Halomonas sinaiensis sp. nov., a novel halophilic bacterium isolated from a salt lake inside Ras Muhammad Park, Egypt

An alkalitolerant and halotolerant bacterium, designated strain Sharm was isolated from a salt lake inside Ras Muhammad. The morphological, physiological and genetic characteristics were compared with those of related species of the genus Halomonas. The isolate grew optimally at pH 7.0, 5–15% NaCl at 35°C. The cells were Gram-negative rods, facultative anaerobes. They accumulated glycine-betaine, as a major osmolyte, and ectoine and glutamate as minor components. The strain Sharm^T biosynthetised α-glucosidase. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and a novel phosphoglycolipid as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and, nC16:0 and C19:0 with cyclopropane were the main cellular fatty acids, accounting for 87.3% of total fatty acids. The G + C content of the genomic DNA was 64.7 mol %. The 16S rRNA sequence analysis indicated that strain Sharm was a member of the genus Halomonas. The closest relatives of the strain Sharm were Halomonas elongata and Halomonas eurihalina. However, DNA–DNA hybridisation results clearly indicated that strain Sham was a distinct species of Halomonas. On the basis of the evidence, we propose to assign strain Sharm as a new species of the genus Halomonas, H. sinaiensis sp. nov, with strain Sharm^T as the type strain (DSM 18067^T; ATCC BAA-1308^T). The EMBL accession number for the 16S rRNA sequence of Halomonas sinaiensis strain Sharm^T is AM238662.     

Structural elucidation of a novel phosphoglycolipid isolated from six species of Halomonas

The structure of a new phosphoglycolipid from the halophilic Gram-negative bacteria Halomonas elongata ATCC 33173(T), Halomonas eurihalina ATCC 49336(T), Halomonas almeriensis CECT 7050(T), strain Sharm (AM238662), Halomonas halophila DSM 4770(T), and Halomonas salina ATCC 49509(T) was elucidated by NMR and mass spectroscopy studies. In all of the species examined, the polar lipid composition consisted of 1,2-diacylglycero-3-phosphorylethanolamine, 1,2-diacylglycero-3-phosphoryl-glycerol, bisphosphatidyl glycerol, and the new phosphoglycolipid PGL1. The structure of PGL1 was established to be (2-(alpha-D-glucopyranosyloxy)-3-hydroxy-propyl)-phosphatidyl diacylglycerol. C16:0;C18:1 and C16:0;C19:cyclopropane are the most abundant acyl chains linked to the phosphatidylglycerol moiety of each isolated PGL1. All of the species presenting the lipid PGL1 belong to Halomonas rRNA group 1, suggesting that the new phosphoglycolipid could be a chemotaxonomic marker of this phylogenetic group.     

Socio-Economic and Clinical Factors as Predictors of Disease Evolution and Acute Events in COPD Patients

Background

Socio-economic, cultural and environmental factors are becoming increasingly important determinants of chronic obstructive pulmonary disease (COPD). We conducted a study to investigate socio-demographic, lifestyle and clinical factors, and to assess their role as predictors of acute events (mortality or hospitalization for respiratory causes) in a group of COPD patients.

Methods

Subjects were recruited among outpatients who were undertaking respiratory function tests at the Pneumology Unit of the Sant’Orsola-Malpighi Hospital, Bologna. Patients were classified according to the GOLD Guidelines.

Results

229 patients with COPD were included in the study, 44 with Mild, 68 Moderate, 52 Severe and 65 Very Severe COPD (GOLD stage). Significant differences among COPD stage, in terms of smoking status and fragility index, were detected. COPD stage significantly affected the values of all clinical tests (spirometry and ABG analysis). Kaplan-Meier estimates showed a significant difference between survival curves by COPD stage with lower event-free probability in very severe COPD stage. Significant risk factors for acute events were: underweight (HR = 4.08; 95% CI 1.01–16.54), having two or more comorbidities (HR = 4.71; 95% CI 2.52–8.83), belonging to moderate (HR = 3.50; 95% CI 1.01–12.18) or very severe COPD stage (HR = 8.23; 95% CI 2.35–28.85).

