Human follicular mites: Ectoparasites becoming symbionts.

Most humans carry mites in the hair follicles of their skin for their entire lives. Follicular mites are the only metazoans tha continuously live on humans. We propose that Demodex folliculorum (Acari) represents a transitional stage from a host-injuring obligate parasite to an obligate symbiont. Here, we describe the profound impact of this transition on the genome and physiology of the mite. Genome sequencing revealed that the permanent host association of D. folliculorum led to an extensive genome reduction through relaxed selection and genetic drift, resulting in the smallest number of protein-coding genes yet identified among panarthropods. Confocal microscopy revealed that this gene loss coincided with an extreme reduction in the number of cells. Single uninucleate muscle cells are sufficient to operate each of the three segments that form each walking leg. While it has been assumed that the reduction of the cell number in parasites starts early in development, we identified a greater total number of cells in the last developmental stage (nymph) than in the terminal adult stage, suggesting that reduction starts at the adult or ultimate stage of development. This is the first evolutionary step in an arthropod species adopting a reductive, parasitic or endosymbiotic lifestyle. Somatic nuclei show underreplication at the diploid stage. Novel eye structures or photoreceptors as well as a unique human host melatonin-guided day/night rhythm are proposed for the first time. The loss of DNA repair genes coupled with extreme endogamy might have set this mite species on an evolutionary dead-end trajectory.

Starkeya nomas sp. nov., a prosthecate and budding bacterium isolated from an immunocompromized patient.

Strain HF14-78462T is an environmental bacterium found in clinical samples from an immunocompromized patient in 2014 at Hospital Universitari i Politècnic La Fe (Valencia, Spain). Phenotypically, strain HF14-78462T cells were Gram-stain-negative, aerobic, non-spore forming and non-motile small rods which formed mucous and whitish-translucent colonies when incubated at 20-36 °C. Phylogenetic analyses based on the 16S rRNA genes and the whole genomes of closest sequenced relatives confirmed that strain HF14-78462T is affiliated with the genus Starkeya. The strain was oxidase, catalase and urease positive; but indole, lysine decarboxylase, ornithine decarboxylase and DNase negative, did not produce H2S and was able to utilize a wide variety of carbon sources including acetamide, adonitol, amygdalin, l-arabinose, citric acid, glucose, mannitol and melibiose. Unlike Starkeya novella and Starkeya koreensis, strain HF14-78462T failed to grow in thiosulphate-oxidizing media and had a narrower temperature growth range. Its genome was characterized by a size of 4.83 Mbp and a C+G content of 67.75 mol%. Major fatty acids were C18:1 ω7c, cyclo C19 : 0 and C16 : 0, its polar acids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an aminophospholipid; while the ubiquinones were Q9 (1.8 %) and Q10 (98.2 %). Digital DNA-DNA hybridization values were 41 and 41.4 against S. novella and S. koreensis, respectively, while average nucleotide identity values were around 84 %. Phenotypic, average nucleotide identity and phylogenomic comparative studies suggest that strain HF14-78462T is a new representative of the genus Starkeya and the name Starkeya nomas sp. nov. is proposed. The type strain is HF14-78462T (=CECT 30124T=LMG 31874T).

Whole-Genome Analysis Surveillance of Influenza A Virus Resistance to Polymerase Complex Inhibitors in Eastern Spain from 2016 to 2019.

Molecular surveillance by whole-genome sequencing was used to monitor the susceptibility of circulating influenza A viruses to three polymerase complex inhibitors. A total of 12 resistance substitutions were found among 285 genomes analyzed, but none were associated with high levels of resistance. Natural resistance to these influenza A antivirals is currently uncommon.

Impact of including two types of destoned olive cakes in pigs' diets on fecal bacterial composition and study of the relationship between fecal microbiota, feed efficiency, gut fermentation, and gaseous emissions.

