Microvascular transport model predicts oxygenation changes in the infarcted heart after treatment

Chronic heart failure is most commonly due to ischemic cardiomyopathy after a previous myocardial infarction (MI). Rebuilding lost myocardium to prevent heart failure mandates a neovasculature able to nourish new cardiomyocytes. Previously we have used a series of novel techniques to directly measure the ability of the scar neovasculature to deliver and exchange oxygen at 1-4 wk after MI in rats following left coronary artery ligation. In this study, we have developed a morphologically realistic mathematical model of oxygen transport in cardiac tissue to help in deciding what angiogenic strategies should be used to rebuild the vasculature. The model utilizes microvascular morphology of cardiac tissue based on available morphometric images and is used to simulate experimentally measured oxygen levels after MI. Model simulations of relative oxygenation match experimental measurements closely and can be used to simulate distributions of oxygen concentration in normal and infarcted rat hearts. Our findings indicate that both vascular density and vascular spatial distribution play important roles in cardiac tissue oxygenation after MI. Furthermore, the model can simulate relative changes in tissue oxygen levels in infarcted tissue treated with proangiogenic compounds such as losartan. From the minimum oxygen concentration myocytes need to maintain their normal function, we estimate that 2 wk after MI 29% of the myocardium is severely hypoxic and that the vascular density of the infarcted tissue should reach 75% of normal tissue to ensure that no areas of the myocardium are critically hypoxic.     

Drosophila Omi, a mitochondrial-localized IAP antagonist and proapoptotic serine protease

Although essential in mammals, in flies the importance of mitochondrial outer membrane permeabilization for apoptosis remains highly controversial. Herein, we demonstrate that Drosophila Omi (dOmi), a fly homologue of the serine protease Omi/HtrA2, is a developmentally regulated mitochondrial intermembrane space protein that undergoes processive cleavage, in situ, to generate two distinct inhibitor of apoptosis (IAP) binding motifs. Depending upon the proapoptotic stimulus, mature dOmi is then differentially released into the cytosol, where it binds selectively to the baculovirus IAP repeat 2 (BIR2) domain in Drosophila IAP1 (DIAP1) and displaces the initiator caspase DRONC. This interaction alone, however, is insufficient to promote apoptosis, as dOmi fails to displace the effector caspase DrICE from the BIR1 domain in DIAP1. Rather, dOmi alleviates DIAP1 inhibition of all caspases by proteolytically degrading DIAP1 and induces apoptosis both in cultured cells and in the developing fly eye. In summary, we demonstrate for the first time in flies that mitochondrial permeabilization not only occurs during apoptosis but also results in the release of a bona fide proapoptotic protein.     

Optimization of triaryl bis-sulfones as cannabinoid-2 receptor ligands

Structure-activity relationship on our recently reported triaryl bis-sulfone class of cannabinoid-2 (CB2) receptor selective inverse agonists was explored. Modifications to the methane sulfonamide, substitutions to B and C phenyl rings, and replacements of the C-ring were investigated. A compound with excellent CB2 activity, selectivity for CB2 over CB1, and in vivo plasma levels was identified.     

Alpha-galactosidase production by Aspergillus oryzae in solid-state fermentation

Comparisons were made for alpha-galactosidase production using red gram plant waste (RGPW) with wheat bran (WB) and other locally available substrates using the fungus Aspergillus oryzae under solid-state fermentation (SSF). RGPW proved to be potential substrate for alpha-galactosidase production as it gave higher enzyme titers (3.4 U/g) compared to WB (2.7 U/g) and other substrates tested. Mixing WB with RGPW (1:1, w/w) resulted enhanced alpha-galactosidase yield. The volume of moistening agent in the ratio of 1:2 (w/v), pH 5.5 and 1 ml (1 x 10(6) spores) of inoculum volume and four days incubation were optimum for alpha-galactosidase production. Increase in substrate concentration (RGPW+WB) did not decrease enzyme yield in trays.     

Differential effects of lysophosphatidylcholine on the adsorption of phospholipids to an air/water interface

