Lemmuel L. Tayo

Bio: Lemmuel L. Tayo is an academic researcher from Mapúa Institute of Technology. The author has contributed to research in topics: Medicine & Membrane. The author has an hindex of 16, co-authored 57 publications receiving 671 citations. Previous affiliations of Lemmuel L. Tayo include University of the Philippines Diliman & University of the Philippines.

Proteomic Analysis Provides Insights on Venom Processing in Conus textile

Abstract: Conus species of marine snails deliver a potent collection of toxins from the venom duct via a long proboscis attached to a harpoon tooth. Conotoxins are known to possess powerful neurological effects and some have been developed for therapeutic uses. Using mass-spectrometry based proteomics, qualitative and quantitative differences in conotoxin components were found in the proximal, central and distal sections of the Conus textile venom duct suggesting specialization of duct sections for biosynthesis of particular conotoxins. Reversed phase HPLC followed by Orbitrap mass spectrometry and data analysis using SEQUEST and ProLuCID identified 31 conotoxin sequences and 25 post-translational modification (PTM) variants with King-Kong 2 peptide being the most abundant. Several previously unreported variants of known conopeptides were found and this is the first time that HyVal is reported for a disulfide rich Conus peptide. Differential expression along the venom duct, production of PTM variants, alternative p...

Rapid microfluidic paper-based platform for low concentration formaldehyde detection

Abstract: An integrated platform consisting of a microfluidic paper-based analytical device (μPAD) and a portable detection system is proposed for low concentration formaldehyde (CH 2 O) detection. In the proposed approach, the reaction zone of the μPAD is coated with ammonium acetate (AA) and acetoacetanilide (AAA) indicator and is dried at 40 °C for 30 min. The formaldehyde sample is then dripped on the reaction zone and the μPAD is transferred to a hot plate in the portable detection system. A Hantzsch reaction is induced by heating the μPAD at 30 °C for 10 min. The resulting fluorescent formaldehyde-Acetoacetanilide complex (dihydropyridine derivative) is observed by a CMOS camera and the color image is transferred to a smartphone by means of a connector. Finally, the CH 2 O concentration is derived using self-written RGB color analysis mobile software implemented on the phone. The experimental results obtained using control samples with known CH 2 O concentrations in the range of 0.2–2.5 ppm show that the B (blue) fluorescence intensity (Y) and formaldehyde concentration (X) are related as Y = 29.455 X + 117.64. Moreover, the correlation coefficient is equal to R 2 = 0.9937. The real-world applicability of the proposed detection platform is demonstrated by measuring the CH 2 O concentration in twelve commercial food samples. It is shown that the concentration measurements obtained using the proposed system deviate by no more than 6.2% from those obtained using a conventional spectrophotometric technique. Overall, the results presented in this study show that the proposed integrated microfluidic paper-based system provides a compact and reliable tool for low concentration CH 2 O measurement purposes.

Stimuli-responsive nanocarriers for intracellular delivery

Abstract: The emergence of different nanoparticles (NPs) has made a significant revolution in the field of medicine. Different NPs in the form of metallic NPs, dendrimers, polymeric NPs, carbon quantum dots and liposomes have been functionalized and used as platforms for intracellular delivery of biomolecules, drugs, imaging agents and nucleic acids. These NPs are designed to improve the pharmacokinetic properties of the drug, improve their bioavailability and successfully surpass physiological or pathological obstacles in the biological system so that therapeutic efficacy is achieved. In this review I present some of the current approaches used in intracellular delivery systems, with a focus on various stimuli-responsive nanocarriers, including cell-penetrating peptides, to highlight their various biomedical applications.

Photodegradation of Reactive Black 5 in a ZnO/UV slurry membrane reactor

Abstract: This paper describes the photodegradation of commercial azo dye, Reactive Black 5 (RB5) in a slurry membrane reactor operated under batch and continuous modes. Initially, the photocatalytic activity of TiO2 and ZnO for decolorization of RB5 was evaluated and the best results were achieved with ZnO. Based on these results, the effect of operating parameters including catalyst load (0.5–1.5 g/L), initial dye concentration (25–150 mg/L) and pH (3.0–11.0) on color removal was investigated in detail. The results showed that the decolorization of RB5 depended on reaction time and dye concentration. The color removal rate is faster in low initial dye concentration and it increased with increasing ZnO concentration upto 1.25 mg/L. At ZnO concentration beyond this level, reduction of color removal was observed. As a result of combined effects between dye photolysis and photoactivity of ZnO, the highest RB5 removal rate was found at pH 11 with a nearly 100% removal within 60 min. The photocatalytic decolorization of RB5 by ZnO/UV follows the pseudo-first-order kinetics. Reusability study and the continuous experiments indicated that ZnO catalyst has a potential for long-term use without losing its activity and the reactor can be easily extended to pilot scale applications.

Diagnosis and potential treatments for acute hepatopancreatic necrosis disease (AHPND): a review.

Abstract: Acute hepatopancreatic necrosis disease (AHPND) or formerly known as early mortality syndrome (EMS) is an emerging disease that has caused significant economic losses to the aquaculture industry. The primary causative agent of AHPND is Vibrio parahaemolyticus, a Gram-negative rod-shaped bacterium that has gained plasmids encoding the fatal binary toxins Pir A/Pir B that cause rapid death of the infected shrimp. In this review, the current research studies and information about AHPND in shrimps have been presented. Molecular diagnostic tools and potential treatments regarding AHPND were also included. This review also includes relevant findings which may serve as guidelines that can help for further investigation and studies on AHPND or other shrimp diseases.

