“A cleaner break”: Genetic divergence between geographic groups and sympatric phenotypes revealed in ballan wrasse (Labrus bergylta)

Capture and long‐distance translocation of cleaner fish to control lice infestations on marine salmonid farms has the potential to influence wild populations via overexploitation in source regions, and introgression in recipient regions. Knowledge of population genetic structure is therefore required. We studied the genetic structure of ballan wrasse, a phenotypically diverse and extensively used cleaner fish, from 18 locations in Norway and Sweden, and from Galicia, Spain, using 82 SNP markers. We detected two very distinct genetic groups in Scandinavia, northwestern and southeastern. These groups were split by a stretch of sandy beaches in southwest Norway, representing a habitat discontinuity for this rocky shore associated benthic egg‐laying species. Wrasse from Galicia were highly differentiated from all Scandinavian locations, but more similar to northwestern than southeastern locations. Distinct genetic differences were observed between sympatric spotty and plain phenotypes in Galicia, but not in Scandinavia. The mechanisms underlying the geographic patterns between phenotypes are discussed, but not identified. We conclude that extensive aquaculture‐mediated translocation of ballan wrasse from Sweden and southern Norway to western and middle Norway has the potential to mix genetically distinct populations. These results question the sustainability of the current cleaner fish practice.     

Structure of the human neutrophil elastase gene

The gene for human neutrophil elastase (NE), a powerful serine protease carried by blood neutrophils and capable of destroying most connective tissue proteins, was cloned from a genomic DNA library of a normal individual. The NE gene consists of 5 exons and 4 introns included in a single copy 4-kilobase segment of chromosome 11 at q14. The coding exons of the NE gene predict a primary translation product of 267 residues including a 29-residue N-terminal precursor peptide and a 20-residue C-terminal precursor peptide. Analysis of the N-terminal peptide sequence suggests it contains a 27-residue "pre" signal peptide followed by a "proN" dipeptide, similar to that of other blood cell lysosomal proteases. The sequences for the mature 218-residue NE protein are included in exons II-V. The 5'-flanking region of the gene includes typical TATA, CAAT, and GC sequences within 61 base pairs (bp) of the cap site. The sequence 1.5 kilobases 5' to exon I contains several interesting repetitive sequences including six tandem repeats of unique 52- or 53-bp sequences. The 5'-flanking region also contains a 19-bp segment with 90% homology to a segment of the 5'-flanking region of the human myeloperoxidase (MPO) gene, a gene also expressed in bone marrow precursor cells and a protein stored in the same neutrophil granules as NE. In addition, like the MPO gene, the NE 5'-flanking region has several regions with greater than or equal to 75% homology to sequences 5' to c-myc, but there is no overlap between the NE-c-myc and MPO-c-myc homologous sequences.     

Structure and localization of genes encoding aberrant and normal epidermal growth factor receptor RNAs from A431 human carcinoma cells.

A431 cells have an amplification of the epidermal growth factor (EGF) receptor gene, the cellular homolog of the v-erb B oncogene, and overproduce an aberrant 2.9-kilobase RNA that encodes a portion of the EGF receptor. A cDNA (pE15) for the aberrant RNA was cloned, sequenced, and used to analyze genomic DNA blots from A431 and normal cells. These data indicate that the aberrant RNA is created by a gene rearrangement within chromosome 7, resulting in a fusion of the 5' portion of the EGF receptor gene to an unidentified region of genomic DNA. The unidentified sequences are amplified to about the same degree (20- to 30-fold) as the EGF receptor sequences. In situ hybridization to chromosomes from normal cells and A431 cells show that both the EGF receptor gene and the unidentified DNA are localized to the p14-p12 region of chromosome 7. By using cDNA fragments to probe DNA blots from mouse-A431 somatic cell hybrids, the rearranged receptor gene was shown to be associated with translocation chromosome M4.     

Uptake of guanine by synchronizedChlorella fusca

1. The transport of guanine in autospores of light-dark synchronizedChlorella fusca was studied using radioactive guanine in the concentration range of 4 nM to 50 μM.
2. The transport system was constitutive, it had high specificity for the permeant, and theQ ₁₀ value was in the range of 1.5 to 2.2. At concentrations lower than 0.2 μM the half saturating constant, S_0.5 was 1 μM both for cells kept in dark and cells kept in light. At higher concentrations the S_0.5 of darkened cells was about 0.23 μM, while that of illuminated cells was unchanged. Only above 0.2 μM guanine did illumination of the cells or addition of glucose increase the transport rate.
3. Guanine which had accumulated did not leak out at temperatures below 45°C or by treatment with 10 μM dinitrophenol, which completely inhibited transport. Furthermore, the accumulated guanine did not exchange with exogenous guanine.
4. The guanine accumulated, more than 10⁵-fold over the external concentration, showing that the transport, was active.
5. The initial transport rate per cell revealed annual fluctuations.

