Silvana Laura Giudicessi

National Scientific and Technical Research Council | conicet · Instituto de Nanobiotecnologia UBA-CONICET

Background Antimicrobial peptides (AMPs) are positive-charged small molecules of less than 50 amino acids, with antibacterial and antifungal properties. The main mechanism of action against pathogens is the cell membrane disruption. Particularly in plants, most of the AMPs are cysteine-rich peptides (CRPs), which allow the formation of numerous dis...

From the initial steps of early drug discovery, the traditional techniques, like docking, QSAR, or molecular dynamics, have been used for decades identifying targets, ranking molecule candidates and optimizing the lead compounds chemically to decrease toxicity and improve drug absorption, distribution, metabolism, and excretion (ADME) properties. N...

In 2019, severe acute respiratory syndrome caused by CoV-2 virus became a pandemic worldwide, being the fast spread of the disease due to the movement of infected people from one country to another, from one continent to another, or within the same country. Associated comorbidities are important factors that predispose to any fungal coinfections. B...

The interest in therapeutic monoclonal antibodies (mAbs) has significantly grown in the pharmaceutical industry, exceeding 100 FDA mAbs approved. Although the upstream processing of their industrial production has been significantly improved in the last years, the downstream processing still depends on immobilized protein A affinity chromatography....

Biodeterioration is related to several biological systems and metabolic activities of fungi and bacteria. Fungal contamination is determined by the availability of water and temperature. Aspergillus is a fungus with great enzymatic capacity and with a high biodeterioration power. For this reason, it represents a threat to the conservation of cultur...

Peptide ligands are widely used in protein purification by affinity chromatography. Here, we applied a fully automated two-stage library screening method that avoids false positive peptidyl-bead selection and applied it to tetanus toxoid purification. The first library screening was performed using only sulforhodamine (a fluorescent dye), and fluor...

In recent years, the incidence and severity of fungal diseases has increased, particularly in populations with a broad list of immunocompromised conditions. Moreover, the emergence of azole resistance is arising. For these reasons and the small number of available antifungal agents, searching for new and effective compounds with antifungal activity...

In this chapter, a protocol to design affinity chromatography matrices with short peptide ligands immobilized for protein purification is described. The first step consists of the synthesis of a combinatorial peptide library on the hydroxymethylbenzoyl (HMBA)-ChemMatrix resin by the divide–couple–recombine (DCR) method using the Fmoc chemistry. Nex...

After the Industrial Revolution, humanity began to exploit non-renewable resources, such as oil and gas, with dangerous consequences for the environment. In the last 50 years, different strategies have been implemented to reduce the environmental impact produced by the chemical and pharmaceutical industries. Biotechnology offers different perspecti...

Scorpion and spider envenomation is treated with the appropriate antivenoms, prepared as described by Césaire Auguste Phisalix and Albert Calmette in 1894. Such treatment requires the acquisition and manipulation of arachnid venoms, both very complicated procedures. Most of the toxins in the venoms of spiders and scorpions are extremely stable cyst...

It is the 20th World Congress of the International Society on Toxinology abstract

The venom of Crotalus durissus terrificus (Cdt) is a source of a wide variety of toxins, some of them with interesting pharmacological applications. Of these toxins, the phospholipase A2 (PLA2) subunit of crotoxin (Ctx) has been studied for its potential as an antiviral and antibacterial agent. Peptides have proven useful ligands for the purificati...

Antimicrobial peptides (AMPs), also known as host defense peptides, are small and mostly polycationic molecules that form part of the innate immune response. There are currently more than 3000 experimentally reported AMPs. Particularly in frogs, the temporin family has been discovered as potential AMPs. The aim of this work is to review the latest...

Bevacizumab is a monoclonal antibody, produced in CHO cells, used for the treatment of many human cancers. It is an anti-vascular endothelial growth factor (antsi-VEGF) that blocks the growth of tumor blood vessels. Nowadays its purification is achieved by affinity chromatography (AC) using protein A which is a very expensive ligand. On the other h...

ambos autores colaboraron de forma equivalente. Se ha propuesto usar fosfolipasa A2 (PLA2) presente en el veneno de la serpiente Crotalus durissus terrificus (Cdt) como posible agente antiviral. La PLA2 se encuentra acomplejada con la crotapotina (Ctp), una chaperona que la acompaña hasta el sitio de acción. Dicho complejo, llamado crotoxina, repre...

INTRODUCCIÓN La fosfolipasa A2 (PLA 2), principal componente del veneno de la serpiente Crotalus durissus terrificus (Cdt), se encuentra formando un complejo con la crotapotina (Ctp). Esta última actúa como chaperona acompañándola hasta el sitio de acción. Se ha reportado que la PLA 2 es menos neurotóxica si no está acompañada por Ctp. Dicho comple...

