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Annelies J. Veraart Anna M. Romaní Elisabet Tornés Sergi Sabater 《Journal of phycology》2008,44(3):564-572
Nutrient input in streams alters the density and species composition of attached algal communities in open systems. However, in forested streams, the light reaching the streambed (rather than the local nutrient levels) may limit the growth of these communities. A nutrient‐enrichment experiment in a forested oligotrophic stream was performed to test the hypothesis that nutrient addition has only minor effects on the community composition of attached algae and cyanobacteria under light limitation. Moderate nutrient addition consisted of increasing basal phosphorus (P) concentrations 3‐fold and basal nitrogen (N) concentrations 2‐fold. Two upstream control reaches were compared to a downstream reach before and after nutrient addition. Nutrients were added continuously to the downstream reach for 1 year. Algal biofilms growing on ceramic tiles were sampled and identified for more than a year before nutrient addition to 12 months after. Diatoms were the most abundant taxonomic group in the three stream reaches. Nutrient enrichment caused significant variations in the composition of the diatom community. While some taxa showed significant decreases (e.g., Achnanthes minutissima, Gomphonema angustum), increases for other taxa (such as Rhoicosphenia abbreviata and Amphora ovalis) were detected in the enriched reach (for taxonomic authors, see Table 2 ). Epiphytic and adnate taxa of large size were enhanced, particularly during periods of favorable growth conditions (spring). Nutrients also caused a change in the algal chl a, which increased from 0.5–5.8 to 2.1–10.7 μg chl · cm?2. Our results indicate that in oligotrophic forested streams, long‐term nutrient addition has significant effects on the algal biomass and community composition, which are detectable despite the low light availability caused by the tree canopy. Low light availability moderates but does not detain the long‐term tendency toward a nutrient‐tolerant community. Furthermore, the effects of nutrient addition on the algal community occur in spite of seasonal variations in light, water flow, and water chemical characteristics, which may confound the observations. Table 2. Percent abundances of the most frequent taxa in three reaches of the Fuirosos stream. U1 and U2 untreated; E, enriched both in the periods before (bef) and after (aft) the enrichment of the E reach. Acronyms identifying the taxa are indicated.
U1‐bef | U1‐aft | U2‐bef | U2‐aft | E‐bef | E‐aft | ||
---|---|---|---|---|---|---|---|
Achnanthes biasolettiana Grunow | ABIA | 1.1 | 1.2 | 0.4 | 0.1 | 5.4 | 0.7 |
Achnanthes lanceolata (Bréb.) Grunow | ALAN | 7.2 | 1.3 | 5.7 | 7.1 | 7.3 | 2.2 |
Achnanthes minutissima Kütz. | AMIN | 56.2 | 55.0 | 81.2 | 71.4 | 52.2 | 34.5 |
Achnanthes lanceolata v. frequentissima Lange‐Bert. | ALFR | 0.0 | 0.1 | 0.1 | 0.9 | 1.0 | 0.0 |
Amphora inariensis Krammer | AINA | 1.9 | 2.0 | 0.3 | 0.1 | 1.0 | 1.4 |
Amphora ovalis (Kütz.) Kütz. | AOVA | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 1.3 |
Amphora pediculus (Kütz.) Grunow | APED | 0.9 | 2.2 | 0.1 | 0.6 | 3.3 | 1.3 |
Cocconeis pediculus Ehrenb. | CPED | 0.1 | 0.2 | 0.0 | 0.1 | 0.2 | 1.7 |
Cocconeis placentula Ehrenb. | CPLA | 13.7 | 20.3 | 1.8 | 8.4 | 12.3 | 32.4 |
Cymbella silesiaca Bleisch in Rabenh. | CSLE | 0.0 | 0.2 | 0.0 | 0.1 | 0.0 | 0.1 |
Diploneis oblongella (Nägeli) Cleve‐Euler | DOBL | 0.6 | 0.0 | 0.9 | 0.2 | 0.0 | 0.0 |
Fragilaria capucina var. gracilis (Øestrup) Hustedt | FCGP | 0.3 | 1.0 | 0.1 | 0.0 | 0.1 | 3.5 |
Fragilaria capucina var. capitellata (Grunow) Lange‐Bert. | FCCP | 0.0 | 0.2 | 0.0 | 0.1 | 0.4 | 0.6 |
Fragilaria ulna (Nitzsch) Lange‐Bert. | FULN | 0.2 | 1.1 | 0.1 | 0.1 | 0.0 | 1.4 |
Gomphonema angustatum (Kütz.) Rabenh. | GADI | 1.6 | 0.6 | 1.6 | 1.8 | 1.0 | 0.8 |
Gomphonema angustum C. Agardh | GANT | 0.2 | 0.1 | 0.6 | 1.2 | 1.4 | 0.1 |
Gomphonema minutum (C. Agardh) C. Agardh | GMIN | 0.2 | 0.0 | 0.3 | 0.1 | 0.3 | 0.5 |
Gomphonema pumilum (Grunow) E. Reichardt et Lange‐Bert. | GPUM | 1.7 | 0.0 | 2.0 | 1.4 | 1.1 | 0.0 |
Meridion circulare (Grev.) C. Agardh | MCIR | 0.0 | 0.1 | 1.5 | 1.7 | 0.4 | 0.2 |
Navicula antonii Lange‐Bert. | NANT | 0.8 | 0.1 | 0.1 | 0.2 | 0.8 | 0.2 |
Navicula accomoda Hust. | NARB | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
Navicula capitatoradiata H. Germ. | NCPR | 0.3 | 0.0 | 0.1 | 0.1 | 0.0 | 0.3 |
Navicula cryptocephala Kütz. | NCRY | 0.5 | 0.1 | 0.1 | 0.3 | 0.5 | 0.2 |
Nitzschia linearis (C. Agardh) W. Sm. | NLIN | 0.2 | 0.0 | 0.0 | 0.2 | 0.0 | 0.1 |
Nitzschia palea (Kütz.) W. Sm. | NPAL | 0.0 | 0.0 | 0.3 | 0.2 | 0.5 | 0.2 |
