Weight, Length, and Growth in Cutbow Trout (Oncorhynchus mykiss x clarkii)

Background: The cutbow trout (Oncorhynchus mykiss x clarkii) is a fertile hybrid of rainbow and cutthroat trout. Little published length-weight data is available for this hybrid, and a standard weight curve is not established. Eleven Mile Reservoir is a clear mountain reservior in Colorado with a surface area of 13.4 square kilometers, an average depth of 10 m, and a maximum depth of 41 m. 80,000 cutbow trout were stocked through the ice in late winter before samples were taken.
Materials and Methods: Angling provided 171 samples which were weighed and measured (total length and fork length). Dressed weight was also determined with the scales, head, and entrails removed. Estimates of parameters a and b in the model, W(L) = aLb, were obtained by both linear least-squares (LLS) regression (log(W) = log(a) + b log(L)) and non-linear least-squares (NLLS) regression, where W is weight in kg and L is length in cm. Parameter estimates of an improved model, W(L) = (L/L1)b, were also determined by NLLS regression; the parameter L1 is the typical length of a fish weighing 1 kg. The resulting best-fit parameters, parameter standard errors, and covariances are compared between the two models. Average weight and length are considered for each month from June through October to estimate growth rates for fish stocked over the winter. Standard weights (relative to the rainbow trout and cutthroat trout standard weight curves) are also determined, along with the ratio of total length to fork length and typical dressed weight percentage. 
Results: The improved model parameter estimates were b = 2.662 and L1 = 45.32 cm, with correlation coefficient r = 0.969. From June to October, mean relative weight decreased from 101.5% to 93.6% relative to the rainbow trout standard weight and 114.5% to 103.2% relative to the cutthroat trout standard weight as mean total lengths increased from 34.4 cm to 41.9 cm and the mean weights increased from 0.505 kg to 0.830 kg. Typical dressed weight is 71% of the total weight. 
Conclusion: Eleven mile reservoir is an excellent trout fishery, capable of producing large numbers of cutbow trout in good condition. The cutbow trout is well suited to this kind of mountain reservoir and grows fast. As might be expected, the weights of cutbow trout of a given length tend to fall between the standard weights of the rainbow and the cutthroat. For the season, the average relative weight was 97.0% relative to the rainbow trout, and 108.3% relative to cutthroat trout.
&#xa

Fingerprinting triangular-lattice antiferromagnet by excitation gaps

CeCd3As3 is a rare-earth triangular-lattice antiferromagnet with large interlayer separation. Our field-dependent heat capacity measurements at dilution fridge temperatures allow us to trace the field evolution of the spin-excitation gaps throughout the antiferromagnetic and paramagnetic regions. The distinct gap evolution places strong constraints on the microscopic pseudospin model, which, in return, yields a close quantitative description of the gap behavior. This analysis provides crucial insights into the nature of the magnetic state of CeCd3As3, with a certainty regarding its stripe order and low-energy model parameters that sets a compelling paradigm for exploring and understanding the rapidly growing family of the rare-earth-based triangular-lattice systems

Identification, Purification, and Characterization of Iminodiacetate Oxidase from the EDTA-Degrading Bacterium BNC1

Microbial degradation of synthetic chelating agents, such as EDTA and nitrilotriacetate (NTA), may help immobilizing radionuclides and heavy metals in the environment. The EDTA- and NTA-degrading bacterium BNC1 uses EDTA monooxygenase to oxidize NTA to iminodiacetate (IDA) and EDTA to ethylenediaminediacetate (EDDA). IDA- and EDDA-degrading enzymes have not been purified and characterized to date. In this report, an IDA oxidase was purified to apparent homogeneity from strain BNC1 by using a combination of eight purification steps. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a single protein band of 40 kDa, and by using size exclusion chromatography, we estimated the native enzyme to be a homodimer. Flavin adenine dinucleotide was determined as its prosthetic group. The purified enzyme oxidized IDA to glycine and glyoxylate with the consumption of O(2). The temperature and pH optima for IDA oxidation were 35°C and 8, respectively. The apparent K(m) for IDA was 4.0 mM with a k(cat) of 5.3 s(−1). When the N-terminal amino acid sequence was determined, it matched exactly with that encoded by a previously sequenced hypothetical oxidase gene of BNC1. The gene was expressed in Escherichia coli, and the gene product as a C-terminal fusion with a His tag was purified by a one-step nickel affinity chromatography. The purified fusion protein had essentially the same enzymatic activity and properties as the native IDA oxidase. IDA oxidase also oxidized EDDA to ethylenediamine and glyoxylate. Thus, IDA oxidase is likely the second enzyme in both NTA and EDTA degradation pathways in strain BNC1

Gamete fertility and ovule number variation in selfed reciprocal F1 hybrid triploid plants are heritable and display epigenetic parent-of-origin effects

Polyploidy and hybridization play major roles in plant evolution and reproduction. To investigate the reproductive effects of polyploidy and hybridization in Arabidopsis thaliana, we analyzed fertility of reciprocal pairs of F1 hybrid triploids, generated by reciprocally crossing 89 diploid accessions to a tetraploid Ler-0 line. All F1 hybrid triploid genotypes exhibited dramatically reduced ovule fertility, while variation in ovule number per silique was observed across different F1 triploid genotypes. These two reproductive traits were negatively correlated suggesting a trade-off between increased ovule number and ovule fertility. Furthermore, the ovule fertility of the F1 hybrid triploids displayed both hybrid dysgenesis and hybrid advantage (heterosis) effects. Strikingly, both reproductive traits (ovule fertility, ovule number) displayed epigenetic parent-of-origin effects between genetically identical reciprocal F1 hybrid triploid pairs. In some F1 triploid genotypes, the maternal genome excess F1 hybrid triploid was more fertile, whilst for other accessions the paternal genome excess F1 hybrid triploid was more fertile. Male gametogenesis was not significantly disrupted in F1 triploids. Fertility variation in the F1 triploid A.thaliana is mainly the result of disrupted ovule development. Overall, we demonstrate that in F1 triploid plants both ovule fertility and ovule number are subject to parent-of-origin effects that are genome dosage-dependent