Antigiardial Activity of Acetylsalicylic Acid Is Associated with Overexpression of HSP70 and Membrane Transporters

Giardia lamblia is a flagellated protozoan responsible for giardiasis, a worldwide diarrheal disease. The adverse effects of the pharmacological treatments and the appearance of drug resistance have increased the rate of therapeutic failures. In the search for alternative therapeutics, drug repositioning has become a popular strategy. Acetylsalicylic acid (ASA) exhibits diverse biological activities through multiple mechanisms. However, the full spectrum of its activities is incompletely understood. In this study we show that ASA displayed direct antigiardial activity and affected the adhesion and growth of trophozoites in a time-dose-dependent manner. Electron microscopy images revealed remarkable morphological alterations in the membrane, ventral disk, and caudal region. Using mass spectrometry and real-time quantitative reverse transcription (qRT-PCR), we identified that ASA induced the overexpression of heat shock protein 70 (HSP70). ASA also showed a significant increase of five ATP-binding cassette (ABC) transporters (giABC, giABCP, giMDRP, giMRPL and giMDRAP1). Additionally, we found low toxicity on Caco-2 cells. Taken together, these results suggest an important role of HSPs and ABC drug transporters in contributing to stress tolerance and protecting cells from ASA-induced stress.

Nek8445, a protein kinase required for microtubule regulation and cytokinesis in Giardia lamblia

Here we study the role of Nek8445 in regulating cell division and microtubule array organization in Giardia. Depletion of Nek8445 results in 87% of cells being stalled or blocked in cytokinesis. Nek8445 regulates ventral disk organization, funis formation, axoneme exit, and cell shape, all of which contribute to the observed cytokinesis defects.

Taxonomic review of dwarf species of Eumicrotremus (Actinopterygii: Cottoidei: Cyclopteridae) with descriptions of two new species from the western North Pacific

A taxonomic review of the dwarf species of the genus Eumicrotremus (Actinopterygii: Cottoidei: Cyclopteridae), previously recognized as belonging to Lethotremus, established the existence of three species, viz. Eumicrotremus awae (Jordan and Snyder, 1902), Eumicrotremus uenoi sp. nov., and Eumicrotremus jindoensis sp. nov., from the western North Pacific. Eumicrotremus awae, known from the Pacific coast of Honshu Is. (Chiba southward to Mie), is characterized by the absence of spiny tubercles or fleshy papillae on the body, the anterior three mandibular pores each with a barbel-like tube, interorbital and suborbital pores usually absent, the opercular flap rounded, many papillae present on the ventral disk and the caudal-fin relatively short, 21.0–30.5% of SL (standard length). Eumicrotremus uenoi, known from the western coast of Honshu Is. and the southern coast of Korean Peninsula, is characterized by the absence of spiny tubercles or fleshy papillae on the body (or weak if present), the anterior three mandibular pores each with a barbel-like tube, interorbital and suborbital pores usually present, the opercular flap rounded, the ventral disk with many papillae and the caudal-fin relatively short, 19.5–31.4% of SL. Eumicrotremus jindoensis, known from the southwestern coast of Korean Peninsula, and the coasts of Yellow Sea, is characterized by a smooth soft body, triangular opercular flap, absence of papillae on the ventral disk and a long caudal fin, 32.7–42.1% of SL. Sequence variations of the mictochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) and the nuclear myh6 genes supported the validity of the three species.

Amphicutis stygobita, a new genus and new species of brittle star (Echinodermata: Ophiuroidea: Ophiurida: Amphilepididae) found in Bernier Cave, an anchialine cave on San Salvador Island, Bahamas

Amphicutis stygobita is a new genus and new species of ophiuroid found in Bernier Cave, an anchialine cave on San Salvador Island, Bahamas. The species is small (disk diameter 3–4 mm) with short arms (2–2.5X disk diameter). Dorsal disk features include imbricated scales, and oval radial shields separated by a column of scales. Ventral disk features include imbricated scales, genital scales flat and thin, no bursal sacs, second tentacle pore of oral frame outside mouth slit, oral shields small ovals similar in appearance to disk scales, two to three oral papillae per jaw side with the proximal papillae usually in the infradental position, and ventral tooth at the apex of each jaw broadly rounded. The arms are the most distinctive feature. Dorsal arm plates are small diamond-oval shaped and separated from one another by a gap equal to the arm plate length. Ventral arm plates are small figure-8 shaped and separated from one another by a gap equal to the arm plate length. Lateral arm plates meet medially on dorsal and ventral sides and make up most of an arm segment. Each lateral arm plate bears two arm spines. Disk and arms are often formed by soft tissue outlining plates and scales, but lacking significant calcification. A raised skin persists after calcification, from which the genus name derives. The species is named for its aquatic cave-dwelling habit, apparently endemic to a single cave, and may be unique among ophiuroids in being restricted to a cave environment.

Ultrastructural localization of giardins to the edges of disk microribbons of Giarida lamblia and the nucleotide and deduced protein sequence of alpha giardin.

The giardins are a group of 29-38-kD proteins in the ventral disk of the protozoan parasite Giardia lamblia. The disk attaches the parasite to the host's intestinal epithelium and is composed of parallel, coiled microtubules that are adjacent to the ventral plasma membrane and from which processes called microribbons extend into the cytoplasm; the microribbons are connected by crossbridges. G. lamblia cytoskeletons, consisting of disks and attached flagella, were isolated and used to show that the 29-38-kD proteins separate into five bands by one-dimensional electrophoresis and into 23 species by two-dimensional analysis. Rabbit antibodies raised against a 33-kD protein band, purified by one-dimensional gel electrophoresis and shown to contain three proteins by two-dimensional electrophoresis, recognized 17 proteins by two-dimensional immunoblot analysis. By immunofluorescence these antibodies reacted with the ventral disk but not with the flagella in isolated cytoskeletons. Electron microscopy revealed that the anti-giardin antibodies bound to the edges of the microribbons but not to the microtubules, crossbridges, or other, nondisk structures. Antibodies to tubulin reacted with both the disk and flagella in isolated cytoskeletons but bound only to the microtubules in these structures. The amino-terminal sequence of the 33-kD immunogen was determined and used to construct a DNA oligomer, and the oligomer was used to isolate the alpha giardin gene. The gene was used to hybrid select RNA, and the in vitro translation product from this RNA was precipitated by the antibodies against the 33-kD immunogen. The gene sequence was a single open reading frame of 885 nucleotides that predicted a protein of 33.8 kD. The protein sequence is unique, having no significant homology to two other giardin sequences or to any sequences within the Protein Identification Resource. It is predicted to be 82% alpha helical. The downstream sequence of the gene indicates that the sequence AGT-PuAA is located six to nine nucleotides beyond the stop codon in all protein-encoding genes of G. lamblia that have been sequenced and reported to date.