Genetic analysis and characterization of a Caulobacter crescentus mutant defective in membrane biogenesis.

A mutant of Caulobacter crescentus has been isolated which has an auxotrophic requirement for unsaturated fatty acids or biotin for growth on medium containing glucose as the carbon source. This mutant exhibits a pleiotropic phenotype which includes (i) the auxotrophic requirement, (ii) cell death in cultures attempting to grow on glucose in the absence of fatty acids or biotin, and (iii) a major change in the outer membrane protein composition before cell death. This genetic lesion did not appear to affect directly a fatty acid biosynthetic reaction because fatty acid and phospholipid syntheses were found to continue in the absence of supplement. Oleic acid repressed fatty acid biosynthesis and induced fatty acid degradation in the wild-type parent, AE5000 . The mutant strain, AE6000 , was altered in both of these regulatory functions. The AE6000 mutant also showed specific inhibition of the synthesis of outer membrane and flagellar proteins. Total phospholipid, DNA, RNA, and protein syntheses were unaffected. The multiple phenotypes of the AE6000 mutant were found to cosegregate and to map between hclA and lacA on the C. crescentus chromosome. The defect in this mutant appears to be associated with a regulatory function in membrane biogenesis and provides evidence for a direct coordination of membrane protein synthesis and lipid metabolism in C. crescentus.     

Occurrence of crystals in vascular cambium

Summary Crystals are of common occurrence in plant tissues and considered to be waste products resulting from active metabolism of plant cells. They mostly occur in ray and vertical parenchyma of wood and bark of angiosperm trees and often develop in tissues which soon cease to be functional. While studying the annual rhythm of cambial activity in two species of theVerbenaceae, Tectona grandis (Rao andDave 1981) andGmelina arborea (Dave andRao 1982), crystals of calcium oxalate have been observed in ray initials (Figs. 1–10). The crystals were identified as calcium oxalate after a convincing chemical behaviour towards dilute (10%) acetic, hydrochloric, and sulphuric acids. They appear colorless when viewed with brightfield illumination (Fig. 3), and show birefringence in polarized light (Figs. 1 and 6). Radial, tangential, and transverse sections of 10–15 m thick were used to study the crystals in polarized light with a Carl Zeiss Axiomat microscope.     

Use of Polyvinyl Alcohol as a Solubility-Enhancing Polymer for Poorly Water Soluble Drug Delivery (Part 1)

Polyvinyl alcohol (PVAL) has not been investigated in a binary formulation as a concentration-enhancing polymer owing to its high melting point/high viscosity and poor organic solubility. Due to the unique attributes of the KinetiSol® dispersing (KSD) technology, PVAL has been enabled for this application and it is the aim of this paper to investigate various grades for improvement of the solubility and bioavailability of poorly water soluble active pharmaceutical ingredients. Solid amorphous dispersions were created with the model drug, itraconazole (ITZ), at a selected drug loading of 20%. Polymer grades were chosen with variation in molecular weight and degree of hydroxylation to determine the effects on performance. Differential scanning calorimetry, powder X-ray diffraction, polarized light microscopy, size exclusion chromatography, and dissolution testing were used to characterize the amorphous dispersions. An in vivo pharmacokinetic study in rats was also conducted to compare the selected formulation to current market formulations of ITZ. The 4-88 grade of PVAL was determined to be effective at enhancing solubility and bioavailability of itraconazole.     

Changes in habitat availability for outmigrating juvenile salmon (Oncorhynchus spp.) following estuary restoration

The restoration of the Nisqually River Delta (Washington, U.S.A.) represents one of the largest efforts toward reestablishing the ecosystem function and resilience of modified habitat in the Puget Sound, particularly for anadromous salmonid species. The opportunity for outmigrating salmon to access and benefit from the expansion of available tidal habitat can be quantified by several physical attributes, which are related to the ecological and physiological responses of juvenile salmon. We monitored a variety of physical parameters to measure changes in opportunity potential from historic, pre‐restoration, and post‐restoration habitat conditions at several sites across the delta. These parameters included channel morphology, water quality, tidal elevation, and landscape connectivity. We conducted fish catch surveys across the delta to determine if salmon was utilizing restored estuary habitat. Overall major channel area increased 42% and major channel length increased 131% from pre‐ to post‐restoration conditions. Furthermore, the results of our tidal inundation model indicated that major channels were accessible up to 75% of the time, as opposed to 30% pre‐restoration. Outmigrating salmon utilized this newly accessible habitat as quickly as 1 year post‐restoration. The presence of salmon in restored tidal channels confirmed rapid post‐restoration increases in opportunity potential on the delta despite habitat quality differences between restored and reference sites.     

