was observed by scanning electron microscopy. The images showed an interconnected network with pore size similar to the droplet size of the highly concentrated emulsions used as templates.

Plant growth-promoting rhizobacteria (PGPR) increase the viability and health of host plants when they colonize roots and engage in associative symbiosis (Bashan et al. 2004). In return, PGPR viability is increased by host plant roots by the provision of nutrients and a more protective environment (Richardson et al. in Plant Soil 321:305-339, 2009). The PGPR have great potential in agriculture since the combination of certain microorganisms and plants can increase crop production and increase protection against frost, salinity, drought and other environmental stresses such as the presence of xenobiotic pollutants. But there is a great challenge in combining plants and microorganisms without compromising the viability of either microorganisms or seeds. In this paper, we review how anhydrobiotic engineering can be used for the formulation of biotechnological tools that guarantee the supply of both plants and microorganisms in the dry state. We also describe the application of this technology for the selection of desiccation-tolerant PGPR for polycyclic aromatic hydrocarbons bioremediation, in soils subjected to seasonal drought, by the rhizoremediation process.

Textile processes generally produce a large amount of wastewater and cause a negative environmental impact. The use of proteases in wool finishing could be an appropriate alternative to classical finishing methods. However, the enzymatic treatment could cause excessive fiber damage. The application of biopolymer chitosan on wool fabrics prior to proteases treatment in attempt to overcome the damage promoted by the enzymes has been studied. The treatments based on chitosan application followed by enzymatic treatment reduce felting shrinkage, enhance whiteness degree, and improve dyeability of wool. Moreover, it plays an important role in minimizing the wool fiber damage.

We present the draft whole-genome sequence of the entomopathogenic Bacillus pumilus 15.1 strain that consists of 3,795,691 bp and 3,776 predicted protein-coding genes. This genome sequence provides the basis for understanding the potential mechanism behind the toxicity and virulence of B. pumilus 15.1 against the Mediterranean fruit fly. Fil: García Ramón, Diana Carolina. Universidad de Granada; España Fil: Palma, Leopoldo. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina Fil: Berry, Colin. Cardiff University; Reino Unido Fil: Osuna, Antonio. Universidad de Granada; España Fil: Vilchez, Susana. Universidad de Granada; España

The Bacillus pumilus 15.1 strain, a recently described entomopathogenic strain active against Ceratitis capitata, contains at least two extrachromosomal elements, pBp15.1S and pBp15.1B. Given that B. pumilus is not a typical entomopathogenic bacterium, the acquisition of this extrachromosomal DNA may explain why B. pumilus 15.1 is toxic to an insect. One of the plasmids present in the strain, the pBp15.1S plasmid, was sub-cloned, sequenced and analyzed using bioinformatics to identify any potential virulence factor. The pBp15.1S plasmid was found to be 7785 bp in size with a GC content of 35.7% and 11 putative ORFs. A replication module typical of a small rolling circle plasmid and a sensing and regulatory system specific for plasmids was found in pBp15.1S. Additionally, we demonstrated the existence of ssDNA in plasmid preparations suggesting that pBp15.1S replicates by the small rolling circle mechanism. A gene cluster present in plasmid pPZZ84 from a distantly isolated B. pumilus strain was also present in pBp15.1S. The plasmid copy number of pBp15.1S in exponentially growing B. pumilus cells was determined to be 33 copies per chromosome. After an extensive plasmid characterization, no known virulence factor was found so a search in the other extrachromosomal elements of the bacteria is needed.

