Mutations in the fusion protein cleavage site of avian paramyxovirus serotype 2 increase cleavability and syncytium formation but do not increase viral virulence in chickens

Avian paramyxovirus serotype 2 (APMV-2) is one of the nine serotypes of APMV, which infect a wide variety of avian species around the world. In this study, we constructed a reverse genetics system for recovery of infectious recombinant APMV-2 strain Yucaipa (APMV-2/Yuc) from cloned cDNA. The rescued recombinant virus (rAPMV-2) resembled the biological virus in growth properties in vitro and in pathogenicity in vivo. The reverse genetics system was used to analyze the role of the cleavage site of the fusion (F) protein in viral replication and pathogenesis. The cleavage site of APMV-2/Yuc (KPASR↓F) contains only a single basic residue (position -1) that matches the preferred furin cleavage site [RX(K/R)R↓]. (Underlining indicates the basic amino acids at the F protein cleavage site, and the arrow indicates the site of cleavage.) Contrary to what would be expected for this cleavage sequence, APMV-2 does not require, and is not augmented by, exogenous protease supplementation for growth in cell culture. However, it does not form syncytia, and the virus is avirulent in chickens. A total of 12 APMV-2 mutants with F protein cleavage site sequences derived from APMV serotypes 1 to 9 were generated. These sites contain from 1 to 5 basic residues. Whereas a number of these cleavage sites are associated with protease dependence and lack of syncytium formation in their respective native viruses, when transferred into the APMV-2 backbone, all of them conferred protease independence, syncytium formation, and increased replication in cell culture. Examination of selected mutants during a pulse-chase experiment demonstrated an increase in F protein cleavage compared to that for wild-type APMV-2. Despite the gains in cleavability, replication, and syncytium formation, analysis of viral pathogenicity in 9-day-old embryonated chicken eggs, 1-day-old chicks, and 2-week-old chickens showed that the F protein cleavage site mutants did not exhibit increased pathogenicity and remained avirulent. These results imply that structural features in addition to the cleavage site play a major role in the cleavability of the F protein and the activity of the cleaved protein. Furthermore, cleavage of the F protein is not a determinant of APMV-2 pathogenicity in chickens.     

Studies on the synthesis of ether-, substituted alkyl-, or aryl-linked C-disaccharide derivatives

A series of ether-, substituted alkyl-, or aryl-linked disaccharide derivatives have been synthesized in relatively good yield and characterized using different spectral techniques including single-crystal X-ray diffraction (XRD). β-Anomeric forms of sugar moiety in these derivatives were identified from ¹H NMR studies. The existence of inter- and intramolecular hydrogen bonding interactions were identified from single-crystal XRD studies.     

Synthesis of Phenoxyacyl-Ethanolamides and Their Effects on Fatty Acid Amide Hydrolase Activity

N-Acylethanolamines (NAEs) are involved in numerous biological activities in plant and animal systems. The metabolism of these lipids by fatty acid amide hydrolase (FAAH) is a key regulatory point in NAE signaling activity. Several active site-directed inhibitors of FAAH have been identified, but few compounds have been described that enhance FAAH activity. Here we synthesized two sets of phenoxyacyl-ethanolamides from natural products, 3-n-pentadecylphenolethanolamide and cardanolethanolamide, with structural similarity to NAEs and characterized their effects on the hydrolytic activity of FAAH. Both compounds increased the apparent V_max of recombinant FAAH proteins from both plant (Arabidopsis) and mammalian (Rattus) sources. These NAE-like compounds appeared to act by reducing the negative feedback regulation of FAAH activity by free ethanolamine. Both compounds added to seedlings relieved, in part, the negative growth effects of exogenous NAE12:0. Cardanolethanolamide reduced neuronal viability and exacerbated oxidative stress-mediated cell death in primary cultured neurons at nanomolar concentrations. This was reversed by FAAH inhibitors or exogenous NAE substrate. Collectively, our data suggest that these phenoxyacyl-ethanolamides act to enhance the activity of FAAH and may stimulate the turnover of NAEs in vivo. Hence, these compounds might be useful pharmacological tools for manipulating FAAH-mediated regulation of NAE signaling in plants or animals.     

Mathematical Modeling of a Carrier-Mediated Transport Process in a Liquid Membrane

An analysis of the reaction diffusion in a carrier-mediated transport process through a membrane is presented. A simple approximate analytical expression of concentration profiles is derived in terms of all dimensionless parameters. Furthermore, in this work we employ the homotopy perturbation method to solve the nonlinear reaction–diffusion equations. Moreover, the analytical results have been compared to the numerical simulation using the Matlab program. The simulated results are comparable with the appropriate theories. The results obtained in this work are valid for the entire solution domain.     

