Kinase-mediated trapping of bi-functional conjugates of paclitaxel or vinblastine with thymidine in cancer cells

In the present work, we explore the possibility of introducing selectivity to existing chemotherapeutics via the design of non-pro-drug, bi-functional molecules comprising a microtubule-binding agent and a substrate for a disease-associated kinase. The design, synthesis, and in vitro biological evaluation of paclitaxel-thymidine and vinblastine-thymidine bi-functional conjugates are reported here. This work provides the first account of 'kinase-mediated trapping' of cancer therapeutics.     

Cross-talk between hematopoiesis and angiogenesis signaling pathways

The relationship between hematopoietic cells and endothelial cells has been seen as an indication that a common progenitor, the hemangioblast, gives rise to both cell types in the yolk sac, the initial site of hematopoiesis and blood vessel formation during mammalian development. The existence of angioblast-like circulating endothelial precursor cells in adults humans has recently been suggested. In this review, we have summarized the principle mechanisms involved in the cross-talk signaling pathway between hematopoiesis and angiogenesis in order to further understand how the hematopoietic and vascular systems are established during the development.     

Detection of pathogenic Vibrio parahaemolyticus in oyster enrichments by real time PCR

A real time polymerase chain reaction (PCR) assay was developed and evaluated to detect the presence of the thermostable direct hemolysin gene (tdh), a current marker of pathogenicity in Vibrio parahaemolyticus. The real time PCR fluorogenic probe and primer set was tested against a panel of numerous strains from 13 different bacterial species. Only V. parahaemolyticus strains possessing the tdh gene generated a fluorescent signal, and no cross-reaction was observed with tdh negative Vibrio or non-Vibrio spp. The assay detected a single colony forming unit (CFU) per reaction of a pure culture template. This sensitivity was achieved when the same template amount per reaction was tested in the presence of 2.5 microl of a tdh negative oyster:APW enrichment (oyster homogenate enriched in alkaline peptone water overnight at 35 degrees C). This real time technique was used to test 131 oyster:APW enrichments from an environmental survey of Alabama oysters collected between March 1999 and September 2000. The results were compared to those previously obtained using a streak plate procedure for culture isolation from the oyster:APW enrichment combined with use of a non-radioactive DNA probe for detection of the tdh gene. Real time PCR detected tdh in 61 samples, whereas the streak plate/probe method detected tdh in 15 samples. Only 24 h was required for detection of pathogenic V. parahaemolyticus in oyster:APW enrichments by real time PCR, whereas the streak plate/probe method required 3 days and was more resource intensive. This study demonstrated that real time PCR is a rapid and reliable technique for detecting V. parahaemolyticus possessing the tdh gene in pure cultures and in oyster enrichments.     

A Major Gene for Resting Metabolic Rate Unassociated with Body Composition: Results from the Québec Family Study

A major gene hypothesis for resting metabolic rate (RMR) was investigated using segregation analysis (POINTER) of data on families participating in Phase 2 of the Québec Family Study. Complete analyses were conducted on RMR adjusted for age, and also on RMR adjusted for age and other covariates, primarily fat mass (FM) and fat-free mass (FFM). Prior to adjustment for covariates, support for a major gene hypothesis was equivocal — i.e., there was evidence for either a major gene or a multifactorial component (i.e., polygenic and/or familial environment). The multifactorial model was preferred over the major gene model, although the latter did segregate according to Mendelian expectations. However, after the effects of FM and FFM were accounted for, a major gene effect was unambiguous and compelling. The putative locus accounted for 57% of the variance, affected 7% of the sample, and led to high values of RMR. The lack of a significant multifactorial effect suggested that the familial etiology of RMR adjusted for FM and FFM was likely to be entirely a function of the major locus. Comparing the RMR results from pre- and post-adjustment for FM and FFM suggests a plausible hypothesis. We know from earlier studies in this sample that there is a putative major gene for FM and a major non-Mendelian effect for FFM. The current study leads us to speculate that: (1) the gene(s) affecting body size and body composition also may have an effect on RMR, and further (2) removal of the effect of the major gene(s) for body size and composition allowed for detection of an additional major gene affecting only the RMR. Thus, RMR appears to be an oligogenic trait.     

Lateralized female topminnows can forage and attend to a harassing male simultaneously

Animals engaged in a complex task are often unable to allocateenough attention to a second concurrent task. We tested thehypothesis that cerebral lateralization is advantageous becauseit enables separate and parallel information processing andallows for a more efficient performance of concurrent cognitivetasks. Lateralized and nonlateralized (NL) female Girardinusfalcatus, obtained through a selective breeding experiment,were compared in a situation requiring sharing attention betweentwo simultaneous tasks, retrieving food items scattered on thesurface, and avoiding unsolicited male mating attempts. In thepresence of a sexually harassing male, lateralized females weresignificantly more efficient than NL females in retrieving food,while no difference between these groups was found in controlexperiments in which the male was absent and subjects were notrequired to share attention between foraging and vigilance.Lateralized females showed a negligible decrease in foragingrate while attending the additional task, suggesting that theymay be able to partition the two processes in different partsof the brain.     

