Bacteriophage MS2 displays unreported capsid variability assembling T = 4 and mixed capsids

Bacteriophage MS2 is a positive-sense, single-stranded RNA virus encapsulated in an asymmetric T = 3 pseudo-icosahedral capsid. It infects Escherichia coli through the F-pilus, in which it binds through a maturation protein incorporated into its capsid. Cryogenic electron microscopy has previously shown that its genome is highly ordered within virions, and that it regulates the assembly process of the capsid. In this study, we have assembled recombinant MS2 capsids with non-genomic RNA containing the capsid incorporation sequence, and investigated the structures formed, revealing that T = 3, T = 4 and mixed capsids between these two triangulation numbers are generated, and resolving structures of T = 3 and T = 4 capsids to 4 Å and 6 Å respectively. We conclude that the basic MS2 capsid can form a mix of T = 3 and T = 4 structures, supporting a role for the ordered genome in favouring the formation of functional T = 3 virions.     

Benchmarking environmental performance of electric insulator supply chain in India using life cycle assessment

Purpose

This study aims at finding the environmental impacts generated by an electric disk insulator supply chain, used for the distribution of electricity by an open wire system, through a case study. This study also aims at benchmarking the environmental impacts of an electric insulator manufacturing process by taking ideal condition of zero waste as reference.

Methods

Cradle-to-grave life cycle assessment (LCA) has been carried out by following the guidelines provided in ISO 14040 series standards and using Umberto NXT software. ReCiPe endpoint and ReCiPe midpoint impact assessment methodologies have been used to calculate environmental impacts under various categories. The primary data has been collected from a medium-scale manufacturer of electric disk insulators located at Bikaner in north-west India. The secondary data has been taken from ecoinvent 3.0 database and literature. The environmental impacts using endpoint assessment (ecosystem quality, human health, and resources) and midpoint assessment (climate change, fossil depletion, human toxicity, metal depletion, ozone depletion, terrestrial acidification, and water depletion) categories have been computed. Finally, the results are compared and benchmarked against the ideal zero waste condition using three different production scenarios. The limitation of this study is that the data has been collected only from one manufacturer and its supply chain.

Results and discussion

It has been found that the use of steel, electricity, and fuel; transportation of product; and disposal of water generate high environmental impacts in the supply chain. It has also been found that in the electric disk insulator supply chain, the raw material extraction phase has the highest environmental impacts followed by manufacturing, disposal, transportation, and installation phases. This study has also found that benchmark scenario “B” (zero waste condition) is environmentally more efficient in comparison to scenario “A” (actual recycling condition) and scenario “C” (maximum waste condition).

Conclusions

This study has identified that raw materials, resources, and processes in the supply chain of an electric disk insulator manufacturing unit are responsible for the environmental damage. The various manufacturing processes and installation of the electric disk insulators are similar for all manufacturers except the machinery efficiency and the generated waste. This study provides environmental impacts associated with an electric disk insulator manufacturing process under zero waste or ideal conditions (scenario B). These results are used as a benchmark to compare environmental performance of electric disk insulator supply chain operating under actual conditions.

     

Genetic engineering of indica rice with AtDREB1A gene for enhanced abiotic stress tolerance

Plant Cell, Tissue and Organ Culture (PCTOC) - Adventitious root (AR) culturing is an effective approach for obtaining bioactive compounds from the endangered plant species of Oplopanax elatus...     

Genetic and Genomic Resources of Small Millets

Small millets are very promising agricultural entity to ensure global food security. They gained remarkable importance in agriculture due to their resilience to climatic changes and increasing demand for nutritious food and feed. The genetic variability in the core and mini-core germplasm of small millets was characterized for nutritional composition and capacity to tolerate abiotic stresses that can be infused in breeding programs. Other than the foxtail millet, availability of genomic information in small millets is far below the mark for use in marker-assisted breeding and other genetic improvement programs. The genome sequence of foxtail millet has recently triggered a plethora of post-genomic analysis and envisaged foxtail millet as a model organism for the C₄ grasses and bioenergy research. Recent developments in the next-generation sequencing technologies enabled us, with the simultaneous discovery of high-throughput markers and multiplexed genotyping of germplasm, to speedup marker-assisted breeding. In this context, an in-depth analysis of the wealth of diverse germplasm resources and future perspectives of integrating genomics in genome-wide marker-trait association and breeding in small millets is worthy.     

Biodegradable poly(vinyl alcohol)-polyethylenimine nanocomposites for enhanced gene expression in vitro and in vivo

