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Background: The benefits and harms associated with femoral artery cannulation over other sites of arterial cannulation for surgical repair of acute Stanford type A aortic dissection (TAAD) are not conclusively established., Methods: We evaluated the outcomes after surgery for TAAD using femoral artery cannulation, supra-aortic arterial cannulation (i.e., innominate/subclavian/axillary artery cannulation), and direct aortic cannulation., Results: 3751 (96.1%) patients were eligible for this analysis. In-hospital mortality using supra-aortic arterial cannulation was comparable to femoral artery cannulation (17.8% vs. 18.4%; adjusted OR 0.846, 95% CI 0.799-1.202). This finding was confirmed in 1028 propensity score-matched pairs of patients with supra-aortic arterial cannulation or femoral artery cannulation (17.5% vs. 17.0%, p = 0.770). In-hospital mortality after direct aortic cannulation was lower compared to femoral artery cannulation (14.0% vs. 18.4%, adjusted OR 0.703, 95% CI 0.529-0.934). Among 583 propensity score-matched pairs of patients, direct aortic cannulation was associated with lower rates of in-hospital mortality (13.4% vs. 19.6%, p = 0.004) compared to femoral artery cannulation. Switching of the primary site of arterial cannulation was associated with increased rate of in-hospital mortality (36.5% vs. 17.0%; adjusted OR 2.730, 95% CI 1.564-4.765). Ten-year mortality was similar in the study cohorts., Conclusions: In this study, the outcomes of surgery for TAAD using femoral arterial cannulation were comparable to those using supra-aortic arterial cannulation. However, femoral arterial cannulation was associated with higher in-hospital mortality than direct aortic cannulation., Trial Registration: ClinicalTrials.gov registration code: NCT04831073., (© 2024 International Society of Surgery/Société Internationale de Chirurgie (ISS/SIC).)

Aims: In this study we evaluated the impact of direct aortic cannulation versus innominate/subclavian/axillary artery cannulation on the outcome after surgery for type A aortic dissection., Methods: The outcomes of patients included in a multicenter European registry (ERTAAD) who underwent surgery for acute type A aortic dissection with direct aortic cannulation versus those with innominate/subclavian/axillary artery cannulation, i.e. supra-aortic arterial cannulation, were compared using propensity score matched analysis., Results: Out of 3902 consecutive patients included in the registry, 2478 (63.5%) patients were eligible for this analysis. Direct aortic cannulation was performed in 627 (25.3%) patients, while supra-aortic arterial cannulation in 1851 (74.7%) patients. Propensity score matching yielded 614 pairs of patients. Among them, patients who underwent surgery for TAAD with direct aortic cannulation had significantly decreased in-hospital mortality (12.7% vs. 18.1%, p = 0.009) compared to those who had supra-aortic arterial cannulation. Furthermore, direct aortic cannulation was associated with decreased postoperative rates of paraparesis/paraplegia (2.0 vs. 6.0%, p < 0.0001), mesenteric ischemia (1.8 vs. 5.1%, p = 0.002), sepsis (7.0 vs. 14.2%, p < 0.0001), heart failure (11.2 vs. 15.2%, p = 0.043), and major lower limb amputation (0 vs. 1.0%, p = 0.031). Direct aortic cannulation showed a trend toward decreased risk of postoperative dialysis (10.1 vs. 13.7%, p = 0.051)., Conclusions: This multicenter cohort study showed that direct aortic cannulation compared to supra-aortic arterial cannulation is associated with a significant reduction of the risk of in-hospital mortality after surgery for acute type A aortic dissection., Trial Registration: ClinicalTrials.gov Identifier: NCT04831073., (© 2023. The Author(s) under exclusive licence to Société Internationale de Chirurgie.)

Different strategies were tested to reduce biofilm formation of the model marine bacteria Cobetia marina and Marinobacter hydrocarbonoclasticus on cross-linked polydimethylsiloxane (PDMS) coated aluminum and cellulose acetate surfaces modified by addition of multi-walled carbon nanotubes (MWCNT) or exposure of the surfaces to bromine vapors in the presence and absence of UV irradiation. The three surface modifications explored led to important reductions in biofilm formation for the two marine bacteria, up to 30% in the case of exposure to Br 2 (g). Biofouling reduction could be correlated to surface properties in all cases through the introduction of a quantitative theoretical model based on an effective roughness parameter, Ra eff , that accounted for the different morphological changes observed. The model considers the possibility of bacterial inclusion into large surface wells, as observed by AFM in the case of Br 2 (g) + UV light treatment. In addition, a linear relationship was observed between biofouling reduction and the Ra eff effective roughness parameter., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The original version of this article contains error for some of the authors corrections were not included during correction stage especially for Table 1.

