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1.
K. Moebus 《Helgoland Marine Research》1992,46(3):275-292
Between April 3 and September 24, 1991, the concentrations of bacteriophages infecting bacterial strains, isolated in 1990
and during this investigations, were determined in 35 samples of seawater taken at station ‘Kabeltonne’ adjacent to Helgoland.
Similar to the findings of 1990, phage concentrations of several hundred plaque forming units (PFU) ml−1 were observed with a number of indicator strains, the maximum concentration being at least 1.5×103 PFU ml−1. These high concentrations lasted for only a few days, generally decreasing at rates between 0.6 and 0.9 day−1. Phage concentrations of 0 to 2 PFU ml−1 were found to be predominant until the end of June, occasionally attaining 5 PFU ml−1. From July through September, when high phage concentrations were observed with some indicator strains, between 0 and 10
PFU ml−1 were found in the majority of tests. As revealed by a final phage-host cross-reaction test, the greater part of 138 indicator
bacteria is genetically related, and almost half of the 200 phage strains tested are propagated only by their original indicator
bacterium. The possible importance of mutational events for the maintenance of phage-host systems in nature is discussed. 相似文献
2.
The distributions of bacterial populations in sea ice and underlying seawater were investigated on the continental shelf of
the “Terre Adélie” area. A reference station was sampled weekly from January 1991 to January 1992. In winter, the survey included
a minimum of six sampling layers: surface and bottom ice, brine, seawater from the interface, and at 0.5 and 2 m depth. In
seawater, the total bacterial abundance ranged from 0.5 × 105 cells ml−1 in July to 6.0 × 105 cells ml−1 after ice break. Values reaching 2.5 × 106 cells ml−1 were recorded in the overlying ice cover. Mean cell volumes were twice as high in brine as in seawater. The saprophytic bacterial
abundance ranged from 5.0 × 104 CFU (colony-forming units) ml−1 in some winter interface samples to less than 1.0 × 103 CFU ml−1 in most of the summer seawater samples. In sea ice a clear decreasing gradient for most of the studied bacterial parameters
from the surface layers towards the bottom layer was found. The ice cover had a discernible impact on underlying seawater,
but its influence was restricted to a limited interface layer. 相似文献
3.
Viruses play a significant role in nutrient cycling within the world’s oceans and are important agents of horizontal gene
transfer, but little is know about their entrainment into sea ice or their temporal dynamics once entrained. Nilas, grease
ice, pancake ice, first-year sea ice floes up to 78 cm in thickness, and under-ice seawater were sampled widely across Amundsen
Gulf (ca. 71° N, 125° W71^\circ \hbox{N}, 125^\circ \hbox{W}) for concentrations of viruses and bacteria. Here, we report exceptionally high virus-to-bacteria ratios in seawater (45–340)
and sea ice (93–2,820) during the autumn freeze-up. Virus concentrations ranged from 4.8 to 27 × 106 ml−1 in seawater and, scaled to brine volume, 5.5 to 170 × 107 ml−1 in sea ice. Large enrichment indices indicated processes of active entrainment from source seawater, or viral production
within the ice, which was observed in 2 of 3 bottle incubations of sea ice brine at a temperature (-7°C-7^\circ\hbox{C}) and salinity (
110 \permille110 \permille) approximating that in situ. Median predicted virus-to-bacteria contact rates (relative to underlying seawater) were greatest
in the top of thick sea ice (66–78 cm: 130×) and lowest in the bottom of medium-thickness ice (33–37 cm: 23×). The great abundance
of viruses and more frequent interactions between bacteria and viruses predicted in sea ice relative to underlying seawater
suggest that sea ice may be a hot spot for virally mediated horizontal gene transfer in the polar marine environment. 相似文献
4.
Dynamics of cyanophage-like particles and algicidal bacteria causing Microcystis aeruginosa mortality 总被引:1,自引:0,他引:1
The dynamics of cyanophage-like particles and algicidal bacteria that infect the bloom-forming cyanobacterium Microcystis aeruginosa was followed in a hyper-eutrophic pond from September 1998 to August 1999. The densities of M. aeruginosa ranged between 4.0 × 105 and 1.9 × 107 cells ml−1, whereas those of algicidal bacteria were between 4.0 and 5.1 × 102 plaque-forming units (PFU) ml−1 and those of cyanophage-like particles were between <5.0 × 102 and 7.1 × 103 PFU ml−1. A significant relationship was found between the densities of algicidal bacteria and M. aeruginosa (r = 0.81, n = 69, P < 0.001), suggesting that the dynamics of the algicidal bacteria may regulate the abundance of M. aeruginosa. Occasional peaks of density of cyanophage-like particles were detected in October, June, and August, when sharp declines
in M. aeruginosa cell densities were also observed. The densities of cyanophage-like particles became undetectable when the abundance of M. aeruginosa was low, suggesting the density-dependent infection of M. aeruginosa by cyanophage-like particles. Thus, we suggest that infections of both algicidal bacteria and cyanophage-like particles are
important biological agents that decompose blooms of M. aeruginosa in freshwater environments.