Differential bacterial endophytome in Foc-resistant banana cultivar displays enhanced antagonistic activity against Fusarium oxysporum f.sp. cubense (Foc)

Diverse endophytes with multiple functions exist in different banana cultivars. However, the diversity of cultivable bacterial endophytome that contributes to antifungal activity against Fusarium oxysporum f.sp. cubense (Foc) in resistant and susceptible banana cultivars is mostly unknown. In the present study, we isolated bacterial endophytes from resistant Yengambi KM5 (AAA) and susceptible banana cultivar Ney Poovan (AB) to determine the diversity of cultivable bacterial endophytes. Our study revealed the presence of 56 cultivable bacterial endophytes and 6 nectar-associated bacteria in YKM5 and 31 cultivable bacterial endophytes in Ney Poovan. The identified cultivable bacterial genera in YKM5 included Alcaligenes, Arthrobacter, Azotobacter, Acinetobacter, Agrobacterium, Bacillus, Brucella, Brevundimonas, Brachybacterium, Beijerinckia, Klebsiella, Leclercia, Lysinibacillus, Myroides, Ochrobactrum, Pseudomonas, Rhizobium, Stenotrophomonas, Serratia, and Verticiella. In Ney Poovan, the cultivable endophytic bacterial genera present were Agrobacterium, Bacillus, Bradyrhizobium, Enterobacter, Klebsiella, Lysinibacillus, Micrococcus, Ochrobactrum, Pseudomonas, Rhizobium, and Sphingobium. Thus, the composition and diversity of cultivable endophytic bacterial genera were higher in Foc-resistant YKM5. The antifungal efficacy of bacterial endophytes Brachybacterium paraconglomeratum YEBPT2 (65.5%), Brucella melitensis YEBPS3 (63.3%), Bacillus velezensis YEBBR6 (63.3%), and nectar-associated Bacillus albus YEBN2 (61.1%) from YKM5 showed the highest antifungal activity against Foc, compared with the antifungal activity of endophytes from the susceptible cultivar.     

Humic acid–cetyltrimethylammonium bromide interaction: a fluorimetric study

Synchronous and excitation emission matrix fluorescence (EEMF) characteristics of humic acid–surfactant interaction have been studied. The variation of synchronous and EEMF spectral maxima and intensities with humic acid (HA)–cetyltrimethylammonium bromide (CTAB) composition sensitively reflects the extent of flocculation of HA. It was found that the concentration range for co‐precipitation of HA–CTAB was similar for all concentrations (60 p.p.m., 80 p.p.m. and 100 p.p.m.) of humic acid studied. In the concentration range 60–150 p.p.m. of humic acid, the EEMF maximum is found at 460/540 nm, indicating the presence of ligneous materials. Fluorescence intensity measurement at this contour excitation/emission wavelength (460/540 nm) is suggested as a convenient and a sensitive method for studying the physical state of humic acid in the presence of cationic surfactants. No significant interaction of HA with sodium dodecylsulphate (SDS) and TX‐100 was found. Copyright © 2008 John Wiley & Sons, Ltd.     

Regional aortic differences in atherosclerosis-susceptibility: changes in prostaglandin biosynthesis and cholesterol accumulation in response to desoxycorticosterone (DOCA)-salt induced hypertension

In spontaneously atherosclerosis-susceptible White Carneau pigeons, intimal cushions that appear at birth near the coeliac branch of aorta do not progress into atherosclerotic lesions. However, the area across from the intimal cushion (so called 'lesion area') a) accumulates cholesteryl esters b) synthesizes more PGE2 and c) eventually develops into complicated atherosclerotic plaques. When DOCA-salt hypertension is induced in the pigeons, the 'initimal cushion' area displays a) accumulation of increasing amounts of cholesteryl esters and b) increase in the synthesis of all prostaglandins (particularly PGE2) from C14-arachidonic acid and c) approaches similarity to the 'lesion area' in the magnitude of these changes. These results suggest that under the influence of a risk factor, the 'intimal cushion' can acquire biochemical properties of the atherogenic areas of the aorta.     

Evaluation of Bacillus thuringiensis serovar israelensis produced from a new culture medium for the control of the filariasis vector,Culex quinquefasciatus

The efficacy of Bacillus thuringiensis serovar israelensis (Bti) produced from a culture medium based on chicken feather extract was found to effectively control the filariasis vector, Culex quinquefasciatus for 3 weeks (>90% mortality). The results were on par with Bti produced from the conventional medium.