Highlights • Metabolic engineering can be used to address major challenges in lactic acid production. • Challenges include lactate purity, acid tolerance, carbon source and fermentation parameters. • ...Rational and evolutionary engineering are major metabolic engineering strategies. • Future developments are expected to enhance biomass utilization in lactate production.
Recent evidence has implicated single-stranded DNA-binding protein (SSB) expression level as an important factor in microbial radiation resistance. The genome of the extremely radiation resistant ...bacterium Deinococcus radiodurans contains genes for two SSB homologs: the homodimeric, canonical Ssb, encoded by the gene ssb, and a novel pentameric protein encoded by the gene ddrB. ddrB is highly induced upon exposure to radiation, and deletions result in decreased radiation-resistance, suggesting an integral role of the protein in the extreme resistance exhibited by this organism. Although expression of ssb is also induced after irradiation, Ssb is thought to be involved primarily in replication. In this study, we demonstrate that Ssb in D. radiodurans is essential for cell survival. The lethality of an ssb deletion cannot be complemented by providing ddrB in trans. In addition, the radiation-sensitive phenotype conferred by a ddrB deletion is not alleviated by providing ssb in trans. By altering expression of the ssb gene, we also show that lower levels of transcription are required for optimal growth than are necessary for high radiation resistance. When expression is reduced to that of E. coli, ionizing radiation resistance is similarly reduced. UV resistance is also decreased under low ssb transcript levels where growth is unimpaired. These results indicate that the expression of ssb is a key component of both normal cellular metabolism as well as pathways responsible for the high radiation tolerance of D. radiodurans.
The haloarchaea are unusual in possessing genes for multiple homologs to the ubiquitous single-stranded DNA binding protein (SSB or replication protein A, RPA) found in all three domains of life.
...contains five homologs: two are eukaryotic in organization, two are prokaryotic and are encoded on the minichromosomes, and one is uniquely euryarchaeal. Radiation-resistant mutants previously isolated show upregulation of one of the eukaryotic-type RPA genes. Here, we have created deletions in the five RPA operons. These deletion mutants were exposed to DNA-damaging conditions: ionizing radiation, UV radiation, and mitomycin C. Deletion of the euryarchaeal homolog, although not lethal as in
, causes severe sensitivity to all of these agents. Deletion of the other RPA/SSB homologs imparts a variable sensitivity to these DNA-damaging agents, suggesting that the different RPA homologs have specialized roles depending on the type of genomic insult encountered.
Depuis une dizaine d’années, le nombre de mastectomies bilatérales prophylactiques avec reconstruction prothétique est en constante augmentation. Nous décrivons une nouvelle stratégie et analysons sa ...faisabilité et sa sécurité.
Il s’agit d’une étude rétrospective descriptive monocentrique. Le premier temps opératoire consistait à obtenir une capsule péri-prothétique autour d’implants et corriger une éventuelle ptose ou hypertrophie mammaire. Lors du second temps était réalisée une mastectomie avec conservation de l’étui cutané et de la plaque aréolo-mamelonaire et changement des implants pour un volume supérieur. Le troisième temps était consacré au lipofilling.
Sept patientes ont été incluses dont 6 avec mutation BRCA1. L’âge moyen était de 35,6 ans 29,6 ; 41,6, l’IMC moyen de 23,8kg/m2 20,6 ; 27, le tour de poitrine moyen à 93,7cm 87,4 ; 100, le bonnet moyen C- B- ; D-. 4 femmes avaient une ptose ou une hypertrophie mammaire. Le nombre moyen d’intervention par femme était de 3,6 2,5 ; 4,7. Le volume moyen des implants était de 248,6mL 211,3 ; 285,9. Le deuxième temps était réalisé en moyenne 33,9 semaines 22,3 ; 45,5 plus tard. L’augmentation moyenne du volume des prothèses était de 120mL 80,4 ; 159,6. 4 patientes ont présenté des complications dont 1 exposition de prothèse. 6 patientes ont bénéficié d’un lipofilling d’un volume moyen par sein de 175mL 116 ; 234.
