Prenatal immune stress blunts microglia reactivity, impairing neurocircuitry.

Recent studies suggested that microglia, the primary brain immune cells, can affect circuit connectivity and neuronal function1,2. Microglia infiltrate the neuroepithelium early in embryonic development and are maintained in the brain throughout adulthood3,4. Several maternal environmental factors-such as an aberrant microbiome, immune activation and poor nutrition-can influence prenatal brain development5,6. Nevertheless, it is unknown how changes in the prenatal environment instruct the developmental trajectory of infiltrating microglia, which in turn affect brain development and function. Here we show that, after maternal immune activation (MIA) in mice, microglia from the offspring have a long-lived decrease in immune reactivity (blunting) across the developmental trajectory. The blunted immune response was accompanied by changes in chromatin accessibility and reduced transcription factor occupancy of the open chromatin. Single-cell RNA-sequencing analysis revealed that MIA does not induce a distinct subpopulation but, rather, decreases the contribution to inflammatory microglia states. Prenatal replacement of microglia from MIA offspring with physiological infiltration of naive microglia ameliorated the immune blunting and restored a decrease in presynaptic vesicle release probability onto dopamine receptor type-two medium spiny neurons, indicating that aberrantly formed microglia due to an adverse prenatal environment affect the long-term microglia reactivity and proper striatal circuit development.

Nuclear GAPDH in cortical microglia mediates cellular stress-induced cognitive inflexibility.

We report a mechanism that underlies stress-induced cognitive inflexibility at the molecular level. In a mouse model under subacute cellular stress in which deficits in rule shifting tasks were elicited, the nuclear glyceraldehyde dehydrogenase (N-GAPDH) cascade was activated specifically in microglia in the prelimbic cortex. The cognitive deficits were normalized with a pharmacological intervention with a compound (the RR compound) that selectively blocked the initiation of N-GAPDH cascade without affecting glycolytic activity. The normalization was also observed with a microglia-specific genetic intervention targeting the N-GAPDH cascade. At the mechanistic levels, the microglial secretion of High-Mobility Group Box (HMGB), which is known to bind with and regulate the NMDA-type glutamate receptors, was elevated. Consequently, the hyperactivation of the prelimbic layer 5 excitatory neurons, a neural substrate for cognitive inflexibility, was also observed. The upregulation of the microglial HMGB signaling and neuronal hyperactivation were normalized by the pharmacological and microglia-specific genetic interventions. Taken together, we show a pivotal role of cortical microglia and microglia-neuron interaction in stress-induced cognitive inflexibility. We underscore the N-GAPDH cascade in microglia, which causally mediates stress-induced cognitive alteration.

A longitudinal characterization of the adaptive and behavioral profile in Sotos syndrome.

Delineation of a developmental and behavioral trajectory is a key-topic in the context of a genetic syndrome. Short- and long-term implications concerning school outcome, independent living, and working opportunities are strictly linked to the cognitive and behavioral profile of an individual. For the first time, we present a longitudinal characterization of the adaptive and behavioral profile of a pediatric sample of 32 individuals with Sotos Syndrome (SoS) (18 males, 14 females; mean age 9.7 ± 4 years, eight carrying the NSD1 5q35 microdeletion and 24 with an intragenic mutation). We performed two clinical assessments: at baseline (T0) and at distance evaluation (T1) of adaptive and behavioral skills with a mean distance of 1.56 ± 0.95 years among timepoints. Our study reports a stability over the years-meant as lack of statistically significant clinical worsening or improvement-of both adaptive and behavioral skills investigated, regardless the level of Intellectual Quotient and chronological age at baseline. However, participants who did not discontinue intervention among T0 and T1, were characterized by a better clinical profile in terms of adaptive skills and behavioral profile at distance, emphasizing that uninterrupted intervention positively contributes to the developmental trajectory.

Developmental Stressors Induce Innate Immune Memory in Microglia and Contribute to Disease Risk.

