Polymorphic parasitic larvae cooperate to build swimming colonies luring hosts.

Parasites have evolved a variety of astonishing strategies to survive within their hosts, yet the most challenging event in their personal chronicles is the passage from one host to another. It becomes even more complex when a parasite needs to pass through the external environment. Therefore, the free-living stages of parasites present a wide range of adaptations for transmission. Parasitic flatworms from the group Digenea (flukes) have free-living larvae, cercariae, which are remarkably diverse in structure and behavior.1,2 One of the cercariae transmission strategies is to attain a prey-like appearance for the host.3 This can be done through the formation of a swimming aggregate of several cercariae adjoined together by their tails.4 Through the use of live observations and light, electron, and confocal microscopy, we described such a supposedly prey-mimetic colony comprising cercariae of two distinct morphotypes. They are functionally specialized: larger morphotype (sailors) enable motility, and smaller morphotype (passengers) presumably facilitate infection. The analysis of local read alignments between the two samples reveals that both cercaria types have identical 18S, 28S, and 5.8S rRNA genes. Further phylogenetic analysis of these ribosomal sequences indicates that our specimen belongs to the digenean family Acanthocolpidae, likely genus Pleorchis. This discovery provides a unique example and a novel insight into how morphologically and functionally heterogeneous individuals of the same species cooperate to build colonial organisms for the purpose of infection. This strategy bears resemblance to the cooperating castes of the same species found among insects.5.

Comparative effect of conductive and dielectric materials on methanogenesis from highly concentrated volatile fatty acids.

Various conductive materials and their dielectric counterparts were used to get deeper insights into contribution of direct interspecies electron transfer (DIET) in improving methanogenesis from highly concentrated volatile fatty acids (12.5 g/L). Potential CH4 yield, maximum CH4 production rate and lag phase were significantly (up to 1.4, 3.9 and 2.0 times, respectively) improved with addition of stainless-steel mesh (SM) and carbon felt (CF) compared to both control and dielectric counterparts (p < 0.05). kapp increased by 82% for SM and 63% for CF compared to control (p < 0.05). Short thick pili-like structures up to 150 nm in width were formed only in CF and SM biofilms, however, were more abundant for SM. Ureibacillus and Limnochordia specific for SM biofilms, and Coprothermobacter and Ca. Caldatribacterium for CF biofilms, were considered electrogenic. Promotion of DIET by conductive materials is governed by many factors, including specificity of electrogenic groups to material surface.

Effects of various materials used to promote the direct interspecies electron transfer on anaerobic digestion of low-concentration swine manure.

The activation of direct interspecies electron transfer (DIET) by the supplementation of conductive materials is one of the effective and available methods to enhance anaerobic digestion (AD). Microorganisms that colonize the surface of these materials form biofilms, the study of which could provide new insights into the character of the DIET process and its effect on AD. The present study focused on AD performance, microbial community, as well as morphological and topological features of biofilms on various materials used to promote DIET during AD of low-concentration swine manure. The best AD characteristics were observed in stainless steel mesh (SM)/digested cow manure (CM) and polyester felt (PF)/digested sewage sludge (SS) combinations used as material/inoculum, respectively. Thus, potential methane yields in CM-SM and SS-PF were up to 26.4% and 26.2% higher compared to the corresponding controls. Microbial analysis of biofilms revealed the dominance of putatively syntrophic bacteria of the MBA03 group of the Limnochordia class in CM inoculated reactors, and syntrophic proteolytic bacteria of the genus Coprothermobacter and acetogenic Clostridium sensu stricto 1, known for their ability to carry out DIET, in SS inoculated reactors. Biofilms on non-conductive materials contained pili-like structures, which were observed only in SS inoculated reactors. Polyester felt tended to biofoul better than carbon felt, resulting in up to 2.8, 3.2 and 1.8 higher nucleic acid, extracellular polymeric substances, and total biomass content, respectively, depending on the inoculum. These results provide new insights into the different types of DIET that can occur in low-loaded AD systems with attached growth.

Serotonin limits generation of chromaffin cells during adrenal organ development.

Adrenal glands are the major organs releasing catecholamines and regulating our stress response. The mechanisms balancing generation of adrenergic chromaffin cells and protecting against neuroblastoma tumors are still enigmatic. Here we revealed that serotonin (5HT) controls the numbers of chromaffin cells by acting upon their immediate progenitor "bridge" cells via 5-hydroxytryptamine receptor 3A (HTR3A), and the aggressive HTR3Ahigh human neuroblastoma cell lines reduce proliferation in response to HTR3A-specific agonists. In embryos (in vivo), the physiological increase of 5HT caused a prolongation of the cell cycle in "bridge" progenitors leading to a smaller chromaffin population and changing the balance of hormones and behavioral patterns in adulthood. These behavioral effects and smaller adrenals were mirrored in the progeny of pregnant female mice subjected to experimental stress, suggesting a maternal-fetal link that controls developmental adaptations. Finally, these results corresponded to a size-distribution of adrenals found in wild rodents with different coping strategies.

Energy Metabolism and Intracellular pH Alteration in Neural Spheroids Carrying Down Syndrome.

Brain diseases including Down syndrome (DS/TS21) are known to be characterized by changes in cellular metabolism. To adequately assess such metabolic changes during pathological processes and to test drugs, methods are needed that allow monitoring of these changes in real time with minimally invasive effects. Thus, the aim of our work was to study the metabolic status and intracellular pH of spheroids carrying DS using fluorescence microscopy and FLIM. For metabolic analysis we measured the fluorescence intensities, fluorescence lifetimes and the contributions of the free and bound forms of NAD(P)H. For intracellular pH assay we measured the fluorescence intensities of SypHer-2 and BCECF. Data were processed with SPCImage and Fiji-ImageJ. We demonstrated the predominance of glycolysis in TS21 spheroids compared with normal karyotype (NK) spheroids. Assessment of the intracellular pH indicated a more alkaline intracellular pH in the TS21 spheroids compared to NK spheroids. Using fluorescence imaging, we performed a comprehensive comparative analysis of the metabolism and intracellular pH of TS21 spheroids and showed that fluorescence microscopy and FLIM make it possible to study living cells in 3D models in real time with minimally invasive effects.