The interactions of nanoparticles with the soft surfaces of biological systems like cells play key roles in executing their biomedical functions and in toxicity. The discovery or design of new biomedical functions, or the prediction of the toxicological consequences of nanoparticles in vivo, first require knowledge of the interplay processes of the nanoparticles with the target cells. This article focusses on the cellular uptake, location and translocation, and any biological consequences, such as cytotoxicity, of the most widely studied and used nanoparticles, such as carbon-based nanoparticles, metallic nanoparticles, and quantum dots. The relevance of the size and shape, composition, charge, and surface chemistry of the nanoparticles in cells is considered. The intracellular uptake pathways of the nanoparticles and the cellular responses, with potential signaling pathways activated by nanoparticle interactions, are also discussed.
HBsAg, the surface antigen of the hepatitis B virus (HBV), is used as a model to study the mechanisms and dynamics of a single-enveloped virus infecting living cells by imaging and tracking at the single-particle level. By monitoring the fluorescent indicator of HBsAg particles, it is found that HBsAg enters cells via a caveolin-mediated endocytic pathway. Tracking of individual HBsAg particles in living cells reveals the anomalously actin-dependent but not microtubule-dependent motility of the internalized HBsAg particle. The motility of HBsAg particles in living cells is also analyzed quantitatively. These results may settle the long-lasting debate of whether HBV directly breaks the plasma membrane barrier or relies on endocytosis to deliver its genome into the cell, and how the virus moves in the cell.
Water-soluble nano-C(60) can serve as a novel, effective, fluorescent sensing platform for biomolecular detection with high sensitivity and selectivity. In this paper, fluorescent detection of DNA and thrombin via nano-C(60) is demonstrated for the first time. The principle of the assay lies in the fact that the adsorption of the fluorescently labeled single-stranded DNA (ssDNA) probe by nano-C(60) leads to substantial fluorescence quenching. In the presence of a target, the biomolecular mutual interaction suppresses this quenching, signaling the existence of the target. This sensing system rivals graphene oxide but is superior to other carbon-structure-based systems. The present method can also achieve multiplex DNA detection and withstand the interference from human blood serum.
The moss Tayloria dubyi (Splachnaceae) is endemic to the subantarctic Magallanes ecoregion where it grows exclusively on bird dung and perhaps only on feces of the goose Chloephaga picta, a unique habitat among Splachnaceae. Some species of Splachnaceae from the Northern Hemisphere are known to recruit coprophilous flies as a vector to disperse their spores by releasing intense odors mimicking fresh dung or decaying corpses. The flies land on the capsule, and may get in contact with the protruding mass of spores that stick to the insect body. The dispersal strategy relies on the spores falling off when the insect reaches fresh droppings or carrion. Germination is thought to be rapid and a new population is quickly established over the entire substrate. The objectives of this investigation were to determine whether the coprophilous T. dubyi attracts flies and to assess the taxonomic diversity of the flies visiting this moss. For this, fly traps were set up above mature sporophyte bearing populations in two peatlands on Navarino Island. We captured 64 flies belonging to the Muscidae (Palpibracus chilensis), Tachinidae (Dasyuromyia sp) and Sarcophagidae (not identified to species) above sporophytes of T. dubyi, whereas no flies were captured in control traps set up above Sphagnum mats nearby.
Twigs from deciduous and coniferous living trees in Hungary were cut, incubated and examined selectively for the presence of a group of canopy fungi, the so-called "terrestrial aquatic hyphomycetes". Underwater incubation supplemented with aeration (the traditional method for aquatic hyphomycetes) was applied to observe sporulation in canopy fungi. Water was membrane-filtered and fungal elements trapped on the filters were stained and examined microscopically. Additionally the surface of the twigs was scraped for detection of sporulating structures. In total, 32 fungal species were detected on the twigs, 13 are described, a further 11 are identified to genus and eight are of unknown affinities. Two species, Retiarius bovicornutus and Tripospermum myrti, occurred on all tree species. The conidia of R. bovicornutus occurred in 85.2% of the samples but with greatly differring frequencies, with a maximum in spring. Conidiophores of R. bovicornutus, Trifurcospora irregularis and Trinacrium subtile were seen on twig surfaces. The numbers of species and conidia were higher on the twigs of evergreen trees than on those of deciduous trees. The greatest similarities in species composition were obtained between trees growing near each other. The highest indices of similarity (78.1; 55.4) occurred between Chamaecyparis and Juniperus. Fungal species composition on deciduous twigs after exposure in a stream from earlier studies and after incubation in distilled water are compared and discussed.
