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The involvement of the second pair of chlorophylls, termed A -1A and A -1B , in light-induced electron transfer in photosystem I (PSI) is currently debated. Asparagines at PsaA600 and PsaB582 are involved in coordinating the A -1B and A -1A pigments, respectively. Here we have mutated these asparagine residues to methionine in two single mutants and a double mutant in PSI from Synechocystis sp. PCC 6803, which we term NA600M, NB582M, and NA600M/NB582M mutants. (P700 + -P700) FTIR difference spectra (DS) at 293 K were obtained for the wild-type and the three mutant PSI samples. The wild-type and mutant FTIR DS differ considerably. This difference indicates that the observed changes in the (P700 + -P700) FTIR DS cannot be due to only the P A and P B pigments of P700. Comparison of the wild-type and mutant FTIR DS allows the assignment of different features to both A -1 pigments in the FTIR DS for wild-type PSI and assesses how these features shift upon cation formation and upon mutation. While the exact role the A -1 pigments play in the species we call P700 is unclear, we demonstrate that the vibrational modes of the A -1A and A -1B pigments are modified upon P700 + formation. Previously, we showed that the A -1 pigments contribute to P700 in green algae. In this manuscript, we demonstrate that this is also the case in cyanobacterial PSI. The nature of the mutation-induced changes in algal and cyanobacterial PSI is similar and can be considered within the same framework, suggesting a universality in the nature of P700 in different photosynthetic organisms.

Objectively measuring physical activity (PA) has consistently shown an association with reduced all-cause mortality risk in cross-sectional studies. However, the strength of this association may change over time. We quantify the time-varying, covariate-adjusted association between the total volume of PA and all-cause mortality over a 12-year follow-up period using Cox regression with a time varying effect of population-referenced quantile total activity count adjusted for traditional risk factors. Analyses focus on participants 50-84 years old with adequate accelerometer wear time and without missing covariates. The findings suggest that (1) the use of baseline PA in Cox models with long follow-up periods may be inappropriate without time-varying effects and (2) the use of accelerometry derived volume of PA in risk score calculations may be most appropriate for short-term to medium-term risk scores., Competing Interests: Competing interests: CC is consulting with Bayer and Johnson and Johnson on methods development for wearable devices in clinical trials. The details of the contracts are disclosed through the Johns Hopkins University eDisclose system and have no direct or apparent relationship with this manuscript., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Being sessile, plants encounter various biotic and abiotic threats in their life cycle. To minimize the damages caused by such threats, plants have acquired sophisticated response mechanisms. One major such response includes memorizing the encountered stimuli in the form of a metabolite, hormone, protein, or epigenetic marks. All of these individually as well as together, facilitate effective transcriptional and post-transcriptional responses upon encountering the stress episode for a second time during the life cycle and in some instances even in the future generations. This review attempts to highlight the recent advances in the area of plant memory. A detailed understanding of plant memory has the potential to offer solutions for developing climate-resilient crops for sustainable agriculture., Competing Interests: Declaration of Competing Interest No conflict of interest declared., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Microsecond time-resolved step-scan FTIR difference spectroscopy was used to study photosystem I (PSI) from Thermosynechococcus vestitus BP-1 (T. vestitus, formerly known as T. elongatus) at 77 K. In addition, photoaccumulated (P700 + -P700) FTIR difference spectra were obtained at both 77 and 293 K. The FTIR difference spectra are presented here for the first time. To extend upon these FTIR studies nanosecond time-resolved infrared difference spectroscopy was also used to study PSI from T. vestitus at 296 K. Nanosecond infrared spectroscopy has never been used to study PSI samples at physiological temperatures, and here it is shown that such an approach has great value as it allows a direct probe of electron transfer down both branches in PSI. In PSI at 296 K, the infrared flash-induced absorption changes indicate electron transfer down the B- and A-branches is characterized by time constants of 33 and 364 ns, respectively, in good agreement with visible spectroscopy studies. These time constants are associated with forward electron transfer from A 1 - to F X on the B- and A-branches, respectively. At several infrared wavelengths flash-induced absorption changes at 296 K recover in tens to hundreds of milliseconds. The dominant decay phase is characterized by a lifetime of 128 ms. These millisecond changes are assigned to radical pair recombination reactions, with the changes being associated primarily with P700 + rereduction. This conclusion follows from the observation that the millisecond infrared spectrum is very similar to the photoaccumulated (P700 + -P700) FTIR difference spectrum., (© 2023. The Author(s).)

Introduction During the COVID-19 pandemic, self-medication (SM) has become a critical element in the healthcare system. SM can ease the burden on hospitals and medical resources by treating minor illnesses. However, inappropriate SM practices can lead to adverse drug reactions, drug resistance, and incorrect diagnoses, resulting in poor health outcomes. Methods To evaluate the prevalence, knowledge, causes, and practices of SM among the Bangladeshi population during the COVID-19 outbreak, a cross-sectional survey with structured questionnaires was conducted in Chittagong City, Bangladesh, from March to May 2022. The survey included 265 participants, with an average age of 35.09 years, and a multiple-choice questionnaire was used to gather information. Results The study found that 64.15% of the respondents had sufficient knowledge of SM, while 35.8% had insufficient knowledge. The primary reasons for SM during the pandemic were the influence of friends/family (90.74%), fear of infection or contact with COVID-19 cases (73.15%), and fear of quarantine or self-isolation (72.22%). Analgesics/pain relievers (84%) were the most commonly used drugs for SM for COVID-19 prevention and treatment. Antiulcerants/antacid (42%), vitamin C and multivitamins (42%), and antibiotics (32%) were also frequently used. Conclusion This study suggests that SM is prevalent among Chittagong City residents, particularly those with less than a tertiary education. The study highlights the importance of building awareness about SM practices and taking necessary steps to control them., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Trisha et al.)