Fungal biodiversity in the air of Turin

The qualitative fungal composition of Turin 's atmospheric environment was surveyed, carrying out a twelve-month study and collecting with a single stage volumetric sieve sampler on Dermasel agar supplemented with 0.4 g l^–1 cycloheximide and 0.05 g l^–1 chloramphenicol. We isolated 165 species and 2 varieties of mesophilic fungi from 58 genera and 26 thermotolerant species from 12 genera. Penicillium, Aspergillus, Acremonium, Chrysosporium, Scopulariopsis, Malbranchea, Paecilomyces, Phialophora and Cladosporium were in sequence the genera most rich in mesophilic species; Aspergillus, Penicillium, Chrysosporium and Scopulariopsis the most rich in thermotolerant species. Many of the species isolated are rarely or never recorded in the atmospheric environment. Cycloheximide can thus be said to select among airborne fungi, giving a characteristic picture.Abbreviation CH Cycloheximide - cfu colony forming unit     

Adaptation to a Starch Environment and Regulation of alpha-Amylase in Drosophila

The adaptation to glucose and starch foods insix species, D. melanogaster, D.virilis, D. saltans, D. funebris,D. levanonensis and D. americana, wasstudied by measuring productivity. D.melanogaster and D. virilis adapted more to thestarch environment than to the glucose environment,while D. saltans adapted more to the glucoseenvironment than to the starch environment. D.funebris, D. levanonensis, and D. americana did not distinctlyadapt to either environment. In addition, the regulationof amylase in the six species was investigated bymeasuring the levels of amylase activity with glucoseand starch food environments. The levels of amylaseactivity in D. levanonensis and D.saltans were substantially low, indicating thatthese species cannot utilize starch as a carbon source.The starch-adapted species, D. melanogaster and D.virilis, showed higher levels of amylase activitywith the starch environment and higher inducibility.These results suggest that changing the regulation ofamylase is important for the adaptation to a starch environment inDrosophila.     

The role of plant genotype,environment and gender in resistance to a specialist chrysomelid herbivore

Summary Patchiness in herbivore attack is a well-documented phenomenon. When neighboring plants suffer vastly different levels of attack, then one suspects genotypic differences among plants to be the underlying mechanism. In this study, I use common garden experiments in two natural, but divergent, habitats at the Cedar Creek Natural History Area in central Minnesota to determine the role of plant genotype, environment and gender in plant resistance to a specialist herbivore. Resistance was measured by larval survivorship and weight. Eight clones ofRhus glabra were selected and 12 equal-aged ramets were dug up and planted in two gardens (each garden received 6 ramets per clone). First instarBlepharida rhois (Coleoptera: Chrysomelidae) larvae of known parentage were transferred to ramets and censused every other day. At the end of the experiment, larvae were collected and weighed. Analysis of variance was used to determine the importance of plant genotype, environment and gender on larval mortality and weight. The experiment was repeated in its entirety one month later. Both plant genotype and environment significantly affected larval survivorship in the first run of the experiment. No interactions were significant. Results from the second run indicated marginally significant genotype and environment main effects, and a genotype by environment interaction in larval survivorship. There was a significant genotype by environment interaction in larval weight on the same run. In neither run did clone gender have significant affects on resistance.     

Decline in zoobenthos densities in the profundal sediments of Lake Mendota (Wisconsin,USA)

