Prokaryotic community profiles at different operational stages of a Greek solar saltern

A combination of culture-dependent and independent approaches was employed to identify the microbial community structure in a Greek solar saltern. A total of 219 and 132 isolates belonging, respectively, to Bacteria and Archaea, were recovered. All bacterial isolates were phylogenetically related to 43 members of Actinobacteria, Firmicutes and gamma-Proteobacteria. The archaeal isolates were placed within the Halobacteriaceae. At least four groups of isolates represented novel species among the Bacteria. High bacterial diversity, consisting of 417 subfamilies, was revealed using a high-density oligonucleotide microarray (PhyloChip). At the four stages of saltern operation analyzed, the archaeal community consisted of both Crenarchaeota and Euryarchaeota, except for the sediment where Crenarchaeota were not detected. The bacterial community in sediment consisted mainly of gamma-Proteobacteria and Actinobacteria, while, in hypersaline water, it was restricted to a few representatives of Bacteria. Members of alpha-Proteobacteria were the main constituents in saturated brine and crude salt, followed by gamma-Proteobacteria, Actinobacteria and Firmicutes. A large Bacteroidetes and Verrucomicrobia diversity was identified in saturated brine, while delta-Proteobacteria and Cloroflexi were abundant in crude salt. Significant changes in the microbial community structure were detected during a short time period, denoting a rapidly adaptive dynamic ecosystem and viable diversity. Prokaryotic members reported for the first time in solar salterns were identified.     

Biodiversity of prokaryotic communities in sediments of different sub-basins of the Venice lagoon

Microbial community structure and diversity in the wide and shallow Venice lagoon were assessed, prior to construction of mobile dams, at nine stations representative of four different sub-basins previously selected on the basis of international guidelines for sediment quality. The sediments were mainly anoxic and were colonized by microbial communities the species richness of which was quantitatively correlated with total elemental sulfur and acid-volatile sulfide. Automated ribosomal intergenic spacer analysis clustered the stations into three groups. One station for each group was hence analyzed in detail for bacterial and archaeal diversity by screening of 16S rRNA gene clone libraries. The dominance of Gammaproteobacteria clones (84% with a high proportion of Vibrionaceae, indicator of urban pollution) determined significant divergence of the station adjacent to industrial and metropolitan areas. Bacteroidetes were widespread, especially where prairies of aquatic plants are located. The other two analyzed stations were dominated by bacterial taxa implicated in the sulfur cycle: the anoxygenic photosynthetic Chromatiales, sulfate- and sulfur-reducing Desulfobacterales and Desulfuromonadales, and members of the Alpha- and Epsilonproteobacteria.     

Taxonomic and functional prokaryote diversity in mildly arsenic-contaminated sediments

Arsenic-resistant prokaryote diversity is far from being exhaustively explored. In this study, the arsenic-adapted prokaryotic community present in a moderately arsenic-contaminated site near Sainte-Marie-aux-Mines (France) was characterized, using metaproteomic and 16S rRNA-encoding gene amplification. High prokaryotic diversity was observed, with a majority of Proteobacteria, Acidobacteria and Bacteroidetes, and a large archaeal community comprising Euryarchaeaota and Thaumarchaeota. Metaproteomic analysis revealed that Proteobacteria, Planctomycetes and Cyanobacteria are among the active bacteria in this ecosystem. Taken together, these results highlight the unsuspected high diversity of the arsenic-adapted prokaryotic community, with some phyla never having been described in highly arsenic-exposed sites.     

The extremely halophilic archaeon Halobacterium salinarum ETD5 from the solar saltern of Sfax (Tunisia) produces multiple halocins

The extremely halophilic archaeon Halobacterium salinarum strain ETD5 was previously isolated from the solar saltern of Sfax (Tunisia) and shown to encode and express halocin S8. The Hbt. salinarum ETD5 culture supernatant was shown here to exhibit high antimicrobial activity against several halophilic archaea and bacteria of different genera, showing a cross-domain inhibition. The antimicrobial activity was destroyed by proteases, thus pointing to halocins. A bioguided purification procedure was applied using two chromatography steps and antimicrobial assays directed against Halorubrum chaoviator ETR14. In-gel screening assay showed the presence of two antimicrobial bands of approximately 8 and 14 kDa, for which characterization was investigated by N-terminal sequencing and mass spectrometry. The full-length form of halocin S8 that contains 81 amino acids and differs from the 36 amino acid short-length halocin S8 previously described from an uncharacterized haloarchaeon S8a, was identified in the 8 kDa halocin band. A novel halocin that we termed halocin S14 was found in the 14 kDa band. It exhibits amino acid sequence identities with the N-terminally truncated region of the archaeal Mn-superoxide dismutase. These results show that Hbt. salinarum ETD5 produces multiple halocins, a feature that had not been described until now in the domain Archaea.     

