H1° histones of normal and cancer human cells

Summary H1° histones were purified by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis from human lung carcinoma (line DMS79), human hepatoblastoma (HepG2), human adult lung and human adult and fetal liver. The purified human H1° histones were analyzed for their amino acid composition and terminal residues. The comparative analysis of the amino acid compositions of the different human H1° histones showed that: (a) all the H1° preparations have the characteristically high lysine content associated with a low arginine content, which distinguishes outer histones from core histones; (b) H1° is distinguishable from other H1 histones by the presence of methionine and histidine; (c) H1° histones from human adult, fetal and cancer cells are very similar in amino acid composition, and in cancer cells the level of the H1° histone is not inversely related with cell growth rate nor with the expression of the -fetoprotein gene.     

Electronic characterization of the oxidized state of the blue copper protein rusticyanin by 1H NMR: is the axial methionine the dominant influence for the high redox potential?

The oxidized state of rusticyanin, the blue copper protein with the highest redox potential in its class, has been investigated through (1)H nuclear magnetic resonance applied to its cobalt(II) derivative. The assignment of the protons belonging to the coordinated residues has been performed. Many other amino acids situated in the vicinity of the metal ion, including six hydrophobic residues (isoleucine140 and five phenylalanines) have also been identified. The orientation of the main axes of the magnetic susceptibility tensor for the cobalt(II)-rusticyanin as well as its axial, Deltachi(ax), and rhombic, Deltachi(rh), magnetic susceptibility anisotropy components have been determined. A comparison of the present results with those previously obtained for cobalt(II)azurin [Donaire, A., Salgado, J., Moratal, J. M. (1998) Biochemistry 37, 8659-8673] allows us to provide further insights into the reasons for the high redox potential of this protein. According to our results, the interaction between the metal ion and the thioether Sdelta of the axial methionine is not as influential as the strong destabilizing effect that the hydrophobic residues close to the metal ion undergo in the oxidized state.     

Quantification of 1H NMR spectra of human cerebrospinal fluid: a protocol based on constrained total-line-shape analysis

A protocol for quantitative ¹H NMR analysis of human cerebrospinal fluid (hCSF) was built up and assessed as based on Constrained Total-Line-Shape (CTLS) fitting. In this method, linear constraints were applied to spectral structures. The ¹H NMR spectra of 45 human CSF samples were measured and quantified using the CTLS method. The quantification strategies based on total-line-shape fitting are discussed. The metabolic model for CTLS includes 31 metabolites covering 85% of the total spectral intensity, excluding the protein contribution. Prior to data analysis, the data was divided into patients with no Alzheimer’s disease (AD), but with a normal AD marker profile (the peptide β-amyloid₄₂ and tau protein) present in CSF, and into controls that do not have an AD marker profile in CSF. Unexpectedly large variations in metabolite concentrations within the two patient groups were detected, but an analysis of variance revealed a significant (P = 0.027) difference only in the concentration of creatinine which was higher in patients that had a normal AD marker profile. Multivariate classification tools such as self-organizing maps (SOM) failed in separation of the two classes.     

Does intraspecific hybridization contribute to the evolution of invasiveness?: an experimental test

One of the major objectives of research on invasive species is to determine the relative importance of different evolutionary and ecological forces in the invasion process. It was recently suggested that post-introduction intraspecific hybridization between previously isolated genotypes could produce novel and/or heterotic progeny that might express enhanced invasiveness. We tested this hypothesis with Silene latifolia, a European native that has successfully invaded North America and has previously been shown to have undergone genetic change since its introduction. In a common garden experiment we compared the performance of plants derived from within and between population crosses from eight European and 18 North American populations. Results showed that there was no significant effect of crossing distance on progeny phenotype. Furthermore, progeny from within or between population crosses did not differ in size, reproductive output or survival. Collectively, these results suggest that the invasive phenotype of S. latifolia is likely the result of natural selection and/or genetic drift rather than intraspecific hybridization.     

