Effects of Multiple Use on Water Quality of High-Mountain Watersheds: Bacteriological Investigations of Mountain Streams

Bacteriological studies in 1968 and 1969 corroborated earlier findings that a municipal watershed which had been closed to public entry since 1917 yielded water with four to six times the coliform count found in an adjacent mountain watershed open to recreational activities. Similarly, chemical investigations showed higher concentrations of most ions in water from the closed area. Physiological differentiation of coliform and enterococcal bacteria revealed similar types of organisms in both animal droppings and stream water, with fecal coliforms accounting for as much as 70% of the coliform counts observed in the closed area in 1969. Opening of the closed drainage for limited recreation and expanded logging operations in the spring of 1970 coincided with an unexpected decrease in bacterial contamination of that stream. It is postulated that these human activities drove from the watershed a large wild animal population which had contributed substantially to the previous bacterial pollution. It would seem that the practice of closing high-mountain watersheds to public entry is questionable if governmental standards for water quality are to be met, and it also seems that the standards themselves should be reexamined.     

Recovery of steroidal glucosiduronic acids from organic solvents containing anionic liquid ion-exchangers

Solutions of anionic liquid ion-exchangers in organic solvents are potentially useful for extracting steroidal glucosiduronic acids from biological fluids and for purifying mixtures of these acids by chromatography. If a glucosiduronic acid is to be isolated in pure form after either of these procedures, it is necessary to separate it from the ion-exchanger. Separation from an organic solution of tetraheptylammonium chloride may be accomplished by extraction with water under the following conditions, which promote transfer of a glucosiduronate to the aqueous phase: (1) an appropriate solvent (diluent) as the organic phase, (2) the presence in the two-phase mixture of an anion such as myristate or dodecyl sulphate to combine with the tetraheptylammonium ion, and (3) an increase of the pH of the aqueous phase in association with the presence of myristate or dodecyl sulphate. The foregoing factors apply also to removal of glucosiduronates from organic solutions of ion exchangers that are hydrochlorides of tertiary, secondary, or primary amines. Since these amines exert progressively less solubilizing effect for glucosiduronates as the pH of the aqueous phase is increased, the conjugates can be released from the organic phase by adjusting the pH to 10 and omitting the myristate or dodecyl sulphate.     

Alterations in membrane surfaces induced by attachment of carbohydrates

We have examined the behavior of the dry phospholipid dipalmitoylphosphatidylcholine (DPPC) in the presence of several carbohydrate derivatives. These carbohydrate derivatives possess a hydrophobic portion which is incorporated directly into the DPPC membrane and a hydrophilic portion which places the carbohydrate structure at the membrane interface with the surrounding matrix. In the presence of these derivatives, the physical properties of the membrane are altered. These alterations are evident in changes observed in the phosphate and carbonyl vibrational modes of the phospholipid portion of the membrane. In addition, the phase transition behavior of the lipid is significantly altered as evidenced by a reduction in the gel to liquid-crystalline phase transition temperature. These results are consistent with those previously reported for free carbohydrates interacting with membranes in which a water replacement hypothesis has been used to explain the behavior. The attachment of carbohydrates to the membrane enhances these effects by localizing the agent responsible for these alterations at the membrane interface.     

Selection on soil microbiomes reveals reproducible impacts on plant function

Soil microorganisms found in the root zone impact plant growth and development, but the potential to harness these benefits is hampered by the sheer abundance and diversity of the players influencing desirable plant traits. Here, we report a high level of reproducibility of soil microbiomes in altering plant flowering time and soil functions when partnered within and between plant hosts. We used a multi-generation experimental system using Arabidopsis thaliana Col to select for soil microbiomes inducing earlier or later flowering times of their hosts. We then inoculated the selected microbiomes from the tenth generation of plantings into the soils of three additional A. thaliana genotypes (Ler, Be, RLD) and a related crucifer (Brassica rapa). With the exception of Ler, all other plant hosts showed a shift in flowering time corresponding with the inoculation of early- or late-flowering microbiomes. Analysis of the soil microbial community using 16 S rRNA gene sequencing showed distinct microbiota profiles assembling by flowering time treatment. Plant hosts grown with the late-flowering-associated microbiomes showed consequent increases in inflorescence biomass for three A. thaliana genotypes and an increase in total biomass for B. rapa. The increase in biomass was correlated with two- to five-fold enhancement of microbial extracellular enzyme activities associated with nitrogen mineralization in soils. The reproducibility of the flowering phenotype across plant hosts suggests that microbiomes can be selected to modify plant traits and coordinate changes in soil resource pools.     

