403 research outputs found
Lachnospira pectinoschiza sp. nov., an Anaerobic Pectinophile from the Pig Intestine
Pectinophiles are bacteria that utilize pectin and only a few related compounds as substrates. Obligately anaerobic pectinophiles have been isolated from the intestinal tracts and gingivae of humans and from the rumina of cattle. We isolated three strains of pectinophilic bacteria from colonic contents of pigs but were unable to isolate pectinophiles from the rumen contents of four sheep, even when the animals were fed a high-pectin diet. The pectinophiles isolated from pigs were strictly anaerobic, motile, gram-positive rods (0.36 to 0.56 by 2.4 to 3.1 μm). Pectin, polygalacturonic acid, and gluconate were the only substrates that supported rapid growth. All three strains grew slowly on either lactose or cellobiose and fermented fructose after a lag of several days. Pectin was degraded by means of an extracellular pectin methylesterase and a Ca2+-dependent exopectate lyase. A comparison of the 16S rRNA sequences of these isolates with the 16S rRNA sequences of other gram-positive bacteria revealed a specific relationship with Lachnospira multipara (level of similarity, 94%). The Gram reaction, formation of spore-like structures, and the utilization of lactose and cellobiose differentiated the pig isolates from previously described pectinophiles. The pig isolates represent a previously undescribed species of the genus Lachnospira, for which we propose the name Lachnospira pectinoschiza
Program to Optimize Simulated Trajectories (POST). Volume 1: Formulation manual
A general purpose FORTRAN program for simulating and optimizing point mass trajectories (POST) of aerospace vehicles is described. The equations and the numerical techniques used in the program are documented. Topics discussed include: coordinate systems, planet model, trajectory simulation, auxiliary calculations, and targeting and optimization
In-situ measurements of the optical absorption of dioxythiophene-based conjugated polymers
Conjugated polymers can be reversibly doped by electrochemical means. This
doping introduces new sub-bandgap optical absorption bands in the polymer while
decreasing the bandgap absorption. To study this behavior, we have prepared an
electrochemical cell allowing measurements of the optical properties of the
polymer. The cell consists of a thin polymer film deposited on gold-coated
Mylar behind which is another polymer that serves as a counterelectrode. An
infrared transparent window protects the upper polymer from ambient air. By
adding a gel electrolyte and making electrical connections to the
polymer-on-gold films, one may study electrochromism in a wide spectral range.
As the cell voltage (the potential difference between the two electrodes)
changes, the doping level of the conjugated polymer films is changed
reversibly. Our experiments address electrochromism in
poly(3,4-ethylene-dioxy-thiophene) (PEDOT) and
poly(3,4-dimethyl-propylene-dioxy-thiophene) (PProDOT-Me). This closed
electrochemical cell allows the study of the doping induced sub-bandgap
features (polaronic and bipolaronic modes) in these easily oxidized and highly
redox switchable polymers. We also study the changes in cell spectra as a
function of polymer thickness and investigate strategies to obtain cleaner
spectra, minimizing the contributions of water and gel electrolyte features
Program to Optimize Simulated Trajectories (POST). Volume 3: Programmer's manual
Information pertinent to the programmer and relating to the program to optimize simulated trajectories (POST) is presented. Topics discussed include: program structure and logic, subroutine listings and flow charts, and internal FORTRAN symbols. The POST core requirements are summarized along with program macrologic
Long Polar Fimbriae Contribute to Colonization by \u3ci\u3eEscherichia coli\u3c/i\u3e O157:H7 In Vivo
The contribution of long polar fimbriae to intestinal colonization by Escherichia coli O157:H7 was evaluated in sheep, conventional pigs, and gnotobiotic piglets. E. coli O157:H7 strains with lpfA1 and lpfA2 mutated were recovered in significantly lower numbers and caused fewer attachment and effacement lesions than the parent strain
Genomic identification of a novel co-trimoxazole resistance genotype and its prevalence amongst Streptococcus pneumoniae in Malawi
Objectives
This study aimed to define the molecular basis of co-trimoxazole resistance in Malawian pneumococci under the dual selective pressure of widespread co-trimoxazole and sulfadoxine/pyrimethamine use.