Received: August 31, 2000 / Accepted: December 6, 2000 相似文献
5.
Park YJ Lee JY Yeom HR Kim KH Lee SC Shim IK Chung CP Lee SJ 《Biotechnology letters》2005,27(22):1761-1766
Injectable polysaccharide microcapsules holding minocycline were fabricated from alginate and chitosan for the treatment of
periodontitis. The microcapsules were examined for the release and degradation of minocycline, as well as antimicrobial activity.
The microcapsules were biodegradable and released minocycline between 10 and 1000 μg ml−1, which was higher than the usual therapeutic concentration (1–5 μg ml−1), for up to 7 days. These microcapsules showed a statistically significant suppression of pathogenic bacteria, such as Prevotella intermedia causing periodontitis. The microcapsules are thus potentially useful for drug delivery for the treatment of periodontitis. 相似文献
6.
Jeff Kneebone Darren E. Ferguson James A. Sulikowski Paul C. W. Tsang 《Environmental Biology of Fishes》2007,80(2-3):257-265
The smooth skate, Malacoraja senta, and thorny skate, Amblyraja radiata, are two commercially exploited batoids found within the Gulf of Maine. During the past five years, we conducted a large
study to accurately describe important biological life history parameters previously lacking for these species. As part of
that project, the current study reports our findings on the hormonal profiles associated with the reproductive cycles of M. senta and A. radiata. Blood samples were obtained from mature M. senta and A. radiata of both sexes from all months of the year, and plasma testosterone (T), estradiol (E2) and progesterone (P4) concentrations were determined using radioimmunoassay (RIA). In female M. senta and A. radiata, monthly T concentrations ranged from 4,522 pg ml−1 to 1,373 pg ml−1 and 31,940 pg ml−1 to 14,428 pg ml−1, E2 concentrations from 831 pg ml−1 to 60 pg ml−1 and 8,515 pg ml−1 to 2,902 pg ml−1, and P4 concentrations from 3,027 pg ml−1 to 20 pg ml−1 and 3,264 pg ml−1 to 331 pg ml−1, respectively. No statistical differences were detected between any months for any hormone. Estradiol concentrations were
not correlated with ovary weight, shell gland weight, or diameter of the largest follicles in either species. Monthly T concentrations
in male M. senta and A. radiata ranged from 23,146 to 12,660 pg ml−1 and from 57,500pg ml−1 to 24,737 pg ml−1, while E2 concentrations ranged from 7.5 pg ml−1 to undetectable and 103 to 30 pg ml−1, respectively. No statistical differences were observed between months for either steroid. Testosterone concentrations were
weakly correlated with testes weight and percent of stage VI spermatocysts in A. radiata, however, no correlation was detected between T and stage VI spermatocysts in M. senta. Collectively, these data support the previous conclusion that M. senta and A. radiata of both sexes are capable of reproducing year round in the western Gulf of Maine. 相似文献
7.
Arthrospira
platensis SAG 21.99 and the isolated bacteria (Halomonas spp., Staphylococcus sp., etc.) from the culture of A. platensis SAG 21.99 were treated with five antibiotics to determine the minimal lethal concentrations. The combination of a washing
step and a consecutive treatment with antibiotics, imipenem (100 μg ml−1), neomycin (100 μg ml−1) and cycloheximide (20 μg ml−1), treatment step was highly effective in eliminating bacteria. An axenic culture of A. platensis SAG 21.99 could be induced within 3 days using this method. This technique is a simple and rapid method for obtaining axenic
cultures of filamentous cyanobacteria. 相似文献
8.
The effect of several plant growth regulators on the number of tumors developing on potato tuber discs (Solatium tuberosum L. cv. Radka) inoculated withAgrobacterium tumefaciens, strain C 58 was studied. The plant growth regulators used in appropriate range of concentrations stimulated the formation
of tumors byA. tumefaciens.
