Non‐cultivated grass hosts of yellow dwarf viruses in Ethiopia and their epidemiological consequences on cultivated cereals

The yellow dwarf (YD) disease complex epidemics in cultivated cereals grown in a specific period of the year mainly depend on the presence of potential reservoir alternative hosts harbouring both the viruses and the vectors over the off‐season and serve as a source of inoculum in subsequent cropping season, further spread being supported by efficient aphid vectors. As such, an extensive and intensive exploration to generate base line information on the identity and prevalence of YD viruses [barley yellow dwarf virus (BYDV)‐PAV, BYDV‐MAV and BYDV‐SGV; cereal yellow dwarf virus (CYDV)‐RPV; and maize yellow dwarf virus (MYDV)‐RMV] on wild annual and perennial grasses and forage cereals alternative hosts was conducted consecutively during 2013–2015 main‐ and short‐rainy seasons in cereals growing belts of Ethiopia. Random sampling was employed to collect the samples that were tested by the tissue blot immunoassay (TBIA) to identify the YDVs associated with the hosts using a battery of virus‐specific polyclonal antibodies. Of 13,604 samples analysed, YDVs were detected in 392 (2.9%) samples, which consisted of various wild grasses, forage cereals and three cultivated crops. YDVs were identified from at least 26 grass species and forage cereals, some of them are new records, and some are previously documented hosts. To our knowledge, this is the first report of YDV infection of Andropogon abyssinicus (FresenR.Br. ex Fresen.) (BYDV‐PAV), Avena abyssinica Hochst (BYDV‐PAV), Bromus pectinatus Thunb. (BYDV‐PAV and BYDV‐MAV), Eragrostis tef (Zuccagni) Trotter (BYDV‐PAV), Eragrostis sp. (BYDV‐PAV), Hyparrhenia anthistrioides Stapf. (BYDV‐PAV), Panicum coloratum L. (BYDV‐PAV), Polypogon monspeliensis (L.) Desf. (BYDV‐PAV), Setaria pumila (Poir.) Roem & Schult (BYDV‐PAV, BYDV‐SGV and MYDV‐RMV), Setaria australiensis (Scribn. & Merrill) Vickery (BYDV‐PAV, BYDV‐MAV and CYDV‐RPV) and Snowdenia polystachya (Fresen.) Pilg (BYDV‐PAV, BYDV‐MAV, BYDV‐SGV, CYDV‐RPV and MYDV‐RMV).     

Phylogenetic analysis of norovirus isolates involved in some Canadian gastroenteritis outbreaks in 2004 and 2005

Noroviruses are recognized as the most common cause of nonbacterial gastroenteritis worldwide. In this study, we investigated the molecular epidemiology of noroviral isolates in Canada from 2004 to 2005 by sequencing the RNA polymerase gene and capsid N-terminal/shell (N/S) domain. Norovirus genogroups I and II were thus found to have co-circulated in Canada during the studied period, with a higher incidence of genogroup II (95.7%). The GII-4 or Lordsdale subgroup was the predominant genotype, suggesting that norovirus genogroup II is the major cause of viral gastroenteritis in Canada, as it is in many other countries. Phylogenetic analyses of the RNA polymerase gene and the capsid N/S domain indicated different genotypes for 2 strains, suggesting probable genetic recombination. Sequencing of the norovirus polymerase gene may reflect actual classification but should be supported by sequence information obtained from the capsid gene.     

Phytomining to re-establish phosphorus-poor soil conditions for nature restoration on former agricultural land

Plant and Soil - Phosphorus deficiency often limits crop productivity, while phosphate rock, which is used to produce phosphorus fertilisers, is a non-renewable resource. Formation of cluster roots...     

Correction to: Phytomining to re-establish phosphorus-poor soil conditions for nature restoration on former agricultural land

Plant and Soil - Litter decomposition in serpentine ecosystems has been studied solely addressing heavy metals like Ni. We aimed to show how leaf nutrients, cell-wall components and lamina mass per...     

