Biological silicon nanoparticles maximize the efficiency of nematicides against biotic stress induced by Meloidogyne incognita in eggplant

Nemours effective management tactics were used to reduce world crop losses caused by plant-parasitic nematodes. Nowadays the metallic nanoparticles are easily developed with desired size and shape. Nanoparticles (NPs) technology becomes a recognized need for researchers. Ecofriendly and biosafe SiNPs are developed from microorganisms. Recently, silicon nanoparticles (SiNPs) have gained novel pesticide properties against numerous agricultural pests. This study assessed the biosynthesis of SiNPs from Fusarium oxysporum SM5. The obtained SiNPs were spherical with a size of 45 nm and a negative charge of −25.65. The nematocidal effect of SiNPs against egg hatching and second-stage juveniles (J2) of root-knot nematode (RKN) (Meloidogyne incognita) was evaluated on eggplant,Solanum melongena L. plants. In vitro, all tested SiNPs concentrations significantly (p ≤ 0.05) inhibited the percentage of egg hatching at a different time of exposure than control. Meanwhile, after 72 h, the percent mortality of J2 ranged from 87.00 % to 98.50 %, with SiNPs (100 and 200 ppm). The combination between SiNPs and the half-recommended doses (0.5 RD) of commercial nematicides namely,  fenamiphos (Femax 40 % EC)^R, nemathorin (Fosthiazate 10 % WG) ^R, and fosthiazate (krenkel 75 % EC) ^R confirmed the increase of egg hatching inhibition and J2 mortality after exposure to SiNPs (100 ppm) mixed with 0.5 RD of synthetic nematicides. The findings suggest that the combination between SiNPs, and 0.5 RD of nematicides reduced nematode reproduction, gall formation, egg masses on roots and final population of J2 in the soil. Therefore, improving the plant growth parameters by reducing the M. incognita population.     

Human DNA polymerase lambda possesses terminal deoxyribonucleotidyl transferase activity and can elongate RNA primers: implications for novel functions

DNA polymerase lambda is a novel enzyme of the family X of DNA polymerases. The recent demonstration of an intrinsic 5'-deoxyribose-5'-phosphate lyase activity, a template/primer dependent polymerase activity, a distributive manner of DNA synthesis and sequence similarity to DNA polymerase beta suggested a novel beta-like enzyme. All these properties support a role of DNA polymerase lambda in base excision repair. On the other hand, the biochemical properties of the polymerisation activity of DNA polymerase lambda are still largely unknown. Here we give evidence that human DNA polymerase lambda has an intrinsic terminal deoxyribonucleotidyl transferase activity that preferentially adds pyrimidines onto 3'OH ends of DNA oligonucleotides. Furthermore, human DNA polymerase lambda efficiently elongates an RNA primer hybridized to a DNA template. These two novel properties of human DNA polymerase lambda might suggest additional roles for this enzyme in DNA replication and repair processes.     

CD45(low)c-Kit(high) cells have hematopoietic properties in the mouse aorta-gonad-mesonephros region

Long-term reconstituting hematopoietic stem cells first arise from the aorta of the aorta-gonad-mesonephros (AGM) region in a mouse embryo. We have previously reported that in cultures of the dispersed AGM region, CD45(low)c-Kit(+) cells possess the ability to reconstitute multilineage hematopoietic cells, but investigations are needed to show that this is not a cultured artifact and to clarify when and how this population is present. Based on the expression profile of CD45 and c-Kit in freshly dissociated AGM cells from embryonic day 9.5 (E9.5) to E12.5 and aorta cells in the AGM from E13.5 to E15.5, we defined six cell populations (CD45(-)c-Kit(-), CD45(-)c-Kit(low), CD45(-)c-Kit(high), CD45(low)c-Kit(high), CD45(high)c-Kit(high), and CD45(high)c-Kit(very low)). Among these six populations, CD45(low)c-Kit(high) cells were most able to form hematopoietic cell colonies, but their ability decreased after E11.5 and was undetectable at E13.5 and later. The CD45(low)c-Kit(high) cells showed multipotency in vitro. We demonstrated further enrichment of hematopoietic activity in the Hoechst dye-effluxing side population among the CD45(low)c-Kit(high) cells. Here, we determined that CD45(low)c-Kit(high) cells arise from the lateral plate mesoderm using embryonic stem cell-derived differentiation system. In conclusion, CD45(low)c-Kit(high) cells are the major hematopoietic cells of mouse AGM.     

