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Sterculic acid, 8-(2-octyl-1-cyclopropenyl)octanoic acid, is a potent inhibitor of the enzyme system converting stearic acid to oleic acid in Chlorella vulgaris. No inhibition of oleic acid formation from acetate, is, however, observed. With the C10, Cn or C14 acids as precursor, inhibition increases with chain length. The enzyme system converting oleic acid to linoleic acid is also less sensitive than the stearate-oleate system. Stearic acid generated internally in leaf preparations anaerobically from acetate is still converted to oleic acid on transference to air in the presence of sterculic acid. Desaturation of added palmitic acid is readily inhibited by sterculic acid, so far as formation of the Δ7 and Δ9 acids are concerned. Desaturation of palmitic acid to the 3-trans-hexadecenoic acid is unaffected by sterculic acid. Two possible schemes to account for the effects of sterculic acid on stearate desaturation are suggested. [ABSTRACT FROM AUTHOR]

Mutants of Moraxella caleoacetica which synthesize constitutively β-ketoadipate succinyl-CoA transferase, but in which all other enzymes of the β-ketoadipate pathway are still normally inducible, have been isolated by selection for the ability to grow with β-ketoadipate. The constitutively synthesized transferase was identified as transferase III. This enzyme is induced in the wild type by adipate and its physiological function is probably adipate activation. The properties of these constitutive mutants confirm that the synthesis of transferase III is regulated independently of the synthesis of enzymes that mediate reactions of the β-ketoadipate pathway. Two phenotypically different classes of mutants which synthesize transferase II constitutively have also been isolated by the same selective procedure. Both classes of mutants synthesize constitutively the five enzymes that convert catechol to β-ketoadipyl-CoA. Strict coordinacy between four of these enzymes (muconate lactonizing enzyme, muconolactone isomerase, β-ketoadipate enol-lactone hydrolase II and β-ketoadipate succinyl-CoA transferase II) is maintained in one class of mutants. However in the other class this coordinacy is destroyed and muconate lactonizing enzyme is synthesized in succinate-grown cells at a relative level much lower than those of the other three enzymes. These findings are discussed and evaluated in terms of earlier evidence concerning the regulation of the synthesis of enzymes of the catechol branch by M. calcoacetica. [ABSTRACT FROM AUTHOR]

Background: Surgical site infections (SSIs) have been shown to increase patient morbidity and mortality, impact on quality of life and place a significant economic burden on healthcare systems worldwide. Irrigation using wound cleansing and antiseptic effective solutions during surgical procedures is a key part of SSI prevention. The optimal solution would have minimal cytotoxicity to the patient while maintaining a minimum concentration required for antimicrobial activity necessary to prevent opportunistic pathogens and biofilm formation., Method: A variety of common wound irrigation products, including polyhexanide in various concentrations and compositions, iodine and hypochlorous acid-based solutions, were tested and compared for their activity against pathogens according to the ESKAPE group of nosocomial relevant microbes. The antimicrobial efficacy of the solutions was tested against planktonic cells using a time-kill assay. Its minimal bactericidal concentration (MBC) and its cytotoxicity against mouse fibroblast cells were determined. Finally, the Therapeutic Index (TI) was compared and the biofilm activity of a selected solution containing 0.1% polyhexanide (PHMB) was tested., Results: Irrigation solutions containing 0.1% PHMB demonstrated rapid inactivation against planktonic cultures, achieving >4 lg reduction within 60 seconds. When comparing the TI of all irrigation solutions tested, the combination of 0.1% PHMB and poloxamer as an additive showed the best results in killing nosocomial pathogens and also to be less cytotoxic to mammalian fibroblasts, as demonstrated for PREVENTIA ® Surgical Irrigation. When exposed to five single-species biofilms, PREVENTIA ® Surgical Irrigation showed a 3 lg reduction (average) after 60 minutes; this was supported by microscopy showing significant biofilm disruption and an abundance of non-viable microcolony formations., Conclusion: This study highlights the impact of irrigation solutions containing PHMB. It also demonstrated the effect of using different concentrations of PHMB in combination with surfactants as additives. The combination of 0.1% PHMB and poloxamer as a surfactant demonstrated effective benefits in eradicating established biofilm combined with a relatively high Therapeutic Index (TI), indicating low cytotoxicity and high bactericidal activity., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2024 Watson et al.)

Eschar and slough in wounds serve as a reservoir for microorganisms and biofilms, damaged/devitalised cells, and inflammatory chemokines/cytokines, which work to initiate and prolong persistent inflammation and increase the risk of infection. Biofilm-related inflammation and infections are considered to be highly prevalent in acute wounds and chronic wounds. As slough is known to harbour biofilms, measuring the efficacy of antimicrobials in killing microbes both within and under slough is warranted. This highlights the need for more clinically relevant wound biofilm models to address this significant clinical need. Consequently, in this study, we developed an in vitro artificial wound slough (AWS) biofilm model produced by forming a biofilm below a layer of AWS, the latter of which was composed of the main protein components reported in wound eschar and slough, namely collagen, elastin, and fibrin. The model was employed to investigate the antibiofilm and antibacterial efficacy of a new patented smart next-generation antibiofilm technology composed of silver-zinc EDTA complexes and designed as a family of multifunctional metal complexes referred to as MMCs, in a liquid format, and to determine both the performance and penetration through AWS to control and manage biofilms. The results demonstrated the ability of the AWS-biofilm model to be employed for the evaluation of the efficacy of a new antibiofilm and antimicrobial next-generation smart technology. The results also demonstrated the potential for the proprietary EDTA multifunctional metal complexes to be used for the disruption of biofilms, such as those that form in chronic wounds.

Confusion exists as to whether the oocytes of the domestic horse are ovulated at the first meiotic metaphase (MI) or the second (MII). In this study eight oocytes were collected from the preovulatory follicles of 16 mares 36 h after human chorionic gonadotropin CG treatment. Six of the eight oocytes were judged to be at MII by the presence of the first polar body and this judgement was confirmed by semithin sectioning in one. Of the two that had no polar body, one was found to be at MII after fixation for chromosomal analysis and the meiotic stage of the other remained undetermined. Since all seven oocytes yielding conclusive evidence were at MII, it was concluded that horse oocytes, like those of most mammals studied, are ovulated after completion of the first meiotic division and formation of the first polar body.