Polymorphism of DNA Repair Gene xrcc1 and Lung Cancer Risk

The current large-scale meta-analysis was performed to reach a reliable conclusion on the association between X-ray repair cross-complementing 1 (xrcc1) rs1799782 and the development of lung cancer. Studies that investigated the association between rs1799782 and lung cancer risk were identified by searching PubMed. We calculated odds ratio (OR) with corresponding 95 % confidence interval (CI) for Trp/Trp vs Arg/Arg, Trp/Trp + Arg/Trp vs Arg/Arg, and Trp/Trp vs Arg/Trp + Arg/Arg contrast models. Combining all 25 studies, we yielded three summary ORs: 1.07 (95 % CI 0.92–1.23) for Trp/Trp vs Arg/Arg, 0.93 (95 % CI 0.87–1.00) for Trp/Trp + Arg/Trp vs Arg/Arg, and 1.08 (95 % CI 0.94–1.25) for Trp/Trp vs Arg/Trp + Arg/Arg, suggesting rs1799782 was not associated with overall risk of lung cancer. Strikingly, a significantly deceased risk was found among Caucasian populations (Trp/Trp + Arg/Trp vs Arg/Arg, OR = 0.86, 95 % CI 0.76–0.97). This study confirms that xrcc1 rs1799782 may lower the risk of lung cancer among Caucasians.     

Identification of nucleolus-localized PTEN and its function in regulating ribosome biogenesis

The tumor suppressor PTEN is a lipid phosphatase that is found mutated in different types of human cancers. PTEN suppresses cell proliferation by inhibiting the PI3K-Akt signaling pathway at the cell membrane. However, PTEN is also demonstrated to localize in the cell nucleus where it exhibits tumor suppressive activity via a different, unknown mechanism. In this study we report that PTEN also localizes to the nucleolus and that nucleolar PTEN plays an important role in regulating nucleolar homeostasis and maintaining nucleolar morphology. Overexpression of nuclear PTEN in PTEN null cells inhibits Akt phosphorylation and reduces cell size. Knockdown of PTEN in PTEN positive cells leads to nucleolar morphologic changes and an increase in the proportion of cells with a greater number of nucleoli. In addition, knockdown of PTEN in PTEN positive cells increased ribosome biogenesis. These findings expand current understanding of function and relevance of nuclear localized PTEN and provide a foundation for the development of novel therapies targeting PTEN.     

Quercetin Potentiates the Antitumor Activity of Rituximab in Diffuse Large B-Cell Lymphoma by Inhibiting STAT3 Pathway

STAT3 pathway plays an important role in the growth of diffuse large B-cell lymphoma (DLBCL) cells. Here we investigated the antitumor activity of Quercetin, a flavonoid compound, in combination with rituximab in DLBCL cell lines in vitro. We found that Quercetin synergistically enhanced rituximab-induced growth inhibition and apoptosis in DLBCL cell lines. Moreover, we found Quercetin exerted inhibitory activity against STAT3 pathway and downregulated the expression of survival genes. These results suggest that combining the Quercetin with rituximab may present an attractive and potentially effective way for the treatment of DLBCL.     

On the existence of two GABA pools associated with newly synthesized GABA and with newly taken up GABA in nerve terminals

[¹⁴C]Glutamic acid and [³H]GABA were injected into the lateral ventricle of mouse and then [¹⁴C]GABA and [³H]GABA in synaptosomes isolated from the animals were analysed. The [¹⁴C]GABA was interpreted to be newly synthesized GABA from [¹⁴C]glutamic acid while the [³H]GABA to be newly taken up GABA. We have obtained the following results: (1) when the animals were pretreated with aminooxyacetic acid and thus the GABA content in synaptosomes increased to about 2 times of the control level, only the [³H]GABA was enhanced to 3 times of the control level without any change of [¹⁴C]GABA, (2) the release of [¹⁴C]GABA from synaptosomes by high K⁺ depolarization was 1.5 times greater than that of [³H]GABA, (3) the releases of both [¹⁴C]GABA and [³H]GABA were increased in the presence of cold GABA,l-2,4-diaminobutyric acid or γ-amino-β-hydroxybutyric acid, but only slightly increased in the presence of β-alanine. These results would suggest that newly synthesized GABA and newly taken up GABA localized individually in different pools, which might localize either in different nerve terminals or separately in the same nerve terminal.     

