The high nitrogen content of the Atacama Desert sample reflects the high nitrate content of these surface soils while the South Bay sample showed elevated levels of TOC, 1.01 mg·N/g.The organic C/N ratios in the ancient gypsum and anhydrite samples ranged from 12 – 41, indicating that the major organic component present in these sulfates is likely a humic acid/kerogen-like material , a conclusion that is consistent with the depleted carbon and nitrogen isotopic values associated with organic material. The exceptions are the Atacama Desert Sample, C/N ~ 1.2, and the South Bay gypsum with a C/N ratio of ~7. These numbers are more indicative of recent biological material, however the Atacama result is skewed because of the high nitrate content. The detected levels of amino acids and their enantiomers, as well as methylamine and ethylamine , the decarboxylation products of glycine and alanine, on average account for ~0.04 % of the total organic carbon and ~0.17 % of the total organic nitrogen for the six samples . Even though amino acids and amines constitute only a fraction of the total organic carbon and nitrogen present in the sulfate minerals , they are readily detected and characterized .The majority of organic matter detected in these sulfate minerals is likely ancient organic matter trapped within the matrix, along with a minor component derived from the remnants of more recent sulfate-reducing microbial communities.
The presence of the D-enantiomers of several amino acids in the gypsum samples suggest that these compounds are mostly original components of the depositional environment and not recent contaminants, however in the case of alanine,hydroponic channel their presence could partially be due to bacterial cell wall material. The correlation between the ratios of the amino acids glycine and alanine and their degradation products, methylamine and ethylamine respectively, also suggests the organic material is a component of the original evaporite. Amines are not typically detected in ancient terrestrial carbonate minerals , presumably because they are volatile and lost from the mineral matrices because they tend to form in alkaline environments. However, they appear to be retained in sulfate minerals, perhaps as their non-volatile sulfate salts. The amino acids should be racemic in the ancient samples because they have ages in excess of several million years , but this was found not to be the case in all of the samples. The Anza-Borrego gypsum is the only sample in which the D/L alanine ratio is close to unity and this sample therefore appears to be the most pristine. Anza-Borrego also has no detectable adenine, so these amino acids appear to be from extinct life as ancient bio-signature. The ratio Z, the concentrations of methylamine divided by the concentrations of glycine and the concentration of ethylamine divided by the concentrations of alanine can be used as a diagenetic indicator for these samples. The Z-ratios for these two degradation systems are shown in Equations 3.1 and 3.2.Equation 3.5 was used to estimate the rates of decarboxylation in gypsum from the various sample localities and these values were used to calculate the half lives for glycine and alanine decarboxylation . The calculated kinetic decarboxylation rate constants and half-lives are shown in Table 3.3 for all of the samples, along with the estimated average exposure temperatures.
The Atacama Desert is assumed to have been climatically stable for the past 2 Ma , so its average exposure temperature is assumed to be ~20°C. At the Anza-Borrego site, present average temperatures are ~23°C although average temperatures over the last 5 million years have likely been somewhat cooler especially during Pleistocene ice ages. The temperature of the Red Sea sediment sample was estimated to have ranged from the present day bottom water temperatures of 22°C to ~48°C at 230 m depth where the sample was obtained . Although, the present temperatures at Haughton Crater are very cold , when the crater and sulfate minerals were formed there was an extended period of high temperature hydrothermal activity . Even 2-3 Ma, temperatures in this region were likely significantly warmer than today , so the average exposure temperature is assumed to be 0°C. The modern Panoche Valley average temperature is ~17°C, but over the past 40 Ma depositional history of the region, the average exposure temperature was likely higher . Using these estimated average exposure temperatures, the calculated kinetic decarboxylation rate constants and half-lives were calculated .Temperatures on Mars over the last 4 billion years are considered to be similar to the cold that prevail today . If the surface paleotemperature on Mars has averaged 0°C, then t1/2 for decarboxylation of glycine in gypsum is estimated to be ~4 x 108 years based on the Atacama Desert data, ~3 x 108 years for the Anza-Borrego results, and ~5 x 108 using the Panoche sample. The Haughton Crater sample indicates significantly faster kinetics with a half-life at 0°C of ~5 x 106 years. The alanine decarboxylation system yields kinetic halflives approximately one order of magnitude greater in all samples, ~5 x 109 years , in accord with previous studies . If the surface temperature on Mars has averaged –20°C, then the calculated glycine and alanine decarboxylation t1/2 values would be much longer, resulting in much greater preservation over billion-year timescales. The apparently shorter half-lives predicted using the Haughton Crater gypsum may be explained by its exposure to either a warmer climate over its history, hydrothermal conditions after deposition, or this maybe the result of more recent amino acid contamination diluting the Z-values.