A high-throughput plant DNA extraction method for marker analysis

The use of molecular markers to improve crops depends on the availability of rapid and efficient DNA extraction methods. Here we describe a simple and inexpensive method to isolate plant DNA suitable for RFLP, AFLP, and simple sequence repeat (SSR) analysis. This procedure uses stainless steel ball bearings to grind 16 samples simultaneously using a high-speed flask shaker. The method used in routine laboratory exercises yields 120–144 DNA extractions in a day by a single person at a cost of $0.60 (AUD) per sample, doubling the throughput of conventional methods.     

The NHERF1 PDZ2 domain regulates PKA-RhoA-p38-mediated NHE1 activation and invasion in breast tumor cells

Understanding the signal transduction systems governing invasion is fundamental for the design of therapeutic strategies against metastasis. Na(+)/H(+) exchanger regulatory factor (NHERF1) is a postsynaptic density 95/disc-large/zona occludens (PDZ) domain-containing protein that recruits membrane receptors/transporters and cytoplasmic signaling proteins into functional complexes. NHERF1 expression is altered in breast cancer, but its effective role in mammary carcinogenesis remains undefined. We report here that NHERF1 overexpression in human breast tumor biopsies is associated with metastatic progression, poor prognosis, and hypoxia-inducible factor-1alpha expression. In cultured tumor cells, hypoxia and serum deprivation increase NHERF1 expression, promote the formation of leading-edge pseudopodia, and redistribute NHERF1 to these pseudopodia. This pseudopodial localization of NHERF1 was verified in breast biopsies and in three-dimensional Matrigel culture. Furthermore, serum deprivation and hypoxia stimulate the Na(+)/H(+) exchanger, invasion, and activate a protein kinase A (PKA)-gated RhoA/p38 invasion signal module. Significantly, NHERF1 overexpression was sufficient to induce these morphological and functional changes, and it potentiated their induction by serum deprivation. Functional experiments with truncated and binding groove-mutated PDZ domain constructs demonstrated that NHERF1 regulates these processes through its PDZ2 domain. We conclude that NHERF1 overexpression enhances the invasive phenotype in breast cancer cells, both alone and in synergy with exposure to the tumor microenvironment, via the coordination of PKA-gated RhoA/p38 signaling.     

Epsilon substituted lysinol derivatives as HIV-1 protease inhibitors

A series of HIV-1 protease inhibitors containing an epsilon substituted lysinol backbone was synthesized. Two novel synthetic routes using N-boc-l-glutamic acid alpha-benzyl ester and 2,6-diaminopimelic acid were developed. Incorporation of this epsilon substituent enabled access to the S2 pocket of the enzyme, affording high potency inhibitors. Modeling studies and synthetic efforts suggest the potency increase is due to both conformational bias and van der Waals interactions with the S2 pocket.     

6-Amino-4-oxo-1,3-diphenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonyl derivatives as a new class of potent inhibitors of Interleukin-8-induced neutrophil chemotaxis

A series of 6-amino-4-oxo-1,3-diphenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonyl derivatives was synthesized. The compounds demonstrated to be novel, potent and selective inhibitors of Interleukin-8-induced human neutrophil chemotaxis. A SAR study was performed by varying the carbonyl function at position 5 and the chain linked to the amino group at position 6 of the scaffold. All the compounds of the series displayed inhibitory activity at nano- or picomolar concentrations against Interleukin-8-driven migration and no activity against fMLP- and C5a-induced chemotaxis. The binding tests of selected compounds on CXCR1 and CXCR2 receptors were negative. The most potent derivative showed in vivo efficacy in a mouse model of Zymosan-induced peritonitis.     

Parasitism by the mite Acarophenax lacunatus on beetle pests of stored products

Recent reports of the biocontrolpotential of the mite species Acarophenaxlacunatus (Cross & Krantz) (Prostigmata:Acarophenacidae) and the lack of biologicalstudies on this regulatory agent led to thepresent study carried out under laboratoryconditions. The objective of the investigationwas to assess the host range of A. lacunatus,so far only reported as egg parasite ofRhyzopertha dominica (F.) (Coleoptera:Bostrichidae). Four Coleoptera species ofstored cereals were used: R. dominica,Tribolium castaneum (Herbst) (Tenebrionidae),Cryptolestes ferrugineus (Stephens)(Laemophloeidae) and Oryzaephilus surinamensis (L.) (Cucujidae). The highest rates of eggparasitism were observed on R. dominica and T.castaneum, leading to a significant decrease ofpopulations of both species and reduced wheatweight loss. A. lacunatus was also able toparasitize eggs of C. ferrugineus, but not ofO. surinamensis. These results indicate abroader host range of A. lacunatus thaninitially suspected and also strengthen itspossibility of use in integrated pestmanagement programs in storage environments.