Purification and Characterization of Antioxidant Peptides from Oyster (Saccostrea cucullata) Hydrolysate and the Anticancer Activity of Hydrolysate on Human Colon Cancer Cell Lines

The focus of the study was to investigate antioxidant activity and characterize antioxidant peptides from oyster (Saccostrea cucullata) protein hydrolysate. The protease hydrolysate of oyster exhibited strong potential to donate hydrogen and was able to scavenge Hydrogen peroxide, Hydroxyl and DPPH radicals. Due to the high antioxidant potential, hydrolysate was purified in Sephadex G-25 gel filtration chromatography. The active peptide fraction was further purified by UPLC-MS. Totally seven antioxidant peptides were collected. Among seven peptides (SCAP 1–7), three peptides (SCAP 1, 3 and 7) had highest scavenging ability on DPPH radicals. The amino acid sequence and molecular mass of purified antioxidant peptides (SCAP1, SCAP3 and SCAP7) were determined by Q-TOF ESI mass spectroscopy and structures of the peptides were Leu-Ala-Asn-Ala-Lys (MW = 515.29 Da), Pro-Ser-Leu-Val-Gly-Arg-Pro–Pro-Val-Gly-Lys-Leu-Thr-Leu (MW = 1,432.89 Da) and Val-Lys-Val-Leu-Leu-Glu-His-Pro-Val-Leu (MW = 1,145.75 Da), respectively. The oyster hydrolysate was tested for cell cytotoxicity on Vero (kidney epithelial cells of the African Green Monkey) and HT-29 (human colon carcinoma) cell lines. It was found that the hydrolysate did not show any cytotoxic effect for Vero cell lines and exerted a significant cytotoxic effect on HT-29 cell lines. We thus conclude that the anticancer and antioxidative hydrolysate from oyster (S. cucullata) may be useful ingredients in food and nutraceutical applications.     

Structural Insights into the Evolution of a Sexy Protein: Novel Topology and Restricted Backbone Flexibility in a Hypervariable Pheromone from the Red-Legged Salamander,Plethodon shermani

In response to pervasive sexual selection, protein sex pheromones often display rapid mutation and accelerated evolution of corresponding gene sequences. For proteins, the general dogma is that structure is maintained even as sequence or function may rapidly change. This phenomenon is well exemplified by the three-finger protein (TFP) superfamily: a diverse class of vertebrate proteins co-opted for many biological functions – such as components of snake venoms, regulators of the complement system, and coordinators of amphibian limb regeneration. All of the >200 structurally characterized TFPs adopt the namesake “three-finger” topology. In male red-legged salamanders, the TFP pheromone Plethodontid Modulating Factor (PMF) is a hypervariable protein such that, through extensive gene duplication and pervasive sexual selection, individual male salamanders express more than 30 unique isoforms. However, it remained unclear how this accelerated evolution affected the protein structure of PMF. Using LC/MS-MS and multidimensional NMR, we report the 3D structure of the most abundant PMF isoform, PMF-G. The high resolution structural ensemble revealed a highly modified TFP structure, including a unique disulfide bonding pattern and loss of secondary structure, that define a novel protein topology with greater backbone flexibility in the third peptide finger. Sequence comparison, models of molecular evolution, and homology modeling together support that this flexible third finger is the most rapidly evolving segment of PMF. Combined with PMF sequence hypervariability, this structural flexibility may enhance the plasticity of PMF as a chemical signal by permitting potentially thousands of structural conformers. We propose that the flexible third finger plays a critical role in PMF:receptor interactions. As female receptors co-evolve, this flexibility may allow PMF to still bind its receptor(s) without the immediate need for complementary mutations. Consequently, this unique adaptation may establish new paradigms for how receptor:ligand pairs co-evolve, in particular with respect to sexual conflict.     

Monopolin Subunit Csm1 Associates with MIND Complex to Establish Monopolar Attachment of Sister Kinetochores at Meiosis I

Sexually reproducing organisms halve their cellular ploidy during gametogenesis by undergoing a specialized form of cell division known as meiosis. During meiosis, a single round of DNA replication is followed by two rounds of nuclear divisions (referred to as meiosis I and II). While sister kinetochores bind to microtubules emanating from opposite spindle poles during mitosis, they bind to microtubules originating from the same spindle pole during meiosis I. This phenomenon is referred to as mono-orientation and is essential for setting up the reductional mode of chromosome segregation during meiosis I. In budding yeast, mono-orientation depends on a four component protein complex referred to as monopolin which consists of two nucleolar proteins Csm1 and Lrs4, meiosis-specific protein Mam1 of unknown function and casein kinase Hrr25. Monopolin complex binds to kinetochores during meiosis I and prevents bipolar attachments. Although monopolin associates with kinetochores during meiosis I, its binding site(s) on the kinetochore is not known and its mechanism of action has not been established. By carrying out an imaging-based screen we have found that the MIND complex, a component of the central kinetochore, is required for monopolin association with kinetochores during meiosis. Furthermore, we demonstrate that interaction of monopolin subunit Csm1 with the N-terminal domain of MIND complex subunit Dsn1, is essential for both the association of monopolin with kinetochores and for monopolar attachment of sister kinetochores during meiosis I. As such this provides the first functional evidence for a monopolin-binding site at the kinetochore.     

