Calmodulin concentrates at the apex of growing hyphae and localizes to the Spitzenkörper in Aspergillus nidulans

The calmodulin (CaM) localization pattern in the growing hyphal tip of Aspergillus nidulans was studied with the functional GFP::CaM fusion protein. A faint tip-high gradient of CaM was found in the growing hyphal tip, with CaM highly localized in the region corresponding to the Spitzenkörper forming a bright granule. The position of highly concentrated CaM in the extreme apex seemed to determine the orientation of the hypha. The normal pattern of CaM localization was also shown to be dependent on the integrated actin cytoskeleton. When the growth of the hyphal tip ceased, CaM failed to localize in the bright granule and was evenly distributed in the hyphal tip. These findings suggest that CaM may play an important role in establishing and maintaining apical organization, morphogenesis, and growth in Aspergillus nidulans.

Pressure-induced transition in magnetoresistance of single-walled carbon nanotubes

We applied hydrostatic pressure (up to 10 GPa) to single-walled carbon nanotube bundles at low temperature (down to 2 K) to measure their magnetoresistance (MR) in a field up to 12 T. We found a pressure-induced transition in MR from positive to negative in the high-field regime. The onset of the transition occurs at approximately 1.5 GPa, which correlates closely with the tube shape transitions. The characteristics of the high-pressure MR are consistent with a model of pressure-induced two-dimensional weak localization.

Effects of manganese source and calcium on manganese uptake by in vitro everted gut sacs of broilers' intestinal segments

Three experiments were conducted with everted gut sacs to investigate the effects of Mn source and Ca on Mn absorption in different intestinal segments of broilers. In Experiment 1, the Mn uptake by everted sacs of duodenum, jejunum, and ileum after different incubation times was compared to determine an optimum incubation time. In Experiment 2, 8 different Mn sources, including MnSO4, organic Mn sources (Mn-amino acid chelates, Mn-amino acids complexes with different complex strength), and mixtures of MnSO4 with Gly or Met were used to assess the effect of Mn source on Mn uptake. In Experiment 3, the effect of Ca in media on the uptake of Mn from MnSO4 and Mn-amino acids complexes was investigated. The uptake percentages of Mn by everted ileal sacs were significantly higher than those by duodenal and jejunal sacs. The uptake of Mn as Mn-Met chelate was significantly higher than that of Mn as Mn-Gly chelate. The uptake percentages of Mn as Mn-amino acid complex with moderate complex strength (Mn-AA A) and Mn-amino acid complex with strong complex strength (Mn-AA B) were significantly higher than that of Mn as MnSO4. The uptake of Mn as Mn-AA B by jejunal sacs was significantly higher than that of Mn as Mn-AA A in media containing high level of Ca. The uptake percentages of Mn at high Ca level were significantly higher than those at normal level. The results indicate that when incubated in vitro, ileum was the main site of Mn absorption for broilers. The absorption of Mn as organic sources were higher than that of Mn as inorganic Mn. The absorption of Mn as Mn-AA B with strong complex strength by jejunal sacs was higher than that of Mn as Mn-AA A with moderate complex strength in media containing high level of Ca. As a ligand, Met was more effective in facilitating Mn absorption than Gly. Furthermore, the transportation of Mn through intestinal cells was enhanced by adding Ca as CaCl2 to the buffer solutions.

Quantitative trait loci determining weight reduction of testes and pituitary by diethylstilbesterol in LEXF and FXLE recombinant inbred strain rats

Increasing exposure to environmental endocrine disruptor, xeno-estrogen, is a serious hazard to male reproductive activity. To explore possible genetic control in susceptibility to xeno-estrogen, the weight reduction of testes induced by the continuous administration of a synthetic estrogen, diethylstilbesterol, were investigated by quantitative trait analysis in LEXF and FXLE recombinant inbred strain rats, consisting of 21 independent strains, 9 of their substrains, parental F344/Stm and LE/Stm strains, and (F344 x LE)F1. For the weight of testes, one highly significant quantitative trait locus (QTL) and one significant QTL were mapped on chromosomes 7 and 1, respectively. The QTL on chromosome 7 is closely associated with c-myc. Pituitary weight and serum prolactin were also variable among recombinant inbred strains, but no QTL was detected for them in this study.

