Short-term effects of a 3-week interval training program on heart rate variability in chronic heart failure. A randomised controlled trial.

BACKGROUND: Exaggerated sympathetic nervous system activity associated with low heart rate variability (HRV) is considered to trigger cardiac arrhythmias and sudden death. Regular exercise training is efficient to improve autonomic balance. OBJECTIVE: We aimed to verify the superiority of high-intensity interval training (HIIT) to enhance HRV, cardiorespiratory fitness and cardiac function as compared with moderate intensity continuous training (MICT) in a short, intense cardiac rehabilitation program. METHODS: This was a prospective, monocentric, evaluator-blinded, randomised (1:1) study with a parallel two-group design. Overall, 31 individuals with voluntary chronic heart failure (CHF) (left ventricular ejection fraction [LVEF]<45%) were allocated to MICT (n=15) or HIIT (n=16) for a short rehabilitation program (mean [SD] 27 [4] days). Participants underwent 24-hr electrocardiography, echocardiography and a cardiopulmonary exercise test at entry and at the end of the study. RESULTS: High-frequency power in normalized units (HFnu%) measured as HRV increased with HIIT (from 21.2% to 26.4%, P<0.001) but remained unchanged with MICT (from 23.1% to 21.9%, P=0.444, with a significant intergroup difference, P=0.003). Resting heart rate (24-hr Holter electrocardiography) decreased significantly for both groups (from 68.2 to 64.6 bpm and 66.0 to 63.5 bpm for MICT and HIIT, respectively, with no intergroup difference, P=0.578). The 2 groups did not differ in premature ventricular contractions. Improvement in peak oxygen uptake was greater with HIIT than MICT (+21% vs. +5%, P=0.009). LVEF improved with only HIIT (from 36.2% to 39.5%, P=0.034). CONCLUSIONS: In this short rehabilitation program, HIIT was significantly superior to the classical MICT program for enhancing parasympathetic tone and peak oxygen uptake. CLINICALTRIALS. GOV IDENTIFIER: NCT03603743.

Effects of short-term exercise and exercise training on cognitive function among patients with cardiac disease.

PURPOSE: A number of studies have investigated the effect of physical activity on cognitive performance in healthy subjects although no consensus in results has been established. In patients with cardiac disease that has been associated with cognitive impairment, research regarding improvement in cognition function assumes a clinical interest. We assessed the effect of both acute exercise and aerobic training on cognitive function in patients with coronary artery disease and heart failure who participated in cardiac rehabilitation (CR). METHODS: Twenty-four men (mean age = 51.6 +/- 6.5 years) completed 2 experimental sessions, before (S1) and after exercise training (S2). During each session, participants underwent cognitive evaluations at rest and during exercise on a cycloergometer at 30% of maximal power. Two types of evaluations were used, an exclusively cognitive test (COG, such as arithmetic test, memory test) and a tracking task (TRAC) including motor precision. RESULTS: At S1, no significant difference appeared between rest and acute exercise for COG score (31.5 +/- 9.5 vs 32.2 +/- 10.5; ns). In contrast, acute exercise significantly improved TRAC performance (149 +/- 54 vs 140 +/- 44; P < .05). At S2, COG score improved with exercise (35.5 +/- 10.6 vs 40 +/- 10.8; P < or = .001) but TRAC score remained unchanged (138 +/- 50 vs 134 +/- 42; ns). Concerning the impact of exercise (Delta%), a significant difference was observed for COG (0.03 [-0.03 to 0.11] vs 0.14 [-0.01 to 0.24]; P < .05), before and after training, respectively, but not for TRAC. CONCLUSIONS: Limited data are available concerning the effect of acute exercise and exercise training on cognitive function in patients with cardiac disease. This study provides evidence for the importance of CR in improving cognitive function.

Petrobacter succinatimandens gen. nov., sp. nov., a moderately thermophilic, nitrate-reducing bacterium isolated from an Australian oil well.

A novel Gram-negative, aerobic and moderately thermophilic bacterium, strain 4BON(T), was isolated from a non-water-flooded Australian terrestrial oil reservoir. Cells were non-spore-forming straight rods, which were motile by means of a polar flagellum. The optimum growth conditions were 55 degrees C, pH 6.9 and 0.5 % NaCl. Strain 4BON(T) was oxidase- and catalase-positive; it grew on fumarate, pyruvate, succinate, formate, ethanol and yeast extract in the presence of oxygen or nitrate as terminal electron acceptor. Nitrate was reduced to nitrous oxide. The DNA G+C content of the strain was 58.6 mol%. The closest phylogenetic relative of strain 4BON(T) was Hydrogenophilus thermoluteolus (similarity of 91.8 %), of the beta-Proteobacteria. As strain 4BON(T) is physiologically and phylogenetically different from H. thermoluteolus, it is proposed that it be assigned to a novel species of a novel genus, Petrobacter succinatimandens gen. nov., sp. nov. The type strain is 4BON(T) (=DSM 15512(T)=CIP 107790(T)).

