Calcification of Intervertebral Discs in the Dachshund: A Radiographic Study of 21 Stud-Dogs

The vertebral columns of 21 clinically normal, 4.9 to 13.2 year old dachshunds were x-rayed. This sample represented 55.3% of all male dachshunds with 20 or more offspring registered with the Norwegian Kennel Club in the period 1985-1989. Calcified intervertebral discs were identified in 9 (42.9%) of the stud-dogs, and the number of calcified discs in each individual varied from 2 to 5 with a mean of 3.7. The frequency of stud-dogs with 1 or more calcified discs was compared with the corresponding frequency in a material of 327 one-year-old dachshunds. In this comparison, the relative risk was estimated with 95% confidence bounds. When the different composition of size and coat varieties in the 2 materials was not considered, the relative risk of calcified discs was found to be 1.77 (0.99-3.2) times higher in stud-dogs than in young dogs. When the different composition of varieties in the 2 materials was considered, the relative risk was found to be 1.9 (1.1-3.4) times higher in stud-dogs than in young dogs. The results of the present study strongly suggest that an increase in the frequency of dachshunds with 1 or more calcified intervertebral discs occurs after 1 year of age.     

Life history, growth and production of Mysis relicta in the large, fiord-type Lake Mjøsa, Norway

SUMMARY.

• 1 Biomass, production and life history of Mysis relicta were studied in the large Lake Mjøsa during the years 1976–80. Biomass fluctuations were large, but biomass averaged about 1 g wet wt m^?2 or 200 ind. m^?2. Cumulative net production during summer ranged from 1.6 to 2.1 g wet wt m^?2. Mean population P/B-ratio was close to 2.
• 2 Neither production or biomass of Mysis were correlated with the biomass of phytoplankton or the main Zooplankton prey species (Daphnia and Bosmina), suggesting a predominant ‘top down’ control of Mysis in this lake.
• 3 The life cycle was well synchronized with development of food items, but predation pressure also affected life-history patterns. The proportion of juveniles apparently increased in years with strong fish predation pressure, producing a predominantly 1-year life-cycle pattern the following year.
• 4 Mysis had a predominant 2-year life history, but a traction of the population may reproduce after 1 or 3 years. Reproduction occurred exclusively during winter. Even in such a large and stable system, where Mysis has coexisted with its main food items and predators for 8–10 000 years, a flexible life history is maintained and is probably an important buffer against year-to-year fluctuations in food and predator abundance.

     

Colonial breeding and speciation in birds

Summary It was recently suggested that bird species which breed colonially might be under stronger sexual selection, have faster rates of evolution and might therefore speciate more rapidly than bird species which do not. If true, then colonial taxa should contain more species than non-colonial taxa, other things being equal. When similarity through common descent is accounted for, there is little evidence for an association between the number of species in a clade and whether it is colonial or not.     

Identification of stool proteins in C57BL/6J mice by two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry

Gastrointestinal disease is a major cause of mortality in humans and animals, and the detection of disease-associated protein in stool is an established diagnostic method in this context. Yet, no data currently exists about the protein composition of mammalian faeces. Using a newly developed two-dimensional (2D) gel method, 28 of the most abundant proteins in murine faeces were identified. Mammalian faeces contains protein from multiple species (from the individual, from gastrointestinal bacteria, from food, etc.). Yet, it was found that the majority of mouse stool proteins were of mouse origin, with a minority of proteins being derived from food (in particular soybean glycinin and conglycinin) and bacteria (flagellin). Most mouse proteins were proteases and saccharidases derived from the exocrine pancreas. In addition, two unexpected mouse proteins were identified: one was a newly described mucin-like protein from intestinal goblet cells (FcγBP); the other was the secreted form of carbonic anhydrase (type VI) from salivary gland. The data suggest that 2D analysis of faecal protein is likely to provide meaningful information about the physiological stage of the gastrointestinal tract. Compared with studies based on biopsies, faecal protein analysis may reduce the number of laboratory animals, and might also allow quicker bridging from animal studies to humans, where biopsy material is more difficult to obtain and is less relevant for general practice use.     

Antimicrobial activity and structure of a consensus human β-defensin and its comparison to a novel putative hBD10

The spread of multidrug resistant bacteria owing to the intensive use of antibiotics is challenging current antibiotic therapies, and making the discovery and evaluation of new antimicrobial agents a high priority. The evaluation of novel peptide sequences of predicted antimicrobial peptides from different sources is valuable approach to identify alternative antibiotic leads. Two strategies were pursued in this study to evaluate novel antimicrobial peptides from the human β-defensin family (hBD). In the first, a 32-residue peptide was designed based on the alignment of all available hBD primary structures, while in the second a putative 35-residue peptide, hBD10, was mined from the gene DEFB110. Both hBDconsensus and hBD10 were chemically synthesized, folded and purified. They showed antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Mycobacterium tuberculosis, but were not hemolytic on human red blood cells. The NMR-based solution structure of hBDconsensus revealed that it adopts a classical β-defensin fold and disulfide connectivities. Even though the mass spectrum of hBD10 confirmed the formation of three disulfide bonds, it showed limited dispersion in ¹H NMR spectra and structural studies were not pursued. The evaluation of different β-defensin structures may identify new antimicrobial agents effective against multidrug-resistant bacterial strains.     