Naphthaleneacetic acid (NAA) was most active in concentration of 10−4 mg ml−1. Kinetin gave a biphasic response with optimal promotions of tumor initiation at 10−4 − 2 × 10−3 mg ml−1. High kinetin concentration (10−1 mg ml−1) inhibited the formation of tumors completely. Indoleacetic acid (IAA) stimulated the initiation of tumors in the same range
of concentrations as kinetin, except that very high concentrations did not inhibit but enhanced tumor formation. 2,4-diehlorphenoxyacetic
acid (2,4-D) showed a biphasic response with maxima in 10−4 mg ml−1 and 10−1 mg ml−1. All the tumors scored for nopaline production showed nopaline synthase activity independently whether their formation was
stimulated by l0−1 mg ml−1 IAA or they were initiated without any treatment by plant growth regulators. 相似文献
9.
The use of clove oil as a potential anaesthetic for freshwater amphipods was examined at 20 °C. Individuals of Gammarus minus, a common species in southern Illinois, USA, spanning the entire body size range (4.3–14.3 mm), were used to test four anaesthetic
concentrations varying from 1.48 × 10−4 ml ml−1 to 5.9 × 10−4 ml ml−1. Small-bodied individuals (mean size = 5.4 mm ± 0.27SE) were used to test additional concentrations, up to 14.7 × 10−4 ml ml−1, a 10-fold span, to identify potential lethal concentrations. At the lowest concentration, time to anaesthesia and recovery
was constant at all body sizes. For the three next higher concentrations, time to anaesthesia decreased with increasing concentration
while recovery time increased. Activity of amphipods was not affected by the ethanol carrier. In addition, activity did not
differ between amphipods that had recovered from anaesthesia and unexposed amphipods. At clove oil concentrations of 8.84
× 10−4 ml ml−1 and 14.7 × 10−4 ml ml−1, mortality was 7 and 40%, respectively, indicating, that 5.9 × 10−4 ml ml−1 was a safe working concentration. No mortality was observed with Gammarus acherondytes, a federally endangered cave amphipod on which the protocol with 80 μl of stock was used in the field. The method enabled
us to obtain information on the endangered amphipod which normally would have required the sacrifice of individuals. Thus,
research can continue on species for which population numbers are low and for which basic information is needed to formulate
meaningful recovery plans. 相似文献
10.
Ciliate and bacterial densities and their link with eutrophication were studied in fourteen shallow lakes in northwest Spain.
Total phosphorus (TP) in these lakes varied between 30 μg l−1 and 925 μg l−1 and chlorophyll a concentration (chla) between 0.5 μg l−1 and 107 μg l−1. Bacterial abundance ranged from 1 × 106 to 14 × 106 cells ml−1, while ciliate abundance ranged from 0.6 cells ml−1 to 229 cells ml−1. Lakes were classified into three trophic types from their TP and chla concentrations. Bacterial abundance was significantly
correlated with trophic type, as well as with TP and with chla separately, whereas ciliate abundance was only correlated with
chla. No significant relationship could be established between bacterial and ciliate abundance across the trophic gradient.
A general pattern was observed in the ratios of bacterial abundance to TP and chla concentrations, of decreasing ratios with
increases in the nutrient loading. This pattern was not found for ciliates. The dominant zooplankton group in 13 of the 14
lakes studied was Rotifera, which accounted for a mean of 71% of total zooplankton abundance (41% of zooplankton biomass).
The positive correlation between bacteria and ciliates with this group, and the absence of any relationship with Cladocera
suggest that top down control by cladocerans was weaker in our lakes than previously shown in northern European shallow lakes.
Rotifers could be important predators of bacteria in the high-nutrient lakes of our study. Higher slopes of regressions on
bacterial abundance towards the hypertrophic range indicate that top-down control was weaker in our lakes than in northern
European shallow lakes. 相似文献
11.
