15 research outputs found
Screening of enzyme activity for assessing the condition of larvae in the seven-band grouper Epinephelus septemfasciatus and devil stinger Inimicus japonicus
Do herbivorous minnows have âplug-flow reactorâ guts? Evidence from digestive enzyme activities, gastrointestinal fermentation, and luminal nutrient concentrations
Few investigations have empirically analyzed fish gut function in the context of chemical reactor models. In this study, digestive enzyme activities, levels of gastrointestinal fermentation products [short chain fatty acids (SCFA)], luminal nutrient concentrations, and the mass of gut contents were measured along the digestive tract in herbivorous and carnivorous minnows to ascertain whether their guts function as âplug-flow reactorsâ (PFRs). Four of the species, Campostoma anomalum, C. ornatum, C. oligolepis, and C. pauciradii, are members of a monophyletic herbivorous clade, whereas the fifth species, Nocomis micropogon, is a carnivore from an adjacent carnivorous clade. In the context of a PFR model, the activities of amylase, trypsin and lipase, and the concentrations of glucose, protein, and lipid were predicted to decrease moving from the proximal to the distal intestine. I found support for this as these enzyme activities and nutrient concentrations generally decreased moving distally along the intestine of the four Campostoma species. Furthermore, gut content mass and the low SCFA concentrations did not change (increase or decrease) along the gut of any species. Combined with a previous investigation suggesting that species of Campostoma have rapid gut throughput rates, the data presented here generally support Campostoma as having guts that function as PFRs. The carnivorous N. micropogon showed some differences in the measured parameters, which were interpreted in the contexts of intake and retention time to suggest that PFR function breaks down in this carnivorous species
Genomic organization of repetitive DNAs highlights chromosomal evolution in the genus Clarias (Clariidae, Siluriformes)
Identifying an efficient bacterial species and its genetic erosion for arsenic bioremediation of gold mining soil
To improve bioremediation of arsenic (As) contamination in soil, the use of microorganisms to efficiently reduce As and their assessment of genetic erosion by DNA damage using genomic template stability (GTS) evaluation and using RAPD markers were investigated. The five sites examined for microorganisms and contaminated soils were collected from affected gold mining areas. The highest As concentration in gold mining soil is 0.72 mg/kg. Microorganism strains isolated from the gold mining soil samples were tested for As removal capacity. Two bacterial isolates were identified by 16S rRNA gene sequence analysis and morphological characteristics as Brevibacillus reuszeri and Rhodococcus sp. The ability to treat As in nutrient agar (NA) at 1,600 mg/L and contaminated soil samples at 0.72 mg/kg was measured at 168 h, revealing more efficient As removal by B. reuszeri than Rhodococcus sp. (96.67% and 94.17%, respectively). Both species have the capacity to remove As, but B. reuszeri shows improved growth compared to the Rhodococcus sp. B. reuszeri might be suitable for adaptation and use in As treatment. The results are in agreement with their genetic erosion values, with B. reuszeri showing very little genetic erosion (12.46%) of culture in As concentrations as high as 1,600 mg/L, whereas 82.54% genetic erosion occurred in the Rhodococcus sp., suggesting that Rhodococcus sp. would not survive at this level of genetic erosion. Therefore, B. reuszeri has a high efficiency and can be used for soil As treatment, as it is capable to tolerate a concentration of 0.72 mg/kg and as high as 1,600 mg/L in NA
Cadmium, chromium, and lead accumulation in aquatic plants and animals near a municipal landfill
Digestibilidade aparente dos nutrientes e energia de ração suplementada com enzimas digestivas exógenas para juvenis de tambaqui (Colosssoma macropomum Cuvier, 1818) Apparent digestibility of nutrients and crude energy in diets with addition of exogenous digestive enzymes in tambaqui juveniles ( Colosssoma macropomum Cuvier, 1818)
O experimento foi conduzido com o objetivo de avaliar o efeito da adição de um compelxo multienzimĂĄtico exĂłgeno composto de amilase, protease, lipase e celulase, em raçÔes de juvenis de tambaqui, sobre os coeficientes de digestibilidade aparente (CDa) da proteĂna bruta (PB), extrato etĂ©reo (EE), carboidratos (ENN) e energia bruta (EB). O delineamento experimental foi inteiramente casualizado com quatro tratamentos (quatro nĂveis de inclusĂŁo de enzimas, 0,0; 0,05; 0,10; e 0,15 %), trĂȘs repetiçÔes (no tempo) e 10 peixes por unidade experimental. Foram utilizados 40 juvenis de tambaqui, com peso mĂ©dio de 155,0 ± 0,49 g, distribuĂdos em quatro tanques de alimentação de 500 l, recebendo refeiçÔes Ă vontade das 8 Ă s 12h, a cada hora. Em seguida os animais foram transferidos para coletores de fezes (200 l), onde permaneceram atĂ© Ă s 18h, sendo a coleta de dejetos realizada a cada hora. A determinação dos CDa foi realizada pelo mĂ©todo indireto, sendo utilizado como indicador externo 0,5% de Ăłxido de cromo-III (Cr2O3) incorporado Ă ração. Os resultados demonstraram que a suplementação das dietas com enzimas exĂłgenas para juvenis de tambaqui aumenta a digestibilidade aparente dos nutrientes e energia bruta, no nĂvel de inclusĂŁo de 0,05% (P<0,05%).<br>The experiment evaluated the effect of dietary supplementation a multienzyme complex containing amylase, protease, lipase and cellulase for tambaqui juveniles on the apparent digestibility coefficients (ADCs) of crude protein (CP), ether extract (EE), carbohydrates (CHO) and crude energy (CE). A completely randomized experimental design was used with four treatments (level of enzymes 0.0; 0.05; 0.10; and 0.15 %) and three replicates (over time), with ten fish per experimental unity. Forty fish weighting 155.0 ± 0.49g were distributed in four 500 l feeding tanks and were fed hourly, from 8 to 12 AM. After this period, fish were transferred for fecal collection units until 6 PM, where feces were collected hourly. ADCs were evaluated by an indirect method, with 0.5 % III-chromic oxide (Cr2O3) as innert marker. The results showed that supplementary exogenous enzymes on tambaqui diets increased the apparent digestibility of nutrients and crude energy at inclusion level of 0.05% (P<0.05%)