8 Papers found (0.009 seconds)

George GH et al. (1985) Am J Trop Med Hyg "The onchocercal nodule: interrelationship of adult worms and blood vessels."

[

Am J Trop Med Hyg,

1985]

This study of onchocercal nodules reveals an intimate relationship between the cuticle of Onchocerca volvulus and the capillaries of the host. Perfusion of blood vessels with India ink and other special techniques reveal a proliferation of capillaries around the worms and communication between small vessels and the spaces around the worms. The space around the worm is continuous with the central fibrin lake. These findings, together with the fact that the worm's gut contains hemosiderin, suggest that the worm subverts the vascular reaction and causes within the nodule a controlled hemorrhage that serves the worm's nutritional needs. We believe this explains, in part, how worms survive in fibrous nodules for many years.

Ghoshdastider U et al. (2013) Cytoskeleton (Hoboken) "The expanding superfamily of gelsolin homology domain proteins."

Burtnick LD, Ghoshdastider U, Robinson RC, Popp D

[

Cytoskeleton (Hoboken),

2013]

The gelsolin homology (GH) domain has been found to date exclusively in actin-binding proteins. In humans, three copies of the domain are present in CapG, five copies in supervillin, and six copies each in adseverin, gelsolin, flightless I and the villins: villin, advillin and villin-like protein. Caenorhabditis elegans contains a four-GH-domain protein, GSNL-1. These architectures are predicted to have arisen from gene triplication followed by gene duplication to result in the six-domain protein. The subsequent loss of one, two or three domains produced the five-, four-, and three-domain proteins, respectively. Here we conducted BLAST and hidden Markov based searches of UniProt and NCBI databases to identify novel gelsolin domain containing proteins. The variety in architectures suggests that the GH domain has been tested in many molecular constructions during evolution. Of particular note is flightless-like I protein (FLIIL1) from Entamoeba histolytica, which combines a leucine rich repeats (LRR) domain, seven GH domains, and a headpiece domain, thus combining many of the features of flightless I with those of villin or supervillin. As such, the GH domain superfamily appears to have developed along complex routes. The distribution of these proteins was analyzed in the 343 completely sequenced genomes, mapped onto the tree of life, and phylogenetic trees of the proteins were constructed to gain insight into their evolution. 2013 Wiley Periodicals, Inc.

Connor DH et al. Rev Infect Dis "Pathologic changes of human onchocerciasis: implications for future research."

George GH, Gibson DW, Connor DH

[

Rev Infect Dis

]

Onchocerciasis--infection by Onchocerca volvulus--has four cardinal manifestations: dermatitis, subcutaneous nodules, sclerosing lymphadenitis, and eye disease. The first three are discussed here. The dermatitis begins when microfilariae degenerate in the dermis. This process is accompanied by inflammation, with degranulation of eosinophils and deposition of the major basic protein of the eosinophil granules on the cuticle of the microfilariae. So far as is known, the chronic effects of onchocerciasis are all a consequence of the degeneration of microfilariae. Subcutaneous nodules contain coiled adult worms and have an outer layer of fibrous scar and a central inflammatory cell exudate, which may cavitate. Perfusion of India ink reveals arborization of capillaries around adult worms, which derive nutrition from these networks. Onchocercal lymphadenitis is characterized initially by histiocytic hyperplasia and follicular atrophy and later by fibrosis and obstruction of lymph flow, a condition causing adenolymphocele ("hanging groin") and elephantiasis of the genitalia. Some patients appear to have immune tolerance to degenerating microfilariae, perhaps as a result of exposure in utero to microfilarial antigens in the maternal circulation. In contrast, other patients (Yemenites, for example) have a localized but intense response to a few microfilariae; these patients are hypersensitive--perhaps because they were not exposed to microfilarial antigens in utero. Autopsy data on infection of deep organs are limited.

Swindell WR (2009) Aging (Albany NY) "Heat shock proteins in long-lived worms and mice with insulin/insulin-like signaling mutations."

