CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

Reaction centers from Rhodobacter sphaeroides have been modified by treatment with sodium borohydride similar to the original procedure [Ditson et al., Biochim. Biophys. Acta 766, 623 (1984)], and investigated spectroscopically and by gel electrophoresis. (1) Low temperature (1.2 K) absorption, fluorescence, absorption- and fluorescence-detected ODMR, and microwave-induced singlet-triplet absorption difference spectra (MIA) suggest that the treatment produces a spectroscopically homogeneous preparation with one of the ‘additional’ bacteriochlorophylls being removed. The modification does not alter the zero field splitting parameters of the primary donor triplet (TP870). (2) From the circular dichroism and Raman resonance spectra in the1500–1800 cm-1 region, the removed pigment is assigned to BchlM, e.g. the "extra" Bchl on the "inactive" M-branch. (3) A strong coupling among all pigment molecules is deduced from the circular dichroism spectra, because pronounced band-shifts and/or intensity changes occur in the spectral components assigned to all pigments. This is supported by distinct differences among the MIA spectra of untreated and modified reaction centers, as well as by Raman resonance. (4) The modification is accompanied by partial proteolytic cleavage of the M-subunit. The preparation is thus spectroscopically homogeneous, but biochemically heterogenous

In Vitro Synthesis of Chlorophyll A in the Dark Triggers Accumulation of Chlorophyll A Apoproteins in Barley Etioplasts”

An in vitro translation system using lysed etioplasts was developed to test if the accumulation of plastid-encoded chlorophyll a apoproteins is dependent on the de novo synthesis of chlorophyll a. The P700 apoproteins, CP47 and CP43, were not radiolabeled in pulsechase translation assays employing lysed etioplasts in the absence of added chlorophyll precursors. When chlorophyllide a plus phytylpyrophosphate were added to lysed etioplast translation assays in the dark, chlorophyll a was synthesized and radiolabeled P700 apoproteins, CP47 and CP43, and a protein which comigrates with D1 accumulated. Chlorophyllide a or phytylpyrophosphate added separately to the translation assay in darkness did not induce chlorophyll a formation or chlorophyll a apoprotein accumulation. Chlorophyll a formation and chlorophyll a apoprotein accumulation were also induced in the lysed etioplast translation system by the photoreduction of protochlorophyllide to chlorophyllide a in the presence of exogenous phytylpyrophosphate. Accumulation of radiolabeled CP47 was detectable when very low levels of chlorophyll a were synthesized de novo (less than 0.01 nmol/10(7) plastids), and radiolabel increased linearly with increasing de novo chlorophyll a formation. Higher levels of de novo synthesized chlorophyll a were required prior to detection of radiolabel incorporation into the P700 apoproteins and CP43 (greater than 0.01 nmol/10(7) plastids). Radiolabel incorporation into the P700 apoproteins, CP47 and CP43, saturated at a chlorophyll a concentration which corresponds to 50% of the etioplast protochlorophyllide content (0.06 nmol of chlorophyll a/10(7) plastids)

Time-Domain Separation of Optical Properties From Structural Transitions in Resonantly Bonded Materials

The extreme electro-optical contrast between crystalline and amorphous states in phase change materials is routinely exploited in optical data storage and future applications include universal memories, flexible displays, reconfigurable optical circuits, and logic devices. Optical contrast is believed to arise due to a change in crystallinity. Here we show that the connection between optical properties and structure can be broken. Using a unique combination of single-shot femtosecond electron diffraction and optical spectroscopy, we simultaneously follow the lattice dynamics and dielectric function in the phase change material Ge2Sb2Te5 during an irreversible state transformation. The dielectric function changes by 30% within 100 femtoseconds due to a rapid depletion of electrons from resonantly-bonded states. This occurs without perturbing the crystallinity of the lattice, which heats with a 2 ps time constant. The optical changes are an order-of-magnitude larger than those achievable with silicon and present new routes to manipulate light on an ultrafast timescale without structural changes

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons

AbstractChloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period

An Integrated Approach to Studying Rare Neuromuscular Diseases Using Animal and Human Cell-Based Models.

