The effects of disinfectant foam on microbial biofilms

This investigation examined the effects of common aqueous biocides and disinfectant foams derived from them on Pseudomonas aeruginosa biofilms. Biofilms were grown on stainless steel coupons under standardised conditions in a reactor supplemented with low concentrations of organic matter to simulate conditions prevalent in industrial systems. Five-day-old biofilms formed under ambient conditions with continuous agitation demonstrated a low coefficient of variation (5.809%) amongst viable biofilm bacteria from independent trials. Scanning electron microscopy revealed biofilms on coupons with viable biofilm bacteria observed by confocal microscopy. An aqueous solution of a common foaming agent amine oxide (AO) produced negligible effects on bacterial viability in biofilms (p?>?0.05). However, significant biofilm inactivation was noted with aqueous solutions of common biocides (peracetic acid, sodium hypochlorite, sodium ethylenediaminetetraacetic acid) with or without AO (p?<?0.05). Aereation of a mixture of AO with each of these common biocides resulted in significant reductions in the viability of biofilm bacteria (p?<?0.05). In contrast, limited effects were noted by foam devoid of biocides. A relationship between microbial inactivation and the concentration of biocide in foam (ranging from 0.1?–?0.5%) and exposure period were noted (p?<?0.05). Although, lower numbers of viable biofilm bacteria were recovered after treatment with the disinfectant foam than by the cognate aqueous biocide, significant differences between these treatments were not evident (p?>?0.05). In summary, the studies revealed significant biofilm inactivation by biocidal foam prepared with common biocides. Validation of foam disinfectants in controlled trials at manufacturing sites may facilitate developments for clean in place applications. Advantages of foam disinfectants include reductions in the volumes of biocides for industrial disinfection and in their disposal after use.     

Effects of suppression of bone turnover on cortical and trabecular load sharing in the canine vertebral body

The relative biomechanical effects of antiresorptive treatment on cortical thickness vs. trabecular bone microarchitecture in the spine are not well understood. To address this, T-10 vertebral bodies were analyzed from skeletally mature female beagle dogs that had been treated with oral saline (n=8 control) or a high dose of oral risedronate (0.5 mg/kg/day, n=9 RIS-suppressed) for 1 year. Two linearly elastic finite element models (36-μm voxel size) were generated for each vertebral body—a whole-vertebra model and a trabecular-compartment model—and subjected to uniform compressive loading. Tissue-level material properties were kept constant to isolate the effects of changes in microstructure alone. Suppression of bone turnover resulted in increased stiffness of the whole vertebra (20.9%, p=0.02) and the trabecular compartment (26.0%, p=0.01), while the computed stiffness of the cortical shell (difference between whole-vertebra and trabecular-compartment stiffnesses, 11.7%, p=0.15) was statistically unaltered. Regression analyses indicated subtle but significant changes in the relative structural roles of the cortical shell and the trabecular compartment. Despite higher average cortical shell thickness in RIS-suppressed vertebrae (23.1%, p=0.002), the maximum load taken by the shell for a given value of shell mass fraction was lower (p=0.005) for the RIS-suppressed group. Taken together, our results suggest that—in this canine model—the overall changes in the compressive stiffness of the vertebral body due to suppression of bone turnover were attributable more to the changes in the trabecular compartment than in the cortical shell. Such biomechanical studies provide an unique insight into higher-scale effects such as the biomechanical responses of the whole vertebra.     

Subcellular Localization, Partial Purification, and Characterization of a Dynorphin Processing Endopeptidase from Bovine Pituitary

An enzyme capable of cleaving dynorphin B-29 to dynorphin B-13 is present in bovine pituitary, with 40- to 50-fold higher specific activity in the posterior and intermediate lobes than in the anterior lobe. Subcellular fractionation of bovine neurointermediate pituitary shows that this enzyme is present in the peptide-containing secretory vesicles. The enzyme has been purified 2,800-fold from whole bovine pituitaries using ion-exchange and gel filtration chromatography. Purified dynorphin-converting enzyme has a neutral pH optimum, and is subsantially inhibited by the thiol-protease inhibitor p-chloromercuriphenylsulfonic acid, but not by serine or metalloprotease inhibitors. The purified enzyme processes dynorphin B-29 at Arg14, producing both dynorphin B-14 and dynorphin B-13 in a 5:1 ratio. No other cleavages are observed, suggesting that the activity is free from other proteases and is specific for single Arg sequences. Purified enzyme also processes dynorphin A-17 at the single Arg cleavage site, generating both dynorphin A-8 and A-9 in a 7:1 ratio. The tissue distribution, subcellular localization, and substrate specificity of this enzyme are consistent with a physiological role in the processing of dynorphin B-29 and dynorphin A-17, and possibly other peptides, at single Arg residues.     

