Synthesis of pyrimidinopyridine-triazene conjugates targeted to abl tyrosine kinase

The synthesis and abl tyrosine kinase inhibitory activities of alkyltriazenes conjugated to phenylaminopyrimidines are described. Significant abl inhibitory activities were observed only when a benzamido spacer was inserted between the 1,2,3-triazene chain and the 2-phenyaminopyridopyrimidine moiety.     

Ultrastructural changes in the corpus allatum after azadirachtin and 20-hydroxyecdysone treatment in adult females of Labidura riparia (Dermaptera)

In previous reports, we have shown that the injection of azadirachtin (AZA) as well as 20-hydroxyecdysone (20E) into vitellogenic females of Labidura riparia induces inhibition of vitellogenin synthesis and ovarian development. Juvenile hormone (JH) treatment rescues vitellogenin synthesis and ovarian growth (Sayah et al., 1995, 1996). In this work, we have studied ultrastructural changes of corpus allatum (CA) after injection of 200, 400, and 600 ng of 20E or 1, 3, and 5 microg of AZA. CA cells exhibit signs of inactivity in both AZA and females treated with 20E at doses of 3 microg and 400 ng, respectively. Conspicuous cytological effects consisting of multivesicular bodies with dense contents, abnormally large intercellular spaces comprising myelinic structures, and rare smooth endoplasmic reticula occurred in cytoplasm of CA glandular cells in both experimental females. However, the CA ultrastructure of females injected with 20E differs from CA cells of females injected with AZA in having a cytoplasm containing numerous electron-lucent intracellular areas and marked glycogen zones. They also differ in having abundant microtubules and well-developed junctional membranes. At a dose of 600 ng of 20E or 5 microg of AZA, the intensity of the cytotoxic effects is more apparent. CA cells display pycnotic nuclei, spherical mitochondria, large multivesicular bodies, and vacuolization of the cytoplasm. These results are discussed and compared with observations made on other insect species.     

Cyclosporine attenuates the autonomic modulation of reflex chronotropic responses in conscious rats

Cyclosporine A (CyA), an immunosuppressant drug, has been shown to attenuate the baroreflex control of heart rate (HR). This study investigated whether or not the CyA-induced baroreflex dysfunction is due to alterations in the autonomic (sympathetic and parasympathetic) control of the heart. We evaluated the effect of muscarinic or beta-adrenergic blockade by atropine and propranolol, respectively, on reflex HR responses in conscious rats treated with CyA (20 mg x kg(-1) x day(-1) dissolved in sesame oil) for 11-13 days or the vehicle. Baroreflex curves relating changes in HR to increases or decreases in blood pressure (BP) evoked by phenylephrine (PE) and sodium nitroprusside (NP), respectively, were constructed and the slopes of the curves were taken as a measure of baroreflex sensitivity (BRS(PE) and BRS(NP)). Intravenous administration of PE and NP produced dose-related increases and decreases in BP, respectively, that were associated with reciprocal changes in HR. CyA caused significant (P < 0.05) reductions in reflex HR responses as indicated by the smaller BRS(PE) (-0.97 +/- 0.07 versus -1.47 +/- 0.10 beats x min(-1) x mmHg(-1) (1 mmHg = 133.322 Pa)) and BRS(NP) (-2.49 +/- 0.29 versus -5.23 +/- 0.42 beats x min(-1) x mmHg(-1)) in CyA-treated versus control rats. Vagal withdrawal evoked by muscarinic blockade elicited significantly lesser attenuation of BRS(PE) in CyA compared with control rats (40.2 +/- 8.0 versus 57.7 +/- 4.4%) and abolished the BRS(PE) difference between the two groups, suggesting that CyA reduces vagal activity. CyA also appears to impair cardiac sympathetic control because blockade of beta-adrenergic receptors by propranolol was less effective in reducing reflex tachycardic responses in CyA compared with control rats (41.6 +/- 4.2 versus 59.5 +/- 4.5%). These findings confirm earlier reports that CyA attenuates the baroreceptor control of HR. More importantly, the study provides the first pharmacological evidence that CyA attenuates reflex chronotropic responses via impairment of the autonomic modulation of the baroreceptor neural pathways.     