Swindell WR

[

Aging (Albany NY),

2009]

Heat shock proteins (HSPs) have proven to be effective tools for extending invertebrate lifespan, and in C. elegans daf-2 mutants, longevity resulting from loss of insulin/insulin-like signals is at least partly dependent upon elevated HSP expression. In mice, inhibition of the orthologous growth hormone/insulin-like growth factor I (GH/IGF-I) pathway has similar pro-longevity effects. A recent study, however, suggests that loss of GH/IGF-I signals in long-lived mice does not broadly elevate HSP expression, but in fact decreases HSP expression in many tissue types, such as liver and kidney. The contribution of chaperones to the longevity of long-lived mice with altered GH/IGF-I signals may therefore differ from that described in C. elegans daf-2 mutants. This result, in combination with other recent findings, underscores the possibility that systemic overexpression of chaperones will have dissimilar effects on longevity in vertebrate and invertebrate systems.

van Heemst D (2010) Aging Dis "Insulin, IGF-1 and longevity."

van Heemst D

[

Aging Dis,

2010]

It has been demonstrated in invertebrate species that the evolutionarily conserved insulin and insulin-like growth factor (IGF) signaling (IIS) pathway plays a major role in the control of longevity. In the roundworm Caenorhabditis elegans, single mutations that diminish insulin/IGF-1 signaling can increase lifespan more than twofold and cause the animal to remain active and youthful much longer than normal. Likewise, substantial increases in lifespan are associated with mutations that reduce insulin/IGF-1 signaling in the fruit fly Drosophila melanogaster. In invertebrates, multiple insulin-like ligands exist that bind to a common single insulin/IGF-1 like receptor. In contrast, in mammals, different receptors exist that bind insulin, IGF-1 and IGF-2 with different affinities. In several mouse models, mutations that are associated with decreased GH/IGF-1 signaling or decreased insulin signaling have been associated with enhanced lifespan. However, the increased complexity of the mammalian insulin/IGF-1 system has made it difficult to separate the roles of insulin, GH and IGF-1 in mammalian longevity. Likewise, the relevance of reduced insulin and IGF-1 signaling in human longevity remains controversial. However, studies on the genetic and metabolic characteristics that are associated with healthy longevity and old age survival suggest that the conserved ancient IIS pathway may also play a role in human longevity.

Hsieh CC et al. (2002) Mech Ageing Dev "Implications for the insulin signaling pathway in Snell dwarf mouse longevity: a similarity with the C. elegans longevity paradigm."

Papaconstantinou J, Hsieh CC, DeFord JH, Harrison DE, Flurkey K

[

Mech Ageing Dev,

2002]

Mutation analyses in the nematode, Caenorhabditis elegans, and mice have identified genes that increase their life-span via hormonal signal transduction, i.e. the insulin/insulin-like growth factor-1 (IGF-1) pathway in nematodes, and the growth hormone (GH)-thyriod stimulating hormone (TSH)-prolactin system in Snell dwarf mouse mutants. We have shown that the GH deficiency due to Pit1 mutation in the long-lived Snell dwarf mice may decrease circulating insulin levels, thereby resulting in a decreased activity of the insulin/IGF-1 signaling pathway. The data presented are consistent with our hypothesis that the decreased circulating insulin levels resulting from the Pit1 mutation mimics a physiological state similar to that proposed to occur in the long-lived C. elegans, daf-2 mutant. Our studies demonstrate a series of changes in components of the insulin/IGF-1-signaling pathway that suggest a reduction-of-function of this pathway in the aged dwarf. These include a decreased IRS-2 pool level, a decrease in PI3K activity and its association with IRS-2 and decreased docking of p85alpha to IRS-2. Our data also suggest a preferential docking of IRS-2-p85alpha-p110alpha in the aged dwarf liver and IRS-2-p85alpha-p110beta in the aged control. We speculate that the preference for the p110alpha-containing complex may be a specific characteristic of a downstream segment of the longevity-signaling cascade. We conclude that the Pit1 mutation may result in physiological homeostasis that favors longevity, and that the Snell dwarf mutant conforms to the nematode longevity paradigm.