Serum Myeloperoxidase as a Biomarker of Asthma Severity Among Adults: A Case Control Study

Background:The contribution of neutrophils is still indistinct in the inflammatory response of bronchial asthma (BAs). Myeloperoxidase (MPO) is an enzyme released from the primary azurophilic granules of the neutrophils. The study aimed to evaluate the levels of serum MPO as a biomarker for the assessment of the level of asthma control. Methods:The study participants included 94 asthmatic patients and 86 healthy controls. The identification of asthma severity had assessed using the ''''Global Initiative for Asthma guidelines''''. Asthmatic adults had divided into three groups: Good (n= 22), partial (n= 30), and poor control (n= 44). Also, patients have been divided again into two groups (treated and untreated) for BAs.Results:The predicted FEV1% and the peak expiratory flow (PEF/L) of all participants had verified by spirometry. The mean patients’ age was 31.9±15.1 year, with a predominance of females. The mean asthma duration was 10.5±8.6 years. Mean spirometric parameters (FEV1 and PEF) were significantly lower among the patients (0.00). Significant higher MPO levels had observed among BAs patients (p-0.00). The MPO levels have not differed significantly with asthma levels and had significant differences with the history of treatment. There was a nonsignificant negative correlation between the mean MPO levels and the spirometry variables among the patients. ROC curves revealed a sensitivity, specificity, accuracy for MPO (80.9%, 72.1%, and 84.3%), respectively to predict asthmatic severity.Conclusion:There were significantly higher MPO levels compared to healthy controls. Levels of serum MPO had a non-significant positive correlation with levels of asthma control, but a negative non-significant correlation with spirometric results. Key Words: Asthma, And Neutrophils, FEV1, MPO, PEF     

First report of detection of the putative receptor of Bacillus thuringiensis toxin Vip3Aa from black cutworm (Agrotis ipsilon)

Black cutworm (BCW) Agrotis ipsilon, an economically important lepidopteran insect, has attracted a great attention. Bacillus thuringiensis (Bt) is spore forming soil bacteria and is an excellent environment-friendly approach for the control of phytophagous and disease-transmitting insects. In fact, bio-pesticide formulations and insect resistant transgenic plants based on the bacterium Bt delta-endotoxin have attracted worldwide attention as a safer alternative to harmful chemical pesticides. The major objective of the current study was to understand the mechanism of interaction of Bt toxin with its receptor molecule(s). The investigation involved the isolation, identification, and characterization of a putative receptor – vip3Aa. In addition, the kinetics of vip toxin binding to its receptor molecule was also studied. The present data suggest that Vip3Aa toxin bound specifically with high affinity to a 48-kDa protein present at the brush border membrane vesicles (BBMV) prepared from the midgut epithelial cells of BCW larvae.     

Chalcones as potent tyrosinase inhibitors: the importance of a 2,4-substituted resorcinol moiety

Compounds, which inhibit tyrosinase, could be effective as depigmenting agents. We have introduced a group of mono-, di-, tri- and tetra-substituted hydroxychalcones as effective tyrosinase inhibitors, showing that the most important factor determining tyrosinase inhibition efficiency is the position of the hydroxyl group(s) rather their number. The aim of the present study was to investigate the contribution of the different functional groups of the tetrahydroxychalcones to their inhibitory potency, with a view to optimizing the design of whitening agents. Four tetrahydroxychalcones were evaluated, the commercially available Butein and other three were synthesized, and their inhibitory effect on tyrosinase was tested. Results showed that a 2,4-substituted resorcinol subunit on ring B contributed the most to inhibitory potency. Changing the resorcinol substitute to position 3,5- or placing it on ring A significantly diminished the inhibitory effect of the compounds. A catechol subunit on ring A acted as a metal chelator (in the presence of copper ions) and as a competitive inhibitor (in the presence of tyrosinase), while a catechol on ring B oxidized to o-quinone (in the presence of both copper ions and tyrosinase). Three of the compounds also demonstrated antioxidant activity, which may contribute to the prevention of pigmentation. An examination of correlations between inhibitory activity and physical properties of the chalcones tested (such as dissociation energy and molecular planarity) showed positive correlation with the moment dipole value in the Y-axis, which may be used as an indicator of the inhibitory potential of new molecules. The present study revealed two very active tyrosinase inhibitors, 2,4,3',4'-hydroxychalcone and 2,4,2',4'-hydroxychalcone (with IC50 of 0.2 and 0.02 microM, respectively). Structure-related activity studies added some understanding of the role and contribution of different functional groups associated with tyrosinase inhibitors.     

