Yuan P et al. (2018) Food Funct "Black tea increases hypertonic stress resistance in C. elegans."

Gong YS, Yuan P, Tong JW, Xiong LG, Huang JA, Pan LY, Li J, Liu ZH

[Food Funct, 2018]

Here we identified that BTE (black tea extract), within the studied concentration range, is more effective than GTE (green tea extract) in protecting C. elegans against hypertonic stress, by enhancing survival after exposure to various salts, and alleviating suffered motility loss and body shrinkage. The mechanism of such protection may be due to the ability of black tea to induce the conserved WNK/GCK signaling pathway and down-regulation of the expression levels of nlp-29. Intriguingly, black tea does not relieve hypertonicity-induced protein damage. The findings implicate the potential health benefits of black tea consumed worldwide.

Kow, Rebecca et al. (2021) International Worm Meeting "Loss of aly genes suppresses toxicity in transgenic Caenorhabditis elegans models of tau or TDP-43"

Kraemer, Brian, Saxton, Aleen, Black, Aristide, Kow, Rebecca

[International Worm Meeting, 2021]

Both the microtubule-associated protein tau and the DNA and RNA binding protein TDP-43 accumulate into toxic aggregates in multiple neurodegenerative diseases such as Alzheimer's disease and frontotemporal dementia. We have previously used transgenic Caenorhabditis elegans models of human tau and TDP-43 to discover novel genes that modulate their toxicity. These transgenic models are characterized by significant locomotor deficits, progressive loss of neurons, shortened lifespan, and accumulation of hyperphosphorylated and insoluble tau or TDP-43 protein. One gene identified as a strong suppressor of tau toxicity in C. elegans and mammalian models is the RNA binding protein sut-2/MSUT2/ZC3H14. To better understand the mechanism in which sut-2 suppresses tauopathy, we investigated the aly genes (3 genes in C. elegans), whose mammalian homolog ALYREF has been shown to interact with MSUT2/ZC3H14 (Morris & Corbett (2018) Nucleic Acids Res 46:6561-6575). Additionally, research in Drosophila melanogaster of TDP-43 toxicity showed that loss of the fly homolog ref1 could suppress TDP-43-induced toxicity (Berson et al (2019) Acta Neuropath Commun 7:65). Therefore we determined whether loss of aly genes suppressed tau and/or TDP-43 toxicity in our C. elegans models. We found that loss of aly-1 or aly-2 alone, but not aly-3, caused mild suppression of tau-induced locomotor deficits, while loss of aly-2 and aly-3 together caused the strongest suppression of locomotor deficits. Loss of aly-2 and aly-3 reduced total and insoluble tau protein accumulation as well as neuron loss with age in tau transgenic C. elegans. In TDP-43 transgenic C. elegans, loss of aly-2 and aly-3 also suppressed behavioral deficits induced by TDP-43 but did not significantly alter total TDP-43 or phosphorylated TDP-43 protein levels. The results here suggest that although the aly genes modulate both tau and TDP-43-induced toxicity, they do so via different mechanisms.

Ahier A et al. (2018) Nat Cell Biol "Publisher Correction: Affinity purification of cell-specific mitochondria from whole animals resolves patterns of genetic mosaicism."

Kirmes I, Tweedie A, Ahier A, Dai CY, Zuryn S, Bezawork-Geleta A

[Nat Cell Biol, 2018]

In the version of this Technical Report originally published, chromosome representations (indicated by black lines) were missing from Fig. 2a due to a technical error. The corrected version of Fig. 2a is shown below. This has now been amended in all online versions of the Technical Report.

Alhassan A et al. (2014) PLoS One "A simple isothermal DNA amplification method to screen black flies for Onchocerca volvulus infection."

Alhassan A, Osei-Atweneboana MY, Makepeace BL, Carlow CK, LaCourse EJ

[PLoS One, 2014]

Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a), to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP) assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis.

Lee K et al. (2014) Appl Microbiol Biotechnol "Anti-biofilm, anti-hemolysis, and anti-virulence activities of black pepper, cananga, myrrh oils, and nerolidol against Staphylococcus aureus."