A homologue of the Bacillus subtilis fur gene was identified in Bacillus cereus and characterized. The predicted amino acid sequence of the cloned gene was found to be highly similar to other members of the Fur family of transcriptional regulators. The B. cereus fur gene was shown to partially complement an Escherichia coli fur mutant. Purified B. cereus Fur bound specifically to a 19 bp DNA sequence homologous to the B. subtilis Fur box in a metal-dependent manner. Analysis of the available B. cereus genome data identified a number of genes which contain predicted Fur box sequences in the promoter region. Many of these genes are predicted to play a role in bacterial iron uptake and metabolism, but several have also been implicated as having a role in virulence. Fur and iron regulation of a siderophore biosynthesis operon was confirmed in a β-galactosidase assay. A B. cereus fur null strain was constructed by allelic replacement of the chromosomal gene with a copy disrupted with a kanamycin resistance cassette. The Δfur mutant was found to constitutively express siderophores, to accumulate iron intracellularly to a level approximately threefold greater than the wild-type, and to be hypersensitive to hydrogen peroxide. In an insect infection model, the virulence of the fur null strain was found to be significantly attenuated, highlighting the essential role played by Fur in the virulence of this pathogen.

The tetrahydropyramidine hydroxyectoine acts as an osmolyte in a range of bacterial species, but its use as a desiccation protectant is less well explored. Recently, it was demonstrated that hydroxyectoine provides effective stabilisation of the Gram-negative species Pseudomonas putida, which is only relatively poorly preserved by the better-characterised protectant, trehalose. It is now shown that hydroxyectoine also protects the paradigmatic bacterium, Escherichia coli: osmotically-preconditioned E. coli dried in hydroxyectoine exhibited a high degree of desiccation tolerance, similar to that achieved using trehalose in this species. Hydroxyectoine is apparently accumulated from hypersaline medium in preference to trehalose biosynthesis, but E. coli loaded with hydroxyectoine in this way showed reduced stability in the dry state. This suggests that, although both hydroxyectoine and trehalose perform equally well as extracellular protectants, trehalose is preferred for intracellular protection.

This work describes the construction of the rhizobacterium Pseudomonas putida strain CS-4, which contains an active biological containment (ABC) system that ensures bacterial suicide in the absence of proline. Maize plants exudate proline, which allows CS-4 to colonize the rhizosphere at a similar level to that of the wild-type strain. However, when the plants are removed, the CS-4 population decreased in bulk soil at a higher rate than the wild-type strain.

Kin selection could provide an explanation for social behavior in bacteria. The production of public goods such as extracellular molecules is metabolically costly for bacteria but could help them to exploit nutrients or invade a host. Some bacterial cells called social cheaters do not produce public goods; however, they take advantage of these extracellular molecules. In this review, the relationships between social behavior, cooperation, and evolution of bacterial pathogenicity are analyzed. This paper also examines the role of horizontal transfer of genes encoding for virulence factors and how the movement of mobile genetic elements would influence the pathogenicity and social relationships. Moreover, the link between ecological relationships and evolution in entomopathogenic bacteria, focusing on Bacillus thuringiensis is considered. Finally, the findings obtained with B. thuringiensis are extrapolated on Bacillus pumilus 15.1, an entomopathogenic strain whose pathogenicity is not understood yet.

"Serrano" ham is a typical pork product from the Mediterranean area, highly valued for its flavour. To make Serrano ham, pork undergoes a salting and a subsequent fermentation process known as curing. Certain pigs used for meat production are an important source of Toxoplasma gondii infection in humans. We have developed a method for quantifying and assaying the viability of the T. gondii present in commercial Serrano ham samples. A magnetic capture method for the isolation of T. gondii DNA and a qRT-PCR were used to estimate the T. gondii burden in 475 commercial samples of "Serrano" ham in two presentation formats: ham pieces and sliced ham. The infectivity capacity of T. gondii in positive samples was assayed in mice. The global prevalence of T. gondii was 8.84%, ranging from 32.35% in one of the companies to 0% prevalence in three other companies. The infectivity assays revealed that only 4.84% of the positive samples were infective. To the best of our knowledge this is the first report focussing on the prevalence of T. gondii in commercial "Serrano" ham. The method described here could be useful for producers to guarantee the safety of their products.

