Worm Life Research Articles

The alg-1 Gene Is Necessary for Orsay Virus Replication in Caenorhabditis elegans.

The establishment of the Orsay virus-Caenorhabditis elegans infection model has enabled the identification of host factors essential for virus infection. Argonautes are RNA interacting proteins evolutionary conserved in the three domains of life that are key components of small RNA pathways. C. elegans encodes 27 argonautes or argonaute-like proteins. Here, we determined that mutation of the argonaute-like gene 1, alg-1, results in a greater than 10,000-fold reduction in Orsay viral RNA levels, which could be rescued by ectopic expression of alg-1. Mutation in ain-1, a known interactor of ALG-1 and component of the RNA-induced silencing complex, also resulted in a significant reduction in Orsay virus levels. Viral RNA replication from an endogenous transgene replicon system was impaired by the lack of ALG-1, suggesting that ALG-1 plays a role during the replication stage of the virus life cycle. Orsay virus RNA levels were unaffected by mutations in the ALG-1 RNase H-like motif that ablate the slicer activity of ALG-1. These findings demonstrate a novel function of ALG-1 in promoting Orsay virus replication in C. elegans. IMPORTANCE All viruses are obligate intracellular parasites that recruit the cellular machinery of the host they infect to support their own proliferation. We used Caenorhabditis elegans and its only known infecting virus, Orsay virus, to identify host proteins relevant for virus infection. We determined that ALG-1, a protein previously known to be important in influencing worm life span and the expression levels of thousands of genes, is required for Orsay virus infection of C. elegans. This is a new function attributed to ALG-1 that was not recognized before. In humans, it has been shown that AGO2, a close relative protein to ALG-1, is essential for hepatitis C virus replication. This demonstrates that through evolution from worms to humans, some proteins have maintained similar functions, and consequently, this suggests that studying virus infection in a simple worm model has the potential to provide novel insights into strategies used by viruses to proliferate.

Salmonella Typhimurium infection causes defects and fastening of Caenorhabditis elegans developmental stages

Salmonella infection is known to cause a 50% reduction in the lifespan of Caenorhabditis elegans. But the mechanism behind this reduction is not reported. The current study deals with the Salmonella infection mediated egg retention in the worm leading to various developmental and morphological defects and disruption of temporal regulation of developmental timing in C. elegans. Worm’s delayed egg-laying response to Salmonella infection causes several defects in eggs, including over-folding of developing embryo, increased egg size, and losing the osmotic stress resistance. Also, the infected eggs show delayed and reduced hatching. With significantly downregulated lin-28a, col-72 and col-87, we observed a disrupted L2, but L3, L4, and adult developmental stages reach faster during infection. The precocious development of L3, L4, and the adult stage is further indicated by upregulation of stage-specific genes viz. rnh-1.3, col-158 and col-176 (L3), col-17, col-38 and col-49 (L4), and col-19, col-7 (adult). The significant upregulation of the flp-1 gene indicates reduced egglaying, and the flp-1(ok2811) null mutant further supported the Salmonella infectionmediated phenotype. Similar phenotypes are primarily evident in multiple generations up to F5 and F6. Salmonella infection causes a range of developmental anomalies and shortening of worm life span through various regulatory pathways.

GENE EXPRESSION LEVEL, IMMUNOLOCALIZATION, AND FUNCTION OF FATTY ACID-BINDING PROTEIN FROM SCHISTOSOMA JAPONICUM.

