In order to define the role of nitric oxide (NO) in feline mammary tumours, the expression of endothelial or inducible nitric oxide synthase (e/iNOS) and vascular endothelial growth factor (VEGF), and their relationship with angiogenesis, was investigated in 23 feline mammary tumours (two hyperplastic, 19 adenocarcinoma, one osteosarcoma and one squamous cell carcinoma) by immunohistochemistry. Tumour angiogenesis was assessed by CD31 immunostaining and was expressed as microvessel density (MVD). In general, iNOS immunoreactivity was localised in tumour cells and occasionally in stromal myofibroblasts, whereas eNOS and VEGF were localised in the cytoplasm of tumour epithelial cells and endothelium. In malignancy, expression of iNOS increased from well- to less-differentiated phenotypes (Grades 1-3) and was significantly higher in G3 and G2 when compared with G1 cases. However, increasing eNOS expression was limited only in hyperplastic lesions and showed no significant changes among the grades. In addition, expression of iNOS was positively correlated with VEGF and MVD in feline mammary tumours and both measures were significantly greater in less differentiated phenotypes (P<0.05). In conclusion, the expression of NOS isoforms in feline mammary tumours depended on tumour grade, and the positive correlations between iNOS and angiogenic markers suggests that iNOS synthesised by tumour cells promotes tumour growth. Thus, iNOS can be used as an important immunohistochemical marker to determine the degree of malignancy and prognosis of feline mammary carcinoma. 相似文献
Insects respond to changes in microhabitat caused by canopy disturbance, and thus can be used to examine the ecological impacts of harvesting. Single-tree selection harvesting is the most common silvicultural system used to emulate local small-scale natural disturbance and maintain uneven-aged forest structure in temperate forests. Here, we test for differences in richness, abundance, and composition of hymenopteran and saproxylic insect assemblages at four different taxon levels (selected insect orders; and all hymenopteran families, and braconid subfamilies and morphospecies) between the canopy and understory of unharvested and single-tree selection harvested sites in a northern temperate forest from central Canada. Harvesting had no effect on insect assemblage richness, composition or abundance at the three highest taxon levels (order, family and subfamily). Similarly, richness and abundance at the lowest-taxon level (braconid morphospecies) were similar, although composition differed slightly between unharvested and harvested stands. Insect assemblages were vertically stratified, with generally higher abundance (for Diptera, Hymenoptera, some hymenopteran families and braconid subfamilies) and richness (for braconid morphospecies) in the understory than the canopy. In particular, composition of the braconid morphospecies assemblage showed relatively low similarity between the understory and canopy. Single-tree selection harvesting appears to influ-ence wood-associated insect taxa only subtly through small changes in community composition at the lowest taxon level, and thus is recommended as a conservative approach for managing these northern temperate forests. 相似文献
Paddy and Water Environment - Repairs of concrete irrigation channels in Japan are guided to a large extent by the degree to which their walls have degraded over decades of use. Current methods of... 相似文献
Humic substances, which are integral components of total organic carbon (TOC), influence soil quality. The study aimed to investigate whether humic and non-humic fractions exhibit early, consistent, and measurable changes and affect TOC sensitivity and storage in a tropical sandy loam soils amended with corn cob biochar.
Materials and methods
There were four treatments with four replicates established in a randomized complete block design. Composite soil samples were taken from plots without biochar (CT), from plots incorporated with 15 t biochar ha?1 (BC-15), and 30 t biochar ha?1 without or with phosphate fertilizer (BC-30 and BC-30+P). The TOC, and humin, humic acid (HA), and fulvic acid (HA) fractions of soil organic carbon were determined for each treatment. The optical densities (400–700 nm) were measured on the soil-free extracts by spectrophotometry; the densities measured at 465 and 665 nm were used to calculate the E465/E665 ratios.
Results and discussion
The BC-30 and BC-30+P plots recorded the highest TOC, humin, humic acid (HA), and fulvic acid (FA) contents with respect to the lowest in the CT. The total exchangeable carbon stratification was significantly higher in all the biochar-treated plots relative to the CT. Spectral analysis showed higher values of E465/E665 (5.02 and 5.15) in the CT and BC-15-treated soils, respectively, compared with the BC-30 and BC-30+P-amended soils with E465/E665 ratios of 2.76 and 2.98, respectively.
Conclusions
Corn cob biochar applied to a tropical sandy loam:
? increased the concentrations of HA and FA and led to increased stratification of TOC, with a stronger effect on HA compared with FA;
? significantly lowered E465/E665 at the high biochar application rate of 30 t ha?1, implying the dominance of high molecular weight humic acid-like substances, and increased degree of aromaticity of the TOC.
