Cancer: a single disease with a multitude of manifestions?

The relationships of critical nutrients such as plant phenolics, vitamins, minerals and lipids are considered with respect to the incidence of a variety of cancers, and analyzed in terms of how these nutrient deficiencies alter immune function, DNA integrity and cell proliferation. With a significant correlation found between cancer and these nutrient deficiencies, the hypothesis is presented here that nutrition could provide a unifying perception of cancer and recast it as a single disease. This further suggests that a coordinated administration of specific, critical nutrients to cancer patients could lead to the reversal of the disease. It is also proposed that the concurrent presence of a variety of nutritional deficiencies in cancer patients requires a multilevel, systemic approach to this disease as opposed to the single active therapeutic agent approach that is the cornerstone of contemporary research and pharmacology.     

Does life originate from a single molecule?

Life did not emerge in a single step. In chemical evolution, the first formation of a self-replicating molecule was probably one of the most critical bottlenecks, which was overcome only with a very low probability. If only one such event was successful, present-day life originates from a single molecule. In this case, homochirality in DNA and RNA is explained almost without further assumptions. By contrast, the enantiomer excess, produced by the deterministic mechanisms suggested so far, is smaller than the statistical standard deviation, unless the postulated initial number of molecules is very--in some mechanisms unreasonably--large. A certain chiral nonuniformity of natural monosaccharides other than (deoxy)ribose supports the idea that homochirality originates not from such small molecules but from an early RNA-like oligomer. This nonuniformity seems also hard to explain by any deterministic mechanism.     

Is there a single biochemical adaptation to anhydrobiosis?

Even though water is required for the maintenance of biologicalintegrity, numerous organisms are capable of surviving lossof virtually all their cellular water and existing in a stateknown as anhydrobiosis. Over the past three decades we and othershave established that disaccharides such as trehalose and sucroseare almost certainly involved in stabilizing the dry cells.We discuss here some of the evidence behind the mechanism ofthis stabilization. Until the past few years this mechanismhas been sufficiently appealing that a consensus has been developingthat acquisition of these sugars in the cytoplasm may be bothnecessary and sufficient for anhydrobiosis. We show here thatthere are other routes to achieve the effects conferred by thesugars and that other adaptations are almost certainly required,at least in environmental conditions that are less than optimal.Under optimal storage conditions, the presence of the sugarsalone may be sufficient to stabilize even mammalian cells inthe dry state, findings that are already finding use in humanclinical medicine.     

Cutting the forest to see a single tree?

The development of single-molecule tools has significantly impacted the way we think about biochemical processes. Watching a single protein in action allows us to observe kinetic details and rare subpopulations that are hidden in ensemble-averaging techniques. I will discuss here the pros and cons of the single-molecule approach in studying ligand binding in macromolecular systems and how these techniques can be applied to characterize the behavior of large multicomponent biochemical systems.     

Influence of a single γ-irradiation on rat microflora

Changes in leukocyte counts and in the gut microflora of laboratory rats irradiated with a single whole-body dose of γ rays (5.0 Gy) were determined. The number of leukocytes was lower especially 1 and 2 weeks after irradiation. A significant decrease in lymphocytes was observed 1 week and in monocytes 1 and 2 weeks after irradiation. In parallel with these changes, an increase in common microflora was observed; some microorganisms, which normally are not present in duodenum, liver and mouth cavity, were detected in these organs.     

Lutzomyia longipalpis in Brazil: a complex or a single species? A mini-review

Lutzomyia longipalpis is the main vector of Leishmania infantum chagasi, the causative agent of American visceral leishmaniasis (AVL). Although there is strong evidence that Lu. longipalpis is a species complex, not all data concerning populations from Brazil support this hypothesis. The issue is still somewhat controversial for this large part of Lu. longipalpis distribution range even though that it is the Latin American region contributing to most of the cases of AVL. In this mini-review we consider in detail the current data for the Brazilian populations and conclude that Lu. longipalpis is a complex of incipient vector species with a complexity similar to Anopheles gambiae s.s. in Africa.     

Does the behavioural activation detected after a single dose of a benzodiazepine reflect a withdrawal response?

