ABSTRACT
The increasing frequency of cyanobacteria blooms in waterbodies caused by ecosystem eutrophication could endanger human health. This risk can be mitigated by effective monitoring incorporating molecular methods. To date, most molecular studies on toxigenic cyanobacteria have been limited to microcystins (MCs), disregarding other cyanotoxins, to freshwater planktic habitats while ignoring benthic habitats, and to limited geographic areas (usually one or a few specific waterbodies). In this study, we used PCR-based methods including PCR product sequencing and chemical-analytical methods (LC-MS/MS) to screen many plankton (n = 123) and biofilm samples (n = 113) originating from 29 Alpine lakes and 18 rivers for their cyanotoxin production potential. Both mcyE (indicating MC synthesis) and anaC (indicating anatoxin (ATX) synthesis) gene fragments were able to qualitatively predict MC or ATX occurrence. The abundance of mcyE gene fragments was significantly related to MC concentrations in plankton samples (R2 = 0.61). mcyE gene fragments indicative of MC synthesis were most abundant in planktic samples (65 %) and were assigned to the genera Planktothrix and Microcystis. However, mcyE rarely occurred in biofilms of lakes and rivers, i.e., 4 % and 5 %, respectively, and were assigned to Microcystis, Planktothrix, and Nostoc. In contrast, anaC gene fragments occurred frequently in planktic samples (14 % assigned to Tychonema, Phormidium (Microcoleus), and Oscillatoria), but also in biofilms of lakes (49 %) and rivers (18 %) and were assigned to the genera Phormidium, Oscillatoria, and Nostocales. The cyrJ gene fragment indicating cylindrospermopsin synthesis occurred only once in plankton (assigned to Dolichospermum), while saxitoxin synthesis potential was not detected. For plankton samples, monomictic and less eutrophic conditions were positively related to mcyE/MC occurrence frequency, while oligomictic conditions were related to anaC/ATX frequency. The anaC/ATX frequency in biofilm was related to the lake habitats generally showing higher biodiversity as revealed from metabarcoding in a parallel study.
Subject(s)
Cyanobacteria , Lakes , Rivers , Lakes/microbiology , Cyanobacteria/genetics , Rivers/microbiology , Microcystins , Environmental Monitoring , Biofilms , Bacterial Toxins/genetics , EutrophicationABSTRACT
Desert soil hosts many microorganisms, whose activities are essential from an ecological viewpoint. Moreover, they are of great anthropic interest. The knowledge of extreme environments microbiomes may be beneficial for agriculture, technology, and human health. In this study, 11 Arthrobacter strains from topsoil samples collected from the Great Gobi A Strictly Protected Area in the Gobi Desert, were characterized by a combination of different techniques. The phylogenetic analysis, performed using their 16S rDNA sequences and the most similar Arthrobacter sequences found in databases, revealed that most of them were close to A. crystallopoietes, while others joined a sister group to the clade formed by A. humicola, A. pascens, and A. oryzae. The resistance of each strain to different antibiotics, heavy-metals, and NaCl was also tested as well as the inhibitory potential against human pathogens (i.e., Burkholderia ssp., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus ssp.) via cross-streaking, to check the production of metabolites with antimicrobial activity. Data obtained revealed that all strains were resistant to heavy metals and were able to strongly interfere with the growth of many of the human pathogens tested. The volatile organic compounds (VOCs) profile of the 11 Arthrobacter strains was also analyzed. A total of 16 different metabolites were found, some of which were already known for having an inhibitory action against different Gram-positive and Gram-negative bacteria. Isolate MS-3A13, producing the highest quantity of VOCs, is the most efficient against Burkholderia cepacia complex (Bcc), K. pneumoniae, and coagulase-negative Staphylococci (CoNS) strains. This work highlights the importance of understanding microbial populations' phenotypical characteristics and dynamics in extreme environments to uncover the antimicrobial potential of new species and strains.