A genetic and ultrastructural study of three clones of Porphyridium purpureum (Bory de Saint-Vincent, 1797) Drew et Ross, 1965 (Rhodophyta) from the marine microalgae collection of the Zhirmunsky institute of marine biology

In this paper, we present the results of a comparative genetic and ultrastructural study of three clones of the microalga Porphyridium purpureum (Rhodophyta) from the culture collection of marine microalgae of the Zhirmunsky Institute of Marine Biology. All clones, which have different geographical origins, showed a high similarity in terms of the ultramicroscopic structure and the nucleotide sequences of the nuclear ribosomal DNA genes (18S rDNA, ITS1-5.8S rDNA-ITS2, D1-D2 region of 28S rDNA). The obtained data are very helpful for the certification of two strains of P. purpureum that were isolated for the first time in the practice of Russian algological research.     

Immune Response of the VEGF/bFGF Complex Peptide Vaccine and Function of Immune Antibodies in Inhibiting Migration of HUVEC Cells and Proliferation of Cancer Cells

Overexpression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis and metastasis in tumors. VEGF/bFGF complex peptide (VBP3) was designed to elicit the body to produce both high titer anti-VEGF and anti-bFGF antibodies to inhibit tumor angiogenesis and tumor growth. BALB/c mice were immunized with the VEGF/bFGF complex peptide, and the immune responses were assayed. Splenocytes were separated from the immunized mice and the CD4, CD8 T cells and IFN-γ were assayed by Flow cytometry. The results showed that the VBP3 could effectively stimulate immune response in mice and resulted in the increase of CD4 and CD8 T cells. CD4+ T cells and CD8+ T cells were increased from 10.78 to 15.13 and 6.82 to 11.58 % respectively. Polyclonal antibodies purified from the VBP3 immunized mice showed good anti-proliferation function to lung cancer cells, and resulted in the decrease of phosphroylation level of Akt and Erk assayed by the Western-blot. Transwell assays showed that the migration of HUVEC cells was inhibited by the antibodies. The results revealed that the VBP3 have good immunogenicity and may be used as a vaccine for tumor therapy.     

The amino-terminal sequence ofStreptomyces griseus carboxypeptidase

The amino-terminal sequence of carboxypeptidase fromStreptomyces griseus was determined using a new protocol for automatic Edman degradation that reduced background noise. The sequence of the first 48 residues is: Asp-Phe-Pro-Pro-Ala-Asp-Ser-Arg-Tyr-His-Asn-Tyr-Ala-Glu-Met-Asn-Ala-Ala-Ile-Asp-Ala-Arg-Ile-Ala-Ala-Asn-Pro-Ser-Ile-Met-Ser-Lys-Arg-Val-Ile-Gly-Lys-Thr-Tyr-Gln-Gly-(Arg)-Asp-Val-Ile-Ala-Val-Lys, which is homologous to that of other zinc-containing carboxypeptidase from vertebrate and invertebrate sources.     

Leaf flavonoids ofGalium sect.Aparinoides (Rubiaceae)

13 taxa belonging to 4 “species groups” ofGalium L. sect.Aparinoides (Jord.)Gren. produce 15 leaf flavonoids: Apigenin-7-diglucoside, Luteolin-7-monoglucoside and 7-diglucoside, Diosmetin, Diosmetin-7-monoglucoside and 7-diglucoside; Kaempferol-3-rutinoside, Kaempferol-3,7-diglucoside, Quercetin, two Quercetin-3-monoglycosides, Rutin, Quercetin-3-rutinoside-7-glucoside, Quercetin-7-glycoside and an unidentified aglycone. TheG. trifidum, G. obtusum andG. palustre groups (with the exception of theG. tinctorium subspecies andG. elongatum) have similar flavone-flavonole patterns, while theG. antarcticum group produces a specific pattern. Leaf flavonoids of theG. trifidum andG. antarcticum group are inhomogenous, becauseG. tinctorium subsp.tinctorium andG. antarcticum lack flavones. For all taxa (with the exception of those of theG. antarcticum group) intraspecific variation is demonstrated, and 4 populations ofG. trifidum subsp.trifidum, G. tinctorium subsp.tinctorium,G. obtusum subsp.obtusum andG. labradoricum even exhibit intrapopulation variation. The implications of flavonoid data on the systematics and the astonishing intrapopulation and intraspecific variation are discussed.     