Multiplexed quantum dot labeling of activated c-Met signaling in castration-resistant human prostate cancer

The potential application of multiplexed quantum dot labeling (MQDL) for cancer detection and prognosis and monitoring therapeutic responses has attracted the interests of bioengineers, pathologists and cancer biologists. Many published studies claim that MQDL is effective for cancer biomarker detection and useful in cancer diagnosis and prognosis, these studies have not been standardized against quantitative biochemical and molecular determinations. In the present study, we used a molecularly characterized human prostate cancer cell model exhibiting activated c-Met signaling with epithelial to mesenchymal transition (EMT) and lethal metastatic progression to bone and soft tissues as the gold standard, and compared the c-Met cell signaling network in this model, in clinical human prostate cancer tissue specimens and in a castration-resistant human prostate cancer xenograft model. We observed c-Met signaling network activation, manifested by increased phosphorylated c-Met in all three. The downstream survival signaling network was mediated by NF-κB and Mcl-1 and EMT was driven by receptor activator of NF-κB ligand (RANKL), at the single cell level in clinical prostate cancer specimens and the xenograft model. Results were confirmed by real-time RT-PCR and western blots in a human prostate cancer cell model. MQDL is a powerful tool for assessing biomarker expression and it offers molecular insights into cancer progression at both the cell and tissue level with high degree of sensitivity.     

A sunflower BAC library suitable for PCR screening and physical mapping of targeted genomic regions

A sunflower BAC library consisting of 147,456 clones with an average size of 118 kb has been constructed and characterized. It represents approximately 5× sunflower haploid genome equivalents. The BAC library has been arranged in pools and superpools of DNA allowing screening with various PCR-based markers. Each of the 32 superpools contains 4,608 clones and corresponds to a 36 matrix pools. Thus, the screening of the entire library could be accomplished in less than 80 PCR reactions including positive and negative controls. As a demonstration of the feasibility of the concept, a set of 24 SSR markers covering about 36 cM in the sunflower SSR map (Tang et al. in Theor Appl Genet 105:1124–1136, 2002) have been used to screen the BAC library. About 125 BAC clones have been identified and then organized in 23 contigs by HindIII digestion. The contigs are anchored on the SSR map and thus constitutes a first-generation physical map of this region. The utility of this BAC library as a genomic resource for physical mapping and map-based cloning in sunflower is discussed.     

Association mapping in durum wheat grown across a broad range of water regimes

Association mapping was used to dissect the genetic basis of drought-adaptive traits and grain yield (GY) in a collection of 189 elite durum wheat accessions evaluated in 15 environments highly different for water availability during the crop cycle (from 146 to 711 mm) and GY (from 9.9 to 67.3 q ha(-1)). For highly heritable traits (e.g. heading date, kernel weight, etc.) several significant experiment-wise marker-trait associations were detected across five or more (up to 13 for kernel weight) environments, with R(2) values ranging from ca. 5 to 10%. As to GY, significant associations (R(2) from 2.5 to 4.2%) were mostly detected in one environment only (56 markers), while decreasing rapidly from two to five environments (from 20 to three markers, respectively) and with only one marker (Xbarc197 on chr. 5A) found significant in six environments (ranging from low- to high-yielding). These results are probably due to the complex genetic basis of GY and its interaction with environmental conditions. The number of markers significantly affecting GY decreased considerably under drought conditions, suggesting a limited effectiveness of association mapping to identify loci for GY under low-moisture conditions, most likely because different genotypes can attain similar phenotypes via different morpho-physiological traits and corresponding gene networks. Our study confirmed the role of major loci for phenology previously described in biparental mapping populations, highlighted a novel set of loci for drought-adaptive traits, and provided information on the agronomic value of the alleles at such loci across a broad range of soil moisture conditions.     

The effect of pH and anoxia on the performance of Phoslock, a phosphorus binding clay

This study examined the adsorption of phosphate by Phoslock, a lanthanum modified clay, by investigating the effect of solution pH and presence of algal mass on its kinetic behavior. In addition, the effect of anoxic conditions on its ability to retain the adsorbed phosphate was studied. It was found that Phoslok^® was most effective at pH values between 5 and 7, and the adsorption capacity decreased above pH 9. The adsorption capacity was lower in algae-containing lake water than in prepared reverse osmosis water solutions. The phosphorus was not released from the Phoslock^® under anoxic conditions.