High densities of zoobenthos inhabited Lake Mendota's profundal zone in the early 1900s through the mid-1940s. Chaoborus punctipennis was the most abundant organism during the winter, along with moderate densities of Chironomus spp., Pisidium sp., oligochaetes, and Procladius sp. By the early 1950s, Chaoborus punctipennis densities had declined to 10% of former levels, while Chironomus increased significantly. However, by the mid-1960s, Chaoborus, Chironomus, and Pisidium densities had decreased to very low population levels. By 1987–89, Pisidium was no longer found. Zoobenthos that had not decreased from earlier surveys were oligochaetes and Procladius, although further sampling of oligochaetes is needed to confirm current densities. These organisms are the most tolerant of severe anoxia.Four possible reasons for this decline were evaluated: (a) decline in food availability, (b) increase in fish predation, (c) use of toxic insecticides in the drainage basin, and (d) changes in the profundal sediment environment. Based on literature information and long-term data for Lake Mendota, a change in the profundal sediment environment is the most likely explanation for the decline in the less-tolerant zoobenthos species. Although the duration and extent of anoxia in the hypolimnion have not changed since the early 1900s, hypolimnetic ammonia and hydrogen sulfide concentrations apparently have increased as Mendota became more eutrophic after the mid-1940s. However, further study is needed to determine if these higher concentrations or other factors were responsible for the dramatic decline in lake Mendota's profundal zoobenthos.     

Shade adaptation and shade tolerance in saplings of three Acer species from eastern North America

Summary Saplings of three, co-occurring maple species in a mature maple-beech forest differed in a suite of structural and physiological characters that separated the canopy species, Acer, saccharum, from the two subcanopy species, A. pensylvanicum and A. spicatum. Acer saccharum had both more dense wood and tougher and heavier but thinner leaves than the subcanopy species. Acer pensylvanicum had the largest, lightest leaves with high stomatal density and its canopy architecture was the most effective in terms of leaf display for light interception. Acer spicatum had weaker wood similar to that of A. pensylvanicum but also small, soft and relatively poorly displayed leaves. Both subcanopy species maintained marginally higher average rates of photosynthesis over the growing season in the understory environment. We consider juvenile A. saccharum only shade-tolerant, capable of persisting through long periods in the closed canopy until a gap occurs but not specifically adapted to the understory environment. Juvenile A. sacchrum appears to be constrained functionally by the requirements set by the canopy environment that adults will occupy. Characters such as high wood density are already expressed in the understory sapling; this investment in denser wood slows the growth of saplings, but is necessary for structural reasons in the adult. Juvenile A. saccaharum have morphological and photosynthetic characters better suited to gas exchange and extension growth under the increased photon flux densities in large forest gaps, characteristics that will also be advantageous in the sunlit canopy environment of adults.Both subcanopy maples appear to be more truly shade-adapted, although in somewhat different ways. Acer pensylvanicum has characteristics that enhance the potential for capture and utilization of sunflecks and is able to sustain higher growth rates than A. saccharum in the shaded subcanopy environment. Acer spicatum shares some shade-adapted features with A. pensylvanicum, and its habit of lateral spread through stem layering may confer an additional advantage in foraging for small light gaps.     

Outbreak of nosocomial Acinetobacter baumannii bacteremia in a high risk ward

Acinetobacter baumannii is emerging as a major cause of nosocomial infections particularly in high risk patients. Being resistant to adverse environmental conditions, it can stay for prolonged periods in the hospital environment. We report an outbreak in the medical oncology ward where nine patients suspected of bacteraemia were blood culture positive forA. baumannii from the two samples each, one collected through the i.v. cannula and another through the peripheral venous puncture. The bacteria was also isolated from the environmental sources from the various samples collected. The biotype, antibiogram, cellular protein profiles on SDS-PAGE and the restriction enzyme analysis patterns of the patient isolates and the environmental isolates were similar. This points to the environment as a source of infection. With reinforcement of proper barrier nursing and use of disposable heparine ampoules it was possible to control the outbreak.     

