From Grave to Cradle

Life cycle assessment (LCA) is a promising tool in the pursuit of sustainable mining. However, the accounting methodologies used in LCA for abiotic resource depletion still have some shortcomings and need to be improved. In this article a new thermodynamic approach is presented for the evaluation of the depletion of nonfuel minerals. The method is based on quantifying the exergy costs required to replace the extracted minerals with current available technologies, from a completely degraded state in what we term “Thanatia” to the conditions currently found in nature. Thanatia is an estimated reference model of a commercial end of the planet, where all resources have been extracted and dispersed, and all fossil fuels have been burned. Mineral deposits constitute an exergy bonus that nature gives us for free by providing minerals in a concentrated state and not dispersed in the crust. The exergy replacement costs provide a measure of the bonus lost through extraction. This approach allows performing an LCA by including a new stage in the analysis: namely the grave to cradle path. The methodology is explained through the case study of nickel depletion.     

矿物作用下A.ferrooxidans中磁小体相关基因的差异表达

目的:研究氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)中与磁小体形成相关的mpsA、magA、thy和mamB基因分别在黄铁矿、黄铜矿、磁黄铁矿和闪锌矿的作用下的表达差异,寻找有利于磁小体形成的最佳培养矿物能源。方法:测量以不同硫化矿为能源时的菌体生长特性,用实时定量PCR方法研究与磁小体形成相关基因的表达差异。结果:在以磁黄铁矿为能源时,菌的生长量及多数基因的表达量优于其它三种矿,四个基因相对表达量分别为1.15、2.35、1.32、2.68。结论:磁黄铁矿是A.f中磁小体形成的最佳矿物能源。     

地球熔岩管道微生物研究对天体生物学的启示

天体生物学作为与深空探测相结合的交叉学科,旨在从地球极端环境类比、古代生命载体信息发掘和模拟等方面揭示地外行星体是否适合生命生存和繁衍,其中适宜的环境条件是评价所有天体是否宜居的重要条件。近年来在月球和火星等行星表面发现了大量由火山熔岩流形成的熔岩管道,这些巨型管状地下空间具有稳定的温度和防辐射等环境条件,为生物在地外星体上的生存提供了潜在的庇护场所。基于地球熔岩管道的天体生物学的类比研究可以为探索地外生命痕迹提供重要线索,本文综述了现阶段地球熔岩管道内微生物的研究进展、微生物痕量气体代谢在天体生物学研究中的潜力及天体生物学的研究进展,旨在为后续开展地球及地外熔岩管道的天体生物学研究提供思路。     

Health benefits and nutritional properties of nori

A brief review is presented of the properties of nori relevant to health. The dried alga contains large amounts of protein, ash, vitamins and carbohydrate. The levels of taurine (/>- 1.2%) are notable as this compound aids enterohepatic circulation of bile acid, thus preventing gallstone through controlling blood-cholesterol levels. Relatively high levels of eicosapentanoic acid, choline, inositol and other B-group vitamins are regarded as beneficial to health. The occurrence of porphyosins and betaines that prevent respectively, gastric shay ulcers and lower blood-cholesterol levels are particular interest. A sulfated galactan, similar to agar, occurs in relatively large quantities; this is a water-soluble dietary fiber that has important functional activities such as an antiblood coagulant, antihypercholesterolemia and shows antitumor activity. Minerals which occur at relatively high levels in nori include Zn, Cu, Mn and Se.It is concluded that nori is a valuable health food in human diets.     

