Purification of Chromate(VI) Reductase from Lichen photobiont, Trebouxia erici and its Effect on Wastewaters.

Chromate (VI) reductase (CR) was isolated and purified from soluble extracts obtained from lichen photobiont, Trebouxia erici by salt gradient and sequential chromatographic methods. The soluble extract was fractionated by ammonium sulphate precipitation, dialysed and applied onto CM-Sephadex ion-exchange column. The active fractions were pooled and chromatographed on a SephadexG-75 column .Electrophoresis on SDS-PAGE analysis of the partially purified chromate(VI) reductase revealed two bands with  molecular weights of 39 kDa and 63 kDa . The enzyme had maximum activity at pH 6 and an optimum temperature of 40oC. The enzyme was stable between pH 4 and 7. Double reciprocal plots of initial velocity data, using NADH as substrate, gave a KM value of 118 μM and Vmax of 0.173 μmol/min/mg respectively . Studies on the effect of chromium reductase on synthetic wastewater shows that chromate(VI) reductase (CR) was effective in the reduction of over 65% of Cr (VI) to Cr (III) in 4h. The bioremediation potential of chromate(VI) by lichen was discussed. Keywords: Chromate(VI) reductase, purification, bioremediation, wastewater

A novel Plasmodium falciparum rhoptry associated adhesin mediates erythrocyte invasion through the sialic-acid dependent pathway

Erythrocyte invasion by Plasmodium falciparum merozoites is central to blood-stage infection and malaria pathogenesis. This intricate process is coordinated by multiple parasite adhesins that bind erythrocyte receptors and mediate invasion through several alternate pathways. P. falciparum expresses 2700 genes during the blood-stages, of which the identity and function of many remains unknown. Here, we have identified and characterized a novel P. falciparum rhoptry associated adhesin (PfRA) that mediates erythrocyte invasion through the sialic-acid dependent pathway. PfRA appears to play a significant functional role as it is conserved across different Plasmodium species. It is localized in the rhoptries and further translocated to the merozoite surface. Both native and recombinant PfRA specifically bound erythrocytes in a sialic-acid dependent, chymotrypsin and trypsin resistant manner, which was abrogated by PfRA antibodies confirming a role in erythrocyte invasion. PfRA antibodies inhibited erythrocyte invasion and in combination with antibodies against other parasite ligands produced an additive inhibitory effect, thus validating its important role in erythrocyte invasion. We have thus identified a novel P. falciparum adhesin that binds with a sialic acid containing erythrocyte receptor. Our observations substantiate the strategy to block P. falciparum erythrocyte invasion by simultaneously targeting multiple conserved merozoite antigens involved in alternate invasion pathways

Molecular Characterization and Immuno-Reactivity Patterns of a Novel Plasmodium falciparum Armadillo-Type Repeat Protein, PfATRP.

Nearly half of the genes in the Plasmodium falciparum genome have not yet been functionally investigated. We used homology-based structural modeling to identify multiple copies of Armadillo repeats within one uncharacterized gene expressed during the intraerythrocytic stages, PF3D7_0410600, subsequently referred to as P. falciparum Armadillo-Type Repeat Protein (PfATRP). Soluble recombinant PfATRP was expressed in a bacterial expression system, purified to apparent homogeneity and the identity of the recombinant PfATRP was confirmed by mass spectrometry. Affinity-purified α-PfATRP rabbit antibodies specifically recognized the recombinant protein. Immunofluorescence assays revealed that α-PfATRP rabbit antibodies reacted with P. falciparum schizonts. Anti-PfATRP antibody exhibited peripheral staining patterns around the merozoites. Given the localization of PfATRP in merozoites, we tested for an egress phenotype during schizont arrest assays and demonstrated that native PfATRP is inaccessible on the surface of merozoites in intact schizonts. Dual immunofluorescence assays with markers for the inner membrane complex (IMC) and microtubules suggest partial colocalization in both asexual and sexual stage parasites. Using the soluble recombinant PfATRP in a screen of plasma samples revealed that malaria-infected children have naturally acquired PfATRP-specific antibodies

Ethnopharmacology, Biological evaluation and Chemical composition of Boswellia dalzielii Hutch: A Review