In this study, the effects of inositol addition on expression of the MAL gene encoding maltase and phosphatidylinositol (PI) biosynthesis in Schizosaccharomyces pombe (a naturally inositol-requiring strain) were examined. We found that specific maltase activity was at its maximum when the concentration of added inositol reached 6 μg ml−1 in a synthetic medium containing 2.0% (w/v) glucose. When the concentration of added inositol was 1 μg ml−1 in the medium, repression of MAL gene expression occurred at glucose concentration higher than 0.2% (w/v). However, when S. pombe was cultured in the synthetic medium containing 6 μg ml−1, repression of maltase gene expression occurred only at initial glucose concentration above 1.0% (w/v). More mRNA encoding maltase was detected in the cells grown in the medium with 6 μg ml−1 inositol than in those grown in the same medium with 1 μg ml−1 inositol. These results demonstrate that higher inositol concentrations in the synthetic medium could derepress MAL gene expression in S. pombe. PI content of the yeast cells grown in the synthetic medium with 6 μg ml−1 of inositol was higher than that of the yeast cells grown in the same medium with 1 μg ml−1 of inositol. This means that PI may be involved in the derepression of MAL gene expression in S. pombe. 相似文献
12.
Mustafa Çelik Fatma Ünal Deniz Yüzbaşıoğlu Serkan Yılmaz Hüseyin Aksoy Şengül Karaman 《Cytotechnology》2006,51(2):99-104
In this investigation, clastogenic effects of Thymus kotschyanus var. glabrescens Boiss. extract (TE) and anticlastogenic effects of this extract against Mitomycin C (MMC) induced chromosome damage have been evaluated in human peripheral blood lymphocytes in vitro. Two series of experiments were conducted. In the first, only 10−5, 10−4, 10−3 and 10−2 μl ml−1 concentrations of TE were used for 48 h to detect potential clastogenicity. In the second, MMC (0.38 μg ml−1) plus 10−5, 10−4, 10−3 and 10−2 μl ml−1 concentrations of TE were used for 48 h to determine anticlastogenic effects. TE did not increase sister chromatid exchanges (SCEs) (except 10−2 μl ml concentration) and chromosome aberrations (CAs) significantly compared with negative and solvent controls. However, it decreased the frequency of MMC induced chromosome aberrations. Decreasing was significant at 10−4, 10−3 and 10−2 μl ml−1 concentrations. On the other hand, TE significantly increased MMC-induced SCEs for all treatment groups compared with positive control. 相似文献
13.
Novel Antifoulants: Inhibition of Larval Attachment by Proteases 总被引:3,自引:0,他引:3
We investigated the effect of commercially available enzymes (α-amylase, α-galactosidase, papain, trypsin, and lipase) as
well as proteases from deep-sea bacteria on the larval attachment of the bryozoan Bugula neritina L. The 50% effective concentrations (EC50) of the commercial proteases were 10 times lower than those of other enzymes. Crude proteases from six deep-sea Pseudoalteromonas species significantly decreased larval attachment at concentrations of 0.03 to 1 mIU ml−1. The EC50 of the pure protease from the bacterium Pseudoalteromonas issachenkonii UST041101-043 was close to 1 ng ml−1 (0.1 mIU ml−1). The protease and trypsin individually incorporated in a water-soluble paint matrix inhibited biofouling in a field experiment.
There are certain correlations between production of proteases by bacterial films and inhibition of larval attachment. None
of the bacteria with biofilms that induced attachment of B. neritina produced proteolytic enzymes, whereas most of the bacteria that formed inhibitive biofilms produced proteases. Our investigation
demonstrated the potential use of proteolytic enzymes for antifouling defense. 相似文献
14.
D. A. Gray S. K. Maloney 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(8):558-562
The relationship between body temperature (T
b) and the plasma concentrations of arginine vasotocin (AVT) and angiotensin II (AII) was examined in conscious, adult Pekin
ducks. Exposure of birds to an ambient temperature of 40 °C for 3 h increased T
b by about 1.5 °C and increased breathing rate five-fold. Plasma osmolality was elevated from the normothermic value of 294.9 ± 1.4
mosmol kg−1 by about 8 mosmol kg−1 Circulating AVT levels increased by about 2 pg ml−1 from a basal concentration of 4.98 ± 0.15 pg ml−1, a rise which could be accounted for by the change in osmotic status. Plasma AII concentrations were unchanged from the pre-heat
exposure value of 31.8 ± 3.4 pg ml−1. Time control birds, exposed only to an ambient temperature of 22 °C demonstrated no significant changes in any of the measured
variables. The results suggest that an increased T
b has no direct effect on the circulating concentrations of AVT or AII in ducks.
Accepted: 2 June 1997 相似文献
15.