Pseudomonas putida KT2440 uses proline as the sole C and N source. Utilization of this amino acid involves its uptake, which is mediated by the PutP protein, and its conversion into glutamate, mediated by the PutA protein. Sequence analysis revealed that the putA and putP genes are transcribed divergently. Expression from the putP and putA genes was analyzed at the mRNA level in different host backgrounds in the absence and presence of proline. Expression from the put promoters was induced by proline. The transcription initiation points of the putP and putA genes were precisely mapped via primer extension, and sequence analysis of the upstream DNA region showed well-separated promoters for these two genes. The PutA protein acts as a repressor of put gene expression in P. putida because expression from the put promoters is constitutive in a host background with a knockout putA gene. This regulatory activity is independent of the catabolic activity of PutA, because we show that a point mutation (Glu896→Lys) that prevents catalytic activity allowed the protein to retain its regulatory activity. Expression from the put promoters in the presence of proline in a putA -proficient background requires a positive regulatory protein, still unidentified, whose expression seems to be ς 54 dependent because the put genes were not expressed in a ς 54 -deficient background. Expression of the putA and putP genes was equally high in the presence of proline in ς 38 - and ihf -deficient P. putida backgrounds.

This work reports on the feasibility of atmospheric dielectric barrier discharge (DBD) plasma as a novel synthetic pathway for the liquid phase gelation of chitosan. The DBD plasma chitosan gelation process did not significantly alter the chemical structure of the biopolymer as confirmed by FTIR study. However, the oxidation processes and local heating effect associated with the solvent evaporation during the plasma treatment could provoke both reaction of chitosan degradation and the cleavage of β-1-4-glycosidic linkages with the concomitant generation of aldehyde groups able to crosslink via Schiff-base with amino groups from other chitosan molecules. Shear viscosity measurements suggested the formation of chitosan fragments of lower molecular weight after the plasma treatment of 1% (w/v) chitosan and fragments of higher molecular weight after the plasma treatment of 2% (w/v) chitosan. The crosslinking density of hydrogels generated during the in situ DBD plasma chitosan gelation process increased as a function of the treatment time and concentration of chitosan. As of consequence of the increase of the cross-linking density, the equilibrium swelling ratio and water content decreased significantly.

Knowledge of the mechanisms of interaction between self-aggregating peptides and nucleic acids or other polyanions is key to the understanding of many aggregation processes underlying several human diseases (e.g. Alzheimer's and Parkinson's diseases). Determining the affinity and kinetic steps of such interactions is challenging due to the competition between hydrophobic self-aggregating forces and electrostatic binding forces. Kahalalide F (KF) is an anticancer hydrophobic peptide which contains a single positive charge that confers strong aggregative properties with polyanions. This makes KF an ideal model to elucidate the mechanisms by which self-aggregation competes with binding to a strongly charged polyelectrolyte such as DNA. We use optical tweezers to apply mechanical forces to single DNA molecules and show that KF and DNA interact in a two-step kinetic process promoted by the electrostatic binding of DNA to the aggregate surface followed by the stabilization of the complex due to hydrophobic interactions. From the measured pulling curves we determine the spectrum of binding affinities, kinetic barriers and lengths of DNA segments sequestered within the KF-DNA complex. We find there is a capture distance beyond which the complex collapses into compact aggregates stabilized by strong hydrophobic forces, and discuss how the bending rigidity of the nucleic acid affects such process. We hypothesize that within an in vivo context, the enhanced electrostatic interaction of KF due to its aggregation might mediate the binding to other polyanions. The proposed methodology should be useful to quantitatively characterize other compounds or proteins in which the formation of aggregates is relevant., Comment: 34 pages, 8 figures, Supplementary Information

Escherichia coli and Pseudomonas putida dried in hydroxyectoine or trehalose are shown to be highly resistant to the organic solvents chloroform and acetone, and consequently, they can be encapsulated in a viable form in solid plastic materials. Bacteria are recovered by rehydration after physical disruption of the plastic. P. putida incorporated into a plastic coating of maize seeds was shown to colonize roots efficiently after germination.

Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), the Mediterranean fruit fly (medfly), is one of the most important fruit pests worldwide. The medfly is a polyphagous species that causes losses in many crops, which leads to huge economic losses. Entomopathogenic bacteria belonging to the genus Bacillus have been proven to be safe, environmentally friendly, and cost-effective tools to control pest populations. As no control method for C. capitata based on these bacteria has been developed, isolation of novel strains is needed. Here, we report the isolation of 115 bacterial strains and the results of toxicity screening with adults and larvae of C. capitata . As a result of this analysis, we obtained a novel Bacillus pumilus strain, strain 15.1, that is highly toxic to C. capitata larvae. The toxicity of this strain for C. capitata was related to the sporulation process and was observed only when cultures were incubated at low temperatures before they were used in a bioassay. The mortality rate for C. capitata larvae ranged from 68 to 94% depending on the conditions under which the culture was kept before the bioassay. Toxicity was proven to be a special characteristic of the newly isolated strain, since other B. pumilus strains did not have a toxic effect on C. capitata larvae. The results of the present study suggest that B. pumilus 15.1 could be considered a strong candidate for developing strategies for biological control of C. capitata .

At least two types of Wolbachia bacteria were detected in wild and insectarium-raised Rhodnius pallescens , a natural vector of Trypanosoma cruzi and Trypanosoma rangeli. Wolbachia was detected in all the organs and tissues studied and in the feces, and this provided a methodological advantage for determining the presence of this endosymbiont in this host, obviating the need to kill the specimens. The occurrence of trypanosomatids in wild individuals was also studied.

In the xenodiagnosis (XD) of American trypanosomiasis (Chagas disease), Trypanosoma cruzi in the triatomine bugs fed on the patient can now be detected using PCR (XD-PCR) as well as by microscopy (XD-M). In a study to compare XD-PCR with XD-M, triatomine bugs were fed on 50 cases of chronic American trypanosomiasis, of whom only 25 were ever found positive by XD-M. Overall, the bugs fed on 34 of the patients (all 25 cases found positive by XD-M and nine of the other patients) were found PCR-positive, giving a 330-bp fragment corresponding to part of the hyper variable region of the kinetoplast DNA of T. cruzi. Of the 25 patients who were ever found positive by XD-M, 20 gave bugs that were smear-positive on day 90 and a similar number (24; P=0.125) gave bugs that were PCR-positive at this time. On day 30, however, the bugs fed on only 11 of these 25 patients were found positive by microscopy, whereas 23 of these patients were found positive by XD-PCR (P=0.0016). Thus, not only was XD-PCR more sensitive than XD-M but it was also quicker, revealing more cases within 30 days than detected using XD-M over a period of 90 days.

Pseudomonas putida dried in the presence of hydroxyectoine or trehalose can withstand exposure to organic solvents and therefore can be encapsulated inside plastics such as polystyrene. Here we show that P. putida in a plastic-encapsulated dried tablet exhibits remarkable tolerance to chemical stress, comparable to that of spores of Bacillus subtilis.

5 pages, 4 figures, 2 tables.-- Available online Jan 11, 2006., There is a difference in structure across the wool fibre which is usually referred to as bilateral. The endothermic denaturation doublet of keratins has been observed by different authors for a variety of keratins and measuring conditions and mainly interpreted by different theories. Merino wool yarns have been analyzed by the thermomechanical analysis and at low stress two thermal transitions before melting have been identified. These two thermal transitions are in accordance with the onset temperatures of the denaturation doublet shown by the DSC both at temperatures lower than the thermal degradation temperature determined by TG. The DSC of fibrillated fibres by abrasion showed not a denaturation doublet but just only a denaturation peak. The two transitions of the TMA and the modification of the DSC curve by abrasion seems to confirm that abrasion removes the component which denaturates at lower temperature., Authors are indebted the Spanish Ministry of Science and Education for its financial help through the Project MAT2004-04981-C03-03.

