Synthetic angiotensin II peptide derivatives confer protection against cerebral and severe non-cerebral malaria in murine models.

Malaria can have severe long-term effects. Even after treatment with antimalarial drugs eliminates the parasite, survivors of cerebral malaria may suffer from irreversible brain damage, leading to cognitive deficits. Angiotensin II, a natural human peptide hormone that regulates blood pressure, has been shown to be active against Plasmodium spp.

Biotechnological Potential of Pine Nuts Extract and the Cysteine Protease Inhibitor AaCI-2S.

Protease inhibitors are involved in the regulation of endogenous cysteine proteases during seed development and play a defensive role because of their ability to inhibit exogenous proteases such as those present in the digestive tracts of insects. seeds, which can be used in human and animal feed, were investigated for their potential for the development of agricultural biotechnology and in the field of human health. In the pine nuts extract, which blocked the activities of cysteine proteases, it was detected potent insecticidal activity against termites () belonging to the most abundant termite genus in tropical regions.

Two Tachykinin-Related Peptides with Antimicrobial Activity Isolated from Hemolymph.

Antimicrobial peptides and proteins (AMPs) are molecules that can interact with microbial cells and lead to membrane disruption or intracellular molecule interactions and death. Several molecules with antimicrobial effects also present other biological activities. One such protein group representing the duplicity of activities is the tachykinin family.

The interaction of sodium trimetaphosphate with collagen I induces conformational change and mineralization that prevents collagenase proteolytic attack.

Objectives: This study evaluated the cell viability and expression of different major genes involved in mineralization in odontoblast-like cells exposed to sodium trimetaphosphate (STMP). It was also investigated the influence of STMP on the rate of calcium phosphate crystal growth, its anti-proteolytic action against the enzymatic degradation of type I collagen, the binding mechanism of STMP to collagen fibrils, and the potential mechanism to induce collagen stabilization.

Methods: Immortalized rat odontoblast MDPC-23 cells were cultured.

IsCT-based analogs intending better biological activity.

IsCT1-NH is a cationic antimicrobial peptide isolated from the venom of the scorpion Opisthacanthus madagascariensis that has a tendency to form an α-helical structure and shows potent antimicrobial activity and also inopportunely shows hemolytic effects. In this study, five IsCT1 (ILGKIWEGIKSLF)-based analogs with amino acid modifications at positions 1, 3, 5, or 8 and one analog with three simultaneous substitutions at the 1, 5, and 8 positions were designed. The net charge of each analog was between +2 and +3.

Antimicrobial activity and mechanism of action of a novel peptide present in the ecdysis process of centipede Scolopendra subspinipes subspinipes.

One of the most important cellular events in arthropods is the moulting of the cuticle (ecdysis). This process allows them to grow until they reach sexual maturity. Nevertheless, during this stage, the animals are highly exposed to pathogens.

Sarconesin II, a New Antimicrobial Peptide Isolated from Excretions and Secretions.

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs).

Structure of Rhoptry Neck Protein 2 is essential for the interaction in vitro with Apical Membrane Antigen 1 in Plasmodium vivax.

Background: In several Apicomplexa, the formation of moving junctions (MJs) at the interface between the external membranes of the invading parasite and the host cell is essential for the process of parasite invasion. In Plasmodium falciparum and Toxoplasma gondii, the MJ is composed of the Apical Membrane Antigen 1 (AMA1) and Rhoptry Neck Proteins (RONs) complex; specifically, AMA1 interacts with RON2 during host cell invasion.

Methods: Recombinant proteins based on Plasmodium vivax RON2 (A2033-P2100) and its synthetic peptide fragments, one cyclic and one linear, based on PvRON2 (D2035-T2074) were generated and used to evaluate the interaction with P.

Angiotensin II-derived constrained peptides with antiplasmodial activity and suppressed vasoconstriction.

Angiotensin II (Ang II) is a natural mammalian hormone that has been described to exhibit antiplasmodial activity therefore constituting a promising alternative for the treatment of malaria. Despite its promise, the development of Ang II as an antimalarial is limited by its potent induction of vasoconstriction and its rapid degradation within minutes. Here, we used peptide design to perform targeted chemical modifications to Ang II to generate conformationally restricted (disulfide-crosslinked) peptide derivatives with suppressed vasoconstrictor activity and increased stability.