Genetic engineering approaches to enhance oil content in oilseed crops

Oilseed crops play an important role in the agricultural economy. Apart from being an integral component of human diet and industrial applications, they are also gaining importance as replacement to fossil fuels for meeting the energy needs. The last two decades have been marked by several important events in genetic engineering and identification of gene targets for enhancing seed oil content in oilseed crops, and will aid the successful development of new generation high yielding oil crops. Specifically, genetic engineering has shown real breakthrough in enhancing oil content in oilseed rape, camelina, soybean and maize. Moreover, ongoing research efforts to decipher the possibilities of genetic modifications of key regulators of oil accumulation along with physiological and biochemical studies to understand lipid biosynthesis will set a platform to produce transgenic oilseed crops with enhanced oil content. In this review, we briefly describe different genetic engineering approaches explored by different researchers for enhancing oil content. Further, we discuss a few promising and potential approaches and challenges for engineering oil content in oilseed crops.     

Meiotic restitution in wheat polyhaploids (amphihaploids): a potent evolutionary force

Polyploidy is well recognized as a major force in plant speciation. Among the polyploids in nature, allopolyploids are preponderant and include important crop plants like bread wheat, Triticum aestivum L. (2n = 6x = 42; AABBDD genomes). Allopolyploidy must result through concomitant or sequential events that entail interspecific or intergeneric hybridization and chromosome doubling in the resultant hybrids. To gain insight into the mechanism of evolution of wheat, we extracted polyhaploids of 2 cultivars, Chinese Spring (CS) and Fukuhokomugi (Fuko), of bread wheat by crossing them with maize, Zea mays L. ssp. mays. The derived Ph1-polyhaploids (2n = 3x = 21; ABD) showed during meiosis mostly univalents, which produced first-division restitution (FDR) nuclei that in turn gave rise to unreduced (2n) male gametes with 21 chromosomes. The haploids on maturity set some viable seed. The mean number of seeds per spike was 1.45 +/- 0.161 in CS and 2.3 +/- 0.170 in Fuko. Mitotic chromosome preparations from root tips of the derived plantlets revealed 2n = 42 chromosomes, that is, twice that of the parental polyhaploid, which indicated that they arose by fusion of unreduced male and female gametes formed by the polyhaploid. The Ph1-induced univalency must have produced 2n gametes and hence bilateral sexual polyploidization and reconstitution of disomic bread wheat. These findings highlight the quantum jump by which bread wheat evolved from durum wheat in nature. Thus, bread wheat offers an excellent example of rapid evolution by allopolyploidy. In the induced polyhaploids (ABD) that are equivalent of amphihaploids, meiotic phenomena such as FDR led to regeneration of parental bread wheat, perhaps a simulation of the evolutionary steps that occurred in nature at the time of the origin of hexaploid wheat.     

Regulation of the CYP27B1 5'-flanking region by transforming growth factor-beta in ROS 17/2.8 osteoblast-like cells

