Secondary pollen types characteristic of Louisiana honeys

Nine secondary pollen types (those comprising 16–45% of the pollen sample) were recovered from 54 honey samples (10 g) collected from the major beekeeping areas of Louisiana. The pollen types in order of decreasing importance are:Berchemia scandens, rattan vine;Rubus spp., blackberry and dewberry;Salix spp., willow;Trifolium repens, white clover;Glycine max, soybean;Parthenocissus quinquefolia, Virginia creeper; Rosaceae, rose family;Cephalanthus occidentalis, buttonbush; andCornus spp., dogwood. The first four secondary types also appeared as dominant pollen (over 45%) in some of the Louisiana honey samples investigated and were previously reported. The remaining five pollen types and the “bee plants” associated with each pollen type are identified and described.     

Pollen and organoleptic analysis of honeys in Leon province (Spain)

According to the pollen spectra recorded, most of them were monofloral (23) and 16 were multifloral. Erica honeys were the most abundant monofloral samples (9), Castanea sativa came next with 5; there were 3 samples of Helianthus annuus and 3 others of Lotus corniculatus and 1 of Rubus ulmifolius, Echium and Scrophularia canina pollen type respectively. The monofloral chestnuts honeys presented a minor pollen diversity. 108 pollen types were recorded, which belonged to 41 families. Fabaceae, Rosaceae and Ericaceae were the most represented families in the honeys studied. Cytisus scoparius and Rubus ulmifolius were the pollen types, which appeared in the highest number of samples. Certain pollen types such as Lavandula stoechas and Cistus ladanifer can be used as indicator or key elements in order to recognise the origin zone of honeys in the biogeographical Mediterranean region. As regards organoleptic analyses, most of our honeys (multiflorales, Erica, Rubus ulmifolius, Castanea sativa), samples are brown, not very sweet and present a homogeneous aspect, the other honeys have lighter colours, are sweeter and also have an homogeneous aspect (Helianthus annuus, Lotus corniculatus, Echium and Scrophularia canina -type).     

Pollen analysis of honeys from the Gharb region (NW Morocco)

The pollen spectra in 18 honey samples from the Gharb region (Northwest of Morocco) have been studied. The samples were collected directly from the beekeepers, both professional and amateurs. The results show that nectar was the main honey source in this region, although one forest or mixed honey was detected. Seven samples belonging to the Class I, five to the Class II and six to the Class III were found. In all the samples some honeydew indicator elements were detected, with HDEN/NPGN= 0.005-1.38. By the qualitative results 58 pollen types belonging to 28 families were identified. Some species of Lythrum , Eucalyptus , Trifolium , Citrus , Mentha , Apiaceae and Scrophulariaceae are the main nectar sources,and some of Asteraceae, Quercus sp., Olea europaea , Plantago sp. and Fragaria 2 ananassa are the most important pollen sources. At least 14 unifloral honeys (c. 77%) from Citrus , Eucalyptus , Lythrum , Mentha and Teucrium were detected.     

Pollen characterization of multifloral honeys from La Palma (Canary Islands)

The pollen content of twenty-five honey samples from twelve different apiaries on La Palma (Canary Islands) was subjected to qualitative and quantitative melissopalynological analysis. The quantitative analysis showed that 4% of the honey belonged to Maurizio Class II, 88% to Class III, 4% to Class IV and 4% to Class V. In the qualitative analysis, 60 pollen types were identified from 40 different families. The number of pollen types per honey sample ranges between 16 and 37 (mean of 25.8). Foeniculum vulgare-type and Rumex sp. pollen were present in all the samples. Castanea sativa and Echium plantagineum pollen were found in 96% of them and the combination Aspalathium bituminosum, Bidens pilosa-type and Erica arborea in 92%.     