The microbial population in the pig's gastrointestinal tract can be influenced by incorporating fibrous by-products into the diets. This study investigated the impact of including two types of dried olive cake (OC) in pigs' diets on fecal bacterial composition. The correlation between fecal microbiota and growth performance, nutrient digestibility, gut fermentation pattern and slurry gas emissions was also evaluated. Thirty male Pietrain x (Landrace x Large white) pigs (47.9 ± 4.21 kg) were assigned to three groups: a control group (C), a group fed a diet with 20% partially defatted OC (20PDOC), and a group fed a diet with 20% cyclone OC (20COC) for 21 days. Fecal samples collected before and after providing the experimental diets were analyzed for the V3-V4 region of the 16S rRNA gene. Pigs were weighed, and feed intake was recorded throughout the study. Potential ammonia and methane emissions from slurry were measured. No significant differences in alpha diversity indexes were found. The taxonomic analysis revealed that Firmicutes and Bacteroidota phyla were dominant at the phylum level across all groups. Differential abundance analysis using ALDEx showed significant differences among groups for various bacteria at the phylum, genus, and species levels at the end of the experiment. Pigs from 20PDOC and 20COC groups exhibited increased abundances of health-promoting bacteria, such as Plactomycetota at the phylum level and Allisonella and an unidentified genus from the Eggerthellaceae family at the genus level. These changes influenced short-chain fatty acids' (SCFA) concentration in slurries, leading to greater acetic, butyric, caproic and heptanoic acids in OC-fed groups, especially 20COC pigs. A volatility analysis revealed significant positive correlations (p < 0.05) between Uncultured_Bacteroidales and Unculured_Selenomonadaceae and energy digestibility. Monoglobus and Desulfovibrio showed a positive significant (p < 0.05) correlation with total SCFA, indicating a high impact on gut fermentation. However, growth performance parameters and potential gas emission displayed no significant correlations with a specific bacterial genus. In conclusion, our results suggest that OC inclusion into pig diets could positively modulate and contribute to the gut microbiota's favorable composition and functionality. Also, nutrient digestibility and gut fermentation patterns can be associated with specific microbial populations.

Diabetic Ketoacidosis in Type 1 Diabetes Onset in Latin American Children.

OBJECTIVE: To describe the patterns of diabetic ketoacidosis (DKA) occurrence in children newly diagnosed with type 1 diabetes (T1DM) across several Latin American pediatric diabetes centers from 2018 to 2022. METHODS: A retrospective chart review included children under 18 with new-onset T1DM from 30 Latin American pediatric diabetes centers (Argentina, Chile, and Peru) between 30 December 2018 and 30 December 2022. Multiple logistic regression models examined the relationships between age, gender, medical insurance, BMI, and DKA at new-onset T1DM. As far as we know, there are no large studies in Latin American countries exploring the patterns of DKA in new-onset T1DM. RESULTS: A total of 2,026 (983 females) children, median age 9.12 (5.8 -11.7) years with new-onset-T1DM were included. Approximately 50% had no medical insurance. Mean glucose values were 467 mg/dL, pH 7.21, bicarbonate 13 mEq/L, HbA1c 11.3%, and BMI 18. The frequency of DKA was 1,229 (60.7%), out of which only 447 (36%) were severe. There was a significant decrease in the frequency of DKA as age increased: 373 (70.2%) in children under 6, 639 (61.6%) in those between 6 and 12, 217 and (47.5%) in those over 12. Children with medical insurance (58.8%) had a significantly lower frequency of DKA than those without (62.7%). The multiple logistic regression models showed that DKA was significantly and inversely associated with age [OR, 0.72 (95% CI 0.60-0.86)], BMI [OR, 0.95 (95% CI 0.92-0.99)], and medical insurance [OR, 0.75 (95% CI 0.60-0.94)] adjusted for sex. CONCLUSION: Latin American children with new-onset T1DM exhibited a substantial occurrence of DKA. Younger ages and the lack of medical insurance were significantly associated with DKA in new-onset T1DM.

Characterization of the Fecal and Mucosa-Associated Microbiota in Dogs with Chronic Inflammatory Enteropathy.