To determine how the hydrophobic surfactant proteins promote insertion of the surfactant lipids into an air/water interface, we measured the effect of lysophosphatidylcholine (LPC) on adsorption. Existing models contend that the proteins function either by disordering the lipids or by stabilizing a negatively curved structure located between the adsorbing vesicle and the interface. Because LPC produces greater disorder but positive curvature, the models predict opposite effects. With vesicles containing either dioleoyl phosphatidylcholine (DOPC) or the neutral and phospholipids isolated from calf surfactant, LPC increased the initial rate at which surface tension fell. The final surface tension, however, remained well above the value of approximately 25 mN/m expected for a saturated surface. With two preparations, dioleoyl phosphatidylethanolamine and gramicidin A-DOPC, which form the negatively curved hexagonal-II (H(II)) phase and adsorb rapidly, LPC instead had little effect on initial adsorption but delayed the fall of surface tension below approximately 30 mN/m. LPC produced a similar inhibition of the late adsorption for extracted calf surfactant. Unlike dioleoyl phosphatidylethanolamine and gramicidin A-DOPC, small-angle x-ray scattering and (31)P-nuclear magnetic resonance for extracted calf surfactant detected no evidence for the H(II) phase. Our results indicate that although LPC can promote the initial adsorption of vesicles containing only lamellar lipids, it inhibits the facilitation by the hydrophobic proteins of late adsorption. Our findings support a model in which the surfactant proteins accelerate adsorption by producing a focal tendency to stabilize a negatively curved kinetic intermediate without a general shift to the H(II) phase.     

Degradation of raffinose oligosaccharides in soymilk by immobilized alpha-galactosidase of Aspergillus oryzae

Alpha-galactosidase was immobilized in a mixture of k-carrageenan and locust bean gum. The properties of the free and immobilized enzyme were then determined. The optimum pH for both the soluble and immobilized enzyme was 4.8. The optimum temperature for the soluble enzymes was 50 degrees C, whereas that for the immobilized enzyme was 55 degrees C. The immobilized enzyme was used in batch, repeated batch, and continuous modes to degrade the raffinose-family sugars present in soymilk. Two hours of incubation with the free and immobilized alpha-galactosidases resulted in an 80% and 68% reduction in the raffinose oligosaccharides in the soymilk, respectively. In the repeated batch, a 73% reduction was obtained in the fourth cycle. A fluidized bed reactor was also designed to treat soymilk continuously and the performance of the immobilized alpha-galactosidase tested at different flow rates, resulting in a 90% reduction of raffinose-family oligosaccharides in the soymilk at a flow rate 40 ml/h. Therefore, the present study demonstrated that immobilized alpha-galactosidase in a continuous mode is efficient for reducing the oligosaccharides present in soymilk, which may be of considerable interest for industrial application.     

A risk-based bioanalytical strategy for the assessment of antibody immune responses against biological drugs

Bioanalytical assessments of anti-drug antibodies (ADAs) provide an understanding of the immunogenicity of biological drug molecules. The potential to induce ADAs after treatment with biologics is a safety issue that has become an important consideration in the development of biologics and a critical aspect of regulatory filings. US and European regulatory agencies are recommending that sponsors study immunogenicity using a risk-based approach, encouraging sponsors to formulate and implement their own risk management plans and to conduct discussions with the agencies when necessary. It follows from this that the greater the safety risks of ADAs, the more diligently one should clarify the immunogenicity of the product. Here we propose a general strategy to broadly assign immunogenicity risk levels to biological drug products, and present risk level-based 'fit-for-purpose' bioanalytical schemes for the investigations of treatment-related ADAs in clinical and nonclinical studies.     

Cryopreservation and genetic stability assessment of regenerants of the critically endangered medicinal plant Dioscorea deltoidea Wall. ex Griseb. for cryobanking of germplasm

In Vitro Cellular & Developmental Biology - Plant - Dioscorea deltoidea Wall. ex Griseb. is a critically endangered, commercially important crop of high medicinal value. Several accessions of...     

Insights on genomic diversity of Vibrio spp. through Pan-genome analysis

Purpose

The aquaculture sector is a major contributor to the economic and nutritional security for a number of countries. India’s total seafood exports for the year 2017–2018 accounted for US$ Million 7082. One of the major setbacks in this sector is the frequent outbreaks of diseases often due to bacterial pathogens. Vibriosis is one of the major diseases caused by bacteria of Vibrio spp., causing significant economic loss to the aquaculture sector. The objective of this study was to understand the genetic composition of Vibrio spp.

Methods

Thirty-five complete genomes were downloaded from GenBank comprising seven vibrio species, namely, Vibrio alginolyticus, V. anguillarum, V. campbellii, V. harveyi, V. furnissii, V. parahaemolyticus, and V. vulnificus. Pan-genome analysis was carried out with coding sequences (CDS) generated from all the Vibrio genomes. In addition, genomes were mined for genes coding for toxin-antitoxin systems, antibiotic resistance, genomic islands, and virulence factors.

Results

Results revealed an open pan-genome comprising of 2004 core, 8249 accessory, and 6780 unique genes. Downstream analysis of genomes and the identified unique genes resulted in 312 antibiotic resistance genes, 430 genes coding for toxin and antitoxin systems along with 4802, and 4825 putative virulent genes from genomic island regions and unique gene sets, respectively.

Conclusion

Pan-genome and other downstream analytical procedures followed in this study have the potential to predict strain-specific genes and their association with habitat and pathogenicity.