Antiestrogenic activity of flavonoid phytochemicals mediated via the c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha

Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling independent of direct receptor binding. Here we demonstrate both chalcone and flavone function as cell type-specific selective ER modulators. In MCF-7 breast carcinoma cells chalcone and flavone suppress ERα activity through stimulation of the stress-activated members of the mitogen-activated protein kinase (MAPK) family: c-Jun N-terminal kinase (JNK)1 and JNK2. The use of dominant-negative mutants of JNK1 or JNK2 in stable transfected cells established that the antiestrogenic effects of chalcone and flavone required intact JNK signaling. We further show that constitutive activation of the JNK pathway partially suppresses estrogen (E2)-mediated gene expression in breast, but not endometrial carcinoma cells. Our results demonstrate a role for stress-activated MAPKs in the cell type-specific regulation of ERα function.     

Hyperthermia increases interleukin-6 in mouse skeletal muscle

Skeletal muscles produce and contribute to circulating levels of IL-6 during exercise. However, when core temperature is reduced, the response is attenuated. Therefore, we hypothesized that hyperthermia may be an important and independent stimulus for muscle IL-6. In cultured C2C12 myotubes, hyperthermia (42°C) increased IL-6 gene expression 14-fold after 1 h and 35-fold after 5 h of 37°C recovery; whereas exposure to 41°C resulted in a 2.6-fold elevation at 1 h. IL-6 protein was secreted and significantly elevated in the cell supernatant. Similar but reduced responses to heat were seen in C2C12 myoblasts. Isolated soleus muscles from mice, exposed ex vivo to 41°C for 1 h, yielded similar IL-6 gene responses (>3-fold) but without a significant effect on protein release. When whole animals were exposed to passive hyperthermia, such that core temperature increased to 42.4°C, IL-6 mRNA in soleus increased 5.4-fold compared with time matched controls. Interestingly, TNF-α gene expression was routinely suppressed at all levels of hyperthermia (40.5-42°C) in the isolated models, but TNF-α was elevated (4.2-fold) in the soleus taken from intact mice exposed, in vivo, to hyperthermia. Muscle HSP72 mRNA increased as a function of the level of hyperthermia, and IL-6 mRNA responses increased proportionally with HSP72. In cultured C2C12 myotubes, when heat shock factor was pharmacologically blocked with KNK437, both HSP72 and IL-6 mRNA elevations, induced by heat, were suppressed. These findings implicate skeletal muscle as a "heat stress sensor" at physiologically relevant hyperthermia, responding with a programmed cytokine expression pattern characterized by elevated IL-6.     

On the synthesis of DNA error correcting codes

DNA error correcting codes over the edit metric consist of embeddable markers for sequencing projects that are tolerant of sequencing errors. When a genetic library has multiple sources for its sequences, use of embedded markers permit tracking of sequence origin. This study compares different methods for synthesizing DNA error correcting codes. A new code-finding technique called the salmon algorithm is introduced and used to improve the size of best known codes in five difficult cases of the problem, including the most studied case: length six, distance three codes. An updated table of the best known code sizes with 36 improved values, resulting from three different algorithms, is presented. Mathematical background results for the problem from multiple sources are summarized. A discussion of practical details that arise in application, including biological design and decoding, is also given in this study.     

Chloroplast genome sequence confirms distinctness of Australian and Asian wild rice

Cultivated rice (Oryza sativa) is an AA genome Oryza species that was most likely domesticated from wild populations of O. rufipogon in Asia. O. rufipogon and O. meridionalis are the only AA genome species found within Australia and occur as widespread populations across northern Australia. The chloroplast genome sequence of O. rufipogon from Asia and Australia and O. meridionalis and O. australiensis (an Australian member of the genus very distant from O. sativa) was obtained by massively parallel sequencing and compared with the chloroplast genome sequence of domesticated O. sativa. Oryza australiensis differed in more than 850 sites single nucleotide polymorphism or indel from each of the other samples. The other wild rice species had only around 100 differences relative to cultivated rice. The chloroplast genomes of Australian O. rufipogon and O. meridionalis were closely related with only 32 differences. The Asian O. rufipogon chloroplast genome (with only 68 differences) was closer to O. sativa than the Australian taxa (both with more than 100 differences). The chloroplast sequences emphasize the genetic distinctness of the Australian populations and their potential as a source of novel rice germplasm. The Australian O. rufipogon may be a perennial form of O. meridionalis.     

Temporal and spatial windows delimit activation of the outer ring of wingless in the Drosophila wing

Extracellular signalling molecules play many roles in the development of higher organisms. They are used reiteratively in different tissues and stages, but the response of the receiving cells is controlled in a context dependent manner. The pattern of expression of the signalling molecule Wingless/WNT in Drosophila is extraordinarily complex. We have studied the mechanism that controls its expression and function in the outer ring of the Drosophila wing hinge. Our findings indicate that wingless expression is controlled by a dual mechanism: its initial activation requires the product of zinc finger homeodomain 2 and is subsequently repressed by the product of the gene complex elbow/no ocelli. This tight regulation restricts the activation of wingless temporally and spatially. Later in development, wingless expression is maintained by an autoregulatory loop that involves the product of homothorax. We have analyzed the phenotype of a wingless allelic combination that specifically removes the outer ring, and our results show that Wingless is required to promote local proliferation of the wing base cells. Thus, cell proliferation in the proximal-distal axis is controlled by the sequential activation of wingless in the inner ring and the outer ring at different stages of development.     