Canine chronic inflammatory enteropathy implicates multifactorial pathogenesis where immunological dysregulation and gut microbiota changes have a central role. Most sequencing-based taxonomic studies have been focused on the fecal microbiota. However, the analysis of these samples does not provide complete information regarding the composition of the small intestine affected by this canine disease. Therefore, in this study, we aimed to characterize the intestinal bacterial microbiota in dogs with inflammatory bowel disease (IBD) (n = 34) by means of duodenal biopsies and fecal samples collected at the time of the diagnosis and to compare those to a group of healthy dogs (n = 12) using the 16S ribosomal RNA (16S rRNA) gene-targeted sequencing (Illumina MiSeq platform). Our study showed that IBD dogs presented differences in the fecal bacterial communities when compared with healthy dogs, with a lower relative abundance of Prevotellaceae (p = 0.005), Prevotella (p = 0.002), and Prevotellaceae Ga6A1 group (0.006); Erysipelotrichales (p = 0.019), Candidatus Stoquefichus (p < 0.001), Erysipelotrichaceae (p = 0.011), and Allobaculum (p = 0.003); Lachnospiraceae NK4A136 group (p = 0.015), Sellimonas (p = 0.042), Oscillospirales (p = 0.037), Oscillospiraceae UCG-005 (p < 0.001), Faecalibacterium (p = 0.028), and Fournierella (p = 0.034); Acidaminococcales, Acidaminococcaceae, and Phascolarctobacterium (p = 0.001); Aeromonadales (p = 0.026), Succinivibrionaceae (p = 0.037), and Succinivibrio (p = 0.031). On the other hand, a higher relative abundance of Enterococcaceae (Enterococcus; p = 0.003), Streptococcaceae (Streptococcus, p = 0.021), Enterobacterales (p = 0.027), Enterobacteriaceae (p = 0.008), and Escherichia-Shigella (p = 0.011) was detected. Moreover, when evaluating α-diversity, the dogs with IBD showed lower diversity in terms of richness and abundance of species (observed species [p = 0.031] and Shannon index [p = 0.039]). Furthermore, fecal microbiota in dogs with IBD was significantly different from healthy dogs (p = 0.006). However, only a few taxa relative abundance shifts (lower Rubrobacteria, Rubrobacterales, Rubrobacteriaceae, and Rubrobacter [p = 0.002]; Cyanobacteria [p = 0.010], Vampirivibrionia, Obscuribacterales, and Obscuribacteraceae [p = 0.005]; Neisseriaceae [p = 0.004] and Conchiformibius [p = 0.003]) were observed when assessing duodenal-associated microbiota of dogs with IBD. Thus, even if the bowel inflammation mainly affects the small intestine in the IBD-affected dogs of the study, fecal specimens may constitute a better sample due not only to their easy availability but also in terms of searching for bacterial taxa as biomarkers for canine IBD. The use of different diets in the study can also have a partial influence on the microbiota composition. Future studies encompassing multi-omics approaches should evaluate the functionality in both levels to unravel the pathophysiology of canine IBD.

Complete Genome Sequences of Two Lytic Phages of Salmonella enterica Isolated from Wastewater in Ecuador.

Salmonella enterica is one of the most common causes of foodborne diseases. Bacteriophages provide an option to reduce the presence of Salmonella. Here, we describe the isolation of two lytic Salmonella bacteriophages. The complete genomes were annotated and show similarity to that of the lytic phage NBSal001, in the Drexlerviridae family.

[Obesity and risk factors for metabolic syndrome in young people with type 1 diabetes]. / Obesidad y factores de riesgo del síndrome metabólico en jóvenes con diabetes tipo 1.

Changes in the clinical presentation of diabetes mellitus in childhood and adolescence associated with obesity have resulted in an overlap of the two most common types of diabetes with a greater clinical heterogeneity. In order to characterize the type of diabetes at onset and assess the effect of obesity, 50 children with diabetes were studied. The patients were divided into two groups according to their nutritional status at diagnosis (over-weight/obese vs. normal weight). Insulin reserve was evaluated by measuring basal C-peptide and stimulated C-peptide in response to a mixed meal (MMTT) as well as HLA-DQB1 genotype, antibodies, and family history of risk factors for metabolic disease. Of all 50 patients, 38% was overweight/obese, 84% had a positive family history of metabolic syndrome, 82% had positive antibodies, and 100% were positive for the high-risk HLA-DQB1 genotype. No significant differences were found in fasting C-peptide or glycemic index/C-peptide levels between the two groups. In the overweight/obese group C-peptide response to MMTT showed higher levels at 60 and 120 minutes (p = 0.02 and 0.03) and the area under the curve for C-peptide was also higher (1.77 ng / ml vs. 5.5 ng/ ml, p = 0.0007) than in the normal-weight group. In conclusion, overweight/obese patients with type 1A diabetes had a greater pancreatic reserve, suggesting that nutritional status may accelerate disease onset.

The Minimal Translation Machinery: What We Can Learn From Naturally and Experimentally Reduced Genomes.

The current theoretical proposals of minimal genomes have not attempted to outline the essential machinery for proper translation in cells. Here, we present a proposal of a minimal translation machinery based on (1) a comparative analysis of bacterial genomes of insects' endosymbionts using a machine learning classification algorithm, (2) the empiric genomic information obtained from Mycoplasma mycoides JCVI-syn3.0 the first minimal bacterial genome obtained by design and synthesis, and (3) a detailed functional analysis of the candidate genes based on essentiality according to the DEG database (Escherichia coli and Bacillus subtilis) and the literature. This proposed minimal translational machinery is composed by 142 genes which must be present in any synthetic prokaryotic cell designed for biotechnological purposes, 76.8% of which are shared with JCVI-syn3.0. Eight additional genes were manually included in the proposal for a proper and efficient translation.