ABSTRACT
Understanding how microbial communities survive in extreme environmental pressure is critical for interpreting ecological patterns and microbial diversity. Great Gobi A Strictly Protected Area represents an intriguing model for studying the bacterial community since it is a protected and intact wild area of the Mongolian desert. In this work, the composition of a bacterial community of the soil from four oases was characterized by extracting total DNA and sequencing through the Illumina NovaSeq platform. In addition, the soil's chemical and physical properties were determined, and their influence on shaping the microbial communities was evaluated. The results showed a high variability of bacterial composition among oases. Moreover, combining specific chemical and physical parameters significantly shapes the bacterial community among oases. Data obtained suggested that the oases were highly variable in physiochemical parameters and bacterial communities despite the similar extreme climate conditions. Moreover, core functional microbiome were constituted by aerobic chemoheterotrophy and chemoheterotrophy, mainly contributed by the most abundant bacteria, such as Actinobacteriota, Pseudomonadota, and Firmicutes. This result supposes a metabolic flexibility for sustaining life in deserts. Furthermore, as the inhabitants of the extreme regions are likely to produce new chemical compounds, isolation of key taxa is thus encouraged.
ABSTRACT
This study contributes knowledge on the detection of depression through handwriting/drawing features, to identify quantitative and noninvasive indicators of the disorder for implementing algorithms for its automatic detection. For this purpose, an original online approach was adopted to provide a dynamic evaluation of handwriting/drawing performance of healthy participants with no history of any psychiatric disorders ([Formula: see text]), and patients with a clinical diagnosis of depression ([Formula: see text]). Both groups were asked to complete seven tasks requiring either the writing or drawing on a paper while five handwriting/drawing features' categories (i.e. pressure on the paper, time, ductus, space among characters, and pen inclination) were recorded by using a digitalized tablet. The collected records were statistically analyzed. Results showed that, except for pressure, all the considered features, successfully discriminate between depressed and nondepressed subjects. In addition, it was observed that depression affects different writing/drawing functionalities. These findings suggest the adoption of writing/drawing tasks in the clinical practice as tools to support the current depression detection methods. This would have important repercussions on reducing the diagnostic times and treatment formulation.
Subject(s)
Depression , Handwriting , Humans , Depression/diagnosis , AlgorithmsABSTRACT
Seed-associated microbiota are believed to play a crucial role in seed germination, seedling establishment, and plant growth and fitness stimulation, due to the vertical transmission of a core microbiota from seeds to the next generations. It might be hypothesized that medicinal and aromatic plants could use the seeds as vectors to vertically transfer beneficial endophytes, providing plants with metabolic pathways that could influence phytochemicals production. Here, we investigated the localization, the structure and the composition of the bacterial endophytic population that resides in Origanum heracleoticum L. seeds. Endocellular bacteria, surrounded by a wall, were localized close to the aleurone layer when using light and transmission electron microscopy. From surface-sterilized seeds, cultivable endophytes were isolated and characterized through RAPD analysis and 16S RNA gene sequencing, which revealed the existence of a high degree of biodiversity at the strain level and the predominance of the genus Pseudomonas. Most of the isolates grew in the presence of six selected antibiotics and were able to inhibit the growth of clinical and environmental strains that belong to the Burkholderia cepacia complex. The endophytes production of antimicrobial compounds could suggest their involvement in plant secondary metabolites production and might pave the way to endophytes exploitation in the pharmaceutical field.
ABSTRACT
In social interactions, the reciprocity norm implies to adjust one's behavior to that of the other agents. Conversely, behaving according to self-interest involves taking into account the reciprocity principle only if it does not hinder the achievement of one's goals. However, reciprocity and self-interest may conflict with each other, as when returning a kind action involves sacrificing the possibility to achieve a personal objective. The conflict could be exacerbated by some contextual factors, such as competitive pressures. This study investigated, in a competitive interaction context, which principle prevails when the two conflict. To this end, 276 unpaid participants (M = 138) took part in a two-stage experiment entailing a simulated interaction with a fictitious opponent, which behaved selfishly, fairly or altruistically toward them during the first stage. Participants had to decide whether or not to reciprocate the opponent's previous behavior, which in the critical experimental conditions conflicted with the goal to successfully complete the experiment. So, they were faced with a moral dilemma. Competition degree was manipulated to make the conflict between reciprocity and self-interest more or less harsh. Moreover, we tested whether the putative effect of experimental manipulation was mediated by changes in context-related affective states and personal beliefs about morality. Results showed that decision-making was principally influenced by reciprocity. Regardless of the competition degree, participants preferred to engage in reciprocal behavior even when this compromised their personal interest. Affective states and beliefs changed in response to the experimental manipulation, but they did not mediate the effect of the independent variable on decision-making.
