Effect of relative humidity on the airborne survival of rotavirus SA11.

Rotavirus SA11, suspended in tryptose phosphate broth with 2.5 mg of rhodamine B per ml, was aerosolized (Collison nebulizer) into a rotating drum, and the aerosols were held at 20 +/- 1 degree C with the desired relative humidity (RH). An all-glass impinger with tryptose phosphate broth was used to collect 1-min (5.6-liter) samples of air from the drum. The virus was found to survive best at medium (50 +/- 5%) RH, where its half-life was nearly 40 h. The half-life of the virus at the low (25 +/- 5%) RH level was about 9 h. Even at 72 h of aerosol age, 45 and 21% of the infectious virus remained detectable in the air at the medium and low RH levels, respectively. The high (80 +/- 5%) RH level was found to be the least favorable to the survival of the virus, since 50% of the infectious virus became undetectable within 2 h of aerosolization. In a separate experiment at the midrange RH, 3% of the infectious virus was detectable in the drum air after 223 h (9 days) of aerosol age. Rotaviruses could, therefore, survive in air for prolonged periods, thus making air a possible vehicle for their dissemination.     

Assessment of the influence of intrinsic environmental and geographical factors on the bacterial ecology of pit latrines

Improving the rate and extent of faecal decomposition in basic forms of sanitation such as pit latrines would benefit around 1.7 billion users worldwide, but to do so requires a major advance in our understanding of the biology of these systems. As a critical first step, bacterial diversity and composition was studied in 30 latrines in Tanzania and Vietnam using pyrosequencing of 16S rRNA genes, and correlated with a number of intrinsic environmental factors such as pH, temperature, organic matter content/composition and geographical factors. Clear differences were observed at the operational taxonomic unit, family and phylum level in terms of richness and community composition between latrines in Tanzania and Vietnam. The results also clearly show that environmental variables, particularly substrate type and availability, can exert a strong structuring influence on bacterial communities in latrines from both countries. The origins and significance of these environmental differences are discussed. This work describes the bacterial ecology of pit latrines in combination with inherent latrine characteristics at an unprecedented level of detail. As such, it provides useful baseline information for future studies that aim to understand the factors that affect decomposition rates in pit latrines.     

Investigation of Plasmonic Bandgap for 1D Exposed and Buried Metallic Gratings

Plasmonics - A simulation study for the opening of plasmonic bandgap (PBG) with control over it by varying the slit width (SW) for exposed and buried 1D metallic gratings has been reported by using...     

Repenins A–D,four new antioxidative coumarinolignoids from Duranta repens Linn.

Phytochemical investigations on the CHCl₃-soluble fraction of the whole plant of Duranta repens Linn. led to the isolation of four new coumarinolignoids, Repenins A–D (1–4), along with the known coumarinolignoids, cleomiscosin A (5) and durantin A (6). Their structures were determined by modern spectroscopic analysis including 1D and 2D NMR techniques and chemical studies. The compounds (1–6) showed potent antioxidative scavenging activity against DPPH radicals, with IC₅₀ values in the range 0.420–0.625 mM. Repenin B (2) displayed the strongest scavenging potential with IC₅₀ values of (0.420 mM).     

Comparison of the airborne survival of calf rotavirus and poliovirus type 1 (Sabin) aerosolized as a mixture

A mixture of a cell culture-adapted strain (C-486) of calf rotavirus and poliovirus type 1 (Sabin) was prepared in tryptose phosphate broth containing 0.1% uranine (physical tracer) and antifoam at a final concentration of 0.001%. By using a six-jet Collison nebulizer, the mixture was aerosolized into a 300-liter stainless-steel rotating (4 rpm) drum. The temperature of the air inside the drum was kept at 20 +/- 1 degrees C, and the virus aerosols were held at the following three levels of relative humidity (RH): low (30 +/- 5%), medium (50 +/- 5%), and high (80 +/- 5%). An all-glass impinger, containing 10.0 ml of tryptose phosphate broth with antifoam, was used to collect samples of air from the drum. Both viruses were propagated and quantitated in MA-104 cells. The calf rotavirus was found to survive well at mid-range RH, where 60% of the infectious virus could be detected even after 24 h of virus aerosolization. At the low RH, the half-life of the infectious rotavirus was ca. 14 h. On the other hand, no infectious poliovirus could be recovered from the drum air at the low and medium RH. At the high RH, more than 50% of the infectious rotavirus became undetectable within 90 min of aerosolization. In contrast to this, the half-life of the poliovirus at the high RH was about 10 h. These data, based on the aerosolization of virus mixtures, therefore suggest that there is a pronounced difference in the way RH influences the airborne survival of these two types of viruses held under identical experimental conditions.     

