Larvicidal potential of gold and silver nanoparticles synthesized using Acalypha fruticosa leaf extracts against Culex pipiens (Culicidae: Diptera)

Plant secondary metabolites have been recently used for the synthesis of different nanoparticles. The present investigation aimed at evaluating the effect of gold (AuNPs) and silver (AgNPs) nanoparticles synthesized using Acalypha fruticosa leaf extracts to control the mosquito Culex pipiens. The A. fruticosa AuNPs and AgNPs spectra displayed their maximum absorption at 550 nm and 440 nm, respectively. The infrared spectra revealed different functional groups related to different chemical compounds. The larval mortality of aqueous leaf extract of A. fruticosa was 499.54 ppm (LC₅₀) and 1734.06 ppm (LC₉₀) after 24 h of treatment. This study revealed that AuNP (LC₅₀, 30.2 and LC₉₀, 104.83 ppm) and AgNP (LC₅₀, 52.86 and LC₉₀, 157.227 ppm) preparations were highly effective compared to the A. fruticosa extract alone and also more affordable, as a smaller amount was required. The present findings show the potential larvicidal effect of the synthesized AuNPs and AgNPs for the control of mosquito-mediated disease transmission.     

Bayesian Estimation Using Ranked Set Sampling

Bayesian Estimation of the parameter of a distribution is considered using Ranked set sampling (RSS). It is shown that for at least one RSS plan, the Bayes estimator has smaller Bayes risk than the Bayes estimator using simple random sampling (SRS). Furthermore, for exponential family with conjugate prior, the Bayes estimator of the mean using balanced RSS dominates, in terms of its Bayes risk, the Bayes estimator of the mean using SRS. This procedure is used to estimate the average Milk yield of four hundreds and two sheep. The empirical efficiency supports the theoretical findings.     

The Escherichia coli UVM response is accompanied by an SOS-independent error-prone DNA replication activity demonstrable in vitro

UVM is an SOS-independent inducible response characterized by elevated mutagenesis at a site-specific 3, N4-ethenocytosine (epsilonC) residue borne on M13 single-stranded DNA transfected into Escherichia coli cells pretreated with DNA-damaging agents. By constructing and using E. coli strain AM124 (polA polB umuDC dinB lexA1[Ind-]), we show here that the UVM response is manifested in cells deficient for SOS induction, as well as for all four of the 'non-replicative' DNA polymerases, namely DNA polymerase I (polA), II (polB), IV (dinB) and V (umuDC). These results confirm that UVM represents a novel, previously unidentified cellular response to DNA-damaging agents. To address the question as to whether the UVM response is accompanied by an error-prone DNA replication activity, we applied a newly developed in vitro replication assay coupled to an in vitro mutation analysis system. In the assay, circular M13 single-stranded DNA bearing a site-specific lesion is converted to circular double-stranded replicative-form DNA in the presence of cell extracts and nucleotide precursors under conditions that closely mimic M13 replication in vivo. The newly synthesized (minus) DNA strand is selectively amplified by ligation-mediated polymerase chain reaction (LM-PCR), followed by a multiplex sequence analysis to determine the frequency and specificity of mutations. Replication of DNA bearing a site-specific epsilonC lesion by cell extracts from uninduced E. coli AM124 cells results in a mutation frequency of about 13%. Mutation frequency is elevated fivefold (to 58%) in cell extracts from UVM-induced AM124 cells, with C --> A mutations predominating over C --> T mutations, a specificity similar to that observed in vivo. These results, together with previously reported data, suggest that the UVM response is mediated through the induction of a transient error-prone DNA replication activity and that a modification of DNA polymerase III or the expression of a previously unidentified DNA polymerase may account for the UVM phenotype.     

Science Educational Outreach Programs That Benefit Students and Scientists

Both scientists and the public would benefit from improved communication of basic scientific research and from integrating scientists into education outreach, but opportunities to support these efforts are limited. We have developed two low-cost programs—"Present Your PhD Thesis to a 12-Year-Old" and "Shadow a Scientist”—that combine training in science communication with outreach to area middle schools. We assessed the outcomes of these programs and found a 2-fold benefit: scientists improve their communication skills by explaining basic science research to a general audience, and students'' enthusiasm for science and their scientific knowledge are increased. Here we present details about both programs, along with our assessment of them, and discuss the feasibility of exporting these programs to other universities.     

Expression analysis of the nucleocytoplasmic lectin 'Orysata' from rice in Pichia pastoris

The Oryza sativa lectin, abbreviated Orysata, is a mannose-specific, jacalin-related lectin expressed in rice plants after exposure to certain stress conditions. Expression of a fusion construct containing the rice lectin sequence linked to enhanced green fluorescent protein in Bright Yellow 2 tobacco cells revealed that Orysata is located in the nucleus and the cytoplasm of the plant cell, indicating that it belongs to the class of nucleocytoplasmic jacalin-related lectins. Since the expression level of Orysata in rice tissues is very low the lectin was expressed in the methylotrophic yeast Pichia pastoris with the Saccharomyces α-factor sequence to direct the recombinant protein into the secretory pathway and express the protein into the medium. Approximately 12 mg of recombinant lectin was purified per liter medium. SDS/PAGE and western blot analysis showed that the recombinant lectin exists in two molecular forms. Far western blot analysis revealed that the 23 kDa lectin polypeptide contains an N-glycan which is absent in the 18.5 kDa polypeptide. Characterization of the glycans present in the recombinant Orysata revealed high-mannose structures, Man9-11 glycans being the most abundant. Glycan array analysis showed that Orysata interacts with high-mannose as well as with more complex N-glycan structures. Orysata has potent anti-human immunodeficiency virus and anti-respiratory syncytial virus activity in cell culture compared with other jacalin-related lectins.     