Late Ordovician brachiopods from eastern North Greenland: equatorial offshore migration of the Red River fauna

Abstract: Late Ordovician rhynchonelliformean brachiopods, typical of the North American Red River fauna, are found sporadically in the Børglum River Formation of the Centrum Sø area, Kronprins Christian Land, eastern North Greenland. The geographical distribution of this characteristic brachiopod fauna is thus extended to the easternmost extremity of the Laurentian craton. The assemblage compares specifically with the Hiscobeccus brachiopod fauna, based on key taxa such as notably Hiscobeccus gigas (Wang, 1949), and indicates a late Katian age for this part of the succession. For the first time, this typically inland, shallow‐water fauna is found associated with genera like Bimuria, suggesting a transitional marginal facies with outer shelf benthos. The current study describes a Hiscobeccus fauna that lived at the seaward edge of its preferred habitat. Furthermore, an unpublished Hiscobeccus fauna, from the Børglum River Formation of Peary Land, central North Greenland, as well as several occurrences from the Kap Jackson and Cape Calhoun formations in various parts of Washington Land, western North Greenland, are described here. These show a distinct shift from older strata containing H. capax (Conrad, 1842) to younger strata exclusively yielding specimens of H. gigas. As H. gigas occurs in the upper part of the Cape Calhoun Formation in Washington Land, it indicates that the upper boundary of the Cape Calhoun Formation is considerably younger than previous estimates, reaching into the uppermost Katian (middle Cautleyan–Rawtheyan). The Cape Calhoun Formation correlates with the upper member of the Børglum River Formation and further demonstrates that the Hiscobeccus fauna was widespread in Laurentian marginal settings of North Greenland. Even though the Hiscobeccus fauna was pan‐continental during the late Katian (Richmondian), it possesses a strong provincial signal during the later Ordovician. The new occurrences indicate that this fauna extended to the north‐eastern margin of the Laurentian Craton. It lived in close association with cosmopolitan faunal elements that may have been the earliest sign of the succeeding invasion of migrants from Baltica that arrived later during the Hirnantian. The offshore migration of this atypical Hiscobeccus fauna likely demonstrates the path of warm‐water currents as the Centrum Sø locality was located at the equator during the Late Ordovician.     

Nuisance growth of Juncus bulbosus: the roles of genetics and environmental drivers tested in a large‐scale survey

1. Invasive species can transform aquatic ecosystems, and the nuisance growth of the freshwater macrophyte Juncus bulbosus has become a problem in many lakes and rivers in northern Europe. It affects biodiversity strongly and conflicts with human uses, not least compromising the generation of hydroelectricity. The causes of the proliferation of these massive stands of J. bulbosus are not finally resolved, however. 2. In this study, a wide range of catchment, lake and sediment parameters (n = 34) were assessed for 139 lakes in Southern Norway, with the aim of explaining the presence or absence of J. bulbosus and to assess potential drivers behind its prolific growth. 3. Juncus bulbosus was more often present in lakes with lower pH and phosphate concentrations, and a higher element ratio of dissolved inorganic nitrogen (DIN) to total phosphorus (DIN : TotP). 4. Despite the many parameters measured across substantial environmental gradients, none explained nuisance growth. Genetic screening (amplified fragment length polymorphism fingerprinting) of plants from a subset of lakes and additional river sites also showed no genetic differences between the various growth forms. A macrophyte trophic index, however, suggested that the most problematic growth occurred in the most oligotrophic lakes. 5. The lack of consistent patterns may reflect either factors not assessed in our survey, or that the current extension of stands represents a gradual cumulative response over time, not characterised effectively in our snapshot survey. Nevertheless, we can now exclude some putative causes of nuisance growth, including in particular genetics and N‐deposition.     

Fertility of gynogenetic Atlantic cod (Gadus morhua L.)

In order to investigate whether meiotic gynogenetic Atlantic cod is fertile and able to produce viable offspring, meiotic gynogenetic females were produced in spring 2010 by activating cod eggs using irradiated sperm. The extrusion of the second polar body was prevented by the application of hydrostatic pressure (56.6 MPa) 36 min after fertilization. In February 2012, their mean round weight was 972 g, and 2580 g in March 2013. In 2012, when the fish were 2 years old, about 52% were mature, 33% were immature, and 13% had undifferentiated gonads. One year later, 77% were mature, 11% were immature, and 11% had undifferentiated gonads. Several of the mature females had malformed gonads, with only one developed ovary lobe or with the two lobes fused. The mean gonadosomic index (GSI) of the 2‐year‐old mature females was 5.2%, with an estimated relative fecundity of 581 000 eggs kg ovary‐free wet weight^?1. Females were stripped for eggs when 2 and 3 years old (2012 and 2013), and fertilized with sperm from normal males. Offspring were obtained from 12 of 17 and 12 of 15 egg batches incubated in 2012 and 2013, respectively, proving that the gynogenetic females are fertile. Furthermore, larvae in all but one of the hatched groups from 2013 had commenced feeding 2 h after being startfed using rotifers 4 days after hatch, indicating viable offspring.