Diabetes-related antibody-testing is a valuable screening tool for identifying monogenic diabetes - A survey from the worldwide SWEET registry.

AIMS: To evaluate access to screening tools for monogenic diabetes in paediatric diabetes centres across the world and its impact on diagnosis and clinical outcomes of children and youth with genetic forms of diabetes. METHODS: 79 centres from the SWEET diabetes registry including 53,207 children with diabetes participated in a survey on accessibility and use of diabetes related antibodies, c-peptide and genetic testing. RESULTS: 73, 63 and 62 participating centres had access to c-peptide, antibody and genetic testing, respectively. Access to antibody testing was associated with higher proportion of patients with rare forms of diabetes identified with monogenic diabetes (54 % versus 17 %, p = 0.01), lower average whole clinic HbA1c (7.7[Q1,Q2: 7.3-8.0]%/61[56-64]mmol/mol versus 9.2[8.6-10.0]%/77[70-86]mmol/mol, p < 0.001) and younger age at onset (8.3 [7.3-8.8] versus 9.7 [8.6-12.7] years p < 0.001). Additional access to c-peptide or genetic testing was not related to differences in age at onset or HbA1c outcome. CONCLUSIONS: Clinical suspicion and antibody testing are related to identification of different types of diabetes. Implementing access to comprehensive antibody screening may provide important information for selecting individuals for further genetic evaluation. In addition, worse overall clinical outcomes in centers with limited diagnostic capabilities indicate they may also need support for individualized diabetes management. TRIAL REGISTRATION: NCT04427189.

Characterization of Erwinia gerundensis A4, an Almond-Derived Plant Growth-Promoting Endophyte.

The rapidly increasing global population and anthropogenic climate change have created intense pressure on agricultural systems to produce increasingly more food under steadily challenging environmental conditions. Simultaneously, industrial agriculture is negatively affecting natural and agricultural ecosystems because of intensive irrigation and fertilization to fully utilize the potential of high-yielding cultivars. Growth-promoting microbes that increase stress tolerance and crop yield could be a useful tool for helping mitigate these problems. We investigated if commercially grown almonds might be a resource for plant colonizing bacteria with growth promotional traits that could be used to foster more productive and sustainable agricultural ecosystems. We isolated an endophytic bacterium from almond leaves that promotes growth of the model plant Arabidopsis thaliana. Genome sequencing revealed a novel Erwinia gerundensis strain (A4) that exhibits the ability to increase access to plant nutrients and to produce the stress-mitigating polyamine spermidine. Because E. gerundensis is known to be able to colonize diverse plant species including cereals and fruit trees, A4 may have the potential to be applied to a wide variety of crop systems.

MetNet: A two-level approach to reconstructing and comparing metabolic networks.

Metabolic pathway comparison and interaction between different species can detect important information for drug engineering and medical science. In the literature, proposals for reconstructing and comparing metabolic networks present two main problems: network reconstruction requires usually human intervention to integrate information from different sources and, in metabolic comparison, the size of the networks leads to a challenging computational problem. We propose to automatically reconstruct a metabolic network on the basis of KEGG database information. Our proposal relies on a two-level representation of the huge metabolic network: the first level is graph-based and depicts pathways as nodes and relations between pathways as edges; the second level represents each metabolic pathway in terms of its reactions content. The two-level representation complies with the KEGG database, which decomposes the metabolism of all the different organisms into "reference" pathways in a standardised way. On the basis of this two-level representation, we introduce some similarity measures for both levels. They allow for both a local comparison, pathway by pathway, and a global comparison of the entire metabolism. We developed a tool, MetNet, that implements the proposed methodology. MetNet makes it possible to automatically reconstruct the metabolic network of two organisms selected in KEGG and to compare their two networks both quantitatively and visually. We validate our methodology by presenting some experiments performed with MetNet.

Analysis of the Gut Microbiota: An Emerging Source of Biomarkers for Immune Checkpoint Blockade Therapy in Non-Small Cell Lung Cancer.

