Searching for Evidence of Life in Deep Time and Space

Cyanobacterial mats provide insights into ancient benthic microbial communities and their biosignatures. Thick mats occupy hypersaline saltern ponds at Guerrero Negro, Baja California, Mexico. Mat biota maintains rapid rates of biogeochemical processes under steep and rapidly changing environmental gradients. Cycling of C, O, and S all increased identically with temperature, indicating the tight coupling of these cycles. An enormous microbial diversity exhibits a highly structured spatial distribution of populations. Combined universal clone libraries from all mat layers indicated Bacteria/Archaea/Eukarya ratios of 57:7:1. More than 10,000 unique bacterial sequences were present. The relative abundance of Archaea increased with depth - below 10 cm, solvent-extractable archaeal lipids were twice as abundant as bacterial lipids. Only 15 species of Eukarya were found among 890 clones analyzed. Degradation of the mats insoluble macromolecular organic fraction (IMOM) by hydropyrolysis released a complex variety of linear, branched and polycyclic alkane structures, e.g., hopanes, methylhopanes and steranes. Covalent binding of these biosignatures into IMOM aids their long-term geological preservation. Mars rover missions revealed evidence of long-lived fluvial lacustrine systems and organics in associated mudstones. NASAs Mars 2020 rover mission will examine sediments in Jezero crater, including a delta and shoreline carbonate deposits, environments that on Earth have sustained microbial mats

Plagiarism in e-learning systems: Identifying and solving the problem for practical assignments

A big part of life long learning is the move from residential lectures to distance education. Distance education falls under the multi-modal policy of the teaching institution and thereby a change in student contact. The lecturer facilitating the distance education course is also faced with a problem where the quality and originality of submitted assignments need to be checked. This has always been a difficult task, as going through practical assignments and looking for similarities is a tedious job. Software checkers are available, but as yet, have not been integrated into popular online e-learning systems. If closer contact and warning to students are given at an early stage the problem is minimized as they know they are being closely monitored. As will be shown in this article, plagiarism is a current problem with online practical submissions. We will also show how this problem can be minimized through the integration of plagiarism checking tools and other checking methods into e-learning systems

Dyslipidaemia

Modern clinical practice commonly deals with the complications of atherosclerosis both in acute and potentially life-threatening and severely debilitating manifestations, and in chronic manifestations that may result in marked impairment of exercise and working capacity. Epidemiological information and intervention with drugs clearly indicate that atherosclerosis can be limited. Plasma lipids have been implicated in the pathogenesis of atherosclerosis, with variable strength of association: severe metabolic errors increasing risk profoundly while ‘moderate’ hypercholesterolaemia and low concentrations of high-density lipoprotein in concert with other risk factors can also signify a high risk. Other clinical problems linked with errors in lipid and lipoprotein metabolism include pancreatitis, malabsorption and many other rarer syndromes

MORTGAGE FORECLOSURES AND THE NATIONAL CREDIT ACT: BALANCING THE RIGHTS OF THE CREDITOR AND THE RIGHTS OF THE DEBTOR IN LIGHT OF JAFTHA V SCHOEMAN

The right of a creditor to foreclose a mortgage agreement, usually against the default of the debtor, and the subsequent sale in execution of the hypothecated immovable property is an important part of any modern credit-driven economy. A creditor, as mortgagee, may rely on the common law right to foreclose a mortgage agreement as a legally sanctioned means to ensure the enforcement of the mortgage debt. However, the foreclosure of a mortgage agreement will invariably implicate a number of constitutional rights and principles that are protected by the Constitution of the Republic of South Africa, 1996 (the “Constitution”)

Lipoprotein metabolism and its derangements

The purpose of this article is to provide the medical practitioner with an understanding of lipids, lipoproteins and their metabolism and disorders. Such an understanding would enhance the assimilation of the sections on clinical assessment and treatment of dyslipoproteinaemia. Lipids may be defined as organic chemicals that are insoluble in water. In the biological context lipids are either carboxylic acids (fatty acids) or sterols, and their derivatives. Lipids are less dense than water and will float spontaneously or under centrifugal force. Cholesterol is the principal sterol in the animal kingdom and promotes the impenetrability of the phospholipid bilayer that constitutes the cell membrane. Additionally cholesterol is found in lipoproteins and in bile and is used to synthesise hormones and bile acids

