Synthesis of gold nanoparticles using Crinum macowanii bulb extracts and the application of these materials in blood detections at crime scenes

We here in report the synthesis of gold nanoparticles (AuNPs) using a Crinum macowanii bulb water extract. The as‐synthesized AuNPs were characterized using ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, and a zeta potential‐sizer. The results showed that the as‐synthesized AuNPs were crystalline and mostly spherical in shape with a small mixture of triangular, tetrahedral, hexagonal, octagonal, and diamond shapes. The as‐synthesized AuNPs together with those synthesized by conventional methods were subsequently used as enhancers for the luminol signal in blood detection. It was noted that the AuNPs synthesized from the Crinum macowanii bulb water extract could enhance the chemiluminescence signal for blood detection by luminol to the same extent as AuNPs prepared by conventional methods. Furthermore, both types of AuNPs served as fluorescence enhancers for blood detection when luminol was replaced with the bulb water extract.     

Differential assembly of polypeptides of the light-harvesting 2 complex encoded by distinct operons during acclimation of Rhodobacter sphaeroides to low light intensity

In order to obtain an improved understanding of the assembly of the bacterial photosynthetic apparatus, we have conducted a proteomic analysis of pigment-protein complexes isolated from the purple bacterium Rhodobacter sphaeroides undergoing acclimation to reduced incident light intensity. Photoheterotrophically growing cells were shifted from 1,100 to 100?W/m(2) and intracytoplasmic membrane (ICM) vesicles isolated over 24-h were subjected to clear native polyacrylamide gel electrophoresis. Bands containing the LH2 and reaction center (RC)-LH1 complexes were excised and subjected to in-gel trypsin digestion followed by liquid chromatography (LC)-mass spectroscopy (MS)/MS. The results revealed that the LH2 band contained distinct levels of the LH2-α and -β polypeptides encoded by the two puc operons. Polypeptide subunits encoded by the puc2AB operon predominated under high light and in the early stages of acclimation to low light, while after 24?h, the puc1BAC components were most abundant. Surprisingly, the Puc2A polypeptide containing a 251 residue C-terminal extension not present in Puc1A, was a protein of major abundance. A predominance of Puc2A components in the LH2 complex formed at high light intensity is followed by a >2.5-fold enrichment in Puc1B levels between 3 and 24?h of acclimation, accompanied by a nearly twofold decrease in Puc2A levels. This indicates that the puc1BAC operon is under more stringent light control, thought to reflect differences in the puc1 upstream regulatory region. In contrast, elevated levels of Puc2 polypeptides were seen 48?h after the gratuitous induction of ICM formation at low aeration in the dark, while after 24?h of acclimation to low light, an absence of alterations in Puc polypeptide distributions was observed in the upper LH2-enriched gel band, despite an approximate twofold increase in overall LH2 levels. This is consistent with the origin of this band from a pool of LH2 laid down early in development that is distinct from subsequently assembled LH2-only domains, forming the LH2 gel band.     

Autoregulation of RCO by Low-Affinity Binding Modulates Cytokinin Action and Shapes Leaf Diversity

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Integrating phylogenetic community structure with species distribution models: an example with plants of rock barrens

Approaches using phylogenetic pattern in ecological communities to deduce processes of community assembly have been criticised as disconnected from foundations in ecological mechanism, especially with respect to lack of data about abiotic and biotic niches. These criticisms can be addressed with analyses of organismal traits that underlie environmental filtering, competitive exclusion, and other candidate processes; however, the difficulty of assembling large trait databases means that such studies remain uncommon. We suggest a synthesis of phylogenetic community structure analysis and species distribution modeling that we believe can allow inference about community processes without prohibitive data requirements. We illustrate this method for angiosperm communities of rock barrens in eastern Canada. First, we analyzed phylogenetic community structure of four rock‐barren sites at three nested spatial scales (quadrat to region). For the nine most common species in our barrens, we used regional occurrence records to build species distribution models identifying environmental drivers of the nine species’ distributions. Coefficients of these models represent implicit trait data that summarize each species’ response to the environmental drivers in the model. We then tested for phylogenetic signal in these traits, to ask whether ecological forces acting on them could be generating phylogenetic community structure. We found strong phylogenetic clustering at the quadrat level, while patterns at larger scales were complex. Our distribution model suggested drought stress as the dominant driver for distributions of all the species, consistent with local correlations with soil depth, and the species’ responses to drought showed strong phylogenetic signal. The convergence of results from phylogenetic community structure and species distribution modeling suggests that barren communities are structured at the quadrat level by environmental filtering effects of moisture stress, to which species have phylogenetically patterned responses.     

Green synthesis of silver nanoparticles using cellulose extracted from an aquatic weed; water hyacinth

As part of the desire to save the environment through “green” chemistry practices, we herein report an environmentally benign synthesis of silver nanoparticles (Ag-NPs) using cellulose extracted from an environmentally problematic aquatic weed, water hyacinth (WH), as both reducing and capping agent in an aqueous medium. By varying the pH of the solution and reaction time, the temporal evolutions of the optical and morphological properties of the as-synthesised Ag-NPs were investigated. The as-synthesised cellulose capped silver nanoparticles (C–Ag-NPs) were characterised using Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The maximum surface plasmon resonance (SPR) peak decreased as the pH increased indicating that an increase in the pH of the solution favoured the formation of smaller particles. In addition, instantaneous change in the colour of the solution from colourless to brown within 5 min at pH 11 showed that the rate of reduction is faster at this pH compared to those at lower pH. The TEM micrographs showed that the materials are small, highly monodispersed and spherical in shape. The average particle mean diameters were calculated to be 5.69 ± 5.89 nm, 4.53 ± 1.36 nm and 2.68 ± 0.69 nm nm at pH 4, 8 and 11 respectively. The HRTEM confirmed the crystallinity of the material while the FTIR spectra confirmed the capping of the as-synthesised Ag-NPs by the cellulose. It has been shown therefore that based on this synthetic method, this aquatic plant can be used to the advantage of mankind.     