All known records of myxomycetes obtained during studies of these organisms carried out on La Réunion Island in the Indian Ocean are reported. The total includes 96 species and infraspecific taxa. Three of the specimens collected on the island could be identified only to genus, and 75 taxa are new records for the island. Seventy-eight species and infraspecific taxa are represented by specimens that fruited under natural conditions in the field, whereas 33 species and infraspecific taxa were obtained from moist chamber cultures. A new species (Diderma aurantiocolumellatum) is described and illustrated, and the data set for La Réunion Island is compared with data sets from several other islands and island groups for which the myxobiota is relatively well known.
The current state of knowledge about the genus Resupinatus in Greece is assessed. The genus is represented in Greece by three species: R. alboniger, R. applicatus and R. striatulus. Resupinatus alboniger is newly reported from Greece, whereas R. striatulus is reported for the second time. Detailed descriptions, line drawings and microscopic photographs are presented.
This paper describes a new Cymbella species from Lake Fuxian, Yunnan Plateau, China, based on both light and scanning electron microscopical investigations. The species, described as Cymbella fuxianensis Y.Li & Z.Gong sp. nov., has dorsiventral valves with a strongly arched dorsal margin and a ventral margin with a slightly gibbous central part. It has a narrow axial and central area with a lateral raphe that becomes filiform near the proximal and distal ends with indistinct stigmata on the ventral side of the central nodule. A comparison with similar Cymbella species is briefly discussed.
A new genus, Gesasha Abdel-Wahab & Nagahama, and three new species therein are described and illustrated from Gesashi mangroves, Okinawa, Japan. Molecular phylogenetic analyses of the partial SSU and LSU rDNA placed the three new species into a clade distantly related to morphologically similar fungi with a high statistical support in the Halosphaeriales, Sordariomycetidae, Sordariomycetes, Ascomycota. The new genus is characterized by hyaline to light-brown, immersed to erumpent coriaceous ascomata, persistent asci with a thickened apical pore with a cytoplasmic retraction below the ascus apex and uni or bi-celled, globose to widely ellipsoidal ascospores with or without ephemeral, amorphous polar to sub-polar appendages.
Four new species of the liverwort genus Bazzania (Lepidoziaceae) from tropical and subtropical eastern Australia (B. amblyphylla, B. fuhreri, B. gamscottii and B. tessellata) are described and illustrated.
Nine species of the cyanobacterial lichen families Lichinaceae and Gloeoheppiaceae are reported from South Korea, all of which are new to the Korean Peninsula. One specimen is identified as a possibly undescribed species of Pyrenopsis. Problems in species taxonomy, distribution patterns such as unusual long-distance disjunctions and floristic affinities are discussed.
Pohlia section Pohlia is taxonomically revised for Central and South America. Five species are recognized in the study area (P. cruda, P. elongata, P. longicollis, P. nutans, and P. oerstediana). Seven new synonyms are proposed. Pohlia leptopoda, Webera grammocarpa, and W. crassicostata from Brazil, P. rusbyana, and P. subleptopoda from Bolivia, and P. leptodontium from Colombia are synonyms of P. elongata. P. elatior from New Zealand is a synonym of P. nutans. Eight new lectotypes are designated. Pohlia oerstediana is a new record to South America and the extension ranges of Latin American species are presented. All Neotropical species of Section Pohlia are described and illustrated and distribution maps are given.
A new freshwater diatom, Fragilaria flexura sp. nov., was identified from light and scanning electron micrographs of sediment core material from a mountain lake in the Sredinny Mountains of Kamchatka Peninsula (Russia). Fragilaria flexura sp. nov. possesses an unique combination of morphological features, which allows its discrimination from previously identified, similar taxa such as Fragilaria cyclopum and Hannaea arcus. Fragilaria flexura sp. nov. is characterized by its valve outline, which is sickle-shaped and may or may not have a notch-like depression on the ventral margin, narrowly rounded ends and a very large, bilateral, hyaline central area. Fragilaria flexura sp. nov. seems to prefer meso-oligotrophic habitats.
A new species of Meliolinites (fossil Meliolales) is described from the Neogene sediments of Darjeeling foothills, West Bengal, India (Lower Siwalik, Gish Clay Formation, Middle Miocene to Upper Miocene).
A new species of Clitopilus sect. Clitopilus, viz. C. chrischonensis, is described on the basis of macro- and micromorphological characters, and of a ITS-LSU rDNA Bayesian phylogenetic analysis. A full description, taxonomic discussion on allied species, a photograph of fresh basidiomes and a photograph and line drawings of the most relevant microcharacters are provided.