Study of carbon compounds in Apollo 12 and 14 lunar samples

The gases released on DF dissolution of a variety of samples have been studied by gas chromatography and high resolution mass spectrometry. Results on Apollo 12 samples confirm previous observations that CH₄ and C₂H₆ are released as well as CD₄, C₂D₄, C₂D₆ and higher deuterated hydrocarbons. The yields correlate with the total carbon content of the samples and the CH₄ and C₂H₆ released may be regarded as indigenous while the deuterated products result from hydrolysis of carbide material. Dissolutions were also performed on five size fractions of sample 14240,5, ranging from >420 to <37 . The yields of CH₄, CD₄,²⁰Ne and³⁶Ar correlate with the surface area and therefore probably arise from solar wind implantation. Other deuterocarbons released include C₂D₄, C₂D₆, C₃D₆, C₃D₈ and C₄D₁₀. Preliminary pyrolysis results of these size differentiated samples confirmed the presence and surface correlation of the CH₄,²⁰Ne and³⁶Ar. Dissolution of the 14148, 14156 and 14149 trench samples showed that their carbon chemistry and solar wind exposure are very similar to that of the 14240 SESC and Apollo 11 and 12 fines of high carbon content. Other interesting components released from the soil samples by DF include D₂S, DCN and CS₂.This paper is an amplified version of the comments made by Dr Holland during the discussions at the meeting on Lunar Analysis: Significance for Exobiology, held at College Park, Maryland, October 26–28, 1971.     

Terrestrial contamination in Apollo lunar samples

The Apollo lunar samples were seen to offer a unique opportunity in the search for extraterrestrial organic matter without the ambiguity surrounding meteorite analysis due to their unknown contamination histories. The recognition that only a small amount of indigenous organic material was likely to be present in lunar samples combined with the extreme sensitivity of organic analysis methods made it clear that this opportunity could be realized only by carefully controlling the collection, processing, and analysis of the samples in order that they might remain free of significant levels of contamination. The contamination control procedures adopted are described and the analytical evidence obtained throughout the program on potential contamination sources is presented. The organic contaminants actually found in the lunar samples by the various investigators are summarized. It is shown that the program succeeded in providing investigators with samples containing less than 0.1 ppm total contamination.     

Search for biogenic structures and viable organisms in lunar samples: A review

A review of the work on searches for biogenic structures and viable life forms in Apollo 11 and 12 samples shows no evidence for biology in these samples. The total amount of samples examined and the negative results from the variety of systems conducive to growth and metabolic activity make it highly improbable that life will be found in surface samples yet to be tested.     

Distribution and isotopic abundance of biogenic elements in lunar samples

A review of the abundance of six biologically important elements (H, C, N, O. P and S) demonstrates that they are present in trace amounts only in lunar matter analysed to date. To the endogenous lunar content, elements are contributed by solar wind irradiation and meteorite impacts. However, it is not yet possible to determine the relative importance of the three sources. Enrichment of the heavy isotopes, C¹³, O¹⁸, S³⁴ suggest that these elements may be lost from the lunar surface by hydrogen stripping (from solar wind protons) as volatile gases. The general lack of water, suggests that organic synthesis could not easily be accomplished in lunar rocks. High energy irradiation of the lunar surface may result in rapid destruction of organic matter not protected by a silicate matrix. It is apparent from present data available, that the ambient lunar surface could not support metabolism of known microorganisms.Publication No. 997 Institute of Geophysics and Planetary Physics, University of California at Los Angeles, Los Angeles, California 90024.     

Quantitative and Qualitative Microbiological Profiles of the Apollo 10 and 11 Spacecraft

Microbiological profiles were determined for surfaces of the command module, lunar module (ascent and descent stages), instrument unit, Saturn S-4B stage, and the spacecraft lunar module adapter of the Apollo 10 and 11 spacecraft. Average levels of contamination of the command module were 2.1 x 10(4) and 2.7 x 10(4) microorganisms per ft(2) for Apollo 10 and 11, respectively. With the exception of the exterior surfaces of the ascent stage of the lunar module and the interior surfaces of the command module, average levels of microbial contamination on all components of the Apollo 11 were found to be lower than those observed on Apollo 10. For each Apollo mission, approximately 2,000 colonies were picked from a variety of media and identified. The results showed that approximately 95% of all isolates were those considered indigenous to humans; the remaining were associated with soil and dust in the environment. However, the ratio of these two general groups varied depending on the degrees of personnel density and environmental control associated with each module.     