A 20-year retrospective review of global aquaculture.

Abstract: The sustainability of aquaculture has been debated intensely since 2000, when a review on the net contribution of aquaculture to world fish supplies was published in Nature. This paper reviews the developments in global aquaculture from 1997 to 2017, incorporating all industry sub-sectors and highlighting the integration of aquaculture in the global food system. Inland aquaculture—especially in Asia—has contributed the most to global production volumes and food security. Major gains have also occurred in aquaculture feed efficiency and fish nutrition, lowering the fish-in–fish-out ratio for all fed species, although the dependence on marine ingredients persists and reliance on terrestrial ingredients has increased. The culture of both molluscs and seaweed is increasingly recognized for its ecosystem services; however, the quantification, valuation, and market development of these services remain rare. The potential for molluscs and seaweed to support global nutritional security is underexploited. Management of pathogens, parasites, and pests remains a sustainability challenge industry-wide, and the effects of climate change on aquaculture remain uncertain and difficult to validate. Pressure on the aquaculture industry to embrace comprehensive sustainability measures during this 20-year period have improved the governance, technology, siting, and management in many cases. The volume of global aquaculture production has tripled since 2000 with positive trends in environmental performance, but the sector faces mounting challenges including pathogen management, pollution, climate change, and increasing dependence on land-based resource systems.

Byonic: Advanced Peptide and Protein Identification Software

Abstract: Byonic is the name of a software package for peptide and protein identification by tandem mass spectrometry. This software, which has only recently become commercially available, facilitates a much wider range of search possibilities than previous search software such as SEQUEST and Mascot. Byonic allows the user to define an essentially unlimited number of variable modification types. Byonic also allows the user to set a separate limit on the number of occurrences of each modification type, so that a search may consider only one or two chance modifications such as oxidations and deamidations per peptide, yet allow three or four biological modifications such as phosphorylations, which tend to cluster together. Hence, Byonic can search for tens or even hundreds of modification types simultaneously without a prohibitively large combinatorial explosion. Byonic's Wildcard Search allows the user to search for unanticipated or even unknown modifications alongside known modifications. Finally, Byonic's Glycopeptide Search allows the user to identify glycopeptides without prior knowledge of glycan masses or glycosylation sites.

Evolution of separate predation- and defence-evoked venoms in carnivorous cone snails

Abstract: Venomous animals are thought to inject the same combination of toxins for both predation and defence, presumably exploiting conserved target pharmacology across prey and predators Remarkably, cone snails can rapidly switch between distinct venoms in response to predatory or defensive stimuli Here, we show that the defence-evoked venom of Conus geographus contains high levels of paralytic toxins that potently block neuromuscular receptors, consistent with its lethal effects on humans In contrast, C geographus predation-evoked venom contains prey-specific toxins mostly inactive at human targets Predation- and defence-evoked venoms originate from the distal and proximal regions of the venom duct, respectively, explaining how different stimuli can generate two distinct venoms A specialized defensive envenomation strategy is widely evolved across worm, mollusk and fish-hunting cone snails We propose that defensive toxins, originally evolved in ancestral worm-hunting cone snails to protect against cephalopod and fish predation, have been repurposed in predatory venoms to facilitate diversification to fish and mollusk diets

Disulfide Bond-Driven Oxidation- and Reduction-Responsive Prodrug Nanoassemblies for Cancer Therapy.

Abstract: Disulfide bonds have been widely used to develop reduction-responsive drug-delivery systems (DDS) for cancer therapy. We propose that disulfide bonds might be also used as an oxidation-responsive linkage just like thioether bonds, which can be oxidized to hydrophilic sulfoxide or sulphone in the presence of oxidation stimuli. To test our hypothesis, we design three novel paclitaxel-citronellol conjugates linked via different lengths of disulfide-bond-containing carbon chain. The prodrugs can self-assemble into uniform-size nanoparticles with impressively high drug loading (>55%). As expected, the disulfide-bond-bridged prodrug nanoparticles show redox dual-responsive drug release. More interestingly, the position of disulfide bonds in the carbon chain linkage has profound impacts on the redox dual responsiveness, thereby affecting the drug release, cytotoxicity, pharmacokinetics, biodistribution, and in vivo antitumor efficacy of prodrug nanoassemblies. The redox dual-responsive mechanism is elucidated, and how the position of disulfide bonds in the carbon chain affects the redox dual responsiveness and antitumor efficiency of prodrug nanoassemblies is also clarified. Our findings give new insight into the stimuli responsiveness of disulfide bonds and provide a good foundation for the development of novel redox dual-responsive DDS for cancer therapy.

Discovery, synthesis, and structure-activity relationships of conotoxins.

Abstract: Peptide therapeutics are acclaimed as a promising addition to the pharmaceutical arena, and they continue to attract interest due to their high potency, bioavailability, and fewer concerns with toxicity, drug to drug cross-reactions, and tissue accumulation. Around 700 species of marine snails of the genus Conus are distributed throughout tropical and subtropical waters. As different species preferentially hunt fish, worms, or molluscs they are categorized as piscivorous, vermivorous, or molluscivorous, respectively, although some cone snail species can feed on more than one prey type. These slow-moving creatures evolved into predators through incorporation of a specialized envenomation apparatus that enables them to quickly subdue their fast-moving prey. Conotoxins target a wide range of receptors and ion channels with unparalleled potency and selectivity. They have consequently become the subject of intense research in light of their immense diagnostic and therapeutic potential and are the focus of this review.