Recent human and animal studies have found associations between gut microbiota composition and serum levels of sex hormones, indicating that they could be an important factor in shaping the microbiota. However, little is known about the effect of regular hormonal fluctuations over the menstrual cycle or CHC-related changes of hormone levels on gut microbiota structure, diversity and dynamics. The aim of this study was to investigate the effect of CHCs on human gut microbiota composition. The effect of CHC pill intake on gut microbiota composition was studied in a group of seven healthy pre-menopausal women using the CHC pill, compared to the control group of nine age-matched healthy women that have not used hormonal contraceptives in the 6 months prior to the start of the study. By analysing the gut microbiota composition in both groups during one menstrual cycle, we found that CHC usage is associated with a minor decrease in gut microbiota diversity and differences in the abundance of several bacterial taxa. These results call for further investigation of the mechanisms underlying hormonal and hormonal contraceptive-related changes of the gut microbiota and the potential implications of these changes for women's health.

Alterations in the human microbiome have been linked to several malignant diseases. Here, we investigated the oral microbiome of 79 patients with relapsed/refractory multiple myeloma (MM) treated with ixazomib-thalidomide-dexamethasone. Increased alpha diversity (Shannon index) at the phylum level was associated with longer progression-free survival (PFS) (10.2 vs 8.5 months, P = .04), particularly in patients with very long (>75% quartile) PFS . Additionally, alpha diversity was lower in patients with progressive disease (P < .05). These findings suggest an interrelationship between the oral microbiome and outcome in patients with MM and encourage a novel direction for diagnostic and/or therapeutic strategies.

Almost all land plants deliver recently assimilated carbon to mycorrhizal fungi, and receive nutrients in return. The controls of this exchange are, however, not yet fully understood. Here, we investigated if carbon for nitrogen exchange in the ectomycorrhizal symbiosis of Fagus sylvatica is regulated based on reciprocal rewards, and at which spatial scales such a reward mechanism operates.

We set up a two-source tracing experiment with young ectomycorrhizal beech trees. We analysed the short-time distribution of isotopically labelled recent photosynthates (13CO2) and fungi-delivered nitrogen (15N) across the root system, as well as at the microscopic, cellular scale within an individual mycorrhizal root tip.

While plants showed only limited control on directing photosynthates towards roots associated with N-delivering fungi, nano-scale secondary ion mass spectrometry (NanoSIMS) analysis of an individual ectomycorrhizal root tip revealed a strong spatial correlation between the distribution of plant-fixed C and fungi-delivered nitrogen. 

Our results provide first evidence for a reciprocal exchange of C for N between plants and ectomycorrhizal fungi operating at the cellular scale in the ectomycorrhizal tissue. That suggests that individual hyphae emanating from a root tip, that are actively foraging for nutrients may be specifically supported by a greater share of recent photosynthates.