The effects, in mice, of a single dose of lorazepam or oxazepam were determined, in the holeboard, 24, 48 and 72 hours after treatment. Lorazepam produced significant increases in both spontaneous locomotor activity and in rearing 48 hours after treatment and oxazepam produced a significant overall increase in rearing over the three time points. There was no detectable in vivo receptor occupancy for either drug at the 48 hour time point, so that these effects were not due to residual concentrations of drug in the brain. We therefore suggest that we were detecting a spontaneous withdrawal response to a single dose of benzodiazepine. The increases in both locomotor activity and rearing, detected 48 hours after lorazepam, could be reversed by treating simultaneously with Ro 15-1788 (a benzodiazepine antagonist). When Ro 15-1788 was injected 20 minutes prior to testing, the mice that had been treated 48 hours previously with lorazepam still showed increased locomotor activity and rearing. We conclude that the hyperactivity was not caused by any change in the levels of endogenous substances acting at the benzodiazepine receptor.     

Interrogation of phosphor-specific interaction on a high-throughput label-free optical biosensor system–Epic® system

The Epic^® system, a high-throughput label-free optical biosensor system, is applied for the biochemical interrogation of phosphor-specific interactions of the 14-3-3 protein and its substrates. It has shown the capability not only for high-throughput characterization of binding rank and affinity but also for the exploration of potential interacting kinases for the substrates. A perspective of biochemical applications for diagnostics and biomarker discovery, as well as cell-based applications for endogenous receptors and viral infection characterization, are also provided.     

Reversal of a reflex to a single motoneuron in the stick insect Çarausius morosus

In inactive stick insects ramp-wise stretching of the femoral chordotonal organ excites the slow extensor tibiae motoneuron. In active animals the same stimulus decreases the firing rate of this motoneuron. The time-course of increased and decreased activity of this motoneuron can be seen with triangular stimulation.Supported by the Deutsche Forschungsgemeinschaft     

The folding of single domain proteins--have we reached a consensus?

Rather than stressing the most recent advances in the field, this review highlights the fundamental topics where disagreement remains and where adequate experimental data are lacking. These topics include properties of the denatured state and the role of residual structure, the nature of the fundamental steps and barriers, the extent of pathway heterogeneity and non-native interactions, recent comparisons between theory and experiment, and finally, dynamical properties of the folding reaction.     

Complementation analysis in Gaucher disease using single cell microassay techniques. Evidence for a single “Gaucher gene”

Gaucher disease is a lysosomal storage disorder resulting from a deficiency of acid beta-glucosidase. Several clinical forms have been described, including infantile, juvenile, and adult onset variant. We have examined complementation in infantile and adult forms of Gaucher disease by monitoring enzyme activity in multinucleate cells produced by fusing skin fibroblasts from different patients in the presence of polyethylene glycol. beta-Glucosidase activity was monitored in lysates of individual multinucleate cells by a microassay method utilizing methylumbelliferyl-beta-D-glucoside as the substrate (normal: 1.3 +/- 0.12 x 10(-13) mol/h/cell). The microassay was linear with time up to 4 h, for up to 20 mononucleate cells, and for individual multinucleate cells containing up to 12 nuclei. Complementation was examined in 11 fibroblasts strains fused in all pairwise combinations. In no instance was there any clear indication of complementation (at least 10-15% of normal activity to adequately account for experimental variation) although there was an indication of marginal increases in some fusions. On the other hand, the expected 50% activity was obtained in "heterozygous" fusions (normal/mutant) for both types of clinical variants. Our results are consistent with a single gene, presumably the structural gene encoding the enzyme, responsible for at least the infantile and adult variants, and confirm the autosomal recessive nature of the disorder.     

Islet1 cardiovascular progenitors: a single source for heart lineages?

The creation of regenerative stem cell therapies for heart disease requires that we understand the molecular mechanisms that govern the fates and differentiation of the diverse muscle and non-muscle cell lineages of the heart. Recently, different cardiac cell types have been reported to arise from a common, multipotent Islet1 (Isl1)-positive progenitor, suggesting that a clonal model of heart lineage diversification might occur that is analogous to hematopoiesis. The ability to isolate, renew and differentiate Isl1(+) precursors from postnatal and embryonic hearts and from embryonic stem cells provides a powerful cell-based system for characterizing the signaling pathways that control cardiovascular progenitor formation, renewal, lineage specification and conversion to specific differentiated progeny.     