BACKGROUND: The human gut harbors around 1013-1014 microorganisms, collectively referred to as gut microbiota. Recent studies have found that the gut microbiota may have an impact on the interaction between immune regulation and anti-cancer immunotherapies. METHODS: In order to characterize the diversity and composition of commensal microbiota and its relationship with response to immune checkpoint blockade (ICB), 16S ribosomal DNA (rDNA) sequencing was performed on 69 stool samples from advanced non-small cell lung cancer (NSCLC) patients prior to treatment with ICB. RESULTS: The use of antibiotics and ICB-related skin toxicity were significantly associated with reduced gut microbiota diversity. However, antibiotics (ATB) usage was not related to low ICB efficacy. Phascolarctobacterium was enriched in patients with clinical benefit and correlated with prolonged progression-free survival, whereas Dialister was more represented in patients with progressive disease, and its higher relative abundance was associated with reduced progression-free survival and overall survival, with independent prognostic value in multivariate analysis. CONCLUSIONS: Our results corroborate the relation between the baseline gut microbiota composition and ICB clinical outcomes in advanced NSCLC patients, and provide novel potential predictive and prognostic biomarkers for immunotherapy in NSCLC.

The Metabolic Building Blocks of a Minimal Cell.

Defining the essential gene components for a system to be considered alive is a crucial step toward the synthesis of artificial life. Fifteen years ago, Gil and coworkers proposed the core of a putative minimal bacterial genome, which would provide the capability to achieve metabolic homeostasis, reproduce, and evolve to a bacterium in an ideally controlled environment. They also proposed a simplified metabolic chart capable of providing energy and basic components for a minimal living cell. For this work, we have identified the components of the minimal metabolic network based on the aforementioned studies, associated them to the KEGG database and, by applying the MetaDAG methodology, determined its Metabolic Building Blocks (MBB) and reconstructed its metabolic Directed Acyclic Graph (m-DAG). The reaction graph of this metabolic network consists of 80 compounds and 98 reactions, while its m-DAG has 36 MBBs. Additionally, we identified 12 essential reactions in the m-DAG that are critical for maintaining the connectivity of this network. In a similar manner, we reconstructed the m-DAG of JCVI-syn3.0, which is an artificially designed and manufactured viable cell whose genome arose by minimizing the one from Mycoplasma mycoides JCVI-syn1.0, and of "Candidatus Nasuia deltocephalinicola", the bacteria with the smallest natural genome known to date. The comparison of the m-DAGs derived from a theoretical, an artificial, and a natural genome denote slightly different lifestyles, with a consistent core metabolism. The MetaDAG methodology we employ uses homogeneous descriptors and identifiers from the KEGG database, so that comparisons between bacterial strains are not only easy but also suitable for many research fields. The modeling of m-DAGs based on minimal metabolisms can be the first step for the synthesis and manipulation of minimal cells.

An update on the Symbiotic Genomes Database (SymGenDB): a collection of metadata, genomic, genetic and protein sequences, orthologs and metabolic networks of symbiotic organisms.

The Symbiotic Genomes Database (SymGenDB; http://symbiogenomesdb.uv.es/) is a public resource of manually curated associations between organisms involved in symbiotic relationships, maintaining a catalog of completely sequenced/finished bacterial genomes exclusively. It originally consisted of three modules where users could search for the bacteria involved in a specific symbiotic relationship, their genomes and their genes (including their orthologs). In this update, we present an additional module that includes a representation of the metabolic network of each organism included in the database, as Directed Acyclic Graphs (MetaDAGs). This module provides unique opportunities to explore the metabolism of each individual organism and/or to evaluate the shared and joint metabolic capabilities of the organisms of the same genera included in our listing, allowing users to construct predictive analyses of metabolic associations and complementation between systems. We also report a ~25% increase in manually curated content in the database, i.e. bacterial genomes and their associations, with a final count of 2328 bacterial genomes associated to 498 hosts. We describe new querying possibilities for all the modules, as well as new display features for the MetaDAGs module, providing a relevant range of content and utility. This update continues to improve SymGenDB and can help elucidate the mechanisms by which organisms depend on each other.

Metformin, estrogen replacement therapy and gonadotropin inhibition fail to improve insulin sensitivity in a girl with aromatase deficiency.

