Elemental analysis of atmospheric aerosols in Gaborone

Aerosols are mixture of solid and liquid particles and have considerable variation in terms of their chemical composition and size. In this study the elemental composition of aerosol particles in the atmosphere of a city, Gaborone, was carried out. The elemental analysis was done by environmental scanning electron microscope (ESEM). The results clearly show that the composition of the particles observed was very complex. It also showed the presence of elements Al, Si, Fe, K, Ca, Mg, Zn, Na, Cu, Pb, Ti, Ni, Pt, Au and Cr. The most frequently occurred element was silicon and the least frequently occurred element was platinum. Our measurements also revealed that the elements which had an amount more than 90% were copper, lead, nickel and gold

Effects of boron fertilization on calcium:boron ratio and boron mobility in cauliflower

Greenhouse studies were conducted on two different alfisols, Bajaura (Loam) and Junga (Sandy loam), that are deficient in boron (B) for cauliflower (Brassica oleracea L. var. botrytis). The calcium:boron (Ca:B) ratio in cauliflower leaves with applied B (1 to 3 mg kg−1 soil) varied from 1276 to 521 in the Bajaura soil with high exchangeable-Ca and no deficiency or toxicity symptoms were evident. In the Junga soil with low exchangeable-Ca, however, the Ca:B ratio varied from 505 to 223 with toxicity symptoms visible when 2 and 3 mg kg−1 B has been applied. This corresponds to a Ca:B ratio of 256 and 223. Farm yard manure application showed an ameliorating effect on Ca:B ratio with a tendency to decrease a high Ca:B ratio in the absence of B application and increase a lower Ca:B ratio when incorporated with higher levels of B. The B mobility from leaves to curd decreased with increasing levels of B application and thus provided a circumstantial evidence for B retranslocation under conditions of low B supply i.e. conditional mobility

The role of tissue transglutaminase (TG2) in regulating the tumour progression of the mouse colon carcinoma CT26

The multifunctional enzyme tissue transglutaminase (TG2) is reported to both mediate and inhibit tumour progression. To elucidate these different roles of TG2, we established a series of stable-transfected mouse colon carcinoma CT26 cells expressing a catalytically active (wild type) and a transamidating-inactive TG2 (Cys277Ser) mutant. Comparison of the TG2-transfected cells with the empty vector control indicated no differences in cell proliferation, apoptosis and susceptibility to doxorubicin, which correlated with no detectable changes in the activation of the transcription factor NF-?B. TG2-transfected cells showed increased expression of integrin ß3, and were more adherent and less migratory on fibronectin than control cells. Direct interaction of TG2 with ß3 integrins was demonstrated by immunoprecipitation, suggesting that TG2 acts as a coreceptor for fibronectin with ß3 integrins. All cells expressed the same level of TGFß receptors I and II, but only cells transfected with active TG2 had increased levels of TGFß1 and matrix-deposited fibronectin, which could be inhibited by TG2 site-directed inhibitors. Moreover, only cells transfected with active TG2 were capable of inhibiting tumour growth when compared to the empty vector controls. We conclude that in this colon carcinoma model increased levels of active TG2 are unfavourable to tumour growth due to their role in activation of TGFß1 and increased matrix deposition, which in turn favours increased cell adhesion and a lowered migratory and invasive behaviour

Enriching Peptide Libraries for Binding Affinity and Specificity Through Computationally Directed Library Design

Peptide reagents with high affinity or specificity for their target protein interaction partner are of utility for many important applications. Optimization of peptide binding by screening large libraries is a proven and powerful approach. Libraries designed to be enriched in peptide sequences that are predicted to have desired affinity or specificity characteristics are more likely to yield success than random mutagenesis. We present a library optimization method in which the choice of amino acids to encode at each peptide position can be guided by available experimental data or structure-based predictions. We discuss how to use analysis of predicted library performance to inform rounds of library design. Finally, we include protocols for more complex library design procedures that consider the chemical diversity of the amino acids at each peptide position and optimize a library score based on a user-specified input model.National Institute of General Medical Sciences (U.S.) (Award R01 GM110048

