Distribution and plant community associations of the understory bamboo <Emphasis Type="Italic">Fargesia qinlingensis</Emphasis> in the Foping National Nature Reserve,China

• Introduction  

Fargesia qinlingensis is the primary food source for the endangered giant panda during the summer months in the Qinling Mountains, but little is known about its spatial distribution and plant community associations.     

Trawl fishing impacts on the status of seabed fauna in diverse regions of the globe

Bottom trawl fishing is a controversial activity. It yields about a quarter of the world's wild seafood, but also has impacts on the marine environment. Recent advances have quantified and improved understanding of large‐scale impacts of trawling on the seabed. However, such information needs to be coupled with distributions of benthic invertebrates (benthos) to assess whether these populations are being sustained under current trawling regimes. This study collated data from 13 diverse regions of the globe spanning four continents. Within each region, we combined trawl intensity distributions and predicted abundance distributions of benthos groups with impact and recovery parameters for taxonomic classes in a risk assessment model to estimate benthos status. The exposure of 220 predicted benthos‐group distributions to trawling intensity (as swept area ratio) ranged between 0% and 210% (mean = 37%) of abundance. However, benthos status, an indicator of the depleted abundance under chronic trawling pressure as a proportion of untrawled state, ranged between 0.86 and 1 (mean = 0.99), with 78% of benthos groups > 0.95. Mean benthos status was lowest in regions of Europe and Africa, and for taxonomic classes Bivalvia and Gastropoda. Our results demonstrate that while spatial overlap studies can help infer general patterns of potential risk, actual risks cannot be evaluated without using an assessment model that incorporates trawl impact and recovery metrics. These quantitative outputs are essential for sustainability assessments, and together with reference points and thresholds, can help managers ensure use of the marine environment is sustainable under the ecosystem approach to management.     

Phosphorylation of retinoblastoma protein by viral protein with cyclin-dependent kinase function

As obligate intracellular parasites, viruses expertly modify cellular processes to facilitate their replication and spread, often by encoding genes that mimic the functions of cellular proteins while lacking regulatory features that modify their activity. We show that the human cytomegalovirus UL97 protein has activities similar to cellular cyclin-cyclin-dependent kinase (CDK) complexes. UL97 phosphorylated and inactivated the retinoblastoma tumor suppressor, stimulated cell cycle progression in mammalian cells, and rescued proliferation of Saccharomyces cerevisiae lacking CDK activity. UL97 is not inhibited by the CDK inhibitor p21 and lacks amino acid residues conserved in the CDKs that permit the attenuation of kinase activity. Thus, UL97 represents a functional ortholog of cellular CDKs that is immune from normal CDK control mechanisms.     

EFFECTS OF ACEPROMAZINE ON THREE-PHASE 99mTc-MDP BONE IMAGING IN 11 HORSES

Horses undergoing skeletal scintigraphy can have decreased radiopharmaceutical bone uptake in the limbs. This reduces the diagnostic value of the scan. The aim of the present study was to measure the changes in count density caused by vasodilatation and increased blood flow associated with intravenous injection of acepromazine during bone scintigraphy in normal horses. A three-phase bone scan was performed twice in 11 adult horses to study the effects of acepromazine on the count density of the resultant scintigrams. With acepromazine, there was a statistically significant mean difference of 12 s for initial blood flow and 21 s for peak flow. The time to initial blood flow and time to peak flow occurred earlier for the scans in which acepromazine was used. There were no significant differences in the bone to soft tissue ratios during the soft tissue and bone phases of the scan between procedures. Intravenous administration of acepromazine increases peripheral blood flow causing an earlier onset of the vascular phase during the three-phase bone scan. Acepromazine did not increase the count density of the bone phase scintigrams. As expected, the vasodilatation and increased blood flow associated with intravenous injection of acepromazine affected the count density of the vascular phase of the bone scan.     

Use of computerized image analysis to quantify staphylococcal adhesion to canine corneocytes: does breed and body site have any relevance to the pathogenesis of pyoderma?

