Singing streams: Describing freshwater soundscapes with the help of acoustic indices

1. Understanding soundscapes, that is, the totality of sounds within a location, helps to assess nature in a more holistic way, providing a novel approach to investigating ecosystems. To date, very few studies have investigated freshwater soundscapes in their entirety and none across a broad spatial scale.
2. In this study, we recorded 12 freshwater streams in South East Queensland continuously for three days and calculated three acoustic indices for each minute in each stream. We then used principal component analysis of summary statistics for all three acoustic indices to investigate acoustic properties of each stream and spatial variation in their soundscapes.
3. All streams had a unique soundscape with most exhibiting diurnal variation in acoustic patterns. