Specific energy requirement for compacting corn stover

Corn stover is a major crop residue for biomass conversion to produce chemicals and fuels. One of the problems associated with the supply of corn stover to conversion plants is the delivery of feedstock at a low cost. Corn stover has low bulk density and it is difficult to handle. In this study, chopped corn stover samples were compacted in a piston cylinder under three pressure levels (5, 10, 15 MPa) and at three moisture content levels (5%, 10%, 15% (wb)) to produce briquettes. The total energy requirement to compress and extrude briquette ranged from 12 to 30 MJ/t. The briquette density ranged from 650 to 950 kg/m3 increasing with pressure. Moisture content had also a significant effect on briquette density, durability and stability. Low moisture stover (5-10%) resulted in denser, more stable and more durable briquettes than high moisture stover (15%).     

3β-Hydroxylup-20(29)-ene-27,28-dioic acid dimethyl ester,a novel natural product from Plumbago zeylanica inhibits the proliferation and migration of MDA-MB-231 cells

Plumbago zeylanica, a traditional Indian herb is being used for the therapy of rheumatism and has been approved for anti-tumor activity. However, the molecular mechanisms involved in the biological action are not very well understood. In this study, the anti-invasive activities of P. zeylanica methanolic extract (PME) and pure compound 3β-hydroxylup-20(29)-ene-27,28-dioic acid (PZP) isolated from it are investigated in vitro. PME and PZP were noted to have the ability to induce apoptosis as assessed by flow cytometry. Further, the molecular mechanism of apoptosis induced by PME and PZP was found by the loss of mitochondrial membrane potential with the down regulation of Bcl-2, increased expression of Bad, release of cytochrome c, activation of caspase-3 and cleavage of PARP leading to DNA fragmentation. Importantly, both PME and PZP were observed to suppress MDA-MB-231 cells adhesion to the fibronectin-coated substrate and also inhibited the wound healing migration and invasion of MDA-MB-231 cells through the reconstituted extracellular matrix. Gelatin zymography revealed that PME and PZP decreased the secretion of matrix metalloproteinases-2 (MMP-2) and metalloproteinases-9 (MMP-9). Interestingly both PME and PZP exerted an inhibitory effect on the protein levels of p-PI3K, p-Akt, p-JNK, p-ERK1/2, MMP-2, MMP-9, VEGF and HIF-1α that are consistent with the observed anti-metastatic effect. Collectively, these data provide the molecular basis of the anti-proliferative and anti-metastatic effects of PME and PZP.     

Non-specific immune response and disease resistance induced by Siegesbeckia glabrescens against Vibrio parahaemolyticus in Epinephelus bruneus

The immunomodulatory effect of Siegesbeckia glabrescens extract-supplementation diets on innate immune response and disease resistance of kelp grouper, Epinephelus bruneus against Vibrio parahaemolyticus at weeks 1, 2, and 4 is reported. The serum lysozyme activity was significantly enhanced with any enriched diet from weeks 1-4 when compared to control diet (0%). The alternative complement haemolytic activities significantly were enhanced with all enriched diets on weeks 2 and 4 whereas the cellular reactive oxygen species (ROS) was significantly enhanced only with 1.0% and 2.0% diets. The reactive nitrogen intermediate (RNI) value was significantly enhanced with any enriched diet on weeks 2 and 4, but on first week it did not differ from control. The myeloperoxidase (MPO) production significantly increased with 1.0% and 2.0% diets from second week onwards; with other enriched diets the increase manifested on fourth week; but during first week it did not vary from that of the control with any enriched diet. The protection in terms of cumulative mortality was the least being 25% and 20% when fed with 1.0% and 2.0% diets. The present results indicate that feeding kelp grouper with S. glabrescens extract enriched diet at 1.0% and 2.0% levels significantly enhance the immunological parameters, increase the disease resistance and minimize the cumulative mortality in E. bruneus against V. parahaemolyticus.     

Targeting and sensing cancer cells with ZnO nanoprobes in vitro

A new class of zinc oxide quantum dots (ZnO QDs) was investigated as nanoprobes for targeting cancer cells in vitro. ZnO nanoparticles were synthesized using conventional sol–gel method and encapsulated using trimethoxy aminopropyl silane. Transferrin, the ligand targeting the cancer cells, was conjugated to the ZnO QDs. In vitro imaging studies using MDA-MB-231 showed the biocompatible ZnO nanoprobe selectively binding to the cell surface receptor and internalizing through receptor-mediated endocytosis. Time-lapsed photobleaching studies indicate the ZnO QDs to be resistant to photobleaching, making them suitable for long term imaging purpose. Investigation of the ZnO nanoprobe as a platform for sensitive bioassays indicates that it can be used as an alternative fluoroprobe for cancer cell targeting and sensing applications.     