ABSTRACT
The taxonomic identification of organisms based on the amplification of specific genetic markers (metabarcoding) implicitly requires adequate discriminatory information and taxonomic coverage of environmental DNA sequences in taxonomic databases. These requirements were quantitatively examined by comparing the determination of cyanobacteria and microalgae obtained by metabarcoding and light microscopy. We used planktic and biofilm samples collected in 37 lakes and 22 rivers across the Alpine region. We focused on two of the most used and best represented genetic markers in the reference databases, namely the 16S rRNA and 18S rRNA genes. A sequence gap analysis using blastn showed that, in the identity range of 99-100%, approximately 30% (plankton) and 60% (biofilm) of the sequences did not find any close counterpart in the reference databases (NCBI GenBank). Similarly, a taxonomic gap analysis showed that approximately 50% of the cyanobacterial and eukaryotic microalgal species identified by light microscopy were not represented in the reference databases. In both cases, the magnitude of the gaps differed between the major taxonomic groups. Even considering the species determined under the microscope and represented in the reference databases, 22% and 26% were still not included in the results obtained by the blastn at percentage levels of identity ≥95% and ≥97%, respectively. The main causes were the absence of matching sequences due to amplification and/or sequencing failure and potential misidentification in the microscopy step. Our results quantitatively demonstrated that in metabarcoding the main obstacles in the classification of 16S rRNA and 18S rRNA sequences and interpretation of high-throughput sequencing biomonitoring data were due to the existence of important gaps in the taxonomic completeness of the reference databases and the short length of reads. The study focused on the Alpine region, but the extent of the gaps could be much greater in other less investigated geographic areas.
Subject(s)
Cyanobacteria , Microalgae , Base Sequence , Cyanobacteria/genetics , Eukaryota , European Alpine Region , Genetic Markers , Microalgae/genetics , Phylogeny , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 18SABSTRACT
Strigiformes are affected by a substantial decline mainly caused by habitat loss and destruction, poaching, and trapping. Moreover, the increasing trend in bird trade and the growing interest in wild-caught rather than captive-bred birds are expected to encourage illegal trade. The biomolecular investigation represents a valuable tool to track illegal trade and to explore the genetic variability to preserving biodiversity. Microsatellite loci (STRs) are the most used markers to study genetic variability. Despite the availability of species-specific microsatellite loci in Strigiformes, a unique panel permitting the description of the genetic variability across species has not been identified yet. We tested 32 highly polymorphic microsatellite markers to evaluate the reliability of a unique microsatellite panel in different species of Strigiformes and its use for conservation and forensic purposes. We included in the study 84 individuals belonging to 28 parental groups and 11 species of Strigiformes. After screening polymorphic microsatellite loci, the description of genetic variability, and the kinship assessment, we characterized a final panel of 12 microsatellite loci able to identify individuals in 9 Strigiformes species. This STR panel might support the authorities in the forensic investigation for suspected smugglers and false parental claims; moreover, it can be useful to evaluate relatedness among individuals in captive-bred populations and to implement research projects finalized to the description of the genetic variability in wild populations.