Pollen analysis of honeys from Caatinga vegetation of the state of Bahia,Brazil

Based on pollen analysis, 17 honey samples collected in the Caatinga area from Nova Soure city were classified by botanical origin to identify the most important floral sources. Most of the honey samples were obtained in August and September. A total of 73 pollen types were identified belonging to 30 families, 64 genera and 30 species. The families best represented by their number of pollen types were Mimosaceae (11), Caesalpiniaceae (9), Rubiaceae and Fabaceae (5 each). Predominant pollen types were: Mimosa arenosa in four samples, M. sensitiva and M. tenuiflora in one sample. Pollen from Mimosa ursina was registered for the first time in the pollen spectrum of the Caatinga vegetation. The correspondence analysis showed a similarity among the honey samples based on pollen composition. The high representation of pollen from native species such as Chamaecrista nictitans, C. ramosa, C. swainsonii and Copaifera martii (Caesalpiniaceae); Aeschynomene martii and Zornia sericea (Fabaceae); Herissantia tiubae (Malvaceae); Mimosa arenosa, M. quadrivalvis, M. sensitiva, M. tenuiflora, M. ursina, Piptadenia moniliformis and Plathymenia reticulata (Mimosaceae), and Ziziphus joazeiro (Rhamnaceae) supports the origin of these honeys from Caatinga vegetation.     

Pollen spectra of different unifloral honeys from La Palma (Canary Islands,Spain)

The pollen content of twenty-four unifloral honey samples from twelve different apiaries in La Palma (Canary Islands) was subjected to qualitative and quantitative melissopalynological analysis. The quantitative analysis showed that 4% of the honey belonged to Maurizio's Class I, 8% to Class II, 58% to Class III, 17% to Class IV and 13% to Class V. According to the qualitative analysis, eight honeys were typified as unifloral of Castanea sativa , five of Carlina salicifolia , three of Echium brevirame , three of Reseda luteola , two of Erica arborea , two of Lotus hillebrandii and one of Lamiaceae Origanum vulgare ssp. virens -type. No honeydew elements were found. 62 pollen types were identified belonging to 42 different families. There is no pollen type common to all samples but Foeniculum vulgare -type is present in 22 of the samples (91.7%) and the combination Cistus sp., Erica arborea , Aspalthium bituminosum , Origanum vulgare ssp. virens -type and Rumex sp. in 21 (87.5%). The organoleptic analysis indicated that they are of good quality.     

Seasonal Incidence of Bacterial Temperature Types in Louisiana Soil and Water

Psychrophilic bacteria were not detected in soil, mud, and water in the summer. In winter, they were present in water and mud and constituted a significant portion of the bacterial flora in lake water.     

Pollen analysis of Apis dorsata Fabricius honeys in Bankura and Paschim Medinipur districts,West Bengal

One-hundred-and-five species corresponding to 38 families were identified through pollen analyses of 53 Apis dorsata honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently encountered were Fabaceae, Arecaceae, Asteraceae and Myrtaceae. Fabaceae had the greatest representation in number of pollen types (18 types), followed by Asteraceae (nine types), Cucurbitaceae (seven types), Lamiaceae and Myrtaceae (each with six types) and Malvaceae and Rutaceae (each with five types). Most of the honey samples correspond to class I. The presence of dominant pollen was detected in 18 samples. The predominant pollen types were Borassus flabellifer, Sesamum indicum (during summer), Eucalyptus globulus (during late autumn), Brassica nigra, Eucalyptus globulus (during winter) and Borassus flabellifer and Lannea coromandelica (during spring). The unifloral honeys obtained mostly during late autumn and winter were dominated by Eucalyptus globulus type. In monsoon and autumn unifloral honeys containing predominant pollen types (> 45%) were not found. However, according to frequency distribution the pollen types represented as very frequent were Peltophorum pterocarpum, Tridax procumbens (in monsoon) and Acacia auriculiformis, Cocos nucifera, Eucalyptus globulus, Tridax procumbens and Ziziphus mauritiana (in autumn). The seasonal diversity of pollen types obtained was at a maximum during spring (36 types) and minimum during late autumn (14 types). Seasonal variation in the number of pollen types per sample range from 5.86 ± 1.87 (during late autumn) to 6.86 ± 1.95 (during autumn) and exhibit low correlation (r = 0.31) with floral diversity. The diversity of pollen types per unifloral honey sample remains lower than multifloral honeys.     

