New to Kazakhstan species of zygomycetes in forest soil of Trans-Ili Alatau and Kungey Alatau

This article provides data on two species of soil zygomycetes, new to Kazakhstan, found in the rhizosphere of various woody plants in the Trans-Ili and Kungey Alatau (Northern Tien Shan) – Piptocephalis cylindrospora and Lichtheimia corymbifera. P. cylindrospora is an obligate parasite of zygomycetous fungi; in the study area, it was found twice in Kungey Alatau on species Absidia spinosa and Lichtheimia corymbifera in the rhizosphere of Populus tremula. It does not cause a noticeable deterioration in the development of the host. Earlier, in Kazakhstan, only Piptocephalis arrhiza was registered in the rhizosphere of Armeniaca vulgaris, Populus tremula, Picea schrenkiana, Juniperus spp. Lichtheimia corymbifera, previously belonging to the genus Absidia, was recorded in the rhizosphere of Populus tremula in Kungey Alatau and in the rhizosphere of Picea schrenkiana, Salix sp., Crataegus sp. in Trans-Ili Alatau. L. corymbifera is characterized by heights of 1677 m in Kungey Alatau, and from 1516 to 2007 m a. s. l. in Trans-Ili Alatau. Until recently, in Kazakhstan, only a closely related species Absidia spinosa was isolated from the rhizosphere of Malus sieversii, Armeniaca vulgaris, Crataegus spp., Pinus sylvestris, Populus spp., Sorbus tianschanica, Picea schrenkiana, Salix spp. Descriptions of species colonies based on isolated pure cultures, morphological data, information on ecology and distribution are offered. In L. corymbiferacultures, the so-called “self-parasitism” is observed, in which the fungal hyphae colonize sporangiophores, and the latter look like penetrated by hyphae. The sexual stage of both species was not found in our studies.

Mycobiome and Cancer: What Is the Evidence?

Background: To date, most researchhas focused on the bacterial composition of the human microbiota. In this review, we synopsize recent data on the human mycobiome and cancer, highlighting specific cancer types based on current available evidence, presenting interesting perspectives and limitations of studies and laboratory methodologies. Recent findings: Head and neck cancer carcinoma (HNCC), colorectal carcinoma (CRC) and pancreatic ductal adenocarcinoma (PDA) have been associated with dissimilarities in the composition of mycobiota between cancer cases and non-cancer participants. Overall, fungal dysbiosis with decreased fungal richness and diversity was common in cancer patients; however, a specific mycobiotic signature in HNSCC or CRC has not emerged. Different strains of Candida albicans have been identified among cases with HNCC, whilst Lichtheimia corymbifera, a member of the Mucoraceae family, has been shown to predominate among patients with oral tongue cancer. Virulence factors of Candida spp. include the formation of biofilm and filamentation, and the secretion of toxins and metabolites. CRC patients present a dysregulated ratio of Basidiomycota/Ascomycota. Abundance of Malassezia has been linked to the occurrence and progression of CRC and PDA, particularly in animal models of PDA. Interestingly, Schizophyllum, a component of the oral mycobiome, may exhibit anti-cancer potential. Conclusion: The human mycobiome, per se, along with its interactions with the human bacteriome and the host, may be implicated in the promotion and progression of carcinogenesis. Fungi may be used as diagnostic and prognostic/predictive tools or treatment targets for cancer in the coming years. More large-scale, prospective, multicentric and longitudinal studies with an integrative multi-omics methodology are required to examine the precise contribution of the mycobiome in the etiopathogenesis of cancer, and to delineate whether changes that occur in the mycobiome are causal or consequent of cancer.

Corticosteroids alter alveolar macrophage control of Lichtheimia corymbifera spores in an ex vivo mouse model

Alveolar macrophages (AM) are the first-line lung defense against Mucorales in pulmonary mucormycosis. Since corticosteroid use is a known risk factor for mucormycosis, the aim of this study was to describe the role of corticosteroids on AM capacities to control Lichtheimia corymbifera spore growth using a new ex vivo model. An in vivo mouse model was developed to determine the acetate cortisone dose able to trigger pulmonary invasive infection. Then, in the ex vivo model, male BALB/c mice were pretreated with the corticosteroid regimen triggering invasive infection, before AM collection through bronchoalveolar lavage. AMs from corticosteroid-treated mice and untreated control AMs were then exposed to L. corymbifera spores in vitro (ratio 1:5). AM control of fungal growth, adherence/phagocytosis, and oxidative burst were assessed using optical densities by spectrophotometer, flow cytometry, and 2', 7'-dichlorofluoresceine diacetate fluorescence, respectively. Cortisone acetate at 500 mg/kg, at D-3 and at D0, led to pulmonary invasive infection at D3. Co-incubated spores and AMs from corticosteroid-treated mice had significantly higher absorbance (fungal growth) than co-incubated spores and control AMs, at 24 h (P = .025), 36 h (P = .004), and 48 h (P = .001). Colocalization of spores with AMs from corticosteroid-treated mice was significantly lower than for control AMs (7.6 ± 1.9% vs 22.3 ± 5.8%; P = .003), reflecting spore adherence and phagocytosis inhibition. Finally, oxidative burst was significantly increased when control AMs were incubated with spores (P = 0.029), while corticosteroids hampered oxidative burst from treated AMs (P = 0.321). Corticosteroids enhanced fungal growth of L. corymbifera through AM phagocytosis inhibition and burst oxidative decrease in our ex vivo model. Lay Summary The aim of this study was to describe the impact of corticosteroids on alveolar macrophage (AM) capacities to control Mucorales growth in a new murine ex vivo model. Corticosteroids enhanced fungal growth of L. corymbifera through AM phagocytosis inhibition and burst oxidative decrease.

The diagnostic pitfalls of mucormycosis

Background Invasive mucormycosis is a very aggressive fungal disease among immunocompromised pediatric patients caused by saprophytic fungi that belong to the order of the Mucorales. Case Report We describe a case of of Lichtheimia corymbifera infection in a 15-year-old child with B-cell Non-Hodgkin Lymphoma (NHL) involving lung, kidney and thyroid that initially was diagnosed as probable aspergillosis delaying the effective therapy for mucormycosis. Conclusions This case showed that also intensive chemotherapy with rituximab may represent a risk factor for mucormycosis infection. Liposomal amphotericin B and surgery remain key tools for a successful treatment of this aggressive disease.