A direct PCR approach with low-biomass insert opens new horizons for molecular sciences on cryptogam communities.

Molecular sequence data have transformed research on cryptogams (e.g., lichens, microalgae, fungi, and symbionts thereof) but methods are still strongly hampered by the small size and intermingled growth of the target organisms, poor cultivability and detrimental effects of their secondary metabolites. Here, we aim to showcase examples on which a modified direct PCR approach for diverse aspects of molecular work on environmental samples concerning biocrusts, biofilms, and cryptogams gives new options for the research community. Unlike traditional approaches, this methodology only requires biomass equivalent to colonies and fragments of 0.2 mm in diameter, which can be picked directly from the environmental sample, and includes a quick DNA lysis followed by a standardized PCR cycle that allows co-cycling of various organisms/target regions in the same run. We demonstrate that this modified method can (i) amplify the most widely used taxonomic gene regions and those used for applied and environmental sciences from single colonies and filaments of free-living cyanobacteria, bryophytes, fungi, and lichens, including their mycobionts, chlorobionts, and cyanobionts from both isolates and in situ material during co-cycling; (ii) act as a tool to confirm that the dominant lichen photobiont was isolated from the original sample; and (iii) optionally remove inhibitory secondary lichen substances. Our results represent examples which highlight the method's potential for future applications covering mycology, phycology, biocrusts, and lichenology, in particular.IMPORTANCECyanobacteria, green algae, lichens, and other cryptogams play crucial roles in complex microbial systems such as biological soil crusts of arid biomes or biofilms in caves. Molecular investigations on environmental samples or isolates of these microorganisms are often hampered by their dense aggregation, small size, or metabolism products which complicate DNA extraction and subsequent PCRs. Our work presents various examples of how a direct DNA extraction and PCR method relying on low biomass inserts can overcome these common problems and discusses additional applications of the workflow including adaptations.

Surprise: Unexpected Action Execution and Unexpected Inhibition Recruit the Same Fronto-Basal-Ganglia Network.

Unexpected and thus surprising events are omnipresent and oftentimes require adaptive behavior such as unexpected inhibition or unexpected action. The current theory of unexpected events suggests that such unexpected events just like global stopping recruit a fronto-basal-ganglia network. A global suppressive effect impacting ongoing motor responses and cognition is specifically attributed to the subthalamic nucleus (STN). Previous studies either used separate tasks or presented unexpected, task-unrelated stimuli during response inhibition tasks to relate the neural signature of unexpected events to that of stopping. Here, we aimed to test these predictions using a within task design with identical stimulus material for both unexpected action and unexpected inhibition using functional magnetic resonance imaging (fMRI) for the first time. To this end, 32 healthy human participants of both sexes performed a cue-informed go/nogo task comprising expected and unexpected action and inhibition trials during fMRI. Using conjunction, contrast, and Bayesian analyses, we demonstrate that unexpected action elicited by an unexpected go signal and unexpected inhibition elicited by an unexpected nogo signal recruited the same fronto-basal-ganglia network which is usually assigned to stopping. Furthermore, the stronger the unexpected action-related activity in the STN region was the more detrimental was the effect on response times. The present results thus complement earlier findings and provide direct evidence for the unified theory of unexpected events while ruling out alternative task and novelty effects.SIGNIFICANCE STATEMENT This is the first study using functional magnetic resonance imaging (fMRI) to test whether unexpected events regardless of whether they require unexpected action or inhibition recruit a fronto-basal-ganglia network just like stopping. In contrast to previous studies, we used identical stimulus material for both conditions within one task. This enabled us to directly test predictions of the current theory of unexpected events and, moreover, to test for condition-specific neural signatures. The present results underpin that both processes recruit the same neural network while excluding alternative task and novelty effects. The simple task design thus provides an avenue to studying surprise as a pure form of reactive inhibition in neuropsychiatric patients displaying inhibitory deficits who often have a limited testing capacity.

Shifting Boundaries: Ecological and Geographical Range extension Based on Three New Species in the Cyanobacterial Genera Cyanocohniella, Oculatella, and, Aliterella.

