Correlations between circulating insulin-like growth factor-I and thyroxine and cortisol hormone levels,and some biometrical traits in female brood stocks during the late stages of sex maturation and in juvenile Persian sturgeon (<Emphasis Type="Italic">Acipenser persicus</Emphasis>)

Relationships between insulin-like growth factor-I (IGF-I) and thyroxine (T4) and cortisol hormones were studied in female brood stocks of Persian sturgeon [Acipenser persicus; caught from both sea water (SW) and fresh water (FW)] during late stages of sex maturation. A number of biometrical traits were also studied that could represent the reproductive and/or growth states of brood stocks, and the possible relationship between IGF-I and growth was assessed in juvenile Persian sturgeons between 1 and 4 years of age. IGF-I, T4 and cortisol were measured in serum samples using commercially available kits. A four-parameter logistic model test was performed between the standard curves and the sample dilutions for each hormone. Parallelism, linearity and regression coefficients for the linearized standard curves and serial dilutions of samples were not significantly different (P < 0.05). Serum IGF-I levels in the juveniles were higher than those in the SW brood stocks, and cortisol levels in the former were lower than those in both brood stocks (P < 0.05). T4 levels in serum samples of juveniles were below the detectable level. IGF-I concentrations in juveniles were correlated with total weight, total length and fork length, but they did not increase significantly with increasing age from 1 to 4 years old (P < 0.05). Compared with SW brood stock, the FW brood stock was younger, had a smaller girth, smaller polarization index and higher ova diameter (P < 0.05). There were no differences between IGF-I and T4 levels in the two brood stocks, but cortisol levels were significantly higher in the FW brood stock. Percentage of fertilization was correlated with serum IGF-I in both brood stocks (P < 0.05). Our results support a role for IGF-I during the juvenile growth and reproductive physiology in female brood stocks of the Persian sturgeon.     

Stereochemical Trajectories of a Two-Component Regulatory System PmrA/B in a Colistin-Resistant Acinetobacter baumannii Clinical Isolate

Background:There is limited information on the 3D prediction and modeling of the colistin resistance-associated proteins PmrA/B TCS in Acinetobacter baumannii. We aimed to evaluate the stereochemical structure and domain characterization of PmrA/B in an A. baumannii isolate resistant to high-level colistin, using bioinformatics tools. Methods:The species of the isolate and its susceptibility to colistin were confirmed by PCR-sequencing and MIC assay, respectively. For 3D prediction of the PmrA/B, we used 16 template models with the highest quality (e-value <1 × 10−50). Results:Prediction of the PmrA structure revealed a monomeric non-redundant protein consisting of 28 α-helices and 22 β-sheets. The PmrA DNA-binding motif displayed three antiparallel α-helices, followed by three β-sheets, and was bond to the major groove of DNA by intermolecular van der Waals bonds through amino acids Lys, Asp, His, and Arg, respectively. Superimposition of the deduced PmrA 3D structure with the closely related PmrA protein model (GenBank no. {"type":"entrez-protein","attrs":{"text":"WP_071210493.1","term_id":"1098418292"}}WP_071210493.1) revealed no distortion in conformation, due to Glu→Lys substitution at position 218. Similarly, the PmrB protein structure displayed 24 α-helices and 13 β-sheets. In our case, His251 acted as a phosphate receptor in the HisKA domain. The amino acid substitutions were mainly observed at the putative N-terminus region of the protein. Furthermore, two substitutions (Lys21→Ser and Ser28→Arg) in the transmembrane domain were detected. Conclusion: TheDNA-binding motif of PmrA is highly conserved, though the N-terminal fragment of PmrB showed a high rate of base substitutions. This research provides valuable insights into the mechanism of colistin resistance in A. baumannii. Key Words: Acinetobacter baumannii, Amino acid substitution, Colistin, Mutation     

Interpretation of correlations between coagulation factors FV, FVIII and vWF in normal and type 2 diabetes mellitus patients