Iron utilization and liver mineral concentrations in rats fed safflower oil, flaxseed oil, olive oil, or beef tallow in combination with different concentrations of dietary iron

Diets with a higher proportion of polyunsaturated fatty acids (i.e., linoleic acid) have decreased iron absorption and utilization compared with diets containing a higher proportion of the saturated fatty acid stearic acid (e.g., beef tallow). However, less is known regarding the influence of other polyunsaturated or monounsaturated fatty acids, along with higher dietary iron, on iron absorption and utilization. The present study was conducted to compare the effects of dietary fat sources known to vary in (n-3), (n-6), and (n-9) fatty acids on iron utilization and liver mineral concentrations. Male weanling rats were fed a diet containing 10, 35, or 100 μg/g iron in combination with saffower oil, flaxseed oil, olive oil, or beef tallow for 8 wk. Indicators of iron status, iron utilization, and liver iron concentrations were unaffected by an interaction between the fat source and iron concentration. Plasma copper was the only variable affected by an interaction between the fat source and dietary iron. Findings of this study demonstrate that flaxseed oil and olive oil may alter tissue minerals and affect iron utilization. Further studies should be conducted to establish the effect of varying (n-3), (n-6), and (n-9) fatty acids on trace mineral status and iron utilization. Data were presented in part at Experimental Biology 2000 as a poster session. A. D. Shotton and E. A. Droke, Dietary fat and iron modify immune function, FASEB J. 14, A239 (2000).     

Nutritional benefits of crematogaster mimosae ants and acacia drepanolobium gum for patas monkeys and vervets in laikipia,Kenya

Patas monkeys (Erythrocebus patas) are midsized primates that feed extensively on the gum of Acacia drepanolobium and the ants are housed in swollen thorns of this Acacia. Their diet resembles that expected more of smaller bodied primates. Patas monkeys are also more like smaller bodied primates in reproducing at high rates. We sought to better understand the convergence of patas monkeys with smaller bodied primates by comparing their feeding behavior on ants and gum with that of closely related, sympatric vervets (Chlorocebus pygerythrus), and analyzing the nutrient content of the gum of A. drepanolobium and of Crematogaster mimosae, the most common ant species eaten by patas monkeys in Laikipia, Kenya. All occurrences of feeding and moving during focal animal sampling revealed that 1) patas monkeys seek A. drepanolobium gum but vervets avoid it; 2) both species open swollen thorns most often in the morning when antsare less active; 3) patas monkeys continually feed onswollen thorns and gum while moving quickly throughout the day, whereas vervets reduce their consumption of these items and their travel rate at mid‐day, and; 4) vervets eat young swollen thorns at a higher rate than patas monkeys. Patas monkeys are able to spend little time acquiring substantial amounts of energy, protein, and minerals from A. drepanolobium gum and C. mimosae ants each day. These findings, when coupled with evidence of causes of infant and adult female mortality, suggest that reproductive success of female patas monkeys is more immediately affected by illness, disease, interactions between adults and infants, and access to water than by food. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

Comparison of serum iron, total iron binding capacity, ferritin, and percent transferrin saturation in nine species of apparently healthy captive lemurs

Lemurs kept in captivity have been reported to be highly prone to accumulate excessive amounts of iron in tissues (hemosiderosis). Diagnosis of the condition is most commonly made during a postmortem examination because an antemortem diagnosis requires a liver biopsy, a procedure that may not be well tolerated by all animals. The lack of a noninvasive method to evaluate iron status in captive lemurs limits investigators' ability to effectively screen animals for the presence of hemosiderosis, and to detect the condition early when treatment protocols are most effective. This study was conducted in an effort to provide data regarding iron analyte values in healthy captive lemurs of multiple species. The relationship of various iron-related metabolites was evaluated in 177 clinically normal lemurs of nine different species. Serum iron (sI), total iron binding capacity (TIBC), and ferritin concentration were measured directly and the percent transferrin saturation (TS) was calculated. Significant differences in various iron metabolites were observed among several species, suggesting that normal reference values for iron metabolites in lemurs may need to be developed on a species by species basis.     