The Schistosoma japonicum fatty acid-binding protein (FABP) is used in the cell membrane to absorb and transport fatty acids, which cannot be resynthesized by the organism and combined with hydrophobic ligands. Among the 5 stages of the worm life cycle examined, FABP messenger ribonucleic acid (mRNA) expression was highest in male adult worms, followed by the liver-stage schistosome, and was the lowest in the lung-stage schistosome. The fabp gene-coding region was cloned and expressed to obtain recombinant S. japonicum FABP (rSjFABP) with a molecular weight of approximately 18 kDa. Mice were then immunized against rSjFABP to prepare anti-FABP serum. Using immunohistochemical techniques, FABP protein was found to localize to the eggshell, parenchyma, and digestive tract. Double-stranded RNA-mediated knockdown of FABP mRNA by RNA interference decreased the number of transcripts by >70%. Moreover, the egg production rate decreased, whereas the abnormal egg ratio was significantly increased in the FABP-silenced group compared with the negative control group (P < 0.05). These results demonstrate that FABP localizes in adults and in various stages. FABP contributes to the egg-laying capacity of adults, which may be related to the reproductive function of S. japonicum.

Comparative Analysis of Proteins of Functionally Different Body Parts of the Fish Parasites Triaenophorus nodulosus and Triaenophorus crassus.

Studies of proteins expressed in the morphological structures of the parasite are necessary for elucidating the biological functions of unknown proteins and understanding the molecular basis of parasitism. The research aim was to investigate the spatial distribution of major proteins in scolex, immature and gravid proglottids of Triaenophorus nodulosus and Triaenophorus crassus. Protein extracts of worm body parts were analyzed using two-dimensional difference gel electrophoresis (DIGE) and mass spectrometry. Comparison of the protein repertoire of the adult worm and the encysted plerocercoid revealed differences between the worm body parts, life stages and parasite species. The content of proteins associated with the cytoskeleton and musculature (actin, myosin regulatory light chain, and tropomyosin 2) decreased with distance from the scolex. Mature proglottids were rich in transforming growth factor-beta-induced protein, propionyl-CoA carboxylase, glutamate dehydrogenase and beta-tubulin. Interspecific variation in T. nodulosus and T. crassus was found in the content of the myosin, paramyosin, the major vault protein and an uncharacterized secreted protein TRINITY_DN24645. Differential expression of TRINITY_DN24645, paramyosin and tropomyosin 2 was found between plerocercoids and adult worms. The present study provides the first characteristics of the spatial distribution of the major proteins of T. crassus and T. nodulosus. Comparison of the protein composition of plerocercoids and adult parasites indicates a significant similarity in the proteomic organization of Triaenophorus sp. in the second intermediate and final hosts. The gradual change in the morphological organization of tapeworms in the longitudinal direction coincided with the expression of some structural and metabolic proteins.

Influence of external environmental factors on the productivity of mulberry silkworm (Bombyx mori L) in different sizes of silk breeding organizations

The information presented in this article suggests that the larger the silkworm breeding organization (SBO), the harder it is to maintain a comfortable temperature, relative humidity, and other environmental factors, resulting in the development of silkworm cocoons. differently, the process of implementing agro-technical measures is disrupted. As a result, industrial cocoons are reported to have a yield of 14-17%, viability 22-25%, worm life 7-9 days and silkworm cocoons 7-13%.

Preparation of Wood Ear Mushroom, Auricularia auricula-judae (Agaricomycetes), Polysaccharides by Neutral Protease and Their Antioxidant Stress Capacity.

Response surface methodology with a Box-Behnken design was used to investigate the effects of a neutral protease on Auricularia auricula-judae polysaccharide (AAP) extraction yield. Four ethanol concentrations (30%, 50%, 70%, and 90%) were used to grade AAPs. Optimal fractions with a high polysaccharide recovery rate and a strong free radical scavenging rate were obtained, and their antioxidant stress effect was studied using Caenorhabditis elegans as the model organism. The results showed that among the factors affecting AAP yield (temperature, liquid-to-A. auricula-judae powder, enzyme usage, time, pH, etc.), temperature, ratio of liquid-to-A. auricula-judae powder, and time had the most obvious effects. AAP yield reached 13.91% ± 0.95% at a temperature of 7°C, liquid-to-material ratio of 75 mL/g, and extraction time of 70 min. High AAP recovery rates and strong free radical scavenging rates of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt and 1,1-dibenzoyl-2-trinitrophenylhydrazine were obtained by 30% ethanol (AAPs1). Results from the anti-hydrogen peroxide and methyl viologen stress experiment showed that AAPsl could significantly prolong the life of worms under oxidative stress compared to the negative control group (P < 0.05).

