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Cryo Letters,
2013]
Cryopreservation of nematode Caenorhabditis elegans in the adult stage is of importance as the nematode is a powerful research model organism. In this study, we applied the protocol previously established for cryopreservation of the L4 nematode to the adult one, and achieved a survival rate of 84%. When ice seeding was induced with bacteria P. syringae directly added to the nematode suspension instead of using a pre-cooled steel sticking needle, comparable survival rate was obtained after thawing. Moreover, a simple freezing device composed of a polystyrene foam box surrounded by a Dewar vessel put in a deep freezer was developed for a practical use. This simple method obtained a survival rate of 69 +/- 4% for the adult nematode after thawing.
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J Nematol,
1970]
The effects of electric shock on Panagrellus redivivus adults and larvae and Meloidogyne incognita acrita larvae were studied. The nematodes were placed in tap water between two stainless steel electrodes, spaced 2 mm apart and cemented to a glass slide. Electric potentials of 1, 5, 10, 15, 20, 30, and 60 vdc/mm and vac/mm were applied for periods of 1 sec to 5 rain at 0.05 to 77 ma. The results demonstrated that ac or dc electric shocks as low as 5 v/mm for larvae and 10 v/mm for adults can be lethal. Some larvae and eggs within the body of P. redivivus females were not affected at 600 v/ram. Potentials of 20 and 60 vdc/mm for 2-sec stimulated hatch of Meloidogyne eggs.
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Biomater Sci,
2019]
Biomaterial-associated infections caused by bacterial contamination and the subsequent formation of biofilms on the surfaces are challenges faced by our healthcare system. In this work, povidone-iodine-functionalized fluorinated copolymers with stable antibacterial, antibiofilm, and antifouling activities were designed and prepared by a two-step synthesis. First, a series of poly(hexafluorobutyl methacrylate-co-N-vinyl-2-pyrrolidone), i.e., P(HFBMA-NVP), were synthesized by radical copolymerization at different feed ratios to acquire water insoluble and antifouling copolymers. At the second step, the NVP segments in the copolymer were complexed with iodine to obtain the objective antibacterial and antifouling copolymer P(HFBMA-NVP)-I. The chemical and physical characteristics of the copolymers were investigated using 1H NMR, FTIR, XPS, EDX, UV-Vis, SEM, TEM, elemental analysis, and contact angle measurement. P(HFBMA-NVP)-I exhibited excellent antibacterial activity against both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus), as well as good biocompatibility towards human hepatocyte cells (L02) and Caenorhabditis elegans. Using the electrospinning or spraying technique, P(HFBMA-NVP)-I was coated on polystyrene slides, medical stainless steel sheets, and cotton fabric, allowing the surfaces to have stable antibacterial and antibiofilm activities against pathogenic bacteria and antifouling capability against foulants and blood, and exhibit excellent self-cleaning properties.
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Exp Gerontol,
1975]
A technique is described for the continuous growth of an age-synchronized population of Caenrohabditis elegans. After initial isolation of newly hatched individuals from a mixed age culture, synchrony through the reproductive phase was sufficiently well maintained to ensure that over 90% of the post-reproductive population belonged to the original generation. The technique is based on culturing the nematodes on the upper surface of a fine stainless steel mesh through which only larvae, but not adults, are small enough to burrow. It largely overcomes serious disadvantages of the two previously used methods for maintaining synchrony which were based on the use of inhibitors or the manipulation of individual worms. Supplementary techniques are described for the handling and initial synchronization of the worms which are cultured in a sterile completely defined medium. General features of the development and senescence of the worms under our conditions are reported. Mean life span (50% survival) was approx. 58 days and maximum longevity in excess of 80 days. Reproduction lasted from the 5th to about the 26th day of age and its termination coincided with a short period of high mortality. Growth in size of the worms ceased during the reproductive period but recommenced for about 25 days in worms surviving the post-reproductive mortality.
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Pathog Dis,
2016]
The current study was intentionally focused on cyclo(L-leucyl- L-prolyl) (CLP)-a cyclic dipeptide with myriad pharmaceutical significance, to explore its antivirulence efficacy against the predominant food-borne pathogen-Listeria monocytogenes (LM). Minimum inhibitory concentration (MIC) of CLP against LM ATCC 19111 was found to be 512 g mL(-1). CLP at sub-MICs (64,128, 256 g mL(-1)) demonstrated a profound non-bactericidal dose-dependent antibiofilm efficacy (on polystyrene and glass) against LM, which was further confirmed through confocal and scanning electron microscopic analysis (on stainless steel surface). In vitro bioassays divulged the phenomenal inhibitory efficacy of CLP towards various virulence traits of LM, specifically its overwhelming suppression of swimming and swarming motility. Data of in vivo assay using Caenorhabditis elegans signified that the plausible mechanism of CLP could be by impeding the pathogen's initial adhesion and thereby attenuating the biofilm assemblage and its associated virulence. This was further confirmed by significant decrease in exopolymeric substance, auto-aggregation, hydrophobicity index and extracellular DNA (eDNA) of the CLP treated-LM cells. Collectively, the current study unveils the antivirulence efficacy of CLP against the Gram-positive food borne-pathogen and the strain Bacillus amyloliquifaciens augurs well to be a promising probiotic in controlling infections associated with LM.