Dietary lipid modification for mild and severe dyslipidaemias

The aim of this review is to place a historical perspective on linking dyslipidaemia with atherosclerosis and emphasises previous knowledge about the impact on the lipoprotein profile and health in persons with mild dyslipidaemia and in those with defined genetic disorders. CVD is becoming the leading cause of death and disability in developed and developing countries and is strongly related to lifestyle factors that influence plasma lipoprotein concentrations. It is established that risk of complications from atherosclerosis increases with increasing LDL and decreasing HDL and that there is potentiation of risk when these and other risk factors co-exist. High-fat diets used for losing body mass may increase risk through dyslipidaemia. Pharmaceutical modulation of the lipoproteins has lowered risk powerfully but residual risk persists, possibly relating to existing disease as well as progression relating in many instances to dietary lipids. The impact of various dietary lipids is reviewed as they relate to the conventional lipoprotein profile in persons who do not have significant metabolic defects, as well as the impact on inherited metabolic disease such as familial hypercholesterolaemia, hypertriglyceridaemia and phytosterolaemia. For most persons with dyslipidaemias a significant benefit will be seen on the lipid profile by adopting a low saturated fat diet with less cholesterol intake

Marine Microbial Mats and the Search for Evidence of Life in Deep Time and Space

Cyanobacterial mats in extensive seawater evaporation ponds at Guerrero Negro, Baja California, Mexico, have been excellent subjects for microbial ecology research. The studies reviewed here have documented the steep and rapidly changing environmental gradients experienced by mat microorganisms and the very high rates of biogeochemical processes that they maintained. Recent genetic studies have revealed an enormous diversity of bacteria as well as the spatial distribution of Bacteria, Archaea and Eukarya. These findings, together with emerging insights into the intimate interactions between these diverse populations, have contributed substantially to our understanding of the origins, environmental impacts, and biosignatures of photosynthetic microbial mats. The biosignatures (preservable cells, sedimentary fabrics, organic compounds, minerals, stable isotope patterns, etc.) potentially can serve as indicators of past life on early Earth. They also can inform our search for evidence of any life on Mars. Mars exploration has revealed evidence of evaporite deposits and thermal spring deposits; similar deposits on Earth once hosted ancient microbial mat ecosystems

Astrobiology, Mars Exploration and Lassen Volcanic National Park

The search for evidence of life beyond Earth illustrates how the charters of NASA and the National Park Service share common ground. The mission of NPS is to preserve unimpaired the natural and cultural resources of the National Park System for the enjoyment, education and inspiration of this and future generations. NASA's Astrobiology program seeks to understand the origins, evolution and distribution of life in the universe, and it abides by the principles of planetary stewardship, public outreach, and education. We cannot subject planetary exploration destinations to Earthly biological contamination both for ethical reasons and to preserve their scientific value for astrobiology. We respond to the public's interest in the mysteries of life and the cosmos by honoring their desire to participate in the process of discovery. We involve youth in order to motivate career choices in science and technology and to perpetuate space exploration. The search for evidence of past life on Mars illustrates how the missions of NASA and NPS can become synergistic. Volcanic activity occurs on all rocky planets in our Solar System and beyond, and it frequently interacts with water to create hydrothermal systems. On Earth these systems are oases for microbial life. The Mars Exploration Rover Spirit has found evidence of extinct hydrothermal system in Gusev crater, Mars. Lassen Volcanic National Park provides a pristine laboratory for investigating how microorganisms can both thrive and leave evidence of their former presence in hydrothermal systems. NASA scientists, NPS interpretation personnel and teachers can collaborate on field-oriented programs that enhance Mars mission planning, engage students and the public in science and technology, and emphasize the ethics of responsible exploration

The Blue Dot Workshop: Spectroscopic Search for Life on Extrasolar Planets

This workshop explored the key questions and challenges associated with detecting life on an extrasolar planet. The final product will be a NASA Conference Publication which includes the abstracts from 21 talks, summaries of key findings, and recommendations for future research. The workshop included sessions on three related topics: the biogeochemistry of biogenic gases in the atmosphere, the chemistry and spectroscopy of planetary atmospheres, and the remote sensing of planetary atmospheres and surfaces. With the observation that planetary formation is probably a common phenomenon, together with the advent of the technical capability to locate and describe extrasolar planets, this research area indeed has an exciting future