Effect of culturing parameters on the vegetative growth of Haematococcus alpinus (strain lcr‐cc‐261f) and modeling of its growth kinetics

The present study investigated the effect of different culture conditions on the vegetative growth of a new species, Haematococcus alpinus (strain LCR‐CC‐261f) using airlift photobioreactors. The influence of culture medium, aeration rates, CO₂ concentration in air‐gas mixture, temperature, light intensities, and wavelengths were investigated to achieve sustainable high cell density cultures. Growth parameters were determined by fitting the data to a form of the logistic equation that included a lag phase. The shear‐sensitive vegetative cells favored lower aeration rates in the photobioreactors. MLA medium increased to 40 mM nitrate produced high density cultures. Temperatures between 12°C and 18°C, 3% (v/v) CO₂ concentration and a narrow photon flux density ranging between 37 and 48 μmol photons · m^?2 · s^?1 were best suited for growth. The wavelength of the light source also impacted growth and a high cell density of 9.6 × 10⁵ cells · mL^?1 was achieved using a mixture of red and blue compared to warm white, red, or blue LEDs.     

Reactive oxygen species function as second messenger during ischemic preconditioning of heart

The mechanisms involved in the hypolipidemic effects of fish oil have not been clearly established. This study shows that supplementation of 10% menhaden oil to the chick diet for 7 days produced a significant hypocholesterolemia and hypotriglyceridemia. Fatty acid composition of chick plasma drastically changed by the same dietary manipulation. Percentages of 20:5 and 22:6 n-3 fatty acids strongly increased, while percentages of 20:4 n-6, 18:2 n-6, and 18:1 n-9 significantly decreased. Changes observed in the relative percentages were parallel to those obtained in the amount of each fatty acid. Ratio of n-3/n-6 clearly decreased in plasma by fish oil feeding. Total cholesterol and triacylglycerol contents decreased in high density lipoprotein (HDL) but did not change in low density lipoprotein (LDL). All chemical constituents of very low density lipoprotein (VLDL) significantly decreased after the first week of menhaden oil supplementation to the diet. Similar modifications in fatty acid composition of the three lipoprotein fractions were also found. Our results suggest that the hypocholesterolemic effects of fish oil may be mediated by the depletion in VLDL synthesis and secretion into the chick plasma. On the other hand, the strong decrease found in the arachidonic acid (AA) content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.     

Pharmacological preconditioning with resveratrol: an insight with iNOS knockout mice

Resveratrol, a natural antioxidant and polyphenol found in grapes and wine, has been found to pharmacologically precondition the heart through the upregulation of nitric oxide (NO). To gain further insight of the role of NO in resveratrol preconditioning, mouse hearts devoid of any copies of inhibitory NO synthase (iNOS) (iNOS knockout) and corresponding wild-type hearts were perfused with 10 microM resveratrol for 15 min followed by 25 min of ischemia and 2 h of reperfusion. Control experiments were performed with wild-type and iNOS knockout hearts that were not treated with resveratrol. Resveratrol-treated wild-type mouse hearts displayed significant improvement in postischemic ventricular functional recovery compared with those of nontreated hearts. Both resveratrol-treated and nontreated iNOS knockout mouse hearts resulted in relatively poor recovery in ventricular function compared with wild-type resveratrol-treated hearts. Myocardial infarct size was lower in the resveratrol-treated wild-type mouse hearts compared with other group of hearts. In concert, a number of apoptotic cardiomyocytes was lower in the wild-type mouse hearts treated with resveratrol. Cardioprotective effects of resveratrol was abolished when the wild-type mouse hearts were simultaneously perfused with aminoguanidine, an iNOS inhibitor. Resveratrol induced the expression of iNOS in the wild-type mouse hearts, but not in the iNOS knockout hearts, after only 30 min of reperfusion. Expression of iNOS remained high even after 2 h of reperfusion. Resveratrol-treated wild-type mouse hearts were subjected to a lower amount of oxidative stress as evidenced by reduced amount of malonaldehyde content in these hearts compared with iNOS knockout and untreated hearts. The results of this study demonstrated that resveratrol was unable to precondition iNOS knockout mouse hearts, whereas it could successfully precondition the wild-type mouse hearts, indicating an essential role of iNOS in resveratrol preconditioning of the heart.     

