Activity of a novel compound produced by Aspergillus parasiticus in the presence of red flour beetle Tribolium castaneum against Pseudomonas aeruginosa and coleopteran insects     

Elena Cartagena  Karenina Marcinkevicius  Constanza Luciardi  Germán Rodríguez  Alicia Bardón  Mario E. Arena 《Journal of pest science》2014,87(3):521-530

Aspergillus is a promising source of bioactive secondary metabolites. The addition of insect-derived material in the broth culture could trigger the biosynthesis of insecticidal and antimicrobial compounds by entomopathogenic fungus (EF). Insects inhabit diverse niches and interact with various bacteria, for this reason, when a fungus kills an insect should inhibit the insect’s gut bacteria to prevent the insect consumption by bacteria. According with this hypothesis, the EF is able to produce substances that inhibit bacteria growth or bacteria virulence strategies. In the present, investigation is demonstrated that the addition of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) components (2 % w/v) in a culture of saprophytic fungus Aspergillus parasiticus MOR 3 induces the production of a novel compound present inside mycelium 2-(4-bromophenyl)-2-oxoethyl benzoate, that is reported here for the first time as a natural product of A. parasiticus. In addition, increased significantly the fungal extracellular production of undecyl 4-fluorobenzoate. The mycelium extract (ME) at 250 μg per g of diet on adult population of T. castaneum produced an alteration of the feeding behavior of coleopteran insects (Repellency index = +30). The fraction derived from ME (Fr2) that contained the organobromine compound, 2-(4-bromophenyl)-2-oxoethyl benzoate had the highest inhibition of the Pseudomonas aeruginosa virulence factors like elastase enzyme (49 %) at 5 μg/ml and biofilm formation (43 %) at 100 μg/ml. The results suggest that the extract from mycelium of a non-aflatoxigenic A. parasiticus MOR 3 strain is a potential candidate as food coleopteran repellent as well as an anti-virulence strategy of P. aeruginosa.  相似文献   

Exploitation of bacterial pectinolytic strains for improvement of hemp water retting     

Elena Tamburini  Alicia Gordillo León  Brunella Perito  Mario Di Candilo  Giorgio Mastromei 《Euphytica》2004,140(1-2):47-54

Summary Retting is the major limitation to an efficient production of textile hemp fibres. Traditional retting has been carried out by autochthonous bacterial community. Aerobic and anaerobic pectinolytic strains were isolated from hemp or flax sources and characterised. Anaerobic pectinolytic strains had a wide range of acid polygalacturonase (PG) activity, whereas aerobic isolates did not produce any acid PG activity, but only an alkalophylic one, suggesting they could play a minor role in the retting process, except in the early stages. Analysis of 16S rDNA sequences assigned anaerobic strains to the Clostridium genus and aerobic isolates to the Bacillus and Paenibacillus genus. C. felsineum and C. acetobutylicum were confirmed as the main anaerobic agents. Nevertheless, a high proportion of anaerobic and aerobic pectinolytic strains was assigned to C. saccharobutylicum and B. pumilus, respectively, both species never being described as involved in water retting. Anaerobic and aerobic strains with high PG activity were selected and characterized. PG activity is well correlated with the strain retting efficiency and improvement of the process was obtained by inoculating the retting water with spores of selected aerobic and anaerobic bacteria. An advisable feature of retting strains is the absence of cellulosolytic activity. An aerobic strain with no cellulosolytic activity was identified. In contrast, all the anaerobic isolates showed cellulosolytic activity. Mutagenesis was ineffective for selection of Cel-Pec⁺ mutants. Localization of the C. felsineum L1/6 PG activity was investigated.  相似文献   

Effect of turbidity on the ultraviolet disinfection performance in recirculating aquaculture systems with low water exchange     

Mariel Gullian  Francisco J Espinosa‐Faller  Alicia Núñez  Norberto López‐Barahona 《Aquaculture Research》2012,43(4):595-606

This research was carried out to study the effect of turbidity on the effectiveness of ultraviolet light (UVC) for removing heterotrophic bacteria (HB) from two commercial recirculating aquaculture systems (RAS). We developed a simple and straightforward UV disinfection model based on water turbidity to predict the cost‐effectiveness of disinfection. The UVC from RAS1 (12.8 m³, 80 L min^?1, indoor system) was tested at 9.2, 9.9, 16.3, 17.2, 23.1 and 28.2 nephelometric turbidity units (NTU) after 24 h of exposure. The RAS2 (140 m³, 1140 L min^?1, outdoor system) was tested at 8.0, 9.2, 11.0, 12.1, 16.0, 24.2, 27.0, 31.3 and 31.7 NTU after 72 h. An increase in turbidity in the water was achieved by rearing Oreochromis niloticus fish. The RAS1 achieved a maximum UV efficiency (89.8%≈1 Log) at 9.2 NTU after 24 h and RAS2 at 8.0 NTU (86.4%≈0.9 Log) after 72 h of exposure. For RAS1, the UVC removed 90% of HB in 24 h when the turbidity was <9.9 NTU. For RAS2, without restrictions on particle size and relatively high phytoplankton abundance, the UV was unlikely to be a cost‐effective way of removing HB at turbidity above 11.0 NTU.  相似文献   

