Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance

By using newly hatched (approximately 2 weeks old) brown trout(Salmo trutta) from six families of wild and six families ofsea-ranched origin (seventh generation), we tested the hypothesesthat (1) the hatchery environment selects for increased boldness,and (2) boldness predicts dominance status. Sea-ranched troutspend their first 2 years in the hatchery before being releasedinto the wild at the onset of seaward migration. Trout werepresented with a novel object (tack) and with food (brine shrimp),and their responses were measured and scored in terms of boldness.Siblings with increasing difference in boldness were then pairedin dyadic contests. Fish of sea-ranged origin were on averagebolder than were fish of wild origin, and bolder individualswere more likely to become dominant regardless of origin. Boldnesswas not related to RNA levels, indicating that bold behaviorwas not a consequence of higher metabolism or growth rate. Neitherwas size a predictor of bold behavior or the outcome of dyadiccontests. These results are consistent with studies on olderlife stages showing increased boldness toward predators in hatchery-selectedfish, which suggests that behavioral consequences of hatcheryselection are manifested very early in life. The concordancebetween boldness and dominance may suggest that these behaviorsare linked in a risk prone-aggressive phenotype, which may bepromoted by hatchery selection. However, we also found significantvariation in behavioral and growth-related traits among families,suggesting that heritable variation has not been exhausted bysea-ranching procedures.     

Folate-dependent enzymes in cultured Chinese hamster ovary cells: evidence for mutant forms of folylpolyglutamate synthetase

A Chinese hamster ovary auxotroph requiring glycine + adenosine + thymidine (CHO AUXB1) was shown by us previously to lack several folylpolyglutamate synthetase (FPGS) type activities. Two revertants of AUXB1 (one spontaneous and one Pt(S0₄)₂ induced) have been isolated and found to contain altered forms of this enzyme. The revertant enzymes are more sensitive to heat inactivation (37 °C, pH 7.4 or 9.0) than the parent CHO enzyme. Increased sensitivity of revertant FPGS is observed irrespective of whether one assays the specific catalysis of radioactive tetrahydropteroyldi- or tetraglutamate synthesis. ATP and MgCl₂ protect both revertant and parent CHO FPGS against rapid heat denaturation at pH 9.0, but not at pH 7.4. A genetically related auxotroph (CHO AUXB3) contains one-fifth the parent amount of FPGS. AUXB3 FPGS shows a normal sensitivity to 37 °C heat inactivation, but it has an altered substrate saturation and specificity pattern when assayed for tetrahydropteroyldi[U-¹⁴C]glutamate synthesis. Also, unlike the FPGS from parent CHO and a genetically unrelated mutant requiring only glycine (CHO AUXB2), the AUXB3 enzyme specifically lacks tetrahydropteroyltetra[U-¹⁴C]glutamate synthetase activity. These findings and polyethylene glycol fusion data with AUXB2 indicate that AUXB1 and AUXB3 each carry a mutation in the structural gene for a CHO FPGS that catalyzes tetrahydropteroyldi- as well as tetraglutamate formation. The altered form of FPGS in AUXB3 is responsible for its glycine + adenosine auxotrophy under standard culture conditions.     

Aerobic photolysis of alkylcobalamins: quantum yields and light-action spectra

Quantum yields (φ) for the aerobic photolysis of 5′-deoxyadenosylcobalamin (dAB₁₂), methylcobalamin (MeB₁₂), propylcobalamin (PrB₁₂), and ethylcobalamin (EtB₁₂) were determined as a function of the irradiation wavelength. φ Determinations were made for both the base-on and base-off forms of each compound (except base-off dAB₁₂) at incident wavelengths from 250 nm to 570 nm. As a rule, the φs were high (0.1–0.5) and they varied significantly with respect to the irradiation wavelength. In general, each alkylcobalamin at pH 7.0 displayed a quantum yield spectrum distinct from its base-off form at pH 1.0. Across most of the spectrum, the φs of the base-off form were appreciably smaller than the base-on φs of the same compound. An exception to this generality was MeB₁₂ for which the φs at pH 1.0 were about the same as, or slightly greater above 450 nm than those at pH 7.0. At pH 7.0 and in the visible region the trend of the φs was dAB₁₂ < MeB₁₂ < PrB₁₂ < EtB₁₂. Under neutral conditions each compound showed a broad quantum yield peak in the 450–470 nm region.From the quantum yield and absorption spectra, photolysis spectra were calculated for 5.0 × 10^?5m solutions of each compound. The light-action spectra accurately give the relative rates/μ Einstein that these solutions photolyze at each wavelength. Thus, for example, MeB₁₂ photolyzed faster at pH 7.0 versus pH 1.0 in 510 nm light, but it photolyzed slower at pH 7.0 versus pH 1.0 in 450 nm light. Solutions of each compound photolyzed faster in the ultraviolet region as opposed to the visible (e.g., 310 nm versus 510 nm).Our findings show that the previously reported photolysis rates estimated by others with tungsten lamps provide no valid information about the intrinsic photolability of various alkyl-cobalt bonds. This also applies to the relative white-light photolysis rates reported for the base-on versus the base-off form of MeB₁₂. All such relative rates are artifacts which represent only the extent of overlap between the true action spectrum and the light emission spectrum of an incandescent lamp.     

Direct acid-catalysed transmethylation of lactobacillic acid in lactic acid bacteria

Summary Cellular fatty acids inLactobacillus büchneri were transmethylated with H₂SO₄ catalyst in methanol at elevated temperature. By optimising the reaction time and the amounts of catalyst and methanol used at a fixed temperature it was possible to maximise the lactobacillic acid yield. The yield of lactobacillic acid with this method was better than with the traditional method using base-catalysed saponification followed by HCL-catalysed methylation.     

Use of oligonucleotide probes to study the relatedness of delta-endotoxin genes among Bacillus thuringiensis subspecies and strains

Fifteen Bacillus thuringiensis strains representing 13 serotypes were screened with five oligodeoxyribonucleotide probes specific for certain regions of two published sequences and one unpublished sequence of B. thuringiensis delta-endotoxin genes. Of the 15 cultures, 14 hybridized with at least one probe; the B. thuringiensis subsp. thompsoni strain alone did not hybridize. Two B. thuringiensis subsp. kurstaki strains of commercial interest, HD-1 and NRD-12, were found to be so closely related as to be indistinguishable with this technique; the same situation was found with strains from B. thuringiensis subspp. dendrolimus and sotto. Five strains were identified as probably containing only one endotoxin gene. A probe specific for the gene from the B. thuringiensis subsp. kurstaki HD-73 strain hybridized to only 3 of the 15 cultures tested. The hybridization data suggest that the DNA sequences coding for the C-terminal region of the endotoxin protein are as well conserved as those coding for the N-terminal toxic portion.