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Biological samples such as tissues, blood, or tumors are often complex and harbor heterogeneous populations of cells. Separating out specific cell types or subpopulations from such complex mixtures to study their metabolic phenotypes is challenging because experimental procedures for separation may disturb the metabolic state of cells. To address this issue, we developed a method for analysis of cell subpopulations using stable isotope tracing and fluorescence-activated cell sorting followed by liquid chromatography-high-resolution mass spectrometry. To ensure a faithful representation of cellular metabolism after cell sorting, we benchmarked sorted extraction against direct extraction. While peak areas differed markedly with lower signal for amino acids but higher signal for nucleotides, mass isotopomer distributions from sorted cells were generally in good agreement with those obtained from direct extractions, indicating that they reflect the true metabolic state of cells prior to sorting. In proof-of-principle studies, our method revealed metabolic phenotypes specific to T cell subtypes, and also metabolic features of cells in the committed phase of the cell division cycle. Our approach enables studies of a wide range of adherent and suspension cell subpopulations, which we anticipate will be of broad importance in cell biology and biomedicine.

Folate metabolism is central to cell proliferation and a target of commonly used cancer chemotherapeutics. In particular, the mitochondrial folate-coupled metabolism is thought to be important for proliferating cancer cells. The enzyme MTHFD2 in this pathway is highly expressed in human tumors and broadly required for survival of cancer cells. Although the enzymatic activity of the MTHFD2 protein is well understood, little is known about its larger role in cancer cell biology. We here report that MTHFD2 is co-expressed with two distinct gene sets, representing amino acid metabolism and cell proliferation, respectively. Consistent with a role for MTHFD2 in cell proliferation, MTHFD2 expression was repressed in cells rendered quiescent by deprivation of growth signals (serum) and rapidly re-induced by serum stimulation. Overexpression of MTHFD2 alone was sufficient to promote cell proliferation independent of its dehydrogenase activity, even during growth restriction. In addition to its known mitochondrial localization, we found MTHFD2 to have a nuclear localization and co-localize with DNA replication sites. These findings suggest a previously unknown role for MTHFD2 in cancer cell proliferation, adding to its known function in mitochondrial folate metabolism.

This paper brings together two separate fields—inclusion and alternative organizations—to study the relational aspects of inclusion and exclusion both within and beyond organizations. By analyzing reports and websites of organizations committed to the network "Economy for the Common Good," we empirically explore, first, how these organizations represent their "alternativeness" and how this relates to inclusion and exclusion; and second, we address the question of who is included in these alternative ventures by examining both their inclusionary and exclusionary potential in terms of diversity. Introducing a conceptual framework to distinguish between internal and external perspectives on inclusion and exclusion, our qualitative analysis reveals the simultaneity of two contradictory phenomena: On the one hand, these alternative organizations offer a new inclusionary potential that encompasses both the social and natural environments; on the other, they tend to ignore internal and external inclusion along diversity dimensions. Hence, we conclude that while there exists the potential to link inclusion with alternative organizations, a commitment to an alternative economy does not automatically lead to an engagement with issues of diversity and inclusion. [ABSTRACT FROM AUTHOR]

The Bacillus subtilis GroES and GroEL proteins are molecular chaperonins which exhibit high sequence homologies to the corresponding proteins in Escherichia coli. An investigation was conducted to clone, sequence, map and analyze the expression of the B. subtilis groES and GroEL genes. Northern blot analysis showed that heat shock conditions induced the expression of two transcripts corresponding to the coding region of groES and groEL. The genes were mapped to 342 degrees of the B. subtilis genomic map. The analysis also identified an inverted repeat sequence within the 5' leader sequence which may be involved in groESL regulation.