Genotypic Analysis of Multidrug-Resistant Mycobacterium tuberculosis Isolates Recovered From Central China

DNA sequencing analysis was used to investigate genetic alterations in the rpoB, katG, and inhA regulatory region and embB in 66 Mycobacterium tuberculosis isolates recovered from Central China. Of the 36 multidrug-resistant isolates, 33 (92%) had mutations in the amplified region of rpoB. The most frequent mutation (58%, 19/36) was S531L (TCG→TTG). At least one mutation was found in the katG and inhA regulatory region in 83% (30/36) of the multidrug-resistant isolates, and mutations at katG codon 315 were identified in 78% (28/36). Alterations at embB306 may not confer resistance to EMB, and embB306 mutants were more frequently accompanied by rpoB mutations (100%, 16/16) than by katG 315 mutations (75%, 12/16). Our results show that geographic variation in the molecular genetic mechanism is responsible for drug resistance in multidrug-resistant M. tuberculosis. This observation will facilitate the development of a rapid molecular drug resistance screening approach for drug-resistant M. tuberculosis.     

Utility of Surface Pollen Assemblages to Delimit Eastern Eurasian Steppe Types

Modern pollen records have been used to successfully distinguish between specific prairie types in North America. Whether the pollen records can be used to detect the occurrence of Eurasian steppe, or even to further delimit various steppe types was until now unclear. Here we characterized modern pollen assemblages of meadow steppe, typical steppe and desert steppe from eastern Eurasia along an ecological humidity gradient. The multivariate ordination of the pollen data indicated that Eurasian steppe types could be clearly differentiated. The different steppe types could be distinguished primarily by xerophilous elements in the pollen assemblages. Redundancy analysis indicated that the relative abundances of Ephedra, Tamarix, Nitraria and Zygophyllaceae were positively correlated with aridity. The relative abundances of Ephedra increased from meadow steppe to typical steppe and desert steppe. Tamarix and Zygophyllaceae were found in both typical steppe and desert steppe, but not in meadow steppe. Nitraria was only found in desert steppe. The relative abundances of xerophilous elements were greater in desert steppe than in typical steppe. These findings indicate that Eurasian steppe types can be differentiated based on recent pollen rain.     

Soil Respiration at Dominant Patch Types within a Managed Northern Wisconsin Landscape

Soil respiration (SR), a substantial component of the forest carbon budget, has been studied extensively at the ecosystem, regional, continental, and global scales, but little progress has been made toward understanding SR over managed forest landscapes. Soil respiration is often influenced by soil temperature (T_s), soil moisture (M_s), and type of vegetation, and these factors vary widely among the patch types within a landscape. We measured SR, T_s, M_s, and litter depth (LD) during the 1999 and 2000 growing seasons within six dominant patch types (mature northern hardwoods, young northern hardwoods, clear-cuts, open-canopy Jack pine barrens, mature Jack pine, and mature red pine) on a managed forest landscape in northern Wisconsin, USA. We compared SR among and within the patch types and derived empirically based models that relate SR to T_s, M_s, and LD. Increased levels of soil moisture and higher temperatures in June–September 1999 may have accounted for the up to 37% overall higher SR than in this same period in 2000. In 2000, SR and T_s values were lower, and the sites may have been experiencing slight water limitations, but in general T_s was a much more accurate predictor of SR during this year. Empirical predictions of SR within each patch type derived from continuous T_s measurements were in close agreement with measured values of SR during 2000, but eight of 22 of the simulated values were significantly different ( = 0.05) from the rates measured in 1999. The young hardwoods consistently had the highest SR, whereas the pine barrens had the lowest. Results from our field studies and empirical models can help land managers assess landscape responses to potential disturbances and climatic changes.     