Crotalus durissus terrificus (Cdt) main toxic compound of its venom is crotoxin (almost 50% of dry venom), is a β-neurotoxin composed by two subunits non-covalently bonded, one inactive and the other a phospholipase A2. Crotamine (Ctm) is nonenzymatic (about 12% of the dry weight of the crude venom of crotamine-positive Cdt) and both have interesti...

Bevacizumab is a vascular endothelial growth factor (VEGF)-directed monoclonal antibody (mAb) used for the treatment of several human cancers. Given that bevacizumab is administered intravenously, it must have extremely high purity, which is achieved by purification with protein A affinity chromatography (AC). However, protein A is a very expensive...

Human pathogenic gram‐negative bacteria, such as enteropathogenic Escherichia coli (EPEC), rely on type III secretion systems (T3SS) to translocate virulence factors directly into host cells. The coiled‐coil domains present in the structural proteins of T3SS are conformed by amphipathic alpha‐helical structures that play an important role in the pr...

In the last few years many novel and alternative protein purification protocols have been designed using immobilized short-peptides or peptidomimetics as ligands for affinity chromatography. These ligands are easy to synthesize and less expensive than protein based ligands, such as monoclonal antibodies or protein A, thus enabling low-cost industri...

Peptide KVPLITVSKAK was selected to design a synthetic ligand for affinity chromatography purification of recombinant human follicle stimulating hormone (rhFSH), based on the interaction of the hormone with the exoloop 3 of its receptor. The peptide was acetylated to improve its stability to degradation by exopeptidases. A cysteine was incorporated...

Recombinant human growth hormone (rhGH) is used for the treatment ofseveral pathologies, most of them related to growth. Although differentexpression systems can be used for its production, the milk from transgeniccows is one of the most interesting due to the high rhGH level achieved (5 g/L).We have designed and synthesized short peptides (9 or 10...

Usually, diphteria toxin concentration and purification is performed after detoxification due to its high danger. In this work, an alternative diphteria toxoid (DTx) concentration and purification method by affinity chromatography is proposed. Screening of 19 triazinic dyes for selecting the best ligand for DTx concentration and purification by aff...

Nowadays, treatment with specific antivenins is considered the only cure for snakebites accidents. However, access to antivenom obstructs the successful implementation of the World Health Organization international guidelines. In the last few years, natural organic compounds, peptides and proteins with the ability to inhibit snake toxins and obtain...

Los péptidos antimicrobianos (AMPs por sus siglas en inglés) son pequeñas moléculas de menos de 50 aminoácidos, principalmente carga positiva e importantes propiedades antibacterianas y antifúngicas. Se cree que el principal mecanismo de acción contra los diferentes patógenos es la ruptura de membranas, que puede darse mediante tres modos de acción...

Los anticuerpos monoclonales (mAbs) tienen un enorme y creciente interés en la industria farmacéutica. Actualmente hay más de 70 mAbs terapéuticos aprobados por la Food and Drug Administration (FDA). Su proceso de producción industrial consiste en una etapa de crecimiento de las células productoras del mAb en un biorreactor y en una etapa de recupe...

RESUMEN 32 SUMMARY: Peptides with the ability to inhibit snake venom toxic components 32 INTRODUCCIÓN 33 PÉPTIDOS COMO POSIBLES INHIBIDORES DE LA ACCIÓN TÓXICA DE LOS COMPUESTOS DEL VENENO DE SERPIENTE 35 PÉPTIDOS QUE INHIBEN LAS SVMP PRESENTES EN EL VENENO DE SERPIENTES 36 PÉPTIDOS QUE INHIBEN LA FOSFOLIPASA A2 PRESENTE EN EL VENENO DE SERPIENTES...

Recombinant human growth hormone (rhGH) is used for the treatment of several pathologies, most of them related to growth. Although different expression systems can be used for its production, the milk from transgenic cows is one of the most interesting due to the high rhGH level achieved (5 g/L). We have designed and synthesized short peptides (9 o...

Although peptides are used as affinity chromatography ligands, they could be digested by proteases. Usually, peptide stability is evaluated in solution, which differs from the resin-bounded peptide behavior. Furthermore, the study of the degradation products requires purification steps before analysis. Here, we describe an easy method to assess imm...

Since introduction of sinapinic acid (SA) and α-cyano-4-hydroxycinnamic acid as matrices successful application of matrix assisted laser desorption/ionization mass spectrometry started for protein/polypeptides. Both show some limitations in short peptide analysis because matrix clusters are quite abundant. Cinnamics currently used are E-cinnamics....

Introducción: El objetivo de este trabajo fue implementar tecnologías de la información y la comunicación (TIC) a nivel de posgrado. En este caso particular se usó USINA, un simulador para la toma de decisiones diseñado por el Centro de Innovaciones en Tecnología y Pedagogía (CITEP), de la Universidad de Buenos Aires. Ésta permite trabajar con narr...