The polyphasic approach has been widely applied in cyanobacterial taxonomy, which frequently led to additions to the species inventory. Increasing our knowledge about species and the habitats they were isolated from enables new insights into the ecology of newly established genera and species allowing speculations about the ecological niche of taxa. Here, we are describing three new species belonging to three genera that broadens the ecological amplitude and the geographical range of each of the three genera. Cyanocohniella crotaloides sp. nov. is described from sandy beach mats of the temperate island Schiermonnikoog, Netherlands, Oculatella crustae-formantes sp. nov. was isolated from biological soil crusts of the Arctic Spitsbergen, Norway, and Aliterella chasmolithica originated from granitic stones of the arid Atacama Desert, Chile. All three species could be separated from related species using molecular sequencing of the 16S rRNA gene and 16S-23S ITS gene region, the resulting secondary structures as well as p-distance analyses of the 16S-23S ITS and various microscopic techniques. The novel taxa described in this study contribute to a better understanding of the diversity of the genera Cyanocohniella, Oculatella, and Aliterella in different habitats.

Water availability shapes edaphic and lithic cyanobacterial communities in the Atacama Desert.

In the Atacama Desert, cyanobacteria grow on various substrates such as soils (edaphic) and quartz or granitoid stones (lithic). Both edaphic and lithic cyanobacterial communities have been described but no comparison between both communities of the same locality has yet been undertaken. In the present study, we compared both cyanobacterial communities along a precipitation gradient ranging from the arid National Park Pan de Azúcar (PA), which resembles a large fog oasis in the Atacama Desert extending to the semiarid Santa Gracia Natural Reserve (SG) further south, as well as along a precipitation gradient within PA. Various microscopic techniques, as well as culturing and partial 16S rRNA sequencing, were applied to identify 21 cyanobacterial species; the diversity was found to decline as precipitation levels decreased. Additionally, under increasing xeric stress, lithic community species composition showed higher divergence from the surrounding edaphic community, resulting in indigenous hypolithic and chasmoendolithic cyanobacterial communities. We conclude that rain and fog water, respectively, cause contrasting trends regarding cyanobacterial species richness in the edaphic and lithic microhabitats.

Neural Architecture of Selective Stopping Strategies: Distinct Brain Activity Patterns Are Associated with Attentional Capture But Not with Outright Stopping.

In stimulus-selective stop-signal tasks, the salient stop signal needs attentional processing before genuine response inhibition is completed. Differential prefrontal involvement in attentional capture and response inhibition has been linked to the right inferior frontal junction (IFJ) and ventrolateral prefrontal cortex (VLPFC), respectively. Recently, it has been suggested that stimulus-selective stopping may be accomplished by the following different strategies: individuals may selectively inhibit their response only upon detecting a stop signal (independent discriminate then stop strategy) or unselectively whenever detecting a stop or attentional capture signal (stop then discriminate strategy). Alternatively, the discrimination process of the critical signal (stop vs attentional capture signal) may interact with the go process (dependent discriminate then stop strategy). Those different strategies might differentially involve attention- and stopping-related processes that might be implemented by divergent neural networks. This should lead to divergent activation patterns and, if disregarded, interfere with analyses in neuroimaging studies. To clarify this crucial issue, we studied 87 human participants of both sexes during a stimulus-selective stop-signal task and performed strategy-dependent functional magnetic resonance imaging analyses. We found that, regardless of the strategy applied, outright stopping displayed indistinguishable brain activation patterns. However, during attentional capture different strategies resulted in divergent neural activation patterns with variable activation of right IFJ and bilateral VLPFC. In conclusion, the neural network involved in outright stopping is ubiquitous and independent of strategy, while different strategies impact on attention-related processes and underlying neural network usage. Strategic differences should therefore be taken into account particularly when studying attention-related processes in stimulus-selective stopping.SIGNIFICANCE STATEMENT Dissociating inhibition from attention has been a major challenge for the cognitive neuroscience of executive functions. Selective stopping tasks have been instrumental in addressing this question. However, recent theoretical, cognitive and behavioral research suggests that different strategies are applied in successful execution of the task. The underlying strategy-dependent neural networks might differ substantially. Here, we show evidence that, regardless of the strategy used, the neural network involved in outright stopping is ubiquitous. However, significant differences can only be found in the attention-related processes underlying those different strategies. Thus, when studying attentional processing of salient stop signals, strategic differences should be considered. In contrast, the neural networks implementing outright stopping seem less or not at all affected by strategic differences.