Carotenoids reverse multidrug resistance in cancer cells by interfering with ABC-transporters

Proteins of the ATP-binding cassette superfamily, mainly P-glycoprotein (P-gp; MDR1), play an important role in the development of multidrug resistance (MDR) in cancer cells and thus in the potential failure of chemotherapy. A selection of carotenoids (β-carotene, crocin, retinoic acid, canthaxanthin, and fucoxanthin) was investigated whether they are substrates of P-gp, and if they can reverse MDR in resistant Caco-2 and CEM/ADR5000 cells as compared to the sensitive parent cell line CCRF-CEM. The activity of ABC transporter was determined in resistant and sensitive cells by spectrofluorometry and flow cytometry using the substrates doxorubicin, rhodamine 123, and calcein as fluorescent probes. The carotenoids increased accumulation of these P-gp substrates in a dose-dependent manner indicating that they themselves also function as substrates. Fucoxanthin and canthaxanthin (50-100μM) produced a 3-5-fold higher retention of the fluorescent probes than the known competitive inhibitor verapamil. Carotenoids showed a low cytotoxicity in cells with MDR with IC(50) values between 100 and 200μM. The combination of carotenoids with eight structurally different cytotoxic agents synergistically enhanced their cytotoxicity in Caco-2 cells, probably by inhibiting the function of the ABC transporters. For example, fucoxanthin synergistically enhanced the cytotoxicity of 5-FU 53.37-fold, of vinblastine 51.01-fold, and of etoposide 12.47-fold. RT-PCR was applied to evaluate the mRNA levels of P-gp in Caco-2 cells after treatment with carotenoids. Fucoxanthin and canthaxanthin significantly decreased P-gp levels to 12% and 24%, respectively as compared to untreated control levels (p<0.001). This study implies that carotenoids may be utilised as chemosensitisers, especially as adjuvants in chemotherapy.     

Preparation and evaluation of warfarin-β-cyclodextrin loaded chitosan nanoparticles for transdermal delivery

The main objective of the present work was to prepare warfarin-β-cyclodextrin (WAF-β-CD) loaded chitosan (CS) nanoparticles for transdermal delivery. CS is a hydrophilic carrier therefore, to overcome the hydrophobic nature of WAF and allow its incorporation into CS nanoparticles, WAF was first complexed with β-cyclodextrin (β-CD). CS nanoparticles were prepared by ionotropic pre-gelation using tripolyphosphate (TPP). Morphology, size and structure characterization of nanoparticles were carried out using SEM, TEM and FTIR, respectively. Nanoparticles prepared with 3:1 CS:TPP weight ratio and 2mg/ml final CS concentration were found optimum. They possessed spherical particles (35±12nm diameter) with narrow size distribution (PDI=0.364) and 94% entrapment efficiency. The in vitro release as well as the ex vivo permeation profiles of WAF-β-CD from the selected nanoparticle formulation were studied at different time intervals up to 8h. In vitro release of WAF-β-CD from CS nanoparticles followed a Higuchi release profile whereas its ex vivo permeation (at pH 7.4) followed a zero order permeation profile. Results suggested that the developed WAF-β-CD loaded CS carrier could offer a controlled and constant delivery of WAF transdermally.     

A proteomic-based approach to study underlying molecular responses of the small intestine of Wistar rats to genetically modified corn (MON810)

A genetically modified (GM) commercial corn variety, MON810, resistant to European corn borer, has been shown to be non-toxic to mammals in a number of rodent feeding studies carried out in accordance with OECD Guidelines. Insect resistance results from expression of the Cry1Ab gene encoding an insecticidal Bt protein that causes lysis and cell death in susceptible insect larvae by binding to midgut epithelial cells, which is a key determinant of Cry toxin species specificity. Whilst whole animal studies are still recognised as the ‘gold standard’ for safety assessment, they only provide indirect evidence for changes at the cellular/organ/tissue level. In contrast, omics-based technologies enable mechanistic understanding of toxicological or nutritional events at the cellular/receptor level. To address this important knowledge-gap and to gain insights into the underlying molecular responses in rat to MON810, differential gene expression in the epithelial cells of the small intestine of rats fed formulated diets containing MON810, its near isogenic line, two conventional corn varieties, and a commercial (Purina?) corn-based control diet were investigated using comparative proteomic profiling. Pairwise and five-way comparisons showed that the majority of proteins that were differentially expressed in the small intestine epithelial cells in response to consumption of the different diets in both 7-day and 28-day studies were related to lipid and carbohydrate metabolism and protein biosynthesis. Irrespective of the diet, a limited number of stress-related proteins were shown to be differentially expressed. However these stress-related proteins differed between diets. No adverse clinical or behavioural effects, or biomarkers of adverse health, were observed in rats fed GM corn compared to the other corn diets. These findings suggest that MON810 has negligible effects on the small intestine of rats at the cellular level compared with the well-documented toxicity observed in susceptible insects.