Many types of stressors have an impact on brain development, function, and disease susceptibility including immune stressors, psychosocial stressors, and exposure to drugs of abuse. We propose that these diverse developmental stressors may utilize a common mechanism that underlies impaired cognitive function and neurodevelopmental disorders such as schizophrenia, autism, and mood disorders that can develop in later life as a result of developmental stressors. While these stressors are directed at critical developmental windows, their impacts are long-lasting. Immune activation is a shared pathophysiology across several different developmental stressors and may thus be a targetable treatment to mitigate the later behavioral deficits. In this review, we explore different types of prenatal and perinatal stressors and their contribution to disease risk and underlying molecular mechanisms. We highlight the impact of developmental stressors on microglia biology because of their early infiltration into the brain, their critical role in brain development and function, and their long-lived status in the brain throughout life. Furthermore, we introduce innate immune memory as a potential underlying mechanism for developmental stressors' impact on disease. Finally, we highlight the molecular and epigenetic reprogramming that is known to underlie innate immune memory and explain how similar molecular mechanisms may be at work for cells to retain a long-term perturbation after exposure to developmental stressors.

Comparative analysis of the standard PCR-Based Replicon Typing (PBRT) with the commercial PBRT-KIT.

Plasmids are the main vectors of resistance and virulence genes in Enterobacteriaceae and plasmid typing is essential for the analysis of evolution, epidemiology and spread of antibacterial resistance. The PCR-Based Replicon Typing (PBRT), developed by Carattoli et al. in 2005, was an efficient method for plasmid identification and typing in Enterobacteriaceae. The 2005 PBRT scheme detected 18 replicons in 8 PCR reactions. Recently, the identification of novel replicons and plasmid types requested an update of the PBRT scheme. A commercial PBRT-KIT was devised for the identification of 28 different replicons in 8 multiplex PCRs. Here we report sensitivity and specificity of the PBRT-KIT carried out in comparison with the 2005 PBRT. The analysis of plasmid content was performed on forty-two enterobacterial strains from different sources, containing different replicon content. The 2005 PBRT identified replicons in 76.2% of the strains. The PBRT-KIT detected replicons in 100% of the analyzed strains, demonstrating increasing sensitivity and specificity of the commercial test with respect to the former 2005 PBRT scheme.

Presence of Escherichia coli O157, Salmonella spp., and Listeria monocytogenes in Raw Ovine Milk Destined for Cheese Production and Evaluation of the Equivalence Between the Analytical Methods Applied.

Italy is one of the main producers and exporters of cheese made from unpasteurized sheep milk. Since raw milk and its derived products are known sources of human infections, cheese produced from raw sheep milk could pose a microbiological threat to public health. Hence, the objectives of the study were: to characterize the potential risk of the presence of pathogens Escherichia coli O157, Listeria monocytogenes, and Salmonella in raw ovine milk destined for cheese production obtained from all the sheep farms (n = 24) in the Marches region (Central Italy) that directly transform raw milk into cheeses and to evaluate the equivalence between the analytical methods applied. A three-step molecular method (simultaneous culture enrichment, species-specific DNA magnetic isolation, and multiplex real-time polymerase chain reaction) was used for milk (n = 143) and cheese (n = 5) analysis over a 3-year period. L. monocytogenes was not detected on any of the farms, while E. coli O157 was found on three farms, although only using the molecular method. Four farms tested positive for Salmonella spp., and Salmonella enterica subsp. diarizonae serovar 61:k:1,5,7 was isolated in one of those cases. This information highlights the need to develop preventative measures to guarantee a high level of consumer safety for this specific product line, and the molecular method could be a time-saving and sensitive tool to be used in routine diagnosis.

Unique toxin profile of a Mediterranean Ostreopsis cf. ovata strain: HR LC-MS(n) characterization of ovatoxin-f, a new palytoxin congener.

Currently, the benthic dinoflagellate Ostreopsis cf. ovata represents a serious concern to human health in the whole Mediterranean basin due to the production of palytoxin congeners, a putative palytoxin and ovatoxins (ovatoxin-a, -b, -c, -d/-e), listed among the most potent marine toxins. High resolution liquid chromatography-mass spectrometry (HR LC-MS) based investigation of a North Western Adriatic strain of Ostreopsis cf. ovata collected at Portonovo (Italy) in 2008 is reported herein. Toxin profile was different from those previously reported for other O. cf. ovata, both qualitatively and quantitatively. For the first time, ovatoxin-a did not dominate the toxin profile, and a new palytoxin congener, here named ovatoxin-f, was detected. Ovatoxin-f and its elemental formula present C(2)H(4) more than ovatoxin-a. HR CID MS(n) experiments allowed us to restrict structural differences between ovatoxin-a and -f to the region between C-95 and C-102, a region not previously been described to be modified in other palytoxins. Ovatoxin-f represents the major component of the toxin profile of the analyzed strain accounting for 50% of the total toxin content, while ovatoxin-a, the dominant toxin in most of the Mediterranean O. cf. ovata strains we have analyzed so far, is the second major component of the toxin profile (23%). Thus, the presence of ovatoxin-f should be taken into account when monitoring programs for palytoxin-like compounds in microalgae and/or seawater are carried out.