新疆不同栖息地赤麻鸭肠道菌群多样性研究

【目的】探讨天山北麓赤麻鸭肠道细菌多样性及其与栖息地环境之间的关系。【方法】于2017年秋季在天山北麓5个栖息地随机采取新鲜的赤麻鸭粪便,用细菌16S rDNA通用引物扩增V3–V4区并进行高通量测序,使用BLAST、USEARCH和QIIME等软件和在线工具分析各栖息地样品菌群组成与差异。【结果】从赤麻鸭粪便样本中共获得16S rDNA有效序列408 036条,聚类产生1 014个操作分类单元(operational taxonomic unit,OTU)。样品中的细菌分属25个门和397个属。在门分类阶元上,变形菌门和厚壁菌门在所有样品中均为优势菌,相对丰度较高的还包括拟杆菌门、梭杆菌门、放线菌门、蓝藻细菌、螺旋体门、Saccharibacteria和迷踪菌门,但以上细菌在各栖息地样品中的相对丰度存在差异。在属分类阶元上,各栖息地样品的菌群组成差异显著,艾比湖、安集海水库、奎屯水库、蘑菇湖水库和八一水库样品的优势菌分别为鲸杆菌属、巨单胞菌属、假单胞菌属、乳酸菌属和链球菌属。对不同样品菌群组成和差异分析表明,赤麻鸭胃肠道菌群组成受环境和食源的影响较大。【结论】新疆5个栖息地赤麻鸭肠道...     

Acquisition of symbiotic dinoflagellates (Symbiodinium) by juveniles of the coral Acropora longicyathus

Scleractinian corals may acquire Symbiodinium from their parents (vertically) or from the environment (horizontally). In the present study, adult colonies of the coral Acropora longicyathus from One Tree Island (OTI) on the southern Great Barrier Reef (Australia) acquired two distinct varieties of symbiotic dinoflagellates (Symbiodinium) from the environment. Adult colonies had either Symbiodinium from clade C (86.7%) or clade A (5.3%), or a mixture of both clades A and C (8.0% of all colonies). In contrast, all 10-day-old juveniles were associated with Symbiodinium from clade A, while 83-day-old colonies contained clades A, C and D even though they were growing at the same location. Symbiodinium from clade A were dominant in both 10- and 83-day-old juveniles (99 and 97% of all recruits, respectively), while clade D was also found in 31% of 83-day-old juveniles. Experimental manipulation also revealed that parental association (with clade A or C), or the location within the OTI reef, did not influence which clade of symbiont was acquired by juvenile corals. The differences between the genetic identity of populations of Symbiodinium resident in juveniles and adult A. longicyathus suggest that ontogenetic changes in the symbiosis may occur during the development of scleractinian corals. Whether or not these changes are due to host selective processes or differences in the physical environment associated with juvenile versus adult colonies remains to be determined.     

Ecological significance of light controlled seed germination in two contrasting tropical habitats

Summary The effects of temperature, photoperiod, phytochrome photoreversion and the response to a R/FR ratio gradient were investigated in seeds of four species from two contrasting tropical habitats; two species from a rain forest (Cecropia obtusifolia and Piper umbellatum) and two from a high altitude lava field covered by low vegetation (Buddleja cordata and Chenopodium ambrosioides). In the rain forest seed species the photoblastic response seems to be adapted to light quality changes due to canopy destruction, on the other hand, the lava field seed species seem to be adapted to instantaneous light stimulus such as would be produced by the sudden exposure of a buried seed to the soil surface light environment.     

高亚硝酸盐环境下不同生长速率凡纳滨对虾肠道微生物多样性研究北大核心

【目的】高亚硝酸盐环境中饲养的凡纳滨对虾(Litopenaeus vannamei),在养殖结束时其生长速率和体重往往差异较大。本研究旨在探讨在高亚硝酸盐环境下饲养的对虾生长速率与肠道菌群结构和功能的相关性。【方法】本研究通过收集高亚硝酸盐条件下快速生长对虾(rapidly growing,RG)、正常生长对虾(normally growing,NG)和缓慢生长对虾(slowly growing,SG)的肠道和海水样品,通过16S rRNA基因测序、线性判别分析[line discriminant analysis(LDA)effect size,LEfSe]等进行分析。【结果】发现SG的细菌群落多样性与RG和NG不同。主坐标分析(principal coordinate analysis,PCoA)分析表明,NG的群落组成与RG比SG更相似。通过LEfSe差异分析发现,RG中火色杆菌科(Flammeovirgaceae)、黄杆菌科(Flavobacteraceae)和浮酶菌科(Planctomycetaceae)的丰度较高,而SG中脱硫弧菌科(Desulfovibrionaceae)、希瓦氏菌科(Shewanellaceae)和弧菌科(Vibrionaceae)的丰度显著增加。【结论】本研究发现,在高亚硝酸盐环境下,肠道微生物群落的氮代谢能力是造成对虾不同生长速度的原因。该研究将为虾的工业化养殖提供指导。     