Global metabolic profiling analysis on human urine by UPLC-TOFMS: issues and method validation in nutritional metabolomics

Optimisation and method validation was assessed here for metabolic profiling analysis of urine samples using UPLC-TOFMS. A longer run time of 31 min revealed greater reproducibility, and the higher number of variables was identified as compared to shortened run times (10 and 26 min). We have also implemented two QC urine samples enabling the assessment of the quality and reproducibility of the data generated during the whole analytical workflow (retention time drift, mass precision and fluctuation of the ion responses over time). Based on the QC data, suitable standards for ensuring consistent analytical results for metabolomics applications using the UPLC-MS techniques are recommended.     

Invasion status of Florida bass Micropterus floridanus (Lesueur, 1822) in South Africa

Largemouth bass Micropterus salmoides are a popular North American angling species that was introduced into South Africa in 1928. To enhance the largemouth bass fisheries, Florida bass Micropterus floridanus were introduced into KwaZulu Natal, South Africa, in 1980. Knowledge on the status of M. floridanus in South Africa is required, because it lives longer and reaches larger sizes than M. salmoides, which may result in heightened impacts on native biota. Because M. floridanus are morphologically similar, but genetically distinct from M. salmoides, the distribution of this species was assessed by genetically screening 185 Micropterus sp. individuals sampled from 20 localities across South Africa using the mitochondrial ND2 gene. Individuals with mitochondrial DNA matching M. salmoides were recovered from 16 localities, whereas M. floridanus mitochondrial DNA was recovered from 13 localities. At nine localities (45%), the mitochondrial DNA of both species was detected. These results demonstrate M. floridanus dispersal to multiple sites across South Africa.     

Effect of seed inoculation,mycorrhizal infection and organic amendment on wheat growth

Summary The effect of seed inoculation withAzotobacter spp. orAzospirillum spp., and garbage amendment (0.5%), on the growth of wheat was studied in a field experiment under sub-tropical conditions. Two levels of N fertilizer were applied, the usual field rate (150 kg N ha^–1) and half this amount. Tillering of plants, dry matter contents and nitrogenase activity were determined 30, 60 and 90 days after sowing. At the end of the experimental period, spore numbers and percentage of mycorrhizal infection were observed in the rhizosphere and root systems of plants. Straw and grain yields were also determined. The results of this study showed that seed inoculation and/or organic amendment stimulated plant growth, nitrogenase activity and mycorrhizal infection. This was more noticeable withAzotobacter than withAzospirillum. Inoculation withAzotobacter together with 1/2 N dose and organic amendment was the most effective application (19.75 and 10.70 t ha^–1 were recorded for straw and grain yield, respectively).     

Micellar‐based spectrofluorimetric method for the selective determination of ledipasvir in the presence of sofosbuvir: application to dosage forms and human plasma

A fast, low‐cost, sensitive, and selective spectrofluorimetric method for the determination of ledipasvir was developed and validated. The method is based on an enhancement in the native fluorescence intensity of ledipasvir by 500% of its original value by the formation of hydrogen bonds between the cited drug and Tween‐20 in the micellar system (pH = 5.0). All fluorescence measurements were carried out at 425 nm and 340 nm for emission and excitation wavelengths, respectively. A linear relationship between the concentration of ledipasvir and the observed fluorescence intensity was achieved in the range of 0.1–2.0 μg ml^?1 with 0.028, 0.084 μg ml^?1, for detection and quantitation limits, respectively. The acquired selectivity and sensitivity using the proposed method facilitate the analysis of ledipasvir in spiked human plasma with sufficient percentage recovery (95.36–99.30%). The proposed method was developed and validated according to International Council for Harmonisation (ICH) guidelines. Moreover, the cited drug was successfully determined in its pharmaceutical dosage form using the proposed method. In addition, the validity of the proposed results was statistically confirmed using Student's t‐test, variance ratio F‐test, and interval hypothesis test.