Les avantages seraient de diminuer le taux de complications, d’améliorer le résultat esthétique et de diminuer l’impact psychologique de la chirurgie.
For the past decades, number of prophylactic bilateral mastectomies using reconstruction with implants increases. We describe a new surgical strategy and analyse its safety and feasability.
It is a retrospective, descriptive and monocentric study. The first step of surgery consisted in obteining a peri-prosthetic capsule with implants and if there was a mammary hypertrophy and/or ptosis, it was corrected at the same time. The second step of surgery was the nipple-sparing mastectomy with change of implants for bigger ones. Third step consisted in a lipofilling.
Seven patients were included. 6 women had a BRCA1 gene mutation. Mean age was 35.6 year-old 29.6; 41.6, mean BMI was 23.8kg/m2 20.6; 27, mean chest circumference was 93.7cm 87.4; 100, mean cup was C– B–; D–. 4 women had mammary hypertrophy and/or ptosis. Mean number of procedure per woman was 3.6 2.5; 4.7. Mean volume of implants used at the first step was 248.6ml 211.3; 285.9. The second step was performed mean 33.9 weeks 22.3; 45.5 later. Mean increase of implants volume was 120ml 80.4; 159.6. 4 patients had complications including 1 who had implant exposure. Six patients had lipofilling of mean volume per breast of 175ml 116; 234.
This new strategy could decrease complication rate, improve aesthetic outcome and decrease psychological impact of surgery.
BACKGROUNDFor the past decades, number of prophylactic bilateral mastectomies using reconstruction with implants increases. We describe a new surgical strategy and analyse its safety and feasability. ...METHODIt is a retrospective, descriptive and monocentric study. The first step of surgery consisted in obteining a peri-prosthetic capsule with implants and if there was a mammary hypertrophy and/or ptosis, it was corrected at the same time. The second step of surgery was the nipple-sparing mastectomy with change of implants for bigger ones. Third step consisted in a lipofilling. RESULTSSeven patients were included. 6 women had a BRCA1 gene mutation. Mean age was 35.6 year-old 29.6; 41.6, mean BMI was 23.8kg/m2 20.6; 27, mean chest circumference was 93.7cm 87.4; 100, mean cup was C- B-; D-. 4 women had mammary hypertrophy and/or ptosis. Mean number of procedure per woman was 3.6 2.5; 4.7. Mean volume of implants used at the first step was 248.6ml 211.3; 285.9. The second step was performed mean 33.9 weeks 22.3; 45.5 later. Mean increase of implants volume was 120ml 80.4; 159.6. 4 patients had complications including 1 who had implant exposure. Six patients had lipofilling of mean volume per breast of 175ml 116; 234. CONCLUSIONThis new strategy could decrease complication rate, improve aesthetic outcome and decrease psychological impact of surgery.
Ballistics gelatin is a common tissue surrogate used in bacterial contamination models for projectile wounds. Although these studies have demonstrated that bacteria are transferred from the surface ...of the gelatin to the wound track by a projectile, quantifiable results have been inconsistent and not repeatable in successive tests.
In this study, five areas of a typical contamination model in which bacterial recovery or survival are affected were identified for optimization. The first was a contaminated "skin" surrogate, where the novel use of vacuum filtration of a bacterial culture and buffer onto filter paper was employed. The other possibly problematic areas of the bacterial distribution model included the determination of bacterial survival when the contamination model is dried, survival in solid and molten gelatin, and the effect of high-intensity lights used for recording high-speed video.
Vacuum filtration of bacteria and buffer resulted in a consistent bacterial distribution and recovery. The use of phosphate buffer M9 (pH 7) aided in neutralizing the ballistics gelatin and improving bacterial survival in solid gelatin. Additionally, the use of high-intensity lights to record high-speed video and the use of a 42
C water bath to melt the gelatin were found to be bactericidal for gram-positive and gram-negative bacteria.