A new WHO bottle bioassay method to assess the susceptibility of mosquito vectors to public health insecticides: results from a WHO-coordinated multi-centre study

BACKGROUND: The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently. This study aimed to develop and validate a new WHO glass bottle bioassay method as an alternative to the WHO standard insecticide tube test to monitor mosquito susceptibility to new public health insecticides with particular modes of action, physical properties or both. METHODS: A multi-centre study involving 21 laboratories worldwide generated data on the susceptibility of seven mosquito species (Aedes aegypti, Aedes albopictus, Anopheles gambiae sensu stricto [An. gambiae s.s.], Anopheles funestus, Anopheles stephensi, Anopheles minimus and Anopheles albimanus) to seven public health insecticides in five classes, including pyrethroids (metofluthrin, prallethrin and transfluthrin), neonicotinoids (clothianidin), pyrroles (chlorfenapyr), juvenile hormone mimics (pyriproxyfen) and butenolides (flupyradifurone), in glass bottle assays. The data were analysed using a Bayesian binomial model to determine the concentration-response curves for each insecticide-species combination and to assess the within-bioassay variability in the susceptibility endpoints, namely the concentration that kills 50% and 99% of the test population (LC50 and LC99, respectively) and the concentration that inhibits oviposition of the test population by 50% and 99% (OI50 and OI99), to measure mortality and the sterilizing effect, respectively. RESULTS: Overall, about 200,000 mosquitoes were tested with the new bottle bioassay, and LC50/LC99 or OI50/OI99 values were determined for all insecticides. Variation was seen between laboratories in estimates for some mosquito species-insecticide combinations, while other test results were consistent. The variation was generally greater with transfluthrin and flupyradifurone than with the other compounds tested, especially against Anopheles species. Overall, the mean within-bioassay variability in mortality and oviposition inhibition were < 10% for most mosquito species-insecticide combinations. CONCLUSION: Our findings, based on the largest susceptibility dataset ever produced on mosquitoes, showed that the new WHO bottle bioassay is adequate for evaluating mosquito susceptibility to new and promising public health insecticides currently deployed for vector control. The datasets presented in this study have been used recently by the WHO to establish 17 new insecticide discriminating concentrations (DCs) for either Aedes spp. or Anopheles spp. The bottle bioassay and DCs can now be widely used to monitor baseline insecticide susceptibility of wild populations of vectors of malaria and Aedes-borne diseases worldwide

Anti-Angiogenic Activity of a Small Molecule STAT3 Inhibitor LLL12

Background: Recent data indicate the Signal Transducer and Activator of Transcription 3 (STAT3) pathway is required for VEGF production and angiogenesis in various types of cancers. STAT3 inhibitors have been shown to reduce tumor microvessel density in tumors but a direct anti-angiogenic activity has not been described. Methodology/Principal Findings: We investigated the direct action of a small molecule inhibitor of STAT3 (LLL12) in human umbilical cord vascular endothelial cells (HUVECs) in vitro, in a Matrigel model for angiogenesis in vivo, and its antitumor activity in a xenograft model of osteosarcoma. LLL12 (100 nM) significantly inhibited VEGF-stimulated STAT3 phosphorylation in HUVECs, reduced their proliferation/migration and inhibited VEGF-induced tube formation. Morphologic analysis of LLL12 treated HUVECs demonstrated marked changes in actin/tubulin distribution and bundling. In scid mice, LLL12 reduced microvessel invasion into VEGF-infused Matrigel plugs by,90 % at a dose of 5 mg/kg daily. Following a period of tumor progression (2 weeks), LLL12 completely suppressed further growth of established OS-1 osteosarcoma xenografts. Pharmacodynamic studies showed robust phosphorylated STAT3 in control tumors, whereas phospho-STAT3 was not detected in LLL12-treated OS-1 tumors. Treated tumors demonstrated decreased proliferation (Ki67 staining), and decreased microvessel density (CD34 staining), but no significant increase in apoptosis (TUNEL staining), relative to controls. Assay of angiogenic factors, using an antibody array, showed VEGF, MMP-9, Angiopoietin1/2, Tissue Factor and FGF-

