Molecular characterization and functional analysis of IL-18 in snakehead (Channa argus) during Aeromonas schubertii and Nocardia seriolae infections.

As a proinflammatory cytokine of the interleukin-1 (IL-1) family, IL-18 plays important roles in host protection against bacterial, viral, and fungal infection. We cloned the open reading frame of snakehead (Channa argus) IL-18 (shIL-18) and found that it contained 609 base pairs and encoded 202 amino acid residues. The shIL-18 included a conserved IL-1-like family signature and two potential IL-1ß-converting enzyme cutting sites; one was conserved in all analyzed IL-18s, but the other was unique to shIL-18. Unlike other IL-18s, shIL-18 also contained a predicted signal peptide. In this study, shIL-18 was constitutively expressed in all tested tissues, and its expression was induced by Aeromonas schubertii and Nocardia seriolae in the head kidney and spleen in vivo and by lipoteichoic acid, lipopolysaccharides, and polyinosinic-polycytidylic acid in head kidney leukocytes in vitro. Moreover, recombinant shIL-18 upregulated the expression of interferon-γ, IL-1ß, and tumor necrosis factor-α1 and -α2 and promoted the proliferation of leukocytes. Taken together, these results showed that IL-18 played crucial roles in host defense against bacterial infection in fish, as it does in mammals.

Dehydropropylpantothenamide isolated by a co-culture of Nocardia tenerifensis IFM 10554T in the presence of animal cells.

A new amide, named dehydropropylpantothenamide (1), was obtained by a co-culture of Nocardia tenerifensis IFM 10554T in the presence of the mouse macrophage-like cell line J774.1 in modified Czapek-Dox (mCD) medium. Compound 1 was synthesized from D-pantothenic acid calcium salt in 6 steps. The absolute configuration of natural compound 1 was determined by comparisons of the optical rotation and CD spectra of synthetic 1. In the present study, a new method for producing secondary metabolites was demonstrated using a "co-culture" in which the genus Nocardia was cultured in the presence of an animal cell line.

Epidermal Growth Factor Receptor Expression Licenses Type-2 Helper T Cells to Function in a T Cell Receptor-Independent Fashion.

Gastro-intestinal helminth infections trigger the release of interleukin-33 (IL-33), which induces type-2 helper T cells (Th2 cells) at the site of infection to produce IL-13, thereby contributing to host resistance in a T cell receptor (TCR)-independent manner. Here, we show that, as a prerequisite for IL-33-induced IL-13 secretion, Th2 cells required the expression of the epidermal growth factor receptor (EGFR) and of its ligand, amphiregulin, for the formation of a signaling complex between T1/ST2 (the IL-33R) and EGFR. This shared signaling complex allowed IL-33 to induce the EGFR-mediated activation of the MAP-kinase signaling pathway and consequently the expression of IL-13. Lack of EGFR expression on T cells abrogated IL-13 expression in infected tissues and impaired host resistance. EGFR expression on Th2 cells was TCR-signaling dependent, and therefore, our data reveal a mechanism by which antigen presentation controls the innate effector function of Th2 cells at the site of inflammation.

Neuroinvasive Nocardia asteroides GUH-2 induces apoptosis in the substantia nigra in vivo and dopaminergic cells in vitro.

Neurodegenerative diseases such as Parkinson's disease are increasingly prevalent in the aging population worldwide. The causes of these disorders are unknown, but many studies have suggested that the etiology is likely multifactorial and may involve exposure to something in the environment combined with the normal aging process. Nocardia asteroides are bacteria commonly found in the soil, and neuroinvasive strains of nocardiae have been described. N. asteroides strain GUH-2 invades the brains of experimentally infected animals and selectively affects dopaminergic neurons of the substantia nigra (SN), causing an L-DOPA-responsive movement disorder resembling parkinsonism. Furthermore, dopaminergic neurons undergo morphological changes characteristic of apoptosis following nocardial infection. Apoptosis has been implicated in dopaminergic neuronal dropout in Parkinson's patients as well as other parkinsonian models. Thus, in this study, in vivo and in vitro models were utilized to measure the ability of GUH-2 to induce the apoptotic death of dopaminergic cells. Following infection with GUH-2, dopaminergic apoptotic cells were identified in the SN of animals by in situ end labeling, which detects DNA fragmentation, combined with fluorescent immunolabeling of tyrosine hydroxylase-positive cells. In addition, apoptosis was observed in PC12 cell cultures incubated with GUH-2 by both in situ end labeling and the annexin V assay, which detects externalization of phosphatidylserine of the plasma membrane, indicating apoptotic death. Based on the results of these studies, it appears that experimental infection with N. asteroides provides a general model for studying apoptosis in parkinsonian disorders.

[Nocardial brain abscess: case report].

A 25-year-old man, who was slightly immunosuppressed, presented headache and right motor weakness due to multiple brain abscesses disseminated from lung abscess. They were diagnosed, by bacteriological examination, as nocardial brain abscesses (nocardia asteroides) 4 weeks after the first operation. In spite of delay in the diagnosis, he was relieved by operations (three times) and chemotherapy including high doses of Sulfamethoxazole-Trimethoprim. He was eventually discharged. We stress the necessity of early diagnosis and the efficacy of Sulfamethoxazole-Trimethoprim for nocardial brain abscess.