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关键词： Mycobacterium tuberculosis   FtsY   SRP pathway   GTP   CD   SIGNAL-RECOGNITION PARTICLE   ELONGATION-FACTOR-TU   ESCHERICHIA-COLI   PROTEIN-STRUCTURE   ATPASE ACTIVITY   RECEPTOR   GTP   BINDING   FFH   EXPRESSION  

摘要： Mycobacterium tuberculosis (M. tuberculosis H(37)Rv) utilizes the signal recognition particle pathway (SRP pathway) system for secretion of various proteins from ribosomes to the extracellular surface which plays an important role in the machinery running inside the bacterium. This system comprises of three major components FtsY, FfH and 4.5S rRNA. This manuscript highlights essential factors responsible for the optimized enzymatic activity of FtsY. Kinetic parameters include V-max and K-m for the hydrolysis of GTP by ftsY which were 20.25 +/- 5.16 mu M/min/mg and 39.95 +/- 7.7 mu M respectively. k(cat) and catalytic efficiency of the reaction were 0.012 +/- 0.003 s(-1) and 0.00047 +/- 0.0001 mu M/s(-1) respectively. These values were affected upon changing the standard conditions. Cations (Mg2+ and Mn2+) play important role in FtsY enzymatic activity as increasing Mg2+ decrease the activity. Mn2+ on the other hand is required at higher concentration around 60 mM for carrying optimum GTPase activity. FtsY is hydrolyzing ATP and GDP as well and GDP acts as an inhibitor of the reaction. MD simulation shows effective binding and stabilization of the FtsY complexed structure with GTP, GDP and ATP. Mutational analysis was done at two important residues of GTP binding motif of FtsY, namely, GXXXXGK (K236) and DXXG (D367) and showed that these mutations significantly decrease FtsY GTPase activity. FtsY is comprised of alpha helices, but this structural pattern was shown to change with increasing concentrations of GTP and ATP which symbolize that these ligands cause significant conformational change by variating the secondary structure to transduce signals required by downstream effectors. This binding favors the functional stabilization of FtsY by destabilization of alpha-helix integrity. Revealing the hidden aspects of the functioning of FtsY might be an essential part for the understanding of the SRP pathway which is one of the important contributors of M. tuberculosis v

关键词： Anesthetic   Stress   Physiology   Metabolism   GRATISSIMUM ESSENTIAL OIL   JUVENILE TAMBAQUI   PHYSIOLOGICAL-RESPONSES   OREOCHROMIS-NILOTICUS   SPILANTHES-ACMELLA   RHAMDIA-QUELEN   NILE TILAPIA   CLOVE OIL   STRESS   L.  

摘要： The present study evaluated the efficacy of Ocimum basilicum (basil) essential oil in the anesthetic induction and recovery of juvenile tambaqui Colossoma macropomum and verified its physiometabolic effects after biometric handling. Juveniles (86.51 +/- 7.82 g) were exposed to different concentrations of basil essential oil: 400, 500, 600, 700, 800, 900, and 1000 mu L L-1. Subsequently, the fish were divided into five groups: control (non-handled fish), handling without anesthetic (water only), handling with ethanol (720 mu L L-1), and handling with Ocimum basilicum essential oil (400 and 800 mu L L-1). The shortest (p < 0.05) time to induce anesthesia was at a concentration of 1000 mu L L-1 (222 s). The recovery time from anesthesia did not differ significantly among different concentrations (400-1000 mu L L-1). The results of the present study confirm the essential oil of O. basilicum as a new and safe natural anesthetic for juvenile tambaqui. The use of this essential oil in biometrics handling procedures reduces or attenuates the secondary responses to handling stress without showing deleterious effects on the non-specific immune system or metabolism of energy, carbohydrates, and lipids. However, further studies are necessary to determine the exact mechanism of action of this essential oil.