Kinetic analysis of the initial steps involved in lipoplex–cell interactions: effect of various factors that influence transfection activity

We investigated the mode of interaction of lipoplexes (DOTAP:DOPE/DNA) with HeLa cells, focusing on the analysis of the initial steps involved in the process of gene delivery. We evaluated the effect of different factors, namely the stoichiometry of cationic lipids and DNA, the presence of serum in the cell culture medium, and the incorporation of the ligand transferrin into the lipoplexes, on the extent of binding, association and fusion (lipid mixing) of the lipoplexes with the cells. Parallel experiments were performed upon cell treatment with inhibitors of endocytosis. Our results indicate that a decrease of the net charge of the complexes (upon addition of DNA) generally leads to a decrease in the extent of binding, cell association and fusion, except for the neutral complexes. Association of transferrin to the lipoplexes resulted in a significant enhancement of the interaction processes referred to above, which correlates well with the promotion of transfection observed under the same conditions. Besides triggering internalization of the complexes, transferrin was also shown to mediate fusion with the endosomal membrane. The extent of fusion of this type of complexes was reduced upon their incubation with cells in the presence of serum, suggesting that serum components limit the transferrin fusogenic properties. Results were analyzed by using a theoretical model which allowed to estimate the kinetic parameters involved in lipoplex–cell interactions. The deduced fusion and endocytosis rate constants are discussed and compared with those obtained for other biological systems. From the kinetic studies we found a twofold enhancement of the fusion rate constant (f) for the ternary lipoplexes. We also concluded that HeLa cells yield a relatively low rate of endocytosis. Overall, our results estimate the relative contribution of fusion of lipoplexes with the plasma membrane, endocytosis and fusion with the endosomal membrane to their interactions with cells, this information being of crucial importance for the development of gene therapy strategies.     

The mechanism of oxidation-induced low-density lipoprotein aggregation: an analogy to colloidal aggregation and beyond?

Atherosclerosis is a disease initiated by lipoprotein aggregation and deposition in artery walls. In this study, the de novo low-density lipoprotein aggregation process was examined. Nine major intermediates were identified in two stages of the aggregation process. In the aggregation stage, low-density lipoprotein molecules aggregate and form nucleation units. The nucleation units chain together and form linear aggregates. The linear aggregates branch and interact with one another, forming fractals. In the fusion stage, spatially adjacent nucleation units in the fractal fuse into curved membrane surfaces, which, in turn, fuse into multilamellar or unilamellar vesicles. Alternatively, some adjacent nucleation units in the fractals assemble in a straight line and form rods. Subsequently, the rods flatten out into rough and then into smooth ribbons. Occasionally, tubular membrane vesicles are formed from the fractals. The aggregation stage seems to be analogous to colloidal aggregation and amyloid fiber formation. The fusion stage seems to be characteristic of the lipid-rich lipoproteins and is beyond colloidal aggregation and amyloid fiber formation.     

Does the badge of status influence parental care and investment in house sparrows? An experimental test

Theory predicts that traits which signal parental quality might evolve in males of species with biparental care. In avian species, male ornaments may be the most likely candidates for such signals. Male house sparrows (Passer domesticus) possess a black throat patch often referred to as a “badge” or a “badge of status”. By assuming a trade-off between male attractiveness (reflected in male ornaments) and parental care under the differential allocation hypothesis, we predicted that badge size would be negatively correlated with male parental investment. An experiment in which the badge was enlarged in one group and unchanged in a control group was conducted. Our manipulation was predicted to affect female as well as male parental investment. However, we found that eight variables associated with parental investment—the start date for breeding, clutch size, male and female incubation time, male and female food provisioning rate, and average chick weight and the number of fledglings—barely differed between treatments. Also, little evidence for correlations between natural variation in badge size and any of these eight variables was found. Instead, the start date for breeding and the number of fledglings were significantly correlated with both male and female age, while clutch size increased with female age. Female condition was a positive predictor of clutch size and number of fledglings. Female tarsus length, unexpectedly, is related to both male and female incubation time. Badge size was also positively correlated with male age. However, parental age (male or female) was not related to parental care. We conclude that badge size does not signal parental quality, but that the ages of both sexes and the condition of the female play significant roles in the reproductive performance of this species.     

