Bacterial effect of hydrogen peroxide on urinary tract pathogens.

Bacterial contamination of urinary drainage bags is a frequent source of bladder bacteriuria in patients with indwelling catheters. Previous work demonstrated that the addition of 30 ml of 3% H2O2 prevented bacterial contamination of urinary drainage bags for up to 8 h in patients with urinary infections (greater than 10(5) colony-forming units per ml). Survival curves of a variety of organisms in filter-sterilized urine with various concentrations of H2O2 (0.6 to 0.01%) were constructed. Organisms with high cellular catalase activity (Staphylococcus aureus, Serratia marcescens, and Proteus mirabilis) required 30 to 60 min of exposure to 0.6% H2O2 for a reduction of 10(8) to less than 1 colony-forming unit per ml, whereas Escherichia coli, Streptococcus sp., and Pseudomonas sp. required only 15 min of exposure. The efficacy of H2O2 in urine was maintained despite exposure to room temperature for 5 days and reinoculation with bacterial suspensions. H2O2 is inexpensive and relatively nontoxic, and these data suggest that periodic instillation of H2O2 into urinary drainage bags may eliminate a source of bladder bacteriuria and environmental contamination.     

The influence of aphids on the behaviour of adults of the ladybird beetle,Harmonia axyridis (Col.: Coccinellidae)

The mechanism of prey finding by adultHarmonia axyridis (Pallas) (Coleoptera, Coccinellidae) was investigated in the laboratory by offering beetles small gauze or polyethylene bags containing either aphid-infested leaves or uninfested leaves along with empty control bags. The beetles were attracted to bags containing aphid-infested leaves. It is suggested that adults ofH. axyridis use olfactory and visual cues to detect prey. Mate-searching by males and the mating receptivity of females were enhanced in the presence of an abundance of aphids. The presence of aphids, perceived by the sensory organs of the beetles, possibly influence behaviour other than prey-searching.     

Control of Black Vine Weevil larvae Otiorhynchus sulcatus (Fabricius) (Coleoptera:Curculionidae) in grow bags outdoors with nematodes

Abstract 1 Outdoor trials were carried out during 2001–02 on strawberries grown in commercial growing bags naturally infested with black vine weevil larvae (BVW) Otiorhynchus sulcatus in Co. Wexford, Ireland. 2 The two nematode isolates used in these trials were Heterorhabditis megidis (UK211) and Heterorhabditis downesi (K122), both laboratory cultured. Growing bags received nematodes either once (May 2001), twice (May and October 2001) or three times (May, October 2001 and May 2002). Ten days after each application date, nine blocks (of the total 27) were randomly selected, destructively assessed and discarded. 3 The single application (May 2001) resulted in a mortality of black vine weevil larvae, of 93.4% with H. megidis and 51.3% with H. downesi, compared with the control treatment at that date. Respective figures after the double application (May 2001 and October 2001) were 78.9 and 77.6% and after the triple application (May 2001, October 2001 and May 2002) the figures were 93.7 and 88.1%. 4 Results from these trials clearly indicate that entomopathogenic nematodes are good alternatives to chemical control of the black vine weevil on strawberries grown in growing bags in Ireland.     

