The 3MRA Risk Assessment Framework—A Flexible Approach for Performing Multimedia,Multipathway, and Multireceptor Risk Assessments Under Uncertainty

A flexible framework for conducting nationwide multimedia, multipathway and multireceptor risk assessments (3MRA) under uncertainty was developed to estimate protective chemical concentration limits in a source area. The framework consists of two components: risk assessment and uncertainty analysis. The risk component utilizes linked source, fate/transport, exposure and risk assessment models to estimate the risk exposures for the receptors of concern. Both human and ecological receptors are included in the risk assessment framework. The flexibility of the framework is based on its ability to address problems varying in spatial scales from site-specific to regional and even national levels; and its ability to accommodate varying types of source, fate/transport, exposure and risk assessment models. The uncertainty component of the 3MRA framework is based on a two-stage Monte Carlo methodology. It allows the calculation of uncertainty in risk estimates, and the incorporation of the effects of uncertainty on the determination of regulatory concentration limits as a function of variability and uncertainty in input data, as well as potential errors in fate and transport and risk and exposure models. The framework can be adapted to handle a wide range of multimedia risk assessment problems. Two examples are presented to illustrate its use, and to demonstrate how regulatory decisions can be structured to incorporate the uncertainty in risk estimates.     

Association of a Distinct Begomovirus and a Betasatellite with Leaf Curl Symptoms in Pedilanthus tithymaloides

Pedilanthus tithymaloides (Redbird flower) is an ornamental shrub that occasionally exhibits leaf curl and enation symptoms in Pakistan. Symptoms were shown to be associated with a monopartite begomovirus and a betasatellite. The complete nucleotide sequence of the begomovirus was found to be 2764 nucleotides in length and have the highest nucleotide sequence identity to a begomovirus previously isolated from tomato (90.3% nucleotide sequence identity), followed by Radish leaf curl virus (86.3%). The complete betasatellite sequence was determined to be 1358 nucleotides in length and has the highest sequence identity (97%) with Tobacco leaf curl betasatellite . The analysis shows the begomovirus associated with leaf curl disease of Pedilanthus to be a distinct and previously unreported begomovirus for which the name Pedilanthus leaf curl virus (PedLCV) is proposed. This virus is one of an increasing number of monopartite begomoviruses shown to be associated with a betasatellite.     

Concentration dependent growth/non-growth linked kinetics of endosulfan biodegradation by <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

The rates of biodegradation of endosulfan by P. aeruginosa were determined with different initial endosulfan concentrations (10, 50, 100, 150, 200 and 250 mg l⁻¹) and different growth linked kinetic models were fitted at these concentrations. At 10 mg endosulfan l⁻¹, Monod no growth model was well fitted. Monod with growth model described the biodegradation pattern at an initial concentration of 50, 100 and 150 mg endosulfan l⁻¹. Significant increases of P. aeruginosa MN2B14 density in broth culture during incubation further support this result. Conversely, zero order kinetic model was well fitted into the biodegradation data if initial endosulfan concentration was ≥200 mg endosulfan l⁻¹. The kinetics of endosulfan biodegradation by P. aeruginosa MN2B14 in liquid broth was highly dependent upon its initial concentration. The results of this study could be employed for predicting the persistence of endosulfan in water environment containing P. aeruginosa as an endosulfan degrading bacterium.     

Studies on the production of nigerloxin using agro-industrial residues by solid-state fermentation

Nigerloxin, a new and potent lipoxygenase inhibitor, was discovered in our laboratory through solid-state fermentation of wheat bran by Aspergillus niger V. Teigh (MTCC-5166). The aim of this study is to investigate the possibility of using different agro-industrial residues as nutritional supplements along with wheat bran to enhance the production of nigerloxin. Nigerloxin produced by SSF was quantified spectrophotometrically at 292 nm. The results indicate that the inhibitor production was influenced by the type of solid substrate supplemented, moisture content, pH and size of the inoculum. Individually optimized supplements were tested in different combinations to determine their effects on nigerloxin production. A twofold increase in the production of nigerloxin (4.9 ± 0.3 mg gds⁻¹) was achieved by supplementing wheat bran with 10% w/w sweet lemon peel and 5% v/w methanol at optimized process parameters, that is, an initial moisture content of 65% v/w and incubation period of 6 days with an initial inoculum size of 2 ml (8 × 10⁵ spores gds⁻¹). Nigerloxin production was stable between pH of 4 and 5.     

Mitochondrial Genome Dynamics in Plants and Animals: Convergent Gene Fusions of a MutS Homologue

Mitochondrial processes influence a broad spectrum of physiological and developmental events in higher eukaryotes, and their aberrant function can lead to several familiar disease phenotypes in mammals. In plants, mitochondrial genes directly influence pollen development and the occurrence of male sterility in natural plant populations. Likewise, in animal systems evidence accumulates to suggest important mitochondrial functions in spermatogenesis and reproduction. Here we present evidence for a convergent gene fusion involving a MutS-homologous gene functioning within the mitochondrion and designated Msh1. In only plants and soft corals, the MutS homologue has fused with a homing endonuclease sequence at the carboxy terminus of the protein. However, the endonuclease domains in the plants and the soft corals are members of different groups. In plants, Msh1 can influence mitochondrial genome organization and male sterility expression. Based on parallels in Msh1 gene structure shared by plants and corals, and their similarities in reproductive behavior, we postulate that this convergent gene fusion might have occurred in response to coincident adaptive pressures on reproduction. [Reviewing Editor: Dr. Deborah Charlesworth]     

Primordial germ cell-mediated chimera technology produces viable pure-line Houbara bustard offspring: potential for repopulating an endangered species

Background

The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring.

