Selenium salts and chromosome damage

Sodium selenite and sodium selenate, fed by gavaging to age-matched male Swiss albino mice and observed after 24 h following a colchicine-fixative-air drying-Giemsa schedule, were found to induce chromosome breaks and spindle disturbances in bone marrow cells. The four concentrations used were fractions of LD₅₀ and the effects were directly proportionate to the concentration of the chemical. Sodium selenite induced a slightly higher frequency of chromosomal aberrations than sodium selenate.     

A comparison of pinewood and moorland soils in the Abernethy Forest Reserve, Scotland

Despite considerable published literature on the above-ground ecology of the pinewoods of Scotland, little research has considered the way in which pinewood soils differ from those under other vegetation types. Soil properties were compared between ancient, semi-natural Scots pine forest and moorland on three soil types in the Abernethy Forest Reserve in the Cairngorm Mountains of Scotland. Soil morphology differed considerably between the vegetation types on each soil type, principally in the thickness of organic layers. Forest soils had thicker organic layers and this was particularly true of the F horizon. Forest soils were slightly less acid than equivalent moorland soils and had accumulated significantly more carbon. Forest soils in this environment therefore have the capacity to sequester larger amounts of carbon than moorland, and therefore represent a significant potential carbon sink. The quantity of nitrogen and phosphorus was also consistently larger in the organic layers under pine forest and since little difference existed in these properties in the mineral horizons, it was concluded that this accumulation was real and represented a net addition to the tree-soil system.     

Comparison of clastogenic effects of inorganic selenium salts in mice in vivo as related to concentrations and duration of exposure

Inorganic selenium compounds in the diet have been known to protect against cancer in laboratory animals, but were harmful in high concentrations. In the present work, the relative effects of two salts, sodium selenite and sodium selenate, administered to mice in vivo, in different concentrations and durations of exposure, were compared. Aqueous solutions of each salt (7, 14, 21 and 28 mg Kg^–1 bw) were fed by gavaging to mice matched in age and sex. The animals were sacrificed at intervals of 6, 12, 18 and 24 h and chromosome preparations were made following the usual schedule of colchicine-hypotonic-fixative-airdrying-Giemsa staining. The endpoints screened were chromosomal aberrations (CA) and damaged cells (DC). Both salts affected chromosome structure and spindle formation, sodium selenite being more cytotoxic than sodium selenate. The frequencies of aberrations induced were directly proportional to the concentrations used and duration of exposure.     

Excess mortality in persons with severe mental disorders: a multilevel intervention framework and priorities for clinical practice,policy and research agendas

Excess mortality in persons with severe mental disorders (SMD) is a major public health challenge that warrants action. The number and scope of truly tested interventions in this area remain limited, and strategies for implementation and scaling up of programmes with a strong evidence base are scarce. Furthermore, the majority of available interventions focus on a single or an otherwise limited number of risk factors. Here we present a multilevel model highlighting risk factors for excess mortality in persons with SMD at the individual, health system and socio‐environmental levels. Informed by that model, we describe a comprehensive framework that may be useful for designing, implementing and evaluating interventions and programmes to reduce excess mortality in persons with SMD. This framework includes individual‐focused, health system‐focused, and community level and policy‐focused interventions. Incorporating lessons learned from the multilevel model of risk and the comprehensive intervention framework, we identify priorities for clinical practice, policy and research agendas.     

Organic Matter Stimulates Bacteria and Arbuscular Mycorrhizal Fungi in Bauhinia purpurea and Leucaena diversifolia Plantations on Eroded Slopes in Nepal

Erosion resulting from landslides is a serious problem in mountainous countries such as Nepal. To restore such sites it is essential to establish plant cover that protects the soil and reduces surface erosion. Mycorrhizal fungi growing in symbiosis with plants are essential in this respect because they improve both plant nutrient uptake and soil structure. We investigated the influence of organic matter and P amendment on recently produced biomass of bacteria and arbuscular mycorrhizal (AM) fungi in eroded slopes in Nepal. Eroded soil mixed with different types of organic matter or P was placed in mesh bags, which were buried around trees of Bauhinia purpurea and Leucaena diversifolia between June 2003 and December 2003 (the wet season) or between December 2003 and June 2004 (the dry season). Signature fatty acids were used to determine bacterial and AM fungal biomass after the 6‐month intervals. The amount and composition of AM fungal spores were analyzed in the mesh bags from the dry season. More microbial biomass was produced during the wet season than during the dry season. Furthermore, organic matter addition enhanced the production of AM fungal and bacterial biomass during both periods. The positive influence of organic matter addition on AM fungi could be an important contribution to plant survival in plantations on eroded slopes. Different AM spore communities and bacterial profiles were obtained with different organic amendments and this suggests a possible way of selecting for specific microbial communities in the management of eroded sites.     