Maternal Multiple Sclerosis and Offspring's Cognitive and Behavioral Development: What Do We Know until Now?

Multiple Sclerosis (MS) is a chronic pathological condition representing one of the main causes of neurological disability in the female young population. MS, as an immune disorder, could impact fetus development, and, considering the need for and the possibility of pharmacological treatment during pregnancy, the possible influence of medication on developmental trajectories represents a topic of great interest. We provide an overview of the available literature on the influence of maternal Multiple Sclerosis on offspring cognitive and behavioral development. A study was conducted on Pubmed, Medline and Google Scholar, considering empirical studies and reviews exclusively in the English language. Maternal MS appears not to be associated with emotional and behavioral problems, as evaluated through retrospective studies. However, a specific cognitive and behavioral phenotype, through the administration of standardized instruments, has not been delineated yet. Available studies on the topic are characterized by poor methodology and do not lead to conclusions. This overview highlights implications for further longitudinal studies which should delineate offspring developmental trajectories, taking into consideration maternal confounding factors and the exposure to pharmacological treatment in pregnancy.

Maternal Perinatal Depression and Risk of Neurodevelopmental Disorders in Offspring: Preliminary Results from the SOS MOOD Project.

The latest research is attempting to define whether there may be an association between maternal Perinatal Depression (PD), the use of psychotropic medications during pregnancy, and a higher risk of neurodevelopmental disorders in children, including Autism Spectrum Disorder (ASD). A better understanding of the relation between PD and ASD is a key element to develop early interventions. This study has been developed in the context of the SOS MOOD project. Its aim is to evaluate the possible impact of maternal PD on the child's cognitive and behavioral phenotype with a focus on ASD. Women included in the project were screened during pregnancy (1st, 2nd trimester) for PD-categorized as affected or not-and if necessary were prescribed pharmacological therapy; offspring of both groups of women underwent at a mean age of 43 months a standardized neuropsychiatric evaluation of developmental and cognitive skills, behavioral problems, autism symptoms and parental stress. Preliminary results on 59 women and 59 children do not suggest significant long-term effects of maternal PD on offspring's development and behavior. Nonetheless further studies on wider samples are necessary in order to confirm such results and disentangle the role of possible confounding factors associated to the maternal illness.

Carriage of Carbapenem-Resistant Enterobacterales in Adult Patients Admitted to a University Hospital in Italy.

The emerging spread of carbapenemase-producing Enterobacterales (CPE) strains, in particular, Klebsiella pneumoniae and Escherichia coli, has become a significant threat to hospitalized patients. Carbapenemase genes are frequently located on plasmids than can be exchanged among clonal strains, increasing the antibiotic resistance rate. The aim of this study was to determine the prevalence of CPE in patients upon their admission and to analyze selected associated factors. An investigation of the antibiotic resistance and genetic features of circulating CPE was carried out. Phenotypic tests and molecular typing were performed on 48 carbapenemase-producing strains of K. pneumoniae and E. coli collected from rectal swabs of adult patients. Carbapenem-resistance was confirmed by PCR detection of resistance genes. All strains were analyzed by PCR-based replicon typing (PBRT) and multilocus sequence typing (MLST) was performed on a representative isolate of each PBRT profile. More than 50% of the strains were found to be multidrug-resistant, and the bla KPC gene was detected in all the isolates with the exception of an E. coli strain. A multireplicon status was observed, and the most prevalent profile was FIIK, FIB KQ (33%). MLST analysis revealed the prevalence of sequence type 512 (ST512). This study highlights the importance of screening patients upon their admission to limit the spread of CRE in hospitals.

Plasmid Replicon Typing of Antibiotic-Resistant Escherichia coli From Clams and Marine Sediments.

