Heat shock response: hsp70 in environmental monitoring

Heat shock proteins (Hsps) are a ubiquitous feature of cells in which these proteins cope with stress-induced denaturation of other proteins. Among the different families of Hsps, the 70 kDa family (hsp70) is the most highly conserved and has been most extensively studied. Apart from their primary role in cellular defense under stress condition, a number of studies in recent years have shown the immense potential of hsp70 in pollution monitoring using even transgenic approach both in vivo and in vitro. This article reviews the recent developments in the widespread application of hsp70 in environmental risk assessment.     

Use of complex media for the production of scleroglucan by Sclerotium rolfsii MTCC 2156

Submerged fermentation was carried out for the production of scleroglucan by Sclerotium rolfsii MTCC 2156 using complex media, such as coconut water, sugarcane molasses and sugarcane juice at 28+/-2 degrees C and 180 rpm for 72 h. Sugarcane juice gave maximum scleroglucan production of 23.87 g/l as compared to 12.58 and 18.45 g/l with coconut water and sugarcane molasses, respectively. Utilization of these substrates would be ecologically sound and economically advantageous.     

Optimization of protein-based volumetric optical memories and associative processors by using directed evolution

The potential use of proteins in device applications has advanced in large part due to significant advances in the methods and procedures of protein engineering, most notably, directed evolution. Directed evolution has been used to tailor a broad range of enzymatic proteins for pharmaceutical and industrial applications. Thermal stability, chemical stability, and substrate specificity are among the most common phenotypes targeted for optimization. However, in vivo screening systems for photoactive proteins have been slow in development. A high-throughput screening system for the photokinetic optimization of photoactive proteins would promote the development of protein-based field-effect transistors, artificial retinas, spatial light modulators, photovoltaic fuel cells, three-dimensional volumetric memories, and optical holographic processors. This investigation seeks to optimize the photoactive protein bacteriorhodopsin (BR) for volumetric optical and holographic memories. Semi-random mutagenesis and in vitro screening were used to create and analyze nearly 800 mutants spanning the entire length of the bacterio-opsin (bop) gene. To fully realize the potential of BR in optoelectronic environments, future investigations will utilize global mutagenesis and in vivo screening systems. The architecture for a potential in vivo screening system is explored in this study. We demonstrate the ability to measure the formation and decay of the red-shifted O-state within in vivo colonies of Halobacterium salinarum, and discuss the implications of this screening method to directed evolution. These authors contributed equally to this work.     

Calcineurin Subunits A and B Interact to Regulate Growth and Asexual and Sexual Development in Neurospora crassa

Calcineurin is a calcium/calmodulin dependent protein phosphatase in eukaryotes that consists of a catalytic subunit A and a regulatory subunit B. Previous studies in the filamentous fungus Neurospora crassa had suggested that the catalytic subunit of calcineurin might be an essential protein. We generated N. crassa strains expressing the A (cna-1) and B (cnb-1) subunit genes under the regulation of P_tcu-1, a copper-responsive promoter. In these strains, addition of bathocuproinedisulfonic acid (BCS), a copper chelator, results in induction of cna-1 and cnb-1, while excess Cu²⁺ represses gene expression. Through analysis of these strains under repressing and inducing conditions, we found that the calcineurin is required for normal growth, asexual development and female fertility in N. crassa. Moreover, we isolated and analyzed cnb-1 mutant alleles generated by repeat-induced point mutation (RIP), with the results further supporting roles for calcineurin in growth and fertility in N. crassa. We demonstrated a direct interaction between the CNA-1 and CNB-1 proteins using an assay system developed to study protein-protein interactions in N. crassa.     

Anorectal volume–pressure relations,contraction work,and flow during defecation

Biomechanics and Modeling in Mechanobiology - Fecobionics is an integrated device that has shown promise for assessment of anorectal function. We used a wireless Fecobionics prototype to visualize...     

Physical and physiological impacts of different foam control strategies during a process involving hydrophobic substrate for the lipase production by Yarrowia lipolytica

The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyl oleate) have to be investigated. The key factor governing the lipase yield is the intensification of the oxygen transfer rate, considering the fact that Y. lipolytica is a strict aerobe. However, considering the nature of the substrate and the capacity for protein excretion and biosurfactant production of Y. lipolytica, intensification of oxygen transfer rate is accompanied by an excessive formation of foam. Two different foam control strategies have thus been implemented: a classical chemical foam control strategy and a mechanical foam control (MFM) based on the Stirring As Foam Disruption principle. The second strategy allows foam control without any modifications of the physico-chemical properties of the broth. However, the MFM system design induced the formation of a persistent foam layer in the bioreactor. This phenomenon has led to the segregation of microbial cells between the foam phase and the liquid phase in the case of the bioreactors operated with MFM control, and induced a reduction at the level of the lipase yield. More interestingly, flow cytometry experiments have shown that the residence time of microbial cells in the foam phase tends to induce a dimorphic transition which could potentially explain the reduction of lipase excretion.     

Genome Degradation in Brucella ovis Corresponds with Narrowing of Its Host Range and Tissue Tropism

Brucella ovis is a veterinary pathogen associated with epididymitis in sheep. Despite its genetic similarity to the zoonotic pathogens B. abortus, B. melitensis and B. suis, B. ovis does not cause zoonotic disease. Genomic analysis of the type strain ATCC25840 revealed a high percentage of pseudogenes and increased numbers of transposable elements compared to the zoonotic Brucella species, suggesting that genome degradation has occurred concomitant with narrowing of the host range of B. ovis. The absence of genomic island 2, encoding functions required for lipopolysaccharide biosynthesis, as well as inactivation of genes encoding urease, nutrient uptake and utilization, and outer membrane proteins may be factors contributing to the avirulence of B. ovis for humans. A 26.5 kb region of B. ovis ATCC25840 Chromosome II was absent from all the sequenced human pathogenic Brucella genomes, but was present in all of 17 B. ovis isolates tested and in three B. ceti isolates, suggesting that this DNA region may be of use for differentiating B. ovis from other Brucella spp. This is the first genomic analysis of a non-zoonotic Brucella species. The results suggest that inactivation of genes involved in nutrient acquisition and utilization, cell envelope structure and urease may have played a role in narrowing of the tissue tropism and host range of B. ovis.