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181.
Petter Larsson John E. Brittain Leif Lien Albert Lillehammer Karl Tangen 《Ecography》1978,1(2-3):304-320
The Norwegian subalpine lake. Øvre Heimdalsvatn, has a surface area of 0.78 km2 and a maximum depth of 13 m. It is ice-covered for 7.5–8 months, has a marked spring spate and a mean annual renewal period of about two months. The water is poor in electrolytes. Intensive studies have been made by an interdisciplinary team of the lake's physical and chemical properties, primary production and secondary production under the auspices of IBP/PF from 1969 to 1973, Allochthonous material accounted for 1/3 of utilized plant input. The major lake predator, the brown trout, fed largely on benthic organisms and did not exploit the zooplankton biomass. On account of the long period of ice cover and the rapid rise in temperature after ice break, many organisms (both planktonic and benthic) showed synchronous development. Abiotic conditions, such as the nature of the spring spate and the temperature rise, strongly affect species and community development. 相似文献
182.
Synchronization and synchronous growth of a cell wall-less mutant of Chlamydomonas reinhardii have been described. The following growth conditions were used: A modified Sueokas' high salt minimal medium, 1410 h light-dark cycle, growth temperature 30°C, light intensity 12–18 Klux and dilution of the culture at the end of the dark to a constant cell density of 1.0·106 cells/ml. The time course of increase and distribution of cell volume, cytoplasmic and nuclear division, release of motile cells after the division period and accumulation of DNA, RNA and protein are reported. These mutant cells did not make any sporangium in which the dividing cells were kept as a unit inside a mother cell wall. However, they usually adhered during the period of division, thus making clumps containing 2, 4 and 8 cells. Several of these cell clumps dissolved releasing either single or couples of 2 and 4 cells. After the end of division the cells became flagellated and motile and thereby releasing themselves from the aggregate.Non-Standard Abbreviations AWV
average weighed cell volume
- MM
minimal medium
- HSM
high salt medium
- TCA
trichloroacetic acid 相似文献
183.
Yu-Lin Ko Wen-Pin Lien Jin-Jer Chen Chen-Wen Wu Tang-K. Tang Choong-Chin Liew 《Human genetics》1992,89(6):597-601
Summary To understand the molecular basis of familial hypertrophic cardiomyopathy (FHC) in the Chinese population, a family with FHC was investigated. Nineteen family members who were 16 years of age or older were examined by M-mode or two-dimensional echocardiography. Eight members were diagnosed to be affected echocardiographically or clinically. Lymphocytes isolated from 20 family members were successfully transformed into permanent lymphoblastoid cell lines by Epstein-Barr virus. Three genomic DNA probes (CRI-L436, CRI-L329, and pSC14) that were derived from chromosome 14q1 loci and demonstrated to be linked closely to FHC were used to probe this family. Using the techniques of restriction fragment length polymorphism (RFLP) and linkage analysis, the probe CRI-L436, which recognized locus D14S26, was found informative in this family. The lod scores were -2.0 at = 0.025 and -1.49 at = 0.05. Thus, there was no evidence of linkage between the locus D14S26 and the gene for FHC in the pedigree studied. In addition, polymerase chain reaction (PCR) amplification did not indicate a mutation on exon 13 of the cardiac myosin heavy chain gene as previously reported. Our data suggest that FHC is a genetically heterogeneous disease. 相似文献
184.
Hydrogen production by cell-free extracts of Chlamydomonas reinhardtii is stimulated by anions when methyl viologen, reduced by dithionite, is used as the electron donor to hydrogenase. The increasing effectiveness of various anions closely follows their position in the Hofmeister chaotropic sequence. The most stimulatory anion tested, I?, gives a six-fold increase in activity at a concentration of 0.5 n. The Km of the enzyme for methyl viologen is not affected by anions, while the V is greatly increased. H2 oxidation coupled to methyl viologen reduction is also greatly stimulated by anions. However, when reduced ferredoxin is used as the electron donor to hydrogenase, there is a very strong inhibition of H2 production by salts. In this case, the V of the enzyme is unaffected, but there is a large increase in the Km of the enzyme for ferredoxin. The most inhibitory salt tested, KI, decreases hydrogenase activity by 93% at a concentration of 0.2 n. 相似文献
185.