Unlike human isolates, environmental Escherichia coli isolates have not been thoroughly investigated for the diversity and transferability of antibiotic-resistant plasmids. In this study, antibiotic-resistant strains from marine sediment (n = 50) and clams (n = 53) were analyzed (i) for their plasmid content using a PCR-based plasmid replicon typing (PBRT) kit and (ii) for the transferability of plasmid-associated antibiotic resistance (AR) traits by mating experiments. Fifteen of the thirty replicons targeted by the PBRT kit were detected in the isolates; 8/15 were identified in both sediment and clam isolates, although at different frequencies. The most frequent replicons in sediment (74%) and in clam strains (66%) alike, were FIA, FIB, or FII, which are associated with the IncF group, followed by the I1α replicon, which was more frequent in clam (24.5%) than in sediment (10%) strains. More than 50% of the strains contained multiple replicons; although 15 were untypable, S1-PFGE analysis demonstrated that 14/15 carried no plasmids. All cryptic strains were successfully typed and were positive for IncF or IncI replicons. Antibiotic-resistant strains accounted for 63% of all isolates and were significantly (p < 0.05) more frequent in phylogroup A. Most (35%) multidrug-resistant (MDR) strains belonged to phylogroup A, too. Although 25/26 MDR strains were positive for IncF plasmids (the exception being a clam strain), the FII-FIB rep combination was predominant (63%) among the sediment isolates, whereas most clam isolates (40%) carried the FII replicon alone. In mating experiments, selected MDR strains carrying FIB, FII, and I1α replicons, used as the donors, transferred multiple ARs together with the IncF or IncI plasmids at high frequency. Since IncI plasmids are common in E. coli and Salmonella enterica isolates from poultry, our findings suggest an animal origin to the E. coli clam strains carrying IncI plasmids. They also suggest a role for IncI plasmids in the spread of ARs among environmental Enterobacteriaceae and, through the food chain, to human isolates. In conclusion, the PBRT kit proved to be a useful tool to identify plasmids carrying antibiotic-resistant genes and to shed light on the factors underpinning their diffusion.

Evaluation of PCR-based methods for the identification of enteroaggregative hemorrhagic Escherichia coli in sprouts.

In this study real-time PCR assays were evaluated for the detection of enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 in artificially contaminated mung bean and/alfalfa sprouts inoculated with 1, 10, and 100 CFU of EAHEC O104:H4 per 25 g sample (20, 10, and 2 replicates respectively). After selective culture enrichment the samples were tested using commercial real-time PCR kits detecting aggR/aaiC, stx/eae, and wzxO104. Using the commercial real-time PCR kits, the artificially contaminated samples were detected in the range of 75-80% positive results when contaminated with approximately 1 CFU, and 100% at 10 and 100 CFU. Microbiological detection employing O104-specific immunomagnetic capture and plating onto chromogenic media (modified Rainbow Agar and CHROMagar STEC) and confirmation by latex agglutination and PCR gave similar results (Cohen's kappa value between 0.61 and 1). In addition, the real-time PCR assay targeting the aggR and aaiC genes, indicative of enteroaggregative Escherichia coli (EAggEC), was tested against a panel of 60 bacterial strains and demonstrated 100% exclusivity (54 strains) and 100% inclusivity (6 strains). This study demonstrates the efficacy of the real-time PCR assays for the specific and sensitive detection of EAHEC from spouts.

A negative feedback mechanism links UBC gene expression to ubiquitin levels by affecting RNA splicing rather than transcription.

UBC gene plays a critical role in maintaining ubiquitin (Ub) homeostasis. It is upregulated under stress conditions, and herein we report that it is downregulated upon Ub overexpression. Downregulation occurs in a dose-dependent manner, suggesting the existence of a fine-tuned Ub sensing mechanism. This "sensor" requires a conjugation competent ubiquitin to detect Ub levels. Searching the sensor among the transcription factors involved in basal and stress-induced UBC gene expression was unsuccessful. Neither HSF1 and HSF2, nor Sp1 and YY1 are affected by the increased Ub levels. Moreover, mutagenesis of their binding sites in the UBC promoter-driven reporter constructs does not impair the downmodulation effect. Epigenetic studies show that H2A and H2B ubiquitination within the UBC promoter region is unchanged upon ubiquitin overexpression. Noteworthy, quantification of nascent RNA molecules excludes that the downmodulation arises in the transcription initiation step, rather pointing towards a post-transcriptional mechanism. Indeed, a significantly higher fraction of unspliced UBC mRNA is detected in ubiquitin overexpressing cells, compared to empty vector transfected cells. Our findings suggest how increasing cellular ubiquitin levels may control the expression of UBC gene by negatively affecting the splicing of its pre-mRNA, providing a straightforward feedback strategy for the homeostatic control of ubiquitin pools.

