1. Glycyl-alanyl-histidine protects PC12 cells against hydrogen peroxide toxicity
Hideki Shimura, Ryota Tanaka, Yoshiaki Shimada, Kazuo Yamashiro, Nobutaka Hattori, Takao Urabe BMC Biochem. 2017 Nov 22;18(1):14. doi: 10.1186/s12858-017-0089-x.
Background: Peptides with cytoprotective functions, including antioxidants and anti-infectives, could be useful therapeutics. Carnosine, β-alanine-histidine, is a dipeptide with anti-oxidant properties. Tripeptides of Ala-His-Lys, Pro-His-His, or Tyr-His-Tyr are also of interest in this respect. Results: We synthesized several histidine-containing peptides including glycine or alanine, and tested their cytoprotective effects on hydrogen peroxide toxicity for PC12 cells. Of all these peptides (Gly-His-His, Ala-His-His, Ala-His-Ala, Ala-Ala-His, Ala-Gly-His, Gly-Ala-His (GAH), Ala-His-Gly, His-Ala-Gly, His-His-His, Gly-His-Ala, and Gly-Gly-His), GAH was found to have the strongest cytoprotective activity. GAH decreased lactate dehydrogenase (LDH) leakage, apoptosis, morphological changes, and nuclear membrane permeability changes against hydrogen peroxide toxicity in PC12 cells. The cytoprotective activity of GAH was superior to that of carnosine against hydrogen peroxide toxicity in PC12 cells. GAH also protected PC12 cells against damage caused by actinomycin D and staurosporine. Additionally, it was found that GAH also protected SH-SY5Y and Jurkat cells from damage caused by hydrogen peroxide, as assessed by LDH leakage. Conclusion: Thus, a novel tripeptide, GAH, has been identified as having broad cytoprotective effects against hydrogen peroxide-induced cell damage.
2. His-Ala-Phe-Lys peptide from Burkholderia arboris possesses antifungal activity
Huajie Zhu, Cuihong Xu, Yicun Chen, Yan Liang Front Microbiol. 2022 Dec 6;13:1071530. doi: 10.3389/fmicb.2022.1071530. eCollection 2022.
Burkholderia arboris, which belongs to the Burkholderia cepacia complex, has been shown to possess antifungal activity against several plant fungal pathogens; however, the antifungal compounds are yet to be identified. Here, we identified the antifungal compounds produced by B. arboris using genetic and metabolomic approaches. We generated a Tn5 transposon mutation library of 3,000 B. arboris mutants and isolated three mutants with reduced antifungal activity against the plant fungal pathogen Fusarium oxysporum. Among the mutants, the M464 mutant exhibited the weakest antifungal activity. In the M464 genome, the transposon was inserted into the cobA gene, encoding uroporphyrin-III methyltransferase. Deletion of the cobA gene also resulted in reduced antifungal activity, indicating that the cobA gene contributed to the antifungal activity of B. arboris. Furthermore, a comparison of the differential metabolites between wild type B. arboris and the ∆cobA mutant showed a significantly decreased level of tetrapeptide His-Ala-Phe-Lys (Hafk) in the ∆cobA mutant. Therefore, a Hafk peptide with D-amino acid residues was synthesized and its antifungal activity was evaluated. Notably, the Hafk peptide displayed significant antifungal activity against F. oxysporum and Botrytis cinerea, two plant pathogens that cause destructive fungal diseases. Overall, a novel antifungal compound (Hafk) that can be used for the biocontrol of fungal diseases in plants was identified in B. arboris.
3. Human "autotomy"
David Bowsher Pain. 2002 Jan;95(1-2):187-9. doi: 10.1016/s0304-3959(01)00389-x.
We describe two cases of self-injurious behaviour. One was a man with central post-stroke pain with maximal pain in the tip of the nose, who excavated his ala nasae--in which he subsequently continued to experience phantom pain. The second case a man who, following ophthalmic herpes zoster and possibly mild postherpetic neuralgia. He subsequently scratched his anaesthetic forehead down to the bone, while denying he experienced any pain. We would describe the first case as one of true autotomy; but the second as destruction of an anaesthetic part of the body. The implications for human and animal physiopathology are discussed.