Conclusions

Our findings indicate that fragility is associated with COPD stage and that comorbidities and the low body mass index are predictors of mortality or hospitalization. Besides spirometric analyses, FeNO measure and comorbidities, body mass index could also be considered in the management and monitoring of COPD patients.     

When Chocolate Seeking Becomes Compulsion: Gene-Environment Interplay

Background

Eating disorders appear to be caused by a complex interaction between environmental and genetic factors, and compulsive eating in response to adverse circumstances characterizes many eating disorders.

Materials and Methods

We compared compulsion-like eating in the form of conditioned suppression of palatable food-seeking in adverse situations in stressed C57BL/6J and DBA/2J mice, two well-characterized inbred strains, to determine the influence of gene-environment interplay on this behavioral phenotype. Moreover, we tested the hypothesis that low accumbal D2 receptor (R) availability is a genetic risk factor of food compulsion-like behavior and that environmental conditions that induce compulsive eating alter D2R expression in the striatum. To this end, we measured D1R and D2R expression in the striatum and D1R, D2R and α1R levels in the medial prefrontal cortex, respectively, by western blot.

Results

Exposure to environmental conditions induces compulsion-like eating behavior, depending on genetic background. This behavioral pattern is linked to decreased availability of accumbal D2R. Moreover, exposure to certain environmental conditions upregulates D2R and downregulates α1R in the striatum and medial prefrontal cortex, respectively, of compulsive animals. These findings confirm the function of gene-environment interplay in the manifestation of compulsive eating and support the hypothesis that low accumbal D2R availability is a “constitutive” genetic risk factor for compulsion-like eating behavior. Finally, D2R upregulation and α1R downregulation in the striatum and medial prefrontal cortex, respectively, are potential neuroadaptive responses that parallel the shift from motivated to compulsive eating.     

Growth, gas exchange and ion content in Olea europaea plants during salinity stress and subsequent relief

Olive ( Olea europaea L. cv. Frantoio) plants grown hydroponically in a glasshouse were supplied with half-strength Hoagland solutions containing 0, 50, 100, and 200 m M NaCl for 4 weeks and subsequently supplied with the standard solution without NaCl to relieve salinity stress. Two complete stress-relief cycles were repeated on the same plant material during one growing season. Growth was inhibited at all salt levels, but most growth parameters of plants treated with 50 or 100 m M NaCl returned to control levels after 4 weeks of relief. More severely stressed plants (200 m M NaCl) recovered to only 60% of the growth of the controls after 4 weeks. During relief, plants treated with 50 and 100 m M NaCl had net photosynthetic rates and stomatal conductances higher than the controls. Increasing the NaCl concentration of the external solution from 0 to 200 m M decreased both leaf pre-dawn water potential (from -0.3 to -1.0 MPa) and osmotic potential (from -2.1 to -2.7 MPa). The sodium concentration in the leaves of plants treated with 200 m M NaCl reached maximum levels of 211 and 388 m M (expressed on a tissue water basis) at the end of the first salinity and relief periods, respectively. Leaf chloride concentrations were 359 and 223 m M at the same sampling dates. These data indicate that the inhibitory effects of salinization on growth and gas exchange of the salt-tolerant olive cv. Frantoio can be readily reversed when salinity is relieved, despite the marked accumulation of potentially toxic ions (Na⁺. Cl) in the leaf.     

Bacterial copper- and zinc-cofactored superoxide dismutase contributes to the pathogenesis of systemic salmonellosis

Copper/zinc-cofactored superoxide dismutase ([Cu,Zn]-SOD) has been found in the periplasm of many bacterial species but its biological function is unknown. Here we report the cloning and characterization of sodC , encoding [Cu,Zn]-SOD, from Salmonella typhimurium . The predicted protein sequence shows only 58% identity to Escherichia coli SodC, and from this its chromosomal location and its immediate proximity to a phage gene, sodC , in Salmonella is speculated to have been acquired by bacteriophage-mediated horizontal transfer from an unknown donor. A sodC mutant of S . typhimurium was unimpaired on aerobic growth in rich medium but showed enhanced sensitivity in vitro to the microbicidal action of superoxide. S . typhimurium , S . choleraesuis and S . dublin sodC mutants showed reduced lethality in a mouse model of oral infection and persisted in significantly lower numbers in livers and spleens after intraperitoneal infection, suggesting that [Cu,Zn]-SOD plays a role in pathogenicity, protecting Salmonella against oxygen radical-mediated host defences. There was, however, no observable difference compared with wild type in the interaction of sodC mutants with porcine pleural, mouse peritoneal or J774 macrophages in vitro , perhaps reflecting the hierarchical capacity of different macrophage lines to kill Salmonella , the most efficient overwhelming the proposed protective effect of periplasmic SOD.     