Isolation from oil reservoirs of novel thermophilic anaerobes phylogenetically related to Thermoanaerobacter subterraneus: reassignment of T. subterraneus, Thermoanaerobacter yonseiensis, Thermoanaerobacter tengcongensis and Carboxydibrachium pacificum to Caldanaerobacter subterraneus gen. nov., sp. nov., comb. nov. as four novel subspecies.

Novel thermophilic, anaerobic, Gram-positive, rod-shaped bacteria, strains SL9 and OCA1, were isolated from oilfields in France and Australia, respectively. Both strains, together with Thermoanaerobacter yonseiensis KB-1(T) (=DSM 13777(T)), Thermoanaerobacter tengcongensis MB4(T) (=DSM 15242(T)) and Carboxydibrachium pacificum JM(T) (=DSM 12653(T)), possessed genomic (DNA-DNA hybridization studies) and phylogenetic similarities with Thermoanaerobacter subterraneus SEBR 7858(T) (=DSM 13054(T)), which was isolated recently from an oilfield reservoir in south-west France. Marked phenotypic differences exist between the three oilfield isolates (T. subterraneus, strain OCA1 and strain SL9): they include temperature range for growth and substrates used. Differences were also observed in the DNA G+C contents of all organisms. Similarly to T. subterraneus, strains SL9 and OCA1, and also T. yonseiensis, T. tengcongensis and Carboxydibrachium pacificum, produced acetate and L-alanine as major end products of glucose metabolism [0.8-1.0 mol L-alanine produced (mol glucose consumed)(-1)] and reduced thiosulfate, but not sulfate, to sulfide. Because of these significant metabolic and phylogenetic differences between the oilfield isolates (T. subterraneus, strain OCA1 and strain SL9), T. yonseiensis, T. tengcongensis and Carboxydibrachium pacificum and other Thermoanaerobacter species, it is proposed to reassign them as a novel genus and species, Caldanaerobacter subterraneus gen. nov., sp. nov., comb. nov., with the creation of four novel subspecies, Caldanaerobacter subterraneus subsp. subterraneus subsp. nov., comb. nov., Caldanaerobacter subterraneus subsp. yonseiensis subsp. nov., comb. nov., Caldanaerobacter subterraneus subsp. tengcongensis subsp. nov., comb. nov. and Caldanaerobacter subterraneus subsp. pacificus subsp. nov., comb. nov.

Petrotoga mexicana sp. nov., a novel thermophilic, anaerobic and xylanolytic bacterium isolated from an oil-producing well in the Gulf of Mexico.

A novel anaerobic, thermophilic, xylanolytic, motile rod-shaped bacterium with a sheath-like outer structure (toga) was isolated from a Mexican oil well in the Gulf of Mexico. Strain MET12T was a Gram-negative bacterium, reducing elemental sulfur, thiosulfate and sulfite to hydrogen sulfide. Its optimum growth conditions were 55 degrees C, pH 6.6, 3% NaCl and 0.15% MgCl2.6H2O. The DNA G+C content was 36.1 mol%. Phylogenetically, strain MET12T was related to members of genus Petrotoga, with similarities to Petrotoga mobilis, Petrotoga sibirica, Petrotoga miotherma and Petrotoga olearia varying from 97.6 to 98.8%. However DNA-DNA relatedness values between these species and strain MET12T were lower than 70%. As strain MET12T (=DSM 14811T=CIP 107371T) was genomically and phenotypically different from existing Petrotoga species, it is proposed as the type strain of a novel species, Petrotoga mexicana sp. nov.

Clostridium tunisiense sp. nov., a new proteolytic, sulfur-reducing bacterium isolated from an olive mill wastewater contaminated by phosphogypse.