     

Effect of zinc on increasing oxygen affinity of sickle and normal red blood cells

We have hypothesized a state of zinc deficiency in sickle cell disease (SCD). This could at least partially explain the growth problems, hypogonadism, and slow healing leg ulcers associated with SCD. Preliminary findings revealed abnormally low red blood cell zinc levels in 10 of 16 patients studied. Before suggesting zinc supplementation in SCD we thought it important to look at the effect of zinc on red cell metabolism and function. It was found that zinc chloride added to normal and SCD blood to a final concentration of 1.5 × 10^?3 M caused a left-shift of the blood oxygen affinity curve (increased oxygen affinity) varying from 1.5 to 3.5 mm Hg change in half saturation (p50). This curve shifting property has important implications for SCD since recent work with cyanate suggests that such shifts are very beneficial in treatment of SCD. Thus zinc supplementation in SCD, in addition to its potential role in correcting wound healing and growth problems, may have a beneficial effect on the basic pathological process. Data are given which suggest that zinc and 2, 3-diphosphoglycerate may not be competing for the same site on the hemoglobin molecule.     

Body growth in Atlantic walruses (Odobenus rosmarus rosmarus) from Greenland

Morphometric data were collected from 105 Atlantic walruses ( Odobenus rosmarus rosmarus ) in northwestern Greenland in the periods 1977–78 and 1989–91. Of these 21 walruses were subjected to a detailed study on body composition.
The asymptotic maximum standard body length of Atlantic walruses in NW Greenland was 269 cm for females and 314 cm for males. This is similar to Pacific walruses, but significantly longer than Atlantic walruses from Hudson Bay. Despite this, walruses from NW Greenland apparently do not attain the same total body mass as Pacific walruses ( O.r.divergens ).
The asymptotic maximum body weights for walruses in NW Greenland were estimated to be 720 kg for females and 1114 kg for males.
Total body surface area was proportional to the two-thirds power of total body weight.
The percentage proportion of blubber and viscera were both negatively correlated to body mass, while skin and muscles constituted a nearly fixed proportion. On average, blubber constituted 19% of total body mass of adult females, 15% of adult males and 24% of subadults of both genders. The average walrus consisted of 18% blubber, 12% skin, 12% viscera and 58% blood, muscle and skeleton. Muscles were estimated to constitute 44% of total body weight.
Allometric functions for weight of internal organs relative to body mass are presented.     

Molecular cut-off values of dialysis membranes for alginate and kappa-carrageenan oligosaccharides

The effective molecular weight cut-off values of dialysis membranes for carrageenan and alginate oligosaccharides were evaluated by gel permeation chromatography and nuclear magnetic resonance spectroscopy. For the different membranes tested, i.e. Medicell, Spectra Por 1000D and 3500D, the porous sizes are analogous to tri- and tetrasaccharides. A simple dialysis can be used to recover the majority of the oligosaccharides produced by a carrageenase or an alginate lyase digestion.     

The synthesis and biochemical evaluation of new A1 selective adenosine receptor agonists containing 6-hydrazinopurine moieties

The synthesis and SAR of a series of novel derivatives of N-aminoadenosine is described, along with their in vitro effects in biochemical assays. The rat brain A₁ adenosine receptor binding of these compounds is very dependent upon the purine 2-substituent. The novel agonist, 2-chloro-N-[4-(phenylthio)-1-piperidinyl]adenosine, exhibits a L_i value for A₁ receptor binding of <1 nM.     

Influence of light and temperature on photoinhibition of photosynthesis inSpirulina platensis

Photoinhibition of photosynthesis and its recovery in the cyanobacteriumSpirulina platensis was studied to find how photosynthetic rates were influenced by light and temperature. By exposing cell samples from a turbidostat culture to combinations of light and temperature, a connection between light, temperature and photoinhibition was found. The experiments showed that a 10 degree increase from 20 °C to 30 °C considerably reduced the photoinhibition. At 25 °C a photon flux density of 1720 µmol m^–2 s^–1 reduced the photosynthetic rate by 50 % in 1 h, but a similarly high photon flux density had nearly no negative effect at 35 °C. Reactivation in low light from 50% photoinhibition was fast and complete in 60 min at 30 °C, while at 20 °C only about 1/6 of the full capacity was regained in the same time. Addition of the protein synthesis inhibitor streptomycin to cultures undergoing photoinhibition and regeneration indicated the presence also in this organism of a repair mechanism based on protein synthesis.Author for correspondence     

Carbohydrate degradation and methane production during fermentation ofLaminaria saccharina (Laminariales,Phaeophyceae)

Anaerobic digestion of the brown algaLaminaria saccharina (L.) Lamour. harvested in spring and autumn was carried out at controlled laboratory conditions in stirred fermentor systems. Due to the normal seasonal variations, the autumn material had a much higher content of carbohydrates such as mannitol and laminaran. Both batch and semi-continuous feeding conditions were investigated for periods up to 800 h, with inoculum provided from previous kelp fermentations. In batch cultures, the methane yield from the autumn material was doubled compared to that of the spring material. Semi-continuous conditions gave more similar methane yields for both raw materials, 0.22 and 0.27 l CH₄ per g VS for spring and autumn material, respectively. In all experiments, mannitol and laminaran were reduced to less than 5 of the initial values within 24–48 hours after inoculation, whereas 30 of the alginate content was detectable even after 30 days. Viscometry revealed that this material was severely depolymerized, and alginate lyase activity was found to develop rapidly in all cultures. Although mannitol and laminaran were fermented much faster than alginate, the total accumulated methane yields seemed to be determined by the total carbohydrate content of the raw material during extended semi-continuous feeding.(*author for correspondence)