Energy transduction in photosynthetic bacteria. XI. Further resolution of cytochromes of b type and the nature of the CO-sensitive oxidase present in the respiratory chain of Rhodopseudomonas capsulata

1. In membranes prepared from dark grown cells of Rhodopseudomonas capsulata, five cytochromes of b type (E′₀ at pH 7.0 +413±5, +270±5, +148±5, +56±5 and −32±5 mV) can be detected by redox titrations at different pH values. The midpoint potentials of only three of these cytochromes (b₁₄₈, b₅₆, and b₋₃₂) vary as a function of pH with a slope of 30 mV per pH unit.

2. In the presence of a Co/N₂ mixture, the apparent E′₀ of cytochrome b₂₇₀ shifts markedly towards higher potentials (+355 mV); a similar but less pronounced shift is apparent also for cytochrome b₁₅₀. The effect of CO on the midpoint potential of cytochrome b₂₇₀ is absent in the respiration deficient mutant M6 which possesses a specific lesion in the CO-sensitive segment of the branched respiratory chain present in the wild type strain.

3. Preparations of spheroplasts with lysozyme digestion lead to the release of a large amount of cytochrome c₂ and of virtually all cytochrome cc′. These preparations show a respiratory chain impaired in the electron pathway sensitive to low KCN concentration, in agreement with the proposed role of cytochrome c₂ in this branch; on the contrary, the activity of the CO-sensitive branch remains unaffected, indicating that neither cytochrome c₂ nor the CO-binding cytochrome cc′ are involved in this pathway.

4. Membranes prepared from spheroplasts still possess a CO-binding pigment characterized by maxima at 420.5, 543 and 574 nm and minima at 431, 560 nm in CO-difference spectra and with an band at 562.5 nm in reduced minus oxidized difference spectra. This membrane-bound cytochrome, which is coincident with cytochrome b₂₇₀, can be classified as a typical cytochrome “o” and considered the alternative CO-sensitive oxidase.     

Molecular identification of ‘Candidatus Phytoplasma palmicola’ associated with coconut lethal yellowing in Equatorial Guinea

During the past two decades, a high mortality of coconut palms was observed in the coastal areas of Equatorial Guinea. Reportedly, the palm population has been reduced by 60%–70%, and coconut production has decreased accordingly. To identify the cause of the mortality, a survey was carried out in April 2021 in various localities of the coconut belt. Molecular analyses carried out on 16S rRNA and secA genes detected phytoplasma presence in the majority of the samples. Sequencing and BLAST search of the 16S rRNA gene sequences showed >99% identity of the detected phytoplasmas to ‘Candidatus Phytoplasma palmicola’. The RFLP analyses of 16S ribosomal gene using Tru1I and TaqI enzymes led to assign these phytoplasmas to subgroup 16SrXXII-A. In all samples that tested positive, including one from a hybrid coconut palm and two from oil palm the same phytoplasma was identified. The phylogenetic analyses of 16S rRNA and secA genes confirmed respectively 99.98%–100% and 97.94%–100% identity to ‘Ca. P. palmicola’. RFLP analyses using MboII enzyme on the secA gene amplicon differentiated the phytoplasma found in Equatorial Guinea from those present in Ghana and Ivory Coast. The Equatorial Guinean phytoplasma strain resulted to be identical to the strains from Mozambique, confirming the presence of a geographic differentiation among phytoplasma strains in the coastal areas of Western and Central Africa. The identified phytoplasma is different from the ‘Ca. P. palmicola’ strains found in Ghana and Ivory Coast and represents the first identification a 16SrXXII-A strain in Equatorial Guinea and in Central Africa. Strict monitoring and surveillance procedures for early detection of the pathogen are strongly recommended to reduce its impact and further spread in the country and permit the recovery of coconut plantations.