Identification and characterisation of serine protease inhibitors from Araucaria angustifolia seeds.

Araucaria angustifolia seeds are characterised by a relatively high content of starch and protein. This study aimed to verify the presence of α-amylase inhibitors in the seeds and to characterise a trypsin inhibitor found in the embryo tissues. Inhibitor purification was carried out by the saline extraction of proteins, acetone precipitation and affinity chromatography.

Angiotensin II analogues with N-terminal lactam bridge cyclization: an overview on AT receptor activation and tachyphylaxis.

Angiotensin II (AngII) is the final active product of the renin enzymatic cascade, which is responsible for sustaining blood pressure. To investigate the effect of N-terminal cyclization on AT activation and tachyphylaxis, we designed conformationally constrained analogues with an i-(i + 1) lactam bridge. All analogues presented the same binding coefficient and tachyphylactic index, but some of them such as Cyclo (0-1a) [Glu , endo-(Lys )]-AngII and Cyclo (0-1a) [Asp , endo-(Orn )]-AngII showed higher potency.

Evidences for the action mechanism of angiotensin II and its analogs on Plasmodium sporozoite membranes.

Malaria is an infectious disease responsible for approximately one million deaths annually. Oligopeptides such as angiotensin II (AII) and its analogs are known to have antimalarial effects against Plasmodium gallinaceum and Plasmodium falciparum. However, their mechanism of action is still not fully understood at the molecular level.

New linear antiplasmodial peptides related to angiotensin II.

Background: Antiplasmodial activities of angiotensin II and its analogues have been extensively investigated in Plasmodium gallinaceum and Plasmodium falciparum parasite species. Due to its vasoconstrictor property angiotensin II cannot be used as an anti-malarial drug.

Methods: This work presents the solid-phase syntheses and liquid chromatography and mass spectrometry characterization of ten linear peptides related to angiotensin II against mature P.

Anti-plasmodial activity of bradykinin and analogs.

To find effective new candidate antimalarial drugs, bradykinin and its analogs were synthesized and tested for effectiveness against Plasmodium gallinaceum sporozoites and Plasmodium falciparum on erythrocytes. Among them, bradykinin and its P2 analog presented high activity against Plasmodium gallinaceum, but they degrade in plasma. On the other hand, RI-BbKI did not degrade and reached high activity.

Conformational and biological properties of Bauhinia bauhinioides kallikrein inhibitor fragments with bradykinin-like activities.

Proteinase inhibitors extracted form medicinal plants are an interesting source of new drugs. Modifications in the structure of some of this kind of macromolecules could also lead to compounds of interesting biological properties. In this work, we synthesized and tested one fragment containing the reactive site of the Bauhinia bauhinioides kallikrein inhibitor (BbKI), denoted BbKI51-62 , and a related analog (P2 ) in which a proline residue was inserted in order to mimic the N-terminal region of the bradykinin molecule.

Effects of the angiotensin II Ala-scan analogs in erythrocytic cycle of Plasmodium falciparum (in vitro) and Plasmodium gallinaceum (ex vivo).

The anti-plasmodium activity of angiotensin II and its analogs have been described in different plasmodium species. Here we synthesized angiotensin II Ala-scan analogs to verify peptide-parasite invasion preservation with residue replacements. The analogs were synthesized by 9-fluorenylmethoxycarbonyl (Fmoc) and tert-butyloxycarbonyl (t-Boc) solid phase methods, purified by liquid chromatography and characterized by mass spectrometry.

Antiplasmodial activity study of angiotensin II via Ala scan analogs.

Angiotensin II (AII) as well as analog peptides shows antimalarial activity against Plasmodium gallinaceum and Plasmodium falciparum, but the exact mechanism of action is still unknown. This work presents the solid-phase synthesis and characterization of eight peptides corresponding to the alanine scanning series of AII plus the amide-capped derivative and the evaluation of the antiplasmodial activity of these peptides against mature P. gallinaceum sporozoites.

Highly potential antiplasmodial restricted peptides.

Malaria is an infectious disease responsible for approximately one million deaths annually. The antimalarial effects of angiotensin II and its analogs against Plasmodium gallinaceum and P. falciparum have recently been reported.