Ozone as a selective disinfectant for nonaseptic fungal cultivation on corn-processing wastewater

Treatment of wet corn-milling wastewater with filamentous fungi was investigated as a means of obtaining fungal biomass as an additional byproduct. Competitive bacterial growth is a common problem during this nonaseptic treatment process. Selective disinfection with ozone was evaluated for eliminating bacterial populations during fungal cultivation. Three laboratory-scale continuous flow aerated reactors were operated under nonaseptic conditions at 38 degrees C, hydraulic retention time of 8h and pH of 4. The bacterial population was reduced by one log with respect to the control when ozone was dosed at a concentration above 47+/-2mg/L. An ozone dosage of about 57mg/L was found to be most effective in improving both fungal biomass production and soluble chemical oxygen demand (SCOD) removal (up to 90%). Fungal biomass concentration increased from c. 1.45g/L (control) to c. 1.75g/L at a 57-mg/L ozone dosage. Higher and lower dosages of ozone resulted in poorer fungal growth and lower SCOD removal.     

Foraging behaviour of planktivorous fish in artificial vegetation: the effects on swimming and feeding

In the littoral zones of lakes, aquatic macrophytes produce considerable structural variation that can provide protection to prey communities by hindering predator foraging activity. The swimming and feeding behaviour of a planktivore, Pseudorasbora parva(Cyprinidae) on its prey (Daphnia pulex) was studied in a series of laboratory experiments with varying densities (0, 350, 700, 1400, 2100 and 2800 stems m^–2) of simulated submerged vegetation. Prey availability was varied from 0.5, 1.0, 2.0, 5.0, 10.0 and 25.0 prey l^–1. As the stem density increased, the predator's swimming speed and the number of prey captured decreased relative to feeding in open water. A good relation existed between the number of successful prey captures and swimming speed with the average stem distance to fish body length ratio (D). An abrupt reduction in feeding and swimming was recorded when D was reduced to values less than one.     

Analysis of an intraspecific RIL population uncovers genomic segments harbouring multiple QTL for seed relevant traits in lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> L.)

Improving seed related traits remains key objective in lentil breeding. In recent years, genomic resources have shown great promise to accelerate crop improvement. However, limited genomic resources in lentil greatly restrict the use of genomics assisted breeding. The present investigation aims to build an intraspecific genetic linkage map and identify the QTL associated with important seed relevant traits using 94 recombinant inbreds (WA 8649090 × Precoz). A total of 288 polymorphic DNA markers including simple sequence repeat (SSR), inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) were assayed on mapping population. The resultant genetic linkage map comprised 220 loci spanning 604.2 cM of the lentil genome, with average inter-marker distance of 2.74 cM. QTL mapping in this RIL population uncovered a total of 18 QTL encompassing nine major and nine minor QTL. All major QTL were detected for seed related traits viz., seed diameter (SD), seed thickness (ST), seed weight (SW) and seed plumpness (SP) across two locations. A considerable proportion of the phenotypic variation (PV) was accounted to these QTL. For instance, one major QTL on LG5 controlling SW (QTL 15) explained 50% PV in one location, while the same QTL accounted for 34.18% PV in other location. Importantly, the genomic region containing multiple QTL for different seed traits was mapped to a 17-cM region on LG5. The genomic region harbouring QTL for multiple traits opens up exciting opportunities for genomics assisted improvement of lentil.     