Diversity and analysis of sequences encoded by arcelin genes from Indian wild pulses resistant to bruchids

Wild pulse accessions are considered a vital source of genes for insect resistance for crop improvement programmes. Wild pulses resistant to infestation towards the bruchid insect pest, Callosobruchus maculatus from South India were chosen to screen the existence of potent insecticidal protein, arcelin from APA locus (Arcelin/Phytohemagglutinin/α-Amylase inhibitor) to ascertain their nature and functional diversity without any specific indication for insect resistant factors. The DNA sequence coding for arcelin from various species of wild pulses were amplified, sequenced and deduced to their protein sequences. These protein sequences were examined physico-chemically using several bioinformatics tools and docked with various sugars to resolve the nature of arcelin molecules. Results indicated the presence of significant differences in the properties of arcelin molecules from various species of Indian wild pulses with their amino acid sequences, several physico-chemical properties and binding ability with sugars. The differences observed on these arcelin molecules from diverse wild pulses are predicted to provide a prospective insect pest control factors.     

Cholinesterase inhibitory activity of highly functionalized fluorinated spiropyrrolidine heterocyclic hybrids

Two series of dimethoxyindanone imbedded novel fluorinated spiropyrrolidine heterocyclic hybrids were synthesized employing two different less explored azomethine ylides and were measured for their efficiency as inhibitors for Alzheimer’s disease. Among the spiropyrrolidine heterocyclic hybrids, the indole based fluorinated compound with a methoxy substituent at the meta- position of the aryl ring exhibited the utmost potent AChE and BChE inhibitory activities with an IC₅₀ of 1.97 ± 0.19 µM and 7.08 ± 0.20 µM respectively. The plausible mechanism of inhibition on ChE receptors was unveiled via molecular docking studies.     

Antimicrobial Substance Produced by Pseudomonas aeruginosa Isolated from Slaughterhouse Sediment: Physicochemical Characterization,Purification, and Identification

International Journal of Peptide Research and Therapeutics - This study aimed to produce the novel bacteriocin from Pseudomonas aeruginosa 43. The bacteriocin was purified through 80% ammonium...     

Recovery and utilization of proteinous wastes of leather making: a review

Hides and skins, by-product of the meat industry is converted into a value added product namely leather by the tanners. Tanning essentially is the process of converting raw hides and skins into imputrescible substance. The tanning process has number of steps and generates significant quantities of by products and wastes. These solid and liquid wastes pose major environmental problem if not managed effectively. Large–scale production systems are adopted for leather processing in clusters and therefore, the industry receives focus of environmentalists and society. Consequently tremendous pressure is exerted by various pollution regulatory bodies. The hides and skins, after trimming, removal of flesh and fat, are treated with chemicals, which cross-link the collagen fibers to form a stable, durable material. The chemicals used may be derived from traditional vegetable products, or inorganic metal salts. During leather processing number of size reduction, leveling and purification operations are carried out which results in generation of untanned and tanned proteinous waste materials. In this paper, various recovery processes and utilization methodologies of proteinous solid wastes, emanating from leather processing operations prior to tanning is reviewed.     

HIV-1 Gag Cytotoxic T Lymphocyte Epitopes Vary in Presentation Kinetics Relative to HLA Class I Downregulation

Although CD8⁺ cytotoxic T lymphocytes (CTLs) are protective in HIV-1 infection, the factors determining their antiviral efficiency are poorly defined. It is proposed that Gag targeting is superior because of very early Gag epitope presentation, allowing early killing of infected cells before Nef-mediated downregulation of human leukocyte antigen class I (HLA-I). To study Gag epitope presentation kinetics, three epitopes (SL9_77-85, KF11_162-172, and TW10_240-249) were genetically translocated from their endogenous location in the Rev-dependent (late) gag gene into the Rev-independent (early) nef gene with concomitant mutation of the corresponding endogenous epitopes to nonrecognized sequences. These viruses were compared to the index virus for CTL-mediated suppression of replication and the susceptibility of this antiviral activity to Nef-mediated HLA-I downregulation. SL9-specific CTLs gained activity after SL9 translocation to Nef, going from Nef sensitive to Nef insensitive, indicating that translocation accelerated infected cell recognition from after to before HLA-I downregulation. KF11-specific CTL antiviral activity was unchanged and insensitive to HLA-I downregulation before and after KF11 translocation, suggesting that already rapid recognition of infected cells was not accelerated. However, TW10-specific CTLs that were insensitive to Nef at the baseline became sensitive with reduced antiviral activity after translocation, indicating that translocation retarded epitope expression. Cytosolic peptide processing assays suggested that TW10 was inefficiently generated after translocation to Nef, compared to SL9 and KF11. As a whole, these data demonstrate that epitope presentation kinetics play an important role in CTL antiviral efficiency, that Gag epitopes are not uniformly presented early, and that the epitope context can play a major role in presentation kinetics.