Unit responses of the second auditory area to acoustic stimulation

Responses of 116 neurons of the second auditory area to clicks were recorded extracellularly in experiments on unanesthetized cats immobilized with D-tubocurarine. Neurons with and without (54.6%) took part in the response to clicks. The unit response to a click consisted of 1 or 2 spikes or a short volley. Different neurons responded to clicks at different times. The latent period of 25.8% of all neurons recorded was 6.5–13 msec, of 70% it was 14–25 msec, and of 4.2% it was over 25 msec. Long-latency responses to clicks (40, 50, and 100 msec) also were recorded. The responding neurons were found throughout the thickness of the cortex, but more frequently in layers III and IV. No relationship was found between the depth of the neuron and its latest period. Responses consisting of EPSP, EPSP-spike, EPSP-spike-IPSP, EPSP-IPSP, and primary IPSP were recorded intracellularly from the neurons of this area. It was concluded from the results that neurons of the second auditory area can be activated by the arrival of an afferent volley along the geniculo-cortical pathway and also by the arrival of impulses from the first auditory area.     

Quantitative and Multiplexed Study of Endothelial Cell Inflammation

Endothelial inflammation plays major roles in all phases of the atherosclerotic process, the leading cause of death by cardiovascular disease. Both innate immunity and endothelial adhesion molecules contribute to endothelial inflammation. In this work, we applied multiple antibodies (Abs) to measure changes in expression levels of six proteins in response to inflammatory stimulation. These six proteins include toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) representing innate immunity and four endothelial adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), E-selectin, and P-selectin. We observed two different types of dynamic behaviors among these proteins upon inflammatory stimulation. Increased expression of toll-like receptor 2 (TLR2), P-selectin, E-selectin, and TLR4 peaked relatively early (after 4 h of stimulation) while VCAM-1, and ICAM-1 showed a more gradual and consistent increase in expression with stimulatory time. The magnitude of this increase was significantly greater for VCAM-1 and ICAM-1. The multiplexed detection developed in this study using fluorophore-conjugated primary Abs provides an approach for live cell and in vivo imaging of endothelium inflammation for quantitative characterization of multiple proteins within a network.     

Genetic basis for the polymorphism of rat liver cytosolic aldehyde dehydrogenase

Liver aldehyde dehydrogenase (ALDH), the enzyme involved in the oxidation of aldehydes such as acetaldehyde derived from ethanol, exists in multiple forms in most mammals. Up to five separable forms have been identified from the cytosolic fraction of Wistar rat liver. We investigated the genetic basis of a particular set of three enzyme forms by selective breeding and analysis of electrophoretic patterns of liver ALDH by isoelectric focusing. The forms of liver ALDH investigated were at pI 5.8 or 6.2, or a triple form with enzymes at pI 5.8, 6.0, and 6.2. There are two alleles found at the ALDH locus which encode in homozygotes for one of two electrophoretically separable ALDH forms. A rat heterozygous at the locus forms both ALDH types plus a hybrid. The alleles are expressed codominantly, found at an autosomal locus, and remain constant postpartum. The activities associated with the triplet enzyme form were statistically indistinguishable from a 1:2:1 ratio. This suggests that the enzymes hybridize to form a set of dimers or tetramers of the form A₂, AB, B₂ or A₄, A₂B₂, B₄, respectively.     