猫儿山小鲵(Hynobius maoershanensis)繁殖期生境选择

在广西猫儿山自然保护区的山顶湖、三江源、野人湖等地区,基于植被类型、水体类型、岸边条件、卵袋悬挂物、水中覆盖物、人为干扰程度等20种生境因子,通过61个样方（26个选择样方和35个对照样方）,对猫儿山小鲵繁殖期的生境选择做进行了研究,并得出以下4个主要结论：（1）在基于描述型生态因子的研究中,结果显示选择样方与对照样方在水体类型、岸边条件、水中覆盖物3种因子上差异显著,而植被类型、卵袋悬挂物、人为干扰程度3种生态因子对其生境选择无显著影响。（2）基于14种数值型生态因子的研究结果显示,选择样方和对照样方间的植被盖度、水体面积、水体流速和水底泥沙比方面具有显著差异。植被盖度较低、水体面积较大的水域、水体流速低和水底泥沙比较低的水域是猫儿山小鲵的优选繁殖地。（3）基于14种数值型生态因子的逐步判别表明,通过植被盖度和水底泥沙比2个生态因子可分辨选择样方和对照样方,正确判别率达80.3%,且对于检验也具有最大的贡献值,分别为0.840和0.622。（4）对猫儿山小鲵卵袋对数和14种数值型生态因子的逐步回归分析结果显示猫儿山小鲵在繁殖期生境选择与地表湿度显著正相关,与植被盖度呈显著负相关,高地表湿度和低植被盖度对猫儿山小鲵的产卵量起促进作用。猫儿山小鲵繁殖期间偏好的微生境为较低植被盖度、较大面积水体和较低流速、低水底泥沙、多水中覆盖物、复杂岸边条件的静水型水塘,与选择偏好的微生境相关的生态因子是猫儿山小鲵繁殖期生境选择的主要因子。     

Diethylhexyl phthalate in plastic bags and glass bottles for blood preservation]

The amount of di-(-2 ethyl hexyl) phtalate (D.E.H.P.) is measured in the liquid contained in plastic bags or glass bottles for blood storage. Comparisons between the results show that D.E.H,P. has an equal level in plastic and glass container liquid except for one blood packs series. Particular attention has been paid to obtain solvents and glassware free from D.E.H.P., and to the specificity and the sensitivity of the detection method: a mass fragmentographic technic has been used.     

First-time urea breath tests performed at home by 36,629 patients: a study of Helicobacter pylori prevalence in primary care

Background: The aim of the current study was (1) to describe the use of a ¹³C‐urea breath test (UBT) that was performed by patients at their homes as a part of a test‐and‐treat strategy in primary care and (2) to investigate the prevalence of Helicobacter pylori in patients taking a first‐time UBT. Material and Methods: The patients performed UBTs at home based on the discretion of the general practitioner and mailed the breath bags to a central laboratory for analysis. Each patient was identified by a unique civil registration number. The study was population‐based, and the background population was approximately 700,000 people. Results: From 2003 to 2009, 44,487 UBTs were performed. Of these, 36,629 were first‐time UBTs. In total, 726 of 45,213 breath bags received (1.6%) were unable to be analyzed because of errors with the bags. For both women and men who were ≤45 years of age, positive H. pylori declined over the time course of the study (women: 19.6% in 2003 to 17.6% in 2009, p < .01; men: 20.7% in 2003 to 16.9% in 2009, p < .001). Patients who were older than 45 years had significantly higher positive H. pylori results than younger patients. Conclusions: A test‐and‐treat system was possible to implement that allowed patients to perform UBTs at their homes. The results of the first‐time UBTs demonstrated that approximately one of five patients who presented with dyspepsia in the clinical setting of Danish primary care was infected with H. pylori.     

Rehabilitating Seagrass by Facilitating Recruitment: Improving Chances for Success

Attempts to arrest seagrass loss through numerous rehabilitation methods have traditionally produced inconsistent results. On Australia's southern coast, hessian bags made from biodegradable jute fibers show promise for rehabilitating Amphibolis antarctica by facilitating recruitment of seedlings in situ. Testing ways to improve the performance of bags (i.e. increasing seagrass recruitment and establishment) showed that bags with a coarse outer weave of hessian facilitated greater seedling densities (approximately 1700 individuals/m²) than bags with a fine outer weave, but the content of bags (sand vs. sand and rubble mixture) had little effect. Isolated bags facilitated greater longer term densities than bags grouped together, while similar densities were sampled up to 80 m away from a natural meadow. Lastly, bags that had spent less time in situ initially facilitated more recruits than older bags, but longer term (21–32 months) retention was similar among bag ages. Collectively, the results suggest hessian bags can be a relatively simple, cost‐effective, and environmentally friendly method for rehabilitating Amphibolis seagrass, with few considerations in their use other than their physical architecture and arrangement (e.g. isolated coarse‐weave bags).     