The production of black pigments in bacteria was discovered more than a century ago and related to tyrosine metabolism. However, their diverse biological roles and the control of melanin synthesis in different bacteria have only recently been investigated. The broad distribution of these pigments suggests that they have an important role in a variety of organisms. Melanins protect microorganisms from many environmental stress conditions, ranging from ultraviolet radiation and toxic heavy metals to oxidative stress. Melanins can also affect bacterial interactions with other organisms and are important in pathogenesis and survival in many environments. Bacteria produce several types of melanin through dedicated pathways or as a result of enzymatic imbalances in altered metabolic routes. The control of the melanin synthesis in bacteria involves metabolic and transcriptional regulation, but many aspects remain still largely unknown. The diverse properties of melanins have spurred a large number of applications, and recent efforts have been done to produce the pigment at biotechnologically relevant scales.

The environmental strain Aeromonas salmonicida subsp. pectinolytica 34mel T produces abundant melanin through the homogentisate pathway in several culture media, but unexpectedly not when grown in a medium containing glycerol. Using this observation as a starting point, this study investigated the underlying causes of the inhibition of melanin synthesis by glycerol, to shed light on factors that affect melanin production in this microorganism. The effect of different carbon sources on melanin formation was related to the degree of oxidation of their C atoms, as the more reduced substrates delayed melanization more than the more oxidized ones, although only glycerol completely abolished melanin production. Glyphosate, an inhibitor of aromatic amino acid synthesis, did not affect melanization, while bicyclopyrone, an inhibitor of 4-hydroxyphenylpyruvate dioxygenase (Hpd), the enzyme responsible for the synthesis of homogentisate, prevented melanin synthesis. These results showed that melanin production in 34mel T depends on the degradation of aromatic amino acids from the growth medium and not on de novo aromatic amino acid synthesis. The presence of glycerol changed the secreted protein profile, but none of the proteins affected could be directly connected with melanin synthesis or transport. Transcription analysis of hpd, encoding the key enzyme for melanin synthesis, showed a clear inhibition caused by glycerol. The results obtained in this work indicate that a significant decrease in the transcription of hpd, together with a more reduced intracellular state, would lead to the abolishment of melanin synthesis observed. The effect of glycerol on melanization can thus be attributed to a combination of metabolic and regulatory effects.

The aim of this work was to study phosphate (P) solubilization (and the processes involved in this event) by Talaromyces flavus (BAFC 3125) as a function of carbon and/or nitrogen sources. P solubilization was evaluated in NBRIP media supplemented with different carbon (glucose, sorbitol, sucrose, and fructose) and nitrogen (L-asparagine, urea, ammonium sulfate (AS), and ammonium nitrate (AN) combinations. The highest P solubilization was related to the highest organic acid production (especially gluconic acid) and pH drop for those treatments where glucose was present. Also P solubilization was higher when an inorganic nitrogen source was supplemented to the media when compared to an organic one. Although not being present an organic P source, phosphatase activity was observed. This shows that P mineralization and P solubilization can occur simultaneously, and that P mineralization is not induced by the enzyme substrate. The combination that showed highest P solubilization was for AN-glucose. The highest acid phosphatase activity was for AS-fructose, while for alkaline phosphatase were for AS-fructose and AN-fructose. Acid phosphatase activity was higher than alkaline. P solubilization and phosphatase activity (acid and alkaline) were influenced by the different carbon-nitrogen combinations. A better understanding of phosphate-solubilizing fungi could bring a better use of soil P.

Several biotechnological processes rely on the utilization of high-copy-number plasmids for heterologous gene expression, and understanding the interactions between plasmid DNA and bacterial hosts is highly relevant for bioprocess optimization. We assessed metabolic modifications and physiological changes exerted by expression of a plasmid-encoded alcohol-acetaldehyde dehydrogenase from Leuconostoc mesenteroides (adhE ( Lm )) in Escherichia coli redox mutants. Plasmid pET( Lm ), a pBluescript II KS(-)-derivative carrying adhE ( Lm ), was introduced in E. coli CT1061 [arcA creC(Con)]. This recombinant was able to attain a higher ethanol concentration in glycerol cultures compared to the parental strain. pBluescript II KS(-) was rapidly lost in 72-h bioreactor cultures (7.8 +/- 1.2% of plasmid-bearing cells), while pET( Lm ) was present in 92.4 +/- 7.2% of the cells. In E. coli CT1061 carrying pBluescript II KS(-) the plasmid copy number steadily diminished in bioreactor cultures to reach 334 +/- 45 copies per chromosome at 72 h, while pET( Lm ) was stably maintained, reaching 498 +/- 18 copies per chromosome at the end of the cultivation. Plasmid pETOmega( Lm ), bearing a defective copy of adhE ( Lm ) interrupted by cat, reached 293 +/- 62 copies per chromosome, implying a functional role of adhE ( Lm ) on plasmid maintenance. The intracellular NADH/NAD(+) content suggest that regeneration of oxidized co-factors by the heterologous bioreaction might play a relevant role in plasmid maintenance.