Methodology/Principal Findings

Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue containing gonadal primordial germ cells (gPGCs) was injected into White Leghorn chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male chimeric embryos, of which 35 chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric chicken testis were assessed by PCR with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected chicken embryos showed the presence of donor Houbara cells. A total of 302 semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these eight roosters were used to artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which were fertile. One egg hatched as a male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Houbara derived from a chimeric rooster.

Conclusion

This study demonstrates for the first time that Houbara gPGCs can migrate, differentiate and eventually give rise to functional sperm in the chimeric chicken testis. This approach may provide a promising tool for propagation and conservation of endangered avian species that cannot breed in captivity.     

Molecular Confirmation of Intraspecific Tomato (<Emphasis Type="Italic">Solanum lycopersicum)</Emphasis> Hybrids and Their Evaluation Against Late Blight and Cucumber Mosaic Virus

Tomato is one of the most consumed vegetables in the world. Diseases are the number one concern in the development of high-yield and disease-resistant tomato hybrids which is the foremost priority of breeders. Present study was conducted (1) to develop DNA-based markers for genetic confirmation of tomato F₁ hybrids, (2) to utilize sequenced characterized amplified region (SCAR) marker linked to the Ph-3 gene for Phytophthora infestans resistance in tomato and (3) to evaluate male and female parental genotypes and their F₁ hybrids against late blight (LB) and cucumber mosaic virus (CMV). For molecular studies, 58 previously reported markers including RAPDs (10), SCAR (01), EST-SSR (01) and SSR (46) were applied. The SCAR marker clearly differentiated the LB3 and LB4 from Roma and T-1359 and provided evidence for Ph-3 gene. The SCAR marker was able to confirm the Ph-3 gene in the hybrids Roma × LB4, Roma × LB3, Riogrande × LB2, Riogrande × LB3 and Roma × LB7. Out of several tested primers, SSR-22 proved useful for genetic confirmation of F₁ hybrid TMS1 × Money Maker (MM). For LB, tested hybrids/genotypes were ranked as susceptible to highly susceptible with different infection percentage (IP). However, the pace of symptom development was slower in hybrid Rio × LB2, 45% IP after 10 days of inoculation compared with 85% disease in one of the parent genotypes (Riogrande). None of the tested genotypes was found resistant; however, TMS1 responded as tolerant against CMV using mechanical inoculation. Under natural field conditions, TMS1 was found resistant while hybrids TMS1 × Naqeeb and TMS1 × MM were tolerant where as others were found to be susceptible. In conclusion, all tomato hybrids were genetically confirmed using DNA-based markers. SCAR marker was useful for marker-assisted confirmation of the Ph-3 gene in parental lines and hybrids; however, this gene was unable to provide protection against the local population of P. infestans.     

Protective effect of esculin against prooxidant aflatoxin B1-induced nephrotoxicity in mice

The study was designed to investigate the protective effect of esculin against pro-oxidant aflatoxin B₁ (AFB₁)-induced nephrotoxicity in mice. In this study toxicity was developed by oral administration of AFB₁ at a dose of 66.60 μg/kg bw/day for 90 days in male Swiss albino mice. Esculin (150 mg/kg bw/0.2 ml/day) and standard compound ascorbic acid (300 mg/kg bw/0.2 ml/day) was given after 30 min of AFB₁ administration for 90 days. Protective efficacy was assessed by measuring the levels of lipid peroxidation (LPO) and non-enzymatic antioxidants such as reduced glutathione (GSH) and also by measuring activities of enzymatic antioxidants such as glutathione peroxidase (GPX), glutathione-S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) in kidney. Results were analysed at the 30^th, 60^th and 90^th day of the daily treatments, which showed a decrease in the level of LPO and an increase in the levels of enzymatic and non-enzymatic antioxidants. The protective effect of esculin was further proved by histopathological findings as it exhibited regenerative activities in mice renal tubules against AFB₁-induced nephrotoxicity. The results obtained clearly demonstrate that the protective efficacy of esculin against pro-oxidant AFB₁-induced nephrotoxicity in mice might be due to its antioxidants and free radical scavenging properties.     

Absolute Configuration of Oplopanone Derivatives From Serphidium stenocephalum: ECD Spectra of Acyclic Ketones With Front‐Octant Contributions

The electronic circular dichroism (ECD) spectra of two sesquiterpenoids ( 1 and 2 ) related to oplopanone, obtained from a methanolic extract of the plant Serphidium stenocephalum (Artemisia stenocephala), were measured and reproduced by means of time‐dependent density functional theory (TDDFT) calculations, establishing their absolute configuration. The application of ketone octant rule for carbonyl n‐π* ECD band to compounds 1 and 2 , which include an acyclic carbonyl group, was critically assessed. The peculiar oplopanone skeleton makes a straightforward application of the octant rule impossible, because of the uncertainty related to the shape of the so‐called third nodal surface separating front and back octants. The various group contributions to the carbonyl n‐π* ECD band were estimated with TDDFT calculations on selected molecular models obtained by consecutive dissections from 1 . Chirality 26:39–43, 2013. © 2013 Wiley Periodicals, Inc.