Storage of apheresis platelets in ethylene-vinyl acetate copolymer bags: relationship between the bag size and the number of platelets maintaining aerobic metabolism

The present study was designed to determine whether a bag made from ethylene-vinyl acetate copolymer (EV) with superior flexibility at subzero temperature is suitable for a storage container of single-donor apheresis platelets. Apheresis platelets were stored with 100 ml plasma in 1-liter bags made of EV or standard polyvinyl chloride (PVC) plastic at 22 degrees C with constant agitation. The oxygen permeability of the 1-liter EV bag averaged 1447 nmol/min/atm, which was about 1.5 times higher than that of PVC bags. The partial oxygen tension (PO2) of platelet concentrates (PC) has linearly decreased to 16 mm Hg with increasing platelet counts. The level of the partial carbon dioxide was always higher in EV bags than in PVC bags. Oxygen consumption rates of platelets stored in EV and PVC bags with a sufficient oxygen supply averaged 1.25 and 1.20 nmol/min/10(9) platelets, respectively. The rates of glucose consumption and lactate production were not changed in two bags. Ninety percent of the total ATP production of about 8 nmol/min/10(9) platelets were generated through the aerobic metabolism. The platelet counts in the 1-liter EV and PVC bags, at which PO2 is 16 mm Hg, were 2.2 and 1.5 x 10(11) platelets, respectively. The study indicates that apheresis platelets stored in EV bags at 22 degrees C have no different metabolic changes when compared with those of PVC bags. In addition, the number of platelets maintaining the aerobic metabolism is 1.5 times higher than that of PVC bags.     

不同颜色果袋对‘巨峰’葡萄果实中挥发性成分的影响

以‘巨峰’葡萄为试材,研究白袋、绿袋、红袋、蓝袋4种不同颜色果袋对葡萄成熟期果实中挥发性成分的影响,为葡萄专用果袋的研发提供理论依据.结果表明:不同颜色果袋可为葡萄果实的发育提供特定的光环境,不同套袋处理葡萄成熟期果实中的挥发性成分差异显著.‘巨峰’葡萄成熟期果实中检测到酯、醛、醇、酮类、萜烯类和芳香族化合物,对照、白袋、绿袋、红袋和蓝袋处理成熟期果实检测到的挥发性组分分别为33、37、38、32和34种.与对照相比,白袋处理乙酸乙酯、己酸乙酯等酯类物质含量降低,己醛、反式-2-己烯醛、癸醛含量增加;绿袋处理除3-己烯酸乙酯、反式-2-己烯酸乙酯、3-羟基丁酸乙酯、反式-2-己烯醛、(反,反)-2,4-己二烯醛、癸醛、苯乙醇外,其他共有组分的含量均出现降低;红袋处理乙酸乙酯、己酸乙酯等酯类物质含量降低,己醛、反式-2-己烯醛等的含量出现降低;蓝袋处理乙酸乙酯、己酸乙酯等主要酯类物质的含量未发生较大变化,己醛、反式-2-己烯醛等的含量出现升高.在非共有组分中,套袋处理中醇类组分的种类减少,萜烯类、芳香族化合物的种类增加.总体上,蓝袋处理果实中主要的‘果香型’酯类组分含量最高,白袋处理果实中主要的酯类组分及‘青草香型’的醛类组分含量较高,绿袋、红袋处理果实主要香气组分含量较低.     

Leaching of plasticizers from and surface characterization of PVC blood platelet bags.