Recovery Deficiency Following Tree Mortality in Mangroves of Two Caribbean Islands: Field Survey and Statistical Classification

Mangrove species are well adapted to the harsh ecological conditions of their environment throughout the tropics. However, in the islands of Guadeloupe and Martinique (Lesser Antilles), deficient forest recovery was evidenced in 43 mangrove sites (>1000 m²) affected by apparently natural tree mortality. Such sites were recorded from four chronological sets of aerial photographs between 1950 and 1995, and field-investigated in terms of environment and vegetation characteristics. Given the speculative relationship between the slow-regenerating vegetation and its present environment within non-steady state, disturbed sites, statistical analyses arbitrarily matching physicochemical and biological data were primarily avoided. On one hand, principal component analysis (PCA), combined with an agglomerative hierarchical classification, was performed on environmental, rank-ordered data; on the other hand, multidimensional scaling (MDS) was implemented on vegetation data. Discriminant analyses (DA) further characterized the environment/vegetation interrelationships for each site type. Ultimately, three main types of mortality sites have been distinguished among the study areas. One type clustered the sites showing the lowest salinity values and the highest surge vulnerability whose dominant mangrove species is Rhizophora. Another type presented highly saline sites having clayey soils with pure, stunted, Avicennia stands. The last type consisted of peculiar forest gaps on deep, compact, peat soils. During the rainy season, these sites turned into shallow ponds scattered with living, young Rhizophora and large, standing, dead Avicennia. The authors suggest that this classification may serve as a comprehensive framework to test subsequent hypotheses (hurricanes, droughts…) on the origins of natural massive tree mortality and the causes of recovery deficiency in mangroves of the Caribbean.     

人和动物条件致病菌环境菌株侵染植物的研究进展北大核心CSCD

越来越多的研究表明某些在环境中普遍存在的人与动物的病原微生物能够跨界侵染不同生物界的寄主。本文就Serratia marcescens,Enterobacter cloacae,Pseudomonas aeuriginosa,Klebsiella pneumoniae等动物条件病原细菌环境菌株跨界侵染植物的研究现状进行了综述。这些病原菌在自然界中普遍存在,能够利用与感染人类相同或不同的侵染策略跨界侵染植物,以拓宽其寄主范围。其中,肺炎克雷伯氏菌(Klebsiella pneumoniae)能在自然条件下引起玉米发生顶腐病,揭示了环境中的某些植物可作为各种病原细菌的天然储存库,在条件合适的情况下可能会感染人类和动物,以及在食品生产中的潜在危害。对这些跨界病原菌的研究,在人、动物和植物流行病学上具有非常重要意义,也为环境科学提出了新的研究热点。     

Distribution and tissue retention of cesium-134 and cobalt-6o in the nile catfish clarias lazera (cuv. & val.)

The Nile catfish, Clarias lazera was found to concentrate radioactive cesium-134 and cobalt-6o from the aquatic environment. For cesium-134 the rate of uptake increased by increase of exposure time, while for cobalt-6o maximum uptake occurred after one day of exposure. The corresponding concentration factors at maximum uptake levels were 0.37 and 0.36 for cesium and cobalt respectively.The internal distribution of these radionuclides in the different tissues and organs of the fish due to uptake from the aquatic environment followed the decreasing order:For ¹³⁴Cs: muscle, bone, gills, stomach, kidneys, intestine and liver.For ⁶⁰Co: bone, muscle, gills, intestine, kidneys, stomach and liver.The internal distribution due to ingestion of these radionuclides followed nearly the same order as was found in case of uptake from the aquatic environment.     