A new sporulated fermentative bacterium designated strain E1(T) (T=type strain), was isolated from an anaerobic mud of an olive mill wastewater basin contaminated by phosphogypse produced by a Tunisian factory. Strain E1(T) was a motile Gram-positive slightly curved rod with spherical terminal spore swelling the cell. It grew between 18 degrees C and 43 degrees C with an optimum at 37 degrees C and pH 7.8 (range 5.5-8.7), without NaCl (range 0-3%). Strain E1(T) was a chemoorganotrophic anaerobic bacterium fermenting only proteins and amino acids. Yeast extract was required for growth. Elemental sulfur was used as terminal electron acceptor. The G+C content of the DNA was 32.6 mol%. The closest phylogenetical relatives of strain E1(T) were Clostridium thiosulfatireducens and C. subterminale (97.3% similarity for partial rRNA gene sequences). DNA-DNA hybridization values between strain E1(T) and both species were 17% and 20.8%, respectively. On the basis of differences in genotypic and phenotypic characteristics, strain E1(T) (DSM 15206(T), CIP 107666(T)) is proposed as the type strain of a new species, C. tunisiense sp. nov. GenBank accession number for the 16S rRNA gene sequence of strain E1(T) is AY187622.

Desulfonauticus submarinus gen. nov., sp. nov., a novel sulfate-reducing bacterium isolated from a deep-sea hydrothermal vent.

A novel moderately thermophilic, hydrogenotrophic, sulfate-reducing bacterium, strain 6N(T) (=DSM 15269(T)=CIP 107713(T)), was isolated from matrixes of Alvinella and Riftia originating from deep-sea hydrothermal-vent samples collected on the 13 degrees N East-Pacific Rise at a depth of approximately 2600 m. It was a Gram-negative, non-sporulating, curved rod, motile with one polar flagellum, that did not possess desulfoviridin. It grew at temperatures ranging from 30 to 60 degrees C, with an optimum at 45 degrees C, in the presence of 0-5 % NaCl (optimum 2 %). Strain 6N(T) utilized only H(2)/CO(2) and formate as electron donors with acetate as carbon source. Sulfate, sulfite, thiosulfate and elemental sulfur were used as terminal electron acceptors during hydrogen oxidation. The G+C content of DNA was 34.4 mol%. Strain 6N(T) grouped with members of the family Desulfohalobiaceae in the delta-subclass of the PROTEOBACTERIA: Its closest phylogenetic relative was Desulfonatronovibrio hydrogenovorans, with only 90 % similarity between the sequences of the genes encoding 16S rRNA. Because of significant phylogenetic differences from all sulfate-reducing bacteria described so far in the domain Bacteria, this novel thermophile is proposed to be assigned to a new genus and species, Desulfonauticus submarinus gen. nov., sp. nov.

Clostridium caminithermale sp. nov., a slightly halophilic and moderately thermophilic bacterium isolated from an Atlantic deep-sea hydrothermal chimney.

A strictly anaerobic, slightly halophilic and moderately thermophilic, sporulating rod designated strain DVird3T was isolated from deep-sea hydrothermal vent samples collected at a depth of approximately 800 m on the Atlantic Ocean Ridge. Strain DVird3T possessed a few laterally inserted flagella, had a DNA G + C content of 33.1 mol% and grew optimally at pH 6.6 and at 45 degrees C. Growth was observed at temperatures between 20 and 58 degrees C and at pH values between 5.8 and 8.2. The optimum NaCl concentration for growth was 3% sea salt (30 g l(-1)); no growth was observed in the presence of 15 or 60 g sea salt l(-1). Strain DVird3T is heterotrophic and utilizes some sugars and various single amino acids. Acetate was the main fatty acid detected from carbohydrate fermentation, together with H2 and CO2. Gelatin was used as an energy source. It performed the Stickland reaction. Phylogenetically, strain DVird3T branched with members of cluster XI of the order Clostridiales, with Clostridium halophilum as its closest relative (similarity of 94.6%). On the basis of its phenotypic, genotypic and phylogenetic characteristics, strain DVird3T (= DSM 15212T = CIP 107654T) is proposed as the type strain of a novel species of the genus Clostridium, Clostridium caminithermale sp. nov.

Degradation of cinnamate via beta-oxidation to benzoate by a defined, syntrophic consortium of anaerobic bacteria.