RT-PCR-RFLP for genetic diversity analysis of Tunisian Grapevine fanleaf virus isolates in their natural host plants

Genetic diversity was characterized in 20 isolates of Grapevine fanleaf virus (GFLV) recovered from naturally infected grapevine plants (Vitis vinifera) in the North of Tunisia. Viral RNAs were isolated by oligoprobe capture, and a 605 bp fragment containing a part of the viral coat protein gene was amplified by RT-PCR. Sequence variation among isolates was characterized by restriction fragment length polymorphism (RFLP) analysis and confirmed by sequencing. The GFLV infections are found as a complex mixture of closely related genomes. In further studies, RFLP analyses of virus isolates using AluI showed that GFLV populations in Tunisian vineyards consist of two restrictotypes corresponding to distinct sub-populations Sp1 and Sp2. The relative field distribution of these sub-populations showed that Sp2 was more abundant. Individual genomes were recovered by cloning the RT-PCR products. The sequences were found to vary from each other by as much as 11%. Cloning from mixed infections showed that Sp2 are also predominant.     

Prevalence and genetic diversity of norovirus infection in Tunisian children (2007–2010)

Viral gastroenteritis can be a life‐threatening disease in infants and young children, especially in developing countries. The aim of this study was to continue the epidemiological surveillance of norovirus (NoV) infections in Tunisian children suffering from acute gastroenteritis. Surveillance was initiated in January 2003, to monitor potential variations in strains over time, in terms of frequency and diversity of NoV genotypes, and more particularly the potential emergence of new GII.4 variants following the 2004 Hunter variant. From April 2007 to April 2010, a total of 407 stool specimens were collected from sporadic cases (238 inpatients and 169 outpatients). Furthermore, 28 stool samples were collected from children involved in 3 gastroenteritis outbreaks. Stool specimens were screened for NoV genogroup I (GI) and II (GII) by RT‐PCR. NoV strains were genotyped, and variants identified, based on sequence and phylogenetic analyses of the polymerase and capsid genes. NoVs were detected in 38 sporadic cases (9.3%) and 21 epidemic cases (75%). Great diversity was observed throughout the period, with seven distinct NoV genotypes characterized in sporadic cases, and three in outbreaks. GIIb/II.3 and GII.4 were predominant globally, with fluctuations of their prevalence over time. Interestingly, the Hunter variant, which was the unique GII.4 variant observed from 2003 to April 2007 in the region of Monastir, was replaced by the 2006b variant. NoV is an important enteropathogen responsible for viral gastroenteritis among infants and children in Tunisia, and the infecting strains between 2007 and 2010 were different from those in previous years. J. Med. Virol. 85: 1100–1110, 2013. © 2013 Wiley Periodicals, Inc.     

Novel insights into macrophage diversity in rheumatoid arthritis synovium

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease affecting joints and causing progressive damage and disability. Macrophages are of critical importance in the initiation and perpetuation of synovitis in RA, they can function as antigen presenting cells leading to T-cell dependent B-cell activation, assume a variety of inflammatory cell states with the production of destructive cytokines, but also contribute to tissue homeostasis/repair. The recent development of high-throughput technologies, including bulk and single cells RNA-sequencing, has broadened our understanding of synovial cell diversity, and opened novel perspectives to the discovery of new potential therapeutic targets in RA. In this review, we will focus on the relationship between the synovial macrophage infiltration and clinical disease severity and response to treatment. We will then provide a state-of-the-art picture of the biological roles of synovial macrophages and distinct macrophage subsets described in RA. Finally, we will review the effects of approved conventional and biologic drugs on the synovial macrophage component and highlight the therapeutic potential of future strategies to re-program macrophage phenotypes in RA.     

Comorbidity in the Tunisian population

Genetic diseases in the Tunisian population represent a real problem of public health as their spectrum encompasses more than 400 disorders. Their frequency and distribution in the country have been influenced by demographic, economic and social features especially consanguinity. In this article, we report on genetic disease association referred to as comorbidity and discuss factors influencing their expressivity. Seventy‐five disease associations have been reported among Tunisian families. This comorbidity could be individual or familial. In 39 comorbid associations, consanguinity was noted. Twenty‐one founder and 11 private mutations are the cause of 34 primary diseases and 13 of associated diseases. As the information dealing with this phenomenon is fragmented, we proposed to centralize it in this report in order to draw both clinicians' and researcher's attention on the occurrence of such disease associations in inbred populations as it makes genetic counseling and prenatal diagnosis challenging even when mutations are known.     