Subject(s)
Forensic Genetics/methods , Microsatellite Repeats , Strigiformes/classification , Animals , Animals, Wild/classification , Animals, Wild/genetics , Biodiversity , Conservation of Natural Resources , Species Specificity , Strigiformes/geneticsABSTRACT
In 2014, high-throughput sequencing of libraries of total DNA from olive trees allowed the identification of two geminivirus-like contigs. After conventional resequencing of the two genomic DNAs, their analysis revealed they belonged to the same viral entity, for which the provisional name of Olea europaea geminivirus (OEGV) was proposed. Although DNA-A showed a genome organization similar to that of New World begomoviruses, DNA-B had a peculiar ORF arrangement, consisting of a movement protein (MP) in the virion sense and a protein with unknown function on the complementary sense. Phylogenetic analysis performed either on full-length genome or on coat protein, replication associated protein (Rep), and MP sequences did not endorse the inclusion of this virus in any of the established genera in the family Geminiviridae. A survey of 55 plants revealed that the virus is widespread in Apulia (Italy) with 91% of the samples testing positive, although no correlation of OEGV with a disease or specific symptoms was encountered. Southern blot assay suggested that the virus is not integrated in the olive genome. The study of OEGV-derived siRNA obtained from small RNA libraries of leaves and fruits of three different cultivars, showed that the accumulation of the two genomic components is influenced by the plant genotype while virus-derived-siRNA profile is in line with other geminivirids reported in literature. Single-nucleotide polymorphism (SNP) analysis unveiled a low intra-specific variability.
Subject(s)
Geminiviridae/classification , Geminiviridae/pathogenicity , Genome, Viral , Olea/genetics , Olea/virology , Phylogeny , DNA Viruses/genetics , Geminiviridae/genetics , Geminiviridae/isolation & purification , High-Throughput Nucleotide Sequencing , Italy , Plants/virology , Virion/genetics , Virion/isolation & purificationABSTRACT
This study aimed to characterise the gut microbiome composition of European hares (Lepus europaeus) and its potential changes after a short-term diet modification. The high sensitivity of European hare to habitat changes makes this species a good model to analyse possible alterations in gut microbiome after the introduction of additional nourishment into the diet. In total, 20 pairs were chosen for the experiments; 10 pairs formed the control group and were fed with standard fodder. The other 10 pairs represented the experimental group, whose diet was integrated with apples and carrots. The DNA from fresh faecal pellets collected after 4 days from the start of the experiment was extracted and the V3-V4 hypervariable regions were amplified and sequenced using the Illumina MiSeq® platform. The obtained amplicon sequence variants were classified into 735 bacterial genera belonging to 285 families and 36 phyla. The control and the experimental groups appeared to have a homogenous dispersion for the two taxonomic levels analysed with the most abundant phyla represented by Bacteroidetes and Firmicutes. No difference between control and experimental samples was detected, suggesting that the short-term variation in food availability did not alter the hares' gut microbiome. Further research is needed to estimate significant time threshold.
ABSTRACT
Objectives: The mainstream position on regret in psychological literature is that its necessary conditions are agency and responsibility, that is, to choose freely but badly. Without free choice, other emotions, such as disappointment, are deemed to be elicited when the outcome is worse than expected. In two experiments, we tested the opposite hypothesis that being forced by external circumstances to choose an option inconsistent with one's own intentions is an important source of regret and a core component of its phenomenology, regardless of the positivity/negativity of the post-decision outcome. Along with regret, four post-decision emotions - anger toward oneself, disappointment, anger toward circumstances, and satisfaction - were investigated to examine their analogies and differences to regret with regard to antecedents, appraisals, and phenomenological aspects. Methods: Through the scenario methodology, we manipulated three variables: choice (free/forced), outcome (positive/negative), and time (short/long time after decision-making). Moreover, we investigated whether responsibility, decision justifiability, and some phenomenological aspects (self-attribution, other attribution, and contentment) mediated the effect exerted by choice, singularly or in interaction with outcome and time, on the five emotions. Each study was conducted with 336 participants, aged 18-60. Results: The results of both studies were similar and supported our hypothesis. In particular, regret elicited by forced choice was always high, regardless of the valence of outcome, whereas free choice elicited regret was high only with a negative outcome. Moreover, regret was unaffected by responsibility and decision justifiability, whereas it was affected by the three phenomenological dimensions. Conclusion: Our results suggest that (1) the prevailing theory of regret is too binding, since it posits as necessary some requirements which are not; (2) the antecedents and phenomenology of regret are broader than it is generally believed; (3) decision-making produces a complex emotional constellation, where the different emotions, singularly and/or in combination, constitute the affective responses to the different aspects of decision-making.
