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At least 613 records · Page 34Linked to original sources
PubMed2002

Cellularity changes in developing red and white fish muscle at different temperatures: simulating natural environmental conditions for a temperate freshwater cyprinid.

Muscle cellularity patterns in teleost fish have normally been investigated using animals reared under constant temperature conditions. In the present study, Danube bleak (Chalcalburnus chalcoides mento) were reared under two different rising temperature regimes (cold, 12-16 degrees C; warm, 18-20 degrees C) designed to mimic the natural conditions experienced by the fish in temperate freshwater environments. Samples were taken from both groups of animals at intervals during their development. Transverse sections at the level of the anal vent were examined using light and electron microscopy, histochemistry and immunohistochemistry techniques. Total cross-sectional area of red and white muscle, as well as fibre numbers and fibre cross-sectional areas of one epaxial quadrant per specimen, were measured. Analysis of fibre numbers and sizes indicated that white and red myotomal muscles each develop in a different manner. In white muscle, the initial growth phase is dominated by fibre hypertrophy, while the later larval growth phase also includes significant hyperplasia. Red muscle growth is mainly due to hypertrophy within the studied developmental period. The temperature regimes applied in the present study may modify the mechanisms of muscle growth in different ways. For white muscle, pre-hatching hyperplasia (i.e. proliferation of somitic white fibre precursor cells) is reduced under the cold regime whereas post-hatching hyperplasia is not. The inverse is true for white fibre hypertrophy. A similar situation is seen with red muscle except that post-hatching hyperplasia is low and refractory to temperature. Rates of increase in relative amount of red muscle appear to depend not only upon species and temperature but also upon whether the fish have been reared under changing or constant thermal regimes. These findings are discussed in relation to 'landmark' events of early ontogeny (hatching, onset of swimming, start of exogeneous feeding) and to their implications for future accurate interpretation of temperature effects on teleost developmental biology and functional ecology.

Animals↗
PubMed1989

Effect of intraventricular injection of muscimol on appetite in rats kept at high and temperate ambient temperatures.

The central mechanism controlling food intake in response to the change in environmental temperature has been little examined. The GABA agonist, muscimol, was injected into the lateral ventricle of rats which were acclimated to temperate (26 degrees C) and hot (33 degrees C) environments. Muscimol obviously stimulated the feeding behavior of rats in both environments. However, when muscimol was administered at doses of 100 and 250 ng, the food intake at 26 degrees C was greater than that at 33 degrees C. In addition, the stimulating effect of muscimol (250 ng) on food intake at 26 degrees C lasted longer than that at 33 degrees C. These findings suggested that there might be a difference in muscimol metabolism at the two temperatures.

Acclimatization↗
PubMed2006

Maize adaptation to temperate climate: relationship between population structure and polymorphism in the Dwarf8 gene.

To investigate the genetic basis of maize adaptation to temperate climate, collections of 375 inbred lines and 275 landraces, representative of American and European diversity, were evaluated for flowering time under short- and long-day conditions. The inbred line collection was genotyped for 55 genomewide simple sequence repeat (SSR) markers. Comparison of inbred line population structure with that of landraces, as determined with 24 SSR loci, underlined strong effects of both historical and modern selection on population structure and a clear relationship with geographical origins. The late tropical groups and the early "Northern Flint" group from the northern United States and northern Europe exhibited different flowering times. Both collections were genotyped for a 6-bp insertion/deletion in the Dwarf8 (D8idp) gene, previously reported to be potentially involved in flowering time variation in a 102 American inbred panel. Among-group D8idp differentiation was much higher than that for any SSR marker, suggesting diversifying selection. Correcting for population structure, D8idp was associated with flowering time under long-day conditions, the deletion allele showing an average earlier flowering of 29 degree days for inbreds and 145 degree days for landraces. Additionally, the deletion allele occurred at a high frequency (>80%) in Northern Flint while being almost absent (<5%) in tropical materials. Altogether, these results indicate that Dwarf8 could be involved in maize climatic adaptation through diversifying selection for flowering time.