Support Vector Machine based method to distinguish proteobacterial proteins from eukaryotic plant proteins

Background: Members of the phylum Proteobacteria are most prominent among bacteria causing plant diseases that result in a diminution of the quantity and quality of food produced by agriculture. To ameliorate these losses, there is a need to identify infections in early stages. Recent developments in next generation nucleic acid sequencing and mass spectrometry open the door to screening plants by the sequences of their macromolecules. Such an approach requires the ability to recognize the organismal origin of unknown DNA or peptide fragments. There are many ways to approach this problem but none have emerged as the best protocol. Here we attempt a systematic way to determine organismal origins of peptides by using a machine learning algorithm. The algorithm that we implement is a Support Vector Machine (SVM).Result: The amino acid compositions of proteobacterial proteins were found to be different from those of plant proteins. We developed an SVM model based on amino acid and dipeptide compositions to distinguish between a proteobacterial protein and a plant protein. The amino acid composition (AAC) based SVM model had an accuracy of 92.44% with 0.85 Matthews correlation coefficient (MCC) while the dipeptide composition (DC) based SVM model had a maximum accuracy of 94.67% and 0.89 MCC. We also developed SVM models based on a hybrid approach (AAC and DC), which gave a maximum accuracy 94.86% and a 0.90 MCC. The models were tested on unseen or untrained datasets to assess their validity.Conclusion: The results indicate that the SVM based on the AAC and DC hybrid approach can be used to distinguish proteobacterial from plant protein sequences.Peer reviewedBiochemistry and Molecular Biolog

Leptospira seroprevalence and associations between seropositivity, clinical disease and host factors in horses

<p>Abstract</p> <p>Background</p> <p>A cross-sectional study was carried out to determine the seroprevalence of different serovars of <it>Leptospira </it>spp. and their association with clinical disease and host factors in Swedish horses.</p> <p>Methods</p> <p>Sera from 2017 horses brought to equine clinics during 1997–98 were investigated. The sera were examined by microscopic agglutination test for the presence of antibodies against the following <it>L. interrogans </it>serovars: Bratislava strain Jez, Icterohaemorrhagiae strain Kantorowicz and Pomona strain Pomona and also <it>L. kirschneri </it>sv Grippotyphosa strain Duyster and <it>L. borgpetersenii </it>sv Sejroe strain M 84. Host factors, disease factors, season, pasture access and outdoor confinement variables were analysed with respect to seropositivity to sv Bratislava and Icterohaemorrhagiae. Multivariable logistic regression was used to model seropositivity to sv Bratislava and Icterohaemorrhagiae (seroprevalence > 8%).</p> <p>Results</p> <p>The seroprevalence, at a cut-off 1:100, were for sv Bratislava (16.6%), Icterohaemorrhagiae (8.3%), Sejroe (1.2%), Pomona (0.5%) and Grippotyphosa (0.4%). In the multivariable analysis, it was demonstrated that seroprevalence increased with age for sv Bratislava and Icterohaemorrhagiae. For sv Bratislava the seasons April – June and October – December and for sv Icterohaemorrhagiae October – December had higher seroprevalences than other seasons. Horses not used for racing had higher levels of seropositivity to sv Bratislava. Furthermore, horses with respiratory problems as well as horses with fatigue had higher levels of seropositivity to sv Bratislava. Ponies and coldbloods, and horses with access to pasture, had lower seroprevalence for sv Icterohaemorrhagiae. Healthy horses had lower seroprevalence for sv Icterohaemorrhagiae, than non-healthy horses.</p> <p>Conclusion</p> <p>There was no significant association between clinical signs and disease and positive titres to sv Bratislava (except for the association between respiratory problems and fatigue and seropositivity to sv Bratislava). The results suggest that horses with increasing age and exposed to factors associated with outdoor life had an increased seroprevalence for sv Bratislava, indicating that horses get infected from outdoor and/or are exposed to shedding from other horses (management dependent). For sv Icterohaemorrhagiae, management possibly plays a role as ponies and coldbloods as well as healthy horses had lower seroprevalence. Overall, the age of the horse should be taken into consideration when evaluating the titre as the average healthy horse has a higher titre than a young horse.</p