Aminopeptidase substrate preference affects HIV epitope presentation and predicts immune escape patterns in HIV-infected individuals

Viruses evade immune detection partly through immune-associated mutations. Analyses of HIV sequences derived from infected individuals have identified numerous examples of HLA-associated mutations within or adjacent to T cell epitopes, but the potential impact of most mutations on epitope production and presentation remains unclear. The multistep breakdown of proteins into epitopes includes trimming of N-extended peptides into epitopes by aminopeptidases before loading onto MHC class I molecules. Definition of sequence signatures that modulate epitope production would lead to a better understanding of factors driving viral evolution and immune escape at the population level. In this study, we identified cytosolic aminopeptidases cleavage preferences in primary cells and its impact on HIV Ag degradation into epitopes in primary human cell extracts by mass spectrometry and on epitope presentation to CTL. We observed a hierarchy of preferred amino acid cleavage by cytosolic aminopeptidases. We demonstrated that flanking mutations producing more or less cleavable motifs can increase or decrease epitope production and presentation by up to 14-fold. We found that the efficiency of epitope production correlates with cleavability of flanking residues. These in vitro findings were supported by in vivo population-level analyses of clinically derived viral sequences from 1134 antiretroviral-naive HIV-infected individuals: HLA-associated mutations immune pressures drove the selection of residues that are less cleavable by aminopeptidases predominantly at N-flanking sites, leading to reduced epitope production and immune recognition. These results underscore an important and widespread role of Ag processing mutations in HIV immune escape and identify molecular mechanisms underlying impaired epitope presentation.     

Characterization of Heterotopic Ossification Using Radiographic Imaging: Evidence for a Paradigm Shift

Heterotopic ossification (HO) is the growth of extra-skeletal bone which occurs following trauma, burns, and in patients with genetic bone morphogenetic protein (BMP) receptor mutations. The clinical and laboratory evaluation of HO is dependent on radiographic imaging to identify and characterize these lesions. Here we show that despite its inadequacies, plain film radiography and single modality microCT continue to serve as a primary method of HO imaging in nearly 30% of published in vivo literature. Furthermore, we demonstrate that detailed microCT analysis is superior to plain film and single modality microCT radiography specifically in the evaluation of HO formed through three representative models due to its ability to 1) define structural relationships between growing extra-skeletal bone and normal, anatomic bone, 2) provide accurate quantification and growth rate based on volume of the space-occupying lesion, thereby facilitating assessments of therapeutic intervention, 3) identify HO at earlier times allowing for evaluation of early intervention, and 4) characterization of metrics of bone physiology including porosity, tissue mineral density, and cortical and trabecular volume. Examination of our trauma model using microCT demonstrated two separate areas of HO based on anatomic location and relationship with surrounding, normal bone structures. Additionally, microCT allows HO growth rate to be evaluated to characterize HO progression. Taken together, these data demonstrate the need for a paradigm shift in the evaluation of HO towards microCT as a standard tool for imaging.     

Wolbachia Enhances West Nile Virus (WNV) Infection in the Mosquito Culex tarsalis

Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.     

Earthworm-assisted bioremediation of petroleum hydrocarbon–contaminated soils from motorcar mechanic workshops in Ibadan,Oyo State,southwestern Nigeria

Enhanced microbial bioremediation of petroleum hydrocarbon–contaminated (PHC) soils with the earthworm Alma millisoni and the bacterium Bacillus spp. was conducted. The petroleum-contaminated topsoils (PCTS) (0–15 cm) collected from motorcar mechanic workshops were thoroughly mixed, sieved, and air dried for 7 days. The pH, water holding capacity (WHC), total nitrogen (N), organic carbon (OC), heavy metal (HM), and bacteriological analysis of the soil samples were evaluated. The indigenous bacterial isolates were subjected to 1%, 5%, and 50% of spent engine oil (SEO), incubated for 7 days at 37°C, and the isolate with the highest tolerance pattern was used for the remediation. Out of four indigenous bacteria isolated, Bacillus spp. had the highest tolerance to SEO. Preliminary exposure assessments of A. millisoni to PHC soils (100%, 60%, 50%, and 40% PHC) were carried out using 48-h avoidance response, coiling exhibition, swollen clitelium, 14-day survival tests, and antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GPx). Subsequently, four treatments of 1 kg soil mixed with 100%, 75%, 50%, and 0% PCTS were designed and spiked with 20 g of dried cow dung. Each of the treatments consisted of four setups, viz., A. millisoni alone, A. millisoni and Bacillus spp., Bacillus spp. alone, and control. The bacterial counts, total petroleum hydrocarbon (TPH), total and bioavailable HM, and total OC and N of the soils were evaluated every 7 days for 35 days. Significant increases in the activities of CAT, SOD, GPx, and GST compared with control were recorded in A. millisoni exposed to the various treatments. Treatment with combined A. millisoni and Bacillus spp. resulted in significant (p < .05) reduction in TPH, reduction in total and bioavailable heavy metals, and increased total OC and N of the soil compared with other treatments. The percentage reduction in TPH and heavy metals with concomitant increase in total OC and total N recorded in the 50% PHC soils followed the order A. millisoni and Bacillus spp. > A. millisoni alone > Bacillus spp. alone. Hence, enhanced bioremediation using A. millisoni and Bacillus spp. may be a good biocatalyst in the remediation of petroleum hydrocarbon–contaminated soils.