An optimized system of computerized image analysis was used to investigate variations in the adherence of Staphylococcus intermedius to canine corneocytes from four different breed groups and six different anatomical sites. S. intermedius showed significantly greater adherence to the head and neck compared with the dorsum, but adherence to the limb, axilla and groin did not differ from other sites. Furthermore, there was significantly greater adherence of S. intermedius to corneocytes from the dorsum, forelimb, axilla and groin of Boxers and Bull Terriers than Spaniels and Hounds. S. intermedius, and also Pseudomonas aeruginosa, exhibited abundant adherence, which was significantly greater than Staphylococcus aureus, Streptococcus canis, Klebsiella pneumoniae and Escherichia coli. In addition, S. intermedius adherence demonstrated a sigmoid dose-response curve with increasing bacterial concentration. These results suggest that S. intermedius adheres to canine corneocytes by a specific receptor-ligand interaction and adheres to the skin of some breeds more avidly than others. However, variations in adherence between body regions would not account for the predilection sites of canine bacterial pyoderma.     

Confirmation of the Prophylactic Value of Paromomycin in a Natural Outbreak of Caprine Cryptosporidiosis

Veterinary Research Communications -     

Hydrothermal Assessment of Temporal Variability in Seedbed Microclimate

The microclimatic requirements for successful seedling establishment are much more restrictive than those required for adult plant survival. The purpose of the current study was to use hydrothermal germination models and a soil energy and water flux model to evaluate intra- and interannual variability in seedbed microclimate relative to potential germination response of six perennial grasses and cheatgrass. We used a 44-yr weather record to parameterize a seedbed microclimate model for estimation of hourly temperature and moisture at seeding depth for a sandy loam soil type at the Orchard Field Test Site in southwestern Ada County, Idaho. Hydrothermal germination response was measured in the laboratory for two seed lots of cheatgrass (Bromus tectorum L.), four seed lots of bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] Löve), three seed lots of bottlebrush squirreltail (Elymus elymoides [Raf] Swezey), and one seed lot each of Sandberg bluegrass (Poa secunda J. Presl.), big squirreltail (Elymus multisetus [J.G. Smith] M.E. Jones), thickspike wheatgrass (Elymus lanceolatus [Scribn. And J.G. Smith] Gould) and Idaho fescue (Festuca idahoensis Elmer). Germination response models were developed to estimate potential germination rate for 13 subpopulations of each seed lot for every hour of the 44-yr simulation. Seedbed microclimate was assessed seasonally and for each day, month, and year, and germination rate-sum estimates integrated for a numerical index of relative site favorability for germination for each time period. The rate-sum favorability index showed a consistent pattern among seed lots for different years, and provides a relatively sensitive indicator of annual and seasonal variability in seedbed microclimate. This index could be used with field data to define minimum weather thresholds for successful establishment of alternative plant materials, in conjunction with weather forecast models for making restoration and fire-rehabilitation management decisions in the fall season, for evaluation of potential climate-change impacts on plant community trajectories, and in optimization schemes for selecting among alternative restoration/rehabilitation management scenarios.     

基于稳健统计学确定高潜在污染土壤Cu、Pb基线值

土壤重金属基线值的确定对于评价重金属积累现状具有重要意义。在存在人为污染的情况下,土壤重金属数据经常强烈地偏离正态分布和对数正态分布,影响统计分析结果的可信度,而稳健统计方法可以降低离群值对统计分析结果的影响。本研究以张家港为研究区域,采用稳健回归方法,建立表层和底层土壤Cu、Pb的回归关系,通过底层土壤Cu、Pb含量计算表层土壤Cu、Pb基线值,并对土壤Cu、Pb积累状况进行评价。结果表明,稳健回归方法确定的表层土壤Cu、Pb基线值可以反映出不同样点间,土壤Cu、Pb背景含量的自然变异。与稳健统计学方法相比,使用国家土壤环境质量标准值,或大区域(江苏省)的土壤背景值,评价自然背景本身存在变异区域的土壤重金属积累状况时,可能会产生较大的误差。     

