Turning Up the Heat on a Hotspot: DNA Barcodes Reveal 80% More Species of Geometrid Moths along an Andean Elevational Gradient

We sampled 14,603 geometrid moths along a forested elevational gradient from 1020–3021 m in the southern Ecuadorian Andes, and then employed DNA barcoding to refine decisions on species boundaries initially made by morphology. We compared the results with those from an earlier study on the same but slightly shorter gradient that relied solely on morphological criteria to discriminate species. The present analysis revealed 1857 putative species, an 80% increase in species richness from the earlier study that detected only 1010 species. Measures of species richness and diversity that are less dependent on sample size were more than twice as high as in the earlier study, even when analysis was restricted to an identical elevational range. The estimated total number of geometrid species (new dataset) in the sampled area is 2350. Species richness at single sites was 32–43% higher, and the beta diversity component rose by 43–51%. These impacts of DNA barcoding on measures of richness reflect its capacity to reveal cryptic species that were overlooked in the first study. The overall results confirmed unique diversity patterns reported in the first investigation. Species diversity was uniformly high along the gradient, declining only slightly above 2800 m. Species turnover also showed little variation along the gradient, reinforcing the lack of evidence for discrete faunal zones. By confirming these major biodiversity patterns, the present study establishes that incomplete species delineation does not necessarily conceal trends of biodiversity along ecological gradients, but it impedes determination of the true magnitude of diversity and species turnover.     

Self-assembly of sensory neurons into ganglia-like microtissues

Unraveling intra- and inter-cellular signaling networks managing cell-fate control, coordinating complex differentiation regulatory circuits and shaping tissues and organs in living systems remain major challenges in the post-genomic era. Resting on the laurels of past-century monolayer culture technologies, the cell culture community has only recently begun to appreciate the potential of three-dimensional mammalian cell culture systems to reveal the full scope of mechanisms orchestrating the tissue-like cell quorum in space and time. Capitalizing on gravity-enforced self-assembly of monodispersed primary embryonic mouse cells in hanging drops, we designed and characterized a three-dimensional cell culture model for ganglion-like structures. Within 24h, a mixture of mouse embryonic fibroblasts (MEF) and cells, derived from the dorsal root ganglion (DRG) (sensory neurons and Schwann cells) grown in hanging drops, assembled to coherent spherical microtissues characterized by a MEF feeder core and a peripheral layer of DRG-derived cells. In a time-dependent manner, sensory neurons formed a polar ganglion-like cap structure, which coordinated guided axonal outgrowth and innervation of the distal pole of the MEF feeder spheroid. Schwann cells, present in embryonic DRG isolates, tended to align along axonal structures and myelinate them in an in vivo-like manner. Whenever cultivation exceeded 10 days, DRG:MEF-based microtissues disintegrated due to an as yet unknown mechanism. Using a transgenic MEF feeder spheroid, engineered for gaseous acetaldehyde-inducible interferon-beta (ifn-beta) production by cotransduction of retro-/ lenti-viral particles, a short 6-h ifn-beta induction was sufficient to rescue the integrity of DRG:MEF spheroids and enable long-term cultivation of these microtissues. In hanging drops, such microtissues fused to higher-order macrotissue-like structures, which may pave the way for sophisticated bottom-up tissue engineering strategies. DRG:MEF-based artificial micro- and macrotissue design demonstrated accurate key morphological aspects of ganglions and exemplified the potential of self-assembled scaffold-free multicellular micro-/macrotissues to provide new insight into organogenesis.     

A dynamic mass balance model for phosphorus fluxes and concentrations in coastal areas

This paper presents a general, process-based mass balance model (CoastMab) for total phosphorus (TP) in defined coastal areas (at the ecosystem scale). The model is based on ordinary differential equations and calculates inflow, outflow and internal fluxes on a monthly basis. It consists of four compartments: surface water, deep water, erosion/transportation areas for fine sediments and accumulation areas for fine sediments. The separation between surface water and deep water is not done based on water temperature, but on sedimentological criteria instead (from the theoretical wave base). There are algorithms for all major internal TP fluxes (sedimentation, resuspension, diffusion, mixing and burial). Validations were performed using data from 21 different Baltic coastal areas. The results show that the model predicts monthly TP in water and chlorophyll a very well (generally within the uncertainty bands of the empirical data). The model has also been put through sensitivity tests, which show that the most important factor regulating the predictions of the model is generally the TP concentration in the sea beyond the coast. The model is simple to apply, since all driving variables may be accessed from maps or monitoring programs. The driving variables include coastal area, section area (between the defined coastal area and the adjacent sea), mean and maximum depths, latitude (used to predict water temperatures, stratification and mixing), salinity and TP concentration in the sea. Many of the model structures are general and could be used for areas other than those included in this study, e.g., for open coasts, estuaries or tidal coasts, as well as for other substances than phosphorus.     