Structural insights into the inactive subunit of the apicoplast-localized caseinolytic protease complex of Plasmodium falciparum.

The ATP-dependent caseinolytic protease, ClpP, is highly conserved in bacteria and in the organelles of different organisms. In cyanobacteria, plant plastids, and the apicoplast of the genus Plasmodium, a noncatalytic paralog of ClpP, termed ClpR, has been identified. ClpRs are found to form heterocomplexes with ClpP resulting in a ClpRP tetradecameric cylinder having less than 14 catalytic triads. The exact role of ClpR in such a complex remains enigmatic. Here we describe the x-ray crystal structure of ClpR protein heptamer from Plasmodium falciparum (PfClpR). This is the first structure of a ClpR protein. The structure shows that the PfClpR monomer adopts a fold similar to that of ClpP, but has a unique motif, which we named the R-motif, forming a ß turn located near the inactive catalytic triad in a three-dimensional space. The PfClpR heptamer exhibits a more open and flat ring than a ClpP heptamer. PfClpR was localized in the P. falciparum apicoplast as is the case of PfClpP. However, biochemical and structural data suggest that, contrary to what has been observed in other organisms, PfClpP and PfClpR do not form a stable heterocomplex in the apicoplast of P. falciparum.

Structure, gene composition, divergence time and phylogeny analysis of the woody desert species Neltuma alba, Neltuma chilensis and Strombocarpa strombulifera.

Neltuma alba (Algarrobo blanco), Neltuma chilensis (Algarrobo Chileno) and Strombocarpa strombulifera (Fortuna) are some of the few drought resistant trees and shrubs found in small highly fragmented populations, throughout the Atacama Desert. We reconstructed their plastid genomes using de novo assembly of paired-end reads from total genomic DNA. We found that the complete plastid genomes of N. alba and N. chilensis are larger in size compared to species of the Strombocarpa genus. The Strombocarpa species presented slightly more GC content than the Neltuma species. Therefore, we assume that Strombocarpa species have been exposed to stronger natural selection than Neltuma species. We observed high variation values in the number of cpSSRs (chloroplast simple sequence repeats) and repeated elements among Neltuma and Strombocarpa species. The p-distance results showed a low evolutionary divergence within the genus Neltuma, whereas a high evolutionary divergence was observed between Strombocarpa species. The molecular divergence time found in Neltuma and Strombocarpa show that these genera diverged in the late Oligocene. With this study we provide valuable information about tree species that provide important ecosystem services in hostile environments which can be used to determine these species in the geographically isolated communities, and keep the highly fragmented populations genetically healthy.

The dark side of orange: Multiorganismic continuum dynamics within a lichen of the Atacama Desert.

Over the decades our understanding of lichens has shifted to the fact that they are multiorganismic, symbiotic microecosystems, with their complex interactions coming to the fore due to recent advances in microbiomics. Here, we present a mutualistic-parasitic continuum dynamics scenario between an orange lichen and a lichenicolous fungus from the Atacama Desert leading to the decay of the lichen's photobiont and leaving behind a black lichen thallus. Based on isolation, sequencing, and ecophysiological approaches including metabolic screenings of the symbionts, we depict consequences upon infection with the lichenicolous fungus. This spans from a loss of the lichen's photosynthetic activity and an increased roughness of its surface to an inhibition of the parietin synthesis as a shared pathway between the photobiont and the mycobiont, including a shift of secondary metabolism products. This degree of relations has rarely been documented before, although lichenicolous fungi have been studied for over 200 years, adding an additional level to the view of interactions within lichens.