Because of the pristine nature of the Anza-Borrego gypsum, the t1/2 values based on this sample are considered the most accurate, although the results from the Atacama Desert, Red Sea, and Panoche Valley agree well with these results. These calculations imply that at modern Martian surface temperatures, amino acids in gypsum should be preserved for periods in excess of several billion years. The estimated decarboxylation rates in sulfate minerals on Mars are so slow that the limiting factor in the survival of amino acids is likely to be radiolysis in the upper 1-2 meters of the regolith by galactic cosmic radiation and UV-induced or metal-catalyzed oxidation . The Martian iron-oxide rich soils may provide a barrier against cosmic radiation, and organic material preservation may be increased at greater depths in the regolith. If jarosite is present at these locations, then its high iron content might assist preservation by offering further shielding against radiolysis. While pure crystalline gypsum is transparent to visible and UV light , impure Antarctic gypsum crusts are essentially opaque to radiation below 400 nm , and a few millimeters of a similar mineral on Mars should be able to shield gypsum from UV penetration. In the absence of UV-light, the contribution of metal-catalyzed oxidation should be minimal. Therefore, amino acids and other organic compounds should be extremely persistent in sulfate minerals at the low temperatures on Mars.Over the last few decades, the field of nutrition has grown and evolved. Although we continue to define the critical roles that nutrients play as fuel sources, enzyme cofactors, signaling molecules, and vital infrastructure for our bodies, the cutting edge of nutrition research is pushing beyond simply meeting our bodies’ basic needs. Indeed,hydroponic dutch buckets as the population is living longer, an emerging focus for nutrition has been on obtaining and maintaining optimal health over the life course. On 10 October, 2022, the Council for Responsible Nutrition held their annual Science in Session conference entitled Optimizing Health through Nutrition – Opportunities and Challenges. The audience consisted of scientists and executives from dietary supplement and functional food companies as well as nutrition graduate student awardees of a CRN and ASN Foundation educational scholarship to attend the symposium. The goals for this meeting were to propose a definition for optimal nutrition and identify strategies and tools for evaluating optimal health and nutrition outcomes while highlighting the gaps in this emerging space. Now more than ever in history, our population’s health has emerged as a global priority. Currently, 6 in 10 adults in the United States have a chronic disease, and 4 in 10 have 2 or more. In <10 y, the number of older adults is projected to increase by ~18 million. This means that by 2030, 1 in 5 Americans is projected to be 65 y old. As the major risk factor for many chronic illnesses is age, it is anticipated that the rates of all age-related diseases, especially chronic diseases, will skyrocket, potentially overwhelming the health care system. We need to enable the health care system—and the population—to be more proactive rather than reactive toward health outcomes.
There is a critical need to help find solutions to optimize health across the lifespan to support living better longer, i.e., health span. Ensuring optimal nutrition is a significant and easily modifiable variable in the solution for maintaining and improving health span. We need to advance concepts beyond essential health and consider meeting the nutritional needs for optimal health. Although the nutrition science community is moving toward the vision of nutrition to support optimal health, many challenges and gaps still exist, but there are also recent advances and exciting opportunities. The goal of the CRN “Science in Session” workshop was to discuss these challenges, gaps, and opportunities in order to advance the concept of nutrition for optimal health. This review summaries these findings and discussions.The DRIs for individual nutrients, including the Estimated Average Requirement and the RDA, are life stage- and sex specific recommendations for Americans and Canadians. These reference intakes were established in the 1990s by the Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine to prevent deficiency disease and to reduce the risk of chronic diseases. However, incorporating chronic disease endpoints has been extremely challenging, primarily because data are largely lacking. Such end points were used to set the DRIs for only a handful of nutrients. Thus, the current DRIs, including the RDAs that are aimed to cover the nutrient needs of 98% of the population, do not account for the amount of a nutrient that one needs in order to achieve and maintain ‘optimal’ health.The science of resilience is not a new concept—this scientific concept was documented in the literature as early as the 1800s; the terminology entered the biomedical sciences in the mid- 1900s and emerged in the early 2000s as a concept to be interconnected in multiple health domains. The questions dominating its broad use and applicability tend to focus on how to define resilience. In 2019, the Trans-NIH Resilience Working Group was formed with a goal to develop an NIH-wide definition of resilience and to achieve consistency and harmony on the design and reporting of resilience research studies. In 1993, an introductory manuscript to a special issue published on the science of resilience included a quote stating, “resilience is at risk for being viewed as a popularized trend that has not been verified through research and is in danger of losing credibility within the scientific community”. The authors of the manuscript also warned against definitional diversity with respect to measures of resilience and urged researchers to clearly operationalize the defi- nition of resilience in all research reports. Remarkably, this call to action served as a primary aim of the Trans-NIH Resilience Working Group when it was organized >25 y after the 1993 special issue on resilience. One of the first activities of the Trans-NIH Resilience Working Group was to host a workshop, in March 2020, which led to the development of a definition of resilience and a conceptual infographic. The definition was intended to be applicable and useful across multiple domains, and it states that resilience encompasses “A system’s capacity to resist, recover, grow, or adapt in response to a challenge or stressor”. A system can represent different domains, levels, and/or processes. Over time, a system’s response to a challenge might show varied degrees of reactions that likely fluctuate in response to the severity of the challenge, the length of time exposed to the challenge, and/or innate/intrinsic factors. To show applicability of the definition in resilience research studies, the Resilience Research Design Tool was later developed to help improve consistency in resilience research reports and to facilitate harmony with respect to measures of resilience outcomes. One of the goals of the resilience framework is to reframe the way we ask research questions, particularly about nutritional interventions like dietary supplements, so that we can better understand health outcomes that are not based solely on disease end points.