Multiple areas of a typical contamination model in which bacterial survival may be impeded were identified, and methods were proposed to improve survival in each area. These methods may be used to optimize the results of bacterial contamination models for medical applications, such as understanding the progression of infection in penetrating wounds and to identify possible sources of contamination for forensic purposes.
Les brûlures chimiques sont rares mais entraînent des lésions cutanées souvent profondes. Les agents basiques possèdent un pouvoir pénétrant fort et prolongé, provoquant des brûlures évolutives sur ...plusieurs jours. Le traitement local de ces patients est chirurgical associant excision et couverture par greffe de peau mince. Réalisées précocement dans un contexte d’agent chimique, ces greffes sont de prise difficile, retardant la cicatrisation. Nous proposons donc pour ces patients de différer la greffe de peau mince, 10jours après l’excision de la brûlure. Nous présentons une étude comparative originale et nouvelle pour évaluer notre stratégie chirurgicale en deux temps.
Nous avons réalisé une étude rétrospective des patients victimes de brûlures profondes par agents basiques pris en charge dans le centre des brûlés de Lille. Les caractéristiques épidémiologiques et les modalités de prise en charge chirurgicales ont été étudiées sur dossier. Nous avons comparé la durée de cicatrisation et le taux de lyse de greffes de peau chez les patients ayant bénéficié d’une couverture initiale (témoins) ou secondaire (cas) après excision. Cette comparaison a été possible après appariement sur l’âge et le sexe.
Notre population a inclus 25 témoins et 16 cas. Les hommes étaient majoritairement atteints avec un âge moyen de 41,9 ans. Les brûlures étaient localisées dans 78 % des cas aux membres inférieurs. Le délai entre la brûlure et l’excision était en moyenne de 16,5jours. Chez les cas, la greffe de peau mince était réalisée en moyenne 11,3jours après l’excision initiale. Nous n’avons pas mis en évidence de différence significative entre les deux groupes pour la surface corporelle totale atteinte, la topographie des brûlures et l’agent causal. La durée de cicatrisation était significativement plus courte chez les cas par rapport aux témoins (37,5jours vs 50,3jours ; p<0,025). On observait de plus une diminution du nombre de lyse de greffes chez les cas par rapport aux témoins (13,3 % vs 46,7 % ; p=0,059).
Notre étude montre l’intérêt d’une stratégie chirurgicale en deux temps chez les patients victimes de brûlures par agents basiques. L’excision dite précoce associée à la réalisation d’une greffe de peau mince dans un second temps permet une cicatrisation plus rapide et diminue les risques de lyse de greffe.
Chemical burns are rare but often lead to deep cutaneous lesions. Alkali agents have a deep and long lasting penetrating power, causing burns that evolve over several days. The local treatment for these patients is excision of the wound and split thickness skin graft. Early excision and immediate skin grafting of alkali burns are more likely to be complicated by graft failure and delayed wound healing. We propose a two-step method that delays skin grafting until two-three days after burn wound excision.
Our population included 25 controls and 16 cases. Men were predominant with a mean age of 41.9 years. In 78% of cases, burns were located on the lower limbs. The mean delay between the burn and excision was 16.5 days. In cases, the skin graft was performed at a mean of 11.3 days after the initial excision. We did not unveil any significant difference between both groups for the total skin surface affected, topography of the burns and the causal agent. Wound healing was significantly shorter in cases vs controls (37.5 days vs 50.3 days; P<0.025). Furthermore, we observed a decreased number of graft failures in cases vs controls (13.3% vs 46.7%; P=0.059).
Our study shows the relevance of a two-step surgical strategy in patients with alkali chemical burns. Early excision followed by interval skin grafting is associated with quicker wound healing and decreased rate of graft failure.
