Apoptosis is required during early stages of tail regeneration in Xenopus laevis

The Xenopus tadpole is able to regenerate its tail, including skin, muscle, notochord, spinal cord and neurons and blood vessels. This process requires rapid tissue growth and morphogenesis. Here we show that a focus of apoptotic cells appears in the regeneration bud within 12 h of amputation. Surprisingly, when caspase-3 activity is specifically inhibited, regeneration is abolished. This is true of tails both before and after the refractory period. Programmed cell death is only required during the first 24 h after amputation, as later inhibition has no effect on regeneration. Inhibition of caspase-dependent apoptosis results in a failure to induce proliferation in the growth zone, a mispatterning of axons in the regenerate, and the appearance of ectopic otoliths in the neural tube, in the context of otherwise normal continued development of the larva. Larvae amputated during the refractory stage exhibit a much broader domain of caspase-3-positive cells, suggesting a window for the amount of apoptosis that is compatible with normal regeneration. These data reveal novel roles for apoptosis in development and indicate that a degree of apoptosis is an early and obligate component of normal tail regeneration, suggesting the possibility of the existence of endogenous inhibitory cells that must be destroyed by programmed cell death for regeneration to occur.     

Pannexin1 is part of the pore forming unit of the P2X(7) receptor death complex

The purinergic receptor P2X(7) is part of a complex signaling mechanism participating in a variety of physiological and pathological processes. Depending on the activation scheme, P2X(7) receptors in vivo are non-selective cation channels or form large pores that can mediate apoptotic cell death. Expression of P2X(7)R in Xenopus oocytes results exclusively in formation of a non-selective cation channel. However, here we show that co-expression of P2X(7)R with pannexin1 in oocytes leads to the complex response seen in many mammalian cells, including cell death with prolonged ATP application. While the cation channel activity is resistant to carbenoxolone treatment, this gap junction and hemichannel blocking drug suppressed the currents induced by ATP in pannexin1/P2X(7)R co-expressing cells. Thus, pannexin1 appears to be the molecular substrate for the permeabilization pore (or death receptor channel) recruited into the P2X(7)R signaling complex.     

hPEBP4 resists TRAIL-induced apoptosis of human prostate cancer cells by activating Akt and deactivating ERK1/2 pathways

The treatment options available for prostate cancer are limited because of its resistance to therapeutic agents. Thus, a better understanding of the underlying mechanisms of the resistance of prostate cancer will facilitate the discovery of more efficient treatment protocols. Human phosphatidylethanolamine-binding protein 4 (hPEBP4) is recently identified by us as an anti-apoptotic molecule and a potential candidate target for breast cancer treatment. Here we found the expression levels of hPEBP4 were positively correlated with the severity of clinical prostate cancer. Furthermore, hPEBP4 was not expressed in TRAIL-sensitive DU145 prostate cancer cells, but was highly expressed in TRAIL-resistant LNCaP cells, which show highly activated Akt. Interestingly, hPEBP4 overexpression in TRAIL-sensitive DU145 cells promoted Akt activation but inhibited ERK1/2 activation. The hPEBP4-overexpressing DU145 cells became resistant to TRAIL-induced apoptosis consequently, which could be reversed by PI3K inhibitors. In contrast, silencing of hPEBP4 in TRAIL-resistant LNCaP cells inhibited Akt activation but increased ERK1/2 activation, resulting in their sensitivity to TRAIL-induced apoptosis that was restored by the MEK1 inhibitor. Therefore, hPEBP4 expression in prostate cancer can activate Akt and deactivate ERK1/2 signaling, leading to TRAIL resistance. We also demonstrated that hPEBP4-mediated resistance to TRAIL-induced apoptosis occurred downstream of caspase-8 and at the level of BID cleavage via the regulation of Akt and ERK pathways, and that hPEBP4-regulated ERK deactivation was upstream of Akt activation in prostate cancer cells. Considering that hPEBP4 confers cellular resistance to TRAIL-induced apoptosis and is abundantly expressed in poorly differentiated prostate cancer, silencing of hPEBP4 suggests a promising approach for prostate cancer treatment.     

Single feature polymorphism discovery in rice

The discovery of nucleotide diversity captured as single feature polymorphism (SFP) by using the expression array is a high-throughput and effective method in detecting genome-wide polymorphism. The efficacy of such method was tested in rice, and the results presented in the paper indicate high sensitivity in predicting SFP. The sensitivity of polymorphism detection was further demonstrated by the fact that no biasness was observed in detecting SFP with either single or multiple nucleotide polymorphisms. The high density SFP data that can be generated quite effectively by the current method has promise for high resolution genetic mapping studies, as physical location of features are well-defined on rice genome.     