Reimeria sinuata (W. Greg.) Kociolek et Stoermer | RSIN | 3.4 | 2.0 | 0.6 | 1.2 | 4.9 | 2.8 |
Rhoicosphenia abbreviata (C. Agardh) Lange‐Bert. | RABB | 8.1 | 5.0 | 0.2 | 0.4 | 3.6 | 9.9 |
Citing Literature
Volume 44 , Issue 3 June 2008
Pages 564-572 相似文献
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Pluripotent stem cells, including induced pluripotent and embryonic stem cells (ESCs), have less developed mitochondria than somatic cells and, therefore, rely more heavily on glycolysis for energy production.1-3 However, how mitochondrial homeostasis matches the demands of nuclear reprogramming and regulates pluripotency in ESCs is largely unknown. Here, we identified ATG3-dependent autophagy as an executor for both mitochondrial remodeling during somatic cell reprogramming and mitochondrial homeostasis regulation in ESCs. Dysfunctional autophagy by Atg3 deletion inhibited mitochondrial removal during pluripotency induction, resulting in decreased reprogramming efficiency and accumulation of abnormal mitochondria in established iPSCs. In Atg3 null mouse ESCs, accumulation of aberrant mitochondria was accompanied by enhanced ROS generation, defective ATP production and attenuated pluripotency gene expression, leading to abnormal self-renewal and differentiation. These defects were rescued by reacquisition of wild-type but not lipidation-deficient Atg3 expression. Taken together, our findings highlight a critical role of ATG3-dependent autophagy for mitochondrial homeostasis regulation in both pluripotency acquirement and maintenance. 相似文献
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Dennis J. Hazelett David V. Conti Ying Han Ali Amin Al Olama Doug Easton Rosalind A. Eeles 《Cell cycle (Georgetown, Tex.)》2016,15(1):22-24
Genome-wide association studies (GWAS) have revealed numerous genomic 'hits' associated with complex phenotypes. In most cases these hits, along with surrogate genetic variation as measure by numerous single nucleotide polymorphisms (SNPs) that are in linkage disequilibrium, are not in coding genes making assignment of functionality or causality intractable. Here we propose that fine-mapping along with the matching of risk SNPs at chromatin biofeatures lessen this complexity by reducing the number of candidate functional/causal SNPs. For example, we show here that only on average 2 SNPs per prostate cancer risk locus are likely candidates for functionality/causality; we further propose that this manageable number should be taken forward in mechanistic studies. The candidate SNPs can be looked up for each prostate cancer risk region in 2 recent publications in 20151,2 from our groups. 相似文献
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Zdeněk Pouzar 《Folia Geobotanica》1966,1(1):356-375
The following genera are redefined:Albatrellus S. F. Gray,Heterobasidion Bref.,Haploporus Bond. et Sing. ex Sing.,Fomitopsis P. Karst. andRigidoporus Murrill two new subgenera are described:Polyporus subgen.Dendropolyporus Pouz. (type:Polyporus umbellatus) andRigidoporus subgen.Neooxyporus Pouz. (type:Polyporus latemarginatus); the genusOxyporus (Bourd. etGalz.)Donk is classified as a subgenus of the genusRigidoporus,Murrill and the generaBjerkandera P. Karst. andLeptoporus quél. are classified as subgenera of the genusTyromyces P. Karst. The new subfamilyAlbatrelloideae Pouz. (genera:Albatrellus andGrifola) is described and 14 new specific combinations are made. The new genusIrpicodon Pouz. (type:Irpex pendulus) is proposed. 相似文献
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A commercially available tissue culture medium has been proven capable of preserving dog kidney function for at least 24 hr after simple cooling. The advantages of using tissue culture medium as preservation fluid instead of plasma or albumin solutions from the infectious and immunological points of view are obvious. An in vitro study was completed using the tissue
Code (animal No.) | Perfusion time (br) | Perfusion pressure mm/Hg | Flow ml/min | Weight gain | pH | pO2 mm/Hg | Histological appearance |
1 | 24 | 70-60 systolic | 96 | 35 | 7.3 | 150–180 | Grossly normal |
2 | 24 | 45-40 diastolic | 108 | 30 | |||
3 | 24 | 96 | 30 | ||||
4 | 48 | 70-60 systolic | 80 | 35 | 7.3 | 150–180 | Grossly normal |
5 | 48 | 45-40 diastolic | 120 | 40 | 7.4 | ||
6 | 48 | 100 | 40 | ||||
7 | 72 | 70-60 systolic | 115 | 40 | 7.4 | 150–180 | Slight vacuolization of the tubular cells |
8 | 72 | 45-40 diastolic | 96 | 40 | |||
9 | 72 | 80 | 40 | ||||
10 | 24 | 70-60 systolic | 110 | 35 | 7.3 | 150–180 | Used for transplantation |
11 | 24 | 45-40 diastolic | 120 | 35 | |||
12 | 24 | 140 | 40 | ||||
13 | 24 | 100 | 30 | ||||
14 | 24 | 96 | 30 |