DAF-16 acts as the "hub" of astaxanthin's anti-aging mechanism to improve aging-related physiological functions in Caenorhabditis elegans.

Astaxanthin (AX) is a xanthophyll carotenoid that can effectively inhibit the production of peroxides and thereby protect the body from oxidative damage. In recent years, AX had been shown to have anti-aging properties, both in vivo and in vitro. However, the underlying mechanisms by which AX regulates senescence related proteins and signaling pathways remain unclear. Therefore, we used Caenorhabditis elegans (C. elegans) model binding proteomics to reveal AX anti-aging activity and its molecular mechanism. Our results suggest that AX promotes the health and lifespan of C. elegans by improving mobility, reducing the accumulation of age pigments, and increasing resistance to heat stress. In terms of the underlying mechanism, AX helps prolong the life of worms by regulating AGE-1 in the insulin signaling pathway, promoting the transport of DAF-16 into the nucleus and then up-regulating the expression level of DAF-16's downstream proteins (such as superoxide dismutase [Mn] 2 (SOD-3), heat shock proteins (HSPs), glutathione s-transferase (GST-4), etc.). Furthermore, AX may be a relevant response target for activation of dietary restriction pathways in vivo as a dietary restriction mimic. Meanwhile, proteomics data confirmed that there were 15 proteins enriched in the longevity regulation pathway. AX mainly regulates oxidative stress and the aging process by modulating the insulin signaling pathway around DAF-16 as the "hub". In addition to the insulin signaling pathway, other pathways including dietary restriction, AMP-activated protein kinase (AMPK), and mammal target of rapamycin (mTOR) are also dependent on DAF-16. These findings expand and deepen our knowledge of the underlying mechanism by which AX extends the lifespan of C. elegans.

The risks of shell‐boring polychaetes to shellfish aquaculture in Washington, USA: A mini‐review to inform mitigation actions

In 2017, Polydora websteri, a shell-boring spionid polychaete worm and cosmopolitan invader, was identified for the first time in Washington State. Shell-boring Polydora spp. and related shell-boring spionid polychaetes (e.g., Dipolydora spp., Boccardia spp.), colloquially known as mud worms or mud blister worms, live in burrows within the shells of calcareous marine invertebrates, reducing the host's shell integrity, growth, survivorship and market value. Mud worms have a long history of impacting shellfish aquaculture industries worldwide by devaluing products destined for the half-shell market and requiring burdensome treatments and interventions to manage against infestation. Here, we explore the risks of mud worms to the historically unaffected aquaculture industry in Washington State. This mini-review is intended to inform shellfish stakeholders by synthesizing the information needed for immediate action in Washington State. We review the recent documentation of Polydora spp. in Washington State, discuss their history as pest species globally, summarize mud worm life history, and discuss effective control strategies developed in other infested regions. Finally, we review existing regulations that could be leveraged by stakeholders to avoid introduction of mud worms into uninfested areas of Washington State.

Increased REST to Optimize Life Span?

