Search

Spider venom contains various peptides and proteins, which can be used for pharmacological applications. Finding novel therapeutic strategies against neurodegenerative diseases with the use of purified peptides and proteins, extracted from spiders can be greatly precious. Neurodegenerative diseases are rapidly developing and expanding all over the world. Excitotoxicity is a frequent condition amongst neuro-degenerative disorders. This harmful process is usually induced through hyper-activation of N-Methyl-D-Aspartate (NMDA) receptor, and P/Q-type voltage-gated calcium channels (VGCCs). The omega-agatoxin-Aa4b is a selective and strong VGCCblocker. This study aimed to investigate the effects of this blocker on the NMDA-induced memory and learning defect in rats. For this purpose, nineteen spiders of the funnel-weaver Agelena orientalis species were collected. The extracted venom was lyophilized andpurified through gel-filtration chromatography, and capillary electrophoresis techniques. Subsequently, mass spectrometry (HPLC-ESI-MS) was used for identification of this bio-active small protein. Afterward, the effect of the omega-agatoxin-Aa4b (2 μg, intra-cornu ammonis-3 of the hippocampus) on the NMDA-induced learning and memory deficits in rats was evaluated. Learning and memory performances were evaluated by the use of passive avoidance test. For synaptic quantification and memory function the amount of calcium/calmodulin-dependent protein kinase ІІ (CaCdPKІІ) gene expression was measured using the Real-time PCR technique. To compare the experimental groups, hematoxylin and eosin (H&E) staining of hippocampus tissues was performed. Our results rendered that the omega-Agatoxin-Aa4b treatment can ameliorate and reverse the learning and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus. [ABSTRACT FROM AUTHOR]

The huntsman spiders' genus Eusparassus are apex arthropod predators in desert ecosystems of the Afrotropical and Palearctic ecoregions. The Eusparassus dufouri and E. walckenaeri clades are two distinct taxonomic, phylogenetic, and geographic units concerning morphology, molecular phylogeny, and spatial data; but little is known about their ecological niche. We applied the maximum-entropy approach and modelled ecologic niches of these two phylogenetically closely related clades. Ecological niches of the two clades were compared using identity and background tests and two different metrics, the Schooner's D and Warren's I. We also predicted the impacts of climate change on the distribution of the two clades. The results of the identity test showed that the ecological niches of the two clades were different in geographic space but were similar in environmental space. While results of the background test revealed that the ecological niches of the two clades were similar in geographic and environmental space. This indicated that "niche conservatism" had an important role over the evolutionary time of allopatric diversification. However, the normalized difference vegetation index vs. topographic heterogeneity had influenced the niches of the dufouri and walckenaeri clades, respectively. The analyses recovered that the two clades' climatically suitable habitats will increase under future climate (the year 2070). However, since the two clades are characterized by the narrow range of environmental optimum and the accordingly high limits of tolerance, they are vulnerable to climate change. [ABSTRACT FROM AUTHOR]