Increased risk of vascular diseases in hypercoagulable states is assumed to be the major cause for prevalence of vascular problems in type 2 diabetes mellitus patient. The present study was undertaken to explore the basis underlying the correlation between the aforesaid three coagulation factors with reference to the relevant mechanistic findings using statistical calculation. Our findings showed that the correlation between each pairs of coagulation factors, FV, FVIII and vWF could be easily interpreted using previously characterized interactions between these factors. Also, given the sequence similarities between FV and FVIII as well as the results of this study, it was indicated, for the first time, that FV may bind to vWF in the same way as FVIII binds. This finding seems to be of great importance to be evaluated through experimental techniques.     

Effect of grape seed extract on lead induced hypertension and heart rate in rat

The main objective of this study was to evaluate the potential protective effect of red Grape Seed Extract (GSE) on lead induced hypertension (HTN) and Heart Rate (HR) in male Wistar rats. The rats were randomly assigned to one of 4 groups: Each group received lead acetate (100 ppm in drinking water), GSE (100 mg kg(-1), orally) or Lead + GSE for 45 days. Another group assigned as control group provided with tap water and regular pellet food. The Systolic Blood Pressure (SBP) and heart rate were determined by tail plethysmography coupled to a computer system. There was a sustained elevation of SBP in lead exposed rats that significantly increased at day 18 (lead treated, 112.7 +/- 2.7 mmHg, vs. control, 105.6 +/- 2.6 mmHg, n = 10, p < 0.05) and reached a maximum level at day 36 (lead treated, 124.9 +/- 2.3 mmHg, vs. control, 103.6 +/- 3.1 mmHg, n = 10, p < 0.001). However, the other three groups; showed no significant changes in SBP. Furthermore, the heart rate was increased sustainly in lead exposed animals that was statistically significant at days 36 and 45 (lead treated group, 404.5 +/- 9.4 vs. control group, 381.7 +/- 6.7, n = 10, p < 0.05). The blood lead level in both lead and lead + GSE treated groups was increased significantly compared with control and GSE treated groups (p < 0.001). However, GSE administration had no effect on the blood lead level in lead treated group. According to the result of this study, it may be concluded that GSE could have beneficial effect in protecting the cardiovascular system through its antioxidant activity against oxidative stress.     

The influence of the El Niño Southern Oscillation on paralarval market squid (Doryteuthis opalescens)

California market squid (Doryteuthis opalescens) support one of the largest and most valuable fisheries in California. However, market squid abundance varies greatly from year to year, ostensibly as a result of the El Niño Southern Oscillation (ENSO) phenomenon, although the underlying mechanism is not known. Classic hypotheses suggest that the early larval stage may be the key to uncovering this mechanism. Here, we perform a time series analysis, length‐distribution analysis, and growth analysis to investigate the effects of ENSO on paralarval D. opalescens. In contrast to classic hypotheses, we find that ENSO does not drive early paralarval survival or growth. Instead, we find that the ENSO operates primarily on the late paralarval stage, with El Niño conditions associated with lower survival of late‐stage paralarvae. We also find that time series models which use ENSO conditions during the previous juvenile and adult stage outperform models that use ENSO conditions during the paralarval stage. Our results suggest that the population bottleneck for D. opalescens does not occur in the early paralarval stage, but instead lies later in the squid's life.     

Effect of Dietary Prebiotic Inulin on Growth Performance,Intestinal Microflora,Body Composition and Hematological Parameters of Juvenile Beluga,Huso huso (Linnaeus, 1758)