Alleles↗
PubMed2000

Variability of bio-optical factors influencing the seasonal attenuation of ultraviolet radiation in temperate coastal waters of Japan

The study identifies the relative contribution of various bio-optical factors to the total attenuation of ultraviolet radiation (UVR) wavelengths and photosynthetically active radiation (PAR) in temperate coastal waters of Japan by surveying the physical properties of the water column, UVR and PAR penetration, and the absorption characteristics of dissolved and particulate material. Spectral absorbance properties of pigment (aph), detritus (ad) and chromophoric dissolved organic material (aCDOM) displayed both seasonal and wavelength specific variability. On an annual basis, absorbance by aCDOM was the highest absorbing fraction (47-59%) for the UVR wavelengths measured (305, 320, 340 and 380 nm) but decreased (32%) at 450 nm. Contribution of pigments to total absorbance was highest (40-60%) during a spring bloom for both UVR and PAR. A large variability (C.V. > 42%) for annual average attenuation coefficients (Kd[lambda]) at respective wavelengths observed suggests that the spectral composition of the water column changes throughout the year in this region. A significant relationship was observed between Kd(lambda) and aCDOM at 305, 320, 340 and 380 nm only (P < 0.01) but not for 450 nm (PAR) indicating the role of CDOM in regulating variations in Kd(lambda), particularly in the UVR range. The slope S, obtained from a natural-log plot of the absorption coefficient of CDOM against wavelength, ranged between 0.014 and 0.036 nm-1 annually (average = 0.020 +/- 0.007, C.V. = 35%) and suggests seasonal changes in the origin of CDOM between terrestrial (low S) and biogenous (high S) CDOM.

Journal Article↗
PubMedDate not supplied

Interspecific variation in UV defense mechanisms among temperate freshwater fishes.

An important step in predicting the effects of future increases in UV radiation (UVR) is to evaluate the mechanisms that organisms use to prevent and repair DNA damage and determine how those mechanisms influence UVR sensitivity. Damage is prevented to varying degrees through photoprotection and repaired via two main pathways: nucleotide excision repair and photoenzymatic repair. At present, little is known about the generality or similarity of these defenses among temperate freshwater fishes. We used laboratory experiments to compare UVR defense mechanisms among five freshwater fish species representing four families and three orders. Purified DNA, freeze-killed larvae and live larvae were exposed to UVB radiation for 12 h in the presence or absence of photorepair radiation. After exposure, we quantified frequencies of cyclobutane pyrimidine dimers in each exposure treatment. All five species used photoprotection and proportional decreases in dimer frequency were similar for all species. Evidence of excision repair was also found for all species but proportional decreases in photoproduct frequencies varied among species. Finally, evidence of photoenzymatic repair was found for only two of the five species.

Animals↗
PubMed2002

Eye injury after jellyfish sting in temperate Australia.

Although jellyfish stings are an uncommon medical problem in temperate Australia, significant morbidity can occur, particularly in association with infestations of large numbers of jellyfish in public swimming areas. We report a case of a jellyfish sting-related eye injury, probably caused by the "hair" jellyfish (Cyanea capillata) from southeast Australia. The patient, a 54-year-old man, was stung while swimming without goggles in a jellyfish-infested bay. He experienced severe pain in his right eye, requiring narcotic analgesia, and had decreased visual acuity associated with right-sided facial swelling. Although usually brief and self-limiting, eye injuries after jellyfish stings should be assessed and treated as early as possible to reduce the risk of longer term sequelae. Water safety campaigns should incorporate information on the prevention and early treatment of such stings.

Animals↗
PubMed2001

Resistance of temperate Chinese elms (Ulmus spp.) to feeding by the adult elm leaf beetle (Coleoptera: Chrysomelidae).

Newly acquired Ulmus species from the temperate regions of China growing at The Morton Arboretum, Lisle, IL, were evaluated in laboratory bioassays for feeding preference and suitability for larvae and adults of the elm leaf beetle, Pyrrhalta luteola (Müller). Larval and adult no-choice and adult multiple-choice feeding studies revealed that U changii, U. lanceaefolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis were the least suitable for feeding and reproduction by the elm leaf beetle. Ulmus wallichiana and the highly preferred U pumila were more suitable for feeding and reproduction. Suitability had no significant effect on male and female longevity. The least suitable species of U. changii, U. lanceaefolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis show promise for future elm breeding programs.

