Threonine

Ibrutinib, which irreversibly inhibits Bruton tyrosine kinase, was evaluated for antitumor activity in a panel of non-small cell lung cancer (NSCLC) cell lines and found to selectively inhibit growth of NSCLC cells carrying mutations in the epidermal growth factor receptor (EGFR) gene, including T790M mutant and erlotinib-resistant H1975 cells. Ibrutinib induced dose-dependent inhibition of phosphor-EGFR at both Y1068 and Y1173 sites, suggesting ibrutinib functions as an EGFR inhibitor. Survival was analyzed by Kaplan-Meier estimation and log-rank test. All statistical tests were two-sided. In vivo study showed that ibrutinib statistically significantly suppressed H1975 tumor growth and prolonged survival of the tumor bearing mice (n = 5 per group). The mean survival times for solvent- and erlotinib-treated mice were both 17.8 days (95% confidence interval [CI] = 14.3 to 21.3 days), while the mean survival time for ibrutinib-treated mice was 29.8 days (95% CI = 26.0 to 33.6 days, P ...

A progressive supranuclear palsy (PSP)-like syndrome due to vascular or anoxic brain insult is rare. We describe a 65-year-old man with a progressive PSP-like phenotype associated with hypoxic–ischemic bilateral striopallidal lesions, secondary to rupture of and subsequent surgery for a thoracic aortic aneurysm. After early extrapyramidal features, 10 months later he started to fall, and developed levator inhibition. A supranuclear gaze palsy for downgaze was documented 5.5 years after the insult. © 2005 Movement Disorder Society

Bacillus subtilis 168 trp- was found to be transformable with the tetracycline resistance plasmid pAB124 by electroporation of whole cells, inconsistently and at very low frequencies. Supplementation of the growth medium with glycine, or particularly DL-threonine, produced cells that could be electrotransformed much more efficiently at frequencies up to 2.5 x 10(3) transformants per microgram plasmid DNA. Transformation was optimal with cells grown in medium containing a racemic mixture of the D- and L-isomers of threonine, and no transformants were obtained when pure forms of the D- and L-threonine isomers were used. The cell walls of B. subtilis grown in the presence or absence of D-, L- and DL-threonine had a similar amino acid composition which did not include threonine. A more complex biochemical explanation of the enhancement of electroporation by growth in DL-threonine is likely, and this is discussed. Lysozyme treatments to weaken the cell wall and possibly mimic the effect ...

A defining feature of all transferrins is the absolute dependence of iron binding on the concomitant binding of a synergistic anion, normally but not necessarily carbonate. Acting as a bridging ligand between iron and protein, it completes the coordination requirements of iron to lock the essential metal in its binding site. To investigate the role of the synergistic anion in the iron-binding and iron-donating properties of human transferrin, a bilobal protein with an iron binding site in each lobe, we have selectively mutated the anion-binding threonine and arginine ligands that form an essential part of the electrostatic and hydrogen-bonding network holding the synergistic anion to the protein. Preservation of either ligand is sufficient to maintain anion binding, and therefore iron binding, in the mutated lobe. Arginine is a stronger ligand than threonine, and its loss weakens carbonate and therefore iron binding, but maintains the ability of nitrilotriacetate to serve as a carbonate surrogate. Replacement of both ligands abolishes anion binding and consequently iron binding in the affected lobe. Loss of anion binding in either lobe results in a monoferric protein binding iron in normal fashion only in the opposite lobe. Both monoferric proteins are capable of transferrin receptor-dependent binding and iron donation to K562 cells, but with diminished receptor occupancy by the protein bearing iron only in the N-lobe.

The mitotic checkpoint protein Bub1 is essential for embryogenesis and survival of proliferating cells, and bidirectional deviations from its normal level of expression cause chromosome missegregation, aneuploidy, and cancer predisposition in mice. To provide insight into the physiological significance of this critical mitotic regulator at a modular level, we generated Bub1 mutant mice that lack kinase activity using a knockin gene-targeting approach that preserves normal protein abundance. In this paper, we uncover that Bub1 kinase activity integrates attachment error correction and mitotic checkpoint signaling by controlling the localization and activity of Aurora B kinase through phosphorylation of histone H2A at threonine 121. Strikingly, despite substantial chromosome segregation errors and aneuploidization, mice deficient for Bub1 kinase activity do not exhibit increased susceptibility to spontaneous or carcinogen-induced tumorigenesis. These findings provide a unique example of a modular mitotic activity orchestrating two distinct networks that safeguard against whole chromosome instability and reveal the differential importance of distinct aneuploidy-causing Bub1 defects in tumor suppression.