关键词： Fish disease   Oreochromis niloticus   Antimicrobial peptide   Streptococcus agalactiae   RESPIRATORY BURST ACTIVITY   FISH   IDENTIFICATION   MICROBIOTA   INFECTION   INDICATOR   BACTERIA   STRESS  

摘要： Among the antimicrobial peptides (AMPs), which act as natural antibiotics in preventing the colonization of pathogens, LL-37 is noteworthy. It is a human cathelicidin characterized as a broad-spectrum antibiotic, with chemotactic and immunomodulatory properties. This study aimed to evaluate the antimicrobial activity and therapeutic effectiveness of peptide LL-37 against streptococcosis caused by Streptococcus agalactiae in Nile tilapia and to assess some of its potential adverse effects (in vivo haematological, biochemical, and immunological profiles) in the fish. After in vitro cytotoxicity studies of LL-37 against Nile tilapia red blood cells (RBCs) and antimicrobial susceptibility testing (minimum inhibitory concentration and minimum bactericidal concentration, MIC and MBC, respectively) against Aeromonas hydrophila and S. agalactiae, fish were divided into six experimental groups. G1 and G2 were challenged by intraperitoneal injection with S. agalactiae and received a single oral dose of LL-37 (15 mg/kg bw) and florfenicol (FFC) (15 mg/kg bw), respectively. G3 was challenged with S. agalactiae and received a single intraperitoneal dose of LL-37 (15 mg/kg bw). The other groups were controls for infection (G4) and antimicrobial administration (G5 and G6). LL-37 showed weak hemolytic activity against Nile tilapia RBCs (24.4% lysis at 625 mu g/mL) and strong in vitro antimicrobial activity against S. agalactiae (MIC and MBC = 31.25 mu g/mL). No significant effects were observed in the haematological, biochemical, and immunological profiles of fish medicated with LL-37 or FFC, compared to the control fish. Twenty days after the challenge, survival rates were 33.38% (G1), 38.51% (G2), 23.12% (G3), 25% (G4), and 100% (G5 and G6). Despite the strong in vitro antimicrobial activity, both antimicrobials were ineffective to control streptococcosis caused by S. agalactiae in Nile tilapia. These findings suggest that administration of LL-37 (15 mg/kg bw) is safe for Nile ti

关键词： Water additives   Yucca schidigera   Yeast   Nile tilapia   Growth   Water quality   Welfare   Oxidative stress   GLYCOCOMPONENTS DE-ODORASE   CHALLENGED IN-SITU   LIVE BAKERS-YEAST   AEROMONAS-HYDROPHILA   SHIDIGERA EXTRACT   HEMATOLOGICAL PARAMETERS   DENITRIFYING BACTERIA   DISEASE RESISTANCE   IMMUNE-RESPONSE   ENZYME-ACTIVITY  

摘要： The current study was carried out to assess the effects of aqueous extract of yucca, Yucca schidigera (YE) and/or yeast, Saccharomyces cerevisiae, used as water additives on the performance of Nile tilapia, Oreochromis niloticus. Fish (28-32 g) were randomly situated in 12 2-m(3) concrete ponds at a density of 20 fish per m(3) and assigned to four treatments in triplicates where the control ponds were not received any additive (the control) as well as ponds received YE only, yeast only, or both YE + yeast. YE and/or yeast were added daily to ponds water at levels of 1.0 g YE/m(3) and/or 1.0 g yeast/m(3) for 8 weeks. Neither water temperature nor dissolved oxygen were significantly affected by YE and/or yeast treatment; but pH and NH3 levels were significantly reduced (P < 0.05) by these water additives especially at the YE + yeast treatment. The growth performance of Nile tilapia was significantly improved (P < 0.05) by these water additives and highest growth performance was observed in fish treated with YE + yeast. In contrast, YE and/or yeast treatments did not affect levels of glucose, alanine aminotransferase, and alkaline phosphatase. However, levels of serum total lipids, total protein, albumin, and globulin were higher (P < 0.05) in fish treated with YE + yeast than those observed in the control fish. Adding YE and/or yeast to ponds water significantly decreased levels of aspartate aminotransferase, uric acid, and creatinine (P < 0.05) in fish, especially with the YE + yeast treatment. In addition, significant higher activities of superoxide dismutase, catalase, and glutathione pemxidase, with significant lower malondialdehyde value, were observed in fish treated with YE + yeast (P < 0.05). Overall, these results suggest that using 1.0 g/L of both YE + yeast as water additives improved water quality by reducing pH and ammonia levels, which appears to improve the fish growth and reduce the oxidative stress in Nile tilapia.