1H NMR metabolomics investigation of an Alzheimer’s disease (AD) mouse model pinpoints important biochemical disturbances in brain and plasma

In this study data generated by ¹H NMR were combined with chemometrics to analyse brain and plasma samples from APP/PS1 and wild type mice with the aim of developing a statistical model capable of predicting the features of Alzheimer’s disease (AD) displayed by this animal model. APP/PS1 is a well characterised double transgenic mouse model of AD and the results here demonstrate the potential of NMR technology as a platform for the detecting this disease. Using partial least squares discriminant analysis a model was built using both brain extracts (R² = 0.99; Q² = 0.66) and a high throughput method of plasma analysis (R² = 0.98; Q² = 0.75) capable of predicting AD in APP/PS1 mice. Analysis of brain extracts led to the elucidation of 20 metabolites and 16 of these were quantifiable. Relative brain levels of ascorbate, creatine, γ-aminobutyric acid and N-acetyl aspartic acid were significantly altered in APP/PS1 mice (p < 0.05). Analysis of plasma identified 14 metabolites and the levels of acetate, citrate, glutamate, glutamine, methionine, and an unknown signal were significantly altered in APP/PS1 mice (p < 0.05). Combining ¹H NMR spectral data with chemometrics has been previously used to study biochemical disturbances in various disease states. This study further indicates the translational potential of this technology for identifying AD in people attending the memory clinic.     

What are the characteristics of lionfish and other fishes that influence their association in diurnal refuges?

In Caribbean reefs, the lionfish Pterois volitans is an invasive species that causes severe negative ecological effects, especially as this crepuscular predator consumes very diverse prey. Lionfish are not active during the day and stay in their refuges, sharing these spaces with various other fishes. The aim of this study is to determine which fishes are associated with the lionfish in their shelters, and what characteristics of both the invasive and native species may influence and explain such coexistence between a predator and its potential prey. Through diving and snorkelling, we visited 141 lionfish refuges, mostly caves, where we observed 204 lionfish and 494 other fish from 16 native species. We recorded species and abundance, as well as lionfish size and abundance. Half of the lionfish were observed in groups and the majority were large-sized. The association with most fish species seems fortuitous, but three species, Gramma loreto, Chromis cyanea and Canthigaster rostrata, were frequently observed in association with lionfish. Numerous fish juveniles, most likely Scarus coeruleus, were also observed together with the invasive predator. The more commonly associated fishes, particularly G. loreto, are mostly associated with large-sized lionfish that were found in groups. The associated fishes are also generally found in groups. Gramma loreto is a potential cleaner of the lionfish; the reasons for the association between these fish species and the invasive lionfish may be more complex than a simple predator-prey relationship and are discussed based on their biological traits and previously reported lionfish trophic ecology and predation behaviour.     

Transhiatal and transthoracic resection in adenocarcinoma of the esophagus: Does the operative approach have an influence on the long-term prognosis?

Background

Goblet cell carcinoid (GCC) of the appendix is a rare neoplasm that share histological features of both adenocarcinoma and carcinoid tumor. While its malignant potential remains unclear, GCC's are more aggressive than conventional carcinoid. The clinical presentations of this neoplasm are also varied. This review summarizes the published literature on GCC of the appendix. The focus is on its diagnosis, histopathological aspects, clinical manifestations, and management.

Methods

Published studies in the English language between 1966 to 2004 were identified through Medline keyword search utilizing terms "goblet cell carcinoid," "adenocarcinoid", "mucinous carcinoid" and "crypt cell carcinoma" of the appendix.