The leaching of phthalate plasticizers from four types of blood platelet bags was investigated. The anticoagulant solutions used in the blood collection bags had pH values of 5.64 +/- .04 and contained no detectable amounts of phthalates. Platelet bag materials from each bag were soaked in normal salines for up to 5 days. The salines were tested for the leached phthalates from the bags but none could be found. However, di-(2-ethylhexyl) phthalate (DEHP) leached out of the PL-146 and Terumo bags into bovine calf serum used for soaking the bag materials. There was an increase in the amount of DEHP leached from about 1.1 mg at the end of one day to about 3.3 mg per gm of bag material at the end of a five day extraction with the serum. In PL-732 sets, a platelet bag made of a specialty polyolefin, the amount of DEHP leached out was less than 0.02 mg per g of bag material. CLX bags, which contained tri-(2-ethylhexyl) trimelliate (TETM) as a plasticizer, showed a negligible amount of it leaching into the calf serum. Infra-red spectra showed that PL-146 bags had been coated with a layer of a fatty acid amide while the Terumo bags contained a layer of a silicone fluid on their inner surfaces. CLX bags showed a coating of stearates, which were probably soaps of calcium or zinc. Scanning electron microscopy (SEM) showed that the inner surfaces of each brand of the bag were distinctly different morphologically. The two PVC bags were very similar whereas the surfaces morphology of PL-732 was rougher. Terumo bag had a different surface morphology than those of the other bags whereas the CLX bags had a very regular surface pattern. The exact significance of the surface morphology is not certain but excessively rough surfaces may not be desirable for the bags.     

Role of transported particulate organic matter in the macroinvertebrate colonization of litter bags in streams

1. The exposure of mesh litter bags has been widely used to investigate the role of benthic macroinvertebrates in leaf processing in freshwaters. In this sense, several studies have related litter bag breakdown rates to the presence of colonizing invertebrates. A possible confounding factor in such experiments is that the litter bags trap suspended particulate organic matter that can itself attract invertebrate colonists, irrespective of the intended experimental treatment.
2. We attempted to quantify the accumulation of particulate organic matter (POM) within litter bags and to investigate its possible impact on macroinvertebrate density and richness. In seven headwater forested streams we exposed mesh bags filled either with beech leaves ( Fagus sylvatica ) or with plastic strips of an equal surface area.
3. Principal component analysis (PCA) showed that bag type and stream were the main explanatory variables for invertebrate colonization and POM accumulation within the bags. In contrast, there was little variation among sampling dates (6.4% of the total inertia).
4. The accumulated POM within the bags was substantial (up to 8.83 g ash-free dry mass (AFDM)) but highly variable among sites (mean from 0.32 to 4.58 g AFDM). At each of the seven sites, both richness and abundance of invertebrates were positively correlated with the mass of accumulated POM in bags. Macroinvertebrate colonization (notably taxon richness) was directly linked with the quantity of POM accumulated.
5. Our findings provide evidence of a potential pitfall in linking invertebrates to litter processing in mesh bags, particularly when large amounts of POM, entrained in stream flow, accumulate within the bags. An evaluation of the POM mass trapped in litter bags could account for the erratic patterns sometimes observed in their colonization by invertebrates.     

Fungal deterioration of melon seeds stored in jute sacks and polyethylene bags in Ago-Iwoye,southwestern Nigeria

Laboratory studies were carried out in the Department of Biological Sciences, Ogun State University, Ago-Iwoye, southwestern Nigeria, to determine the extent of fungal deterioration of melon seeds stored in two types of storage bags viz; jute and polyethylene bags. Melon seeds of varieties Tc139 and V2 were stored in jute and polyethylene bags under ambient conditions using the 2 × 2 factorial design (variety vs type of bag) for 12 months. The moisture content (mc), incidence of visible mouldiness (ivm) and germinability of the stored seeds were determined monthly. The mc of Tc139 ranged from 6.1 to 6.7% in jute and 6.2 to 6.5% in polyethylene bags. The ivm which was initially 2.1% increased to 10.7% and 5.5% in jute and polyethylene bags respectively, after 12 months in storage. The germination percentage decreased from 96.3% to 28.7% and 45.3% in jute and polyethylene bags, respectively. The mc of V2 stored in jute and polyethylene bags varied from 5.9 to 6.4%, and 5.8 to 6.2%, respectively. The ivm increased from 1.8% before storage to 8.9% and 4.8% in jute and polyethylene bags, respectively, after 12 months. The percentage seed germination declined from 98.0%to 37.3% in jute and 48.7% in polyethylene bags after 12 months. Decreased incidence of field fungi namely: Alternaria, Botryodiplodia theobromae, Cladosporium, Fusarium and Macrophomina phaseolina was accompanied by simultaneous increase in storage fungi viz: Aspergillus, Penicillium, and Rhizopus with prolonged storage. This revised version was published online in June 2006 with corrections to the Cover Date.     

