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Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an effective strategy in the treatment of motorsymptoms in advanced Parkinson's disease. However, clinical studies have shown that DBS can affect verbal fluency. Seven Parkinson's disease patients with bilateral DBS of the STN were studied with positron emission tomography (PET) to investigate the effects of STN stimulation on regional cerebral blood flow during a verbal fluency task. Activation of the right orbitofrontal cortex and verbal fluency‐associated activation within a left‐sided frontotemporal network were decreased during STN stimulation compared with the OFF state. Our results offer an explanation for the commonest neuropsychological side effect of STN stimulation and show that STN stimulation affects a frontotemporal network during a fluency task. Ann Neurol 2003;54:000–000

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an effective strategy in the treatment of motor symptoms in advanced Parkinson's disease. However, clinical studies have shown that DBS can affect verbal fluency. Seven Parkinson's disease patients with bilateral DBS of the STN were studied with positron emission tomography (PET) to investigate the effects of STN stimulation on regional cerebral blood flow during a verbal fluency task. Activation of the right orbitofrontal cortex and verbal fluency-associated activation within a left-sided frontotemporal network were decreased during STN stimulation compared with the OFF state. Our results offer an explanation for the commonest neuropsychological side effect of STN stimulation and show that STN stimulation affects a frontotemporal network during a fluency task. Ann Neurol 2003;54:000–000

AbstractManagers of natural resources are faced with increasingly complex issues involving resource management concerns and the emerging importance of the socio-cultural context of resource use. The resource manager has been forced to respond and react to new social, cultural, ecological, and economic realities. Educational institutions have often been slow to respond to the changing work environment, even though a growing number of practitioners and educators believe that traditional approaches to training resource managers are inadequate and increasingly, ineffectual. This paper outlines the development of a new curriculum attempting to respond to the new challenges faced by contemporary resource managers. The concepts of interdisciplinary and cross-disciplinary study are described, and the need for a new educational approach is argued. Finally, one institution's response to the changing needs and skills of resource managers is reviewed.

Summary Sorption of cadmium by sediment bacteria and freshwater sediment was investigated using diffusion chambers to simulate the water-sediment interface. Diffusion chambers were constructed to provide two compartments separated by a dialysis membrane. Diffusion of cadmium across the membrane was monitored after pure cultures of sediment bacteria or lake sediments were added to the sediment side of a diffusion chamber. Cellular accumulation of cadmium by cadmium-sensitive and cadmium-resistant bacteria removed between 20% and 80% of the dissolved cadmium from the simulated water column and pore water. Cellular accumulation of cadmium was greatest for cadmium-sensitive isolates that were tested. Sediment with an intact microbial community sequestered 80% of the cadmium added to sediment, whereas autoclaved sediment retained 97% of the metal that was added. Addition of glucose to cadmium-amended sediment decreased retention of cadmium by untreated and autoclaved sediments, resulting in elevated concentrations of dissolved cadmium in the simulated water column.

Summary Zoogloea ramigera 115 was immobilized into beads of calcium-alginate and placed into batch air-bubbled column reactors. In the absence of any added nutrients the immobilized bacterium adsorbed Cd from solutions containing levels of 2 and 20 µg ml-1 per day, over a period of 21 and 20 days, respectively. Adsorption of Cd from solutions containing 20 µg ml-1 Cd was better than 90% for 16 days. Beads treated with Cd at 2 µg ml-1 never adsorbed less than 95% of the metal. Alginate adsorbed Cd as well, but inclusion of cells changed the effectiveness of adsorption. Of a 250 µg ml-1 Cd solution, alginate adsorbed 70.4% Cd in 60 min whereas alginate plus cells adsorbed 90.5% in the same time span. Temperature had no effect on adsorption by immobilized cells at levels of 2 and 10 µg ml-1 Cd. However at higher concentrations, binding was enhanced as temperature increased.Z. ramigera beads were stable during all treatments and for prolonged periods of time (21 days).

Cadmium-resistant bacterial populations were examined in sediments of the Ottawa River, near Lima, Ohio, at a site that had elevated levels of Cd, Cr, Cu, Ni, Zn, and Fe. The percentage of the bacterial population that was resistant to cadmium was higher at the metal-contaminated site than at a less contaminated site downstream.Bacillus was the most abundant genus of the total river sediment population recovered andPseudomonas was the most abundant Cd-resistant genus recovered. Types and distribution of bacterial populations in 40 liter laboratory model aquatic systems were examined over a ten-week period during the continuous addition of 10 mg Cd+2 per day. The Cd level in the water column rose rapidly through the first two weeks and reached a maximum of 3 µg Cd/ ml. Sediment Cd levels rose most rapidly after 5 weeks and reached a concentration of 270 µg Cd/g after 10 weeks. The bacteria in the water column responded to the Cd treatment with increased Cd resistance more quickly and to a greater degree than the bacteria in the sediment. The types of Cd-resistant bacteria isolated in the model systems were similar to Cd-resistant bacteria isolated from sediments of the Ottawa River.