Densification of Thermally Treated Energy Cane and Napier Grass

Densification of thermally treated energy crops by torrefaction is required to increase the bulk density and to reduce the handling, transport, and storage cost for bioenergy applications. In this study, we investigated the densification characteristics of thermally treated energy cane and napier grass grown on marginal lands at various applied forces and binder levels. The addition of starch (0, 10, and 15%) and lignosulfonate (0, 5, and 10%) was examined to enhance the strength and durability of raw and torrefied briquettes, respectively. Although the use of starch binder relatively increased the bulk density, it did not improve the hardness and durability of untreated energy crop briquettes. The addition of 10% lignosulfonate binder increased the torrefied briquette density of up to 11% for energy cane and up to 38% for napier grass and decreased the compression energy by up to 35% for both samples. Moreover, the hardness (compressive resistance) was tripled, and the durability was relatively improved for both torrefied briquettes. The increase in applied force not only increased the bulk density but also increased the specific energy required for densification. However, there was no substantial change in hardness and durability when the compression force was increased from 15 to 20 kN for all samples. In overall, densification of thermally treated energy crops is required, and the quality of the briquettes can be improved by the use of appropriate binders for efficient handling, transport, and storage.     

Cleansing the long-term micropropagated triploid watermelon cultures from covert bacteria and field testing the plants for clonal fidelity and fertility during the 7–10 year period in vitro

The study was aimed primarily at cleansing the in vitro-decline displaying long-term micropropagated triploid watermelon ‘Arka Manik’ cultures from covert bacteria and their further field testing. Disinfectant treated shoots showed endophytic survival but to a lesser extent in shoot-tips. Culturing the NaOCl (5 min) treated shoot-tips on filter paper bridges in liquid watermelon medium containing single antibiotic (gentamycin (Gm), amoxycillin (Ax) or cefazolin (Cz) at 50, 250, 500 or 1000 mg l⁻¹) for 1 month followed by repeated indexing of medium and tissue for two-four subculture passages facilitated the cleansing of cultures with 12.5% recovery as monitored for 2 years. Partial bleaching damage by NaOCl, phytotoxicity to higher levels of antibiotics, poor growth response in the initial sucrose-free medium and rampant hyperhydricity came in the way of a higher recovery. The effectiveness of the above approach was ascertained after back inoculating clean cultures with a mixture of Gram-positive and Gram-negative bacteria yielding 30, 45 and 35% clean cultures in Gm, Ax and Cz (250 mg l⁻¹ for 1 month) treatments, respectively in modified medium compared with 10% recovery after mere HgCl₂ surface sterilization. The results indicated that antibiotic treatment was essential but not its choice, and extended culture-indexing subsequent to disinfection or antibiotic treatment was crucial in identifying clean stocks. Cleansed cultures, showed restoration of growth but a drop in rooting. Most of the in vitro cultures appeared normal and true-to-type during the 7–10 year period in vitro but a small proportion of bacteria-harboring stocks displayed ‘epigenetic variations’. Acclimatized plants and those in the field also appeared true-to-type but for a minor proportion derived from bacteria-harboring stocks. Field-plants which originated from bacteria-freed stocks after 9 years of continuous culturing were normal and fertile validating the possibility of keeping treasured cultures in vitro for long periods if covert contaminants are checked.     

Differentially Evolved Genes of Salmonella Pathogenicity Islands: Insights into the Mechanism of Host Specificity in Salmonella

Background

The species Salmonella enterica (S. enterica) includes many serovars that cause disease in avian and mammalian hosts. These serovars differ greatly in their host range and their degree of host adaptation. The host specificity of S. enterica serovars appears to be a complex phenomenon governed by multiple factors acting at different stages of the infection process, which makes identification of the cause/s of host specificity solely by experimental methods difficult.

Methodology/Principal Findings

In this study, we have employed a molecular evolution and phylogenetics based approach to identify genes that might play important roles in conferring host specificity to different serovars of S. enterica. These genes are ‘differentially evolved’ in different S. enterica serovars. This list of ‘differentially evolved’ genes includes genes that encode translocon proteins (SipD, SseC and SseD) of both Salmonella pathogenicity islands 1 and 2 encoded type three secretion systems, sptP, which encodes an effector protein that inhibits the mitogen-activated protein kinase pathway of the host cell, and genes which encode effector proteins (SseF and SifA) that are important in placing the Salmonella-containing vacuole in a juxtanuclear position.

Conclusions/Significance

Analysis of known functions of these ‘differentially evolved genes’ indicates that the products of these genes directly interact with the host cell and manipulate its functions and thereby confer host specificity, at least in part, to different serovars of S. enterica that are considered in this study.