In situ studies on the breakdown ofNymphoides peltata (Gmel.) O. Kuntze (Menyanthaceae); Some methodological aspects of the litter bag technique

Summary Thein situ breakdown ofNymphoides peltata (Gmel.) O. Kuntze has been studied with special attention for methodology by: (1) using fresh and pre-dried material to establish the influence of pre-drying on breakdown and losses of nutrient stocks during decomposition; (2) enclosing different amounts of material in litter bags; (3) using litter bags with different mesh sizes, and (4) placing litter bags in water (floating leaves, petioles), on the sediment (long shoots) and in the hydrosoil (short shoots, roots). Of the material incubated in water, the floating leaves decomposed at a faster rate than the petioles, while the long shoots had the slowest breakdown. In the sediment the short shoots disappeared at a faster rate than the roots. By incubating the same morphological structure, both in the water and the sediment it appeared that the rate of breakdown was faster in the upper layers of the sediment. Pre-dried plant parts showed in water a larger initial weight loss than normal senescent plant parts, while in the sediment dried plant parts had a significantly slower loss of mass than the freshly incubated structures. Losses of nutrient stocks during decomposition were also markedly altered by pre-drying the material. When a larger amount ofNymphoides material was enclosed in the bags a tendency of a faster decay could be demonstrated. Macro-invertebrates colonized the litter bags with the 0.5 mm mesh size but usually could not-enter the 0.25 mm mesh size bags. The browsing of the detritivores did not result in a faster disappearance of organic matter, but organic matter must have been transported into the bags resulting in a larger amount of remaining organic matter when compared with the 0.25 mm mesh size bags.     

西双版纳热带季节雨林凋落叶分解与土壤动物群落：两种网孔分解袋的分解实验比较

 以西双版纳热带湿性季节沟谷雨林混合凋落叶作为分解基质,在不同位置季节雨林样地,采用不同网孔（ 2和0.15 mm）分解袋,开展大中型土壤动物对雨林凋落叶分解影响的实验,测定了不同网孔分解袋土壤动 物多样性、凋落叶分解速率和主要养分元素释放状况。结果显示：2 mm网孔分解袋土壤动物类群相对密度 年均值为2.67～2.83目•g－1凋落物干重,个体相对密度年均值为22.3～21.77个•g－1凋落物干重,显著 高于0.15 mm网孔分解袋的类群相对密度0.27～0.28目•g－1凋落物干重和个体相对密度2.88～2.77个•g－ 1凋落物干重（p<0.01）,并且0.15 mm网孔分解袋中极少量的动物个体主要为小型类群弹尾目和蜱螨目（ 原生动物、湿生土壤动物线虫不计）,由此我们视2 mm网孔分解袋凋落叶分解由绝大多数土壤动物和其它 土壤生物共同作用,而0.15 mm网孔分解袋基本排除了大中型土壤动物对袋内凋落叶分解的影响。2 mm网 孔分解袋凋落叶物质失重率（71%左右）、分解率指数（1.88～2.44）和主要养分元素释放率明显高于 0.15 mm分解袋（34%～35%,0.48～0.58）。通过比较两种不同网孔分解袋凋落叶失重率和元素释放率的 差异,显示出季节雨林大中型土壤动物群落对凋落叶物质损失的贡献率为年均值46%左右,并使凋落叶C/N 和C/P明显降低,而对不同元素释放率的影响不同,其中对N、S和Ca元素释放率的影响较大,而对K素释放 的影响作用最小。相关分析显示,2 mm网孔分解袋内土壤动物群落类群和个体的相对密度与凋落叶物质残 留率有较好的负相关关系,而群落香农多样性指数与凋落叶分解率指数表现出一定的正相关关系。     