ABSTRACT
The ultimatum (UG) and dictator (DG) games are two tasks where a sum of money has to be divided between two players: a proposer and a receiver. Following the rational choice theory, proposers should offer the minimum in the UG and nothing in the DG, due to the presence/absence of the receivers' bargaining power. The fact that people generally make non-negligible offers in both games has suggested divergent explicative hypotheses and has generated extensive research to examine exogenous and endogenous factors underlying such decisions. Among the contextual factors affecting the proposers' offers, the sense of entitlement or of ownership has been shown to reduce offers significantly. A frequent way to induce the sense of entitlement/ownership has been to assign the role of proposer to the player who apparently has better scored in skill tasks executed before the UG or DG or has more contributed, through a previous luck game, to the amount to be shared. Such manipulations, however, could produce a possible overlapping between "ownership" and "merit," that in this study we aimed to disentangle. We manipulated the participants' initial endowment through a luck game, by increasing, decreasing or leaving it unchanged, to investigate whether winnings or losses by chance influenced offers in UG and DG in similar or different ways depending on their respective features. All participants played as proposers but this role was apparently random and disconnected from the outcomes of the luck game. Furthermore, we investigated whether the putative effect of experimental manipulation was mediated by the changes in emotions elicited by the luck game and/or by the emotions and beliefs related to decision-making. We used a non-economic version of the games, in which tokens were divided instead of money. In the study, 300 unpaid undergraduates (M = 152) from different degree programs, aged between 18 and 42 years, participated. The results revealed that the effect of outcome manipulation on offers was moderated by the specific structure of the UG and DG. Instead, emotional reactions barely mediated the effect of the experimental manipulation, suggesting that their role in those decisions is less relevant than is assumed in the literature.
ABSTRACT
BACKGROUND AND AIMS: Although numerous correlational studies have shown an association between cognitive distortions and problem gambling, only a few behavioral studies have investigated this topic by comparing problem (PGs) and non-problem gamblers (N-PGs). This quasi-experiment investigated the occurrence in both groups of a widespread cognitive distortion, the gambler's fallacy (GF), using a fictitious roulette game. Moreover, it investigated whether the GF increased the bet amount and whether impulsivity and sensation seeking were associated with the GF. METHODS: Two indices of the GF were used: a cognitive index, the probability estimate of each outcome (black/red) after manipulating the final run length (the same outcome occurring four times/once), and a behavioral index, the choice of the outcome on which to bet. A total of 320 (160 PGs and 160 N-PGs) unpaid male volunteers, aged between 18 and 68, participated in this study. HYPOTHESES: Erroneous probability estimates should mediate the effect of longer runs on the alternation choice (i.e., the choice of an outcome different from the previous one) to support the occurrence of GF. The GF should increase betting. PGs should be more prone than N-PGs to GF. RESULTS: The choice of the outcome depended on both cognitive (erroneous probability estimates) and affective (preference for red) factors. PGs bet more than N-PGs but they were not more prone than N-PGs to incurring GF. Although impulsivity and sensation seeking were more intense in PGs than in N-PGs, they scarcely affected GF. DISCUSSION AND CONCLUSIONS: Overall, our results corroborate the tested model of the GF that links mistaken probability estimates, choice of the outcome on which to bet, and bet amount. However, they are similar to PGs and N-PGs and fail to corroborate the hypothesis that the GF is more evident in PGs.
Subject(s)
Decision Making/physiology , Gambling/physiopathology , Impulsive Behavior/physiology , Personality/physiology , Thinking/physiology , Adolescent , Adult , Aged , Humans , Male , Middle Aged , Young AdultABSTRACT
A new gemycircularvirus sequence was obtained from total DNAs extracted from olive leaves and twigs tissues. Its complete genome consists of a single-stranded circular DNA of 2,145 nt, whose sequence was obtained by rolling circle amplification (RCA). Genome analysis identified three open reading frames, sharing homologies with the coat and replication-associated proteins, these latter in the anti-parallel strand, of known gemycircularvirus species. Search for homologies showed that the circular ssDNA sequence is distantly related to other gemycircularviruses thus originating from a new virus species, for which the name olive-associated gemycircularvirus 1 (OaGV1) is proposed. A survey in two different olive-growing areas of the Apulian region (Southern Italy), showed a limited distribution of OaGV1.