Rapid and simultaneous detection of Salmonella spp., Escherichia coli O157, and Listeria monocytogenes by magnetic capture hybridization and multiplex real-time PCR.

The application of rapid, specific, and sensitive methods for pathogen detection and quantification is very advantageous in diagnosis of human pathogens in several applications, including food analysis. The aim of this study was the evaluation of a method for the multiplexed detection and quantification of three significant foodborne pathogenic species (Escherichia coli O157, Salmonella spp., and Listeria monocytogenes). The assay combines specific DNA extraction by multiplex magnetic capture hybridization (mMCH) with multiplex real-time PCR. The amplification assay showed linearity in the range 106-10 genomic units (GU)/PCR for each co-amplified species. The sensitivity corresponded to 1 GU/PCR for E. coli O157 and L. monocytogenes, and 10 GU/PCR for Salmonella spp. The immobilization process and the hybrid capture of the MCH showed good efficiency and reproducibility for all targets, allowing the combination in equal amounts of the different nanoparticle types in mMCH. MCH and mMCH efficiencies were similar. The detection limit of the method was 10 CFU in samples with individual pathogens and 102 CFU in samples with combination of the three pathogens in unequal amounts (amount's differences of 2 or 3 log). In conclusion, this multiplex molecular platform can be applied to determine the presence of target species in food samples after culture enrichment. In this way, this method could be a time-saving and sensitive tool to be used in routine diagnosis.

Detection of Shiga toxin-producing Escherichia coli (STEC) in ground beef and bean sprouts: Evaluation of culture enrichment conditions.

The main purpose of this work was to evaluate culture enrichment conditions, with particular regard to those reported in ISO/TS 13136:2012, for STEC detection in food. The culture media evaluated included mTSB with novobiocin 0-16mg/l (mTSB+N0-16) or acriflavin 12mg/l (mTSB+A12); BPW; mBPWp with acriflavin 10mg/l, cefsulodin 10mg/l, vancomycin 8mg/l (mBPWp+ACV); and mBPWp with cefsulodin 10mg/l, vancomycin 8mg/l (mBPWp+CV). They were used for the growth of STEC O157, O26, O103, O111, O145 and O104 in pure cultures or in artificially contaminated food matrices (ground beef, mung bean sprouts). STEC detection was accomplished using commercially available multiplex real-time PCR assays targeting stx1-stx2 and eae, and serogroup-associated genes. More rapid multiplication of STEC in pure cultures occurred in mBPWp+CV, while an inhibitory effect of novobiocin and acriflavin was observed for some STEC serogroups in media with these selective agents. mBPWp+CV allowed the detection of all serogroups in bean sprouts when inoculated at levels as low as 1CFU/25g. A reduced novobiocin concentration of 2mg/l in mTSB was required for STEC detection in ground beef samples. A temperature of 42°C for the entire duration of the enrichment or 44°C after an initial phase of 6h at 37°C was important to limit the multiplication of non-target bacteria. Results of this study suggest that media and protocols should be adapted to the food being analyzed, since protocols provided in official reference methods may produce insufficient sensitivity.

Validation and application of a quantitative real-time PCR assay to detect common wheat adulteration of durum wheat for pasta production.

Pasta is the Italian product par excellence and it is now popular worldwide. Pasta of a superior quality is made with pure durum wheat. In Italy, addition of Triticum aestivum (common wheat) during manufacturing is not allowed and, without adequate labeling, its presence is considered an adulteration. PCR-related techniques can be employed for the detection of common wheat contaminations. In this work, we demonstrated that a previously published method for the detection of T. aestivum, based on the gliadin gene, is inadequate. Moreover, a new molecular method, based on DNA extraction from semolina and real-time PCR determination of T. aestivum in Triticum spp., was validated. This multiplex real-time PCR, based on the dual-labeled probe strategy, guarantees target detection specificity and sensitivity in a short period of time. Moreover, the molecular analysis of common wheat contamination in commercial wheat and flours is described for the first time.

Prevalence and antibiotic resistance of Pseudomonas aeruginosa in water samples in central Italy and molecular characterization of oprD in imipenem resistant isolates.