We evaluated the combined effects of algal (Chlorella vulgaris) food levels (low, 0.5 × 106 (or 2.9 μg C ml−1); and high, 1 × 106 cells ml−1 (or 5.8 μg C ml−1)) and zinc concentrations (0, 0.125, and 0.250 mg l−1 of ZnCl2) on the competition between two common planktonic rotifers Anuraeopsis fissa and Brachionus rubens using their population growth. Median lethal concentration data (LC50) (mean ± 95% confidence intervals) showed that B. rubens was more resistant to zinc (0.554 ± 0.08 mg l−1) than A. fissa (0.315 ± 0.07 mg l−1). A. fissa when grown alone or with Zn was always numerically more abundant than B. rubens. When grown in the absence of zinc, under low- and high-food levels, the peak abundances of A. fissa varied from 251 ± 24 to 661 ± 77 ind. ml−1, respectively, and the corresponding maxima for B. rubens were 52 ± 3 and 102 ± 18 ind. ml−1. At a given food level, competition for food reduced the peak abundances of both rotifers considerably. Increase in Zn concentration
also lowered the rotifer abundances. The impact of zinc on competition between the two-rotifer species was evident at low-food
level, mainly for A. fissa. At zinc concentrations of 0 and 0.125 mg l−1, the populations of both rotifers continued to grow for about 10 days, but thereafter B. rubens began to decline. Role of zinc on the competitive outcome of the two species is discussed in relation to the changing algal
densities in natural water bodies. 相似文献
16.
Candida cylindracea NRRL Y-17506 was grown to produce extracellular lipase from oleic acid as a carbon source. Through flask cultures, it was found that the optimum initial oleic acid concentration for cell growth was 20 g l−1. However, high initial concentrations of oleic acid up to 50 g l−1 were not inhibitory. The highest extracellular lipase activity obtained in flask culture was 3.0 U ml−1 after 48 h with 5 g l−1 of initial oleic acid concentration. Fed-batch cultures (intermittent and stepwise feeding) were carried out to improve cell concentration and lipase activity. For the intermittent feeding fed-batch culture, the final cell concentration was 52 g l−1 and the extracellular lipase activity was 6.3 U ml−1 at 138.5 h. Stepwise feeding fed-batch cultures were carried out to simulate an exponential feeding and to investigate the effects of specific growth rate (0.02, 0.04 and 0.08 h−1) on cell growth and lipase production. The highest final cell concentration obtained was 90 g l−1 when the set point of specific growth rate (μset) was 0.02 h−1. High specific growth rate (0.04 and 0.08 h−1) decreased extracellular lipase production in the later part of fed-batch cultures due to build-up of the oleic acid oversupplied. The highest extracellular lipase activity was 23.7 U ml−1 when μset was 0.02 h−1, while the highest lipase productivity was 0.31 U ml−1 h−1 at μset of 0.08 h−1. 相似文献
17.
In this study, using a bioassay-guided isolation and purification procedure, we obtained 3-chloro-2,5-dihydroxybenzyl alcohol
from a marine-derived Ampelomyces species that effectively inhibited larval settlement of the tubeworm Hydroides elegans and of cyprids of the barnacle Balanus amphitrite. The inhibitive effect on larval settlement was nontoxic and the EC50 of 3-chloro-2,5-dihydroxybenzyl alcohol ranged from 3.19 μg ml−1 to 3.81 μg ml−1 while the LC50 was 266.68 μg ml−1 for B. amphitrite cyprids; EC50 ranged from 0.67 μg ml−1 to 0.78 μg ml−1, and LC50 was 2.64 μg ml−1 for competent larvae of H. elegans, indicating that inhibitive effect of this compound was nontoxic. At a concentration of 50 μg per disc, this compound showed
strong inhibitive effects on the growth of 13 out of 15 marine bacterial species tested in disc diffusion bioassay. Overall,
the high inhibitory activities against bacteria and larval settlement as well as the non- or low-toxic nature of this compound
to the barnacle and polychaete larvae suggest this compound could be a potent antifoulant and/or antibiotic. 相似文献
18.