Marques AR et al. (2003) Biochem J "Sphingomonas paucimobilis beta-glucosidase Bgl1: a member of a new bacterial subfamily in glycoside hydrolase family 1."

Coutinho PM, Marques AR, Videira P, Sa-Correia I, Fialho AM

[

Biochem J,

2003]

The Sphingomonas paucimobilis beta-glucosidase Bgl1 is encoded by the bgl1 gene, associated with an 1308 bp open reading frame. The deduced protein has a potential signal peptide of 24 amino acids in the N-terminal region, and experimental evidence is consistent with the processing and export of the Bgl1 protein through the inner membrane to the periplasmic space. A His(6)-tagged 44.3 kDa protein was over-produced in the cytosol of Escherichia coli from a recombinant plasmid, which contained the S. paucimobilis bgl1 gene lacking the region encoding the putative signal peptide. Mature beta-glucosidase Bgl1 is specific for aryl-beta-glucosides and has no apparent activity with oligosaccharides derived from cellulose hydrolysis and other saccharides. A structure-based alignment established structural relations between S. paucimobilis Bgl1 and other members of the glycoside hydrolase (GH) family 1 enzymes. At subsite -1, the conserved residues required for catalysis by GH1 enzymes are present in Bgl1 with only minor differences. Major differences are found at subsite +1, the aglycone binding site. This alignment seeded a sequence-based phylogenetic analysis of GH1 enzymes, revealing an absence of horizontal transfer between phyla. Bootstrap analysis supported the definition of subfamilies and revealed that Bgl1, the first characterized beta-glucosidase from the genus Sphingomonas, represents a very divergent bacterial subfamily, closer to archaeal subfamilies than to others of bacterial origin.

Coomansingh-Springer C et al. (2019) Heliyon "Internal parasitic burdens in brown rats (Rattus norvegicus) from Grenada, West Indies."

Sharma RN, Armstrong E, Vishakha V, Acuna AM, Coomansingh-Springer C

[

Heliyon,

2019]

This study identified the endoparasites in Brown rat (Rattus norvegicus) during May to July 2017 in Grenada, West Indies. A total of 162 rats, 76 females and 86 males were trapped from St. George and St. David parishes in Grenada. The collected fecal samples were examined for parasitic eggs and/or oocysts using simple fecal flotation technique. Adult parasites found in the intestinal tract were examined for identification. The overall prevalence of intestinal parasites among rats was 79 %. Ten helminth species were recovered, several of which were reported for the first time in rodents in Grenada. The internal parasites consist of seven nematodes (Angiostrongylus spp., Nippostrongylus braziliensis, Heterakis spumosa, Strongyloides ratti, Aspiculuris tetraptera, Syphacia spp. and Protospirura spp.), one cestode (Hymenolepsis diminuta), one acanthocephalan (Moniliformis moniliformis) and one protozoa species (Eimeria spp.). The most prevalent zoonotic species were Angiostrongylus spp. (35.2%), Hymenolepsis diminuta (7.4%) and Moniliformis moniliformis (3.1%). Several nonzoonotic endoparasites; which included Nippostrongylus braziliensis (50.6%), Heterakis spumosa (15.4%), Strongyloides ratti (43.2%), Aspiculuris tetraptera (2.5%), Syphacia spp. (1.9%), Protospirura spp. (1.2%) and Eimeria spp. (4.7%) were also identified. The most prevalent parasites were Nippostrongylus brasiliensis (50.6%), Strongyloides ratti (43.2%) and Angiostrongylus spp. (35.2%). Co-infections occurred with up to six species per rat showing different combinations of parasitic infections.