Use of Polyvinyl Alcohol as a Solubility Enhancing Polymer for Poorly Water-Soluble Drug Delivery (Part 2)

The KinetiSol® Dispersing (KSD) technology has enabled the investigation into the use of polyvinyl alcohol (PVAL) as a concentration enhancing polymer for amorphous solid dispersions. Our previous study revealed that the 88% hydrolyzed grade of PVAL was optimal for itraconazole (ITZ) amorphous compositions with regard to solid-state properties, non-sink dissolution performance, and bioavailability enhancement. The current study investigates the influence of molecular weight for the 88% hydrolyzed grades of PVAL on the properties of KSD processed ITZ:PVAL amorphous dispersions. Specifically, molecular weights in the processable range of 4 to 18 mPa · s were evaluated and the 4-88 grade provided the highest AUC dissolution profile. Amorphous dispersions at 10, 20, 30, 40, and 50% ITZ drug loads in PVAL 4-88 were also compared by dissolution performance. Analytical tools of diffusion-ordered spectroscopy and Fourier transform infrared spectroscopy were employed to understand the interaction between drug and polymer. Finally, results from a 30-month stability test of a 30% drug loaded ITZ:PVAL 4-88 composition shows that stable amorphous dispersions can be achieved. Thus, this newly enabled polymer carrier can be considered a viable option for pharmaceutical formulation development for solubility enhancement.KEY WORDS: amorphous solid dispersion, itraconazole, polyvinyl alcohol, PVAL, solubility enhancement     

Correlates of distribution and nesting success in a Welsh upland Eurasian Curlew Numenius arquata population

Capsule: Habitat structure and composition explained spatial variation in breeding distribution and nesting success in a declining upland Eurasian Curlew Numenius arquata population in North Wales.

Aims: To identify environmental correlates of Curlew breeding distribution, nesting success and change in distribution.

Methods: Thirty random 1?km squares stratified by historical population trend were surveyed for Curlew density and nesting success, and habitat- and predation-related variables in a landscape containing agriculturally improved farmland, and moorland that was partly protected and subject to grazing reductions for nature conservation. Analyses tested for associations between Curlew measures and environmental variables.

Results: Curlew breeding density declined by 29% between 1994 and 2008, and was highest in squares comprising a mixture of moorland and agriculturally improved farmland, and in squares with lower vegetation density and higher cover of Nardus stricta (characteristic of rough grazing). Nesting success was positively associated with cover of Trichophorum germanicum (characteristic of mire). Vegetation density was lower than average in squares with the highest Curlew densities, while in the protected area vegetation density was higher than average.

Conclusion: Habitat and vegetation variables influenced Curlew distribution and nesting success in North Wales, largely in line with previous results but with no evidence for predator-related influences. Habitat condition for Curlew in the protected area could probably be increased through targeted increases in grazing alongside the protection of priority habitats.     

Application of monoclonal antibodies in quantifying fungal growth dynamics during aerobic spoilage of silage

Proliferation of filamentous fungi following ingress of oxygen to silage is an important cause of dry matter losses, resulting in significant waste. In addition, the production of mycotoxins by some filamentous fungi poses a risk to animal health through mycotoxicosis. Quantitative assessment of fungal growth in silage, through measurement of ergosterol content, colony-forming units or temperature increase is limiting in representing fungal growth dynamics during aerobic spoilage due to being deficient in either representing fungal biomass or being able to identify specific genera. Here, we conducted a controlled environment aerobic exposure experiment to test the efficacy of a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) to detect the proliferation of fungal biomass in six silage samples. We compared this to temperature which has been traditionally deployed in such experiments and on-farm to detect aerobic deterioration. In addition, we quantified ergosterol, a second marker of fungal biomass. After 8 days post-aerobic exposure, the ergosterol and ELISA methods indicated an increase in fungal biomass in one of the samples with a temperature increase observed after 16 days. A comparison of the methods with Pearson's correlation coefficient showed a positive association between temperature and ergosterol and both markers of fungal biomass. This work indicates that the technology has potential to be used as an indicator of microbial degradation in preserved forage. Consequently, if it developed as an on-farm technique, this could inform forage management decisions made by farmers, with the goal of decreasing dry matter losses, improving resource and nutrient efficiency and reducing risks to animal health.     

Anthropogenic and Ecological Drivers of Amphibian Disease (Ranavirosis)

Ranaviruses are causing mass amphibian die-offs in North America, Europe and Asia, and have been implicated in the decline of common frog (Rana temporaria) populations in the UK. Despite this, we have very little understanding of the environmental drivers of disease occurrence and prevalence. Using a long term (1992-2000) dataset of public reports of amphibian mortalities, we assess a set of potential predictors of the occurrence and prevalence of Ranavirus-consistent common frog mortality events in Britain. We reveal the influence of biotic and abiotic drivers of this disease, with many of these abiotic characteristics being anthropogenic. Whilst controlling for the geographic distribution of mortality events, disease prevalence increases with increasing frog population density, presence of fish and wild newts, increasing pond depth and the use of garden chemicals. The presence of an alternative host reduces prevalence, potentially indicating a dilution effect. Ranavirosis occurrence is associated with the presence of toads, an urban setting and the use of fish care products, providing insight into the causes of emergence of disease. Links between occurrence, prevalence, pond characteristics and garden management practices provides useful management implications for reducing the impacts of Ranavirus in the wild.     

How do Meat Scarcity and Bushmeat Commodification Influence Sharing and Giving among Forest Foragers? A View from the Central African Republic

Meat sharing is a societal norm among hunter-gatherer societies that provisions families and supports social networks. Meat is also a valued resource central to traditional barter exchange. Ethnographic research often cites prey scarcity and commodification as two factors reducing traditional meat transactions among indigenous Central African foragers. We present quantitative data based on ethnographic observations of foragers in the Central African Republic that show that neither scarcity nor commodification eliminates sharing. The bushmeat market is associated with changes in village demographic structure that limits the distribution of meat among extended kin. Although cash generated from the sale of forest products reduces the need for inter-ethnic barter, gift giving and exchange maintain these important relationships. Our data show the persistence of traditional meat transactions and identify potential changes in demographic structure as a less obvious outcome of the bushmeat trade that can have extended consequences for forager populations.