Molecular,biochemical and bioassay based evidence of lower allelopathic potential in genetically modified rice

This study examines allelopathic potential of genetically modified rice. The experiment was conducted on two isogenic lines Bacillus thuringiensis (Bt) and non-Bacillus thuringiensis (non-Bt). Both isogenic lines have same allelopathic ability before insect feeding and after limited insect feeding (Spodoptera litura) non-Bt rice genotype demonstrates more allelopathic potential. The S. litura cannot feed Bt rice genotype. The role of shoot herbivory in allelopathic induction is further supported when Bt plants also exhibited higher allelopathic potential after insect regurgitant application to the damaged leaves. Allelopathic potential was assessed through several methods after treatments of mechanical damage, insect feeding and insect regurgitant application to damaged rice leaves. Rhizosphere soil and leaf leachates of non-Bt rice cultivar exhibited higher allelopathic potential on lettuce and barnyard grass after herbivore feeding. Enzyme activities (PAL and C4H) responsible for biosynthesis of phenolic compounds and their concentration were significantly higher in non-Bt plant after herbivore feeding and attain the same level in Bt plants after insect regurgitant application to damaged leaves. Similarly, genes (OsPAL and OsCYC1) responsible for biosynthesis of allelopathic compounds showed high expression in non-Bt plants after herbivore feeding. Our results indicate that herbivore feeding enhance rice allelopathic potential and no insect feeding as incase of Bt plants may reduce allelopathic potential of genetically modified rice.     

The Expression Pattern of microRNAs in Granulosa Cells of Subordinate and Dominant Follicles during the Early Luteal Phase of the Bovine Estrous Cycle

This study aimed to investigate the miRNA expression patterns in granulosa cells of subordinate (SF) and dominant follicle (DF) during the early luteal phase of the bovine estrous cycle. For this, miRNA enriched total RNA isolated from granulosa cells of SF and DF obtained from heifers slaughtered at day 3 and day 7 of the estrous cycle was used for miRNAs deep sequencing. The results revealed that including 17 candidate novel miRNAs, several known miRNAs (n = 291–318) were detected in SF and DF at days 3 and 7 of the estrous cycle of which 244 miRNAs were common to all follicle groups. The let-7 families, bta-miR-10b, bta-miR-26a, bta-miR-99b and bta-miR-27b were among abundantly expressed miRNAs in both SF and DF at both days of the estrous cycle. Further analysis revealed that the expression patterns of 16 miRNAs including bta-miR-449a, bta-miR-449c and bta-miR-222 were differentially expressed between the granulosa cells of SF and DF at day 3 of the estrous cycle. However, at day 7 of the estrous cycle, 108 miRNAs including bta-miR-409a, bta-miR-383 and bta-miR-184 were differentially expressed between the two groups of granulosa cell revealing the presence of distinct miRNA expression profile changes between the two follicular stages at day 7 than day 3 of the estrous cycle. In addition, unlike the SF, marked temporal miRNA expression dynamics was observed in DF groups between day 3 and 7 of the estrous cycle. Target gene prediction and pathway analysis revealed that major signaling associated with follicular development including Wnt signaling, TGF-beta signaling, oocyte meiosis and GnRH signaling were affected by differentially expressed miRNAs. Thus, this study highlights the miRNA expression patterns of granulosa cells in subordinate and dominant follicles that could be associated with follicular recruitment, selection and dominance during the early luteal phase of the bovine estrous cycle.     

Bacterial diversity along a 2600 km river continuum

The bacterioplankton diversity in large rivers has thus far been under‐sampled despite the importance of streams and rivers as components of continental landscapes. Here, we present a comprehensive dataset detailing the bacterioplankton diversity along the midstream of the Danube River and its tributaries. Using 16S rRNA‐gene amplicon sequencing, our analysis revealed that bacterial richness and evenness gradually declined downriver in both the free‐living and particle‐associated bacterial communities. These shifts were also supported by beta diversity analysis, where the effects of tributaries were negligible in regards to the overall variation. In addition, the river was largely dominated by bacteria that are commonly observed in freshwaters. Dominated by the acI lineage, the freshwater SAR11 (LD12) and the Polynucleobacter group, typical freshwater taxa increased in proportion downriver and were accompanied by a decrease in soil and groundwater‐affiliated bacteria. Based on views of the meta‐community and River Continuum Concept, we interpret the observed taxonomic patterns and accompanying changes in alpha and beta diversity with the intention of laying the foundation for a unified concept for river bacterioplankton diversity.