Reduced levels of neural activity are associated with a longer life span in the nematode Caenorhabditis elegans and in mice. Augmented neural activity is associated with a shorter life span. Recent studies show that levels of repressor element 1-silencing transcription factor (REST) increase with normal aging in mice and humans, and reduce neuronal excitation. In C. elegans, increased expression of spr-4, a functional REST homologue, increased the worm life span and is required for classical life span increase mediated by reduced DAF-2/insulin-IGF-1 and increased DAF-16. Preliminary evidence shows that REST and FOXO1, a DAF-16, homologue increase during mammalian aging, and that REST activity is needed for the age-related FOXO1 increase. On the contrary, REST is activated in epilepsy and plays a role in the pathogenesis of Huntington's disease. A simple unifying hypothesis suggests that REST is a "goldilocks-effect factor": too little REST promotes excitotoxic activity, which in turn leads to neurodegenerative diseases such as Alzheimer's. Appropriate increased levels of REST maintain the excitation/inhibition (E-I) balance by reducing potential excitotoxic activity. Increased levels of REST beyond this are toxic as neurons become dysfunctional due to loss of a neuronal phenotype.

Aiweixin, a Traditional Uyghur Medicinal Formula, Extends the Lifespan of Caenorhabditis elegans.

Aiweixin (AWX) is a traditional Uyghur medicine prescription, which has been used to treat senile diseases for a long time. We investigate whether the AWX extends the lifespan of Caenorhabditis elegans. The AWX decoction was the conventional product for clinical use. The wild-type Caenorhabditis elegans (N2) and mutational worms, daf-16(mu86), glp-1(e2141), daf-2(e1370), and eat-2(ad465), were applied for the lifespan analysis. We found that the lifespan of the N2 adults' worm received 0.005 and 0.01 volume of AWX/total volume was extended significantly, compared to the control without treatment of AWX. The AWX at 0.01 volume of AWX/total volume significantly prolonged the life of both mutational worms, daf-16 (mu86) and eat-2(ad465), but did not increase the lifespan of the mutational worms, daf-2(e1370) and glp-1(e2141). These results indicated that the AWX significantly extended the lifespan of wild-type nematodes, and the life extension effect of AWX was related to the germline longevity pathway and IIS signaling pathway but independent of DAF-16/FOXO.

Inappropriateness of RNAlater to preserve Caenorhabditis elegans for RNA extraction

Caenorhabditis elegans is a well-established laboratory animal model and has been widely used in biological research. However, it is still a challenge to obtain a good amount of quality RNA from a limited number of C. elegans for gene expression studies. To address this issue, the present study has compared different conditions to preserve C. elegans for RNA extraction after the failure of an initial effort to use RNAlater-preserved worms for RNA extraction. The effects of different concentrations of proteinase K, different worm life stages, and different worm numbers on RNA extraction were also investigated. The best results were achieved under the following conditions: 1) adult worms that were either freshly prepared or quickly frozen in liquid nitrogen followed by storage at −80 °C; 2) disruption of C. elegans with proteinase K (1 mg/mL) in a lysis buffer (65 °C for 10 min) prior to extraction with Trizol agent. This method can provide a stable, rapid, and effective means to extract RNA from C. elegans with variable worm numbers from 20 to 200.•RNAlater was inappropriate for preserving C. elegans for effective RNA extraction.•Proteinase K was verified for lysing a limited number of C. elegans for RNA extraction.

ANALISIS PENDAPATAN USAHA BUDIDAYA CACING SUTERA DENGAN MEDIA NAMPAN BERTINGKAT ; KASUS USAHA KELUARGA DI DESA KARANGTEJO KEDU TEMANGGUNG JAWA TENGAH DAN UJI COBA DI BELITANG OKU TIMUR

This research aims to know the techniques of cultivation and silk worm life terms with the media tray multilevel. To calculate the income level of the silk worm cultivation efforts with media in the village-floor tray Karangtejo Kedu Temanggung Central Java as well as key factors for the development of silk worm in Belitang OKU East. Data processing methods used are of financial analysis (cost of production, production, reception, income and RC ratio) and non financial analysis (Bahaninput, Agroklimat, potential market). The research results obtained with silk worm cultivation media tray multilevel can be dikebangkan in the East viewed from the OKU Belitang market potential is great with silk worms requests in one month about 2815 glasses. The available input materials among others, silk worm seed dregs of tofu, chicken manure, fine bran. Temperature suitability trials with cultivation in Eastern silk worm Belitang OKU can adapt and expand the container trays. Production costs incurred in one fell prosesproduksi amounting to Rp 9,256,350, Rp gained acceptance 18,977,000 and revenue amounting to Rp 9,720,650 with a value of RC ratio of 2.05.