安徽烟草病毒类型及优势种初步研究

1978年,烟草病毒病在安徽烟区流行,导致凤阳县烟叶总产损失92.3％,引起了普遍震惊。1981—1984年作者对来自16个县、市552个病毒材料,经生物测定、血清反应、电镜观察,初步分离出CMV、TMV、PVY和PVX四种病毒。它们分别约占检测总数的82.79％、4.53％、2.54％和0.36％,其中CMV与长期视为优势种的TMV比值为18.3,除此,尚有约占检测总数9.8％的CMV和TMV、CMV和PVY复合侵染,以及不明类型的毒株。通过对田间烟草以及其他植物花叶病株的实际检测,进一步表明:CMV在烟区分布范围极广、出现频次最多,已形成了复杂的循环侵染系统,成为近期内烟草病毒病持续流行危害的首要毒原。     

From early pollen trapping experiments to the Pollen Monitoring Programme

Pollen monitoring has become a standard investigation method for researchers in several disciplines; among them are Quaternary palynologists, who conduct experiments in order to gain insights that will help to interpret the content of pollen in sediments. A review of the literature shows how these experiments diversified during the 1920s and 1930s with an array of different research questions, ranging from pollination biology to hay fever studies. Quaternary palynologists gained renewed interest with the possibility of radiocarbon dating late Quaternary sediments and obtaining accumulation rates. Also, the comprehensive model of pollen deposition and the pollen budget studies by H. Tauber encouraged researchers to conduct similar experiments using the same type of pollen trap, which became the main trapping device for Quaternary palynologists. The high precipitation in the tropics inspired the development of alternative designs. The equipment used to assess the pollen content in the air has evolved from simple gravity devices to different types of apparatus using a vacuum pump or revolving rods that collect the pollen on impact. Silicone impregnated filters exposed perpendicularly to the wind can also yield a volumetric assessment and have proven useful in areas with a low content of pollen in the air. The literature review is followed by a brief account of the developments which established the basis for the formation of a group of scientists monitoring the pollen deposition at a network of sites using standard pollen traps, the Pollen Monitoring Programme (PMP). Over the last 15 years the network has collected a large dataset, which is now available to answer a number of research questions. A summary of selected regions and environments, for which pollen monitoring results are available, is provided to serve as a complement to the investigations mentioned above and to provide an overview that may stimulate new research.     

香梨杂种后代花粉发育类型及其花药的解剖学研究

对4个组合35个香梨F1代单株的花粉发育状况进行了考察,并结合花粉量调查对F1代群体的典型单株进行了花药解剖研究。结果表明:(1)香梨杂种后代的花粉发育类型大致可分为3种类型,即正常发育型、少粒空壳型和完全败育型,其中雄性不育类型(少粒空壳型和完全败育型)占到整个杂交后代株系的42.8%。(2)花药解剖观察显示导致花粉空粒化进而完全解体的主要原因是药壁组织的异常发育。推测梨的雄性不育性可能受1对纯合的隐性基因控制,人为杂交导致的基因重组使隐性基因纯合后在杂交后代中高频率表达;同时发现,其花粉发育也受环境影响,树体的营养状况可影响花粉的发育进程。     

Guanine-Rich Sequences Are a Dominant Feature of Exosomal microRNAs across the Mammalian Species and Cell Types

Exosome is an extracellular vesicle released from multivesicular endosomes and contains micro (mi) RNAs and functional proteins derived from the donor cells. Exosomal miRNAs act as an effector during communication with appropriate recipient cells, this can aid in the utilization of the exosomes in a drug delivery system for various disorders including malignancies. Differences in the miRNA distribution pattern between exosomes and donor cells indicate the active translocation of miRNAs into the exosome cargos in a miRNA sequence-dependent manner, although the molecular mechanism is little known. In this study, we statistically analyzed the miRNA microarray data and revealed that the guanine (G)-rich sequence is a dominant feature of exosome-dominant miRNAs, across the mammalian species-specificity and the cell types. Our results provide important information regarding the potential use of exosome cargos to develop miRNA-based drugs for the treatment of human diseases.     