Breeding and application of Jiafuzhan, a new elite early indica rice cultivar in China

After 20 years of dedicated research,Jiafuzhan has been successfully developed under the new technologies in breeding high-quality early indica rice cultivars.Its rice quality has almost reached the A-level Editable Rice of Agriculture Department of China,and its average production reaches 400-500 kg/(666.7 m2).This new cultivar also has other characteristics such as enhanced resistance of blast and fallen,steady productivity,and strong adaptability.Jiafuzhan has been put into production of over 11.4×104 hm2 in Fujian Province and has been introduced and extended in other Provinces like Jiangxi,Guangdong,and Guangxi,China.The successes of breeding Jiafuzhan is a solution to the existing perennial problems in the rice industry,such as poor grain quality of big-grain rice and early indica rice,low productivity,and poor blast resistance of elite rice.     

A method for the identification of glycoproteins from human serum by a combination of lectin affinity chromatography along with anion exchange and Cu-IMAC selection of tryptic peptides

This paper reports a method for identifying glycoproteins from human serum. Glycoproteins were selected with a concanavalin A (Con A) lectin column and then tryptically digested prior to sequential chromatographic selection of acidic and histidine containing peptides. Acidic peptides were selected with a strong anion exchange (SAX) column. Peptides captured by the SAX columns were then released and histidine-containing peptides in the mixture selected with a copper loaded immobilized metal affinity chromatography (Cu-IMAC) column. This serial chromatographic selection process reduced the complexity of proteolytic digests by more than an order of magnitude. Peptides selected by this serial process were then fractionated by reversed-phase chromatography (RPC) and identified by tandem mass spectrometry. The method was initially validated using human transferrin before application to human serum. The results show that all the peptides identified except one contained histidine and acidic amino acids.     

Analysis of mouse skin reveals proteins that are altered in a diet-induced diabetic state: a new method for detection of type 2 diabetes

In this study, proteomic analysis was performed on the skin of C57BL/6J mice with type 2 diabetes and compared to nondiabetic controls. To induce obesity and subsequent diabetes, mice were placed on a high-fat diet for 16 wk. After 16 wk, both diabetic and nondiabetic control mice were sacrificed and their skin removed for analysis. Following 2-DE, proteomic profiles from the skin samples were quantified using PDQuest software. Out of more than 1000 distinct protein spots, 28 were shown to be significantly altered with 6 being decreased and 22 increased in the diabetic state compared to controls. The 28 protein spots were removed from the gels and analyzed by MALDI-TOF and MS/MS analyses. Protein identifications revealed that 17 of the 28 proteins were involved in energy metabolism (60.7% of changes observed). Collectively, none of the significantly altered proteins had been shown previously to be altered in diabetic skin. This study not only helps to identify proteins found in skin samples of obese mice with type 2 diabetes, but also shows that skin biopsies coupled with proteomic analysis may be useful as a noninvasive method for the diagnosis of hyperinsulinemia and diabetes.     

Conserved processes and lineage-specific proteins in fungal cell wall evolution

The cell wall is a defining organelle that differentiates fungi from its sister clades in the opisthokont superkingdom. With a sensitive technique to align low-complexity protein sequences, we have identified 187 cell wall-related proteins in Saccharomyces cerevisiae and determined the presence or absence of homologs in 17 other fungal genomes. There were both conserved and lineage-specific cell wall proteins, and the degree of conservation was strongly correlated with protein function. Some functional classes were poorly conserved and lineage specific: adhesins, structural wall glycoprotein components, and unannotated open reading frames. These proteins are primarily those that are constituents of the walls themselves. On the other hand, glycosyl hydrolases and transferases, proteases, lipases, proteins in the glycosyl phosphatidyl-inositol-protein synthesis pathway, and chaperones were strongly conserved. Many of these proteins are also conserved in other eukaryotes and are associated with wall synthesis in plants. This gene conservation, along with known similarities in wall architecture, implies that the basic architecture of fungal walls is ancestral to the divergence of the ascomycetes and basidiomycetes. The contrasting lineage specificity of wall resident proteins implies diversification. Therefore, fungal cell walls consist of rapidly diversifying proteins that are assembled by the products of an ancestral and conserved set of genes.