Animals↗
PubMed2001

Preference of temperate Chinese elms (Ulmus spp.) for the adult Japanese beetle (Coleoptera: Scarabaeidae).

Trees of newly acquired Ulmus species originating from the temperate regions of China and growing at The Morton Arboretum, Lisle, IL, were evaluated in no-choice and multiple-choice laboratory bioassays and cage-studies for feeding preference for adults of the Japanese beetle, Popillia japonica Newman. Ulmus lanceaefolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis were less preferred for feeding by adult Japanese beetles. No-choice, multiple-choice, and cage feeding studies revealed that Ulmus wallichiana was moderately preferred, and U. procera and U. americana were highly preferred for feeding. Dry fecal pellet weights were strongly correlated with the percent of leaf tissue removed. Feeding preference in the multiple-choice study was strongly correlated with feeding preference in the cage study and in the no-choice study. Likewise, adult feeding preference in the cage study was strongly correlated with preference in the multiple-choice and no-choice studies. The less preferred species of U. lanceafolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis show promise for future elm breeding programs.

Animals↗
PubMed2006

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China.

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pygmaeum, L. sclerotii var. sclerotii, L. sclerotii var. sichuanense, L. subpygmeaum, L. tenuissimum, L. virgineum and L. willisii are reported, whose main characteristics are given in a formula of the described species, some of which are discussed below.

Ascomycota↗
PubMed2000

Trichinella murrelli n. sp: etiological agent of sylvatic trichinellosis in temperate areas of North America.

Trichinella T5, collected from sylvatic carnivores in North America, was identified previously as a different phenotype of Trichinella, with an uncertain taxonomic level due to the availability of only 2 isolates. Cross-breeding experiments carried out with single female and male larvae of 2 strains of Trichinella T5, with single female and male larvae of 2 strains of Trichinella spiralis, Trichinella nativa, Trichinella britovi, Trichinella pseudospiralis, Trichinella nelsoni, and Trichinella T6, showed a reproductive isolation of Trichinella T5. Viable offspring were obtained only when a female of Trichinella T5 was crossed with a male of T. britovi, but not vice versa. Furthermore, the analysis of biological, biochemical, and molecular data of 32 isolates collected from sylvatic animals in the Nearctic region and identified as Trichinella T5 permitted its reassessment at the species level. Trichinella murrelli n. sp. is characterized by the following: distribution in temperate areas of the Nearctic region; newborn larvae production in vitro of 29-36/72 hr; nurse cell development time between 24 and 70 days postinfection; reproductive capacity index in Swiss mice 1.2-9.5, in wild mice 29.5-159.8, in rats 0.7-2.4, and in pigs 0.03-0.0004; no resistance to freezing; ribosomal DNA fragments of 7.2 kb and/or 11.4 kb, plus 2.2 kb and 1.8 kb present after Dra I digested DNA when probed with total T. spiralis RNA; a specific amplicon of 179 bp after polymerase chain reaction (PCR) amplification with the primer set SB147G; a specific fragment of 1,600 bp after PCR amplification with the primer set Ts43CA and Hhb I digestion; long incubation period; and moderate to severe pathogenicity for humans. The new species is most similar to T. britovi, though it differs from T. britovi in the pattern of 2 allozymes, in the patterns of major ribosomal DNA and PCR-restriction fragment length polymorphism fragments, and in geographical distribution.

Animals↗
PubMed2006

Jellyfish aggregations and leatherback turtle foraging patterns in a temperate coastal environment.