Subject(s)
DNA Viruses/classification , DNA Viruses/isolation & purification , Olea/virology , Plant Viruses/classification , Plant Viruses/isolation & purification , DNA Viruses/genetics , DNA, Viral/chemistry , DNA, Viral/genetics , Italy , Open Reading Frames , Phylogeny , Plant Viruses/genetics , Sequence Analysis, DNA , Sequence HomologyABSTRACT
Hybridisation between a domesticated species and its wild ancestor is an important conservation problem, especially if it results in the introgression of domestic gene variants into wild species. Nevertheless, the legal status of hybrids remains unregulated, partially because of the limited understanding of the hybridisation process and its consequences. The occurrence of hybridisation between grey wolves and domestic dogs is well documented from different parts of the wolf geographic range, but little is known about the frequency of hybridisation events, their causes and the genetic impact on wolf populations. We analysed 61K SNPs spanning the canid genome in wolves from across Eurasia and North America and compared that data to similar data from dogs to identify signatures of admixture. The haplotype block analysis, which included 38 autosomes and the X chromosome, indicated the presence of individuals of mixed wolf-dog ancestry in most Eurasian wolf populations, but less admixture was present in North American populations. We found evidence for male-biased introgression of dog alleles into wolf populations, but also identified a first-generation hybrid resulting from mating between a female dog and a male wolf. We found small blocks of dog ancestry in the genomes of 62% Eurasian wolves studied and melanistic individuals with no signs of recent admixed ancestry, but with a dog-derived allele at a locus linked to melanism. Consequently, these results suggest that hybridisation has been occurring in different parts of Eurasia on multiple timescales and is not solely a recent phenomenon. Nevertheless, wolf populations have maintained genetic differentiation from dogs, suggesting that hybridisation at a low frequency does not diminish distinctiveness of the wolf gene pool. However, increased hybridisation frequency may be detrimental for wolf populations, stressing the need for genetic monitoring to assess the frequency and distribution of individuals resulting from recent admixture.
ABSTRACT
Lack of the fragile X mental retardation protein leads to Fragile X syndrome (FXS) while increased levels of FMR1 mRNA, as those observed in premutation carriers can lead to Fragile X- associated tremor ataxia syndrome (FXTAS). Until recently, FXTAS had been observed only in carriers of an FMR1 premutation (55-200 CGG repeats); however the disorder has now been described in individuals carriers of an intermediate allele (45-54 CGG repeats) as well as in a subject with a full mutation with mosaicism.Here, we report on molecular and clinical data of a male FMR1 mosaic individual with full and premutation alleles. Molecular analysis of FMR1 and FMRP expression in this subject is consistent with a FXS phenotype. We observed reduced expression of FMRP in both peripheral blood and brain leading to the FXS diagnosis. In addition, a dramatic 90% depletion of both FMR1 mRNA and FMRP levels was observed in the blood, as normally observed in FXS cases, and an even greater depletion in the brain. A clinical report of this patient, at age 71, described neurodegenerative signs of parkinsonism that were likely, in retrospect, part of a FXTAS scenario as post-mortem examination shows the presence of intranuclear inclusions, the hallmark pathology of FXTAS.The findings presented in this study indicate co-morbidity for both FXS and FXTAS in this individual carrying both full and premutation FMR1 alleles. In addition, based on symptoms and pathological and molecular evidence, this report suggests the need to redefine the diagnostic criteria of FXTAS.
ABSTRACT
The fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder caused by CGG trinucleotide repeat expansions in the fragile X mental retardation 1 (FMR1) gene. The neuropathological hallmark of FXTAS is the presence of ubiquitin-positive intranuclear inclusions in neurons and in astroglia. Intranuclear inclusions have also been reported in the neurons of male CGG KI mice carrying an expanded CGG trinucleotide repeat and used to model FXTAS, but no study has been carried out quantifying inclusions in female CGG KI mice heterozygous for the fragile X premutation. We used histologic and immunocytochemical methods to determine the pathological features of intranuclear inclusions in astroglia and neurons. In female CGG KI mice, ubiquitin-positive intranuclear inclusions were found in neurons and astroglia throughout the brain in cortical and subcortical regions. These inclusions increased in number and became larger with advanced age and increasing CGG repeat length, supporting hypotheses that these pathologic features are progressive across the lifespan. The number of inclusions in neurons was reduced by â¼25% in female CGG KI mice compared to male CGG KI mice, but not so low as the 50% predicted. These data emphasize the need to evaluate the neurocognitive and pathological features in female carriers of the fragile X premutation with and without FXTAS symptomatology is warranted, as this population shows similar neuropathological features present in male FXTAS patients.