As sequencing technology improves, the identification of new disease-associated genes and new alleles of known genes is rapidly increasing our understanding of the genetic underpinnings of rare diseases, including neuromuscular diseases. However, precisely because these disorders are rare and often heterogeneous, they are difficult to study in patient populations. In parallel, our ability to engineer the genomes of model organisms, such as mice or rats, has gotten increasingly efficient through techniques such as CRISPR/Cas9 genome editing, allowing the creation of precision human disease models. Suc

Growth and predation activity at deep-sea hydrothermal vents along the Galápagos Rift

Growth rates of unclassified mussels collected from hydrothermal vents on the Pacific Ocean (2500 m) are among the highest recorded for deep-sea species. Mature mussels have mean growth rates of about 1 cm yr-1 which are comparable to growth rates of shallow water mussels...

Transnational Legal Practice 2006-07

This article reviews developments in transnational legal practice during 2006 and 2007, including international developments, U.S. developments and regional developments in Australia and Europe. The primary focus of the international developments section is the WTO\u27s General Agreement on Trade in Services (GATS). This article discusses GATS Track 1 Activities related to legal services, including the Legal Services Collective Requests and issues related to GATS Track 2 and the potential development of GATS disciplines. This section also surveys GATS-related initiatives of the American Bar Association and the International Bar Association and U.S. implementation of foreign lawyer multi-jurisdictional practice rules. In other areas, the international developments section addresses the development of a code of conduct for defense counsel practicing before the International Criminal Court and developments in the Financial Action Task Force (FATF). With respect to U.S. transnational legal practice developments, the article reviews U.S. bilateral free trade initiatives, lawyer discipline cooperation initiatives and significant litigation. The regional developments section documents the emergence in Australia of the first publicly-traded law firm and Australia\u27s efforts to promote greater multijurisdictional practice for Australian lawyers in the U.S. This section also reviews various European developments, including European competition law initiatives, the Akzo Nobel case currently pending before the European Court of Justice, and developments related to the free movement of lawyers, codes of conduct, money laundering and lawyer education

Transnational Legal Practice 2006-07

This article reviews developments in transnational legal practice during 2006 and 2007, including international developments, U.S. developments and regional developments in Australia and Europe. The primary focus of the international developments section is the WTO\u27s General Agreement on Trade in Services (GATS). This article discusses GATS Track 1 Activities related to legal services, including the Legal Services Collective Requests and issues related to GATS Track 2 and the potential development of GATS disciplines. This section also surveys GATS-related initiatives of the American Bar Association and the International Bar Association and U.S. implementation of foreign lawyer multi-jurisdictional practice rules. In other areas, the international developments section addresses the development of a code of conduct for defense counsel practicing before the International Criminal Court and developments in the Financial Action Task Force (FATF). With respect to U.S. transnational legal practice developments, the article reviews U.S. bilateral free trade initiatives, lawyer discipline cooperation initiatives and significant litigation. The regional developments section documents the emergence in Australia of the first publicly-traded law firm and Australia\u27s efforts to promote greater multijurisdictional practice for Australian lawyers in the U.S. This section also reviews various European developments, including European competition law initiatives, the Akzo Nobel case currently pending before the European Court of Justice, and developments related to the free movement of lawyers, codes of conduct, money laundering and lawyer education

Transnational Legal Practice 2006-2007

Law practice continues to expand across borders, and lawyers and law firms from the United States and other countries are substantially invested in representations that take them outside of their home jurisdictions.[1] Unfortunately, reliable information relating to the extent of internationalization of the legal market is scarce. Neither the number of lawyers and law firms working in the international legal services market nor the receipts generated from internationally-related work are readily and reliably available. Nevertheless, statistics from both the United States and United Kingdom provide a sense of the numbers from the largest present sources of international legal practice. In the category of outbound services, for example, we can consider how U.S. lawyers and law firms serve foreign clients and U.S.-based clients in their offshore activities. One measure of these services could include the offshore activity of U.S. law firms. The American Lawyer Global 100 includes nine U.S.-based law firms with more than a quarter of their lawyers stationed outside of the United States, three of which support more than 50 percent of their lawyers working from overseas offices.[2] Another study of approximately sixty large U.S. law firms reported that those firms support approximately 375 offices overseas, where approximately 8,000 lawyers are working;[3] three-quarters of these lawyers are working in offices located in Europe. The U.S. Department of Commerce Bureau of Economic Analysis estimates that the export of legal services from the United States generated $4.3 billion in receipts in 2005, while imports of legal services were valued at$914 million, yielding a 4:1 surplus for balance-of-payment accounts.[4] According to the U.K. Department of Constitutional Affairs, British law firms generated £1.9 billion in exports in 2003, compared to £1.5 billion in imports.[5