The Burseraceae family consists of 18 genera and 540 species. Boswellia dalzielii is a medicinal plant used in tropical and subtropical areas for the treatment and management of various ailments. Despite the medicinal value of B. dalzielii, there is no comprehensive documentation. The study aimed to review the ethnopharmacology, biological evaluation and chemical composition of B. dalzielii. Scopus, Web of Science, BioMed Central, Science Direct, PubMed, Springer Link, and Google Scholar were searched to find published articles. The results showed that the leaves, stem bark, and root of B. dalzielii have been traditionally used in Nigeria, Cameroon, Burkina Faso, Benin, Sudan, and Guinee for the treatment and management of antirheumatic, antispasmodic, analgesic, antiseptic, hypotensive, malarial mental illness, ulcer, pain, and fever. It is also found that leaves, stem bark, and root have antioxidant, antibacterial, antifungal, and antimalarial properties with stembark having the highest activity. Chemically, it was revealed the leaf has high contents of monoterpenes hydrocarbons with alpha-pinene as the major compound. The species were largely studied in vitro, according to the literature survey. A well-designed clinical experiment is required to obtain conclusive evidence on the efficacy of stembark. The standard dose and safety of the stembark should be established

Antimalaria Effect of the Ethanolic Stem Bark Extracts of Ficus platyphylla Del

The antimalarial effect of the ethanolic stem bark extract of Ficus platyphylla Del was evaluated against Plasmodium berghei infection in mice. Nontreated, experimental control mice died of fulminant parasitemia from day 7 to 9 post-infection but mice treated with the extract at 300 mg/kg showed markedly reduced parasitaemia bouts of 43.50% and a mean survival time of 28 days postinfection. The plant extract prevented a drastic reduction in PCV showing its efficacy in ameliorating anaemic conditions in Plasmodium berghei-infected mice. Histological examination of liver tissues of treated and untreated mice further supports the antimalaria potential of this plant. This observation validates the traditional use of this plant for the treatment of malaria

Elucidating the possible mechanism of action of some pathogen box compounds against Leishmania donovani.

Leishmaniasis is one of the Neglected Tropical Diseases (NTDs) which is closely associated with poverty and has gained much relevance recently due to its opportunistic coinfection with HIV. It is a protozoan zoonotic disease transmitted by a dipteran Phlebotomus, Lutzomyia/ Sergentomyia sandfly; during blood meals on its vertebrate intermediate hosts. It is a four-faceted disease with its visceral form being more deadly if left untreated. It is endemic across the tropics and sub-tropical regions of the world. It can be considered the third most important NTD after malaria and lymphatic filariasis. Currently, there are numerous drawbacks on the fight against leishmaniasis which includes: non-availability of vaccines, limited availability of drugs, high cost of mainstay drugs and parasite resistance to current treatments. In this study, we screened the antileishmanial activity, selectivity, morphological alterations, cell cycle progression and apoptotic potentials of six Pathogen box compounds from Medicine for Malaria Venture (MMV) against Leishmania donovani promastigotes and amastigotes. From this study, five of the compounds showed great promise as lead chemotherapeutics based on their high selectivity against the Leishmania donovani parasite when tested against the murine mammalian macrophage RAW 264.7 cell line (with a therapeutic index ranging between 19-914 (promastigotes) and 1-453 (amastigotes)). The cell cycle progression showed growth arrest at the G0-G1 phase of mitotic division, with an indication of apoptosis induced by two (2) of the pathogen box compounds tested. Our findings present useful information on the therapeutic potential of these compounds in leishmaniasis. We recommend further in vivo studies on these compounds to substantiate observations made in the in vitro study

Molecular Characterization and Immuno-Reactivity Patterns of a Novel Plasmodium falciparum Armadillo-Type Repeat Protein, PfATRP.

Nearly half of the genes in the Plasmodium falciparum genome have not yet been functionally investigated. We used homology-based structural modeling to identify multiple copies of Armadillo repeats within one uncharacterized gene expressed during the intraerythrocytic stages, PF3D7_0410600, subsequently referred to as P. falciparum Armadillo-Type Repeat Protein (PfATRP). Soluble recombinant PfATRP was expressed in a bacterial expression system, purified to apparent homogeneity and the identity of the recombinant PfATRP was confirmed by mass spectrometry. Affinity-purified α-PfATRP rabbit antibodies specifically recognized the recombinant protein. Immunofluorescence assays revealed that α-PfATRP rabbit antibodies reacted with P. falciparum schizonts. Anti-PfATRP antibody exhibited peripheral staining patterns around the merozoites. Given the localization of PfATRP in merozoites, we tested for an egress phenotype during schizont arrest assays and demonstrated that native PfATRP is inaccessible on the surface of merozoites in intact schizonts. Dual immunofluorescence assays with markers for the inner membrane complex (IMC) and microtubules suggest partial colocalization in both asexual and sexual stage parasites. Using the soluble recombinant PfATRP in a screen of plasma samples revealed that malaria-infected children have naturally acquired PfATRP-specific antibodies