Use of cationic polymers as nonviral gene vectors has several limitations such as low transfection efficiency, high toxicity, and inactivation by serum. In this study, varying amounts of low molecular weight branched polyethylenimine 1.8 kDa (bPEI 1.8) were introduced on to a neutral polymer, poly(vinyl alcohol) (PVA), to bring in cationic charge on the resulting PVA-PEI (PP) nanocomposites. We rationalized that by introducing bPEI 1.8, buffering and condensation properties of the proposed nanocomposites would result in improved gene transfer capability. A series of PVA-PEI (PP) nanocomposites was synthesized using well-established epoxide chemistry and characterized by IR and NMR. Particle size of the PP/DNA complexes ranged between 120 to 135 nm, as determined by dynamic light scattering (DLS), and DNA retardation assay revealed efficient binding capability of PP nanocomposites to negatively charged nucleic acids. In vitro transfection of PP/DNA complexes in HEK293, HeLa, and CHO cells revealed that the best working formulation in the synthesized series, PP-3/DNA complex, displayed ~2-50-fold higher transfection efficiency than bPEIs (1.8 and 25 kDa) and commercial transfection reagents. More importantly, the PP/DNA complexes were stable over a period of time, along with their superior transfection efficiency in the presence of serum compared to serum-free conditions, retaining the nontoxic property of low molecular weight bPEI. The in vivo administration of PP-3/DNA complex in Balb/c mice showed maximum gene expression in their spleen. The study demonstrates the potential of PP nanocomposites as promising nonviral gene vectors for in vivo applications.     

TDZ-induced direct shoot organogenesis and somatic embryogenesis on cotyledonary node explants of lentil (Lens culinaris Medik.)

An efficient and simple procedure for inducing high frequency direct shoot organogenesis and somatic embryogenesis in lentil from cotyledonary node explants (without both the cotyledons) in response to TDZ alone is reported. TDZ at concentration lower than 2.0 μM induced shoot organogenesis whereas at higher concentration (2.5–15 μM) it caused a shift in regeneration from shoot organogenesis to somatic embryogenesis. The cotyledonary node and seedling cultures developed only shoots even at high concentrations of BAP and TDZ, respectively. TDZ at 0.5 and 5.0 μM was found to be optimal for inducing an average of 4–5 shoots per cotyledonary node in 93 % of the cultures and 55 somatic embryos in 68 % of the cultures, respectively. The somatic embryos were germinated when transferred to lower TDZ concentration (0.5–1.0 μM). The shoots were rooted on MS basal medium containing 2.5 μM IBA. The plantlets were obtained within 8 weeks from initiation of culture and were morphologically similar to seed-raised plants. The possible role of stress in thidiazuron induced somatic embryogenesis is discussed.Key words: Thidiazuron, Lens culinaris, Somatic embryogenesis, Organogenesis     

Peroxidase and catalase changes during in vitro adventitious shoot organogenesis from hypocotyls of Albizia odoratissima L.f. (Benth)

Hypocotyls of Albizia odoratissima cultured on shoot induction medium (MS medium with 7.5 μM BAP and 0.5 μM NAA) showed adventitious shoot organogenesis under light with 16 h photoperiod. Similar cultures under total darkness produced non-morphogenic calli. The changes in the specific peroxidase and catalase activity, total protein content and acidic isoperoxidase pattern were compared between the culture showing shoot organogenesis and culture producing non-morphogenic calli. It was found that in vitro shoot bud differentiation is accompanied by an increase of the specific activities of peroxidase and catalase in culture kept under light. In parallel with the above changes the total protein content reached to the maximum level and also a new isoperoxidase (P10) expressed on the 21st day in cultures kept under light. Conversely, culture producing non-morphogenic calli underwent a reverse change in specific peroxidase activity. This change in antioxidant enzyme activities corresponds to the histological observation of shoot bud differentiation in cultures kept under light.     

Antisense expression of a gene encoding a calcium-binding protein in transgenic tobacco leads to altered morphology and enhanced chlorophyll

Entamoeba histolytica contains a novel calcium-binding protein like calmodulin, which was discovered earlier, and we have reported the presence of its homologue(s) and a dependent protein kinase in plants. To understand the functions of these in plants, a cDNA encoding a calcium-binding protein isolated from Entamoeba histolytica (EhCaBP) was cloned into vector pBI121 in antisense orientation and transgenic tobacco plants were raised. These plants showed variation in several phenotypic characters, of which two distinct features, more greenness and leaf thickness, were inherited in subsequent generations. The increase in the level of total chlorophyll in different plants ranged from 60% to 70%. There was no major change in chloroplast structure and in the protein level of D1, D2, LHCP and RuBP carboxylase. These morphological changes were not seen in antisense calmodulin transgenic tobacco plants, nor was the calmodulin level altered in EhCaBP antisense plants. The results of this paper have been granted US Patent No. 6,791,009.     

Comparative genome analysis of Solanum lycopersicum and Solanum tuberosum

Solanum lycopersicum and Solanum tuberosum are agriculturally important crop species as they are rich sources of starch, protein, antioxidants, lycopene, beta-carotene, vitamin C, and fiber. The genomes of S. lycopersicum and S. tuberosum are currently available. However the linear strings of nucleotides that together comprise a genome sequence are of limited significance by themselves. Computational and bioinformatics approaches can be used to exploit the genomes for fundamental research for improving their varieties. The comparative genome analysis, Pfam analysis of predicted reviewed paralogous proteins was performed. It was found that S. lycopersicum proteins belong to more families, domains and clans in comparison with S. tuberosum. It was also found that mostly intergenic regions are conserved in two genomes followed by exons, intron and UTR. This can be exploited to predict regions between genomes that are similar to each other and to study the evolutionary relationship between two genomes, leading towards the development of disease resistance, stress tolerance and improved varieties of tomato.