Does juvenile competition explain displacement of a native crayfish by an introduced crayfish?

The coldwater crayfish Orconectes eupunctus is endemic to the Spring and Eleven Point Rivers of Arkansas and Missouri, and appears to have been displaced from a portion of its range by the recently introduced ringed crayfish Orconectes neglectus. We examined competition among juveniles as a potential mechanism for this crayfish species displacement through laboratory and field experiments. Orconectes eupunctus juveniles survived and grew in stream cages in their former range, implicating biotic interactions rather than habitat degradation in the displacement. Laboratory experiments revealed O. neglectus juveniles were dominant in the presence of limited food, whereas size rather than species determined occupancy of limited shelter. In a field competition experiment using stream cages, O. neglectus juveniles did not inhibit growth or reduce survival of O. eupunctus juveniles. Consequently, laboratory evidence of O. neglectus dominance did not correspond with competition under field conditions. Combined with previous studies examining the effects of O. neglectus on O. eupunctus, these results suggest that competition may not be a factor in this crayfish species displacement. Alternate mechanisms for the apparent displacement of O. eupunctus by O. neglectus, such as differential predation or reproductive interference, should be investigated.     

Identification of proteins interacting with Arabidopsis ACD11

The Arabidopsis ACD11 gene encodes a sphingosine transfer protein and was identified by the accelerated cell death phenotype of the loss of function acd11 mutant, which exhibits heightened expression of genes involved in the disease resistance hypersensitive response (HR). We used ACD11 as bait in a yeast two-hybrid screen of an Arabidopsis cDNA library to identify ACD11 interacting proteins. One interactor identified is a protein of unknown function with an RNA recognition motif (RRM) designated BPA1 (binding partner of ACD11). Co-immunoprecipitation experiments confirmed the ACD11-BPA1 interactions in vivo and in vitro. Two other ACD11 interactors (PRA7 and PRA8) are homologous to each other and to mammalian PRA1, and both were subsequently shown to interact with BPA1 in yeast. A fourth interactor (VAP27-1) is homologous to mammalian VAP-A, and was found to interact more strongly with a homolog of ACD11 than ACD11 itself. All interactors were shown to be associated with membrane fractions, suggesting that ACD11 function could be related to the regulation of membrane compartments.     

Methotrexate in rheumatoid arthritis is frequently effective, even if re-employed after a previous failure

Effectiveness of therapy with individual disease-modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis (RA) is limited, and the number of available DMARDs is finite. Therefore, at some stage during the lengthy course of RA, institution of traditional DMARDs that have previously been applied may have to be reconsidered. In the present study we investigated the effectiveness of re-employed methotrexate in patients with a history of previous methotrexate failure (original course). A total of 1,490 RA patients (80% female, 59% rheumatoid factor positive) were followed from their first presentation, yielding a total of 6,470 patient-years of observation. We identified patients in whom methotrexate was re-employed after at least one intermittent course of a different DMARD. We compared reasons for discontinuation, improvement in acute phase reactants, and cumulative retention rates of methotrexate therapy between the original course of methotrexate and its re-employment. Similar analyses were peformed for other DMARDs. Methotrexate was re-employed in 86 patients. Compared with the original courses, re-employment was associated with a reduced risk for treatment termination because of ineffectiveness (P = 0.02, by McNemar test), especially if the maximum methotrexate dose of the original course had been low (<12.5 mg/week; P = 0.02, by logistic regression). In a Cox regression model, re-employed MTX was associated with a significantly reduced hazard of treatment termination compared with the original course of methotrexate, adjusting for dose and year of employment (hazard ratio 0.64, 95% confidence interval 0.42-0.97; P = 0.04). These findings were not recapitulated in analyses of re-employment of other DMARDs. Re-employment of MTX despite prior inefficacy, but not re-employment of other DMARDs, is an effective therapeutic option, especially in those patients in whom the methotrexate dose of the original course was low.     

Postcranial adaptation and evolution in lorisidae

With the exception of leaping, lorises and galagos move in many similar ways although frequencies and styles differ. This peculiar locomotor distinction in two closely related subfamilies has profoundly altered their respective postcranial anatomies from their common ancestor. A comparison of postcranial adaptation in extant forms shows that lorises and galagos differ somewhat in forelimb mobility, but are more fundamentally disparate in hindlimb adaptation. Inferences concerning locomotor adaptation in the lorisid fossil record indicate a more generalized locomotor pattern which is more like that of extant cheirogaleids than either living galagos or lorises. Thus, vertical clinging and leaping in galagines and the slow-climbing and suspensory movements of lorisines appear to be evolutionarily recent innovations from a more generalized locomotor past.