Structure/function analyses of human serum paraoxonase (HuPON1) mutants designed from a DFPase-like homology model

Human serum paraoxonase (HuPON1) is a calcium-dependent enzyme that hydrolyzes esters, including organophosphates and lactones, and exhibits anti-atherogenic properties. A few amino acids have been shown to be essential for the enzyme's arylesterase and organophosphatase activities. Until very recently, a three-dimensional model was not available for HuPON1, so functional roles have not been assigned to those residues. Based on sequence-structure alignment studies, we have folded the amino acid sequence of HuPON1 onto the sixfold beta-propeller structure of squid diisopropylfluorophosphatase (DFPase). We tested the validity of this homology model by circular dichroism (CD) spectroscopy and site-directed mutagenesis. Consistent with predictions from the homology model, CD data indicated that the structural composition of purified HuPON1 consists mainly of beta-sheets. Mutants of HuPON1 were assayed for enzymatic activity against phenyl acetate and paraoxon. Substitution of residues predicted to be important for substrate binding (L69, H134, F222, and C284), calcium ion coordination (D54, N168, N224, and D269), and catalytic mechanism of HuPON1 (H285) led to enzyme inactivation. Mutants F222Y and H115W exhibited substrate-binding selectivity towards phenyl acetate and paraoxon, respectively. The homology model presented here is very similar to the recently obtained PON1 crystal structure, and has allowed identification of several residues within the enzyme active site.     

Mathematical and computational modelling of spatio-temporal signalling in rod phototransduction

Rod photoreceptors are activated by light through activation of a cascade that includes the G protein-coupled receptor rhodopsin, the G protein transducin, its effector cyclic guanosine monophosphate (cGMP) phosphodiesterase and the second messengers cGMP and Ca2+. Signalling is localised to the particular rod outer segment disc, which is activated by absorption of a single photon. Modelling of this cascade has previously been performed mostly by assumption of a well-stirred cytoplasm. We recently published the first fully spatially resolved model that captures the local nature of light activation. The model reduces the complex geometry of the cell to a simpler one using the mathematical theories of homogenisation and concentrated capacity. The model shows that, upon activation of a single rhodopsin, changes of the second messengers cGMP and Ca2+ are local about the particular activated disc. In the current work, the homogenised model is computationally compared with the full, non-homogenised one, set in the original geometry of the rod outer segment. It is found to have an accuracy of 0.03% compared with the full model in computing the integral response and a 5200-fold reduction in computation time. The model can reconstruct the radial time-profiles of cGMP and Ca2+ in the interdiscal spaces adjacent to the activated discs. Cellular electrical responses are localised near the activation sites, and multiple photons sufficiently far apart produce essentially independent responses. This leads to a computational analysis of the notion and estimate of 'spread' and the optimum distribution of activated sites that maximises the response. Biological insights arising from the spatio-temporal model include a quantification of how variability in the response to dim light is affected by the distance between the outer segment discs capturing photons. The model is thus a simulation tool for biologists to predict the effect of various factors influencing the timing, spread and control mechanisms of this G protein-coupled, receptor-mediated cascade. It permits ease of simulation experiments across a range of conditions, for example, clamping the concentration of calcium, with results matching analogous experimental results. In addition, the model accommodates differing geometries of rod outer segments from different vertebrate species. Thus it represents a building block towards a predictive model of visual transduction.     

Sequence analysis of the long arm of rice chromosome 11 for rice–wheat synteny

The DNA sequence of 106 BAC/PAC clones in the minimum tiling path (MTP) of the long arm of rice chromosome 11, between map positions 57.3 and 116.2 cM, has been assembled to phase 2 or PLN level. This region has been sequenced to 10× redundancy by the Indian Initiative for Rice Genome Sequencing (IIRGS) and is now publicly available in GenBank. The region, excluding overlaps, has been predicted to contain 2,932 genes using different software. A gene-by-gene BLASTN search of the NCBI wheat EST database of over 420,000 cDNA sequences revealed that 1,143 of the predicted rice genes (38.9%) have significant homology to wheat ESTs (bit score 100). Further BLASTN search of these 1,143 rice genes with the GrainGenes database of sequence contigs containing bin-mapped wheat ESTs allowed 113 of the genes to be placed in bins located on wheat chromosomes of different homoeologous groups. The largest number of genes, about one-third, mapped to the homoeologous group 4 chromosomes of wheat, suggesting a common evolutionary origin. The remaining genes were located on wheat chromosomes of different groups with significantly higher numbers for groups 3 and 5. Location of bin-mapped wheat contigs to chromosomes of all the seven homoeologous groups can be ascribed to movement of genes (transpositions) or chromosome segments (translocations) within rice or the hexaploid wheat genomes. Alternatively, it could be due to ancient duplications in the common ancestral genome of wheat and rice followed by selective elimination of genes in the wheat and rice genomes. While there exists definite conservation of gene sequences and the ancestral chromosomal identity between rice and wheat, there is no obvious conservation of the gene order at this level of resolution. Lack of extensive colinearity between rice and wheat genomes suggests that there have been many insertions, deletions, duplications and translocations that make the synteny comparisons much more complicated than earlier thought. However, enhanced resolution of comparative sequence analysis may reveal smaller conserved regions of colinearity, which will facilitate selection of markers for saturation mapping and sequencing of the gene-rich regions of the wheat genome.     