Novel missense mutations of TMPRSS3 in two consanguineous Tunisian families with non‐syndromic autosomal recessive deafness

Recently the TMPRSS3 gene, which encodes a transmembrane serine protease, was found to be responsible for two non‐syndromic recessive deafness loci located on human chromosome 21q22.3, DFNB8 and DFNB10. We found evidence for linkage to the DFNB8/10 locus in two unrelated consanguineous Tunisian families segregating congenital autosomal recessive sensorineural deafness. The audiometric tests showed a loss of hearing greater than 70 dB, in all affected individuals of both families. Mutation screening of TMPRSS3 revealed two novel missense mutations, W251C and P404L, altering highly conserved amino acids of the serine protease domain. Both mutations were not found in 200 control Tunisian chromosomes. The detection of naturally‐occurring TMPRSS3 missense mutations in deafness families identifies functionally important amino acids. Comparative protein modeling of the TMPRSS3 protease domain predicted that W251C might lead to a structural rearrangement affecting the active site H257 and that P404L might alter the geometry of the active site loop and therefore affect the serine protease activity. Hum Mutat 18:101–108, 2001. © 2001 Wiley‐Liss, Inc.     

Novel missense mutations of TMPRSS3 in two consanguineous Tunisian families with non‐syndromic autosomal recessive deafness

Regarding this article: The corresponding author of this article regrets that the last name of one of the co‐authors was misspelled. Dr. M’hamed GRATI was incorrectly listed as “GRATRI” in the author list. Since it is too late for the publisher to correct this error in the actual journal article, we wish to clarify the matter for the record, for indexing and abstracting purposes.     

Spectrum of Autoantibodies in Tunisian Psychiatric Inpatients

One hundred and three psychiatric inpatients (74 men) were assessed for a wide spectrum of autoantibodies including antinuclear, antismooth muscle, antimitochondrial, antiDNA, anti-phospholipid, anti-cardiolipin IgG and IgM, antikeratin, rheumatoid factor, antithyroperoxydase, antigliadin IgA and IgG, antitransgutaminase, and antiendomysium antibodies. Four groups of patients were considered separately, including 47 with schizophrenia, 23 with schizoaffective disorder, 16 with bipolar disorder and 17 patients with other different psychiatric diagnosis. Forty one healthy, age- and sex-matched blood donors were used as a control group. There were no significant difference in the prevalence of the different autoantibodies between patients (N = 103) and controls except for antigliadin IgG (30.1 vs 9.8 respectively, p = 0.01). Presence of autoantibodies was influenced by age but not by sex or treatment. As for diagnosis categories, patients with bipolar disorder presented significantly more autoantibodies than the three other categories and controls. These results point out a possible autoimmune activation in at least a subgroup of psychiatric patients especially amongst those suffering from bipolar disorder.     

Spectrum of autoantibodies in Tunisian psychiatric inpatients

One hundred and three psychiatric inpatients (74 men) were assessed for a wide spectrum of autoantibodies including antinuclear, antismooth muscle, antimitochondrial, antiDNA, anti-phospholipid, anti-cardiolipin IgG and IgM, antikeratin, rheumatoid factor, antithyroperoxydase, antigliadin IgA and IgG, antitransgutaminase, and antiendomysium antibodies. Four groups of patients were considered separately, including 47 with schizophrenia, 23 with schizoaffective disorder, 16 with bipolar disorder and 17 patients with other different psychiatric diagnosis. Forty one healthy, age- and sex-matched blood donors were used as a control group. There were no significant difference in the prevalence of the different autoantibodies between patients (N = 103) and controls except for antigliadin IgG (30.1 vs 9.8 respectively, p = 0.01). Presence of autoantibodies was influenced by age but not by sex or treatment. As for diagnosis categories, patients with bipolar disorder presented significantly more autoantibodies than the three other categories and controls. These results point out a possible autoimmune activation in at least a subgroup of psychiatric patients especially amongst those suffering from bipolar disorder.     