Pollen grains in honeys produced by Tetragonisca angustula (Latreille, 1811) (Hymenoptera: Apidae) in tropical semi-arid areas of north-eastern Brazil

The flora of north-eastern Brazil offers a source of nectariferous–polliniferous species that support many native pollinators. However, few studies have examined the plant–Meliponini interaction, especially from the melissopalynological aspect. We assessed the flora exploited by Tetragonisca angustula in two caatinga (dry vegetation) areas in the Brazilian semi-arid region through pollen analysis of honeys with the goal of answering the following questions: (a) What are the most representative pollens found in the honeys? (b) Do certain pollen types function as regional geographic markers? (c) What are the characteristics of the trophic niche of T. angustula in these areas? The honeys (n = 27) were collected every month from October 2010 to December 2011 in Itaberaba and Ruy Barbosa, diluted in tepid water and 95 % ethanol and subsequently acetolysed. The results revealed 67 pollen types in the honeys, with 25 common to both study areas and most of them belonging to the family Fabaceae (>10 types). The most frequent pollen types were Heteropterys, Mikania, Myrcia, Prosopis juliflora and Solanum for Itaberaba and Heteropterys, Mimosa tenuiflora, P. juliflora, Schinus, Senna macranthera, Solanum and Syagrus coronata for Ruy Barbosa. Anadenanthera colubrina, Poincianella pyramidalis and Ziziphus joazeiro were considered markers for caatinga flora. The amplitude of the trophic niche varied between 0.36 and 2.55, while the evenness ranged from 0.15 to 0.77, characterising the foraging habit of T. angustula as polylectic with a more homogeneous use of the flora in Ruy Barbosa than in Itaberaba.     

Cytopathology of Anthers and Pollen From Lettuce Plants Infected by Lettuce Mosaic Virus

Thin sections of mature anthers and pollen grains from three lettuce (Lactuca sativa) plants infected with lettuce mosaic potyvirus (LMV) were studied by immunogold labelling. Labelled LMV particles were present externally on the exine of pollen grains from all plants, but were observed internally in the pollen grains from only one plant. Within mature pollen grains the virus particles were associated with the cytoplasmic bundle inclusions typical of infection by potyviruses. The tapetal plasmodium and the epidermal and endothecial layers of mature anthers from all infected plants also contained labelled virus particles, together with pinwheel and bundle inclusions.     

From Rare to Dominant: a Fine-Tuned Soil Bacterial Bloom during Petroleum Hydrocarbon Bioremediation

Hydrocarbons are worldwide-distributed pollutants that disturb various ecosystems. The aim of this study was to characterize the short-lapse dynamics of soil microbial communities in response to hydrocarbon pollution and different bioremediation treatments. Replicate diesel-spiked soil microcosms were inoculated with either a defined bacterial consortium or a hydrocarbonoclastic bacterial enrichment and incubated for 12 weeks. The microbial community dynamics was followed weekly in microcosms using Illumina 16S rRNA gene sequencing. Both the bacterial consortium and enrichment enhanced hydrocarbon degradation in diesel-polluted soils. A pronounced and rapid bloom of a native gammaproteobacterium was observed in all diesel-polluted soils. A unique operational taxonomic unit (OTU) related to the Alkanindiges genus represented ∼0.1% of the sequences in the original community but surprisingly reached >60% after 6 weeks. Despite this Alkanindiges-related bloom, inoculated strains were maintained in the community and may explain the differences in hydrocarbon degradation. This study shows the detailed dynamics of a soil bacterial bloom in response to hydrocarbon pollution, resembling microbial blooms observed in marine environments. Rare community members presumably act as a reservoir of ecological functions in high-diversity environments, such as soils. This rare-to-dominant bacterial shift illustrates the potential role of a rare biosphere facing drastic environmental disturbances. Additionally, it supports the concept of “conditionally rare taxa,” in which rareness is a temporary state conditioned by environmental constraints.