The biologically active form of vitamin D, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), regulates osteoblast proliferation and differentiation. Production of 1,25(OH)₂D₃ is catalysed by the enzyme 25-hydroxyvitamin D₃-1-hydroxylase (CYP27B1). Though highly expressed in the kidney, the CYP27B1 gene is also expressed in non-renal tissues including bone. It is hypothesised that local production of 1,25(OH)₂D₃ by osteoblasts plays an autocrine or paracrine role. The aim of this study was to investigate what factors regulate expression of the CYP27B1 gene in osteoblast cells. ROS 17/2.8 osteoblast cells were transiently transfected with plasmid constructs containing the 5′-flanking sequence of the human CYP27B1 gene fused to a luciferase reporter gene. Cells were treated with either parathyroid hormone (PTH), 1,25(OH)₂D₃, transforming growth factor-beta (TGF-β) or insulin-like growth factor-1 (IGF-1) and luciferase activity was measured 24 h later. The results showed that 1,25(OH)₂D₃ did not alter expression of the reporter construct, however treatment with PTH, IGF-1 and TGF-β decreased expression by 18, 53 and 58% respectively. The repressive action of TGF-β was isolated to the region between −531 and −305 bp. These data suggest that expression of the 5′-flanking region for the CYP27B1 gene in osteoblast cells may be regulated differently to that previously described in kidney cells.     

Conservation of NADPH utilization by chorismate synthase and its implications for the evolution of the shikimate pathway

The shikimate pathway is essential for the biosynthesis of aromatic compounds. The seventh and last step is catalysed by chorismate synthase, which has an absolute requirement for reduced FMN in its active site. There are two classes of this enzyme, which are distinguished according to the origin of the reduced cofactor. Monofunctional chorismate synthases sequester it from the cellular environment whereas bifunctional enzymes can generate reduced FMN at the expense of NADPH. These bifunctional enzymes are found in fungi and the ciliated protozoan Euglena gracilis while all bacterial and plant enzymes are monofunctional. In this study, we introduce an in vivo screen, which is based on a chorismate synthase-deficient Saccharomyces cerevisiae strain, allowing the classification of hitherto uncharacterized chorismate synthases. This analysis revealed that bifunctionality is present in the enzymes of protozoan species. In contrast, all bacterial and plant enzymes tested are monofunctional. In addition, we demonstrate that a monofunctional chorismate synthase confers prototrophy in conjunction with a NADPH : FMN oxidoreductase indicating that bifunctionality is required due to the lack of free reduced FMN in fungal and possibly protozoan species. Interestingly, the distribution of bifunctional chorismate synthase concurs with the presence of a pentafunctional enzyme complex.     

Gonadal development and steroid hormone profile of wild caught grey mullet (Mugil cephalus)

The grey mullet Mugil cephalus is one of the popular and fast growing fishes being cultured in tropical and subtropical regions. In the present study, histological observation of gonadal development and corresponding changes in sex steroid levels from different maturity stages of wild caught male and female were studied. In female, testosterone and 17β-estradiol increased with the advancement of maturation and reached peak (17β-estradiol, 323 ± 13 pg/ml; testosterone, 938 ± 7.87 pg/ml) in mature stage, whereas the level of progesterone was maximum (488 ± 4.9 pg/ml) during ripe stage. Vitellogenin level in serum showed a similar trend as 17β-estradiol. In case of male, the testosterone level in serum increased gradually with advancement of maturation and was maximum (1820 ± 40.25 pg/ml) during ripe stage, whereas significant decrease in 17β-estradiol and progesterone was noticed with advancement of maturation. The fundamental information from this investigation would be useful for developing protocol for accelerating maturation and spawning under captive condition.     

Insights from the analysis of conserved motifs and permitted amino acid exchanges in the human, the fly and the worm GPCR clusters

G-protein coupled receptors (GPCRs) belong to biologically important and functionally diverse and largest super family of membrane proteins. GPCRs retain a characteristic membrane topology of seven alpha helices with three intracellular, three extracellular loops and flanking N' and C' terminal residues. Subtle differences do exist in the helix boundaries (TM-domain), loop lengths, sequence features such as conserved motifs, and substituting amino acid patterns and their physiochemical properties amongst these sequences (clusters) at intra-genomic and inter-genomic level (please re-phrase into 2 statements for clarity). In the current study, we employ prediction of helix boundaries and scores derived from amino acid substitution exchange matrices to identify the conserved amino acid residues (motifs) as consensus in aligned set of homologous GPCR sequences. Co-clustered GPCRs from human and other genomes, organized as 32 clusters, were employed to study the amino acid conservation patterns and species-specific or cluster-specific motifs. Critical analysis on sequence composition and properties provide clues to connect functional relevance within and across genome for vast practical applications such as design of mutations and understanding of disease-causing genetic abnormalities.