Mulberry Leaf Metabolism under High Temperature Stress

Effects of high temperature on the activity of photosynthetic enzymes and leaf proteins were studied in mulberry (Morus alba L. cv. BC2-59). A series of experiments were conducted at regular intervals (120, 240 and 360 min) to characterize changes in activities of ribulose-1,5-bisphosphate carboxylase (RuBPC) and sucrose phosphate synthase (SPS), photosystem 2 (PS 2) activity, chlorophyll (Chl), carotenoid (Car), starch, sucrose (Suc), amino acid, free proline, protein and nucleic acid contents in leaves under high temperature (40 °C) treatments. High temperature markedly reduced the activities of RuBPC and SPS in leaf extracts. Chl content and PS 2 activity in isolated chloroplasts were also affected by high temperature, particularly over 360 min treatment. Increased leaf temperature affected sugar metabolism through reductions in leaf starch content and sucrose-starch balance. While total soluble protein content decreased under heat, total amino acid content increased. Proline accumulation (1.5-fold) was noticed in high temperature-stressed leaves. A reduction in the contents of foliar nitrogen and nucleic acids (DNA and RNA) was also noticed. SDS-PAGE protein profile showed few additional proteins (68 and 85 kDa) in mulberry plants under heat stress compared to control plants. Our results clearly suggest that mulberry plants are very sensitive to high temperature with particular reference to the photosynthetic carbon metabolism.     

Comparative population growth and life table demography of the rotifer Asplanchna girodi at different prey (Brachionus calyciflorus and Brachionus havanaensis) (Rotifera) densities

Population growth and life table demography of the predatory rotifer A. girodi using spineless Brachionus calyciflorus and spined Brachionus havanaensis as prey at densities of 1, 2, 4 and 8 ind. ml^–1 at 25°C were studied. Regardless of the prey species, the population of A. girodi increased with increasing availability of Brachionus in the medium. At any given prey density, A. girodi fed B. calyciflorus showed consistently better growth than when fed B. havanaensis. The maximum population densities of A. girodi varied from 0.28 to 1.8 ind. ml^–1 depending on the prey species and the density. The rate of population increase observed in population growth studies varied from 0.17 to 0.43 day^–1 when fed B. calyciflorus and 0.09 to 0.27 day^–1 when fed B. havanaensis. Male population of A. girodi was closely related to female density. The lowest average lifespan was observed for A. girodi when fed B. havanaensis at 1 ind. ml^–1, while the converse was the case when fed B. calyciflorus at comparable prey concentration. Net reproductive rates varied from 16 to 26 offspring female^–1 lifespan^–1 depending on the prey species and concentration. Generation time of A. girodi decreased with increasing food concentrations for both the prey species. The rates of population increase obtained from life table demography were lower for A. girodi when fed B. havanaensis than when fed B. calyciflorus.     

Optimizing performance of semi‐continuous cell culture in an ambr15™ microbioreactor using dynamic flux balance modeling

The ambr bioreactors are single‐use microbioreactors for cell line development and process optimization. With operating conditions for large‐scale biopharmaceutical production properly scaled down, microbioreactors such as the ambr15? can potentially be used to predict the effect of process changes such as modified media or different cell lines. While there have been some recent studies evaluating the ambr15? technology as a scale‐down model for fed‐batch operations, little has been reported for semi‐continuous or continuous operation. Gassing rates and dilution rates in the ambr15? were varied in this study to attempt to replicate performance of a perfusion process at the 5 L scale. At both scales, changes to metabolite production and consumption, and cell growth rate and therapeutic protein production were measured. Conditions were identified in the ambr15? bioreactor that produced metabolic shifts and specific metabolic and protein production rates that are characteristic of the corresponding 5 L perfusion process. A dynamic flux balance (DFB) model was employed to understand and predict the metabolic changes observed. The DFB model predicted trends observed experimentally, including lower specific glucose consumption and a switch from lactate production to consumption when dissolved CO₂ was maintained at higher levels in the broth. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:420–431, 2018     

Antileishmanial phenylpropanoids from Alpinia galanga (Linn.) Willd

Hexane, chloroform and ethyl acetate extracts (100 microg/ml) of Alpinia galanga rhizomes exhibited significant activity in vitro against promastigotes of L. donovani. Twelve compounds namely, methyleugenol (1), p-coumaryl diacetate (2), 1'-acetoxychavicol acetate (3), 1'-acetoxyeugenol acetate (4), trans-p-acetoxycinnamyl alcohol (5), trans-3,4-dimethoxycinnamyl alcohol (6), p-hydroxybenzaldehyde (7), p-hydroxycinnamaldehyde (8), trans-p-coumaryl alcohol (9), galangin (10), trans-p-coumaric acid (11) and galanganol B (12) were isolated from these extracts. Of these, compounds 2, 3, 4 and 5 were found most active in vitro against promastigotes of L. donovani with IC50 values of 39.3, 32.9, 18.9 and 79.9 microM respectively. This is the first report of antileishmanial activity of the extracts and isolated constituents of A. galanga.     