Cho MH, Kim SI, Lee J, Lee JH, Lee K

[Appl Microbiol Biotechnol, 2014]

The long-term usage of antibiotics has resulted in the evolution of multidrug-resistant bacteria. Unlike antibiotics, anti-virulence approaches target bacterial virulence without affecting cell viability, which may be less prone to develop drug resistance. Staphylococcus aureus is a major human pathogen that produces diverse virulence factors, such as -toxin, which is hemolytic. Also, biofilm formation of S. aureus is one of the mechanisms of its drug resistance. In this study, anti-biofilm screening of 83 essential oils showed that black pepper, cananga, and myrrh oils and their common constituent cis-nerolidol at 0.01 % markedly inhibited S. aureus biofilm formation. Furthermore, the three essential oils and cis-nerolidol at below 0.005 % almost abolished the hemolytic activity of S. aureus. Transcriptional analyses showed that black pepper oil down-regulated the expressions of the -toxin gene (hla), the nuclease genes, and the regulatory genes. In addition, black pepper, cananga, and myrrh oils and cis-nerolidol attenuated S. aureus virulence in the nematode Caenorhabditis elegans. This study is one of the most extensive on anti-virulence screening using diverse essential oils and provides comprehensive data on the subject. This finding implies other beneficial effects of essential oils and suggests that black pepper, cananga, and myrrh oils have potential use as anti-virulence strategies against persistent S. aureus infections.

Jason R. Pfeiffer et al. (2007) International Worm Meeting "The Na+/H+ exchanger, nhx-2, influences lipid deposition and metabolic gene expression."

David Johnson, Keith Nehrke, Jason R. Pfeiffer

[International Worm Meeting, 2007]

RNAi-mediated knockdown of the intestinal Na&#43/H&#43 exchanger, nhx-2, leads to a complex phenotype, resulting in worms with an acidified intestinal intracellular pH (pHi) that develop slowly into small and clear adults. Our initial observations suggested that normal fat metabolism may require NHX-2 and we hypothesized that nhx-2(RNAi) acts as a caloric restriction mimetic. To further test this hypothesis, we stained lipid directly with Sudan Black in fixed worms and also with Nile Red by feeding. Knockdown of nhx-2 caused a loss of intestinal staining in both the Sudan Black stained and the Nile Red fed worms. The Sudan Black staining also revealed a marked expansion of hypodermal lipid droplets in nhx-2(RNAi) animals. The droplets appeared early during larval development and apparently occurred only at the anterior and posterior aspects of hyp7. Similar hypodermal lipid droplets have been described previously in insulin signaling mutants. To determine if this lipid droplet phenotype is also characteristic of dietary restriction (DR) we stained a common DR model, the eat-2(ad1113) mutant, with Sudan Black. The pattern of Sudan Black staining was essentially the same as that for N2 worms, suggesting that the nhx-2(RNAi) phenotype differs at least in this aspect from a well-established model of DR. In an effort to better understand the molecular aspects of the complex metabolic phenotype caused by nhx-2(RNAi), we performed semi-quantitative RT-PCR using a metabolic primer set directed at one-hundred and fifty target genes (courtesy of Dr. Mark van Gilst). The most profound and significant changes occurred in several transcripts coding for components of the fatty acid beta-oxidation pathways in both mitochondria and peroxisomes. We are currently generating reagents to examine cell-specific changes in metabolic gene expression in hyp7 and in the intestine, where the effects of nhx-2(RNAi) are apparently functionally dichotomous.

Higazi TB et al. (2011) Am J Trop Med Hyg "Polymerase chain reaction pool screening used to compare prevalence of infective black flies in two onchocerciasis foci in northern Sudan."

Hassan HK, Richards F, Mackenzie CD, Mohamed HA, Higazi TB, Unnasch TR, Deran TC, Aziz N, ElMubark WA, Mohamed WA, Zarroug IM, Katabarwa M

[Am J Trop Med Hyg, 2011]

Onchocerciasis remains an important debilitating disease in many areas of Africa, including Sudan. The status of infection transmission in 2007 was assessed in the vectors of two disease foci in Sudan: Abu Hamed in northern Sudan, which has received at least 10 years of annual treatment and Galabat focus in eastern Sudan, where only minor, largely undocumented treatment activity has occurred. Assessment of more than 30,000 black flies for Onchocerca volvulus infectious stage L3 larvae by using an O-150 polymerase chain reaction protocol showed that black fly infectivity rates were 0.84 (95% confidence interval = 0.0497-1.88) per 10,000 flies for Abu Hamed and 6.9 (95% confidence interval = 1.1-16.4) infective flies per 10,000 for Galabat. These results provide entomologic evidence for suppressed Onchocerca volvulus transmission in the Abu Hamed focus and a moderate transmission rate of the parasite in the Galabat focus.