Teresa Manso Carla Nunes Sara Raposo Maria Emília Lima-Costa 《Journal of industrial microbiology & biotechnology》2010,37(11):1145-1155
Large-scale production has been the major obstacle to the success of many biopesticides. The spreading of microbial biocontrol
agents against postharvest disease, as a safe and environmentally friendly alternative to synthetic fungicides, is quite dependent
on their industrial mass production from low-cost raw materials. Considerable interest has been shown in using agricultural
waste products and by-products from food industry as nitrogen and carbon sources. In this work, carob pulp aqueous extracts
were used as carbon source in the production of the biocontrol agent Pantoea agglomerans PBC-1. Optimal sugar extraction was achieved at a solid/liquid ratio of 1:10 (w/v), at 25°C, for 1 h. Batch experiments were
performed in shake flasks, at different concentrations and in stirred reactors at two initial inoculums concentrations, 106 and 107 cfu ml−1. The initial sugar concentration of 5 g l−1 allowed rapid growth (0.16 h−1) and high biomass productivity (0.28 g l−1 h−1) and was chosen as the value for use in stirred reactor experiments. After 22 and 32 h of fermentation the viable population
reached was 3.2 × 109 and 6.2 × 109 cfu ml−1 in the fermenter inoculated at 106 cfu ml−1 and 2.7 × 109 and 6.7 × 109 cfu ml−1 in the bioreactor inoculated at 107 cfu ml−1. A 78% reduction of the pathogen incidence was achieved with PBC-1 at 1 × 108 cfu ml−1, grown in medium with carob extracts, on artificially wounded apples stored after 7 days at 25°C against P. expansum. 相似文献
19.
A Pseudomonas sp. strain NGK 1 (NCIM 5120) was immobilized in various matrices, namely, alginate, agar (1.8 × 1011 cfu g−1 beads) and polyacrylamide (1.6 × 1011 cfu g−1 beads). The degradation of naphthalene was studied, by freely suspended cells (4 × 1010 cfu ml−1) and immobilized cells in batches, with shaken culture and continuous degradation in a packed-bed reactor. Free cells brought
about the complete degradation of 25 mmol naphthalene after 3 days of incubation, whereas, a maximum of 30 mmol naphthalene
was degraded by the bacteria after 3–4 days of incubation with 50 mmol and 75 mmol naphthalene, and no further degradation
was observed even after 15 days of incubation. Alginate-entrapped cells had degraded 25 mmol naphthalene after 3.5 days of
incubation, whereas agar- and polyacrylamide-entrapped cells took 2.5 days; 50 mmol naphthalene was completely degraded by
the immobilized cells after 6–7 days of incubation. Maximum amounts of 55 mmol, 70 mmol and 67 mmol naphthalene were degraded,
from an initial 75 mmol naphthalene, by the alginate-, agar- and polyacrylamide-entrapped cells after 15 days of incubation.
When the cell concentrations were doubled, 25 mmol and 50 mmol naphthalene were degraded after 2 and 5.5 days of incubation
by the immobilized cells. Complete degradation of 75 mmol naphthalene occurred after 10 days incubation with agar- and polyacrylamide-entrapped␣cells,
whereas only 60 mmol naphthalene was degraded by alginate-entrapped cells after 15 days of␣incubation. Further, with 25 mmol
naphthalene, alginate-, agar- and polyacrylamide-entrapped cells (1.8 × 1011 cfu g−1 beads) could be reused 18, 12 and 23 times respectively. During continuous degradation in a packed-bed reactor, 80 mmol naphthalene
100 ml−1 h−1 was degraded by alginate- and polyacrylamide-entrapped cells whereas 80 mmol naphthalene 125 ml−1␣h−1 was degraded by agar-entrapped cells.
Received: 21 October 1997 / Received revision: 15 January 1998 / Accepted: 18 January 1998 相似文献
20.
The in vitro cytotoxicity of the antimicrobial peptide P40 was investigated. The food grade bacteriocin nisin was also analyzed
for comparison. VERO cells were treated with different concentrations (0.02–2.5 μg ml−1) of nisin and P40, and cell viability and plasma membrane integrity were checked by MTT, neutral red uptake (NRU), and lactate
dehydrogenase (LDH) assays. In MTT and NRU assays the EC50 to the purified peptide P40 were 0.30 and 0.51 μg ml−1, while values found to nisin were 0.35 and 0.79 μg ml−1, respectively. In the LDH assay, the EC50 was 0.57 and 0.62 μg ml−1 for P40 and nisin, respectively. The peptide P40 revealed higher hemolytical activity (19%) when compared to nisin (4.9%)
at the highest concentration tested (2.5 μg ml−1). Relatively few studies about the cytotoxicity of antimicrobial peptides are available. The determination of the cytotoxicity
of antimicrobial peptides is an essential step to warrant their safe use. 相似文献