Location of the genes coding for 18S and 28S ribosomal RNA in the human genome

³H-rRNA obtained from Xenopus laevis tissue cultured cells, or a ³H-cRNA made from Xenopus ribosomal DNA, was used for heterologous in situ hybridisation with human lymphocyte metaphase chromosomes. Prior to hybridisation, chromosome spreads were stained with Quinacrine and selected cells showing good Q-banding photographed; the same cells were then rephotographed after autoradiography and pairs of photographs for each cell were used to make dual karyotypes. The chromosomes within each karyotype were divided into equal sized segments (approx. 0.7 μ), with a fixed number of segments for each chromosome type. The distribution of silver grains between segments showed that the ³H-RNAs hybridised specifically to the nucleolar organising regions of the D and G group chromosomes with no other sites of localised labelling in the complement. Control experiments showed no localisation, with insignificant labelling, when metaphase spreads were incubated in a mixture containing Xenopus ³H-rRNA and competing cold human (HeLa) rRNA. Filter hybridisation experiments on isolated human DNA showed that the Xenopus derived ³H-RNAs hybridised to a fraction of human DNA which was on the heavy side of the main DNA peak and that these RNAs were competed out in the presence of excess cold human rRNA, confirming the specificity of the heterologous hybridisation. In situ hybridisation experiments were also carried out on cells from individuals with one chromosome pair showing heteromorphism for either a very long stalk (nucleolar constriction) subtending a satellite, or a large satellite. It was shown that the chromosome with the large stalk hybridised four times as much ³H-rRNA as its homologue, whereas differences in the sizes of the subtended satellites did not materially affect hybridisation levels indicating that rDNA is located in the stalks and not the satellites. The amount of ³H-rRNA hybridised differs between chromosomes and individuals; these differences are heritable and rDNA can be detected by in situ hybridisation in all three chromosomes number 21 in cells from Down's patients and in translocated chromosomes conta.ining a nucleolar constriction. Different D and G group chromosomes which hybridised equal amounts of ³H-rRNA participated in rosette associations at metaphase in a random fashion in some individuals and in a non-random fashion in others. In all individuals studied chromosomes with large amounts of rDNA were not found to be preferentially involved in association. It was therefore concluded that the probability of a chromosome being involved in the formation of a common nucleolus is not a simple function of its rDNA content and other possible factors are considered.     

A new model for the calcification of the green macro-alga Halimeda opuntia (Lamouroux)

Halimeda opuntia is a cosmopolitan marine calcifying green alga in shallow tropical marine environments. Besides Halimeda’s contribution to a diverse habitat, the alga is an important sediment producer. Fallen calcareous segments of Halimeda spp. are a major component of carbonate sediments in many tropical settings and play an important role in reef framework development and carbonate platform buildup. Consequently the calcification of H. opuntia accounts for large portions of the carbonate budget in tropical shallow marine ecosystems. Earlier studies investigating the calcification processes of Halimeda spp. have tended to focus on the microstructure or the physiology of the alga, thus overlooking the interaction of physiological and abiotic processes behind the formation of the skeleton. By analyzing microstructural skeletal features of Halimeda segments with the aid of scanning electron microscopy and relating their occurrence to known physiological processes, we have been able to identify the initiation of calcification within an organic matrix and demonstrate that biologically induced cementation is an important process in calcification. For the first time, we propose a model for the calcification of Halimeda spp. that considers both the alga’s physiology and the carbon chemistry of the seawater with respect to the development of different skeletal features. The presence of an organic matrix and earlier detected external carbonic anhydrase activity suggest that Halimeda spp. exhibit biotic precipitation of calcium carbonate, as many other species of marine organisms do. On the other hand, it is the formation of micro-anhedral carbonate through the alga’s metabolism that leads to a cementation of living segments. Precisely, this process allows H. opuntia to contribute substantial amounts of carbonate sediments to tropical shallow seas.     

Genetic variation in the activity of the histidine catabolic enzymes between inbred strains of mice: A structural locus for a cytosol histidine aminotransferase isozyme (Hat-1)

Variation in activity of the main histidine catabolic enzymes (histidase, urocanase, and aminotransferase) has been surveyed using inbred strains of mice (C57BL, DBA, Peru, SM, and SWR). Some variation was found in the activity of all enzymes, but only in the case of cytosolic histidine aminotransferase was it greater than twofold (SM 3.3-fold greater than C57BL). The divergent strains for the activity of this enzyme were crossed and the F ₁ 's were backcrossed; the segregation analysis indicated a single locus with additively acting alleles (designated Hat-1: a allele SM, b allele C57BL). Cytosolic histidine aminotransferase differed in heat stability between SM and C57BL, indicating that Hat-1 is a structural locus. The conflict in the biochemical literature (Morris et al., 1973; Noguchi et al., 1976a, b) over the number and subcellular distribution of the histidine aminotransferase isozymes is partly resolved by the acquisition of a variant at the Hat-1 locus. Hat-1 affects the cytosolic form but not the mitochondrial form of the enzyme. Purification and analysis of the isozymes of histidine aminotransferase from livers of C57BL and SM mice will further clarify the situation.