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Helena J Bailes Wayne L Davies Ann EO Trezise Shaun P Collin 《BMC evolutionary biology》2007,7(1):200
Background
One of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. Interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. The Australian lungfish Neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods. 相似文献2.
EO Ogueji CD Nwani SC Iheanacho CE Mbah CO Okeke A Yaji 《African Journal of Aquatic Science》2018,43(3):293-303
Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled. 相似文献
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BRANT C. FAIRCLOTH ALLISON REID TERESA VALENTINE SOO HYUNG EO THERON M. TERHUNE TRAVIS C. GLENN WILLIAM E. PALMER CAMPBELL JOSEPH NAIRN JOHN P. CARROLL 《Molecular ecology resources》2005,5(2):387-389
We describe primers and polymerase chain reaction (PCR) conditions to amplify four dinucleotide, one trinucleotide, and three tetranucleotide microsatellite DNA loci from the bobcat (Lynx rufus). The primers were tested on 22 individuals collected from a population located within southwestern Georgia (USA). The primer pairs developed in this study yielded an average of 7.4 alleles per locus (range four to 10), an average observed heterozygosity of 0.60 (range 0.40 to 0.76), and an average polymorphic information content of 0.70 (range 0.51 to 0.78). 相似文献
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The trophic state of Lake Baringo and factors that could be limiting the development of algal biomass in it were investigated during one wet/dry hydrological cycle in 2014–2015. Water samples were analysed for dissolved inorganic nutrients, including , and , total phosphorus and Chlorophyll a. Light attenuation was estimated using Secchi depth. The trophic state was determined using Carlson trophic state indices (CTSI). Deviations in CTSI, nutrient ratios and ambient nutrient concentrations were used to identify factors limiting phytoplankton growth. The mean values measured for Secchi depth, nitrate, total phosphorus and Chlorophyll a showed significant seasonal variation (p < 0.05). Based on the Carlson trophic state index, the results show that Lake Baringo is eutrophic. However, the lake is also experiencing phosphorus limitation and poor light penetration, because of high turbidity, which is more pronounced during the wet season. 相似文献
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Lifetable demography and reproductive traits of a Kenyan strain of the rotifer Brachionus angularis were investigated using individual and small batch culture approaches. The rotifer was identified morphologically before conducting studies at 20, 25 and 30 °C, using Chlorella vulgaris at 2.5 × 105 to 2.5 × 107 cells ml–1. The rotifers were highly fecund, producing 2.11 ± 0.07 offspring female–1 day–1 and reproductive, producing 8.43 ± 0.24 offspring female–1 at 25 °C with 2.5 × 106 algal cells ml–1. The highest intrinsic rate of natural increase (0.74 ± 0.02 d–1), specific population growth rate (0.49 ± 0.01), longest life expectancy at hatching (12.41 ± 0.28 d) and shortest generation time (2.87 ± 0.03 d) also occurred at 25 °C with 2.5 × 106 algal cells ml–1. The duration of hatching to first spawning was shortest (2.86 ± 0.21 h) at 30 °C with 2.5 × 107 algal cells ml–1 and longest (8.83 ± 0.39 h) at 20 °C with 2.5 × 105 algal cells ml–1. The highest population density (255.7 ± 12.6 ind. ml–1) was realised at 25 °C with 2.5 × 106 cells ml–1 on Day 8, whereas the lowest population density (122.0 ± 3.6 ind. ml–1) was realised at 20 °C with 2.5 × 105 cells ml–1 on Day 8. The lorica length and width of the Kenyan strain of B. angularis are 85.6 ± 3.1 µm and 75.4 ± 3.6 µm, respectively. The rotifer optimally reproduces at 25 °C when fed with 2.5 × 106 algal cells ml–1. 相似文献
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This article presents a fossil diatom-based, semi-quantitative reconstruction of water level fluctuations for Lake Baringo over the past 200 years as a consequence of climatic variations. A 285 cm long sediment core sample was collected using a Rod-Operated Single-drive Stationary Piston corer. Lake level was inferred using indices based on the proportion of planktonic to benthic diatom taxa (P/B ratio). The sediment archive presented distinct zones dominated by planktonic and benthic diatom flora. An initial transgression in the early 19th century was characterised as a shallow water environment dominated by planktonic Aulacoseira spp. This was a response to extreme drought during the late 18th to early 19th century. Mid-19th century was defined by a high lake stand. The late 19th to early 20th centuries experienced low water level following the widely documented aridity at the time. The mid-20th century was marked by a spectacular rise in water level that coincided with remarkably wet years during the early 1960s and late 1970s. The first decade of the 21st century witnessed widespread changes in water level. The proxy records show that lake ramping and drawdown over the years follow approximately 50-year climatic cycles. 相似文献
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Copper sulfate can cause different pathologies in different organ systems during development. We determined the effects of toxic levels of copper sulfate on brain development in term Hubbard broiler chicks using stereological and biochemical analyses. Hubbard broiler chicken eggs were divided into three groups: controls with no treatment, sham-treated animals and an experimental group. On day 1, 0.1 ml saline was injected into the air chambers of the sham and experimental groups. The experimental group received also 50 μg copper sulfate. At term (day 21), all chick brains were removed and their volumes were determined using the Cavalieri volume estimation. Parallel biochemical analyses were carried out for glutathione and malondialdehyde levels in the brain tissues as indicators of oxidative damage. With copper treatment, the mean brain volume (8079 μm3) was significantly decreased compared to both the control (10075 μm3) and sham (9547 μm3) groups. Copper treatment (143.8 nmol/g tissue) showed significantly decreased malondialdehyde levels compared to the control (293.6 nmol/g tissue) and sham groups (268.8 nmol/g tissue). Copper treatment (404.5 nmol/g tissue) showed significantly increased malondialdehyde levels compared to the control (158.6 nmol/g tissue) and sham (142.8 nmol/g tissue) groups. The morphological and biochemical parameters we measured demonstrated that in term Hubbard broiler chicks, toxic levels of copper sulfate cause developmental and oxidative brain damage. 相似文献
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Sonia Maria Raboni Guilherme Augusto Costa Damasio Carla EO Ferreira Luciane A Pereira Meri B Nogueira Luine R Vidal Cristina R Cruz Sergio M Almeida 《Memórias do Instituto Oswaldo Cruz》2014,109(4):428-435
Viral acute gastroenteritis (AG) is a significant cause of hospitalisation in
children younger than five years. Group A rotavirus (RVA) is responsible for 30% of
these cases. Following the introduction of RVA immunisation in Brazil in 2006, a
decreased circulation of this virus has been observed. However, AG remains an
important cause of hospitalisation of paediatric patients and only limited data are
available regarding the role of other enteric viruses in these cases. We conducted a
prospective study of paediatric patients hospitalised for AG. Stool samples were
collected to investigate human adenovirus (HAdV), RVA, norovirus (NoV) and astrovirus
(AstV). NoV typing was performed by nucleotide sequencing and phylogenetic analysis.
From the 225 samples tested, 60 (26%) were positive for at least one viral agent.
HAdV, NoV, RVA and AstV were detected in 16%, 8%, 6% and 0% of the samples,
respectively. Mixed infections were found in nine patients: HAdV/RVA (5), HAdV/NoV
(3) and HAdV/NoV/RVA (1). The frequency of fever and lymphocytosis was significantly
higher in virus-infected patients. Phylogenetic analysis of NoV indicated that all of
these viruses belonged to genotype GII.4. The significant frequency of these
pathogens in patients with AG highlights the need to routinely implement laboratory
investigations. 相似文献
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