L’expansion des parties molles, particulièrement de la peau, constitue un procédé ancien et physiologique afin d’augmenter le capital cutané permettant l’exérèse de lésions tout en comblant la perte ...de substance induite. Simple dans son principe, ce procédé est soumis à des contraintes chez l’enfant nécessitant une planification précise et une réalisation technique rigoureuse. Entre 1990 et 2016, nous avons réalisé 293 protocoles d’expansion avec 411 prothèses chez 244 enfants. Le scalp était la zone la plus concernée (158 cas), suivi par le tronc (29). Le nævus congénital représentait l’indication la plus fréquente (119 cas), suivi des séquelles de brûlures et de cicatrices (64 cas), puis de l’hamartome sébacé de Jadassohn (27 cas). Trois catégories d’indication peuvent être établies. Les indications idéales sont les expansions sur le cuir chevelu, la préparation cutanée avant l’ablation d’un nævus de grande taille, l’hamartome sébacé de Jadhasson et le sein hypoplasique sévère de l’adolescente. Les indications courantes mais plus délicates sont les séquelles cicatricielles et en particulier après brûlures, le traitement du cutis aplasia du vertex et les expansions sur les membres, l’abdomen ou cervicofaciales. Les indications d’exception comprennent la séparation de siamois, ou la protection de l’intestin avant irradiation. Les contre-indications sont les lésions infectées, les tumeurs malignes et les lésions nécessitant une couverture urgente. Si le principe de l’expansion est relativement simple, son positionnement sur l’échelle des méthodes de reconstruction l’est moins du fait du risque de complications non négligeables.
The expansion of soft tissue, especially skin, is an old and physiological process to increase the skin reserve allowing excision while coveraging of the resulting loss of substance. Easy in principle, this process is subjected to constraints in children requiring precise planning and rigorous technical procedure. Between 1990 and 2016, we performed 293 expansion protocols with 411 implants in 244 children. The scalp was the most interested area (158 cases), followed by the trunk (29). The congenital nevi represented the most frequent indication (119 cases), followed by sequelae of burns and scars (64 cases) and hamartoma sebaceous of Jadassohn (27 cases). Three categories of indication can be established. Ideal indications of the expansion are on the scalp, skin preparation prior to the excision of a large nevus, nevus sebaceous of Jadhasson and severe breast hypoplasia. Common but delicate indications are scars, especially after burns, treatment of vertex aplasia cutis congenita and expansions of the limbs, abdomen, head and neck. Rare indications include separation of Siamese twins, or protection of the bowel before radiotherapy. Contra-indications are infected lesions, malignant tumors and lesions requiring immediate coverage. If the principle of expansion is relatively simple, its positioning on the scale of reconstruction methods is harder because of the risk of significant complications.
Chemical burns are rare but often lead to deep cutaneous lesions. Alkali agents have a deep and long lasting penetrating power, causing burns that evolve over several days. The local treatment for ...these patients is excision of the wound and split thickness skin graft. Early excision and immediate skin grafting of alkali burns are more likely to be complicated by graft failure and delayed wound healing. We propose a two-step method that delays skin grafting until two-three days after burn wound excision.
Our population included 25 controls and 16 cases. Men were predominant with a mean age of 41.9 years. In 78% of cases, burns were located on the lower limbs. The mean delay between the burn and excision was 16.5 days. In cases, the skin graft was performed at a mean of 11.3 days after the initial excision. We did not unveil any significant difference between both groups for the total skin surface affected, topography of the burns and the causal agent. Wound healing was significantly shorter in cases vs controls (37.5 days vs 50.3 days; P<0.025). Furthermore, we observed a decreased number of graft failures in cases vs controls (13.3% vs 46.7%; P=0.059).
Our study shows the relevance of a two-step surgical strategy in patients with alkali chemical burns. Early excision followed by interval skin grafting is associated with quicker wound healing and decreased rate of graft failure.
Cellulomonas sp. strain ES6 is a chromate-reducing bacterium isolated from chromium contaminated subsurface sediment. Illumina MiSeq and Oxford Nanopore sequencing were used to assemble the genome ...sequence which consisted of a single circular chromosome of 4.13 Mb, contained 3,960 protein encoding genes and with an overall G + C content 75.38%.
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