Subject(s)
Astrocytes/pathology , Brain/pathology , Fragile X Syndrome/pathology , Intranuclear Inclusion Bodies/pathology , Neurons/pathology , Aged , Animals , Disease Models, Animal , Female , Fluorescent Antibody Technique , Fragile X Syndrome/genetics , Heterozygote , Humans , Immunohistochemistry , Mice , Microscopy, Confocal , Reverse Transcriptase Polymerase Chain Reaction , Trinucleotide RepeatsABSTRACT
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder generally presenting with intention tremor and gait ataxia, but with a growing list of co-morbid medical conditions including hypothyroidism, hypertension, peripheral neuropathy, and cognitive decline. The pathological hallmark of FXTAS is the presence of intranuclear inclusions in both neurons and astroglia. However, it is unknown to what extent such inclusions are present outside the central nervous system (CNS). To address this issue, we surveyed non-CNS organs in ten human cases with FXTAS and in a CGG repeat knock-in (CGG KI) mouse model known to possess neuronal and astroglial inclusions. We find inclusions in multiple tissues from FXTAS cases and CGG KI mice, including pancreas, thyroid, adrenal gland, gastrointestinal, pituitary gland, pineal gland, heart, and mitral valve, as well as throughout the associated autonomic ganglia. Inclusions were observed in the testes, epididymis, and kidney of FXTAS cases, but were not observed in mice. These observations demonstrate extensive involvement of the peripheral nervous system and systemic organs. The finding of intranuclear inclusions in non-CNS somatic organ systems, throughout the PNS, and in the enteric nervous system of both FXTAS cases as well as CGG KI mice suggests that these tissues may serve as potential sites to evaluate early intervention strategies or be used as diagnostic factors.
Subject(s)
Ataxia/pathology , Fragile X Syndrome/genetics , Fragile X Syndrome/pathology , Genetic Carrier Screening , Tremor/pathology , Aged , Aged, 80 and over , Animals , Ataxia/genetics , Disease Models, Animal , Female , Fragile X Mental Retardation Protein/genetics , Gene Knock-In Techniques , Humans , Male , Mice , Mice, Mutant Strains , Organ Specificity/genetics , Tremor/geneticsABSTRACT
The FMR1 gene is polymorphic for the length of CGG trinucleotide repeat expansions in the 5' untranslated region. Premutation (55-200 CGG repeats) and full-mutation (>200 CGG repeats) alleles give rise to their respective disorders by different pathogenic mechanisms: RNA gain-of-function toxicity leads to fragile X-associated tremor/ataxia syndrome in the premutation range, and transcriptional silencing and absence of fragile X mental retardation protein (FMRP) lead to fragile X syndrome in the full-mutation range. However, for the latter, incomplete silencing and/or size-mosaicism might result in some contribution to the disease process from residual messenger RNA production. To address this possibility, we examined the brains of 3 cases of fragile X syndrome for the presence of intranuclear inclusions in the hippocampal dentate gyrus. We identified low levels (0.1%-1.3%) of intranuclear inclusions in all 3 cases. Quantitative reverse transcription-polymerase chain reaction for FMR1 messenger RNA and immunofluorescence for FMRP revealed low but detectable levels of both RNA and protein in the 3 cases, consistent with the presence of small numbers of inclusions. The intranuclear inclusions were only present in FMRP-immunoreactive cells. The small numbers of inclusions and very low levels of both FMR1 RNA and protein suggest that the clinical course in these 3 subjects would not have been influenced by contributions from RNA toxicity.