The flocculation of bacteria using cationic synthetic flocculants and chitosan

Summary Bacteria are flocculated with high molecular weight cationic synthetic flocculants and chitosan. High charge density polymers are the most effective of the synthetic flocculants. Only chitosan is effective in flocculating the E. coli and B. subtilis cultures in complex broth. The difference in effectiveness between the synthetic flocculants and chitosan for flocculating E. coli, B. subtilis and Z. mobilis may be attributed to hydrogen bonding between the polysaccharide flocculant and cell surface polymers in addition to electrostatic interactions, and, in complex media, complexation of synthetic polymers with anionic polyelectrolytes.     

Potentiation by the lithium ion of morphogenetic responses to a Xenopus inducing factor

We have cultured explants of Xenopus blastular animal cap tissue from embryos that had received an earlier treatment with LiCl and from their untreated siblings, in various concentrations of XTC-cell-derived mesoderm-inducing factor (XTC-MIF, Smith, 1987; Smith et al. 1988). The pretreatment with lithium that we used transforms later morphogenesis in the whole embryo to give radialized body forms with anterior/dorsal levels of structure grossly over-represented. In addition, animal caps from 'Li+' embryos were allowed to develop without exposure to in vitro MIF (Li+ controls) and compared with normal uninduced control explants, and explants were made from normal early blastulae but given various initial treatments with LiCl in culture. The results confirm that the lithium ion itself will not induce mesoderm in competent, animal cap tissue of Xenopus. It does, however, enhance the responsiveness of this tissue to XTC-MIF, in a way that parallels its recently reported effect in the case of another mesoderm inducer of different character, bFGF (Slack et al. 1988). The effects observed are sufficient to imply that the altered body pattern that follows lithium treatment, in whole embryos, could be caused by modulation of the responses to an unaltered pattern of in situ inductive stimuli. We also observe evidence that appreciable inductive signals reach animal pole tissue beyond the limits of mesoderm formation in normal development. Relatively low concentrations of MIF prevent the development of an epidermis-specific marker in dissociated blastular animal cap cells (Symes et al. 1988). When such experiments are repeated in relation to the lithium pretreatment of embryos, such treatment is seen to have sensitized the cell population, so that the MIF concentration range that assures complete suppression of the marker is reduced. The results are discussed in relation to induction considered as pattern formation.     

Observations on the effect of radiotherapy,followed by injection of pig lymph node cells,in reducing the number of pulmonary tumors induced by intravenous injection of tumor cells into isogenic mice

Summary Pulmonary tumors were produced in A. strain mice by intravenous injection of A. strain mammary carcinoma cells. The mesenteric lymph nodes of pigs were immunized by implantation of fragments from the same tumors into the pig mesentery.Tumor-immune pig lymph node cells when injected IV 7 days after tumor cells did not reduce the number of tumors, counted on day 14. However, when preceded by 200 rad thoracic irradiation on day 3 (which increased the number of pig cells settling in the lungs) tumor-immune cells given IV reduced the number of tumors compared with the effect of irradiation alone, or in combination with nonimmune pig cells.When tumor-immune pig cells were injected IP on day 7 (following thoracic irradiation on day 3), no antitumor effect was observed. Thus immediate pig cell/tumor cell contact is important in order to obtain an antitumor effect.Pig cells immunized against a human bladder carcinoma did not reduce pulmonary tumor formation by one of the mouse tumors.     

Nuclear components responsible for the retention of steroid--receptor complexes, especially from the standpoint of the specifcity of hormonal responses.

1. By covalently linking nuclear components from hormone-sensitive cells to Sepharose 2B, it is possible to investigate the interaction between nuclear components and cytoplasmic receptor-steroid complexes by affinity chromatography. 2. Many factors are implicated in the specifity of nuclear-cytoplasmic interactions, including the nature of the nuclear components, the presence of the cytoplasmic receptor protein and the provision of the appropriate steroid ligand. 3. Two distinct sets of binding sites are present in nuclear extracts immobilized to Sepharose 2B, namely a small number of specific high-affinity sites and a larger number of non-specific low affinity-sites. 4. Considerable evidence supports the importance of the high-affinity binding sites in the manifestation of hormonal specificity in different tissues. Although the study has centred largely on androgenresponsive systems, the findings are germane to cytoplasmic-nuclear interactions in general. 5. The high-affinity or acceptor sites in nuclear extracts reside in the basic but non-histone protein fraction. 6. Hormonal specificity is seemingly maintained by both the cytoplasmic and nuclear components, and the results are discussed in the context of the mechanism of action of steroid hormones.     

Studies of polysaccharide fractions from the lipopolysaccharide of Pseudomonas aeruginosa N.C.T.C. 1999.