The underestimated fraction: diversity, challenges and novel insights into unicellular cyanobionts of lichens.

Lichens are remarkable and classic examples of symbiotic organisms that have fascinated scientists for centuries. Yet, it has only been for a couple of decades that significant advances have focused on the diversity of their green algal and/or cyanobacterial photobionts. Cyanolichens, which contain cyanobacteria as their photosynthetic partner, include up to 10% of all known lichens and, as such, studies on their cyanobionts are much rarer compared to their green algal counterparts. For the unicellular cyanobionts, i.e. cyanobacteria that do not form filaments, these studies are even scarcer. Nonetheless, these currently include at least 10 different genera in the cosmopolitan lichen order Lichinales. An international consortium (International Network of CyanoBionts; INCb) will tackle this lack of knowledge. In this article, we discuss the status of current unicellular cyanobiont research, compare the taxonomic resolution of photobionts from cyanolichens with those of green algal lichens (chlorolichens), and give a roadmap of research on how to recondition the underestimated fraction of symbiotic unicellular cyanobacteria in lichens.

Spatiotemporal dynamics of bimanual integration in human somatosensory cortex and their relevance to bimanual object manipulation.

Little is known about the spatiotemporal dynamics of cortical responses that integrate slightly asynchronous somatosensory inputs from both hands. This study aimed to clarify the timing and magnitude of interhemispheric interactions during early integration of bimanual somatosensory information in different somatosensory regions and their relevance for bimanual object manipulation and exploration. Using multi-fiber probabilistic diffusion tractography and MEG source analysis of conditioning-test (C-T) median nerve somatosensory evoked fields in healthy human subjects, we sought to extract measures of structural and effective callosal connectivity between different somatosensory cortical regions and correlated them with bimanual tactile task performance. Neuromagnetic responses were found in major somatosensory regions, i.e., primary somatosensory cortex SI, secondary somatosensory cortex SII, posterior parietal cortex, and premotor cortex. Contralateral to the test stimulus, SII activity was maximally suppressed by 51% at C-T intervals of 40 and 60 ms. This interhemispheric inhibition of the contralateral SII source activity correlated directly and topographically specifically with the fractional anisotropy of callosal fibers interconnecting SII. Thus, the putative pathway that mediated inhibitory interhemispheric interactions in SII was a transcallosal route from ipsilateral to contralateral SII. Moreover, interhemispheric inhibition of SII source activity correlated directly with bimanual tactile task performance. These findings were exclusive to SII. Our data suggest that early interhemispheric somatosensory integration primarily occurs in SII, is mediated by callosal fibers that interconnect homologous SII areas, and has behavioral importance for bimanual object manipulation and exploration.

Roccellinastrum, Cenozosia and Heterodermia: Ecology and phylogeny of fog lichens and their photobionts from the coastal Atacama Desert.

Some deserts on Earth such as the Namib or the Atacama are influenced by fog which can lead to the formation of local fog oases - unique environments hosting a great diversity of specialized plants and lichens. Lichens of the genera Ramalina, Niebla or Heterodermia have taxonomically been investigated from fog oases around the globe but not from the Atacama Desert, one of the oldest and driest deserts. Conditioned by its topography and the presence of orographic fog, the National Park Pan de Azúcar in the Atacama Desert is considered to be such a lichen hotspot. Applying multi-gen loci involving phylogenetic analyses combined with intense morphological and chemical characterization, we determined the taxonomic position of five of the most abundant epiphytic lichens of this area. We evaluated Roccellinastrumspongoideum and Heterodermiafollmannii which were both described from the area but also finally showed that the genus Cenozosia is the endemic sister genus to Ramalina, Vermilacinia, Namibialina and Niebla. As a result, we have described the species Heterodermiaadunca, C.cava and C.excorticata as new lichen species. This work provides a comprehensive dataset for common fog lichen genera of the Coastal Range of the Atacama Desert that can be used as a baseline for monitoring programs and environmental health assessments.

Chilean biocrusts: an impetus for national park management.