Carbon storage and spatial distribution patterns of paddy soils in China

Carbon storage in agricultural soils plays a key role in terrestrial ecosystem carbon cycles. Paddy soil is one of the major cultivated soil types in China and is of critical significance in studies on soil carbon sequestration. This paper estimated the organic and inorganic carbon density and storage in paddy soils, and analyzed the paddy soil stock spatial distribution patterns in China based on subgroups and regions using the newly compiled 1:1 000 000 digital soil map of China as well as data from 1 490 paddy soil profiles. Results showed that paddy soils in China cover an area of about 45.69 Mhm², accounting for 4.92% of total soil area in China. Soil organic and inorganic carbon densities of paddy soils in China showed a great heterogeneity. Paddy soil organic carbon densities (SOCD) in soil profile ranged from 0.53 to 446.2 kg/m² (0 to 100 cm) while the paddy soil inorganic carbon densities (SICD) ranged from 0.05 to 90.03 kg/m². Soil organic carbon densities of paddy soils in surface layer ranged from 0.17 to 55.38 kg/m² (0 to 20 cm), with SICD of paddy soils ranging from 0.01 to 21.85 kg/m². Profile based and surface layer based paddy soil carbon storages (SCS) are 5.39 Pg and 1.79 Pg, respectively. Paddy soil organic carbon storage (SOCS) accounts for 95% of the total carbon storage. Profile based and surface layer based SOCS of paddy soils are 5.09 Pg and 1.72 Pg, respectively. Soil inorganic carbon storage (SICS) of paddy soils accounts for 5% of the total carbon storage in China. Profile based and surface layer based paddy SICS are 0.30 Pg and 0.07 Pg respectively. Among all the eight paddy soil subgroups, hydromorphic, submergenic and percogenic paddy soils account for 85.2% of the total paddy soil areas all over China. Consequently, profile based carbon storages of these three subgroups account for 78.1% of the total profile based paddy SCS in China. Most paddy soils in China are distributed in the East-China, South-China and South-west China regions, therefore, 92.6% of China’s profile based paddy SCS focuses on these three regions. The estimates of soil carbon stocks in paddy soils will help to identify areas or soil subgroups which are of particular interest for soil carbon gains and losses. Translated from Ecology and Environment, 2006, 15(4): 659–664 [译自: 生态环境]     

The impact of harvester ants on decomposition, N mineralization, litter quality, and the availability of N to plants in the Mojave Desert

In arid areas of North America, nests of the seed-harvesting ant Pogonomyrmex rugosus tend to be elevated in mineral nitrogen and other soil nutrients relative to other microhabitats. We investigated the roles of decomposition, N mineralization, and plant nutrient uptake in maintaining high standing stocks of nutrients in P. rugosus ant nests. Decomposition rates of standard cellulose substrates placed on the surface of ant nests and other desert microhabitats suggest that conditions found in ant nests and bare areas are conducive to higher rates of decomposition than conditions under shrubs. In laboratory incubations of moist soil, net N mineralization rates were significantly higher in soil from ant nests than from bare areas and under two of three plant species. Net N mineralization rates measured in situ were much lower than those measured in laboratory incubations, but ant nest soil still exhibited higher rates at one of two sites. Litter collected from ant mounds, composed chiefly of seed chaff, was similar in N content to litter collected from underneath the dominant plant species, but had a significantly higher mean δ¹⁵N. Using this distinctive isotope signature as a tracer, we found no evidence that large perennial shrubs tap ant nests as a source of N. An invasive, annual grass species was significantly enriched in ¹⁵N, had higher leaf %N, and produced more seeds when growing on the mound than when growing several meters away; however P. rugosus nest surfaces are typically free of such annuals. We conclude that both high rates of nutrient cycling relative to other Mojave Desert microhabitats and low N utilization by the surrounding vegetation contribute to high standing stocks of mineral N in P. rugosus nests.