Two polymeric water-soluble fractions were isolated by gel filtration after mild acid hydrolysis of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 1999. The fraction of higher molecular weight retained the O-antigenic specificity of the lipopolysaccharide and may be 'side-chain' material. This fraction was rich in N (about 10%) and gave several basic amino compounds on acid hydrolysis; fucosamine (at least 2.8% w/w) was the only specifc component identified. The fraction of lower molecular weight was a phosphorylated polysaccharide apparently corresponding to 'core' material. The major components of this fraction and their approximate molar proportions were: glucose (3-4); rhamnose (1); heptose (2); 3-deoxy-2-octulonic acid (1); galactosamine (1); alanine (1-1.5); phosphorus (6-7). In the intact lipopolysaccharide this fraction was probably linked to lipid A via a second residue of 3-deoxy-2-octulonic acid, and probably also contained additional phosphate residues and ethanolamine. The residues of 3-deoxy-2-octulonic acid were apparently substituted in the C-4 or C-5 position, and the phosphorylated heptose residues in the C-3 position. The rhamnose was mainly 2-substituted, though a little 3-substitution was detected. The glucose residues were either unsubstituted or 6-substituted. Four neutral oligosaccharides were produced by partial acid hydrolysis and were characterized by chemical, enzymic, chromatographic and mass-spectrometric methods of analysis. The structures assigned were: Glcpalpha1-6Glc; Glcpbeta1-2Rha; Rhapalpha1-6Glc; Glcpbeta1-2Rhapalpha1-6Glc. The galactosamine was substituted in the C-3 or C-4 position, the attachment of alanine was indicated, and evidence that the amino sugar linked the glucose-rhamnose region to the 'inner core' was obtained.     

Highly Stable Plasmonic Nanostructures on a Nickel-Sputtered Glass and Polymeric Optical Fiber Sensors

Plasmonics - This study shows development of highly sensitive and stable localized surface plasmon resonance (LSPR)-active U-bent glass and polymeric optical fiber (GOF and POF) sensor probes by a...     

Placental tissue metabolome analysis by GC-MS: Oven-drying is a viable sample preparation method

Abstract

Analysis of the human placenta metabolome has great potential to advance the understanding of complicated pregnancies and deleterious fetal outcomes in remote populations, but samples preparation can present unique challenges. Herein, we introduce oven-drying as a simple and widely available method of sample preparation that will facilitate investigations of the placental metabolome from remote and under-studied populations. Placentae from complicated and uncomplicated pregnancies were prepared in three ways (oven-dried at 60?°C, fresh, lyophilized) for metabolome analysis via gas chromatography-mass spectrometry (GC-MS). Multiple computer models (e.g. PLS-DA, ANN) were employed to classify and determine if there was a difference in placentae metabolome and a group of metabolites with high variable importance in projection scores across the three preparations and by complicated vs. control groups. The analyses used herein were shown to be thorough and sensitive. Indeed, significant differences were detected in metabolomes of complicated vs. uncomplicated pregnancies; however, there were no statistical differences in the metabolome of placentae prepared by oven-drying vs. lyophilization vs. fresh placentae. Oven-drying is a viable sample preparation method for placentae intended for use in metabolite analysis via GC-MS. These results open many possibilities for researching metabolome patterns associated with fetal outcomes in remote and resource-poor communities worldwide.     

The birds and the seeds: opportunistic avian nectarivores enhance reproduction in an endemic montane aloe

Opportunistic bird pollination has become more evident in studies that confirm distinct differences in floral adaptations that attract opportunistic, rather than specialist, bird pollinators. Pollination syndrome studies investigating the effectiveness of different pollinator guilds on reproduction seldom do so by measuring seed viability. We studied pollination in Aloe peglerae, a high altitude endemic succulent of the Magaliesberg mountain range, previously thought to be largely sunbird (specialist) pollinated. Using field observation and pollinator exclusion treatments, i.e. (i) open to all visitors, (ii) bird excluded, and (iii) all visitors excluded, we established that birds contributed significantly more to fruit (2.3–5.6 times) and seed (1.3–1.4 times) set than insect or self-pollination, respectively. Overall, pollination by opportunistic avian nectarivores amplified seed production per aloe ~7 and 10 times compared to insects and self-pollination, respectively. One of three opportunistic nectarivores, the Cape Rock-Thrush (Monticola rupestris), played a significant role in pollination, contributing ~60 % of all probes at inflorescences. The difference in reproductive output between insect visited and visitor excluded flowers was not significant and suggests possible self-pollination in A. peglerae which is particularly unusual in Aloe species. Breeding system experiments would help clarify this. In assessing the effectiveness of pollinator guild on seed viability, we found no differences in percentage seed viability, seed germination or seedling emergence between exclusion treatments. Seed viability and germination were low and variable; however, ~19 % seedling emergence was observed across the treatments. Practically, the net effect of bird pollination may result in 8–12 times more potential seedlings compared to insect and self-pollination respectively. These findings highlight the importance of pollination by opportunistic avian nectarivores in Aloe.