Effect of environmental factors on the composition of lipopolysaccharides released from the Rhodobacter capsulatus cell wall

Monocyte activation test (MAT) as an ethical alternative to animal testing

Ethical considerations surrounding the utilization of animals in scientific research have prompted a widespread search for alternative methodologies. This review explores the historical context and ethical dilemmas associated with traditional animal testing methods, before introducing the Monocyte Activation Test (MAT) as a promising alternative, and outlining its basic principles, historical development, and advantages over conventional animal testing. The role of monocytes in the immune system and the activation pathways utilized in MAT are elucidated, while regulatory acceptance and guidelines for MAT validation are introduced, alongside case studies proving its reliability and reproducibility. The applications of MAT in pharmaceutical and medical device testing are summarized, together with its potential future uses. Although the MAT faces limitations and challenges, the global perspective to reduce unnecessary animal tests has become a general concept in animal welfare and scientific research. [BMB Reports 2025; 58(3): 105-115].

An unexpectedly branched biosynthetic pathway for bacteriochlorophyll b capable of absorbing near-infrared light

Chlorophyllous pigments are essential for photosynthesis. Bacteriochlorophyll (BChl) b has the characteristic C8-ethylidene group and therefore is the sole naturally occurring pigment having an absorption maximum at near-infrared light wavelength. Here we report that chlorophyllide a oxidoreductase (COR), a nitrogenase-like enzyme, showed distinct substrate recognition and catalytic reaction between BChl a- and b-producing proteobacteria. COR from BChl b-producing Blastochloris viridis synthesized the C8-ethylidene group from 8-vinyl-chlorophyllide a. In contrast, despite the highly conserved primary structures, COR from BChl a-producing Rhodobacter capsulatus catalyzes the C8-vinyl reduction as well as the previously known reaction of the C7 = C8 double bond reduction on 8-vinyl-chlorophyllide a. The present data indicate that the plasticity of the nitrogenase-like enzyme caused the branched pathways of BChls a and b biosynthesis, ultimately leading to ecologically different niches of BChl a- and b-based photosynthesis differentiated by more than 150 nm wavelength.