New drugs are urgently required for the treatment of amoebiasis, leishmaniasis, malaria and trypanosomiasis. In this review the potential of natural plant products as a source of antiprotozoal drugs is discussed with respect to biochemical differences between protozoa and hosts. Some of the ways in which pathogenic protozoa differ biochemically from their human hosts are described, and the modes of action of some antiprotozoal drugs which exploit these differences are mentioned. A selection of natural products of plant origin (alkaloids, terpenes, quinones and miscellaneous compounds) is illustrated with emphasis on their modes of action and potential for the development of selective antiprotozoal agents.

Natural products and the development of selective antiprotozoal drugs

The protozoan parasite Entamoeba histolytica is the causative agent of amoebic dysentery. It is prevalent in developing countries that cannot prevent its fecal–oral spread and ranks second in worldwide causes of morbidity by parasitic infection. Improvements in sanitation would help curb disease spread. However, a lack of significant progress in this area has resulted in the need for a better understanding of the molecular and cellular biology of pathogenesis in order to design novel methods of disease treatment and prevention. Recent insight into the cellular mechanisms regulating virulence of E. histolytica has indicated that processes such as endocytosis, secretion, host cell adhesion and encystation play major roles in the infectious process. This review focuses on components of the molecular machinery that govern these cellular processes and their role in virulence, and discusses how an understanding of this might reveal opportunities to interfere with E. histolytica infection.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1462399405009622

Cellular and molecular mechanisms that underlie Entamoeba histolytica pathogenesis: prospects for intervention.

Protein sequencing and identification using tandem mass spectrometry. Edited by Michael Kinter, Nicholas E. Sherman, published by Wiley-Interscience Series on Mass Spectrometry, 2000, 301 p.

Summary
Three peptides with pore-forming activity were isolated from the cytoplasmic granules of pathogenic Entamoeba histolytica by acidic extraction, gel filtration and reversed-phase high-performance liquid chromatography. Partial amino acid sequence analysis of the three active peptides revealed that the most abundant of them was amoebapore and the other two were isoforms thereof. Cloning and sequencing of genomic DNA resolved the amino acid sequence of the two newly recognized peptides. The three peptides designated amoebapores A, B and C were found to have the same molecular size but to differ markedly in their primary structure, although all six cysteine residues are conserved. Despite sequence divergence, structural implications predict for the three peptides a similar amphipathic α-helical conformation stabilized by disulphide bonds. All three isoforms exhibit pore-forming activity toward lipid vesicles, but they differ in their kinetics. They also are capable of perturbing the integrity of bacterial cytoplasmic membranes and thereby kill Gram-positive bacteria. The amoebapores represent a distinct family of membrane-active peptides that may function intracellularly as antimicrobial agents but may also confer cytolytic activity on the parasite.

Amoebapores, a family of membranolytic peptides from cytoplasmic granules of Entamoeba histolytica: isolation, primary structure, and pore bacterial cytoplasmic membranes

Palladium(II) complexes of NS donor ligandsderived from S-methyl-dithiocarbazate, S-benzyldithiocarbazateand thiosemicarbazide as antiamoebic agents

Entamoeba histolytica: Cell cycle and nuclear division

Isolation and characterization of Entamoeba histolytica mutants resistant to emetine.

Molecular karyotype of related clones of Entamoeba histolytica.

Osteoarthritis (OA) is characterized by degeneration of articular cartilage. Animal models of OA induced are a widely used tool in the study of the pathogenesis of disease. Several proteomic techniques for selective extraction of proteins have provided protein profiles of chondrocytes and secretory patterns in normal and osteoarthritic cartilage, including the discovery of new and promising biomarkers. In this proteomic analysis to study several proteins from rat normal articular cartilage, two-dimensional electrophoresis and mass spectrometry (MS) were used. Interestingly, latexin (LXN) was found. Using an immunohistochemical technique, it was possible to determine its localization within the chondrocytes from normal and osteoarthritic articular cartilage. In this study, 147 proteins were visualized, and 47 proteins were identified by MS. A significant proportion of proteins are involved in metabolic processes and energy (32%), as well as participating in different biological functions including structural organization (19%), signal transduction and molecular signaling (11%), redox homeostasis (9%), transcription and protein synthesis (6%), and transport (6%). The identified proteins were assigned to one or more subcellular compartments. Among the identified proteins, we found some proteins already recognized in other studies such as OA-associated proteins. Interestingly, we identified LXN, an inhibitor of mammalian carboxypeptidases, which had not been described in articular cartilage. Immunolabeling assays for LXN showed a granular distribution pattern in the cytoplasm of most chondrocytes of the middle, deep and calcified zones of normal articular cartilage as well as in subchondral bone. In osteoarthritic cartilage, LXN was observed in superficial and deep zones. This study provides the first proteomic analysis of normal articular cartilage of rat. We identified LXN, whose location was demonstrated by immunolabeling in the chondrocytes from the middle, deep and calcified zones of normal articular cartilage, and superficial and deep zones of osteoarthritic cartilage.

/pdf/identification-of-latexin-by-a-proteomic-analysis-in-rat-fp5zzuc8f4.pdf

Identification of latexin by a proteomic analysis in rat normal articular cartilage

There are numerous pathogenic microorganisms which cause important losses in fresh water fish cultures. Fungi and Oomycetes are included among these pathogens. Due to there are hot treatments to eliminate this pathogens in the culture tanks, it is important to design methods to detect and prevent their development. Laspite of in the last years, a number of cheap diagnostics tools, based on polymerase chain reaction (PCR) have been developed there are not methods for fungi/oomycete detection. The product BIAADETECT, developed from the Homoptera Dactylopius coccus, reacts contact with celular wall compounds of fungi like zymosan and b 1-3 glucans, which suggests a possible application as a predictor of pathogens in water.

https://dialnet.unirioja.es/descarga/articulo/2986635.pdf

Detección de hongos y oomycetos en cultivos de peces dulceacuícolas empleando el kit BIAADETECT, producto desarrollado a partir del homóptero Dactylopius coccus.

Fidel de la Cruz Hernández Hernández

Papers

Entamoeba histolytica: Cell cycle and nuclear division

Isolation and characterization of Entamoeba histolytica mutants resistant to emetine.

Molecular karyotype of related clones of Entamoeba histolytica.

Identification of latexin by a proteomic analysis in rat normal articular cartilage

Detección de hongos y oomycetos en cultivos de peces dulceacuícolas empleando el kit BIAADETECT, producto desarrollado a partir del homóptero Dactylopius coccus.