A syntrophic consortium was enriched in a basal medium containing cinnamate as the carbon and energy source. It was found to consist of three morphologically distinct microbes, viz., a short, rod-shaped, non-motile bacterium with distinctly pointed ends, Papillibacter cinnamivorans; a rod-shaped, motile bacterium with rounded ends, Syntrophus sp.; and a methanoarchaeon, Methanobacterium sp. This methanogen was then replaced by a collection strain of Methanobacterium formicicum. A syntrophic interdependency of the three partners of the consortium was observed during growth on cinnamate. In the presence of bromoethanesulfonic acid (BESA), cinnamate was transformed to benzoate, whereas under methanogenic conditions without BESA, cinnamate was first transformed to benzoate via beta-oxidation and subsequently completely degraded into acetate, CH(4), and CO(2). Papillibacter cinnamivorans was responsible for benzoate production from cinnamate, whereas a syntrophic association between Syntrophus sp. and the methanogen degraded benzoate to acetate, CH(4), and CO(2). A new anaerobic degradation pathway of cinnamate into benzoate via beta-oxidation by a pure culture of P. cinnamivorans is proposed.

Desulfovibrio capillatus sp. nov., a novel sulfate-reducing bacterium isolated from an oil field separator located in the Gulf of Mexico.

A new spirilloid sulfate-reducing bacterium designated strain MET2(T) (T=type strain), was isolated from a Mexican oil field separator. Electron microscopy revealed a Gram-negative cell wall consisting of a 150nm thick undulating outer membrane. Strain MET2(T) appeared singly or in long chains and was actively motile with a corkscrew-like motion. The isolate grew optimally at 40 degrees C, pH 7.4 and 3% NaCl in a medium containing lactate, thiosulfate and yeast extract. Sulfate, sulfite, thiosulfate, and elemental sulfur served as electron acceptors but not nitrate or fumarate. Lactate, pyruvate and H(2) (with acetate as carbon source) were used as electron donors. Pyruvate was fermented. Desulfoviridin and cyt c were present. The G+C content of the DNA was 58.7mol%. Phylogenetic analysis based on 16S rDNA sequencing showed that strain MET2(T) was a member of the genus Desulfovibrio with "D. gracilis" and D. longus being its closest relatives (similarities of 98.3% and 97.1%, respectively). However, DNA-DNA hybridization studies indicated poor homologies (values <70%) with both species. On the basis of genotypic, phenotypic, and phylogenetic characteristics, strain MET2(T) (=DSM14982(T)=CIP107483(T)) is proposed as the type strain of a new species, Desulfovibrio capillatus sp. nov. GenBank accession number for the 16S rDNA sequence for MET2(T) is AY176773.

Clostridium thiosulfatireducens sp. nov., a proteolytic, thiosulfate- and sulfur-reducing bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

A strictly anaerobic, gram-positive, sporulating rod (0.5-0.6 x 2.0-4.0 microm), designated strain Lup 21T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating cheese-factory wastewater. Strain Lup 21T was motile by means of peritrichous flagella, had a G+C content of 31.4 mol% and grew optimally at 37 degrees C, pH 7.4, in the absence of NaCl. It is a heterotrophic micro-organism, utilizing proteinaceous compounds (gelatin, peptides, Casamino acids and various single amino acids) but unable to use any of the carbohydrates tested as a carbon and energy source. It reduced thiosulfate and elemental sulfur to sulfide in the presence of Casamino acids as carbon and energy sources. Acetate, butyrate, isobutyrate, isovalerate, CO2 and sulfide were end products from oxidation of gelatin and Casamino acids in the presence of thiosulfate as an electron acceptor. In the absence of thiosulfate, serine, lysine, methionine and histidine were fermented. On the basis of 16S rRNA similarity, strain Lup 21T was related to members of the low-G+C Clostridiales group, Clostridium subterminale DSM 6970T being the closest relative (with a sequence similarity of 99.4%). DNA-DNA hybridization was 56% with this species. On the basis of phenotypic, genotypic and phylogenetic characteristics, the isolate was designated as a novel species of the genus Clostridium, Clostridium thiosulfatireducens sp. nov. The type strain is strain Lup 21T (= DSM 13105T = CIP 106908T).

Sporanaerobacter acetigenes gen. nov., sp. nov., a novel acetogenic, facultatively sulfur-reducing bacterium.

A strictly anaerobic, moderately thermophilic, sporulating rod, designated strain Lup 33T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor in Mexico. Strain Lup 33T possessed a few laterally inserted flagella, had a DNA G+C content of 32.2 mol % and grew optimally at pH 7.4 and 40 degrees C. Growth was observed at temperatures of up to 50 degrees C and was inhibited in the presence of 5% NaCl. Strain Lup 33T is heterotrophic and utilized some sugars, peptides and various single amino acids. Gelatin and casein were not used as energy sources. It performed the Stickland reaction and reduced elemental sulfur to sulfide. Acetate was the only fatty acid detected from glucose fermentation, whereas acetate together with isobutyrate and isovalerate were found as end products from peptone fermentation. Phylogenetically, strain Lup 33T branched with members of cluster XII of the order Clostridiales, with Clostridium hastiforme as the closest relative (similarity of 93%). On the basis of the phenotypic, genotypic and phylogenetic characteristics of the isolate, it is proposed as a novel species of a new genus, Sporanaerobacter acetigenes gen. nov., sp. nov. The type strain is strain Lup 33T (= DSM 13106T = CIP 106730T).