ABSTRACT1. The aim of this study was to explore genetic diversity and possible origin of Bangladeshi (BD) native chickens. The complete mtDNA D-loop region was sequenced in 60 chickens representing five populations; naked neck, full feathered, Aseel, Hilly and autosomal dwarf. The 61 reference sequences representing different domestic chicken clades in China, India, Laos, Indonesia, Myanmar, and other Eurasian regions were included. The mtDNA D-loop sequence polymorphism and maternal origin of five BD populations were analysed.2. A total of 35 polymorphic sites, and 21 haplotypes were detected in 60 mtDNA D-loop sequences. The haplotype and nucleotide diversity of the five populations were 0.921 ± 0.018 and 0.0061 ± 0.0019, respectively. Both mtDNA network and phylogenetic analysis indicated four clades (four haplogroups) in BD populations (21 haplotypes) along with 61 reference haplotypes. Clade E contained the most individuals (20) and haplotypes (11) of BD chickens, followed by clade D (17, 6), clade C (12, 2) and clade F (11, 2), respectively.3. The higher number of unique haplotypes found in Yunnan, China, suggested that the origin of BD chickens was in this region. The haplotypes from different haplogroups were introduced in Bangladeshi chickens from India, China and Myanmar. The phylogenetic tree showed a close relationship of BD chickens with the clusters from India, China, Myanmar and Laos, and indicated the dispersion of BD chickens from these sources. The phylogenetic information revealed high genetic diversity of BD chickens because of their origin from different lineages with high genetic variation and distance, which was determined from four cluster and neighbour-joining trees.4. In conclusion, BD populations had high genetic diversity. The mtDNA network profiles and phylogenetic trees showed multiple maternal origins of BD chickens from India, China, Myanmar and Laos. 相似文献
Precipitation was collected on an event basis from July 1994 to August 1995 at towns around the capital Dhaka of Bangladesh. The major chemical components were determined by atomic absorption spectrophotometry, UV-Visible spectrophotometry and ion selective electrode method. The concentrations of nitrate and sulphate were found to be below the minimum detection limit of 1.0 mg L- 1; the concentrations of Cl-, Na+, K+, Ca+2, Mg+2 and NH4+ ranged from <1.0–3.03, 0.14–1.70, 0.04–0.37, 0.04–1.30, <0.02–0.20 and <0.10–2.33 mg L-1, respectively. The values of pH and conductivity ranged from 4.80–6.74 and 3.3–37.5 μS cm-1, respectively. 相似文献
Volatile organic compounds in the ambient air were measured at four locations in Rousse, Bulgaria for a one year period. A gas chromatograph/mass spectrometer equipped with a cryogenic concentrator was used to analyse the air samples. Forty one compounds (aromatic hydrocarbons and halogen-derivatives of aliphatic and aromatic hydrocarbons) were analysed by EPA method TO-14. Aromatic hydrocarbons, benzene, toluene, styrene, isomers of xylene and isomers of trimethyl benzene were the most frequently occurring pollutants. Styrene, isomers of xylene and isomers of trimethyl benzene frequently exceeded the concentration limits. Among the halogen derivatives, the concentration of chloroform was always very high. A concept called ‘degree of pollution’ was proposed to clarify the contribution of each pollutant to the total air-pollution. Suggestions were made on the need to introduce an integral tolerance parameter to describe the total impact on air-pollution. 相似文献
Soft‐shell crab, a newly moulted crab having non‐calcified and hydrated soft exoskeleton, farming has been increasing tremendously in recent years throughout the world due to its high market price and consumer preferences. However, high aggressiveness and cannibalistic behaviour of mud crab limit its culture to an individual chamber system which ultimately makes the soft‐shell mud crab farming space and labour‐intensive. Therefore, the aim of this study was to improve the efficiency of soft‐shell crab production by autotomy of the claw and/or walking legs to reduce the moulting duration and intensify the culture system through double stocking in the existing individual chamber culture system. To achieve our objectives, a series of experiment were conducted at both indoor and on‐farm levels by removing the claw and/or walking legs of Scylla olivacea for two consecutive moulting cycles. Results showed that both claw ablation significantly (p < .01) shortened the moulting duration and increased the carapace width, weight gain, specific growth rate, feeding efficiency and yield parameter compared to the non‐ablated crabs more prominently at 1st moulting than the 2nd moulting in both indoor and on‐farm trials. Ablation of all walking legs while keeping the claw intact did not significantly influence (p > .05) the moulting duration and carapace width, but significantly (p < .01) improved the specific growth rate, weight gain, feeding efficiency and yield parameters at 1st moulting compared to the non‐ablation and unilateral three walking leg ablation groups. However, ablation of all appendages (both claw and walking legs) showed significant (p < .01) improvements of carapace width, weight gain, specific growth rate, feeding efficiency and yield parameters, and shortened the moulting duration up to 23 days from 34 days during 1st moulting and up to 27 days from 40 days at 2nd moulting. The survivals of different autotomized mud crabs were statistically non‐significant (p > .05) to the non‐autotomized crabs in various indoor and on‐farm trials. Besides improving the production performances, ablation of bilateral claw and all appendages allowed to double the stocking density in the existing individual chamber‐based soft‐shell crab farming that enhanced the production about threefold higher than the existing individual chamber‐based culture system. Finally, our results suggest that autotomy could be a promising technology for the commercial farming of soft‐shell mud crab in near future. 相似文献
This study investigated the effects of sodium alginate supplementation on gut microbiota composition, health parameters, growth performances and growth‐related gene expression of Malaysian mahseer. Five test diets were formulated by supplementing 0%, 0.1%, 0.2%, 0.4% and 0.8% sodium alginate. Triplicate groups of juvenile Tor tambroides (2.19 ± 0.05 g) were stocked in 15 aquaria (20 individuals per aquarium) and fed at 3.0% body weight per day for 60 days. PCoA and UPGMA analysis showed that gut bacterial community were more convergence in higher sodium alginate‐supplemented diets. The percentage of Porphyromonadaceae, Bacteroides, Plesiomonas and Shewanella were substantially higher and Aeromonas, Entomoplasmatales and Prevotellaceae were drastically lower in higher sodium alginate (0.2%–0.8%) diets. Sodium alginate supplementation (≥0.2%) significantly improved the haematocrit value and respiratory burst activity of T. tambroides. Growth performances and feed utilization were significantly higher in 0.2%–0.4% sodium alginate‐supplemented diets. The increased growth rate of T. tambroides was governed by both hyperplastic and hypertrophic muscle growth. Real‐time PCR data demonstrated that most of the growth‐related genes were significantly upregulated in 0.2%–0.4% sodium alginate‐supplemented diet. Finally, it can be concluded that sodium alginate should be supplemented at 2 g/kg in practical fish feed formulation. 相似文献