High-efficiency disruption of bacteria can be accomplished in 2 or more min by the new procedure of liquid nitrogen cryo-impacting. Release of the dipicolinic acid-Ca2+chelate paralleled the breakage of Bacillus megateriumendospores. Lactate dehydrogenase activity was much better in supernates from liquid nitrogen cryo-impacting-broken Escherichia colicells than in those from sonically treated and broken E. colicells.

The effects of cadmium on the growth and respiration of two strains of Bacillus subtilis are compared to the accumulation of Cd by viable and cyanide-killed cells, protoplasts and cell fractions of the strains. Growth and respiration of strain 1A1 were significantly inhibited at 10µg Cd2+/ml while the growth and respiration of strain 1A1R, a selected mutant of 1A1, were only slightly affected. Similarly, 1A1R protoplasts were more resistant to Cd than were 1A1 protoplasts. The differential resistance of the strains correlates with the accumulation of Cd by the two strains, with 1A1 accumulating approximately 10 times the level of Cd after a 4 h exposure to 1 µg Cd2+/ml. The distributions of Cd throughout the cells, however, were similar between strains. Based on the accumulation of Cd by cyanide-killed protoplasts, uptake of Cd by 1A1 appears to be an active process, while for 1A1R, Cd accumulation is independent of protoplast viability.

Zoogloea ramigera 115 cells were immobilized into beads of calcium alginate and used in air-bubbled column reactors to remove cadmium (Cd), zinc (Zn), manganese (Mn), lead (Pb), copper (Cu) and strontium (Sr) from dilute and concentrated solutions. By placing three bubble columns in sequence it was possible to achieve Cd adsorption efficiencies of 99% or greater. During ten applications of approximately 100 µg·ml-1 Cd to three reactors in sequence, the immobilized Z. ramigera adsorbed 99.9% of the metal. The efficiency of the first column decreased from 92.2% on the first day to 53.8% on the tenth day, but the overall efficiency remained high because of the other two reactors. Exposure of bubble columns to mixed metal solutions yielded similar results. Cd, Zn, Mn, Cu, and Sr were adsorbed at 95.9% or better when concentrations in the mixtures ranged from 12 to 117 µg·ml-1 per metal. Pb was the least efficiently adsorbed metal with 81.3% and 74.7% removed from solutions containing 12 and 23 µg·ml-1, Pb respectively. Recovery and concentration of the metals was possible with nitrilotriacetic acid (NTA) treatment; which desorbed >77% of the accumulated Cd from the immobilized cells. Recovery of metals from beads which had been exposed to mixed metals depended on the metal; only 5.8% of the adsorbed Sr was recovered, but 98.3% of Zn was desorbed.

“Acid streamers” found in acid coal mine drainage consist of bacteria trapped within an extracellular fibrillar polymer network. Inorganic compounds also precipitate within the polymer network. Several bacteria which appear to be different and are presumed to be different species are associated in the slimy mass of the “acid streamers.” The “streamers” contain individual microcolonies or microcosms that can be recognized by a selective polysaccharide stain, which suggests that the slime streamer is a conglomeration of polymers produced by more than one species.

Five gram-negative bacteria, two gram-positive bacteria, and one yeast were isolated from “acid streamers” taken from acid mine water. One gram-positive rod which has been tentatively identified as a Bacillusspecies appeared to be the predominant organism in the streamers. This isolate produced copious amounts of extracellular polymer at 10 C in the laboratory and was considered to be the primary source of polymer in the “acid streamer” slime matrix. The organism grew slowly at pH 2.8 in mine water media, but the optimal pH was approximately 7.0.

The fingerlike projections, which have been considered to be characteristic of the genus Zoogloea, appear to consist of generally globular packets of cells, each surrounded by capsular matrix. The individual packets which surround Z. ramigera115 cells appear to adhere one to another by intermeshed fibrils that measure 2 to 5 nm in diameter. The fibril polymer appears to be polyglucose that is susceptible to cellulase. The polymer resembles cellulose in several respects, with the exception that it is soluble in 1 nNaOH. Although Z. ramigeraI-16-M does not possess an observable zoogloeal matrix when viewed under a light microscope, chemical data indicate that it does produce cellulase-susceptible polymer. Fibrils can be observed under the electron microscope, which are resistant to 1 nNaOH and may be cellulose. Less polymer fibrils are observed around isolate I-16-M cells than around isolate 115 cells; the inability to observe the I-16-M material as a zoogloeal matrix under light microscopy may be due to lack of sufficient amount of polymer.

Evidence is presented for the isolation and identification of bacteria able to synthesize an unusual antibiotic containing five bromine atoms per molecule. The identification and taxonomic position of these bacteria was made by use of a computer in conjunction with traditional methods. These microorganisms and closely related strains have been isolated on various occasions from tropical water in the vicinity of Puerto Rico. One bacterium, a pseudomonad, has been given the name Pseudomonas bromoutilisbecause of its distinctive capability. The antibiotic has been extracted, purified, and obtained in crystal form, and its structure has been determined. Although clinical tests of its properties were not encouraging, it may be of significant value and interest from an ecological standpoint.