BACKGROUND: Insulin resistance (IR), abnormal lipid profile, and other features of the metabolic syndrome have been described in CYP19 gene knockout mice and in aromatase-deficient adult men but not in prepubertal affected girls. AIMS: To study insulin sensitivity, as well as the effects of estrogen, metformin and GnRHa treatment on glucose homeostasis, in an aromatase-deficient girl. METHODS: Clinical, metabolic and hormonal follow-up data, from 8 to 12 years of age, is presented. RESULTS: At 9 years of age, IR (HOMA 5.6) and glucose intolerance was detected, along with high serum testosterone (2.28 nmol/l), androstenedione (4.92 nmol/l) and FSH (13.4 mIU/ml) levels. Estrogen replacement was ineffective to suppress gonadotropin and androgen levels, as well as IR. Under metformin therapy, she developed type 2 diabetes and acanthosis nigricans. GnRHa administration for 1 year resulted in marked decreases in gonadotropin and serum androgens, but severe IR persisted. CONCLUSION: Postnatal estrogen replacement and a marked decrease of endogenous androgens failed to improve IR and glucose tolerance. We propose that, in females, the increment of androgens and/or lack of estrogens during fetal life might alter the mechanism of fetal programming of insulin sensitivity.

Natural Occurrence of Secondary Bacterial Symbionts in Aphids from Tunisia, with a Focus on Genus Hyalopterus.

Aphids (Hemiptera: Aphididae) can harbor two types of bacterial symbionts. In addition to the obligate endosymbiont Buchnera aphidicola Munson, Baumann and Kinsey 1991 (Enterobacteriales: Enterobacteriaceae), several facultative symbiotic bacteria, called secondary (S) symbionts, have been identified among many important pest aphid species. To determine interpopulational diversity of S-symbionts, we carried out a survey in a total of 18 populations of six aphid species collected from six localities in Tunisia, by performing a diagnostic polymerase chain reaction analysis of partial 16S-23S rRNA operon sequences. While 61.7% of individuals contained only Buchnera, three S-symbionts were found at different frequencies. Arsenophonus sp. Gherna et al. 1991 (Enterobacteriales: Enterobacteriaceae) was found in all species under study except for Acyrtosiphon pisum (Harris 1776) (Aphidinae: Macrosiphini); Serratia symbiotica Moran et al. 2005 (Enterobacteriales: Enterobacteriaceae) was present in all analyzed individuals of A. pisum but only sporadically in Aphis spiraecola (Patch 1914) (Aphidinae: Aphidini) and Hyalopterus amygdali (Blanchard 1840) (Aphidinae: Aphidini), while Hamiltonella defensa Moran et al. 2005 (Enterobacteriales: Enterobacteriaceae) was found in all analyzed individuals of one population of Aphis gossypii (Glover 1877) (Aphidinae: Aphidini) and sporadically in two populations of Hyalopterus. The lysogenic bacteriophage APSE-1 (A. pisum secondary endosymbiont, type 1) was detected in the three populations infected with H. defensa. This bacteriophage has been associated with moderate protection against braconid parasitoids in pea aphids. The high prevalence of Arsenophonus sp. in our samples is in accordance with previous studies indicating that, among gammaproteobacteria, this genus is one of the most widespread insect facultative symbionts.

The genomic sequence of Exiguobacterium chiriqhucha str. N139 reveals a species that thrives in cold waters and extreme environmental conditions.

We report the genome sequence of Exiguobacterium chiriqhucha str. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of the Exiguobacterium genomes available suggest that our strain belongs to the same species as the previously reported E. pavilionensis str. RW-2 and Exiguobacterium str. GIC 31. We describe this species and propose the chiriqhucha name to group them. 'Chiri qhucha' in Quechua means 'cold lake', which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bp E. chiriqhucha str. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that confer E. chiriqhucha str. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals, high ultraviolet B radiation, scavenging for phosphorous and coping with high salinity. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina.

Identification and control of moulds responsible for black spot spoilage in dry-cured ham.

The aims of this work were to identify moulds responsible for black spot spoilage in the drying and cellar stages of dry-cured ham processing and evaluate the effectiveness of preventive actions for controlling this alteration. Four mould strains isolated from spoiled hams were identified by morphological characteristics and the ITS and ß-tubulin sequencing. Two of them were Cladosporium oxysporum, one was C. cladosporioides and the remaining one was C. herbarum. These spoiling strains reproduced the black spots on dry-cured ham-based media and ham slices. Additionally, the effect of water activity (aw) conditions reached throughout dry-cured ham ripening and the activity of the protective culture Penicillium chrysogenum CECT 20922 against the spoiling moulds were evaluated. In the dry-cured ham model system the growth of the Cladosporium strains was minimised when the aw approaches 0.84 or in P. chrysogenum CECT 20922 inoculated dry-cured ham slices. Therefore such combination could be used to avoid the black spot formation in dry-cured ham.