The influence of substituents (R) at N atom of thiophene-2-carbaldehyde thiosemicarbazones {(C4H3S)HCN-N(H)-C(S)NHR} on bonding, nuclearity and H-bonded networks of copper(I) complexes

The nuclearity, bonding and H-bonded networks of copper(I) halide complexes with thiophene-2-carbaldehyde thiosemicarbazones {(C₄H₃S)HC²N³-N(H)-C¹(S)N¹HR} are influenced by R substituents at N¹ atom. Thiophene-2-carbaldehyde-N¹-methyl thiosemicarbazone (HttscMe) or thiophene-2-carbaldehyde-N¹-ethyl thiosemicarbazone (HttscEt) have yielded halogen-bridged dinuclear complexes, [Cu₂(μ-X)₂(η¹-S-Htsc)₂(Ph₃P)₂] (Htsc, X: HttscMe, I, 1; Br, 2; Cl, 3; HttscEt, I, 4; Br, 5; Cl, 6), while thiophene-2-carbaldehyde-N¹-phenyl thiosemicarbazone (HttscPh) has yielded mononuclear complexes, [CuX(η¹-S-HttscPh)₂] (X, I, 7a; Br 8; Cl, 9) and a sulfur bridged dinuclear complex, [Cu₂(μ-S-HttscPh)₂(η¹-S-HttscPh)₂I₂] 7b co-existing with 7a in the same unit cell. These results are in contrast to S-bridged dimers [Cu₂(μ-S-Httsc)₂(η¹-Br)₂(Ph₃P)₂] · 2H₂O and [Cu₂(μ-S-Httsc)₂(η¹-Cl)₂(Ph₃P)₂] · 2CH₃CN obtained for R = H and X = Cl, Br (Httsc = thiophene-2-carbaldehyde thiosemicarbazone) as reported earlier. The intermolecular CH_Ph?π interaction in 1-3 (2.797 Å, 1; 3.264 Å, 2; 3.257 Å, 3) have formed linear polymers, whereas the CH_Ph?X and N³?HCH interactions in 4-6 (2.791, 2.69 Å, 5; 2.776, 2.745 Å, 6, respectively) have led to the formation of H-bonded 2D polymer. The PhN¹H?π, interactions (2.547 Å, 8, 2.599 Å, 9) have formed H-bonded dimers only. The Cu?Cu separations are 3.221-3.404 Å (1-6).     

Synthesis of sialyl Lewis<Superscript>a</Superscript> (sLe<Superscript>a</Superscript>, CA19-9) and construction of an immunogenic sLe<Superscript>a</Superscript> vaccine

Sialyl Lewis^a (sLe^a), also termed CA19-9 antigen, is recognized by murine mAb19-9 and is expressed on the cancer cell surface as a glycolipid and as an O-linked glycoprotein. It is highly expressed in a variety of gastrointestinal epithelial malignancies including colon cancer and pancreatic cancer, and in breast cancer and small cell lung cancer, but has a limited expression on normal tissues. sLe^a is known to be the ligand for endothelial cell selectins suggesting a role for sLe^a in cancer metastases and adhesion. For these reasons, sLe^a may be a good target for antibody mediated immunotherapy including monoclonal antibodies and tumor vaccines. However, sLe^a is structurally similar to sLe^x and other blood group related carbohydrates which are widely expressed on polymorphonucleocytes and other circulating cells, raising concern that immunization against sLe^a will induce antibodies reactive with these more widely expressed autoantigens. We have shown previously both in mice and in patients that conjugation of a variety of carbohydrate cancer antigen to keyhole limpet hemocyanin (KLH) and administration of this conjugate mixed with saponin adjuvants QS-21 or GPI-0100 are the most effective methods for induction of antibodies against these cancer antigens. We describe here for the first time the total synthesis of pentenyl glycoside of sLe^a hexasaccharide and its conjugation to KLH to construct a sLe^a-KLH conjugate. Groups of five mice were vaccinated subcutaneously four times over 6 weeks. Sera were tested against sLe^a-HSA by ELISA and against sLe^a positive human cell lines adenocarcinoma SW626 and small cell lung cancer (SCLC) DMS79 by FACS. As expected, mice immunized with unconjugated sLe^a plus GPI-0100 or unconjugated sLe^a mixed with KLH plus GPI-0100 failed to produce antibodies against sLe^a. However, mice immunized with sLe^a-KLH conjugate without GPI-0100 produced low levels of antibodies and mice immunized with sLe^a-KLH plus GPI-0100 produced significantly higher titer IgG and IgM antibodies against sLe^a by ELISA. These antibodies were highly reactive by FACS and mediated potent complement mediated cytotoxicity against sLe^a positive SW626 and DMS79 cells. They showed no detectable cross reactivity against a series of other blood group-related antigens, including Le^y, Le^x, and sLe^x by dot blot immune staining. This vaccine is ready for testing as an active immunotherapy for treating sLe^a positive cancer in clinical settings. Govind Ragupathi and Philip O. Livingston are paid consultants and shareholders in MabVax Therapeutics, Inc., San Diego, CA 92121. The sLe^a vaccine is licensed to MabVax.     

