Browsing by Author "Croce, Roberta"

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Breaking the Red Limit: Efficient Trapping of Long-Wavelength Excitations in Chlorophyll-f-Containing Photosystem I
(Elsevier BV, 2021-01) Tros, Martijn; Mascoli, Vincenzo; Shen, Gaozhong; Ho, Ming-Yang; Bersanini, Luca; Gisriel, Christopher J.; Bryant, Donald A.; Croce, Roberta
Background: Food insecurity (FI) is an important public health issue for US veterans. For many veterans, civilian life is fraught with service-incurred health issues and socioeconomic challenges, each risk factors for FI. The FI literature on veterans is limited due to insufficient coverage of the topic’s complexity and the methods used to study it in this population. No published analysis has evaluated how FI has been examined in US veterans. Objectives: We assessed how FI has been examined in US military veterans by identifying (1) the major content areas, or domains, studied in association with FI and (2) the existing research gaps. Methods: A scoping literature review was conducted to map the main research domains of the FI literature and identify knowledge gaps. Electronic database and hand searches identified potentially relevant studies (n = 61). Data extraction, utilizing a standardized set of design parameters, was completed. Duplicate removal and application of inclusion/exclusion criteria resulted in the studies (n = 21) selected for critical review. Results: Eight research domains were determined: FI prevalence, health status, dietary practices, health care utilization, economic instability, homelessness/housing instability, food program participation, and community/emergency preparedness—the most dominant was health status and the least dominant were social determinants (ie, homelessness/housing instability, food program participation). Research on validity and usability of FI assessment methods in veterans was virtually absent. Military service factors, longitudinal effects, FI among women, intervention effectiveness, and other areas lacked sufficient inquiry. Conclusion: Research is required on lesser examined content areas and methodology to optimize surveillance and policy for veteran FI.
Harvesting far-red light: Functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002
(2020-08) Tros, Martijn; Bersanini, Luca; Shen, Gaozhong; Ho, Ming-Yang; van Stokkum, Ivo H. M.; Bryant, Donald A.; Croce, Roberta
The heterologous expression of the far-red absorbing chlorophyll (Chl) f in organisms that do not synthesize this pigment has been suggested as a viable solution to expand the solar spectrum that drives oxygenic photosynthesis. In this study, we investigate the functional binding of Chl f to the Photosystem I (PSI) of the cyanobacterium Synechococcus 7002, which has been engineered to express the Chl f synthase gene. By optimizing growth light conditions, one-to-four Chl f pigments were found in the complexes. By using a range of spectroscopic techniques, isolated PSI trimeric complexes were investigated to determine how the insertion of Chl f affects excitation energy transfer and trapping efficiency. The results show that the Chls f are functionally connected to the reaction center of the PSI complex and their presence does not change the overall pigment organization of the complex. Chl f substitutes Chl a (but not the Chl a red forms) while maintaining efficient energy transfer within the PSI complex. At the same time, the introduction of Chl f extends the photosynthetically active radiation of the new hybrid PSI complexes up to 750 nm, which is advantageous in far-red light enriched environments. These conclusions provide insights to engineer the photosynthetic machinery of crops to include Chl f and therefore increase the light-harvesting capability of photosynthesis.