Randomized clinical trial of the effects of abdominal drainage after elective hepatectomy using the crushing clamp method

BACKGROUND

Abdominal drainage is a standard procedure after hepatectomy, but this practice has been challenged recently.

METHODS

Between September 2004 and March 2005, 120 consecutive patients who had undergone hepatic resection by the same surgical team were randomly allocated into drainage and no drainage groups (60 in each group). Patient characteristics, preoperative liver function, presence of cirrhosis, resection-related factors and postoperative complications were compared between the two groups.

RESULTS

The groups were comparable in terms of demographics, indications for surgery, preoperative liver function test results, presence of cirrhosis, extent of hepatectomy, intraoperative blood loss and requirement for blood transfusion. Symptomatic subphrenic collection and pleural effusion occurred in four patients (7 per cent) who had abdominal drainage and three (5 per cent) who did not. Local wound complications occurred in 17 (28 per cent) and two (3 per cent) patients respectively (P < 0.001). The postoperative hospital stay was similar in the two groups. Multivariate analysis indicated that the presence of cirrhosis and abdominal drainage were independently related to the development of postoperative wound complications.

CONCLUSION

Routine abdominal drainage is unnecessary after elective hepatectomy using the crushing clamp method.

Comparative proteome analysis of rat brain and coronary microvascular endothelial cells

The endothelium of different organs displays a remarkable heterogeneity, although it presents many common functional and morphological features. However, despite our knowledge of heterogeneity among endothelial cells from different sites, the differences between brain microvascular endothelial cells (BMEC) and coronary microvascular endothelial cells (CMEC) are poorly defined. The aim of this study was to investigate whether BMEC are distinct from CMEC at the protein level. Using the proteomic approach, we comparatively analyzed the proteome of cultured BMEC and CMEC. We reproducibly separated over 2000 polypeptides by using two-dimensional electrophoresis (2-DE) at pH range of 3-10. Using PDQuest software to process the 2-DE gel images, forty-seven protein spots were differentially expressed in the two-endothelial cells. Of these, thirty-five proteins are highly expressed in BMEC, whereas twelve proteins are highly expressed in CMEC. Fifteen proteins in BMEC and seven proteins in CMEC were identified with high confidence by matrix-associated laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS). Our data suggested that BMEC and CMEC were different in several aspects including cytokine and growth-related molecules, stress-related proteins, metabolic enzymes, signal transduction proteins and others. The identification of a set of proteins preferentially expressed in BMEC and CMEC provided new data on the heterogeneity of the endothelium.

BubR1 is involved in regulation of DNA damage responses

Defective mitotic spindles or an impaired spindle-kinetochore interaction activates the spindle checkpoint. We have previously shown that BubR1 haplo-insufficiency results in enhanced genomic instability and tumorigenesis in mice. Here we report that BubR1 deficiency also leads to a compromised response to DNA damage. Following treatment with doxorubicin, BubR1(+/-) murine fibroblast cells (MEF) were defective in undergoing G(2)/M arrest. Thus, whereas in the presence of DNA damage BubR1(+/+) MEF cells remained arrested in mitosis, BubR1(+/-) MEFs rapidly exited from mitosis and divided. The impaired mitotic arrest of BubR1(+/-) MEFs was associated with low levels of phospho-histone H2AX, p53, and p21 after DNA damage caused by treatment with both doxorubicin and ultraviolet light (UV). The impaired expression of p53 and p21 was also confirmed in human cell lines with BubR1 knockdown via RNA interference. Affinity pull-down coupled with mass spectrometry identified Poly(ADP-ribose) polymerase 1 (PARP-1) as one of the proteins interacting with BubR1. Reciprocal co-immunoprecipitation analysis confirmed the physical interaction between BubR1 and PARP-1. Our further study revealed that the ability of retaining intact PARP-1 or its cleavage product p89 was compromised in BubR1(+/-) MEFs upon treatment with doxorubicin or UV. Given that PARP-1 mediates DNA damage responses and regulates the activity of p53, our studies suggest that there exists a cross-talk between the spindle checkpoint and the DNA damage checkpoint and that BubR1 may play an important role in mediating the cross-talk.