睡莲科(Nymphaeaceae)管状分子的研究进展

睡莲科在被子植物中地位比较特殊,形态上复杂、多样,是系统研究的重要材料之一。一直以来,该科的解剖学上无导管的特征倍受关注。基于APG分类系统,对睡莲科的6个属的管状分子研究的现状做介绍和比较,并就其中存在的问题做了分析,指出过渡态导管需要统一的判断标准;而睡莲科的管状分子有必要做进一步的研究。     

Polypyrazolates of the heavier group 13 and 14 elements: A review

Heavy group 13 and 14 analogs of the poly(pyrazolyl)borates are the subject of this review. Within these, the most extensive research has been performed on the study of polypyrazolylgallates Me₂Ga(R₂pz)₂]⁻ (R = H or Me) and [MeGa(pz)₃]⁻, and their complexes with transition metals. In this review, the common features shared with the boron analogs are presented and contrasted. Other recently reported series of group 13 analogs are the alkali polypyrazolylaluminates Na[(R₂pz)₃] with R = Me, ^tBu; R′ = M. The complexes with one or two pyrazolyl ligands on aluminum display anagostic Al-CH₃?Na interactions, these interactions are persistent even if complexes were obtained from solutions with THF that normally coordinate alkali ions. The polypyrazolylsilane ligands Me₂Si(R₂pz)₂ and MeSi(R₂pz)₃ with R = H, Me are remarkably easy to obtain and isolate, in contrast is the fact that the carbon analogs are much harder to obtain and isolate in reasonable yields. Therefore it is surprising that the chemistry of the former ligands is not as developed as could be anticipated. Nevertheless there are examples of the use of these silanes as ligands with the following transition metals: Cr, Mn, Cu, Zn, Sc and Zr. The heavier group 14 analogs with Ge and Sn display coordination patterns with alkali and alkaline ions that resemble those observed with the borates and aluminates. The formation of cationic bimetallic cages of the type [E₂(R₂pz)₃]⁺ and neutral complexes [E₂(R₂pz)₄] has also been observed that can be consider formal isomers of the alkenes. The use of these compounds as ligands has been recently reported.     

IS231 and otherBacillus thuringiensis transposable elements: A review

Bacillus thuringiensis is an entomopathogenic bacterium whose toxicity is due to the presence in the sporangia of -endotoxin crystals active against agricultural pests and vectors of human and animal diseases. Most of the genes coding for these toxin proteins are plasmid-borne and are generally structurally associated with insertion sequences (IS231, IS232, IS240, ISBT1 and ISBT2) and transposons (Tn4430 and Tn5401). Several of these mobile elements have been shown to be active and are believed to participate in the crystal gene mobility, thereby contributing to the variation of bacterial toxicity. Structural analysis of the iso-IS231 elements indicates that they are related to IS1151 fromClostridium perfringens and distantly related to IS4 and IS186 fromEscherichia coli. Like the other IS4 family members, they contain a conserved transposase-integrase motif found in other IS families and retroviruses. Moreover, functional data gathered from IS231 A inEscherichia coli indicate a non-replicative mode of transposition, with a marked preference for specific targets. Similar results were also obtained inBacillus subtilis andB. thuringiensis, and a working model for DNA-protein interactions at the target site is proposed.     

Compounds produced from potential tunicate-blue-green algal symbiosis: A review

Tunicates of the family Didemnidae can be host to two genera of blue-green algae:Synechocystis andProchloron. The presence of symbiotic algae raises questions as to the exact origin of the biologically important metabolites which have been isolated from tunicates in recent years. Is the compound produced by the tunicate, the alga, or through a combined effort of both organisms? Although this question cannot be fully addressed at the present time, there is evidence which supports the argument that the metabolic origin of certain ascidian metabolites resides in the alga, or is due to a collaborative effort of both organisms. The purpose of this review is to present compounds isolated from tunicates that possess a likely symbiotic relationship with eitherSynechocystis orProchloron. Attention will also be given to the ecology of the organisms and the biological activities of metabolites isolated.     

环境中人为来源的铂族元素及其迁移转化研究进展

铂族元素(PGEs)在汽车尾气催化转换器(VECs)、工业催化剂和制药学领域的广泛应用,致使PGEs尤其是铂(Pt)、钯(Pd)和铑(Rh)在某些区域已经成为新型环境污染物.由于环境样品中Pt/Pd、Pt/Rh与VECs中活性成分比例有较好的相关性,因此PGEs污染主要来源于应用了铂族金属的VECs.研究显示,过去的30年里,气溶胶、永生态系统(河水、雨水、地下水、海水、沉积物)、土壤、路尘和生物有机体等不同环境介质中PGEs浓度均显著增加.人们普遍认为铂族元素是惰性的,暴露于环境中的PGEs的健康风险很小,但PGEs毒性和生物可利用性的研究表明,在多种生物地球化学过程作用下,人为排放的PGEs易发生迁移,转化为毒性更大的形态,增加生物可利用性,通过食物链传递对人类产生潜在的健康风险.本文对不同环境介质中PGEs来源、分布及生物地球化学行为的最新成果进行了总结,认为PGEs人体健康风险标准制定、PGEs标准物质的研制、近海沉积物中PGEs的研究、PGEs对滩涂贝类的毒性、食物中PGEs的污染现状及人体健康风险评估等是今后PGEs研究的重要领域.     

