Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Highly Efficient Zirconium-Catalyzed Batch Conversion of 1-Butene: A New Route to Jet Fuels

Quantitative conversion of 1-butene to a Schultz−Flory distribution of oligomers has been accomplished by use of Group 4 transition-metal catalysts in the presence of methylaluminoxane (MAO). The oligomerization reaction was carried out at ambient temperature in a sealed reaction vessel with complete conversion of 1-butene at catalyst turnover numbers of >17 000. The combination of high catalyst activity without concomitant production of high polymer led to a highly efficient production of new hydrocarbon jet fuel candidates. The reaction proceeds with high regioselectivity; however, because achiral catalysts were used, several diastereoisomeric structures were produced and observed in the gas chromatography−mass spectrometry (GC−MS) chromatograms. The single and specific dimer formed in the reaction, 2-ethyl-1-hexene, was easily removed by distillation and then dimerized using acid catalysis to afford a mixture of mono-unsaturated C₁₆ compounds. Changes in the oligomerization catalyst led to production of fuels with excellent cold-flow viscosity without the need for a high-temperature distillation. Thus, removal of the dimer followed by catalytic hydrogenation (PtO₂) led to a 100% saturated hydrocarbon fuel with a density of 0.78 g/mL, a viscosity of 12.5 cSt at −20 °C (ASTM 445), and a calculated heat of combustion of 44+ MJ/kg. By back-addition of hydrogenated dimer in varying amounts (6.6, 11.5, and 17 wt %), it was possible to tailor the viscosity of the fuel (8.5, 7, and 6.5 cSt, respectively)

High-Density Renewable Fuels Based on the Selective Dimerization of Pinenes

High-density fuel candidates have been synthesized in up to 90% yield from β-pinene, a renewable strained bicyclic compound derived from wood and plant sources. The process is based on the heterogeneous acidic catalysts Montmorillonite-K10 and Nafion, which promote selective isomerization and dimerization of pinenes under moderate conditions (100 °C and atmospheric pressure). Montmorillonite-K10 was shown to be a highly active catalyst for dimerization but was also active in the ring opening of β-pinene followed by dehydrogenation to produce <i>p</i>-cymene, which limited the yield of the dimer to ca. 75%. Nafion was capable of producing dimers in up to 90% yield primarily through isomerization followed by dimerization. Amberlyst-15, a common industrial catalyst had very poor activity and conversion even at 150 °C. The dimer mixtures were upgraded through hydrogenation over PtO₂ and fractional distillation. The synthesized fuels have a density of 0.94 g/cm³ and a net volumetric heating value of 39.5 MJ/L (141 745 BTU/gallon). These values are nearly identical to those for the widely used tactical fuel JP-10 (primarily composed of exotetrahydrodicyclopentadiene), suggesting that these renewable fuels may have applications for rocket propulsion

The Pathogenomic Sequence Analysis of B. cereus and B. thuringiensis Isolates Closely Related to Bacillus anthracis

The sequencing and analysis of two close relatives of Bacillus anthracis are reported. AFLP analysis of over 300 isolates of B. cereus, B. thuringiensis and B. anthracis identified two isolates as being very closely related to B. anthracis. One, a B. cereus, BcE33L, was isolated from a zebra carcass in Nambia; the second, a B. thuringiensis, 97-27, was isolated from a necrotic human wound. The B. cereus appears to be the closest anthracis relative sequenced to date. A core genome of over 3,900 genes was compiled for the Bacillus cereus group, including B anthracis. Comparative analysis of these two genomes with other members of the B. cereus group provides insight into the evolutionary relationships among these organisms. Evidence is presented that differential regulation modulates virulence, rather than simple acquisition of virulence factors. These genome sequences provide insight into the molecular mechanisms contributing to the host range and virulence of this group of organisms

Pathogenomic Sequence Analysis of Bacillus cereus and Bacillus thuringiensis Isolates Closely Related to Bacillus anthracis

Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspicuous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound, and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia. These two strains, when analyzed by amplified fragment length polymorphism within a collection of over 300 of B. cereus, B. thuringiensis, and B. anthracis isolates, appear closely related to B. anthracis. The B. cereus E33L isolate appears to be the nearest relative to B. anthracis identified thus far. Whole-genome sequencing of B. thuringiensis 97-27and B. cereus E33L was undertaken to identify shared and unique genes among these isolates in comparison to the genomes of pathogenic strains B. anthracis Ames and B. cereus G9241 and nonpathogenic strains B. cereus ATCC 10987 and B. cereus ATCC 14579. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms

The Complete Genome Sequence of Bacillus thuringiensis Al Hakam

Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (3). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (2)

The Complete Genome Sequence of Bacillus thuringiensis Al Hakam

Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (3). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (2)