A technical bias: differences in cooling rates prevent ampoules from being a reliable index of stem cell cryopreservation in large volumes

Ampoule tests are commonly used as an index of the cryopreservation efficiency of marrow stem cells in bags. We have studied the recovery of hematopoietic progenitor cells (CFU-GM, BFUe) in 52 ampoules and compared it to the recovery in 83 standard bags. Our data showed significantly deficient CFU-GM and BFUe recoveries (respectively 47 +/- 31% and 31 +/- 30%) in ampoules when compared to bags (respectively 72 +/- 22% and 64 +/- 19%; P less than 0.001). Moreover, a good progenitor cell recovery (greater than or equal to 50%) was observed in only 46% of frozen ampoules versus 100% observed in frozen bags (P less than 0.05). We were able to relate this nonoptimal recovery to an excessively rapid freezing rate of -9 degrees C/min following the release of fusion heat which occurred in ampoules, while the freezing rate was constantly maintained at -2 degrees C/min in the corresponding bags. We therefore conclude that the cooling conditions have to be carefully controlled to ensure that the bags and ampoules are both cooled under the same conditions. Otherwise, ampoules would not be a reliable index of the true progenitor cells' cryopreservation efficiency in bags.     

Validation of in sacco method: influence of sampling site,nylon bag or rumen contents,on fibrolytic activity of solid-associated microorganisms

Three ruminally cannulated cows, fed twice daily with a 70:30 forage:concentrate diet, were used to investigate the differences in fibrolytic activity of solid-associated microorganisms between nylon bags and rumen contents. Two different grass hays (regrowth and late harvested) were incubated in ruminal nylon bags. After 2 h or 23 h incubation time, pH was measured in bags and rumen contents, and enzymes of solid-associated microorganisms were extracted from bag residues and surrounding digesta by grinding, freezing, defrosting and sonication. Xylanase, avicelase, β-D-xylosidase and β-D-glucosidase activities were measured. Activities were lower in bag residues than in rumen digesta, and differences were greater after 2 h than after 23 h incubation time. Causes of these differences are discussed. For each incubation time and each enzyme, the differences in solid-associated microorganisms activities between rumen and bags contents were independent of the quality of hay in the bag. Thus the lower fibrolytic activity inside the bags may account for an underestimation of in vivo ruminal fiber degradation by the in sacco method, but this underestimation may be similar whatever the nature and content of forage cell walls.     

The influence of invertebrates on the breakdown ofPotamogeton pectinatus L. in a coastal marina (Zandvlei,South Africa)

The influence of invertebrates upon the decomposition ofPotamogeton pectinatus L. in a coastal Marina system was examined over 112 days using litter bags. Invertebrate inclusion bags (2 mm mesh, 5 mm holes) registered a dry mass loss of 1% d^–1, while exclusion litter bags (80 µm mesh) produced a 0.4% mass loss d^–1 (a 2.5 fold difference). Losses of ash and N from inclusion bags were greater than those from exclusion bags (p < 0.05). There was a three fold difference between the two treatments in the time taken for litter to breakdown to half the initial stock: T_1/2 for inclusion bags = 43 d, exclusion bags = 130 d. In both treatments, minerals showed an expected rapid loss, due to leaching, with a subsequent slow increase relative to the dry material remaining. A total of nine invertebrate taxa was recorded from inclusion bags, with a peak biomass of 64 mg g^–1 dry massPotamogeton bag^–1 reached at 64 days after immersion. Grazing amphipods,Melita zeylanica Stebbing andAustrochiltonia subtenuis (Barnard), numerically dominated the litter bag fauna, whileM. zeylanica and nymphs of the zygopteran predatorIschnura senegalensis (Rambur) formed most of the biomass. Scanning Electron Microscopy indicated heavy grazing of micro-organisms by invertebrates, with major qualitative differences occurring 112 days after immersion. Invertebrates significantly accelerated the rate of litter breakdown through their feeding activities, assisting fragmentation and thus contributing to plant losses and also by increasing the surface area for microbial colonisation and attack.     

