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[
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi,
1999]
AIM: To study the allelic zymogram of periodic B. malayi from Zhejiang Province. METHODS: 180 adult worms(male 60, female 120), 32,000 microfilaria and 1,500 infective larvae of periodic B. malayi were examined for the isoenzymes of 14 enzymes by horizontal starch gel electrophoresis with 14 different isomyme. RESULTS: Twenty-seven allelic loci were found in three developing stages of B. malayi, most of them were homozygotes, however, two of them(MPI,MDH) were heterozygotes(7.4%). 17, 19 and 9 loci were presented in adult worms, microfilariae and infective larvae, respectively. At the same time, the allelic zymogram of B. malayi from Guizhou Province was also examined. CONCLUSION: The allelic zymogram of periodic B. malayi from Zhejiang Province was similar to that of periodic B. malayi from Guizhou Province but passaged in the laboratory.
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[
J Biol Chem,
2007]
The biological methyl donor, S adenosylmethionine (AdoMet), can exist in two diastereoisomeric states with respect to its sulfonium ion. The "S" configuration, (S,S)AdoMet, is the only form that is produced enzymatically as well as the only form used in almost all biological methylation reactions. Under physiological conditions, however, the sulfonium ion can spontaneously racemize to the "R" form, producing (R,S)AdoMet. As of yet, (R,S)AdoMet has no known physiological function and may inhibit cellular reactions. In this study, two enzymes have been found in Saccharomyces cerevisiae that are capable of recognizing (R,S)AdoMet and using it to methylate homocysteine to form methionine. These enzymes are the products of the SAM4 and MHT1 genes, previously identified as homocysteine methyltransferases dependent upon AdoMet and S-methylmethionine respectively. We find here that Sam4 recognizes both (S,S) and (R,S)AdoMet, but its activity is much higher with the R,S form. Mht1 reacts with only the R,S form of AdoMet while no activity is seen with the S,S form. R,S-specific homocysteine methyltransferase activity is also shown here to occur in extracts of Arabidopsis thaliana, Drosophila melanogaster, and Caenorhabditis elegans, but has not been detected in several tissue extracts of Mus musculus. Such activity may function to prevent the accumulation of (R,S)AdoMet in these organisms.
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Lou Y, Haque A, Freyzon Y, Farese RV, Terry-Kantor E, Hofbauer HF, Termine D, Welte MA, Barrasa MI, Imberdis T, Noble T, Lindquist S, Clish CB, Jaenisch R, Pincus D, Nuber S, Sandoe J, Kohlwein SD, Kim TE, Ho GPH, Ramalingam N, Walther TC, Baru V, Selkoe D, Srinivasan S, Landgraf D, Soldner F, Dettmer U, Fanning S, Becuwe M, Newby G
[
Mol Cell,
2018]
In Parkinson's disease (PD), -synuclein (S) pathologically impacts the brain, a highly lipid-rich organ. We investigated how alterations in S or lipid/fattyacid homeostasis affect each other. Lipidomic profiling of human S-expressing yeast revealed increases in oleic acid (OA, 18:1), diglycerides, and triglycerides. These findings were recapitulated in rodent and human neuronal models of S dyshomeostasis (overexpression; patient-derived triplication or E46K mutation; E46K mice). Preventing lipid droplet formation or augmenting OA increased S yeast toxicity; suppressing the OA-generating enzyme stearoyl-CoA-desaturase (SCD) was protective. Genetic or pharmacological SCD inhibition ameliorated toxicity in S-overexpressing rat neurons. In a C.elegans model, SCD knockout prevented S-induced dopaminergic degeneration. Conversely, we observed detrimental effects of OA on S homeostasis: in human neural cells, excess OA caused S inclusion formation, which was reversed by SCD inhibition. Thus, monounsaturated fatty acid metabolism is pivotal for S-induced neurotoxicity, and inhibiting SCD represents a novel PD therapeutic approach.
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[
PLoS One,
2017]
In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other's behavior, but additional studies are required necessary to elucidate the exact mechanism(s) involved.
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[
Small GTPases,
2019]
During development of the brain, neuronal circuits are formed through the projection of axons and dendrites in response to guidance signals. Rho GTPases (Rac1/RhoA/Cdc42) are major regulators of axo-dendritic outgrowth and guidance due to their role in controlling actin cytoskeletal dynamics, cell adhesion and motility. Functional redundancy of Rho GTPase-regulated pathways in neuronal development can mask the roles of specific GTPases. To examine potential Rho GTPase redundancy, we utilized a recently isolated hypomorphic mutation in a Caenorhabditis elegans Rac1 protein - CED-10(G30E) - which reduces the GTP binding and inhibits axon outgrowth of the PVQ interneurons. Here, we show that the CDC-42-specific guanine nucleotide exchange factor UIG-1 acts in parallel to CED-10/Rac1 to control PVQ axon outgrowth. UIG-1 performs this function in a cell-autonomous manner. Further, we found that transgenic expression of CDC-42 can compensate for aberrant CED-10(G30E)-regulated signalling during PVQ axon outgrowth. Together, our study reveals a previously unappreciated function for CDC-42 in PVQ axon outgrowth in C. elegans.
