Biofilm formation initiating rotifer-specific biopolymer and its predicted components.

The rotifer-specific biopolymer, namely Rotimer, is a recently discovered group of the biomolecule family. Rotimer has an active role in the biofilm formation initiated by rotifers (e.g., Euchlanis dilatata or Adineta vaga) or in the female-male sexual interaction of monogononts. To understand the Ca2+- and polarity-dependent formation of this multifunctional viscoelastic material, it is essential to explore its molecular composition. The investigation of the rotifer-enhanced biofilm and Rotimer-inductor conglomerate (RIC) formation yielded several protein candidates to predict the Rotimer-specific main components. The exudate of E. dilatata males was primarily applied from different biopolimer-containing samples (biofilm or RIC). The advantage of males over females lies in their degenerated digestive system and simple anatomy. Thus, their exudate is less contaminated with food and endosymbiont elements. The sequenced and annotated genome and transcriptome of this species opened the way for identifying Rotimer proteins by mass spectrometry. The predicted rotifer-biopolymer forming components are SCO-spondins and 14-3-3 protein. The characteristics of Rotimer are similar to Reissner's fiber, which is found in the central nervous system of vertebrates and is mainly formed from SCO-spondins. This molecular information serves as a starting point for its interdisciplinary investigation and application in biotechnology, biomedicine, or neurodegeneration-related drug development.

Particle-dependent reproduction and exogenic biopolymer secretion of protozoa co-cultured rotifers.

The rotifer-specific exogenic biopolymer, named Rotimer and its related molecular processes are affected by physical and chemical factors (e.g., temperature, pH or metal ions); however, the study of biological influences (e.g., the presence protozoa) concerning the particle-dependent reproduction (egg laying) and 'biopolymer producing capacity' (BPC) of rotifers is the objective of the present work. Non-planktonic rotifer species (Philodina acuticornis, Adineta vaga, Euchlanis dilatata, and Lecane bulla) were studied in paired micrometazoa-protozoa co-cultures involving Paramecium, Diplonema, and Amoeba. These protozoa can be beneficial food sources, enhancing reproduction, or even toxic factors for the above-mentioned animals, but can also function as particle-like mechanical stimulators. Furthermore, current studies reveal that bdelloids, similarly to monogonants, produce filamentous exudate; moreover, the body of bdelloids is covered by their exudate, unlike that of monogonants, especially in the case of A. vaga. A mathematical formula was developed as an improved version of a previously published viability marker to characterize the BPC and the relative amount of produced exudate in different conditions. Rotifer species secreting biopolymers appear to be a general trait indicating a common evolutionary background (e.g., calcium- and particle dependency) of such molecules; therefore, the BPC becomes an experiential sublethal influencing marker to these micrometazoans.

The interacting rotifer-biopolymers are anti- and disaggregating agents for human-type beta-amyloid in vitro.

Neurodegeneration-related human-type beta-amyloid 1-42 aggregates (H-Aß) are one of the biochemical markers and executive molecules in Alzheimer's disease. The exogenic rotifer-specific biopolymer, namely Rotimer, has a protective effect against H-Aß toxicity on Euchlanis dilatata and Lecane bulla monogonant rotifers. Due to the external particle-dependent secreting activity of these animals, this natural exudate exists in a bound form on the surface of epoxy-metal beads, named as Rotimer Inductor Conglomerate (RIC). In this current work the experiential in vitro molecular interactions between Rotimer and Aßs are presented. The RIC form was uniformly used against H-Aß aggregation processes in stagogram- and fluorescent-based experiments. These well-known cell-toxic aggregates stably and quickly (only taking a few minutes) bind to RIC. The epoxy beads (as carriers) alone or the scrambled version of H-Aß (with random amino acid sequence) were the ineffective and inactive negative controls of this experimental system. The RIC has significant interacting, anti-aggregating and disaggregating effects on H-Aß. To detect these experiments, Bis-ANS and Thioflavin T were applied during amyloid binding, two aggregation-specific functional fluorescent dyes with different molecular characteristics. This newly described empirical interaction of Rotimer with H-Aß is a potential starting point and source of innovation concerning targeted human- and pharmaceutical applications.

External modulation of Rotimer exudate secretion in monogonant rotifers.

The Rotimer, a rotifer-specific biopolymer, is an exogenic bioactive exudate secreted by different monogonant species (e.g. Euchlanis dilatata or Lecane bulla). The production of this viscoelastic biomolecule is induced by different micro-particles, thereby forming a special Rotimer-Inductor Conglomerate (RIC) in a web format. In this case, the water insoluble Carmine crystals, filtered to size (max. diameter was 50 µm), functioned as an inductor. The RIC production is an adequate empirical indicator to follow up this filamentous biopolymer secretion experientially; moreover, this procedure is very sensitive to the environmental factors (temperature, pH, metals and possible natural pollutant agents). The above mentioned species show completely different reactions to these factors, except to the presence of calcium and to the modulating effects of different drugs. One of the novelties of this work is that the Rotimer secretion and consequently, the RIC-formation is a mutually obligatory and evolutionary calcium-dependent process in the concerned monogonants. This in vivo procedure needs calcium, both for the physiology of animals and for fiber formation, particularly in the latter case. The conglomerate covered area (%) and the detection of the longest filament (mm) of the given RIC were the generally and simultaneously applied methods in the current modulating experiments. Exploring the regulatory (e.g. calcium-dependency) and stimulating (e.g. Lucidril effect) possibilities of biopolymer secretion are the basis for optimizing the RIC-production capacities of these micro-metazoans.