Use of prebiotics, nondigestible dietary ingredients that beneficially affect the host by selectively stimulating the growth of and/or activating the metabolism of health‐promoting bacteria in the intestinal tract, is a novel concept in aquaculture. An 8‐week feeding experiment was conducted to investigate the effects of dietary prebiotic inulin on growth performance, intestinal microflora, body composition and hematological parameters of juvenile beluga, Huso huso. Three replicate groups of fish (initially averaging weight as group 16.14 ± 0.38 g) were fed diets containing prebiotic inulin levels ranging from 1 to 3%. The basal diet contained 3% cellulose. Fish were fed to apparent satiation and growth performance was monitored. The results of linear regression showed that there was a negative relationship between some performance indices including weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), energy retention (ER), feed efficiency (FE), protein retention (PR), and supplementation level of inulin, which indicated that inulin is not appropriate for supplementation in the diet of beluga. At the end of trial, in both basal and inulin groups, the total count of intestinal bacteria decreased within the second 4 weeks, but the intestinal lactic acid bacteria (LAB) increased in the 1% inulin group. These changes were not, however, reflected in the survival rate of the fish, although survival was higher compared to other groups.     

Population ecological parameters and biomass of anchovy kilka <Emphasis Type="Italic">Clupeonella engrauliformis</Emphasis> in the Caspian Sea

ABSTRACT:   Through most of the last century, three endemic kilka species supported major commercial species in the Caspian Sea. It is clear that catches and abundance of all species have changed, but catch and sampling data are limited and stock assessments are inadequate. Recent changes in the Caspian Sea ecosystem have occurred as a consequence of climatic environmental change (sea level change) and ecologic change caused by the invasive ctenophore Mnemiopsis leidyi . This paper examines the effects of these changes on the population biology and biomass of anchovy kilka Clupeonella engrauliformis in Iranian waters of the Caspian Sea from 1995 to 2004. For most years during this 10-year period, we estimated the age structure of catch, length–weight relationship, von Bertalanffy growth parameters, condition factors, sex ratios, maturity stages determined from ovarian analysis, natural and fishing mortality, age at first capture, and spawning biomass. The instantaneous coefficient of natural mortality was estimated as 0.473/year and the instantaneous coefficient of fishing mortality varied during the 10-year period between 0.541 and 2.690/year. Biomass of anchovy kilka declined from about 186 000 t in 1996 to less than 12 000 t in 2004. Recent high fishing rates were not sustainable after the introduction of Mnemiopsis , so overfishing is part of the explanation for the collapse of anchovy kilka in the Caspian Sea.     

Molecular mobility of fish flesh measured by low-field nuclear magnetic resonance (LF-NMR) relaxation: effects of freeze–thaw cycles

In this study, the molecular mobility of fish flesh was measured by low field nuclear magnetic resonance (LF-NMR) relaxation. Sardine, tuna and mackerel were frozen at ?40 °C and stored for 1 day (24 h); and then these samples were thawed at room temperature (20 °C). The relaxation of water protons in fish flesh was measured for fresh (i.e., before freezing) and multi-cycle freeze–thaw samples (i.e., up to 12 times). Three domains from different pools of protons (i.e., low-mobile, medium-mobile and high-mobile) were identified from the relaxation curve. The T _2b (low-mobile), T ₂₁ (medium-mobile) and T ₂₂ (high-mobile) indicated the proton populations in the protein molecules, strongly bound water molecules, and weakly bound water molecules, respectively. In all cases, the relaxation time (T _2b: sardine r = 0.736 and p < 0.01, tuna r = 0.857 and p < 0.001, mackerel r = 0.904 and p < 0.001; and T ₂₂: sardine r = 0.956 and p < 0.0001, tuna r = 0.927 and p < 0.0001, mackerel r = 0.890 and p < 0.0001) increased with the freeze–thaw cycles and it reached a nearly constant value after 6 freeze–thaw cycles. The increased relaxation time (i.e., higher mobility) up to 6 freeze–thaw cycles could be due to the increase in proton mobility. However, relaxation time (T ₂₁: sardine r = ?0.510 and p > 0.05, tuna r = 0.162 and p > 0.5, mackerel r = 0.513 and p > 0.01) showed insignificant change with the increase of freeze–thaw cycles, which indicated minimal change in the medium-mobile protons. The results in this study revealed that the changes in proton mobility in the fish flesh during freeze–thaw cycles could be identified using T _2b and T ₂₂ relaxation of LF-NMR.