Phenylalanine-Rich Peptides Potently Bind ESAT6, a Virulence Determinant of Mycobacterium tuberculosis,and Concurrently Affect the Pathogen's Growth

Background

The secretory proteins of Mycobacterium tuberculosis (M. tuberculosis) have been known to be involved in the virulence, pathogenesis as well as proliferation of the pathogen. Among this set, many proteins have been hypothesized to play a critical role at the genesis of the onset of infection, the primary site of which is invariably the human lung.

Methodology/Principal Findings

During our efforts to isolate potential binding partners of key secretory proteins of M. tuberculosis from a human lung protein library, we isolated peptides that strongly bound the virulence determinant protein Esat6. All peptides were less than fifty amino acids in length and the binding was confirmed by in vivo as well as in vitro studies. Curiously, we found all three binders to be unusually rich in phenylalanine, with one of the three peptides a short fragment of the human cytochrome c oxidase-3 (Cox-3). The most accessible of the three binders, named Hcl1, was shown also to bind to the Mycobacterium smegmatis (M. smegmatis) Esat6 homologue. Expression of hcl1 in M. tuberculosis H37Rv led to considerable reduction in growth. Microarray analysis showed that Hcl1 affects a host of key cellular pathways in M. tuberculosis. In a macrophage infection model, the sets expressing hcl1 were shown to clear off M. tuberculosis in much greater numbers than those infected macrophages wherein the M. tuberculosis was not expressing the peptide. Transmission electron microscopy studies of hcl1 expressing M. tuberculosis showed prominent expulsion of cellular material into the matrix, hinting at cell wall damage.

Conclusions/Significance

While the debilitating effects of Hcl1 on M. tuberculosis are unrelated and not because of the peptide''s binding to Esat6–as the latter is not an essential protein of M. tuberculosis–nonetheless, further studies with this peptide, as well as a closer inspection of the microarray data may shed important light on the suitability of such small phenylalanine-rich peptides as potential drug-like molecules against this pathogen.     

Cost-effective and concurrent production of industrially valuable xylano-pectinolytic enzymes by a bacterial isolate Bacillus pumilus AJK

Simultaneous production of xylanase and pectinase by Bacillus pumilus AJK under submerged fermentation was investigated in this study. Under optimized conditions, it produced 315?±?16 IU/mL acidic xylanase, 290?±?20 IU/mL alkaline xylanase, and 88?±?9 IU/mL pectinase. The production of xylano-pectinolytic enzymes was the highest after inoculating media (containing 2% each of wheat bran and Citrus limetta peel, 0.5% peptone, 10?mM MgSO₄, pH 7.0) with 2% of 21-hr-old culture and incubated at 37°C for 60?hr at 200?rpm. Xylanase retained 100% activity from pH 6.0 to10.0 after 3?hr of incubation, while pectinase showed 100% stability from pH 6.0 to 9.0 even after 6?hr of incubation. Cost-effective and concurrent production of xylanase and pectinase by a bacterial isolate in the same production media suggests its potential for various biotechnological applications. This is the first report of simultaneous production of industrially important extracellular xylano-pectinolytic enzymes by B. pumilus.