Analysis of nutrient concentrations in the diet,serum, and urine of giraffe from surveyed North American zoological institutions

The objectives of the present research were to conduct a survey to investigate the health history and feeding practices of giraffe in captivity in North America and to obtain samples of hay, concentrate, browse, urine, and serum to compare across zoos, possible factors relating to the development of urolithiasis. Forty‐one out of 98 institutions contacted responded, representing 218 giraffe. All responding zoos fed concentrate and alfalfa hay was the primary forage. Sixty‐five percent of zoos fed browse and 43 different species of browse were listed. Six zoos reported a history of urolithiasis, seven reported wasting syndrome, and 10 reported sudden death. The median daily amount (as fed) of concentrate and hay offered were 5.45 kg (range of 2.73–9.55 kg) and 6.82 kg (range of 2.53–12.50 kg), respectively. The concentrate:hay ratio of the offered diet ranged from 0.22 to 3.47 with a median value of 0.79. Forty‐three percent of the institutions offered a ratio greater than 1:1. Samples of concentrate and hay (six zoos), serum (five zoos), and urine (seven zoos) were obtained for chemical analyses. Analyzed nutrient content of the consumed diet, measured by weighing feed and orts for three consecutive days, met recommendations for giraffe, but was excessive for crude protein and P. Concentrate:hay and serum P were positively correlated (r=0.72; P<0.05). High dietary P content and a high level of concentrate relative to hay may be contributing factors to urolith formation and warrant further investigation. Zoo Biol 29:457–469, 2010. © 2009 Wiley‐Liss, Inc.     

Nutritional Dimorphism in New Guinea Dioecious Figs

The life history of figs (Ficus, Moraceae) involves pollination by specialized insects and seed dispersal by vertebrate frugivores. This three-way interaction raises the possibility of conflict between pollinators and seed dispersers over fig resources. The conflict might be mediated in dioecious figs by the segregation of inflorescences with specialized male and female sexual functions, termed gall figs and seed figs, on separate trees. In dioecious figs, pollinators are intimately associated with gall figs, whereas vertebrate frugivores prefer seed figs and disperse the seeds they contain. Optimal foraging theory predicts that frugivore preference for ripe seed figs is associated with superior nutritional quality when compared to gall figs. We tested this prediction comparing nutrient and mineral properties of ripe figs in 12 functionally dioecious and two monoecious species from New Guinea. Analyses of variance indicated that gall figs contain more fiber and minerals, whereas seed figs contain significantly more carbohydrates and fat. Fruit bats, the primary dispersers of dioecious figs in New Guinea, prefer carbohydrate-rich diets, and from this perspective, seed figs offer a greater nutritional reward than gall figs. More nondigestible fiber in gall figs than seed figs would appear to discourage frugivory. Parallel differences between ripe gall figs and seed figs occur in each independent dioecious lineage whereas nutritional content in monoecious figs is more similar to seed figs. This suggests that sexual dimorphism in nutritional quality might be adaptive and associated with the maintenance of functional dioecy in figs.     

Decorative Landscaping Rock as a Source for Heavy Metal Contamination,Las Vegas,Nevada

Recent drought coupled with population growth throughout the southwestern United States has increased the demand for water-efficient landscaping alternatives. As a result, xeriscaping has become a popular approach to landscaping in arid climates. Currently, no regulations control the mineralogy of decorative rocks that are used in these applications. Eight public sites were examined in Las Vegas, NV, where green and white salt crusts appeared on recently emplaced decorative rocks. The landscaping rocks, underlying soil, surface salt crusts, irrigation water runoff, and plants were analyzed for mineralogy and/or chemistry. Pyrite and high levels of copper were identified in the decorative rock. Acid-rock drainage caused by pyrite oxidation has concentrated copper in salt efflorescences, and As, Cu, Mo, Pb, and Cr in plant tissues. These metals are not known to occur naturally in Las Vegas Valley soils, and our results indicate that their source is the landscaping aggregate. These highly soluble salt crusts have the potential to contaminate the environment, and increase the risk of human exposure. Additionally, expenses resulting from plant mortality and infrastructure damage due to increased sulfate production are undesirable. This research supports the development of regulations preventing the use of sulfide-bearing rocks in future landscaping applications.