Combinatorial library screening coupled to mass spectrometry (MS) analysis is a practical approach to identify useful peptides. Cyclic peptides can have high biological activity, selectivity, and affinity for target proteins, and high stability against proteolytic degradation. Here we describe two strategies to prepare combinatorial libraries suita...

In press: Protocols to synthesis cyclic libraries

Solid phase screenings of one bead one compound (OBOC) libraries have been widely used to find ligands with pharmacological and analytical uses, and to purify or detect proteins in complex mixtures. To improve library screening, in the last years various strategies have been developed to avoid the selection of false positive beads and to obtain sel...

Short cyclic peptides have a growing interest in therapeutic, diagnostic and affinity chromatography applications due to their higher selectivity and resistance to enzymatic degradation than their linear counterparts. One-bead-one-peptide libraries combined with mass spectrometry allow the screening and identification of suitable ligands for any ta...

Short peptides are excellent ligands for affinity chromatrography. Divide-couple-recombine method allows obtaining a peptide library with all possible combinations of the amino acids in the form of "one bead-one peptide". In this work we designed a two-stage library screening method for peptide ligands selection. The first library screening was per...

We describe a method to develop affinity chromatography matrices with short peptide ligands for protein purification. The method entitles the following: (a) synthesis of a combinatorial library on the hydromethylbenzoyl (HMBA)-ChemMatrix resin by the divide-couple-recombine (DCR) method using the Fmoc chemistry, (b) library screening with the prote...

One-bead-one-peptide libraries allow the screening of suitable ligands for any target protein. Short cyclic peptides are ideal ligands for affinity chromatography due to their high affinity and selectivity for the target protein and stability against proteases. We designed a library synthesis strategy to facilitate the identification of cyclic pept...

Transglycosylation potential of the fungal diglycosidase α-rhamnosyl-β-glucosidase was explored. The biocatalyst was shown to have broad acceptor specificity toward aliphatic and aromatic alcohols. This feature allowed the synthesis of the diglycoconjugated fluorogenic substrate 4-methylumbelliferyl-rutinoside. The synthesis was performed in one st...

Native potato starch was acetylated and characterized. The influence of this chemical modification on different properties of the starch was studied. The characterization included the molecular weight, thermal properties, crystallinity, amylose content, swelling behavior, and pasting and rheological properties. The chemical modification induced sma...

The polycondensation of (3-methacryloxypropyl)-trimethoxysilane in acidic conditions using different methacrylate monomers as reactive solvents resulted in incompletely condensed methacrylate-functionalized silsesquioxanes with a very large fraction of intramolecular cycles. UV-MALDI-TOF-MS analysis demonstrated that the species present after 2week...

The effect of Ca(2+) (and Mg(2+)) and the disodium salt of ethylenediaminetetraacetic acid (EDTA), a well known Ca(2+) (and Mg(2+)) chelating agent, on the volatilization/ionization of carbohydrates by using electrospray ionization mass spectrometry has been studied. Model compounds such as maltoses (maltose to maltoheptaose), beta-cyclodextrins (b...

Nanoparticles (NPs) of diamond, titanium dioxide, titanium silicon oxide, barium strontium titanium oxide, and silver (Ag) were examined for their potential as MALDI matrixes for direct laser desorption/ionization of carbohydrates, especially fructans, from plant tissue. Two sample preparation methods including solvent-assisted and solvent-free (dr...

Optimization of bead analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) after the screening of one-bead-one-peptide combinatorial libraries was achieved, involving the fine-tuning of the whole process. Guanidine was replaced by acetonitrile (MeCN)/acetic acid (AcOH)/water (H(2)O), improving matri...

Optimization of bead analysis by matrix-assisted laser desorption/ionization time-of-flight mass spec-trometry (MALDI–TOF–MS) after the screening of one-bead–one-peptide combinatorial libraries was achieved, involving the fine-tuning of the whole process. Guanidine was replaced by acetonitrile (MeCN)/acetic acid (AcOH)/water (H 2 O), improving matr...

To screen one-bead-one-compound (OBOC) combinatorial libraries, tens of thousands to millions of compound beads are first mixed with a target molecule. The beads that interact with this molecule are then identified and isolated for compound structure determination. Here we describe an OBOC peptide library screening using streptavidin (SA) as probe...

Bovine seminal plasma was submitted to chromatography on Con A-Sepharose. The "noninteracting", "weakly-interacting" and "strongly-interacting" fractions were analyzed through UV-MALDI-TOF MS together with a subfraction of the "non-interacting" material, using sinapinic acid (SA) as matrix. The spectra were obtained in linear positive mode in the 4...