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[
Pathog Dis,
2014]
Due to the resistance of Staphylococcus aureus to several antibiotics, treatment of S. aureus infections is often difficult. As an alternative to conventional antibiotics, the field of bacterial interference is investigated. Staphylococcus epidermidis produces a serine protease (Esp) which inhibits S. aureus biofilm formation and which degrades S. aureus biofilms. In this study, we investigated the protease production of 114 S. epidermidis isolates, obtained from biofilms on endotracheal tubes (ET). Most of the S. epidermidis isolates secreted a mixture of serine, cysteine and metalloproteases. We found a link between high protease production by S. epidermidis and the absence of S. aureus in ET biofilms obtained from the same patient. Treating S. aureus biofilms with the supernatant (SN) of the most active protease producing S. epidermidis isolates resulted in a significant biomass decrease compared to untreated controls, while the number of metabolically active cells was not affected. The effect on the biofilm biomass was mainly due to serine proteases. Staphylococcus aureus biofilms treated with the SN of protease producing S. epidermidis were thinner with almost no extracellular matrix. An increased survival of Caenorhabditis elegans, infected with S. aureus Mu50, was observed when the SN of protease positive S. epidermidis was added.
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[
MicroPubl Biol,
2021]
From the beginning of Caenorhabditis elegans inception as a genetic model organism by Sydney Brenner (Brenner 1974), the ability to measure and quantify behavior in these nematodes led to numerous and powerful insights (Apfeld et al. 2018). The experimental amenability of worms makes them not just superb research subjects but also useful pedagogical tools. While excellent classroom additions to illustrate many biological processes, the educational potential of worms has lagged due to the expensive equipment required for their study. In most educational settings, lack of equipment discourages individual exploration and falls short of the promise owed to young and driven students. One of the places where this is felt strongly is in the automated quantification of animal behavior. Many systems have been developed over the years (and are currently used across the world) for the rapid and unbiased quantification of behavioral phenotypes. For example, we used tracking systems to compare the ability of mutant C. elegans strains to transition between gaits (Vidal-Gadea et al., 2011), and Deng and colleagues used them to study the role of inhibitory GABAergic motorneurons during rapid locomotion (Deng et al., 2020, see Husson et al. 2012 for a review of the use of tracking systems in C. elegans). Until recently, the automated quantification of C. elegans behavior was only feasible in specialized labs. Recent advances have begun to reduce the expense and complexity of automatically quantifying animal behavior. For example, the Haspel lab at NJIT made use of the recently developed Tierpsy behavioral software (Avelino et al. 2018) to build numerous animal tracking systems that are user friendly, and able to achieve levels of kinematic analysis that previously required considerably more expensive setups (Deng et al. 2020).
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Haass C, Hegermann J, Giese A, Eimer S, Kamp F, Lutz AK, Nuscher B, Wender N, Brunner B, Winklhofer KF, Exner N, Beyer K, Bartels T
[
EMBO J,
2010]
Aggregation of -synuclein (S) is involved in the pathogenesis of Parkinson's disease (PD) and a variety of related neurodegenerative disorders. The physiological function of S is largely unknown. We demonstrate with in vitro vesicle fusion experiments that S has an inhibitory function on membrane fusion. Upon increased expression in cultured cells and in Caenorhabditis elegans, S binds to mitochondria and leads to mitochondrial fragmentation. In C. elegans age-dependent fragmentation of mitochondria is enhanced and shifted to an earlier time point upon expression of exogenous S. In contrast, siRNA-mediated downregulation of S results in elongated mitochondria in cell culture. S can act independently of mitochondrial fusion and fission proteins in shifting the dynamic morphologic equilibrium of mitochondria towards reduced fusion. Upon cellular fusion, S prevents fusion of differently labelled mitochondrial populations. Thus, S inhibits fusion due to its unique membrane interaction. Finally, mitochondrial fragmentation induced by expression of S is rescued by coexpression of PINK1, parkin or DJ-1 but not the PD-associated mutations PINK1 G309D and parkin 1-79 or by DJ-1 C106A.
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[
Mol Cell Biol,
1997]
The cDNAs and genes encoding the intron lariat-debranching enzyme were isolated from the nematode Caenorhabditis elegans and the fission yeast Schizosaccharomyces pombe based on their homology with the Saccharomyces cerevisiae gene. The cDNAs were shown to be functional in an interspecific complementation experiment; they can complement an S. cerevisiae
dbr1 null mutant. About 2.5% of budding yeast S. cerevisiae genes have introns, and the accumulation of excised introns in a
dbr1 null mutant has little effect on cell growth. In contrast, many S. pombe genes contain introns, and often multiple introns per gene, so that S. pombe is estimated to contain approximately 40 times as many introns as S. cerevisiae. The S. pombe
dbr1 gene was disrupted and shown to be nonessential. Like the S. cerevisiae mutant, the S. pombe null mutant accumulated introns to high levels, indicating that intron lariat debranching represents a rate-limiting step in intron degradation in both species. Unlike the S. cerevisiae mutant, the S. pombe
dbr1::
leu1+ mutant had a severe growth defect and exhibited an aberrant elongated cell shape in addition to an intron accumulation phenotype. The growth defect of the S. pombe
dbr1::
leu1+ strain suggests that debranching activity is critical for efficient intron RNA degradation and that blocking this pathway interferes with cell growth.
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[
Am J Trop Med Hyg,
1988]
A comprehensive study of the transmission of Onchocerca volvulus at 4 locations in Guatemala with different prevalence rates of onchocerciasis included observations on potential secondary vectors, the most prevalent of which were Simulium metallicum, S. callidum, and S. gonzalezi. Filariae encountered in S. metallicum were primarily of a Dipetalonema-like species, but third-stage larvae indistinguishable from O. volvulus were found in 4 flies of this species. Our findings suggest that O. volvulus may occasionally be transmitted by S. metallicum, but such transmission is likely limited to areas having both a high parasite prevalence maintained by S. ochraceum and a relatively high host-seeking density of S. metallicum. Two third-stage larvae that could not be differentiated from O. volvulus were found once in S. gonzalezi; however, transmission by this species appears to be inconsequential.