The Use of Spider Webs as Passive Bioaerosol Collectors

In this experiment, spider webs demonstrated their suitability as passive bioaerosol collectors. For spider webs to be considered suitable passive collectors webs had to satisfy three basic conditions; (1) collection of microorganisms without discrimination based on species or size, (2) collection under variable environmental conditions, and (3) saturation avoidance in the presence of strong microbial launching sources. Four field sampling locations were used, a waste water treatment facility, a commercial garden center, a secluded state park area, and a parking garage. Microscopy cover glass slides were used as the collection instrument. The methodology assured sterility during collection and promoted in situ microbial growth and observation which were important aspects in this study. All collected spider webs revealed microbial growth from both bacteria and fungi species. This experiment paved the way for future use of webs as passive collectors of biological warfare agents and chemical warfare agents

Intracellular targeting and functional analysis of single-chain Fv fragments in mammalian cells

In the past decade, intracellular antibodies have proven to be a useful tool in obtaining the phenotypic knock-out of selected gene function in different animal and plant systems. This strategy is based on the ectopic expression of recombinant forms of antibodies targeted towards different intracellular compartments, exploiting specific targeting signals to confer the new intracellular location. The functional basis of this technology is closely linked to the ability of intracellular antibodies to interact with their target antigens in vivo. This interaction allows either a direct neutralising effect or the dislodgement of the target protein from its normal intracellular location and, by this mechanism, the inactivation of its function. By using this approach, the function of several antigens has been inhibited in the cytoplasm, the nucleus, and the secretory compartments. In this article, we shall describe all the steps required for expressing single-chain Fv fragments in different subcellular compartments of mammalian cells and their subsequent use in knock-out experiments, starting from a cloned single-chain Fv fragment. This will include the analysis of the solubility properties of the new scFv fragment in transfected mammalian cells, the intracellular distribution of the antigen-antibody complex, and the resulting phenotype

Loss of correlation between HIV viral load and CD4+ T-cell counts in HIV/HTLV-1 co-infection in treatment naive Mozambican patients

Seven hundred and four HIV-1/2-positive, antiretroviral therapy (ART) naïve patients were screened for HTLV-1 infection. Antibodies to HTLV-1 were found in 32/704 (4.5%) of the patients. Each co-infected individual was matched with two HIV mono-infected patients according to World Health Organization clinical stage, age +/-5 years and gender. Key clinical and laboratory characteristics were compared between the two groups. Mono-infected and co-infected patients displayed similar clinical characteristics. However, co-infected patients had higher absolute CD4+ T-cell counts (P = 0.001), higher percentage CD4+ T-cell counts (P < 0.001) and higher CD4/CD8 ratios (P < 0.001). Although HIV plasma RNA viral loads were inversely correlated with CD4+ T-cell-counts in mono-infected patients (P < 0.0001), a correlation was not found in co-infected individuals (P = 0.11). Patients with untreated HIV and HTLV-1 co-infection show a dissociation between immunological and HIV virological markers. Current recommendations for initiating ART and chemoprophylaxis against opportunistic infections in resource-poor settings rely on more readily available CD4+ T-cell counts without viral load parameters. These guidelines are not appropriate for co-infected individuals in whom high CD4+ T-cell counts persist despite high HIV viral load states. Thus, for co-infected patients, even in resource-poor settings, HIV viral loads are likely to contribute information crucial for the appropriate timing of ART introduction

Differential effects on membrane permeability and viability of human keratinocyte cells undergoing very low intensity megasonic fields

Among different therapeutic applications of Ultrasound (US), transient membrane sonoporation (SP) - a temporary, non-lethal porosity, mechanically induced in cell membranes through US exposure - represents a compelling opportunity towards an efficient and safe drug delivery. Nevertheless, progresses in this field have been limited by an insufficient understanding of the potential cytotoxic effects of US related to the failure of the cellular repair and to the possible activation of inflammatory pathway. In this framework we studied the in vitro effects of very low-intensity US on a human keratinocyte cell line, which represents an ideal model system of skin protective barrier cells which are the first to be involved during medical US treatments. Bioeffects linked to US application at 1 MHz varying the exposure parameters were investigated by fluorescence microscopy and fluorescence activated cell sorting. Our results indicate that keratinocytes undergoing low US doses can uptake drug model molecules with size and efficiency which depend on exposure parameters. According to sub-cavitation SP models, we have identified the range of doses triggering transient membrane SP, actually with negligible biological damage. By increasing US doses we observed a reduced cells viability and an inflammatory gene overexpression enlightening novel healthy relevant strategies

Decentralized Triangular Guidance Algorithms for Formations of UAVs

This paper deals with the design of a guidance control system for a swarm of unmanned aerial systems flying at a given altitude, addressing flight formation requirements that can be formulated constraining the swarm to be on the nodes of a triangular mesh. Three decentralized guidance algorithms are presented. A classical fixed leader–follower scheme is compared with two alternative schemes: the former is based on the self-identification of one or more time-varying leaders; the latter is an algorithm without leaders. Several operational scenarios have been simulated involving swarms with obstacles and an increasing number of aircraft in order to prove the effectiveness of the proposed guidance schem

Isolation and characterization of oxidizedoligogalacturonides: meccanism of dampening of damps

Oligogalacturonides (OGs) released upon partial degradation of homogalacturonan, are a well-known class of Damage-Associated Molecular Patterns (DAMPs). Besides inducing immunity, OGs negatively affect plant growth by antagonizing auxin responses. Because the recognition of DAMPs poses the intrinsic risk of activating an exaggerated response that may impair plant survival, dampening mechanisms of DAMPs should exist. Transgenic Arabidopsis plants (OGM plants) expressing a chimeric protein called "OGmachine" accumulate oligogalacturonides (OGs) in their tissues and exhibit enhanced resistance to a variety of pathogens; however the growth of these plants is severely impaired. The prolonged release of OGs triggers defense responses that in the long term are deleterious for the plant. We used the OGM plants as a tool to investigate a possible regulatory mechanism by searching for elicitor-inactive OGs that may derive from elicitor-active OGs through an enzymatic modification. By analyzing the OGs produced in the transgenic plants, modified OGs were isolated. The nature of the modification was investigated by electrospray ionization mass spectrometry and resulted to be the oxidation to galactaric acid of the residue at the reducing end of OGs (oxOGs). OxOGs were tested for their ability to induce defense responses and antagonize auxin responses. In all experiments, they were inactive as compared to the corresponding typical OGs. We succeeded to isolate and characterize one of the enzymes that causes the inactivation of OGs: it is a FAD binding oxidase, that we named OGOX1, capable of producing elicitor-inactive oxidized OGs and H2O2