SCOPE: This study aimed to analyse the prevalence, antibiotic resistance and genetic relatedness of P. aeruginosa isolates obtained from potable and recreational water samples (n. 8,351) collected from different settings (swimming pools, n. 207; healthcare facilities, n 1,684; accommodation facilities, n. 1,518; municipal waterworks, n. 4,500; residential buildings, n. 235). Possible mechanisms underlying resistance to imipenem, with particular focus on those involving oprD-based uptake, were also explored. METHODS AND RESULTS: Isolation and identification of Pseudomonas aeruginosa was performed according to the standardized procedure UNI EN ISO 16266:2008 followed by PCR confirmation. Antibiotic Susceptibility testing was conducted according to EUCAST standardized disk diffusion method. Genetic relatedness of strains was carried out by RAPD. The sequence of the oprD gene was analyzed by standard method. Fifty-three samples (0.63%) were positive for P. aeruginosa, of which 10/207 (4.83%) were from swimming pools. Five isolates (9.43%) were resistant to imipenem, one to Ticarcillin + Clavulanate, one to both Piperacillin and Ticarcillin + Clavulanate. The highest isolation rate of imipenem resistant P. aeruginosa was observed in swimming pool water. Identical RAPD profiles were found in isolates from the same location in the same year or even in different years. CONCLUSIONS: Imipenem resistant strains were identified as carbapenemase-negative and resistance has been associated with inactivating mutations within the oprD gene, with a concomitant loss of porin. RAPD results proved that a water system can remain colonized by one strain for long periods and the contamination may be difficult to eradicate. This study has revealed the presence of P. aeruginosa in different water samples, including resistant strains, especially in swimming pools, and confirmed the role of porins as a contributing factor in carbapenem resistance in Gram-negative bacteria.

Effect of farm characteristics and practices on hygienic quality of ovine raw milk used for artisan cheese production in central Italy.

A survey on ovine dairy farms directly transforming own-produced milk, in the Italian Marche region, was carried out to assess flock and milking practices that may influence milk hygienic-sanitary conditions. A census survey established that 24 dairy farms were located in this region. Bulk milk samples were collected throughout the milking period in each dairy farm in 2013. Analyzed variables were: (i) chemical parameters such as fat, protein and lactose content, dry matter and pH; and (ii) total bacterial (TBC) and somatic cell counts (SCC). Chemical parameter values were in agreement with published data while, geometric mean (GM) log10 SCC was 5.91 and TBC GM was 57 978 colony forming units/mL, in compliance with Eropean Union criteria. A positive correlation was found between SCC and TBC when GMs of all farm data were considered (Spearman's rho = 0.7925; P = 0.0001). Statistical analysis did not show significant correlation between SCC or TBC GM and dairy farm principal characteristics. Although SCC levels detected in the present study should suggest the need to implement mastitis control programs, Marche's dairy sheep flocks revealed a good hygienic condition level. This is an important aspect in implementing safety for end users of the final product.

Dynamic transcription of ubiquitin genes under basal and stressful conditions and new insights into the multiple UBC transcript variants.

Ubiquitin (Ub) is a small 76-amino acid protein that is engaged in many different pathways within the cell, including protein turnover. During proteotoxic stress, when the demand of clearing damaged/misfolded proteins strongly increases, cells activate Ub gene transcription to face the need of extra ubiquitin. This paper shows the contribution of the four ubiquitin coding genes (UBB, UBC, UBA52, RPS27A) to the ubiquitin RNA pool under basal and stressful conditions. Our results reveal that UBC and RPS27A represent the major fraction of the Ub transcriptome in different cell lines, but when converted to the coding potential, polyubiquitin genes UBC and UBB mainly contribute to determine the intracellular ubiquitin content under basal conditions. Both the polyubiquitin genes UBB and UBC are upregulated upon proteasome inhibition and oxidative stress, with markedly higher responses from the UBC promoter. A similar output, with lower fold-inductions, is detected in heat-stressed cells, with UBC acting as the main contributor to thermotolerance. By contrast, upon these stressors, the levels of UBA52 and RPS27A mRNAs remain unchanged. Remarkably, UV irradiation fails to induce Ub gene transcription, but rather seems to act at the post-transcriptional level, by stabilizing ubiquitin mRNAs at UV doses which induce rapid degradation of other RNA molecules. Moreover, the evidence that the UBC core promoter contains multiple transcription start sites and their responsiveness to stress, is here reported for the first time.