A Gram-negative, mobile, rod-shaped, non-spore-forming bacterium (strain 14-3(T)) was isolated from a temporary pond in Antarctica. On the basis of 16S rRNA gene sequence similarity, strain 14-3(T) was shown to belong to the genus Pseudomonas sensu stricto. Physiological and biochemical tests supported the phylogenetic affiliation. Strain 14-3(T) is closely related to Pseudomonas veronii DSM 11331(T), sharing 99.7% sequence similarity. DNA-DNA hybridization experiments between the two strains showed only moderate reassociation similarity (35.1%). Tests for arginine dihydrolase and nitrate reduction were positive, while those for denitrification, indol production, glucose acidification, urease, ss-galactosidase, esculin, caseine and gelatin hydrolysis were negative. Growth of this bacterium occurred in a range from 4 to 37 degrees C but not at 42 degrees C. It accumulated poly(3-hydroxybutyrate) when grown on sodium octanoate medium. Strain 14-3(T) therefore represents the type strain of a new species, for which the name Pseudomonas extremaustralis sp. nov. is proposed. The type strain 14-3(T) has been deposited as DSM 17835(T) and as CIP 109839(T).

Poly(3-hydroxybutyrate) (PHB) synthesis was analyzed under microaerobic conditions in a recombinant Escherichia coli arcA mutant using glycerol as the main carbon source. The effect of several additives was assessed in a semi-synthetic medium by the 'one-factor-at-a-time' technique. Casein amino acids (CAS) concentration was an important factor influencing both growth and PHB accumulation. Three factors exerting a statistically significant influence on PHB synthesis were selected by using a Plackett-Burman screening design [glycerol, CAS, and initial cell dry weight (CDW) concentrations] and then optimized through a Box-Wilson design. Under such optimized conditions (22.02 g l(-1) glycerol, 1.78 g l(-1) CAS, and 1.83 g l(-1) inoculum) microaerobic batch cultures gave rise to 8.37 g l(-1) CDW and 3.52 g l(-1) PHB in 48 h (PHB content of 42%) in a benchtop bioreactor. Further improvements in microaerobic PHB accumulation were obtained in fed-batch cultures, in which glycerol was added to maintain its concentration above 5 g l(-1). After 60 h, CDW and PHB concentration reached 21.17 and 10.81 g l(-1), respectively, which results in a PHB content of 51%. Microaerobic fed-batch cultures allowed a 2.57-fold increase in volumetric productivity when compared with batch cultures.

Pseudomonas sp. 14-3, a strain that accumulates large quantities of polyhydroxybutyrate (PHB) when grown on octanoate, was isolated from Antarctic environments. This isolate was characterized on the basis of phenotypic features and partial sequencing of its 16S ribosomal RNA gene. Pseudomonas sp. 14-3 showed increased tolerance to both thermal and oxidative stress compared with three other Pseudomonas species. Stress tolerance of Pseudomonas sp. 14-3 was analyzed in polyhydroxyalkanoate accumulating and non-accumulating conditions, and increased levels of stress resistance were observed when PHB was produced. Pseudomonas sp. 14-3 was isolated from Antarctic regions, a habitat normally exposed to extreme conditions. An association between high PHB accumulation and high stress resistance in bacteria adapted to extreme environments is suggested.

The molecular analysis of a genomic region of B. megaterium revealed the presence of a gene coding for the enzyme phosphotransbutyrylase (Ptb). The enzyme activity was measured throughout the different phases of growth in B. megaterium, and its activity was found to be maximal in the late exponential growth phase. The branched amino acids isoleucine and valine activated Ptb expression. PtbBm was capable of using butyryl-CoA and 2-methyl-propionyl CoA as substrates. ActBm, a final sigma54 regulator from B. megaterium whose gene is situated upstream from the ptb gene, activated its expression.

A Bacillus megaterium genomic fragment, which encoded an activator homologous to sigma 54 regulators and which was capable of activating Escherichia coli ato genes in trans, was detected in a gene library of B. megaterium screened for beta-ketothiolase activity. The fragment presented only one complete open reading frame (ORF1), which encoded a protein of 398 amino acids. The recombinant plasmid complemented mutations in the Escherichia coli atoC regulatory gene. The constitutive expression of the E. coli ato operon mediated by ORF1 could be useful for the synthesis of polyhydroxyalkanoates with different flexibility properties by recombinant E. coli strains.