关键词： Herbal additives   Rainbow trout   Ammonia toxicity   Nutrition   Health   GROWTH-PERFORMANCE   COMMON CARP   IMMUNE-RESPONSE   ANTIOXIDANT STATUS   ENZYME-ACTIVITIES   OXIDATIVE STRESS   ALLIUM-SATIVUM   ORGANIC-ACIDS   LINN. CALYX   SKIN MUCUS  

摘要： The present study aimed to assess immunostimulation and anti-inflammation effects of dietary Roselle, Hibiscus sabdariffa, on rainbow trout, Oncorhynchus mykiss, under normal conditions as well as following ammonia exposure. For this, the fish (similar to 8 g) were divided into three groups and fed diets containing 0 (R0), 0.5 (R0.5) and 1 (R1) % Roselle mill for 60 days, then exposed to 0.3 mg/L unionized ammonia nitrogen for 24 h as a factorial design. According to the results, 0.5% dietary Roselle inclusion showed significantly higher final weight, weight gain (%), feed conversion ratio, and specific growth rate. Moreover, results showed that dietary Roselle supplementation significantly increased blood WBC, plasma total immunoglobulin (Ig), alternative complement (ACH50), and bactericidal activity, and skin mucus/plasma lysozyme activity. Moreover, dietary Roselle significantly decreased plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and hepatic expression of tumor necrosis factor alpha (tnfa), interleukin-1 beta (il1b), interleukin-8 (il8), and heat shock protein 70 (hsp70) gene expression. Exposure to ammonia significantly increased plasma ammonia and blood WBC levels. Moreover, ammonia exposure significantly increased plasma ALT and AST activities, and hepatic gene expressions, and decreased plasma or mucus total Ig, lysozyme, ACH50 and bactericidal activity; Roselle administration mitigated such changes. In conclusion, the present study demonstrated that Roselle is capable to augment immune and to mitigate inflammation in rainbow trout, which lead to higher health following ammonia toxicity. Dietary 0.5-1% Roselle supplementation is recommended for trout feed formulation.

关键词： INNATE IMMUNE-RESPONSE   LACTIC-ACID BACTERIA   SALMO-SALAR L.   HEMATOLOGICAL PARAMETERS   ORGANIC-ACIDS   NUTRIENT DIGESTIBILITY   GASTROINTESTINAL-TRACT   DISEASE RESISTANCE   MICROBIAL PHYTASE   FEED-UTILIZATION  

摘要： An 84 days experimental trial was undertaken to examine the influence of potassium diformate (KDF) and Lactobacillus acidophilus and their interaction on growth, biochemical of blood parameters, enzymes of antioxidant response and intestinal topography of Nile tilapia, Oreochromis niloticus, fingerlings fed fishmeal free diets. Six functional diets were formulated to contain two levels of L. acidophilus (0, 1.47 x 10(7) CFU kg(-1)), with each level being supplemented with 0, 5 g and 10 g KDF kg(-1) diet, respectively. Fingerlings O. niloticus (n = 540; initial weight 4.29 +/- 0.06 g) were randomly allocated into six groups (30 fish group(-1) in triplicates). The results showed that the best values of growth, feed efficiency and biological parameters were recorded by fish fed diets containing 1.47 x 10(7 )L. acidophilus CFU kg(-1) and 10 g kg(-1) KDF. Lower pH values in stomach and gut were noted in fish fed diet supplemented with 1.47 x 10(7) L. acidophilus CFU kg(-1 )and 10 g kg(-1) KDF. Diets supplemented with L. acidophilus, KDF or in combination improved the hemoglobin, red blood cells and white blood cells count with insignificant differences among groups. The activities of serum alanine and aspartate aminotransferase decreased significantly (P < 0.05) by the addition of L. acidophilus and KDF in fish diets. Furthermore, addition of KDF and L. acidophilus significantly (P < 0.05) improved the serum total protein and albumin, but globulin not affected. The lowest value of uric acid was recorded in fish fed 5 g kg(-1) KDF without addition of L. acidophilus, while there were no significant (P > 0.05) differences in creatinine content were found among treatments. Diets supplemented with L. acidophilus and/or KDF significantly (P < 0.05) improved phosphorus and calcium content. However, the activities of superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and catalase (CAT) were highest in fish fed diet contained either 5 g or 10 g kg(-1) KDF and 1.47 x 1