Huey-En Tzeng Syuan-Ling Lin Louis Anoop Thadevoos Ming-Yu Lien Wei-Hung Yang Chih-Yuan Ko Chih-Yang Lin Yu-Wen Huang Ju-Fang Liu Yi-Chin Fong Hsien-Te Chen Chih-Hsin Tang 《Cell death & disease》2021,12(12)
Chondrosarcoma is a malignancy of soft tissue and bone that has a high propensity to metastasize to distant organs. Nerve growth factor (NGF) is critical for neuronal cell growth, apoptosis, and differentiation, and also appears to promote the progression and metastasis of several different types of tumors, although the effects of NGF upon chondrosarcoma mechanisms are not very clear. We report that NGF facilitates lysyl oxidase (LOX)-dependent cellular migration and invasion in human chondrosarcoma cells, and that NGF overexpression enhances lung metastasis in a mouse model of chondrosarcoma. NGF-induced stimulation of LOX production and cell motility occurs through the inhibition of miR-149-5p expression, which was reversed by PI3K, Akt, and mTOR inhibitors and their respective short interfering RNAs. Notably, levels of NGF and LOX expression correlated with tumor stage in human chondrosarcoma samples. Thus, NGF appears to be a worthwhile therapeutic target for metastatic chondrosarcoma.Subject terms: Bone cancer, Cell invasion 相似文献
186.
H. Nilsen H. G. Olsen B. Hayes T. Nome E. Sehested M. Svendsen T. H. E. Meuwissen S. Lien 《Animal genetics》2009,40(5):701-712
Quantitative trait loci affecting clinical mastitis were detected and fine mapped to a narrow region on bovine chromosome 6 in the Norwegian Red cattle population. The region includes the casein gene cluster and several candidate genes thought to influence clinical mastitis. The most significant results were found for SNPs within the Mucin 7 gene. This gene encodes an antimicrobial peptide and constitutes part of the first line of defence for the mucosal immune system. Detection of long haplotypes extending several Mb may indicate that artificial selection has influenced the haplotype structures in the region. A search for selection sweeps supports this observation and coincides with association results found both by single SNP and haplotype analyses. Our analyses identified haplotypes carrying quantitative trait loci alleles associated with high protein yield and simultaneously fewer incidences of clinical mastitis. The fact that such haplotypes are found in relative high frequencies in Norwegian Red may reflect the combined breeding goal that is characterized by selection for both milk production and disease resistance. The identification of these haplotypes raises the possibility of overcoming the unfavourable genetic correlation between these traits through haplotype-assisted selection. 相似文献
187.
Maldin B Inglesby TV Nuzzo JB Lien O Gronvall GK Toner E O'Toole T 《Biosecurity and bioterrorism : biodefense strategy, practice, and science》2005,3(4):363-367
Bulls, Bears, and Birds: Preparing the Financial Industry for an Avian Influenza Pandemic was a half day symposium on avian influenza for senior leaders and decision makers from the financial sector with responsibility for business continuity, health, and security. The event brought together experts and leaders from the medical, public health, business continuity, and financial communities to appraise financial industry leaders on the threat of avian influenza and to offer suggestions regarding what the financial industry could do to prepare and respond. 相似文献
188.
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190.
Jackson JG Janszen DB Lonnerdal B Lien EL Pramuk KP Kuhlman CF 《The Journal of nutritional biochemistry》2004,15(9):517-521
Alpha-lactalbumin, a 14-kD protein, plays a central biochemical role in the mammary gland as the regulatory subunit of lactose synthase, and also plays a nutritional role for the rapidly growing neonate as the protein in highest concentration in human milk. The current study was undertaken to better characterize alpha-lactalbumin concentrations in human milk from a variety of countries. Mature human milk (lactation duration > or =1 month) was collected from at least 50 women from nine different countries on five continents. Alpha-lactalbumin concentration was determined by HPLC. The mean +/- SD for 452 samples was 2.44 +/- 0.64 g/L. The mean value of the samples from the United States was significantly higher than that from any other country, and the mean in Mexico was significantly lower than that from every country except China and Canada. Alpha-lactalbumin concentration decreased with increasing duration of lactation and was positively correlated with total nitrogen. On average, alpha-lactalbumin contributed 16% of the total nitrogen content of human milk and consequently an important part of the amino acid content. 相似文献