Leatherback turtles (Dermochelys coriacea) are obligate predators of gelatinous zooplankton. However, the spatial relationship between predator and prey remains poorly understood beyond sporadic and localized reports. To examine how jellyfish (Phylum Cnidaria: Orders Semaeostomeae and Rhizostomeae) might drive the broad-scale distribution of this wide ranging species, we employed aerial surveys to map jellyfish throughout a temperate coastal shelf area bordering the northeast Atlantic. Previously unknown, consistent aggregations of Rhizostoma octopus extending over tens of square kilometers were identified in distinct coastal "hotspots" during consecutive years (2003-2005). Examination of retrospective sightings data (>50 yr) suggested that 22.5% of leatherback distribution could be explained by these hotspots, with the inference that these coastal features may be sufficiently consistent in space and time to drive long-term foraging associations.

Animals↗
PubMed2005

Can constructed wetlands reduce the diffuse phosphorus loads to eutrophic water in cold temperate regions?

Construction of wetlands is a possible supplement to best management practices (BMP) at the field level to mitigate phosphorus (P) pollution from agricultural areas. In this paper, annual results from 17 intensively studied wetlands in the cold temperate or boreal climatic zone are reported and analyzed. Surface areas varied from 0.007 to 8.7% of the catchment area. The average total phosphorus (TP) retention varied from 1 to 88%, and the dissolved reactive phosphorus (DRP) retention from -19 to 89%. Retention varied substantially from site to site, indicating the existence of site-specific factors in the catchment and wetlands that influenced the P removal. Factors important for P retention in wetlands were evaluated through multiple statistical analyses by dividing P into two fractions: particulate phosphorus (PP) and DRP. Both relative (%) PP and DRP retention increased with wetland surface area. However, PP retention was not as sensitive as DRP in terms of wetland size and retention: specific PP retention (gram P retention per m(2) and year) decreased as wetland area (A(w)) increased, suggesting the existence of a site-specific optimal wetland to catchment area (A(c)) ratio. Particulate P retention decreased with increasing DRP to TP ratio, while the opposite was found for DRP. Dissolved reactive P retention was higher in new than in old wetlands, while increasing age did not influence PP retention negatively. Effective BMP in the catchment is important to keep the P loss low, because the outlet concentration of P from wetlands is often positively correlated to the input concentration. However, wetlands act as the last buffer in a catchment, since the retention often increases as the P concentration in streams increases.

Climate↗
PubMed2006

Soil carbon and nitrogen storage in response to fire in a temperate mixed-grass savanna.

Vegetation fires may alter the quantity and quality of organic matter inputs to soil, rates of organic matter decay, and environmental factors that influence those processes. However, few studies have evaluated the impacts of this land management technique on soil organic carbon (SOC) and total N in grasslands and savannas. We evaluated the impact of repeated fires and their season of occurrence on SOC and total N storage in a temperate mixed-grass-mesquite savanna where fire is used to control woody plant encroachment. Four fire treatments varying in season of occurrence were examined: summer only (SF), winter only (WF), alternate summer and winter fires (SWF), and unburned controls. In each treatment, soils were sampled to 1 m under three vegetation types: C3 grasses, C4 grasses, and mesquite trees. The SOC storage at 0 to 20 cm was significantly greater in SF (2693 g C m(-2)) and SWF (2708 g C m(-2)) compared to WF (2446 g C m(-2)) and controls (2445 g C m(-2)). The SWF treatment also increased soil total N (271 g N m(-2)) relative to all other treatments (228-244 g N m(-2)) at 0 to 20 cm. Fire had no effect on SOC or total N at depths of > 20 cm. Vegetation type had no significant influence on SOC or total N stocks. The delta13C value of SOC was not affected by fire, but increased from -21 per thousand at 0 to 10 cm to -15 per thousand at depths of > 20 cm indicating that all treatments were once dominated by C4 grasses before woody plant encroachment during the past century. These results have implications for scientists, land managers, and policymakers who are now evaluating the potential for land uses to alter ecosystem C storage and influence atmospheric CO2 concentrations and global climate.

Carbon↗
PubMed2003

Early development and acquisition of Zooxanthellae in the temperate symbiotic sea anemone Anthopleura ballii (Cocks).