关键词： Growth rate   Reactive oxygen species   Antioxidant   Phthalates   Thymoquinone   N-BUTYL PHTHALATE   FRESH-WATER FISH   CLARIAS-GARIEPINUS BURCHELL   NILE TILAPIA   BISPHENOL-A   DNA-DAMAGE   ESTERS   EXPOSURE   TOXICITY   IMMUNE  

摘要： The current study assessed the ameliorative potential of Nigella sativa seeds against diethyl phthalate (DEP) induced growth retardation, oxidative stress and histo-biochemical changes in Labeo rohita (rohu) fingerlings. N. sativa, a medicinal plant containing several pharmacological properties, was incorporated into three diets at 0%, 1%, and 2.5% levels, prepared by mixing N. sativa seeds with the basal diet. The median lethal concentration of DEP to mhu was 4.38 mg L-1 for 96th hour. Three hundred fingerlings (8.502 +/- 0.009 g) were exposed to a sub-lethal concentration of 0.51 mg L-1 (1/10th of LC50) DEP, with or without N. sativa for 7, 14, 21, and 28 days. The results revealed that rohu exposed to DEP alone has significantly decreased growth rate, as opposed to rohu exposed to DEP in combination with N. saliva, which demonstrated markedly improved growth rates. A significant decrease in muscles protein contents of DEP-treated rohu was also noted. DEP exposure also inhibited the antioxidant enzymes (catalase, glutathione-S-transferase and glutathione peroxidase) activities in all of the studied tissues (liver, kidney, gills and brain). Moreover, DEP exposure significantly increased lipid peroxidation levels, whereas glutathione (GSH) levels decreased in all of the studied rohu tissues in a time-dependent manner. Where DEP exposure has been found to enhance alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, urea, and creatinine levels; a significant reversal in the levels of these enzymes was noted in N. saliva supplemented rohu. Histological studies of the liver, kidney, and gills indicated that N. saliva supplementation in mhu provides beneficial protective defenses against DEP-induced toxicity.

关键词： Integrated multi-trophic aquaculture (IMTA)   Media filled beds (MFB)   Biochemical transformations of nitrogen compounds   AQUAPONICS SYSTEM   AMMONIUM   DENITRIFICATION   CHALLENGES   EFFICIENCY   OXIDATION   DYNAMICS   YIELD   PH  

摘要： Quantitative and qualitative transformations of nitrogen compounds in the Integrated Multi-Trophic Aquaculture (IMTA) system using the Media Filled Beds (MFB) method in plant cultivation was investigated experimentally. Three fish tanks were populated with 200 individuals of common carp (Cyprinus carpio L.) in each. The experiment lasted over three months. The following parameters were determined on the weekly basis: ammonium nitrogen, nitrate (III) nitrogen, nitrate (V) nitrogen, total nitrogen, mineral nitrogen, organic nitrogen and dissolved oxygen, according to commonly adopted methods. Water samples for the analyses were taken directly from the fish tanks and locations directly after each type of filtration (mechanical, biological and hydroponic). The presence of all determined forms of nitrogen was established including the mineral nitrogen which concentration remained at levels sufficient for a normal growth and development of plants. Active nitrification process was detected. Loss of nitrogen from the system was not only due to absorption by plants. Initiation of the anaerobic ammonia oxidation (anammox) and denitrification processes was observed.

关键词： PROTEIN-KINASE-A   ADENYLYL-CYCLASE   CAMP   CORTEX   CELL   COPULATION   DURATION   PHOSPHORYLATION   SECRETION   SELECTION  

摘要： Neural network computations are usually assumed to emerge from patterns of fast electrical activity. Challenging this view, we show that a male fly's decision to persist in mating hinges on a biochemical computation that enables processing over minutes to hours. Each neuron in a recurrent network contains slightly different internal molecular estimates of mating progress. Protein kinase A (PKA) activity contrasts this internal measurement with input from the other neurons to represent accumulated evidence that the goal of the network has been achieved. When consensus is reached, PKA pushes the network toward a large-scale and synchronized burst of calcium influx that we call an eruption. Eruptions transform continuous deliberation within the network into an all-or-nothing output, after which the male will no longer sacrifice his life to continue mating. Here, biochemical activity, invisible to most large-scale recording techniques, is the key computational currency directing behavior and motivational state.