Elimination of substrate inhibition of a β-N-acetyl-d-hexosaminidase by single site mutation

Substrate inhibition hinders chitinolytic β-N-acetyl-d-hexosaminidases in producing N-acetyl-d-glucosamine (GlcNAc), the valuable chemical widely applied in medical and food industries. Here we focused on a promising chitinolytic enzyme, OfHex1 from the insect, Ostrinia furnacalis. By structural analysis of OfHex1, five residues nearby the active pocket including V327, E328, Y471, V484 and W490 were chosen and nine mutants including V327G, E328Q, E328A, Y471V, V484R, W490A, W490H, V327G/V484R/W490A and V327G/Y471V/W490H were constructed and recombinantly expressed in Pichia pastoris. The best-performing mutant, W490A, obtained by a higher yield of 5 mg/L, did not show substrate inhibition even when 5 mM of the substrates, (GlcNAc)_2–4, were applied. The k_cat/K_m values for (GlcNAc)_2–4 are 239.8, 111.3 and 79.8 s^?1 mM^?1, respectively. Besides, the pH stability of the mutant ranges from pH 4 to 11 and the thermal stability is up to 50 °C. This work suggests the W490A mutant might be an ideal biocatalyst for GlcNAc production from chitin.     

Modified single node culture method—a new micropropagation method for chickpea

Summary Chickpea was micropropagated by axillary shoot proliferation (ASP) and modified single node culture (MSNC) methods. Maximum propagule proliferation occurred on Murashige and Skoog (MS) medium enriched with 1–10 μM N⁶-benzyladenine and 0.01 μM α-naphthaleneacetic acid. The propagules were rooted on MS medium containing 1 μM 3-indolebutyric acid and B₅ vitamins. Regenerated plants were fertile and phenotypically similar to control plants grown from seed. The MSNC method was four times more efficient than the ASP method in terms of the number of plants produced per explant.     

Physical properties of a single sugar α-linked glucuronic acid-based oligosaccharide produced by a Gluconacetobacter hansenii strain

To date, the physical properties including the morphology, thermal characteristics, and emulsifying activities of a single sugar α-linked glucuronic acid-based water-soluble oligosaccharides (WSOS) produced by Gluconacetobacter hansenii PJK have not been investigated or published elsewhere. Therefore, the current study was undertaken to investigate these important physical properties of WSOS. Field-emission scanning electron microscopy of the WSOS revealed a porous flake-type structure free from adhered bacterial cells. The degradation of the WSOS occurred by four well-differentiated steps with a maximum weight loss (∼40%) in a range of 230–300 °C. The pyrolysis temperature of the WSOS was found to be 278 °C with an enthalpy of 83.01 J/g. The emulsification ability of the WSOS increased initially with concentration, followed by a decrease, and finally became constant. The optimum concentration of WSOS for maximum emulsification (emulsifying ability) was 0.15% (w/v). The emulsions prepared with WSOS did not exhibit significant stability. The formation of oil and aqueous layers was initiated just after 2 min for emulsion prepared with 0.15% (w/v) WSOS, which completely separated after 24 h. It is concluded that WSOS has thermal stability comparable to other microbial polysaccharides. They have moderate emulsification properties, which may be due to the oligomeric nature of WSOS. Additionally the producer organism of WSOS is non-pathogenic. Therefore, the produced WSOS have potential applications in food and/or pharmaceutical preparations and as therapeutic agent in biomedical fields.     

GTP-induced membrane binding and ion channel activity of annexin VI: is annexin VI a GTP biosensor?

Annexin VI (AnxVI) formed ion channels in planar lipid bilayers that were induced by the addition of millimolar guanosine 5'-triphosphate (GTP) at pH 7.4 and that were not accompanied by a penetration of the protein into the membrane hydrophobic region. GTP-influenced interactions of AnxVI with Ca2+/liposomes produced small structural alterations as revealed by circular dichroism and infrared spectroscopies. Guanosine 5'-3-O-(thio)-triphosphate (GTPgammaS) binding to AnxVI, promoted by the photorelease of GTPgammaS from GTPgammaS[1-(4,5-dimethoxy-2-nitrophenyl)-ethyl] (caged-GTPgammaS), affected three to four amino acid residues of AnxVI in the presence of Ca2+/liposomes, while about eight or nine amino acid residues were altered in their absence. This suggested that the nucleotide-binding site overlapped the lipid-binding domain of AnxVI. The binding of the fluorescent GTP analog, 2'-(or 3')-O-(2,4,6-trinitrophenyl)guanosine 5'-triphosphate (TNP-GTP) to AnxVI was optimal in the presence of Ca2+/liposomes, with a dissociation constant (K(d)) of 1 microM and stoichiometry of 1. TNP-GTP promoted fluorescence resonance energy transfer from tryptophan residues to the nucleotide. Ion conductance and fluorescence measurements of the C- and N-terminal fragments of AnxVI indicated distinct GTP-binding properties, suggesting that the existence of the GTP-induced ion channel activity of AnxVI is associated with the flexibility of the two halves of the protein. Such structural flexibility could contribute to a molecular mechanism of AnxVI acting as a GTP biosensor.