The ova of Anthopleura ballii become infected with zooxanthellae (endosymbiotic dinoflagellates) of maternal origin just prior to spawning. After fertilization, the zygotes undergo radial, holoblastic cleavage, and then gastrulate by invagination to form ciliated planulae. Because the zooxanthellae are localized on one side of the ovum-and later, within the blastomeres at one end of the embryo-invagination leads to the zooxanthellae being restricted to the planular endoderm and hence to the gastrodermal cells of the adult anemone. We propose that maternal inheritance of zooxanthellae plays an important part in the success of these temperate sea anemones, which live in regions where potential sources of zooxanthellae are scarce.

Animals↗
PubMed1998

Integration of the temperate phage phiU into the putative tRNA gene on the chromosome of its host Rhizobium leguminosarum biovar trifolii.

The plasmid pCI6, carrying the attP site of the temperate phage phiU, integrates into the attB site on the chromosome of Rhizobium leguminosarum biovar trifolii strain 4S. The 4 kb EcoRI-HindIII region of pCI6 involved in site-specific integration was subcloned as the attP fragment of phage phiU and sequenced. The attL fragment, one of the new DNA junctions generated from the insertion of pCI6 into the chromosome of the host Rhizobium, was used as a hybridization probe for isolation of the attB fragment of strain 4S. The nucleotide sequence of the 2 kb PstI fragment of strain 4S, which hybridized with the attL fragment, was decided and compared with that of the attP fragment. A 53 bp common sequence was expected to be the core sequence of site-specific integration between phage phiU and strain 4S. One of the ORFs on the attP fragment, which was located adjacent to the core sequence, had structural homology to the integrase family. However, the attB fragment showed high homology with the tRNA genes of Agrobacterium tumefaciens and E. coli. A 47 bp sequence of the 53 bp core sequence overlapped with this tRNA-like sequence. This indicates that the target site of phage phiU integration is the putative tRNA gene on the chromosome of the Rhizobium host.

Journal Article↗
PubMed1975

Psychophysical preference for harmonized musical passages in the Just and Equal Tempered systems.

Preferences were obtained from both experienced and untrained Ss concerning musical passages presented in both Just (natural) and Equal Tempered (synthetic) tuning systems. While a significant preference for Just tonation was recorded for all Ss, no significant difference for preference was found between moderately experienced musicians and non-performers. Boys showed a greater, and significant, preference for Just tuning than did girls.

Adolescent↗
PubMed2001

The amino acid profiles of the whole plant and of four plant residues from temperate and tropical forages.

This study compared the amino acid (AA) profile of five residues (original forage, borate-phosphate buffer residue (BPR), neutral detergent fiber residue with (NDF+) and without (NDF-) sodium sulfite, and acid detergent fiber residue (ADF). Fourteen grasses and legumes from tropical and temperate regions were used in this study. The use of sodium sulfite did not affect the NDF concentration, but the NDF insoluble protein was lower (P < 0.05) in the NDF+ than in the NDF- (3.9 vs 4.5% DM, respectively). For all of the amino acids tested, the amino acid content, expressed as a percentage of CP, was lower in the ADF residue than in the original forage. There were no differences in the amino acid concentrations of the NDF- and NDF+ extracts (P > 0.05). Only in the case of methionine was there a difference in the amount of amino acid when the original forage was compared with the BPR (1.84 vs 1.45 % CP). When the AA profile of each residue was corrected for the AA content of the ADF, no difference was observed between the AA profile of the original forage and of the BPR (P > 0.05). Similar to the result without correction for the amino acids in ADF, the AA profiles of the NDF+ and NDF- fractions were similar (P > 0.05). From this result, we infer that the sodium sulfite had similar effects on all AA in the NDF residue that we tested. There were differences in amino acid concentrations in the original forage and the NDF residues for several amino acids (Met, Cys, Lys, Thr, Arg, Ile, Leu, and Phe) (P < 0.05). When the amino acid values of the original forage and the BPR were used with animal data in the Cornell Net Carbohydrate and Protein System model, few differences in animal predicted performance were evident. These findings suggest that the AA profile of the original forage can be used to predict the AA profile of the undegraded intake protein instead of using the borate-phosphate buffer residue for amino acid analyses. This would simplify obtaining feed amino acid values for use in the Cornell Net Carbohydrate and Protein System.

Amino Acids↗