Pressurized gas transport in two Japanese alder species in relation to their natural habitats

Oxygen uptake measurements have shown that pressurized gas transport, resulting from the physical effect of thermo-osmosis of gases, improves oxygen supply to the roots of the seedlings in two alder speciesAlnus japonica (Thunb.) Steud. andAlnus hirsuta (Spach) Rupr., which are both native in Japan. When gas transport conditions were established by irradiation of the tree stems the internal aeration was increased to a level nearly equal to the oxygen demand of the root system in leafless seedlings ofA. hirsuta, but was higher inA. japonica so that excess oxygen was excreted into the environment. An increase of superoxide dismutase (SOD) activity, which protects plants from toxic oxygen radicals and post-anoxic injury, has been observed in root tissues ofA. japonica when the seedlings were flooded for 3 days. The increase of SOD activity, in concert with high gas transport rates, may enable this tree species to grow in wet sites characterized by low oxygen partial pressure in the soil and by varying water tables. A less effective gas transport, flood-induced reduction of SOD activity in root tissues, and reduced height growth in waterlogged soil may be responsible for the fact thatA. hirsuta is unable to inhabit wettland sites.     

Study on energy transfer between carotenoid and chlorophyll a in cytochrome b 6 f complex from Bryopsis corticulans

The excitation energy transfer between carotenoid and chlorophyll (Chl) in the cytochrome b ₆ f complex from Bryopsis corticulans (B. corticulans), in which the carotenoid is 9-cis-α-carotene, was investigated by means of fluorescence excitation and sub-microsecond time-resolved absorption spectroscopies. The presence of efficient singlet excitation transfer from α-carotene to Chl a was found with an overall efficiency as high as ∼ ∼24%, meanwhile the Chl a-to-α-carotene triplet excitation transfer was also evidenced. Circular dichroism spectroscopy showed that α-carotene molecule existed in an asymmetric environment and Chl a molecule had a certain orientation in this complex.Bin-Xing Li and Ping Zuo contributed equally to this work.     

Differences in above- and below-ground responses to ozone between two populations of a perennial grass

Our study examined the influence of elevated ozone levels on the growth and mycorrhizal colonization of two populations of Elymus glaucus L. (blue wildrye). We hypothesized that ozone would reduce carbon availability to the plants, particularly below ground, and would affect mycorrhizal colonization. Because of the wide geographic range of E. glaucus, two populations of plants were selected from areas of contrasting ozone histories to examine intraspecies variation in response to ozone. Two populations of E. glaucus (southern California versus northern California) exposed in a factorial experiment involving ozone, mycorrhizal inoculation with Glomus intraradices Schenck and Smith, and plant source population. Ozone had a subtle effect on leaf area and number of tillers but did not affect overall root:shoot ratio in either population. The impact of ozone on above-ground growth characteristics was most pronounced in the southern population that came from a high-ozone environment, while below-ground responses such as reduced arbuscular colonization was most pronounced in the northern population which originated in a low-ozone environment. Further analysis of soil characteristics from the northern population of plants revealed a significant reduction in active soil bacterial biomass and an increase in total fungi per gram dry weight soil, suggesting a possible role for ozone in altering soil processes. Whether or not population differences in response to ozone were due to genetic shifts resulting from prior ozone remains to be determined. However, these subtle but important differences in population response to ozone above- and below-ground have significant implications in any attempt to generalize plant response, even within a species. Future research efforts need to include better characterization of intraspecific variation in response to ozone as well as possible adaptive strategies that may result from chronic ozone exposure.     

O-methylation of chlorinated phenols in the genus Rhodococcus

The ability to O-methylate chlorinated phenols and phenol derivatives in the genus Rhodococcus was studied. Several species and strains O-methylated chlorophenols to the corresponding anisoles, namely R. equi, R. erythropolis, R. rhodochrous, and Rhodococcus sp. strains P1 and An 117. The ability for a strain to O-methylate chlorophenols did not require that it had been isolated from an environment containing a chlorinated aromatic compound. O-methylation activity was stimulated by the presence of carbohydrate. All strains preferentially O-methylated a substrate with the hydroxyl group flanked by two chlorine substitunts.     