Charge-transfer excitations in the model superconductor HgBa(2)CuO(4+delta)

We report a Cu -edge resonant inelastic x-ray scattering (RIXS) study of charge-transfer excitations in the 2-8 eV range in the structurally simple compound HgBa(2)CuO(4+delta) at optimal doping (T(c)=96.5 K). The spectra exhibit a significant dependence on the incident photon energy which we carefully utilize to resolve a multiplet of weakly dispersive (<0.5 eV) electron-hole excitations, including a mode at 2 eV. The observation of this 2 eV excitation suggests the existence of a remnant charge-transfer gap deep in the superconducting phase. Quite generally, our results, which include additional data for the Mott insulator La(2)CuO(4), demonstrate the importance of exploring the incident photon-energy dependence of the RIXS cross section.

Carbidopa pretreatment improves image interpretation and visualisation of carcinoid tumours with 11C-5-hydroxytryptophan positron emission tomography

PURPOSE

Positron emission tomography (PET) with 11C-5-hydroxytryptophan (5-HTP) as tracer is a promising imaging instrument in the management of patients with neuroendocrine tumours (NETs). However, high radioactivity concentrations in the urinary collecting system sometimes produce image reconstruction artefacts that can make detection of small NETs difficult. As a means to decrease urinary excretion of radioactivity and thereby improve image quality, we examined the effect of pretreatment with carbidopa (CD), a peripheral inhibitor of aromatic amino acid decarboxylase (AADC), which converts 5-HTP to serotonin (5-hydroxytryptamine, 5-HT).

METHODS

Six patients with midgut carcinoid metastases were examined with 11C-5-HTP PET before and 1 h after oral administration of 100 or 200 mg of CD.

RESULTS

There was a fourfold significant reduction of tracer uptake in the urinary collecting system after CD administration (p=0.0277, n=6), with a mean standard uptake value (SUV) of 155+/-195 before CD and 39+/-14 after CD. In tumour lesions there was a significant increase in SUV after CD administration (p<0. 0001, n=18), with a mean SUV of 11+/-3 before CD and 14+/-3 after CD. There was no difference between the doses (100 and 200 mg) of CD in this respect. In all patients, image interpretation and tumour detection were markedly improved after CD administration.

CONCLUSION

We conclude that CD premedication improves 11C-5-HTP PET image quality and facilitates detection of NET lesions. Because of the similarity of metabolic pathways, this method could probably be applied to improve PET imaging using other tracers like 18F-DOPA and 11C-DOPA.

Development of a novel protein microarray method for serotyping Salmonella enterica strains

An antibody microarray assay was developed for Salmonella serotyping based on the Kauffmann-White scheme. A model (8 by 15) array was constructed using 35 antibodies for identification of 20 common Salmonella serovars and evaluated using 117 target and 73 nontarget Salmonella strains. The assay allowed complete serovar identification of 86 target strains and partial identification of 30 target strains and allowed exclusion of the 73 nontarget strains from the target serovars.

Effect of mutation of amino acids 246-251 (KRKHKK) in HSP72 on protein synthesis and recovery from hypoxic injury

Heat shock protein (HSP)72, the inducible form of HSP70, protects cells against a variety of injuries, but underlying mechanisms are poorly defined. To investigate the protective effects of HSP72, multiple clones expressing wild-type (WT) HSP72 and two mutants with defective nucleolar and nuclear localization (M45 and 985A, respectively) were made with the tet-off system in C2C12 cells. Four different parameters of cell function/injury were examined after simulated ischemia: protein synthesis, polysome formation, DNA synthesis, and lactate dehydrogenase (LDH release). Overexpression of WT HSP72 was also compared to nontransfected C2C12 cells. As expected, overexpression of HSP72 protected against simulated ischemia and reoxygenation for all parameters. In contrast, both M45 and 985A showed abnormal protein synthesis and polysome formation, both after simulated ischemia and under control conditions. Total RNA was slightly reduced in M45 and 985A at baseline, but 1 h after hypoxia, RNA levels were protected in all clones but significantly decreased in nontransfected C2C12 cells. Clones expressing 985A had nuclear retention of mRNA, suggesting that HSP72 is needed for nuclear export of RNA. All clones, both WT and mutant, had protection of DNA synthesis compared to C2C12 cells, but 985A had greater release of LDH after injury than any other group. These results support a multifactoral protective effect of HSP72, some aspects dependent on nuclear localization with stress and some not. The protection of protein synthesis and polysome formation, and abnormalities in these with the mutants, support a role for HSP72 in these processes both in the normal cell and in injury.