Tribute to Kenneth Sauer (1931-2022): a mentor, a role-model, and an inspiration to all in the field of photosynthesis.

Kenneth (Ken) Sauer was a mainstay of research in photosynthesis at the University of California, Berkeley and the Lawrence Berkeley National Laboratory (LBNL) for more than 50 years. Ken will be remembered by his colleagues, and other workers in the field of photosynthesis as well, for his pioneering work that introduced the physical techniques whose application have enriched our understanding of the basic reactions of oxygenic photosynthesis. His laboratory was a training ground for many students and postdocs who went on to success in the field of photosynthesis and many others.

Dendritic cell-specific deletion of PKCδ in offspring of allergic mothers prevents the predisposition for development of allergic lung inflammation in offspring.

In humans and in mice, maternal allergy predisposes offspring to development of allergy. In murine models, increased levels of maternal β-glucosylceramides are both necessary and sufficient for the development of allergic predisposition in offspring. Furthermore, increased numbers of CD11b+ dendritic cell subsets in the offspring of allergic mothers are associated with allergic predisposition.

Lissajous curves as aerial search patterns.

Manned and unmanned systems are prevalent in a wide range of aerial searching applications. For aircraft whose trajectory is not or cannot be planned on-the-fly, optimal deterministic search pattern generation is a critical area of research. Lissajous curves have recently caught attention as excellent candidates for all kinds of aerial search applications, but little fundamental research has been done to understand how best to design Lissajous pattern (LP)s for this use.

Cryo-EM structure of HQNO-bound alternative complex III from the anoxygenic phototrophic bacterium Chloroflexus aurantiacus.

Alternative complex III (ACIII) couples quinol oxidation and electron acceptor reduction with potential transmembrane proton translocation. It is compositionally and structurally different from the cytochrome bc1/b6f complexes but functionally replaces these enzymes in the photosynthetic and/or respiratory electron transport chains (ETCs) of many bacteria. However, the true compositions and architectures of ACIIIs remain unclear, as do their structural and functional relevance in mediating the ETCs.

Photoacoustic imaging of the dynamics of a dye-labeled IgG4 monoclonal antibody in subcutaneous tissue reveals a transient decrease in murine blood oxygenation under anesthesia.

Significance: Over 100 monoclonal antibodies have been approved by the U.S. Food and Drug Administration (FDA) for clinical use; however, a paucity of knowledge exists regarding the injection site behavior of these formulated therapeutics, particularly the effect of antibody, formulation, and tissue at the injection site.

A cytochrome c mediates the cyclic electron transport chain of the anoxygenic phototrophic bacterium Roseiflexus castenholzii.

Roseiflexus castenholzii is a gram-negative filamentous phototrophic bacterium that carries out anoxygenic photosynthesis through a cyclic electron transport chain (ETC). The ETC is composed of a reaction center (RC)-light-harvesting (LH) complex (rcRC-LH); an alternative complex III (rcACIII), which functionally replaces the cytochrome bc/bf complex; and the periplasmic electron acceptor auracyanin (rcAc). Although compositionally and structurally different from the bc/bf complex, rcACIII plays similar essential roles in oxidizing menaquinol and transferring electrons to the rcAc.

Photoacoustic imaging reveals mechanisms of rapid-acting insulin formulations dynamics at the injection site.

Objective: Ultra-rapid insulin formulations control postprandial hyperglycemia; however, inadequate understanding of injection site absorption mechanisms is limiting further advancement. We used photoacoustic imaging to investigate the injection site dynamics of dye-labeled insulin lispro in the Humalog® and Lyumjev® formulations using the murine ear cutaneous model and correlated it with results from unlabeled insulin lispro in pig subcutaneous injection model.

Methods: We employed dual-wavelength optical-resolution photoacoustic microscopy to study the absorption and diffusion of the near-infrared dye-labeled insulin lispro in the Humalog and Lyumjev formulations in mouse ears.

Discovery of Chlorophyll : Isolation and Characterization of a Far-Red Cyanobacterium from the Original Site of Manning and Strain (1943) at Moss Beach, California.

We have isolated a chlorophyll--containing cyanobacterium from the intertidal field site at Moss Beach, on the coast of Central California, USA, where Manning and Strain (1943) originally discovered this far-red chlorophyll. Here, we present the cyanobacterium's environmental description, culturing procedure, pigment composition, ultrastructure, and full genome sequence. Among cultures of far-red cyanobacteria obtained from red algae from the same site, this strain was an epiphyte on a brown macroalgae.

Redox conditions correlated with vibronic coupling modulate quantum beats in photosynthetic pigment-protein complexes.

Quantum coherences, observed as time-dependent beats in ultrafast spectroscopic experiments, arise when light-matter interactions prepare systems in superpositions of states with differing energy and fixed phase across the ensemble. Such coherences have been observed in photosynthetic systems following ultrafast laser excitation, but what these coherences imply about the underlying energy transfer dynamics remains subject to debate. Recent work showed that redox conditions tune vibronic coupling in the Fenna-Matthews-Olson (FMO) pigment-protein complex in green sulfur bacteria, raising the question of whether redox conditions may also affect the long-lived (>100 fs) quantum coherences observed in this complex.