11 pages, 8 figures, 4 tables.-- Printed version published Sep 15, 2005., This study examines in detail the influence of low-temperature plasma and biopolymer chitosan treatments on wool dyeability. Wool knitted fabrics were treated and characterized by whiteness and shrink-resistance measurements. Surface modification was assessed by contact-angle measurements of human hair fibers, which were used as a model to study the wetting properties of the treated wool knitted fabrics. The dyeing behavior was assessed from the diffusion mechanism point of view. The dyeing kinetics were measured at two different pHs (4.2 and 6.5) and three different temperatures (60, 85, and 100ºC) to gain information about the contribution of the surface modification treatment to the dyeing mechanism. The exhaustion and reflectance data were compared, and the apparent diffusion coefficients were calculated. On the basis of the obtained results, a model for the dyeing mechanism of the chitosan treated wool was proposed. When treated with chitosan, the polymer sheath spread on the surface of the fibers acted as a predominant dyeing site in very short dyeing times, thus interacting with the dye and in later stages imparting the dye to the wool fiber., The authors are grateful for the support of the Spanish Ministry of Education and Culture, which financed the sabbatical stay of one of the of the authors (D.J.) in Instituto de Investigaciones Químicas y Ambientales de Barcelona, Consejo Superior de Investigaciones Científicas (IIQAB-CSIC).

9 pges, 8 figures, 4 tables.-- Printed version published Dec 5, 2005., The influence of a chitosan application on wool fabric before a treatment with a proteolytic enzyme has been investigated. The enzymatic treatment enhances whiteness and confers shrink resistance to wool, but an increase in the enzyme concentration leads to a detrimental effect on the physicomechanical properties. A chitosan treatment before the enzymatic treatment additionally improves the shrink resistance and increases the weight loss. To better investigate the role played by the chitosan, surface-related properties, such as the friction coefficient, the compressional behavior (compressibility, linearity of compression, and thickness), the wearing resistance (weight loss after abrasion), the bursting resistance (bursting strength and deformation), and surface topography, have been studied. The results suggest that the chitosan pretreatment reduces the damage caused by the subsequent enzymatic treatment. They also imply a protective effect of the bursting and wearing resistance, which prevent excessive weight loss due to abrasion. A significant influence of the wool fiber cell membrane complex on the surface-related properties has been demonstrated through regression analysis and scanning electron microscopy observations.

9 pages, 4 figures, 3 tables.-- Available online Dec 18, 2004., This study assesses the interactions that could occur during dyeing of the chitosan treated wool fibres on basis of the spectrophotometric study, by measuring the absorbance values of the solutions containing dye and chitosan. It has been shown that there is a 1:1 stoichiometry between protonated amino groups and sulfonate acid groups on the dye ions in low concentrated chitosan solutions. This interaction forms an insoluble chitosan/dye product. With the excess of chitosan in the solution, the dye can be distributed between the different chitosan molecules and the soluble chitosan/dye products remain in the solution. The mechanism of the interaction is suggested, that involves the possibility of adsorbed dye molecules to be desorbed and redistributed between other components present in the system, depending on system parameters (pH, temperature and electrolyte presence). This fact is important in explanation of dyeing behaviour of chitosan treated wool and enables the assessment of the mechanism of dyeing of accordingly modified textile fibres.

The successful use of Bacillus thuringiensis insecticidal toxins to control agricultural pests could be undermined by the evolution of insect resistance. Under selection pressure in the laboratory, a number of insects have gained resistance to the toxins, and several cases of resistance in the diamondback moth have been reported from the field. The use of protein engineering to develop novel toxins active against resistant insects could offer a solution to this problem. The display of proteins on the surface of phages has been shown to be a powerful technology to search for proteins with new characteristics from combinatorial libraries. However, this potential of phage display to develop Cry toxins with new binding properties and new target specificities has hitherto not been realized because of the failure of displayed Cry toxins to bind their natural receptors. In this work we describe the construction of a display system in which the Cry1Ac toxin is fused to the amino terminus of the capsid protein D of bacteriophage lambda. The resultant phage was viable and infectious, and the displayed toxin interacted successfully with its natural receptor.

This work describes the construction of the rhizobacterium Pseudomonas putida strain CS-4, which contains an active biological containment (ABC) system that ensures bacterial suicide in the absence of proline. Maize plants exudate proline, which allows CS-4 to colonize the rhizosphere at a similar level to that of the wild-type strain. However, when the plants are removed, the CS-4 population decreased in bulk soil at a higher rate than the wild-type strain.