Pharynx mitochondrial [Ca2+] dynamics in live C. elegans worms during aging.

Progressive decline in mitochondrial function is generally considered one of the hallmarks of aging. We have expressed a Ca2+ sensor in the mitochondrial matrix of C. elegans pharynx cells and we have measured for the first time mitochondrial [Ca2+] ([Ca2+]M) dynamics in the pharynx of live C. elegans worms during aging. Our results show that worms stimulated with serotonin display a pharynx [Ca2+]M oscillatory kinetics that includes both high frequency oscillations (up to about 1Hz) and very prolonged “square-wave” [Ca2+]M increases, indicative of energy depletion of the pharynx cells. Mitochondrial [Ca2+] is therefore able to follow “beat-to-beat” the fast oscillations of cytosolic [Ca2+]. The fast [Ca2+]M oscillations kept steady frequency values during the whole worm life, from 2 to 12 days old, but the height and width of the peaks was progressively reduced. [Ca2+]M oscillations were also present with similar kinetics in respiratory chain complex I nuo-6 mutant worms, although with smaller height and frequency than in the controls, and larger width. In summary, Ca2+ fluxes in and out of the mitochondria are relatively well preserved during the C. elegans life, but there is a clear progressive decrease in their magnitude during aging. Moreover, mitochondrial Ca2+ fluxes were smaller in nuo-6 mutants with respect to the controls at every age and decreased similarly during aging.

A sensitive mass spectrometry platform identifies metabolic changes of life history traits in C. elegans

Abnormal nutrient metabolism is a hallmark of aging, and the underlying genetic and nutritional framework is rapidly being uncovered, particularly using C. elegans as a model. However, the direct metabolic consequences of perturbations in life history of C. elegans remain to be clarified. Based on recent advances in the metabolomics field, we optimized and validated a sensitive mass spectrometry (MS) platform for identification of major metabolite classes in worms and applied it to study age and diet related changes. Using this platform that allowed detection of over 600 metabolites in a sample of 2500 worms, we observed marked changes in fatty acids, amino acids and phospholipids during worm life history, which were independent from the germ-line. Worms underwent a striking shift in lipid metabolism after early adulthood that was at least partly controlled by the metabolic regulator AAK-2/AMPK. Most amino acids peaked during development, except aspartic acid and glycine, which accumulated in aged worms. Dietary intervention also influenced worm metabolite profiles and the regulation was highly specific depending on the metabolite class. Altogether, these MS-based methods are powerful tools to perform worm metabolomics for aging and metabolism-oriented studies.

Study on the tolerance and adaptation of rats to Angiostrongylus cantonensis infection.

Angiostrongylus cantonensis (A. cantonensis) is the most common infectious agent causing eosinophilic meningitis. As an important food-borne parasitic disease, angiostrongyliasis cantonensis is an emerging infectious disease which brings severe harm to central nerve system of human. Rat, one of the few permissive hosts of A. cantonensis known to date, plays an indispensable role in the worm's life cycle. However, the tolerance and adaptation of rat to A. cantonensis infection is rarely understood. In this study, we infected rats with different numbers the third stage larvae (L3) of A. cantonensis and explored their tolerance through analysis on survival curve, neurological function score, and detection of pathological damages in organs including the brain, lung, and heart of the animals. Results indicated that rats' survival condition worsens, and body weight dropped more significantly as more worms were used for infection. Death appeared in groups infected with 80 and more A. cantonesnsis per rat. Morris water maze revealed that the neurological function of rats damaged gradually with increasing infection number of A. cantonensis larvae. When the number of infected parasite exceeded 240 per animal, rats showed significant neurological impairments. Collection of A. cantonensis from rat lung after 35days of infection implied an upper limit for worm entry, and the average length of worm was inversely proportional to the infection amount, while the ratio between female and male worms was positively related to the infection number. The degree of pulmonary and cardiac inflammation was proportional to the infection number of A. cantonensis. Meanwhile, there existed considerable amount of adult worms in rat's right atrium and right ventricle, leading to a right heart myocardial inflammation. The present study firstly reports the tolerance and adaptation of rat, a permissive host of A. cantonensis to its infection, which will not only provide accurate technical parameters for maintaining A. cantonensis life cycle under laboratory conditions but also help unveil the underlying mechanism of the distinct pathological outcomes in the permissive and non-permissive hosts with A. cantonensis infection.