In a world threatened by climate change and biodiversity loss, Chile is one of the leading countries regarding national park management and nature conservation. While there are already protection strategies for plants and animals, it is now the time to include biocrusts, the microbial world at our feet that covers large parts of the soils from the Araucaria forests in the South of Chile to the Atacama Desert in the North.

Rare earths stick to rare cyanobacteria: Future potential for bioremediation and recovery of rare earth elements.

Biosorption of metal ions by phototrophic microorganisms is regarded as a sustainable and alternative method for bioremediation and metal recovery. In this study, 12 cyanobacterial strains, including 7 terrestrial and 5 aquatic cyanobacteria, covering a broad phylogenetic diversity were investigated for their potential application in the enrichment of rare earth elements through biosorption. A screening for the maximum adsorption capacity of cerium, neodymium, terbium, and lanthanum was conducted in which Nostoc sp. 20.02 showed the highest adsorption capacity with 84.2-91.5 mg g-1. Additionally, Synechococcus elongatus UTEX 2973, Calothrix brevissima SAG 34.79, Desmonostoc muscorum 90.03, and Komarekiella sp. 89.12 were promising candidate strains, with maximum adsorption capacities of 69.5-83.4 mg g-1, 68.6-83.5 mg g-1, 44.7-70.6 mg g-1, and 47.2-67.1 mg g-1 respectively. Experiments with cerium on adsorption properties of the five highest metal adsorbing strains displayed fast adsorption kinetics and a strong influence of the pH value on metal uptake, with an optimum at pH 5 to 6. Studies on binding specificity with mixed-metal solutions strongly indicated an ion-exchange mechanism in which Na+, K+, Mg2+, and Ca2+ ions are replaced by other metal cations during the biosorption process. Depending on the cyanobacterial strain, FT-IR analysis indicated the involvement different functional groups like hydroxyl and carboxyl groups during the adsorption process. Overall, the application of cyanobacteria as biosorbent in bioremediation and recovery of rare earth elements is a promising method for the development of an industrial process and has to be further optimized and adjusted regarding metal-containing wastewater and adsorption efficiency by cyanobacterial biomass.

Stripped: contribution of cyanobacterial extracellular polymeric substances to the adsorption of rare earth elements from aqueous solutions.

The transformation of modern industries towards enhanced sustainability is facilitated by green technologies that rely extensively on rare earth elements (REEs) such as cerium (Ce), neodymium (Nd), terbium (Tb), and lanthanum (La). The occurrence of productive mining sites, e.g., is limited, and production is often costly and environmentally harmful. As a consequence of increased utilization, REEs enter our ecosystem as industrial process water or wastewater and become highly diluted. Once diluted, they can hardly be recovered by conventional techniques, but using cyanobacterial biomass in a biosorption-based process is a promising eco-friendly approach. Cyanobacteria can produce extracellular polymeric substances (EPS) that show high affinity to metal cations. However, the adsorption of REEs by EPS has not been part of extensive research. Thus, we evaluated the role of EPS in the biosorption of Ce, Nd, Tb, and La for three terrestrial, heterocystous cyanobacterial strains. We cultivated them under N-limited and non-limited conditions and extracted their EPS for compositional analyses. Subsequently, we investigated the metal uptake of a) the extracted EPS, b) the biomass extracted from EPS, and c) the intact biomass with EPS by comparing the amount of sorbed REEs. Maximum adsorption capacities for the tested REEs of extracted EPS were 123.9-138.2 mg g-1 for Komarekiella sp. 89.12, 133.1-137.4 mg g-1 for Desmonostoc muscorum 90.03, and 103.5-129.3 mg g-1 for Nostoc sp. 20.02. A comparison of extracted biomass with intact biomass showed that 16% (Komarekiella sp. 89.12), 28% (Desmonostoc muscorum 90.03), and 41% (Nostoc sp. 20.02) of REE adsorption was due to the biosorption of the extracellular EPS. The glucose- rich EPS (15%-43% relative concentration) of all three strains grown under nitrogen-limited conditions showed significantly higher biosorption rates for all REEs. We also found a significantly higher maximum adsorption capacity of all REEs for the extracted EPS compared to cells without EPS and untreated biomass, highlighting the important role of the EPS as a binding site for REEs in the biosorption process. EPS from cyanobacteria could thus be used as efficient biosorbents in future applications for REE recycling, e.g., industrial process water and wastewater streams.