Exogenic production of bioactive filamentous biopolymer by monogonant rotifers.

The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species. Induction of Rotimer secretion can only be achieved by mechanically irritating rotifer ciliate with administering different types (yeast cell skeleton, denatured BSA, epoxy, Carmine or urea crystals and micro-cellulose) and sizes (approx. from 2.5 to 50 µm diameter) of inert particles, as inductors or visualization by adhering particles. The thickness of this Rotimer is 33 ± 3 nm, detected by scanning electron microscope. This material has two structural formations (fiber or gluelike) in nano dimension. The existence of the novel adherent natural product becomes visible by forming a 'Rotimer-Inductor Conglomerate' (RIC) web structure within a few minutes. The RIC-producing capacity of animals, depends on viability, is significantly modified according to physiological- (depletion), drug- (toxin or stimulator) and environmental (temperature, salt content and pH) effects. The E. dilatata-produced RIC is affected by protein disruptors but is resistant to several chemical influences and its Rotimer component has an overwhelming cell (algae, yeast and human neuroblastoma) motility inhibitory effect, associated with low toxicity. This biopolymer-secretion-capacity is protective of rotifers against human-type beta-amyloid aggregates.

Neurodegeneration-related beta-amyloid as autocatabolism-attenuator in a micro-in vivo system.

Investigation of human neurodegeneration-related aggregates of beta-amyloid 1-42 (Aß42) on bdelloid rotifers is a novel interdisciplinary approach in life sciences. We reapplied an organ size-based in vivo monitoring system, exploring the autocatabolism-related alterations evoked by Aß42, in a glucose-supplemented starvation model. The experientially easy-to-follow size reduction of the bilateral reproductive organ (germovitellaria) in fasted rotifers was rescued by Aß42, serving as a nutrient source- and peptide sequence-specific attenuator of the organ shrinkage phase and enhancer of the regenerative one including egg reproduction. Recovery of the germovitellaria was significant in comparison with the greatly shrunken form. In contrast to the well-known neurotoxic Aß42 (except the bdelloids) with specific regulatory roles, the artificially designed scrambled version (random order of amino acids) was inefficient in autocatabolism attenuation, behaving as negative control. This native Aß42-related modulation of the 'functionally reversible organ shrinkage' can be a potential experiential and supramolecular marker of autocatabolism in vivo.

Alzheimer risk factors age and female sex induce cortical Aß aggregation by raising extracellular zinc.

Aging and female sex are the major risk factors for Alzheimer's disease and its associated brain amyloid-ß (Aß) neuropathology, but the mechanisms mediating these risk factors remain uncertain. Evidence indicates that Aß aggregation by Zn2+ released from glutamatergic neurons contributes to amyloid neuropathology, so we tested whether aging and sex adversely influences this neurophysiology. Using acute hippocampal slices, we found that extracellular Zn2+-elevation induced by high K+ stimulation was significantly greater with older (65 weeks vs 10 weeks old) rats, and was exaggerated in females. This was driven by slower reuptake of extracellular Zn2+, which could be recapitulated by mitochondrial intoxication. Zn2+:Aß aggregates were toxic to the slices, but Aß alone was not. Accordingly, high K+ caused synthetic human Aß added to the slices to form soluble oligomers as detected by bis-ANS, attaching to neurons and inducing toxicity, with older slices being more vulnerable. Age-dependent energy failure impairing Zn2+ reuptake, and a higher maximal capacity for Zn2+ release by females, could contribute to age and sex being major risk factors for Alzheimer's disease.

Kynurenic Acid and Its Analogs Are Beneficial Physiologic Attenuators in Bdelloid Rotifers.

The in vivo investigation of kynurenic acid (KYNA) and its analogs is one of the recent exciting topics in pharmacology. In the current study we assessed the biological effects of these molecules on bdelloid rotifers (Philodina acuticornis and Adineta vaga) by monitoring changes in their survival and phenotypical characteristics. In addition to longitudinal (slowly changing) markers (survival, number of rotifers alive and body size index), some dynamic (quickly responding) ones (cellular reduction capacity and mastax contraction frequency) were measured as well. KYNA and its analogs increased longevity, reproduction and growth, whereas reduction capacity and energy-dependent muscular activity decreased conversely. We found that spermidine, a calorie restriction mimetic, exerted similar changes in the applied micro-invertebrates. This characterized systemic profile evoked by the above-mentioned compounds was named beneficial physiologic attenuation. In reference experiments, using a stimulator (cyclic adenosine monophosphate) and a toxin (sodium azide), all parameters changed in the same direction (positively or negatively, respectively), as expected. The currently described adaptive phenomenon in bdelloid rotifers may provide holistic perspectives in translational research.