Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach

Stapanian MA, Witzel LD, Cook A. Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach.
Ecology of Freshwater Fish 2010: 19: 326–337. Published 2010. This article is a US Government work and is in the public domain in the USA Abstract – World‐wide, many burbot Lota lota (L.) populations have been extirpated or are otherwise in need of conservation measures. By contrast, burbot made a dramatic recovery in Lake Erie during 1993–2001 but declined during 2002–2007, due in part to a sharp decrease in recruitment. We used Akaike’s Information Criterion to evaluate 129 linear regression models that included all combinations of one to seven ecological indices as predictors of burbot recruitment. Two models were substantially supported by the data: (i) the number of days in which water temperatures were within optimal ranges for burbot spawning and development combined with biomass of yearling and older (YAO) yellow perch Perca flavescens (Mitchill); and (ii) biomass of YAO yellow perch. Warmer winter water temperatures and increases in yellow perch biomass were associated with decreases in burbot recruitment. Continued warm winter water temperatures could result in declines in burbot recruitment, particularly in the southern part of the species’ range.     

Changes in hematological, blood gas, and serum biochemical variables in broilers during exposure to simulated high altitude.

One-day-old broilers were reared until 35 days of age at both natural low (100 m) and simulated high altitude (2133 m) to assess the incidence and development of ascites syndrome. Clinical measurements were conducted at 7, 14, 21, 28, and 35 days of age. Birds reared at 2133 meters exhibited significantly (P less than or equal to 0.05) reduced body weights at 7 through 28 days of age. Total serum calcium and biochemical enzyme activities were found to be altered at 35 days of age. In addition, the high-altitude group had significantly (P less than or equal to 0.05) higher erythrocyte counts, hematocrits, and hemoglobin at 14, 21, 28, and 35 days of age and higher serum inorganic phosphorus at each weekly sample time than birds at the low altitude. Total mortality was 20.3% at 2133 meters and 4.6% at 100 meters. The incidence of ascites syndrome in the high-altitude group ranged from 16.6% to 61.1% during the 5-week experimental period.     

Interactive Effects of High Boron and NaCl Stresses on Subcellular Localization of Chloride and Boron in Wheat Leaves

Salinity and boron (B) toxicity often occur simultaneously and may have interactive effects on plant responses. This study aims at further investigating long‐term effects of salinity, B toxicity and their combination on wheat plants. Plants grown in hydroponics were treated with 2.5 μm H₃BO₃ (control), 75 mm NaCl, 200 μm H₃BO₃ or 75 mm NaCl + 200 μm H₃BO₃ and were analysed on a subcellular level 6 weeks after germination. Shoot fresh and dry weight (DW), water content, transpiration rate and osmolality were reduced, while Na⁺ and Cl^? concentrations increased under salinity stress. However, Cl^? was reduced in all compartments by an additional application of B toxicity. At adequate B supply, NaCl increased apoplastic and symplastic soluble B concentrations, whereas the total B content remained unchanged. At high B level, however, soluble and total B was reduced by additional salt stress. Despite this antagonistic effect of a combined salt and B toxicity stress on Cl^? and B concentrations, an additive effect was observed regarding shoot fresh weight reduction. Our results confirm an alleviating effect of the combined stresses on toxic ion concentrations, which did not prevent additive growth reductions.     

Loss of imprinting of Igf2 alters intestinal maturation and tumorigenesis in mice

Loss of imprinting (LOI) of the insulin-like growth factor II gene (IGF2) is an epigenetic alteration that results in a modest increase in IGF2 expression, and it is present in the normal colonic mucosa of about 30% of patients with colorectal cancer. To investigate its role in intestinal tumorigenesis, we created a mouse model of Igf2 LOI by crossing female H19+/- mice with male Apc+/Min mice. Mice with LOI developed twice as many intestinal tumors as did control littermates. Notably, these mice also showed a shift toward a less differentiated normal intestinal epithelium, reflected by an increase in crypt length and increased staining with progenitor cell markers. A similar shift in differentiation was seen in the normal colonic mucosa of humans with LOI. Thus, altered maturation of nonneoplastic tissue may be one mechanism by which epigenetic changes affect cancer risk.     

Microsomal activation of constituents of white snakeroot (Eupatorium rugosum Houtt) to form toxic products

Components of white snakeroot, a plant toxic to livestock and human beings, were activated by Aroclor 1254-induced rat liver microsomes. The toxic products of microsomal activation were evaluated in murine melanoma (B16F1) cell cultures. Toxic products in white snakeroot were inactive in cell culture systems without microsomal activation. This activation system revealed that at least 2 fractions of white snakeroot were metabolically activated to cytotoxic agents. The autocatalytic inactivator of cytochrome P-450, 1-aminobenzotriazole, inhibited activation of white snakeroot constituents by rat liver microsomes.     

Arsanilic acid-induced blindness in swine: electroretinographic and visually evoked responses.

Arsanilic acid (1,000 ppm) caused blindness in pigs within 25 to 30 days. The visually evoked response was "nonrecordable" in blind pigs, but was consistently recordable in normal pigs. The electroretinographic response was recordable in both normal and blind pigs, and significant differences were not apparent between results of tests of the 2 groups. Optic disk atrophy was noted ophthalmoscopically; lesions of the optic nerve are probably responsible for the nonrecordable visually evoked response.