Determination of trace elements in human lung samples

Biological Trace Element Research - Lung samples from smokers, nonsmokers, and one stillborn were analyzed by an instrumental neutron activation analysis (INAA) method. Pulmonary tissue and hilum...     

Rare earth elements in soil and plant systems - A review

The rare earth elements (REEs) form a chemically uniform group and include yttrium (Y), lanthanum (La) and the lanthanides cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Their average abundance in the Earth’s crust range from 66μg g⁻¹ in Ce to 0.5μg g⁻¹ in Tm and ?0.1μg g⁻¹ in Pm. Recent great improvements in more routine analytical technique, the use of REEs as fertilisers, at least in East Asian agriculture, and the importance of these elements as indicators in both pedological and physiological processes and reactions have contributed to an increased interest in these previously less considered elements in environmental sciences. This review of recent and current literature deals with REEs in primary and secondary soil minerals, concentrations in surface soils, factors influencing adsorption, solubility and transport in soils, including weathering and transformations of REE minerals, and vertical distribution in soil profiles. Reviewed and discussed are also concentrations, distribution and localisation of REEs in plants and plant organs, soil-plant relationships and interactions, effects on plant growth and crop production and their importance in plant physiology and biochemistry. The REEs are found, usually several elements together, as phosphates, carbonates and silicate minerals finely dispersed especially in magmatic and metamorphic rocks. REE concentrations in surface soils of humid climates, such as the A(E)-horizons of Podzols and Laterites, are usually lower than in the parent material, due to higher weathering and leaching rates than of the average soil constituents. Some fractionation may occur due to the formation of more element-specific secondary minerals. Transfer from soil to plant is usually low, but extreme accumulators are found, e.g., among several species of ferns. Roots have generally higher concentrations than shoots. Possible uptakemechanisms of REEs are discussed. Uptake is positively, though often weakly, correlated with soil acidity and easily soluble concentrations of the elements, but rarely well related to their total concentrations in the soil. Under certain conditions, low concentrations of at least some REEs seem to favour plant growth and productivity, but the physiological mechanisms are still not well understood. Some considerations concerning the boundary between essential and non-essential micro nutrients are discussed.     

Ring chromosome 11. A case report and review of the literature

A female infant with severe growth-weight retardation and with a ring chromosome 11, associated with trisomy X in 15% of metaphases, has been reported. A literature review of cases of r(11) shows that the clinical features of these patients, although showing different frequencies, are similar to those of the del(11q) syndrome. It has been suggested that the variability of the mental retardation in r(11) patients is attributable to the unstability of the ring and to the different break points in these two chromosomal rearrangements. The origin of the r(11) was also addressed by studying fragile sites of the parents at 11p15 and 11q25.     

Trace elements in prehispanic hair samples of Gran Canaria

In the present study we have analysed hair Zn, Cu, Fe, Mn, Sr, Pb and Ca contents of 8 prehispanic hair specimens from Gran Canaria, comparing them with 10 acutal samples, which serve as a «control» group. Prehispanic samples showed statistically significant less Zn (t=2.81, p<0.02) and Cu (t=5.07, p<0.001) than the controls. On the other hand, Sr was higher in the prehispanic samples (t=4.42, p<0.001), as Fe (t=3.92, p<0.005), Pb (t=3.14, p<0.01) and especially Mn did (p<0.0001). No differences were observed regarding hair calcium content. These data are in accordance with results obtained in bone samples of the prehispanic inhabitants of this island, supporting the point of view that they consumed a mainly vegetarian diet, a statement which is in accordance with other archaeological and etnohistorical data.     

Trace elements in buried human bones and their value. A review

Since more than a decade, the trace element content of archaeological human bones is analyzed by physical anthropologists. Some of these elements give clues to the diets of ancient populations, others serve in estimating weaning age and the length of the active reproductive time span in human females. Therefore, trace element analysis becomes very important for palaeodemography and palaeoecology. On the other hand, a lot of basic research still has to be carried out, especially concerning the alteration of trace element concentrations in ancient bones either by soil processes or by microorganisms. The lack of reference series is obvious. Recommendations for the techniques to be applied are given, the parameters which may bias the interpretation of the data are discussed and the diagnostic potential of trace element analysis is demonstrated.