Maternal immunization with actinomycetales immunomodulators reduces parasitemias in offspring challenged with Trypanosoma cruzi

Bioactivities and Extract Dereplication of Actinomycetales Isolated From Marine Sponges

In the beginning of the twenty-first century, humanity faces great challenges regarding diseases and health-related quality of life. A drastic rise in bacterial antibiotic resistance, in the number of cancer patients, in the obesity epidemics and in chronic diseases due to life expectation extension are some of these challenges. The discovery of novel therapeutics is fundamental and it may come from underexplored environments, like marine habitats, and microbial origin. Actinobacteria are well-known as treasure chests for the discovery of novel natural compounds. In this study, eighteen Actinomycetales isolated from marine sponges of three Erylus genera collected in Portuguese waters were tested for bioactivities with the main goal of isolating and characterizing the responsible bioactive metabolites. The screening comprehended antimicrobial, anti-fungal, anti-parasitic, anti-cancer and anti-obesity properties. Fermentations of the selected strains were prepared using ten different culturing media. Several bioactivities against the fungus Aspergillus fumigatus, the bacteria Staphylococcus aureus methicillin-resistant (MRSA) and the human liver cancer cell line HepG2 were obtained in small volume cultures. Screening in higher volumes showed consistent anti-fungal activity by strain Dermacoccus sp. #91-17 and Micrococcus luteus Berg02-26. Gordonia sp. Berg02-22.2 showed anti-parasitic (Trypanosoma cruzi) and anti-cancer activity against several cell lines (melanoma A2058, liver HepG2, colon HT29, breast MCF7 and pancreatic MiaPaca). For the anti-obesity assay, Microbacterium foliorum #91-29 and #91-40 induced lipid reduction on the larvae of zebrafish (Danio rerio). Dereplication of the extracts from several bacteria showed the existence of a variety of secondary metabolites, with some undiscovered molecules. This work showed that Actinomycetales are indeed good candidates for drug discovery.

An insight into the ecology, diversity and adaptations of Gordonia species

The bacterial genus Gordonia encompasses a variety of versatile species that have been isolated from a multitude of environments. Gordonia was described as a genus about 20 years ago, and to date, 39 different species have been identified. Gordonia is recognized for symbiotic associations with multiple hosts, including aquatic (marine and fresh water) biological forms and terrestrial invertebrates. Some Gordonia species isolated from clinical specimens are known to be opportunistic human pathogens causing secondary infections in immunocompromised and immunosuppressive individuals. They are also predominant in mangrove ecosystems and terrestrial sites. Members of the genus Gordonia are ecologically adaptable and show marked variations in their properties and products. They generate diverse bioactive compounds and produce a variety of extracellular enzymes. In addition, production of surface active compounds and carotenoid pigments allows this group of microorganisms to grow under different conditions. Several isolates from water and soil have been implicated in bioremediation of different environments and plant associated species have been explored for agricultural applications. This review highlights the prevalence of the members of this versatile genus in diverse environments, details its associations with living forms, summarizes the biotechnologically relevant products that can be obtained and discusses the salient genomic features that allow this Actinomycete to survive in different ecological niches.

Modulation of immune response in experimental Chagas disease

Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas disease, affects nearly 18 million people in Latin America and 90 million are at risk of infection. The parasite presents two stages of medical importance in the host, the amastigote, intracellular replicating form, and the extracellular trypomastigote, the infective form. Thus infection by T. cruzi induces a complex immune response that involves effectors and regulatory mechanisms. That is why control of the infection requires a strong humoral and cellular immune response; hence, the outcome of host-parasite interaction in the early stages of infection is extremely important. A critical event during this period of the infection is innate immune response, in which the macrophage’s role is vital. Thus, after being phagocytized, the parasite is able to develop intracellularly; however, during later periods, these cells induce its elimination by means of toxic metabolites. In turn, as the infection progresses, adaptive immune response mechanisms are triggered through the TH1 and TH2 responses. Finally, T. cruzi, like other protozoa such as Leishmania and Toxoplasma, have numerous evasive mechanisms to the immune response that make it possible to spread around the host. In our Laboratory we have developed a vaccination model in mice with Trypanosoma rangeli, nonpathogenic to humans, which modulates the immune response to infection by T. cruzi, thus protecting them. Vaccinated animals showed an important innate response (modulation of NO and other metabolites, cytokines, activation of macrophages), a strong adaptive cellular response and significant increase in specific antibodies. The modulation caused early elimination of the parasites, low parasitaemia, the absence of histological lesions and high survival rates. Even though progress has been made in the knowledge of some of these mechanisms, new studies must be conducted which could target further prophylactic and therapeutic trials against T. cruzi infection.

Beneficial effects of immunotherapy with extracts derived from Actinomycetales on rats with spontaneous obesity and diabetes

AIMS

To determine whether immunotherapy with heat-killed, selected Actinomycetales species could influence the progression of spontaneous Type 2 diabetes mellitus and obesity in a rat model.

MATERIALS & METHODS

Preparations of either Gordonia bronchialis, Tsukamurella inchonensis or a saline placebo were given by three subcutaneous injections, 30 days apart, starting when rats were aged 120 days, just before development of Type 2 diabetes mellitus, and at day 440, when the disease was well established. Bodyweight, blood sugar, cholesterol, triglycerides and insulin levels were measured to determine the effects and at the end of the experiments, animals were subjected to necropsy.

RESULTS

The development of Type 2 diabetes mellitus was prevented by both reagents, most effectively by T. inchonensis. In the treatment experiment, the effects of the disease were reduced by both treatments, markedly so by T. inchonensis. In both experiments obesity was reduced in treated animals. The possible mechanisms of action are discussed.

CONCLUSION

Our findings suggest that Type 2 diabetes mellitus in the studied rats is associated with obesity, and that both diabetes and obesity can be prevented or improved by treatment with Actinomycetales immune modulators.