Complete genome of the thermophilic purple sulfur Bacterium Thermochromatium tepidum compared to Allochromatium vinosum and other Chromatiaceae.

The complete genome sequence of the thermophilic purple sulfur bacterium Thermochromatium tepidum strain MC (DSM 3771) is described and contrasted with that of its mesophilic relative Allochromatium vinosum strain D (DSM 180) and other Chromatiaceae. The Tch. tepidum genome is a single circular chromosome of 2,958,290 base pairs with no plasmids and is substantially smaller than the genome of Alc.

Martin David Kamen (1913-2002): discoverer of carbon 14, and of new cytochromes in photosynthetic bacteria.

Martin Kamen was a giant of twentieth century science. Trained as a physical chemist, he was the co-discoverer of radioactive Carbon 14, which has transformed many areas of science as a tracer and as a way to date artifacts. He later switched to the study of metabolism and biochemistry and made important contributions to the understanding of nitrogen fixation and photosynthesis.

Structure of cyanobacterial phycobilisome core revealed by structural modeling and chemical cross-linking.

In cyanobacteria and red algae, the structural basis dictating efficient excitation energy transfer from the phycobilisome (PBS) antenna complex to the reaction centers remains unclear. The PBS has several peripheral rods and a central core that binds to the thylakoid membrane, allowing energy coupling with photosystem II (PSII) and PSI. Here, we have combined chemical cross-linking mass spectrometry with homology modeling to propose a tricylindrical cyanobacterial PBS core structure.

Influence of FcRn binding properties on the gastrointestinal absorption and exposure profile of Fc molecules.

The neonatal Fc receptor (FcRn) represents a transport system with the potential to facilitate absorption of biologics across the gastrointestinal barrier. How biologics interact with FcRn to enable their gastrointestinal absorption, and how these interactions might be optimized in a biological therapeutic are not well understood. Thus, we studied the absorption of Fc molecules from the intestine using three IgG-derived Fc variants with different, pH-dependent FcRn binding and release profiles.

Spectropolarimetry of Primitive Phototrophs as Global Surface Biosignatures.

Photosynthesis is an ancient metabolic process that began on early Earth and offers plentiful energy to organisms that can utilize it such that that they achieve global significance. The potential exists for similar processes to operate on habitable exoplanets and result in observable biosignatures. Before the advent of oxygenic photosynthesis, the most primitive phototrophs, anoxygenic phototrophs, dominated surface environments on the planet.

Cryo-EM structures of the air-oxidized and dithionite-reduced photosynthetic alternative complex III from .

Alternative complex III (ACIII) is a multisubunit quinol:electron acceptor oxidoreductase that couples quinol oxidation with transmembrane proton translocation in both the respiratory and photosynthetic electron transport chains of bacteria. The coupling mechanism, however, is poorly understood. Here, we report the cryo-EM structures of air-oxidized and dithionite-reduced ACIII from the photosynthetic bacterium at 3.

Revisiting high-resolution crystal structure of Phormidium rubidum phycocyanin.

The crystal structure of phycocyanin (pr-PC) isolated from Phormidium rubidum A09DM (P. rubidum) is described at a resolution of 1.17 Å.

Analysis of the Complete Genome of the Alkaliphilic and Phototrophic Firmicute Strain HH.

Despite significant interest and past work to elucidate the phylogeny and photochemistry of species of the , genomic analyses of heliobacteria to date have been limited to just one published genome, that of the thermophilic species (.) str. Ice1.

Electronic coherence lifetimes of the Fenna-Matthews-Olson complex and light harvesting complex II.

The study of coherence between excitonic states in naturally occurring photosynthetic systems offers tantalizing prospects of uncovering mechanisms of efficient energy transport. However, experimental evidence of functionally relevant coherences in wild-type proteins has been tentative, leading to uncertainty in their importance at physiological conditions. Here, we extract the electronic coherence lifetime and frequency using a signal subtraction procedure in two model pigment-protein-complexes (PPCs), light harvesting complex II (LH2) and the Fenna-Matthews-Olson complex (FMO), and find that the coherence lifetimes occur at the same timescale (<100 fs) as energy transport between states at the energy level difference equal to the coherence energy.

Binding of red form of Orange Carotenoid Protein (OCP) to phycobilisome is not sufficient for quenching.

The Orange Carotenoid Protein (OCP) is responsible for photoprotection in many cyanobacteria. Absorption of blue light drives the conversion of the orange, inactive form (OCP) to the red, active form (OCP). Concomitantly, the N-terminal domain (NTD) and the C-terminal domain (CTD) of OCP separate, which ultimately leads to the formation of a quenched OCP-PBS complex.