Common loss of far-red light photoacclimation in cyanobacteria from hot and cold deserts: a case study in the Chroococcidiopsidales.

Deserts represent an extreme challenge for photosynthetic life. Despite their aridity, they are often inhabited by diverse microscopic communities of cyanobacteria. These organisms are commonly found in lithic habitats, where they are partially sheltered from extremes of temperature and UV radiation. However, living under the rock surface imposes additional constraints, such as limited light availability, and enrichment of longer wavelengths than are typically usable for oxygenic photosynthesis. Some cyanobacteria from the genus Chroococcidiopsis can use this light to photosynthesize, in a process known as far-red light photoacclimation, or FaRLiP. This genus has commonly been reported from both hot and cold deserts. However, not all Chroococcidiopsis strains carry FaRLiP genes, thus motivating our study into the interplay between FaRLiP and extreme lithic environments. The abundance of sequence data and strains provided the necessary material for an in-depth phylogenetic study, involving spectroscopy, microscopy, and determination of pigment composition, as well as gene and genome analyses. Pigment analyses revealed the presence of red-shifted chlorophylls d and f in all FaRLiP strains tested. In addition, eight genus-level taxa were defined within the encompassing Chroococcidiopsidales, clarifying the phylogeny of this long-standing polyphyletic order. FaRLiP is near universally present in a generalist genus identified in a wide variety of environments, Chroococcidiopsis sensu stricto, while it is rare or absent in closely related, extremophile taxa, including those preferentially inhabiting deserts. This likely reflects the evolutionary process of gene loss in specialist lineages.

Salty Twins: Salt-Tolerance of Terrestrial Cyanocohniella Strains (Cyanobacteria) and Description of C. rudolphia sp. nov. Point towards a Marine Origin of the Genus and Terrestrial Long Distance Dispersal Patterns.

The ability to adapt to wide ranges of environmental conditions coupled with their long evolution has allowed cyanobacteria to colonize almost every habitat on Earth. Modern taxonomy tries to track not only this diversification process but also to assign individual cyanobacteria to specific niches. It was our aim to work out a potential niche concept for the genus Cyanocohniella in terms of salt tolerance. We used a strain based on the description of C. rudolphia sp. nov. isolated from a potash tailing pile (Germany) and for comparison C. crotaloides that was isolated from sandy beaches (The Netherlands). The taxonomic position of C. rudolphia sp. nov. was evaluated by phylogenetic analysis and morphological descriptions of its life cycle. Salt tolerance of C. rudolphia sp. nov. and C. crotaloides was monitored with cultivation assays in liquid medium and on sand under salt concentrations ranging from 0% to 12% (1500 mM) NaCl. Optimum growth conditions were detected for both strains at 4% (500 mM) NaCl based on morpho-anatomical and physiological criteria such as photosynthetic yield by chlorophyll a fluorescence measurements. Taking into consideration that all known strains of this genus colonize salty habitats supports our assumption that the genus might have a marine origin but also expands colonization to salty terrestrial habitats. This aspect is further discussed, including the ecological and biotechnological relevance of the data presented.

Clinical evaluation and management of a 45-year-old man with confusion, psychosis, agitation, stereotyped behavior, and impaired speech.