The Influence of Structural Complexity on Fish–zooplankton Interactions: A Study Using Artificial Submerged Macrophytes

Aquatic macrophytes produce considerable structural variation within the littoral zone and as a result the vegetation provides refuge to prey communities by hindering predator foraging activities. The behavior of planktivorous fish Pseudorasbora parva (Cyprinidae) and their zooplankton prey Daphnia pulex were quantified in a series of laboratory experiments with artificial vegetation at densities of 0, 350, 700, 1400, 2100 and 2800 stemsm^–2. Swimming speeds and foraging rates of the fish were recorded at different prey densities for all stem densities. The foraging efficiency of P. parva decreased significantly with increasing habitat complexity. This decline in feeding efficiency was related to two factors: submerged vegetation impeded swimming behavior and obstructed sight while foraging. This study separated the effects of swimming speed variation and of visual impairment, both due to stems, that led to reduced prey–predator encounters and examined how the reduction of the visual field volume may be predicted using a random encounter model.     

Selection and evaluation ofAzospirillum brasilense strains growing at a sub-optimum temperature in rhizocoenosis with wheat

FourteenAzospirillum brasilense strains growing at a sub-optimum temperature were selected based on their ability to grow and carry out plant growth promoting activities at 22°C. The strains were tested for their response to inoculation in wheat (two popular cultivars, HD2285 and WH547, under sterile conditions) crop using sterile and nonsterile rooting medium. Significant increase in plant growth parameters was observed: the overall response to inoculation was better in cultivar HD 2285. Based on their performance under sterile conditions, 4 strains were selected and compared under nonsterile conditions with strain sensitive to a sub-optimum temperature in pots using wheat variety HD2285. The strains capable of growing at the sub-optimum temperature can colonize the wheat endorhizosphere efficiently and improve the plant growth and yield as compared to sensitive strain; a 25–27% increase in grain yield was found on inoculating two selected strains compared to NO ₃ ^- control.     

Placenta Stem/Stromal Cell–Derived Extracellular Vesicles for Potential Use in Lung Repair

Many acute and chronic lung injuries are incurable and rank as the fourth leading cause of death globally. While stem cell treatment for lung injuries is a promising approach, there is growing evidence that the therapeutic efficacy of stem cells originates from secreted extracellular vesicles (EVs). Consequently, EVs are emerging as next‐generation therapeutics. While EVs are extensively researched for diagnostic applications, their therapeutic potential to promote tissue repair is not fully elucidated. By housing and delivering tissue‐repairing cargo, EVs refine the cellular microenvironment, modulate inflammation, and ultimately repair injury. Here, the potential use of EVs derived from two placental mesenchymal stem/stromal cell (MSC) lines is presented; a chorionic MSC line (CMSC29) and a decidual MSC cell line (DMSC23) for applications in lung diseases. Functional analyses using in vitro models of injury demonstrate that these EVs have a role in ameliorating injuries caused to lung cells. It is also shown that EVs promote repair of lung epithelial cells. This study is fundamental to advancing the field of EVs and to unlock the full potential of EVs in regenerative medicine.