Investigating the Underlying Mechanisms of Chemosensory Dysfunctions in Alzheimer's Disease Using Caenorhabditis elegans with Mutations in Presenilin 1

BackgroundMany cases of familial Alzheimer's disease (FAD) are linked to mutations of the presenilin (PS) genes. These genes are orthologous with sel‐12 genes in Caenorhabditis elegans, a transparent roundworm. C.elegans have a small nervous system consisting of 302 neurons, making it an ideal candidate for system‐level genetic analysis of neural circuits and behavior. Olfactory dysfunction is an early symptom of AD. However, the underlying mechanisms of these dementia‐linked deficits are unknown.MethodsChemotaxis experiments were conducted on worms with a mutation in sel‐12 to gain a better understanding of the relationship between presenilin 1 (PS1) mutations in AD and olfactory deficits. To understand this phenomenon further, we examined various stages of the worm's life cycle to determine when this deficit appeared. This provided preliminary insight into the dynamics of PS1 mutations and its subsequent effect on cellular pathways involved in chemosensation. Since C. elegans are innately repulsed by the odorant octanol and attracted by the odorant diacetyl, we utilized these two odorants in chemotaxis assays to assess the olfactory function of sel‐12 mutants.ResultsAdult sel‐12 mutants had a significantly decreased sensitivity to octanol and diacetyl compared to wild‐type worms. Introducing human wild‐type PS1 into the nervous system of C. elegans rescued olfactory defects, while a PS1 mutant from Alzheimer's patients did not. Moreover, C. elegans sel‐12 mutants presented olfactory deficits from hatching, and this deficit increased as worms aged, similar to the neurodegenerative progression of AD.ConclusionsThis study demonstrates that mutations in C. elegans orthologue of PS1 are associated with altered chemosensation, and that these deficits were rescued by the wild‐type human PS gene in the nervous system.Future DirectionsIn order to localize the region(s) where wild‐type sel‐12 function is required for normal olfaction, sel‐12 and PS1 rescues will be conducted in specific neurons that are responsible for the detection of octanol and diacetyl. We will also investigate the morphology of these neurons and compare them to those of wild‐type worms.

Correspondence of D. melanogaster and C. elegans developmental stages revealed by alternative splicing characteristics of conserved exons

BackgroundWe report a statistical study to find correspondence of D. melanogaster and C. elegans developmental stages based on alternative splicing (AS) characteristics of conserved cassette exons using modENCODE RNA-seq data. We identify “stage-associated exons” to capture the AS characteristics of each stage and use these exons to map pairwise stages within and between the two species by an overlap test.ResultsWithin fly and worm, adjacent developmental stages are mapped to each other, i.e., a strong diagonal pattern is observed as expected, supporting the validity of our approach. Between fly and worm, two parallel mapping patterns are observed between fly early embryos to early larvae and worm life cycle, and between fly late larvae to adults and worm late embryos to adults. We also apply this approach to compare tissues and cells from fly and worm. Findings include the high similarity between fly/worm adults and fly/worm embryos, groupings of fly cell lines, and strong mappings of fly head tissues to worm late embryos and male adults. Gene ontology and KEGG enrichment analyses provide a detailed functional annotation of the identified stage-associated exons, as well as a functional explanation of the observed correspondence map between fly and worm developmental stages.ConclusionsOur results suggest that AS dynamics of the exon pairs that share similar DNA sequences are informative for finding transcriptomic similarity of biological samples. Our study is innovative in two aspects. First, to our knowledge, our study is the first comprehensive study of AS events in fly and worm developmental stages, tissues, and cells. AS events provide an alternative perspective of transcriptome dynamics, compared to gene expression events. Second, our results do not entirely rely on the information of orthologous genes. Interesting results are also observed for fly and worm cassette exon pairs with DNA sequence similarity but not in orthologous gene pairs.