Sarcoplasmic reticulum (SR) dysfunction is one of the multiple alterations that occurs in ischemia-reperfused hearts. Because SR function is regulated by phosphorylation of phospholamban (PLB), a SR protein phosphorylated by cAMP-dependent protein kinase (PKA) at Ser16and Ca2+-calmodulin-dependent protein kinase (CaMKII) at Thr17, the phosphorylation of these residues during ischemia and reperfusion was examined in Langendorff-perfused rat hearts. Ser16phosphorylation increased significantly after 20 min of ischemia from 2.5±0.6% to 99.8±25.5% of maximal isoproterenol-induced site-specific phosphorylation and decreased to control values immediately after reperfusion. Thr17phosphorylation transiently increased at 2–5 min of ischemia and at 1 min of reperfusion (R1, 166.2±28.2%). The ischemia-induced increase in Ser16phosphorylation was significantly diminished in hearts from catecholamine-depleted animals and/or after β -blockade and abolished in the presence of the PKA-inhibitor, H-89. Thr17phosphorylation at the beginning of ischemia was blunted by nifedipine, whereas at R1 it was significantly diminished by perfusion with 0 m Ca2+in the presence of EGTA and by the Na+/Ca2+exchanger inhibitor KB-R7943. KN-93, used to specifically inhibit CaMKII, decreased Thr17phosphorylation at R1 and significantly prolonged half relaxation time. The results demonstrated a dissociation between the phosphorylation of PLB sites, being phosphorylation of Ser16dependent on the β -adrenergic cascade during ischemia and phosphorylation of Thr17on Ca2+influx both, at the beginning of ischemia and reperfusion. Phosphorylation of Thr17at the onset of reflow may provide the cell a mechanism to cope with Ca2+overload, transiently favoring the recovery of relaxation during early reperfusion.

Net portal absorption of AA during the 6-h postprandial period was measured in eight gilts (48.5 ± 1.6 kg BW) in a crossover design. The pigs had chronic catheters placed in the portal vein, carotid ar- tery, and ileal vein, and were trained to consume 1.2 kg of a standard grower diet once daily. Blood samples were taken every 30 min for 4 h and then hourly until 6 h after feeding. The first set of blood samples was taken after pigs were fed a meal of the test 16% CP corn-soybean meal diet (16% CP) or the test 12% CP corn-soybean meal diet supplemented with crystalline lysine, threonine, and tryptophan (12% CP + AA) to equal the three AA levels in the 16% CP diet. Pigs were then fed the standard diet for 2 d. Following that, blood samples were again taken after the pigs were fed a meal of the test diet that was not given to them at the first sampling period. Net portal AA absorption was calculated by multiplying porto-arterial plasma AA con- centration difference by portal vein plas...

Sucrose is one of the most promising carbon sources for industrial fermentation. To achieve sucrose catabolism, the sucrose utilization operons have been introduced into microorganisms that are not able to utilize sucrose. However, the rates of growth and sucrose uptake of these engineered strains were relatively low to be successfully employed for industrial applications. Here, we report a practical example of developing sucrose-utilizing microorganisms using Escherichia coli K-12 as a model system. The sucrose utilizing ability was acquired by introducing only β-fructofuranosidase from three different sucrose-utilizing organisms (Mannheimia succiniciproducens, E. coli W, and Bacillus subtilis). Among them, the M. succiniciproducens β-fructofuranosidase was found to be the most effective for sucrose utilization. Analyses of the underlying mechanism revealed that sucrose was hydrolyzed into glucose and fructose in the extracellular space and both liberated hexoses could be transported by their respective uptake systems in E. coli K-12. To prove that this system can also be applied for the production of useful metabolites, the M. succiniciproducens β-fructofuranosidase was introduced into the engineered l-threonine production strain of E. coli K-12. This recombinant strain was able to produce 51.1 g/L l-threonine by fed-batch culture, resulting in an overall yield of 0.284 g l-threonine per g sucrose. This simple approach to make E. coli K-12 to acquire sucrose-utilizing ability and its successful biotechnological application can be employed to develop sustainable bioprocesses using renewable biomass.

Mefloquine, a drug used for treatment and prophylaxis of malaria, is known for its neuropsychiatric adverse effects. We hypothesized that neuropsychiatric adverse effects of mefloquine are associated with polymorphisms in the MDR1/ABCB1 gene that encodes for the efflux pump P-glycoprotein. The association between MDR1 C1236T, G2677T, and C3435T single-nucleotide polymorphisms and the occurrence of neuropsychiatric adverse effects was examined in a prospective cohort study of 89 healthy white travelers taking mefloquine. Of the subjects, 27 (28%) reported neuropsychiatric adverse effects, women significantly more frequently than men. Allele frequencies of the C1236T, G2677T, and C3435T polymorphisms were similar to those found in other white populations, and there was no significant association between any of the individual polymorphisms and neuropsychiatric adverse effects. However, women with the 1236TT, 2677TT, and 3435TT genotypes had a higher risk of neuropsychiatric adverse eff...