Our patient Mr. A is a mentally and physically disabled gentleman. He was first diagnosed with bipolar disorder as a teenager. He incurred a lumbar spinal injury due to a motor vehicle incident in his 20s which led to weakness, numbness, and frequent infection over both of his lower extremities. He also developed alcohol addiction over the course of his life. Mr. A presented to our facility with complicated neuropsychiatric symptoms. By adopting various clinical strategies, we were able to control his symptoms of agitation, self-harm, mood swings, and stereotyped behavior. However, we were not able to improve his neurocognitive functioning or speech impairment which seemed to become severe and irreversible in a period of a few months. We felt disappointed and perplexed by the mixed treatment responses. To understand Mr. A's clinical presentation, various laboratory tests and imaging studies were performed. Different psychotropic medications were used to manage his symptoms. Gradually, we felt that we were able to understand this case better clinically and etiologically. His bipolar disorder, alcohol addiction, and physical injury had likely all contributed to his neuropsychiatric symptoms, directly or indirectly. It is highly possible that an alcohol-related progressive dementia along with his chronic bipolar disorder played a key role in the progression of his brain neurodegeneration. Also, Wernicke-Korsakoff syndrome could reasonably be considered having developed during his clinical course. Moreover, the fluctuation of the patient's neuropsychiatric symptoms we observed during his hospitalization reflects the increased vulnerability of the human brain under sustained neurodegeneration.

Motor callosal disconnection in early relapsing-remitting multiple sclerosis.

In relapsing-remitting multiple sclerosis (RRMS) the corpus callosum (CC) is often and early affected by macroscopic lesions when investigated by conventional MRI. We sought to determine to which extent microstructural and effective disconnection of the CC are already present in RRMS patients at the earliest stages of the disease prior to evidence of macroscopic CC lesion. We compared 16 very early RRMS patients (median expanded disability status scale (EDSS), 1.5; range, 0-2.0) to an age-matched group of healthy controls and focused analysis to the motor CC, i.e. that part of the CC relaying interhemispheric motor information. A combined functional magnetic resonance imaging/diffusion tensor imaging fiber-tracking procedure was applied to identify the callosal motor fibers (CMFs) connecting the hand areas of the primary motor cortices of the two hemispheres. Fractional anisotropy (FA) within the motor CC (FA-CC) assessed the CMF microstructural integrity. Bifocal paired transcranial magnetic stimulation (TMS) tested short-interval interhemispheric inhibition (S-IHI), an established measure of CMF effective connectivity. FA-CC and S-IHI were significantly reduced in early RRMS compared to healthy controls. Furthermore, a significant linear correlation between microstructure (FA-CC) and function (S-IHI) in the controls was broken down in the patients. These abnormalities were obtained in the absence of macroscopic CMF lesion in conventional MRI, and whilst motor hand/arm function in the nine-hole-peg test and corticospinal conduction time were normal. Findings suggest that reductions in FA and S-IHI may serve as surrogate markers of motor callosal disconnection at the earliest stages of RRMS prior to development of macroscopic lesion.

Symphyonema bifilamentata sp. nov., the Right Fischerella ambigua 108b: Half a Decade of Research on Taxonomy and Bioactive Compounds in New Light.

Since 1965 a cyanobacterial strain termed 'Fischerella ambigua 108b' was the object of several studies investigating its potential as a resource for new bioactive compounds in several European institutes. Over decades these investigations uncovered several unique small molecules and their respective biosynthetic pathways, including the polychlorinated triphenyls of the ambigol family and the tjipanazoles. However, the true taxonomic character of the producing strain remained concealed until now. Applying a polyphasic approach considering the phylogenetic position based on the 16S rRNA and the protein coding gene rbcLX, secondary structures and morphological features, we present the strain 'Fischerella ambigua 108b' as Symphyonema bifilamentata sp. nov. 97.28. Although there is the type species (holotype) S. sinense C.-C. Jao 1944 there is no authentic living strain or material for genetic analyses for the genus Symphyonema available. Thus we suggest and provide an epitypification of S. bifilamentata sp. nov. 97.28 as a valid reference for the genus Symphyonema. Its affiliation to the family Symphyonemataceae sheds not only new light on this rare taxon but also on the classes of bioactive metabolites of these heterocytous and true-branching cyanobacteria which we report here. We show conclusively that the literature on the isolation of bioactive products from this organism provides further support for a clear distinction between the secondary metabolism of Symphyonema bifilamentata sp. nov. 97.28 compared to related and other taxa, pointing to the assignment of this organism into a separate genus.