Seasonal distribution and dive behaviour of harp seals (<Emphasis Type="Italic">Pagophilus groenlandicus</Emphasis>) of the White Sea–Barents Sea stock

Eight adult female harp seals (Pagophilus groenlandicus) of the White Sea–Barents Sea stock were tagged with satellite-linked dive recorders during the nursing period and followed from breeding in late February 1995 until moulting in late April 1995. Another ten adult harp seals of both sexes were tagged and followed from moult in early May 1996 until breeding in late February the following year. Between breeding and moult the seals were distributed along the coasts of Kola of Russia and eastern Finnmark of Norway, coinciding in time and space with the spawning capelin (Mallotus villosus). Between moulting and breeding they encircled the entire Barents Sea, mostly in open water, using the water column from 20 to 300 m, and in so doing by and large reflecting the annual migrations of the capelin. Capelin is therefore assumed to be the main source of prey for the White Sea–Barents Sea stock of harp seals, to be substituted, in part, by amphipods (e.g. Themisto libellula) in mid-summer and polar cod (Boreogadus saida) and herring (Clupea pallasii) in late autumn and winter. These data provide a baseline for the evaluation of the effects of future climatic change in the rich Barents Sea ecosystem.     

Use of a fluorescence labelled,carbohydrate-binding module from Phanerochaete chrysosporium Cel7D for studying wood cell wall ultrastructure

The -amino group of the carbohydrate-binding module (CBM) from Phanerochaete chrysosporium cellulase Cel7D was covalently labelled with fluorescein isothiocyanate. The fluorescein-labelled CBM was characterised regarding substrate binding, showing specificity only to cellulose and not to mannan and xylan. Conjugation of fluorescein isothiocyanate to CBM did not affect its binding to cellulose. The labelled CBM was successfully used as a probe for detecting cellulose in lignocellulose material such as never dried spruce and birch wood as well as pulp fibres.     

Cytochemical localization of 5′-nucleotidase in the enteric ganglia and in smooth muscle cells of the guinea-pig

Brain Cell Biology - Cytochemical techniques were used to study the localization of 5′-nucleotidase in the enteric ganglia and in smooth muscle cells of the guinea-pig ileum, iris and vas...     

Floral scent in dioeciousSalix (Salicaceae)—a cue determining the pollination system?

Floral scents of male and female inflorescences of three dioeciousSalix species were collected by head-space adsorption, and analysed by GC-MS. InSalix caprea andS. cinerea 1,4-dimethoxy benzene was the main compound, and male and female scents showed a high degree of resemblance. No dominant compound was found inS. repens and malefemale scent similarity was low. Floral scent inSalix is likely a strong orientation cue, guiding pollinators between male and female plants ensuring pollen transfer and pollination. We suggest that a high degree of male-female floral scent resemblance is coupled to a high degree of insect pollination. Floral scent does not promote reproductive isolation betweenS. caprea andS. cinerea.     

Two-tier vessel for photoautotrophic high-density cultures

Two-tier vessels, developed for culturing of microalgae and cyanobacteria at high cell density on a shaken platform, were assembled from a flat lower chamber to be filled with a CO₂ buffer and an upper flat sterile chamber for the culture that was separated from the lower chamber by a porous polypropylene membrane. Diffusive gas exchange with the atmosphere was controlled by the O₂ outlet channel. Referred to surface area, rates of CO₂ transfer to a shaken weakly alkaline buffer solution across the membrane were higher than those reached on the conventional pathway through the free upper liquid surface. Membrane-mediated CO₂ supply enabled rapid growth of Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7002 up to ultrahigh cell density. The biomass (dry weight) concentration of Synechococcus cultures reached more than 30 g L^?1 on a buffered medium with adequate concentrations of mineral nutrients. An increase of 15 to 20 g L^?1 was observed during repeated two-day cycles. Separate pathways for CO₂ supply and oxygen outlet prevented significant loss of CO₂. Convective gas flow through the oxygen outlet channel enabled the estimation of the O₂ generation rate. The permeability of the channel for diffusive O₂/N₂ exchange limited the O₂ concentration to a moderate value. It is concluded that shaken flat cultures using CO₂ supply through a porous hydrophobic membrane and diffusive release of O₂ through a separate pathway are promising for research on microalgae and cyanobacteria.     

Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands

Background

EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI study found that low frequency band (theta and alpha) activity negatively correlated with the BOLD signal during the retention phase of a WM task. However, the coupling of higher (beta and gamma) frequencies with the BOLD signal during WM is unknown.

Methodology

In 16 healthy adult subjects, we first investigated EEG-BOLD signal correlations for theta (5–7 Hz), alpha1 (8–10), alpha2 (10–12 Hz), beta1 (13–20), beta2 (20–30 Hz), and gamma (30–40 Hz) during the retention period of a WM task with set size 2 and 5. Secondly, we investigated whether load sensitive brain regions are characterised by effects that relate frequency bands to BOLD signals effects.

Principal Findings

We found negative theta-BOLD signal correlations in the MPFC, PPC, and cingulate cortex (ACC and PCC). For alpha1 positive correlations with the BOLD signal were found in ACC, MPFC, and PCC; negative correlations were observed in DLPFC, PPC, and inferior frontal gyrus (IFG). Negative alpha2-BOLD signal correlations were observed in parieto-occipital regions. Beta1-BOLD signal correlations were positive in ACC and negative in precentral and superior temporal gyrus. Beta2 and gamma showed only positive correlations with BOLD, e.g., in DLPFC, MPFC (gamma) and IFG (beta2/gamma). The load analysis revealed that theta and—with one exception—beta and gamma demonstrated exclusively positive load effects, while alpha1 showed only negative effects.

Conclusions

We conclude that the directions of EEG-BOLD signal correlations vary across brain regions and EEG frequency bands. In addition, some brain regions show both load sensitive BOLD and frequency band effects. Our data indicate that lower as well as higher frequency brain oscillations are linked to neurovascular processes during WM.