Isolation from a shea cake digester of a tannin-degrading Streptococcus gallolyticus strain that decarboxylates protocatechuic and hydroxycinnamic acids, and emendation of the species.

A facultatively anaerobic, mesophilic, non-motile, non-sporulating bacterium, designated strain B7, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds, after enrichment on tannic acid. The coccoid cells (less than 2 microm in diameter) occurred in pairs or short chains and stained gram-positive. Strain B7 fermented a wide range of carbohydrates (cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, melibiose, raffinose and trehalose), grew optimally at pH 7.0 and had a G+C content of 40.4+/-0.3 mol%. Strain B7 was closely related to Streptococcus gallolyticus ACM 3611T, a member of the Streptococcus bovis rRNA cluster, with a sequence similarity of 98% and a DNA hybridization value of 86 mol%. Isolate B7 hydrolysed tannic acid and decarboxylated gallic acid to pyrogallol, traits also observed in S. gallolyticus ACM 3611T. In addition, both strains decarboxylated protocatechuic acid to catechol, p-coumaric acid to 4-vinylphenol, caffeic acid to 4-vinylcatechol and ferulic acid to 4-vinylguaiacol. An unsubstituted para-hydroxyl group on the benzene ring was required for decarboxylation. Glucose addition markedly increased the conversion rate. As these traits were not described previously, emendation of the description of the species Streptococcus gallolyticus is proposed.

Evidence of interspecies hydrogen transfer from glycerol in saline environments.

Two halanaerobic bacteria--Halanaerobium saccharolytica subsp. senegalense and Halanaerobium sp. strain FR1H--produced acetate, H2, and CO2 from glycerol fermentation, but the glycerol consumption rate was low. In contrast, in the presence of the moderately halophilic hydrogenotrophic sulfate-reducing bacterium, Desulfohalobium retbaense, used as H2 scavenger in the coculture, glycerol oxidation by both halanaerobes significantly increased. Cocultures of both halanaerobes with D. retbaense on glycerol led to acetate, hydrogen sulfide, and CO2 production, whereas glycerol fermentation by the two strains led to the production of acetate, hydrogen, and CO2. The increased glycerol oxidation by H. saccharolytica and strain FRI H in coculture with D. retbaense resulted from low H2 partial pressure caused by the hydrogen-oxidizing activity of D. retbaense. These results provide the first evidence of interspecies hydrogen transfer in saline environments and indicate that this mechanism may play an important role in organic matter mineralization in hypersaline ecosystems.

Isolation from a shea cake digester of a tannin-tolerant Escherichia coli strain decarboxylating p-hydroxybenzoic and vanillic acids.

A facultatively anaerobic, mesophilic, Gram-negative, non-motile, non-sporulated bacterium, designated strain C2, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds and previously inoculated with anaerobic sludge from the pit of a slaughterhouse, after enrichment on tannic acid. The straight rods occurred singly or in pairs. Strain C2 fermented numerous carbohydrates (fructose, galactose, glucose, lactose, mannose, maltose, melibiose, raffinose, rhamnose, ribose, saccharose, sorbitol, trehalose, and xylose) and peptides (Biotrypcase, Casamino acids, and yeast extract), producing acid and gas, and had a G + C content of 51.6 +/- 0.1 mol %. Strain C2 was very closely related to Escherichia coli (= DSM 30083(T)) phylogenetically (similarity of 99%), genotypically (DNA homology of 79%), and phenotypically. The isolate tolerated tannic acid (hydrolyzable tannin) and decarboxylated by non-oxidative decarboxylation only p-hydroxybenzoic and vanillic acids to their corresponding phenol and guaicol, under anaerobic and aerobic conditions without further degradation. Adding glucose increased growth and the rate of conversion. High concentrations of p-hydroxybenzoic acid or vanillic acid inhibited growth, and decarboxylation could not occur completely, suggesting phenol toxicity. In contrast, the type strain of E. coli cannot metabolize p-hydroxybenzoic and vanillic acids, anaerobically or aerobically, with or without glucose added.