Enzyme function and polymorphism: A test in two Anolis lizard species

Electrophoretic surveys of two lizard species were used to test hypotheses that relate levels of enzyme variability to enzyme function (single-substrate versus multiple-substrate enzymes, regulatory versus nonregulatory enzymes). Anolis roquet behaviorally regulates its body temperature, but its congener A. gundlachi is passive to variations in the thermal environment. As a result, populations of A. gundlachi probably experience the thermal environment as temporally coarse-grained, whereas populations of A. roquet do not. We therefore predicted that A. gundlachi would exhibit greater enzyme heterozygosity than A. roquet and that different enzyme classes would contribute disproportionately to this interspecific difference. The data show (1) that A. gundlachi does have a higher heterozygosity and (2) that this difference appears to result from high levels of heterozygosity at loci coding for multiple-substrate enzymes. The dichotomy between regulatory and nonregulatory enzymes offers no explanation for the variability in heterozygosity among enzyme loci in these species.E.Z. was supported by a grant from the Natural Sciences and Engineering Council of Canada. The study was accomplished while P.E.H. held a postdoctoral fellowship from the Killam Trust of Dalhousie University and a grant from the Research Development Fund of Dalhousie University. The collection of material was made possible by grants (to P.E.H.) from National Science Foundation (DEB 75-16334), the Explorers Club of New York, Sigma Xi, and the Richmond and Anderson Funds of Harvard University. We thank Dr. D. W. Foltz for his help with the calculations.     

竞争强度变化对针阔混交林红松和水曲柳径向生长的影响

以3种间伐强度处理下(15%,30%和50%)针阔混交林内优势树种红松(Pinus koraiensis)和水曲柳(Fraxinus mandshurica)为研究对象,基于3次复测数据和树轮宽度数据分析不同间伐强度处理下红松和水曲柳的竞争变化特征,探讨竞争环境变化对保留木径向生长的影响。结果表明,1)红松保留木竞争环境发生变化的单木比例随着间伐强度增加而有所下降,但竞争减弱的保留木所占比例与间伐强度正相关,重度间伐样地内竞争减弱的红松保留木所占比例最大达到63%。不同间伐强度下水曲柳保留木竞争环境发生变化的单木比例一致,竞争减弱的单木比例占50%。2)不同竞争环境的水曲柳保留木径向生长趋势基本一致,而红松保留木径向生长变化趋势有所不同。轻度和重度间伐样地内竞争减弱的红松保留木径向生长在间伐后均呈上升趋势,而中度间伐样地内竞争减弱的红松保留木和各样地竞争不变的红松保留木以及不同竞争强度下水曲柳保留木均在2013年和2014年(间伐后2年内)出现生长抑制,而在2015年(伐后第3年)得到促进。3)随着间伐强度上升,自2015年(伐后第3年)竞争减弱的红松保留木径向生长年增量明显增加,显著...     

Partitioning the transplant site effect in reciprocal transplant experiments with Impatiens capensis and Impatiens pallida

Summary Modified reciprocal transplant experiments were conducted with the annual plant species Impatients capensis and I. pallida to partition the influence of environment on fitness into two components; that of (1) conspecific neighbours occupying each transplant site, and (2) the abiotic and biotic features of each site exclusive of the conspecific neighbours. In the within-species reciprocal transplant series, differences in survivorship and fruit production by cleistogamous flowers were attributable primarily to the effect of conspecific neighbours. In addition, plants surrounded by neighbours from the site of origin produced significantly more fruit from chasmogamous flowers compared with plants surrounded by neighbours from the alien site. In the between-species reciprocal transplant series, one transplant site was consistently associated with greater survivorship and fruit production regardless of the identity of neighbouring plants. The results suggest that different aspects of the environment in these reciprocal transplant experiments (conspecific neighbours, other species, physical factors) determine fitness in different situations.