Results

Based on the review of 57 published papers encompassing nearly 600 diagnosed patients, the mean age of presentation for GCC of the appendix was 58.89 years with equal representation in both males and females. Accurate diagnosis of this neoplasm requires astute observations within an acutely inflamed appendix as this neoplasm has a prominent pattern of submucosal growth and usually lacks the formation of a well-defined tumor mass. The mesoappendix was involved in 21.64% followed by perineural involvement in 2.06%. The most common clinical presentations in order of frequency were acute appendicitis in 22.5%; asymptomatic in 5.4%; non-localized abdominal pain in 5.15% and an appendicular mass in 3.09%. The most common surgical treatment of choice was appendectomy with right hemicolectomy in 34.70% followed by simple appendectomy in 24.57%. Concomitant distant metastasis at diagnosis was present in 11.16% of patients with the ovaries being the most common site in 3.60% followed by disseminated abdominal carcinomatosis in 1.03%. Local lymph node involvement was seen in 8.76% of patients at the time of diagnosis. The reported 5-year survival ranges from 60 % to 84%. GCC's of the appendix remains a neoplasm of unpredictable biological behavior and thus warrants lifelong surveillance for recurrence of the disease upon diagnosis and successful surgical extirpation.

Conclusion

GCC of the appendix is a rare neoplasm. Due to its wide range of presentation, this tumor should be considered as a possible diagnosis in many varied situations leading to abdominal surgery. Histopathological features such as increased number of Paneth cells, increased amount of mucin secretion and presence of pancreatic polypeptide may predict a more aggressive behavior. The advocated plan of management recommended for patients with tumors that involve the adjacent caecum or with high-grade tumors with histological features such as an increased mitotic rate involve initial appendectomy with completion right hemicolectomy due to the high possibility of local recurrence with intraperitoneal seeding prior to lymph node involvement and a 20% risk of metastatic behavior. In female patients with GCC of the appendix regardless of age, bilateral salpingo-oophorectomy is advocated. In cases with obvious spread of the disease chemotherapy, mostly with 5-FU and leucovorin is advised. Cytoreductive surgery with adjuvant intraperitoneal chemotherapy can offer improved survival in cases with advanced peritoneal dissemination.     

Physiology and biochemistry of the pseudobranch: an unanswered question?

The structure and function of the pseudobranch has long interested scientists, but its overall role has remained a mystery. Previous studies have attributed respiratory, endocrine, osmoregulatory and sensory roles to the pseudobranch, and the present review concentrates on new findings. Perfusion experiments on the pseudobranch of the rainbow trout (Oncorhynchus mykiss) using both erythrocyte suspensions and Ringer solution have shown that this organ is able to generate values for the respiratory quotient (RQ) greater than 1.0. The release of carbon dioxide into the perfusate was found to be largely independent of flow between perfusion rates of 120-190 microl/min and could be inhibited by acetazolamide (10(-5) M), indicating a role for carbonic anhydrase. Noradrenaline (10(-5) M) had no effect on oxygen consumption or carbon dioxide release of the pseudobranch. The rate of carbon dioxide release was also dependent on the pH of the pre-pseudobranch perfusate, carbon dioxide release being reduced at lower perfusate pH values. Based on the glucose balance of the isolated saline-perfused rainbow trout pseudobranch and on the enzyme profiles for the rainbow trout, cod, swordfish and deep-water grenadier pseudobranch, it is suggested that the pentose phosphate shunt might be a source of carbon dioxide, yielding the high RQ values found for this organ. Most evidence now available indicates that the pseudobranch is integrally linked with the choroid rete and the supply of oxygen to the retina of the fish eye.     

Who Has the Last Laugh? Nanook of the North and Some New Thoughts on an Old Classic

Since its release in 1922 Nanook of the North has remained at the heart of debates in documentary and ethnographic cinema. Long considered a foundational work, Flaherty's film has been hailed and disparaged in equal measure. After an absence of several years, I returned to a viewing of Nanook and found myself surprised by what I saw. Drawing on the work of early cinema historians, I seek here to challenge contemporary critiques and articulate a case for a new reading of the film.