Inhibition of yeast telomerase action by the telomeric ssDNA-binding protein, Cdc13p

Appropriate control of the chromosome end-replicating enzyme telomerase is crucial for maintaining telomere length and genomic stability. The essential telomeric DNA-binding protein Cdc13p both positively and negatively regulates telomere length in budding yeast. Here we test the effect of purified Cdc13p on telomerase action in vitro. We show that the full-length protein and its DNA-binding domain (DBD) inhibit primer extension by telomerase. This inhibition occurs by competitive blocking of telomerase access to DNA. To further understand the requirements for productive telomerase 3′-end access when Cdc13p or the DBD is bound to a telomerase substrate, we constrained protein binding at various distances from the 3′-end on two sets of increasingly longer oligonucleotides. We find that Cdc13p inhibits the action of telomerase through three distinct biochemical modes, including inhibiting telomerase even when a significant tail is available, representing a novel ‘action at a distance’ inhibitory activity. Thus, while yeast Cdc13p exhibits the same general activity as human POT1, providing an off switch for telomerase when bound near the 3′-end, there are significant mechanistic differences in the ways telomere end-binding proteins inhibit telomerase action.     

Leucine-rich repeat-containing, G protein-coupled receptor 4 null mice exhibit intrauterine growth retardation associated with embryonic and perinatal lethality

Leucine-rich repeat-containing, G protein-coupled receptors (LGRs) belong to the largest mammalian superfamily of proteins with seven-transmembrane domains. LGRs can be divided into three subgroups based on their unique domain arrangement. Although two subgroups have been found to be receptors for glycoprotein hormones and relaxin-related ligands, respectively, the third LGR subgroup, consisting of LGR4-6, are orphan receptors with unknown physiological roles. To elucidate the functions of this subgroup of LGRs, LGR4 null mice were generated using a secretory trap approach to delete the majority of the LGR4 gene after the insertion of a beta-galactosidase reporter gene immediately after exon 1. Tissues expressing LGR4 were analyzed based on histochemical staining of the transgene driven by the endogenous LGR4 promoter. LGR4 was widely expressed in kidney, adrenal gland, stomach, intestine, heart, bone/cartilage, and other tissues. The expression of LGR4 in these tissues was further confirmed by immunohistochemical studies in wild-type animals. Analysis of the viability of 250 newborn animals suggested a skewed inheritance pattern, indicating that only 40% of the expected LGR4 null mice were born. For the LGR4 null mice viable at birth, most of them died within 2 d. Furthermore, the LGR4 null mice showed intrauterine growth retardation as reflected by a 14% decrease in body weight at birth, together with 30% and 40% decreases in kidney and liver weights, respectively. The present findings demonstrate the widespread expression of LGR4, and an essential role of LGR4 for embryonic growth, as well as kidney and liver development. The observed pre- and postnatal lethality of LGR4 null mice illustrates the importance of the LGR4 signaling system for the survival and growth of animals during the perinatal stage.     

An approach to the proteomic analysis of a breast cancer cell line (SKBR-3)

This report describes the profiling of proteins in a sample prepared by laser capture microdissection (LCM) from a breast cancer cell line (SKBR-3). This experimental approach serves as a model system for proteomic studies on selected tissue samples and for studies of specific cell types. The captured cells were isolated in a dehydrated and reduced state and solubilized with a denaturing buffer. After dilution the protein mixture was digested with trypsin and the resulting peptide mixture was fractionated by reversed phase HPLC (RPLC) and analyzed on an ion trap mass spectrometer. A key part of this study is the combination of the LCM process with an extraction/digestion procedure that allowed effective solubilization of a significant part of the cellular sample in a single step. The identity of the peptides was determined by tandem mass spectrometry measurements in which the resulting spectra were compared with genomic and proteomic databases and protein identifications were made. While only peptides with a high probability assignment were used, the interpretation of mass spectral fragmentation patterns were also confirmed by manual interpretation of the spectra. Also, for the more abundant proteins the initial protein assignment from the best match peptide was strengthened by the observation of additional confirmatory peptide identifications. Another selection criteria was correlation of the mass spectrometric studies with clinical and genomic studies of potential cancer markers in tumor samples. This proteomic study allowed identification of the following proteins: human receptor protein kinase HER-2 or ERBB-2 and related kinases HER-3 and HER-4, the gene products from breast cancer type I and II susceptibility genes and cytoskeletal components such as cytokeratins 8, 18 and 19. Other proteins include fibroblast growth factor receptor variants (FGFR-2&4) and T-lymphoma invasion and metastasis inducing protein 1 (TIAM1). In addition several nonreceptor protein kinases YES, FAK and JAK-1 and 3 were identified. Since the study was performed on a limited number of cells (approximately 10,000) it raises the possibility of such studies being performed on individual patient samples prepared by needle biopsy.