Shifts in phylogenetic diversity of archaeal communities in mangrove sediments at different sites and depths in southeastern Brazil

This study focused on the structure and composition of archaeal communities in sediments of tropical mangroves in order to obtain sufficient insight into two Brazilian sites from different locations (one pristine and another located in an urban area) and at different depth levels from the surface. Terminal restriction fragment length polymorphism (T-RFLP) of PCR-amplified 16S rRNA gene fragments was used to scan the archaeal community structure, and 16S rRNA gene clone libraries were used to determine the community composition. Redundancy analysis of T-RFLP patterns revealed differences in archaeal community structure according to location, depth and soil attributes. Parameters such as pH, organic matter, potassium and magnesium presented significant correlation with general community structure. Furthermore, phylogenetic analysis revealed a community composition distributed differently according to depth where, in shallow samples, 74.3% of sequences were affiliated with Euryarchaeota and 25.7% were shared between Crenarchaeota and Thaumarchaeota, while for the deeper samples, 24.3% of the sequences were affiliated with Euryarchaeota and 75.7% with Crenarchaeota and Thaumarchaeota. Archaeal diversity measurements based on 16S rRNA gene clone libraries decreased with increasing depth and there was a greater difference between depths (<18% of sequences shared) than sites (>25% of sequences shared). Taken together, our findings indicate that mangrove ecosystems support a diverse archaeal community; it might possibly be involved in nutrient cycles and are affected by sediment properties, depth and distinct locations.     

Metabolic syndrome in Tunisian bipolar I patients

Background

The metabolic syndrome is a growing global public health problem which is frequently associated with psychiatric illness.

Objectives

To evaluate the prevalence of metabolic syndrome and to study its profile in Tunisian bipolar I patients.

Methods

Our study included 130 patients with bipolar I disorder diagnosed according to the DSM-IV and assessed for metabolic syndrome according to the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III modified criteria. The mean age was 37.9 ±12.1 years, 45 were women (mean age 37.5±13.4 years) and 85 were men (mean age 38.1 ± 11.4 years).

Results

The prevalence of metabolic syndrome was 26.1%.The highest prevalence of this syndrome was obtained by association between obesity, low c-HDL and hypertriglyceridemia (44.1%). In the total sample, 59.2% met the criteria for low c-HDL, 53.1% for hypertriglyceridemia, 33.8% for obesity, 16.1% for high fasting glucose and 5.4% for hypertension. Gender, age, illness episode and treatment were not significantly associated with metabolic syndrome, while patients under lithium had higher prevalence of metabolic syndrome than those under valproic acid, carbamazepine or antipsychotics. Patients with metabolic syndrome had significant higher levels of HOMA-IR and uric acid than metabolic syndrome free patients (p< 0.001).

Conclusions

Bipolar patients have high prevalence of metabolic syndrome which is associated with insulin resistance and an increase of uric acid values that raise the risk of cardiovascular disease.     

NA antigen frequencies in the Tunisian population

The biallelic NA antigen system is of special interest as the NA antigens are frequent targets of neutrophil antibodies, causing alloimmune neonatal neutropenia, blood transfusion reactions, and chronic benign autoimmune neutropenia in infancy. Neutrophils isolated from the peripheral blood of 119 unrelated individuals at the National Blood Center were phenotyped for NA1 and NA2 using a granulocyte immunofluorescence assay. A subsequent analysis of the phenotyping study showed that the NA1 and NA2 antigen frequencies were 0.529 and 0.865 respectively, and that the estimated NA1 and NA2 gene frequencies were 0.313 and 0.632 respectively. In conclusion, it was determined that the Tunisian population is of Caucasian origin. However, to validate this finding, further investigations are necessary.     

Novel KChIP2 isoforms increase functional diversity of transient outward potassium currents

Kv4.3 channels conduct transient outward K⁺ currents in the human heart and brain where they mediate the early phase of action potential repolarization. KChIP2 proteins are members of a new class of calcium sensors that modulate the surface expression and biophysical properties of Kv4 K⁺ channels. Here we describe three novel isoforms of KChIP2 with an alternatively spliced C-terminus (KChIP2e, KChIP2f) or N-terminus (KChIP2g). KChIP2e and KChIP2f are expressed in the human atrium, whereas KChIP2g is predominantly expressed in the brain. The KChIP2 isoforms were coexpressed with Kv4.3 channels in Xenopus oocytes and currents recorded with two-microelectrode voltage-clamp techniques. KChIP2e caused a reduction in current amplitude, an acceleration of inactivation and a slowing of the recovery from inactivation of Kv4.3 currents. KChIP2f increased the current amplitude and slowed the rate of inactivation, but did not alter the recovery from inactivation or the voltage of half-maximal inactivation of Kv4.3 channels. KChIP2g increased current amplitudes, slowed the rate of inactivation and shifted the voltage of half-maximal inactivation to more negative potentials. The biophysical changes induced by these alternatively spliced KChIP2 proteins differ markedly from previously described KChIP2 proteins and would be expected to increase the diversity of native transient outward K⁺ currents.