Kendali Optimal Model Siklus Hidup Cacing Schistosoma japonicum dengan Prinsip Minimum Pontryagin

Schistosomiasis is an infectious disease caused by trematodes, of the genus Schistosoma. In Indonesia the disease is caused by Schistosoma japonicum. The worm life cycle is specific because its habitat is not only on human body or some other mammal but also in snail. This research is aimed to a mathematical model of the worm cycle and investigates the optimal control of the model. The mathematically control was conducted by put a time dependent parameter ρ (t) to the model that represents a medical treatment to infected humans. The governed model, that has an endemic stable critical point, describes a transferred worm cycle of several phases. The optimal control is determined by the Minimum Pontryagin Principle. The simulation of the model shows that, for such initial condition of the uncontrolled model, the number of adult worms will increase up to 4700 in 80 days. This number could reduce to 4500 on the day of 100 and converge to 4400for unbounded time growth. It means that schistosomiasis is permanently occurring (endemic). The controlled model gives as the drug dose of praziquantel. The drug doze of 20 mg praziquantel could minimize the growth of worms and decreasethe number of adult worm population to 8 in 6 months.

Fluorescence-Based Screening Assays for the NAD+-Dependent Histone Deacetylase smSirt2 from Schistosoma mansoni

Sirtuins are NAD+-dependent histone deacetylases (HDACs) that cleave off acetyl but also other acyl groups from the ϵ-amino group of lysines in histones and other substrate proteins. Five sirtuin isoforms are encoded in the genome of the parasitic pathogen Schistosoma mansoni. During its life cycle, S. mansoni undergoes drastic changes in phenotype that are associated with epigenetic modifications. Previous work showed strong effects of hSirt2 inhibitors on both worm life span and reproduction. Thus, we postulate smSirt2 as a new antiparasite target. We report both the optimization of a homogeneous fluorescence-based assay and the development of a new heterogeneous fluorescence-based assay to determine smSirt2 activity. The homogeneous assay uses a coumarin-labeled acetyl lysine derivative, and the heterogeneous version is using a biotinylated and fluorescence-labeled oligopeptide. Magnetic streptavidin-coated beads allow higher substrate loading per well than streptavidin-coated microtiter plates and make it possible to screen for inhibitors of either smSirt2 or its human isoform (hSirt2) for selectivity studies. We also present hits from a pilot screen with inhibitors showing an IC50 lower than 50 µM. Binding of the hits to their targets is rationalized by docking studies using a homology model of smSirt2.

Cytoskeleton protects from stress and aging

Aging The transcription factor HSF-1 has an unexpected second function that allows it to extend longevity in worms. Baird et al. expressed a modified form of HSF-1 in nematodes. The modified protein could not activate genes encoding protein chaperones. Such chaperones are thought to protect many cellular proteins from heat shock and other damage during aging However, the modified protein still extended the worm life span by regulating the transcription of other genes. One gene it regulated was pat-10 , which encodes a troponin-like calcium binding protein. Overexpression of PAT-10 also extended worm life span, apparently by changing the stability of the actin cytoskeleton. Science , this issue p. [360][1] [1]: /lookup/doi/10.1126/science.1253168