Brevibacillus as a biological tool: a short review

The significance of Brevibacillus has been documented scientifically in the published literature and commercially in heterologous recombinant protein catalogs. Brevibacillus is one of the most widespread genera of Gram-positive bacteria, recorded from the diverse environmental habitats. The high growth rate, better transformation efficiency by electroporation, availability of shuttle vectors, production of negligible amount of extracellular protease, and the constitutive expression of heterologous proteins make some strains of this genus excellent laboratory models. Regarding biotechnological applications, this genus continues to be a source of various enzymes of great biotechnological interest due to their ability to biodegrade low density polyethylene, ability to act as a candidate bio-control agent, and more recently acknowledged as a tool for the overexpression. This article reviews the properties of Brevibacillus spp. as better biological tools with varied applications.     

In vitro biotechnological advancements in Malabar nut (Adhatoda vasica Nees): Achievements,status and prospects

Adhatoda vasica Nees, belonging to family Acanthaceae, is a well-known medicinal plant. It is endorsed for its pyrroloquinazoline alkaloids and its derivatives, such as vasicine and vasicinone. Germinating A. vasica seeds is a tedious task; on that account, vegetative propagation is the preferred method for its multiplication. For rapid and large-scale multiplication, germplasm conservation as well as secondary metabolites production, in vitro culture of A. vasica was preferred over conventional propagation by several researchers; however, some major applications of this tissue culture technique are still awaiting to undergo extensive research. The present review, for the first time, illustrates all the major achievements associated with in vitro regeneration of A. vasica, reported till date and highlights the future prospects.     

Ageing of chloroplasts in vitro — III. Comparison of the effects of ageing in vitro and senescence on the red absorption band and primary photochemical reactions of sunflower chloroplasts

A comparison of changes in absorption properties and electron transport activities of chloroplasts ageing in vivo and in vitro is made. Chloroplasts from sunflower leaves senescing in vivo during 7 days in dark do not show a blue shift of the red absorption band; in contrast, the shift becomes apparent within 24 h of in vitro ageing of isolated organelles. Photosynthetic activity by chloroplasts is lost much faster during in vitro than in vivo ageing. During in vitro ageing, the rate of degradation of thylakoid membranes as characterised by the shift in the red absorption band and loss in Hill reaction is further accelerated in chloroplasts isolated from dark-induced senescing leaves, suggesting the influence of the in vivo status of the chloroplasts on their in vitro stability.Abbreviations DCPIP 2,6-dichlorophenol indophenol - PSI Photosystem I - Chl Chlorophyll     

Life cycle assessment of densified wheat straw pellets in the Canadian Prairies

Purpose  

Densification, a process used to manufacture pellets in order to increase biomass bulk density, plays a crucial role in the economics of biomass utilization. The Canadian Prairies produce large quantities of agricultural residues each year, in particular wheat straw. This study performs life cycle assessment of wheat straw pellets by evaluating environmental effects of the entire pellet production system comprising feedstock production (on-farm wheat straw production), harvesting, baling, transportation, and the industrial processing involving drying, grinding, pelletizing, and packing in the densification plant. The effects of each process on the environmental performance of wheat straw pellets were investigated.     

The F0F1-ATP Synthase Complex Contains Novel Subunits and Is Essential for Procyclic Trypanosoma brucei

The mitochondrial F₀F₁ ATP synthase is an essential multi-subunit protein complex in the vast majority of eukaryotes but little is known about its composition and role in Trypanosoma brucei, an early diverged eukaryotic pathogen. We purified the F₀F₁ ATP synthase by a combination of affinity purification, immunoprecipitation and blue-native gel electrophoresis and characterized its composition and function. We identified 22 proteins of which five are related to F₁ subunits, three to F₀ subunits, and 14 which have no obvious homology to proteins outside the kinetoplastids. RNAi silencing of expression of the F₁ α subunit or either of the two novel proteins showed that they are each essential for the viability of procyclic (insect stage) cells and are important for the structural integrity of the F₀F₁-ATP synthase complex. We also observed a dramatic decrease in ATP production by oxidative phosphorylation after silencing expression of each of these proteins while substrate phosphorylation was not severely affected. Our procyclic T. brucei cells were sensitive to the ATP synthase inhibitor oligomycin even in the presence of glucose contrary to earlier reports. Hence, the two novel proteins appear essential for the structural organization of the functional complex and regulation of mitochondrial energy generation in these organisms is more complicated than previously thought.     

Role of uridylate-specific exoribonuclease activity in Trypanosoma brucei RNA editing

Editing of mitochondrial mRNAs in kinetoplastid protozoa occurs by a series of enzymatic steps that insert and delete uridylates (U's) as specified by guide RNAs (gRNAs). The characteristics of the 3" exonuclease activity that removes the U's following cleavage during deletion editing were determined by using an in vitro precleaved deletion assay that is based on ATPase subunit 6 pre-mRNA and gA6[14] gRNA. The exonuclease in partially purified editing complexes is specific for U's. The specificity occurs in the absence of gRNA, but its activity is enhanced by the presence of gRNA. The 3" pre-mRNA fragment enhances the specificity, but not the efficiency, of U removal. The activity is sensitive to the 5" phosphate of the 3" fragment, which is not required for U removal. The ability of the 3" U's to base pair with purines in the gRNA protects them from removal, suggesting that the U-specific 3" exonuclease (exoUase) is specific for U's which are not base paired. ExoUase is stereospecific and cannot remove (R_p)α-thio-U. The specificity of the exoUase activity thus contributes to the precision of RNA editing.