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Toscanesi M, Tommasi F, Oral R, Mozzillo M, Gravina M, D'Ambra L, Siciliano A, Pagano G, Trifuoggi M, Thomas PJ, Lyons DM, Palumbo A, Crisci A, Guida M, Buric P
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Environ Monit Assess,
2018]
Adverse environmental conditions in the Taranto area (southern Italy) were investigated in studies of air, marine sediment, and human health. The present study aimed at providing unprecedented information on soil pollution and toxicity in a set of sites around recognized pollution sources in the Taranto area, since previous studies were focused on marine or air pollution, or on human health effects. The investigated area included a steel foundry and a power plant, as well as some sites located in an adjacent neighborhood. Surface soil samples and urban dust were collected and submitted to inorganic and organic analyses and tested for toxicity in two invertebrate bioassay models; a sea urchin (Sphaerechinus granularis) and an annelid (Caenorhabditis elegans). Inorganic analysis was carried out using ICP-MS for elemental composition for a total of 34 elements, whose levels were evaluated as a function of bioassay data analyzed through principal component analysis (PCA). Other analyses included asbestos search by powder X-ray diffraction (PXRD) and organic analysis for polycyclic aromatic hydrocarbons (PAHs) and aliphatic compounds (C10-C40). Toxicity bioassays were carried out on a sea urchin (Sphaerechinus granularis), and an annelid (Caenorhabditis elegans). Sea urchin bioassays evaluated effects of topsoil or street dust sample exposures (0.1 to 0.5% dry wt/vol) on developing embryos and on sperm, and scored as (a) % developmental defects, (b) inhibition of fertilization success and offspring damage, and (c) frequencies of mitotic aberrations. C. elegans mortality assay displayed significant toxicity associated with soil samples. The overall effects of samples showed very high toxicity at four out of nine sites. These effects were consistent with the highest levels measured for metals and PAHs. Further studies of health effects related to dust exposures in residential areas are warranted. Graphical abstract .
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Neurotoxicology,
2012]
Manganese (Mn) is a well established neurotoxin associated with specific damage to the basal ganglia in humans. The phenotype associated with Mn neurotoxicity was first described in two workers with occupational exposure to Mn oxide (Couper, 1837). Although the description did not use modern clinical terminology, a parkinsonian illness characterized by slowness of movement (bradykinesia), masked facies, and gait impairment (postural instability) appears to have predominated. Nearly 100 years later an outbreak of an atypical parkinsonian illness in a Chilean Mn mine provided a phenotypic description of a fulminant neurologic disorder with parkinsonism, dystonia, and neuropsychiatric symptoms (Rodier, 1955). Exposures associated with this syndrome were massive and an order of magnitude greater than modern exposures (Rodier, 1955; Hobson et al., 2011). The clinical syndrome associated with Mn neurotoxicity has been called manganism. Modern exposures to Mn occur primarily through occupations in the steel industry and welding. These exposures are often chronic and varied, occurring over decades in the healthy workforce. Although the severe neurologic disorder described by Rodier and Couper are no longer seen, several reports have suggested a possible increased risk of neurotoxicity in these workers (Racette et al., 2005b; Bowler et al., 2007; Harris et al., 2011). Based upon limited prior imaging and pathologic investigations into the pathophysiology of neurotoxicity in Mn exposed workers (Huang et al., 2003), many investigators have concluded that the syndrome spares the dopamine system distinguishing manganism from Parkinson disease (PD), the most common cause of parkinsonism in the general population, and a disease with characteristic degenerative changes in the dopaminergic system (Jankovic, 2005). The purpose of this symposium was to highlight recent advances in the understanding of the pathophysiology of Mn associated neurotoxicity from Caenorhabditis elegans to humans. Dr. Aschner's presentation discussed mechanisms of dopaminergic neuronal toxicity in C. elegans and demonstrates a compelling potential role of Mn in dopaminergic degeneration. Dr. Guilarte's experimental, non-human primate model of Mn neurotoxicity suggests that Mn decreases dopamine release in the brain without loss of neuronal integrity markers, including dopamine. Dr. Racette's presentation demonstrates a unique pattern of dopaminergic dysfunction in active welders with chronic exposure to Mn containing welding fumes. Finally, Dr. Dydak presented novel magnetic resonance (MR) spectroscopy data in Mn exposed smelter workers and demonstrated abnormalities in the thalamus and frontal cortex for those workers. This symposium provided some converging evidence of the potential neurotoxic impact of Mn on the dopaminergic system and challenged existing paradigms on the pathophysiology of Mn in the central nervous system.