Pfister, RobertM. (Lamont Geological Observatory, Palisades, N.Y.), and Paul R. Burkholder. Numerical taxonomy of some bacteria isolated from Antarctic and tropical seawaters. J. Bacteriol. 90:863–872. 1965.—Microorganisms from Antarctic seas and from tropical waters near Puerto Rico were examined with a series of morphological, physiological, and biochemical tests. The results of these analyses were coded on punch cards, and similarity matrices were computed with a program for an IBM 1620 computer. When the matrix was reordered by use of the single-linkage technique, and the results were plotted with four symbols for different per cent similarity ranges, nine groups of microorganisms were revealed. The data suggest that organisms occurring in different areas of the open ocean may be profitably studied with standardized computer techniques.

Several gram-negative, polarly flagellated rods were isolated on the basis of their flocculent growth habit. Some of the isolates possessed a capsular matrix which is composed of exocellular fibrils. Other isolates did not appear to have a capsular matrix when examined with a bright-field microscope with or without the aid of stains. However, these latter type isolates did possess exocellular material which can be demonstrated by adsorption of a fluorescent dye under an ultraviolet microscope. Electron microscopic examination demonstrated that the exocellular material around all isolates examined is fibrillar. The fibrils were susceptible to cellulase although all fibrils did not appear to be identical. It is postulated that the exocellular polymers were responsible for the flocculent growth habit of the bacteria, and that the process of bacterial flocculation produced by synthetic polyelectrolytes was essentially the same as that caused by naturally produced exopolymers.

The structure of the cell wall, the arrangement of the cyst exine, and the origin and distribution of intine vesicles in Azotobacter vinelandiiATCC 12837 were examined by freeze-etching and conventional electron microscopic techniques. In the vegetative organism the cell wall appears to have a woven texture which disappears during cyst formation. The exine is composed of two different types of material: the outer layer is a fibrous, amorphous layer, and the numerous inner layers form the basic hexagonal structures which unite to form the cyst coat. The presence of intine vesicles in the encysting organism was confirmed in frozen-etched cells. The appearance of frozen-etched cells and cysts and the distribution of capsular material indicate that extracellular polysaccharide is an important factor in cyst formation.

Bacillus subtilis, which accumulates cadnium via the manganese transport system, may acquire cadmium resistance by chromosomal mutations that reduce Cd2+ uptake without affecting Mn2+ transport. A cadmium resistance mutation,cdr-1, maps at about 40° on theB. subtilis chromosome. The deduced map order wasarol-narB-mtlB-cdr-dal-purB. Thecdr mutations in four other, independently isolated Cd2+-resistant mutants demonstrating reduced Cd2+ uptake also mapped betweenaroI anddal.

Floc-forming bacteria isolated from Lake Erie adsorb and concentrate aldrin from colloidal dispersion so that the settling of the bacterial flocs removes aldrin from the water phase. Contemporary sediments forming in Lake Erie contain aldrin and could adsorb more. The sediments consist of a conglomerate floc of bacteria, diatoms, and inorganic and detrital particles. Flocculent bacteria also adsorb microparticulates, and this adsorption capacity represents a mechanism for sediment formation and for the removal of suspended particles including aldrin from the water column.

Biological nitrogen fixation, as determined by acetylene reduction, occurs in Lake Erie. Fixation potential by blue-green algae in situ in water and by bacteria in collected sediments was demonstrated. Nitrogen-fixing activity occurred from June through November suggesting that it is significant over the extremes of seasonal variation in light, temperature, and nutrients.

Microparticulates suspended in lake water were collected by continuous centrifugation and either examined directly or placed on a linear sucrose gradient. Total residue as well as fractions of the centrifuged gradient were extracted with hexane and examined by gas chromatography for the presence of chlorinated hydrocarbon pesticides. Hexane extracts of total residues were also examined by thin-layer chromatography. Lindane and endrin were shown, by gas-liquid chromatography and thin-layer chromatography, to be associated with microparticles. These and other pesticides appeared to be selectively associated with microparticles of different densities, when gas-liquid chromatography was used, although concentrations were below the detection limits required for confirmation by thin-layer chromatography. Samples taken at different times from different locations in Lake Erie revealed different associations with hexane-soluble electron-capturing compounds.

The relationship between endogenous levels of cyclic adenosine 3′,5′-monophosphate (cAMP) and the formation of aerial mycelia was investigated in Streptomyces alboniger under conditions of aerial mycelium formation and repression. The relationship between cellular levels of DNA and RNA and aerial mycelium formation was also investigated. In contrast to cellular differentiation in other Streptomyces, neither variations in cAMP, DNA or RNA levels were found to be associated with the development of aerial mycelia in S. alboniger. The regulation of adenylate cyclase in S. alboniger, however, was found to differ from that of Escherichia coli and related organisms in that glucose raised, rather than lowered, endogenous cAMP levels.

This article features the video game, EverQuest. It notes that the game operates a lot like a medium-sized city. It has an infrastructure, a political system, an economic system; it has holidays, geography, and events. It has laws that are enforced, even its own type of health and safety system. And most important of all, it has a population. People live there, they elect representatives, they perform their jobs, they make new friends and stay in touch with old ones.