Ishii K et al. (2001) Heredity "Sexual isolation and cuticular hydrocarbons in Drosophila elegans."

Hirai Y, Katagiri C, Kimura MT, Ishii K

[Heredity, 2001]

In Drosophila elegans, partial sexual isolation has developed between the brown and black morphs, which are distributed allopatrically. The present study aims to understand how they discriminate between potential mates. Mating experiments show that the females of the two morphs differ in sexual signal(s) and the males discriminate using these differences. Body colouration is not used as a sexual cue in this species. Between the females of the two morphs, a large difference was observed in the percentages of 7-pentacosene and 9-pentacosene on the cuticle. Genetical analysis using recombinant inbred lines supported the possibility that the concentration of these pentacosenes plays a role in mate discrimination of these two morphs. However, males did not respond to killed females at all, suggesting that cuticular hydrocarbons of females are not the only cue for the induction of male courtship behaviour. It may be that unknown signals or substances are essential to induce male courtship and pentacosenes modulate the attractiveness of females, positively in the black morph and negatively in the brown morph. Drosophila elegans F1 offspring had intermediate characteristics in mate discrimination and hydrocarbon composition between the parental brown and black morph strains. The number of loci responsible for the differences in the concentration of pentacosenes and the male and female components in the mate recognition between these two morphs is suggested to be more than one.

Trpis M et al. (1990) Am J Trop Med Hyg "Effect of mass treatment of a human population with ivermectin on transmission of Onchocerca volvulus by Simulium yahense in Liberia, West Africa."

Trpis M, Fryauff DJ, Munoz BE, Williams PN, Taylor HR, Childs JE, Greene BM, Pacque MC

[Am J Trop Med Hyg, 1990]

The impact of mass treatment with ivermectin on the intensity of Onchocerca volvulus transmission by the black fly (Simulium yahense) was evaluated on the Liberian Agricultural Company rubber plantation in Liberia, West Africa. The adult pre-treatment prevalence of onchocerciasis was greater than 80%, and the average intensity of infection was 5.35 mf/mg of skin. The drug was administered at 2 annual intervals, reaching 58-60% of the approximately 14,000 people living in 73 camps. Landing/biting catches of black flies made in central and peripheral plantation zones indicated similar fly activity before and after ivermectin treatment (man hr index of 2.1 and 2.4 within the plantation, and 10 and 10.9 outside the plantation, respectively). The number of infected flies with developing larvae (L1, L2, L3 stages) of O. volvulus in treated areas was reduced by 93.4-95%; the number of infective flies with L3 larvae was reduced by 81.7-89.3%. Parasite loads of infected (L1, L2) and infective flies (L3 stages only) outside the plantation also decreased by 86.8% and 80%, respectively. Monthly transmission potential (MTP) showed a similar decrease: from 22.9 to 5.8 (74.6% reduction) in the treated area, and from 210 to 158.8 (24.4% reduction) in untreated areas. Mass treatment with ivermectin efficiently controlled, and at least temporarily interrupted, transmission of Onchocerca volvulus by black fly vectors.

Mahapatra N et al. (1999) J Helminthol "Bacillus sphaericus interferes with the development of Brugia malayi in Aedes aegypti."

Hazra RK, Dash AP, Mahapatra N, Acharya AS, Rup S

[J Helminthol, 1999]

Aedes aegypti (black-eyed Liverpool strain) were exposed to a sublethal dose (LD25) of Bacillus sphaericus and were fed to Mastomys coucha infected with Brugia malayi. The development of the filarial parasite was found to be arrested mostly at the second larval stage. The infection (P < 0.05), infectivity rates (P < 0.001) and L3 load (P < 0.001) were found to be reduced significantly in the treated group.