Methods
We measured the trimethoprim and sulfamethoxazole MICs and analysed folA and folP nucleotide and translated amino acid sequences for 143 pneumococci isolated from carriage and invasive disease in Malawi (2002–08).
Results
Pneumococci were highly resistant to both trimethoprim and sulfamethoxazole (96%, 137/143). Sulfamethoxazole-resistant isolates showed a 3 or 6 bp insertion in the sulphonamide-binding site of folP. The trimethoprim-resistant isolates fell into three genotypic groups based on dihydrofolate reductase (encoded by folA) mutations: Ile-100-Leu (10%), the Ile-100-Leu substitution together with a residue 92 substitution (56%) and those with a novel uncharacterized resistance genotype (34%). The nucleotide sequence divergence and dN/dS of folA and folP remained stable from 2004 onwards.
Conclusions
S. pneumoniae exhibit almost universal co-trimoxazole resistance in vitro and in silico that we believe is driven by extensive co-trimoxazole and sulfadoxine/pyrimethamine use. More than one-third of pneumococci employ a novel mechanism of co-trimoxazole resistance. Resistance has now reached a point of stabilizing evolution. The use of co-trimoxazole to prevent pneumococcal infection in HIV/AIDS patients in sub-Saharan Africa should be re-evaluated
A streptococcus pneumoniae lineage usually associated with pneumococcal conjugate vaccine (PCV) serotypes is the most common cause of serotype 35B invasive disease in South Africa, following routine use of PCV
Pneumococcal serotype 35B is an important non-conjugate vaccine (non-PCV) serotype. Its continued emergence, post-PCV7 in the USA, was associated with expansion of a pre-existing 35B clone (clonal complex [CC] 558) along with post-PCV13 emergence of a non-35B clone previously associated with PCV serotypes (CC156). This study describes lineages circulating among 35B isolates in South Africa before and after PCV introduction. We also compared 35B isolates belonging to a predominant 35B lineage in South Africa (GPSC5), with isolates belonging to the same lineage in other parts of the world. Serotype 35B isolates that caused invasive pneumococcal disease in South Africa in 2005-2014 were characterized by whole-genome sequencing (WGS). Multi-locus sequence types and global pneumococcal sequence clusters (GPSCs) were derived from WGS data of 63 35B isolates obtained in 2005-2014. A total of 262 isolates that belong to GPSC5 (115 isolates from South Africa and 147 from other countries) that were sequenced as part of the global pneumococcal sequencing (GPS) project were included for comparison. Serotype 35B isolates from South Africa were differentiated into seven GPSCs and GPSC5 was most common (49 %, 31/63). While 35B was the most common serotype among GPSC5/CC172 isolates in South Africa during the PCV13 period (66 %, 29/44), 23F was the most common serotype during both the pre-PCV (80 %, 37/46) and PCV7 period (32 %, 8/25). Serotype 35B represented 15 % (40/262) of GPSC5 isolates within the global GPS database and 75 % (31/40) were from South Africa. The predominance of the GPSC5 lineage within non-vaccine serotype 35B, is possibly unique to South Africa and warrants further molecular surveillance of pneumococci
Scheduling language and algorithm development study. Volume 3: Detailed functional specifications for the language and module library
The detailed functional specifications presented are written as requirements for software implementation of the language and the program modules, and are aimed at a specific audience
Scheduling language and algorithm development study. Volume 2: Use of the basic language and module library
The capabilities of the specified scheduling language and the program module library are outlined. The summary is written with the potential user in mind and, therefore, provides maximum insight on how the capabilities will be helpful in writing scheduling programs. Simple examples and illustrations are provided to assist the potential user in applying the capabilities of his problem
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