Antifungal Signature: Physicochemical and Structural In Silico Analysis of Some Antifungal Peptides

High throughput screening of antifungal peptide libraries have generated large number of information on peptide activities. However scientists are still struggling to explain the specific antifungal protein motifs resulting in their activities. So a thorough antifungal peptide optimization is required. To design and predict secondary structure of synthetic as well as natural antifungal peptide using in silico approaches, various parameters such as their sequences, physicochemical characterization, structures and functions should taken care to ensure a successful prediction. The primary interest of this study is to determine the properties that stabilize bonds of helices and coils of antifungal peptides along with their domains. Fifty different antifungal peptides have been analyzed in this study which were retrieved from uniprot and pdb databases and were characterized thoroughly using in silico tools. The present analysis showed that most of the antifungal peptides were hydrophobic in nature due to high content of nonpolar residues where as the functional domains were hydrophilic because of the presence of more polar residues. Many disulphide bonds were noticed in these peptides because of the presence of high cysteine residues which may be regarded as a positive factor for stability of linear helices and coils. Maximum number of random coils were observed in the domains of the studied peptides. The present study thus indicated that the peptidal domains of antifungal peptides contain structurally conserve signature though they are evolutionary diverse. Thus the present in silico models are able to guide the antifungal peptide design in a meaningful way.     

Rest-inserted loading rapidly amplifies the response of bone to small increases in strain and load cycles.

We hypothesized that a 10-s rest interval (at zero load) inserted between each load cycle would increase the osteogenic effects of mechanical loading near previously identified thresholds for strain magnitude and cycle numbers. We tested our hypothesis by subjecting the right tibiae of female C57BL/6J mice (16 wk, n = 70) to exogenous mechanical loading within a peri-threshold physiological range of strain magnitudes and load cycle numbers using a noninvasive murine tibia loading device. Bone responses to mechanical loading were determined via dynamic histomorphometry. More specifically, we contrasted bone formation induced by cyclic vs. rest-inserted loading (10-s rest at zero load inserted between each load cycle) by first varying peak strains (1,000, 1,250, or 1,600 micro epsilon) at fixed cycle numbers (50 cycles/day, 3 days/wk for 3 wk) and then varying cycle numbers (10, 50, or 250 cycles/day) at a fixed strain magnitude (1,250 micro epsilon). Within the range of strain magnitudes tested, the slope of periosteal bone formation rate (p.BFR/BS) with increasing strain magnitudes was significantly increased by rest-inserted compared with cyclical loading. Within the range of load cycles tested, the slope of p.BFR/BS with increasing load cycles of rest-inserted loading was also significantly increased by rest-inserted compared with cyclical loading. In sum, the data of this study indicate that inserting a 10-s rest interval between each load cycle amplifies bone's response to mechanical loading, even within a peri-threshold range of strain magnitudes and cycle numbers.     

Effects of thrombin,PAR-1 activating peptide and a PAR-1 antagonist on umbilical artery resistance in vitro

Background  

The non-thrombotic effects of thrombin in cardiovascular tissues, as mediated via the protease activated receptors (PARs), and particularly PAR-1, have been the focus of much recent research. The aims of this study were to evaluate the effects of thrombin, a specific PAR-1 activating peptide (PAR1-AP), and a PAR-1 antagonist on human umbilical artery tone in vitro.     

Effect of dietary fish on antioxidant parameters of normal and cholesterol stressed rats

Feeding fish (Sardinella longiceps) to normal rats increased lipid peroxidation and total and Se-dependent glutathione peroxidase (GSH-px) activity in erythrocytes and manganese dependent superoxide dismutase (Mn-SOD) activity in liver. Feeding fish to cholesterol stressed rats showed a significant increase in the activity of GSH-px and cholesterol feeding alone, resulted in a significant increase in the lipid peroxidation and liver Mn-SOD activity. The results suggest that the high polyunsaturated fatty acid content of S. longiceps, the fish abundantly available in the west coast of India, does not have any deleterious effect by way of free radical generation. The observed lipid peroxidation is not critical as is evident from the results of glutathione level and other scavenging enzymes.