Pharmacological preconditioning with resveratrol: role of nitric oxide

Resveratrol (trans-3,4',5-trihydroxystilbene), a recently described grape-derived polyphenolic antioxidant, has been found to protect the heart from ischemic-reperfusion injury. The present study sought to determine the mechanism of cardioprotection by investigating the ability of resveratrol to precondition the heart. Isolated perfused rat hearts were randomly divided into six groups: group I was perfused for 15 min with Kreb-Henseleit buffer (KHB) only; group II was perfused with 10 microM resveratrol; group III was perfused with 10 microM resveratrol plus 100 microM N(G)-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide (NO) synthase (NOS) inhibitor; group IV was perfused with 10 microM resveratrol plus 100 microM aminoguanidine (AG), an inducible NOS (iNOS) blocker; and groups V and VI consisted of hearts perfused with L-NAME and AG, respectively. The perfusion was then switched to working mode, and all hearts were made globally ischemic for 30 min followed by 2 h of reperfusion. Preconditioning of the hearts with resveratrol provided cardioprotection as evidenced by improved postischemic ventricular functional recovery (developed pressure and aortic flow) and reduced myocardial infarct size and cardiomyocyte apoptosis. Resveratrol-mediated cardioprotection was completely abolished by both L-NAME and AG. In a separate study, hearts were examined for iNOS mRNA induction. Resveratrol caused an induction of the expression of iNOS mRNA beginning at 30 min after reperfusion, increasing steadily up to 60 min of reperfusion, and then decreasing progressively up to 2 h after reperfusion. Preperfusion of the hearts with AG almost completely blocked the induction of iNOS. The results of our study demonstrate that resveratrol can pharmacologically precondition the heart in a NO-dependent manner.     

Synthesis of cellulose adipate derivatives

Cellulose esters containing adipates and other ester groups are synthesized by the reaction of commercially available cellulose esters in solution with the benzyl monoester of adipoyl chloride. The products, cellulose adipate esters in which the distal end of the adipate moiety is a benzyl ester, were easily converted to cellulose adipate derivatives by Pd-catalyzed hydrogenation. These cellulose adipate derivatives are promising biopolymers for drug delivery and other applications in which water-dispersion or swelling are desired.     

Functional alteration of a dimeric insecticidal lectin to a monomeric antifungal protein correlated to its oligomeric status

Background

Allium sativum leaf agglutinin (ASAL) is a 25-kDa homodimeric, insecticidal, mannose binding lectin whose subunits are assembled by the C-terminal exchange process. An attempt was made to convert dimeric ASAL into a monomeric form to correlate the relevance of quaternary association of subunits and their functional specificity. Using SWISS-MODEL program a stable monomer was designed by altering five amino acid residues near the C-terminus of ASAL.

Methodology/Principal Findings

By introduction of 5 site-specific mutations (-DNSNN-), a β turn was incorporated between the 11^th and 12^th β strands of subunits of ASAL, resulting in a stable monomeric mutant ASAL (mASAL). mASAL was cloned and subsequently purified from a pMAL-c2X system. CD spectroscopic analysis confirmed the conservation of secondary structure in mASAL. Mannose binding assay confirmed that molecular mannose binds efficiently to both mASAL and ASAL. In contrast to ASAL, the hemagglutination activity of purified mASAL against rabbit erythrocytes was lost. An artificial diet bioassay of Lipaphis erysimi with mASAL displayed an insignificant level of insecticidal activity compared to ASAL. Fascinatingly, mASAL exhibited strong antifungal activity against the pathogenic fungi Fusarium oxysporum, Rhizoctonia solani and Alternaria brassicicola in a disc diffusion assay. A propidium iodide uptake assay suggested that the inhibitory activity of mASAL might be associated with the alteration of the membrane permeability of the fungus. Furthermore, a ligand blot assay of the membrane subproteome of R. solani with mASAL detected a glycoprotein receptor having interaction with mASAL.

Conclusions/Significance

Conversion of ASAL into a stable monomer resulted in antifungal activity. From an evolutionary aspect, these data implied that variable quaternary organization of lectins might be the outcome of defense-related adaptations to diverse situations in plants. Incorporation of mASAL into agronomically-important crops could be an alternative method to protect them from dramatic yield losses from pathogenic fungi in an effective manner.