Morphology of the stomach of the tropical house gecko Hemidactylus mabouia (Squamata: Gekkonidae)

Rodrigues Sartori, S. S., Nogueira, K. O. P. C., Rocha, A. S. and Neves, C. A. 2011. Morphology of the stomach of the tropical house gecko Hemidactylus mabouia (Squamata: Gekkonidae). —Acta Zoologica (Stockholm) 92 : 179–186. Hemidactylus mabouia is a common species in Brazil, which facilitates its use in research in several areas and allows display it as a benchmark for studies with reptiles. To study the morphology of the stomach of H. mabouia, we carried out anatomical, histological and histochemical analysis. The stomach of H. mabouia is ‘J’ shaped and can be divided into oral fundic (OF), aboral fundic (AF) and pyloric regions. The surface epithelium is composed of mucosecretory cells (MC) containing neutral mucins. In the lamina propria of the OF region, are large ramified tubulo‐acinar glands, which become smaller, less ramified and more tubular towards the AF region, and are simple tubular and short in the pyloric region. The fundic glands contain differentiated neck and pit. The neck is composed of MC containing neutral mucins and the pit is made of oxyntopeptic cells (OC). The OC of the OF region contained many zymogen granules, while those of the AF region contained few zymogen granules and many mitochondria, which suggests the existence of a gradient of pepsinogen and hydrochloric acid secretion. Pyloric glands consisted of MC containing neutral mucins and both argyrophil and argentaffin endocrine cells.     

Detection of suspicious cells and rejection of artefacts in cervical cytology using the Leyden Television Analysis System.

In slide based automation of cervical cytology the first stage of analysis involves finding possibly suspicious cells, or areas on the slide with these types of cells. By using a television based system such as the Leyden Television Analysis System (LEYTAS), a number of detection methods can be applied to rapidly screen a large number of fields automatically for suspicious cells. In this paper, results using a parameter based on increased nuclear DNA content of cells are given and a second detection method based on a chromatin pattern feature, called chromatin contrast, is discussed. Two blind trials on 41 positive and 22 negative cervical slides, using the Leyden Television Analysis System to detect suspicious cells with an increased nuclear DNA content, were promising. In 1 of the 41 positive cases no suspicious cells were found. In the negative specimens, suspicious cells were detected in 1 of 9 cases and 1 of 13 cases, with the two detection parameters investigated. These findings are discussed and some automatic artefact rejection procedures with preliminary results are given.     

Proteomic and microarray analyses of the Dictyostelium Zak1-GSK-3 signaling pathway reveal a role in early development

GskA, the Dictyostelium GSK-3 orthologue, is modified and activated by the dual-specificity tyrosine kinase Zak1, and the two kinases form part of a signaling pathway that responds to extracellular cyclic AMP. We identify potential cellular effectors for the two kinases by analyzing the corresponding null mutants. There are proteins and mRNAs that are altered in abundance in only one or the other of the two mutants, indicating that each kinase has some unique functions. However, proteomic and microarray analyses identified a number of proteins and genes, respectively, that are similarly misregulated in both mutant strains. The positive correlation between the array data and the proteomic data is consistent with the Zak1-GskA signaling pathway's functioning by directly or indirectly regulating gene expression. The discoidin 1 genes are positively regulated by the pathway, while the abundance of the H5 protein is negatively regulated. Two of the targets, H5 and discoidin 1, are well-characterized markers for early development, indicating that the Zak1-GskA pathway plays a role in development earlier than previously observed.     

Genetic variation among Saudi tomato (Solanum lycopersicum L.) landraces studied using SDS-PAGE and SRAP markers

Genetic diversity among seven Saudi tomato landraces collected from different regions of the country was assessed using SDS-PAGE and molecular (sequence-related amplified polymorphism- SRAP) markers. A total of 19 alternative protein bands with different mobility rates were identified within a molecular weight range of 9.584–225?KDa, with 53% polymorphism. Specific protein bands were observed in the “Hail 548” and “Qatif 565” landraces. Genetic similarity based on Jaccard’s coefficient ranged from 0.53 to 1.00, with an average of 0.72. For molecular evaluation, 143 amplicons (fragments) were generated using 27 SRAP primer pair combinations, of which 88 were polymorphic across all the landraces. The PIC values ranged from 0.46 to 0.90, with an average of 0.76. All landraces showed an average of 0.66 similarity coefficient value. The UPGMA dendrogram supported by principal coordinate analysis (PCoA) revealed clusters of the landraces that almost corresponded to their geographical origin. Thus, seed storage protein profiling based on SDS-PAGE and SRAP markers can efficiently be used to assess genetic variability among tomato germplasms. The information obtained in the analysis will be of great interest in the management of ex situ collections for utilization in breeding programs or for direct use in quality markets.