The effect of male absence on the larval production of the spider crab Maja brachydactyla Balss, 1922          下载免费PDF全文

Carles G Simeó  Mireia Andrés  Alicia Estévez  Guiomar Rotllant 《Aquaculture Research》2015,46(4):937-944

The spider crab Maja brachydactyla, Balss 1922 can produce three consecutive broods per breeding season in the wild, whereas females in captivity can spawn up to four times in the absence of males. The effect of male absence on the larval production of the spider crab M. brachydactyla was studied in a 2‐year experiment in which females were kept in captivity in the presence or absence of males. The broodstock were maintained under natural photoperiod conditions, temperature (18.5 ± 1.0°C) and salinity (34.8 ± 0.7 g L^?1). The number of larvae, and when possible, the dry weight and proximate biochemical composition of each larval batch were calculated and the data grouped seasonally. The larval production (P < 0.001) and protein content (P = 0.037) were significantly lower in the absence of males. However, considering that the larval production in male presence decreased due to the low female survival rate, particularly in the last part of the experiment, the presence of males should be managed to maintain a high larval production and condition without jeopardizing the survival of females. Therefore, we recommend keeping females segregated from males and transferring males to female tanks only to mate.  相似文献   

Effects of a peroxide-based commercial product on bacterial load of larval rearing water and on larval survival of two species of Sparidae under intensive culture: preliminary study     

Gemma Giménez-Papiol  Francesc Padrós  Ana Roque  Alicia Estévez  & Dolores Furones 《Aquaculture Research》2009,40(4):504-508

Larvae of two Mediterranean Sparidae species, Sparus aurata and Dentex dentex , were used to test the efficacy of a peroxide-based product (Ox-Aquaculture^©) on the reduction in bacterial load in larval rearing water and its effects on larval survival. Eleven-day-old S. aurata larvae and 15-day-old D. dentex larvae were exposed to different concentrations of Ox-Aquaculture^© (50, 100 and 200 mg L⁻¹, and 20 and 50 mg L⁻¹ respectively) for 1 h. Results indicated that 50 and 20 mg L⁻¹ were the most effective concentrations for the reduction in bacterial load (at least one order of magnitude) after 1 h treatment, without affecting larval survival and/or vitality in 11 dph S. aurata and 15 dph D. dentex larvae respectively. Ox-Aquaculture^© concentrations of 200 and 50 mg L⁻¹ during 1 h affected negatively final survival rate of the larvae of S. aurata and D. dentex respectively.  相似文献   

Effects of conjugated linoleic acid and curcumin on growth performance and oxidative stress enzymes in juvenile Pacific white shrimp (Litopenaeus vannamei) feed with aflatoxins     

Oscar Daniel García‐Prez  Mireya Tapia‐Salazar  Martha G. Nieto‐Lpez  Julio Csar Cruz‐Valdez  Maribel Maldonado-Muiz  Lucía Marlene Guerrero Guerrero  Lucía Elizabeth Cruz‐Surez  Alicia G. Marroquín-Cardona 《Aquaculture Research》2020,51(3):1051-1060

Aflatoxicosis is a growing problem in aquaculture. A 42‐day study was designed to evaluate the efficacy of conjugated linoleic acid (CLA) and curcumin (CUR) to protect juvenile Pacific white shrimp (Litopenaeus vannamei) from aflatoxins. Growth parameters along with alkaline phosphatase (ALP) and glutathione S‐transferase (GST) activities were measured. Shrimps (36) with an average weight of 76 ± 0.9 mg were randomly allocated in eight experimental groups. Non‐contaminated diet (NCD) and aflatoxin‐contaminated diet (ACD) at 200 μg/kg were prepared. ACD was used to prepare six diets supplemented with CLA (4, 5 or 6 g/kg) and CUR (0.15, 0.2 and 0.3 g/kg). ACD reduced feed intake, growth rate and nitrogen retention efficiency, and increased ALP and GST activity. Improved nitrogen retention was observed for all groups feed with CLA. CUR supplementation at 0.2 g/kg increased feed intake and growth rate while at 0.15 g/kg increased nitrogen retention. ALP activity was reduced in all CUR groups and in 5 and 6 g/kg CLA groups. Reduction in GST activity was observed in 0.15 and 0.2 g/kg CUR groups and 4 g/kg CLA group. CLA supplementation and CUR supplementation can be beneficial to protect juvenile shrimp against aflatoxins.  相似文献