Metabolic activity of pathogenic bacteria during semicontinuous anaerobic digestion.

In natural environments such as anaerobic digesters, bacteria are frequently subjected to the stress of nutrient fluxes because of the continual changes in the flow of nutrients, and to survive, they must be capable of adapting readily to nutrient changes. In this study, the metabolic activities of Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Listeria monocytogenes, and Campylobacter jejuni were studied within culture bags (Versapor-200 filters, 0.22-microns pore size) in laboratory anaerobic digesters. The metabolic activity of these bacteria was indicated by their adenylate energy charge (EC) ratios and their ability to incorporate [3H]thymidine, which was related to the respective changes in viable numbers within the culture bags during anaerobic digestion. Fluctuations in the adenylate EC ratios, the uptake of [3H]thymidine, and the viable numbers of E. coli, S. typhimurium, Y. enterocolitica, and L. monocytogenes cells were probably due to constant changes in the amount of available nutrients within the anaerobic digesters. The viability of S. typhimurium increased quickly after a fresh supply of nutrients was added to the system as indicated by the uptake of [3H]thymidine and an increase in the adenylate EC ratios. The viable numbers of E. coli, S. typhimurium, Y. enterocolitica, and L. monocytogenes organisms declined rapidly from 10(7) to 10(8) CFU/ml to 10(3) to 10(4) CFU/ml and remained at this level for an indefinite period. The decimal reduction time calculated during the period of exponential decline ranged from 0.8 to 1.2 days for these bacteria. C. jejuni had the greatest mean decimal reduction time value (3.6 days).(ABSTRACT TRUNCATED AT 250 WORDS)     

一种采集水稻二化螟卵(块)的高效简便新方法

比较了二化螟Chilosuppressalis卵块的塑料袋收集法和稻株法。结果表明 ,塑料袋法和稻株法收集的卵粒总数及卵孵化率都没有显著的差异 ,均为 2 79粒卵 雌蛾和 95 %。塑料袋法收集的卵块数较稻株法的多 ,但小卵块比例较高 ( <1 0 0粒卵 卵块 )。还讨论了采用塑料袋法收集二化螟及其它昆虫卵的优点。     

Ectomycorrhizal hyphae structure components of the soil bacterial community for decreased phosphatase production

Ectomycorrhizal fungi (EMF) provide nutrients to their hosts by means of hyphae that extend beyond nutrient-depleted rhizosphere soil. Soil bacteria may compete with EMF for nutrients or may act synergistically to enhance nutrient supply to hosts. To assess the interactions between hyphae and bacteria, two types of small, sand-filled mesh bags were incubated in a Pseudotsuga menziesii/Betula papyrifera forest. The bags allowed ingrowth by EMF (35-μm mesh) or excluded hyphae (0.5-μm mesh), while allowing migration of soil bacteria. After incubation, bacteria were isolated from bags using a method to enrich for Gram-positive bacteria. Isolates were assayed for phosphatase and N-acetyl glucosaminidase (NAGase) activities to assess the potential to access organic phosphorus and nitrogen. The average phosphatase activities were higher in exclusion than ingrowth bags, while NAGase activities did not differ. Streptomyces isolates, which are expected to be strong competitors and antagonists of EMF, were more prevalent in ingrowth bags and yet had lower phosphatase activities. Furthermore, there were no indications of antagonism between fungi and Streptomyces, as there were no increases in NAGase activities in ingrowth bags. We conclude that fungal hyphae can structure components of the soil bacterial community for decreased extracellular enzyme production.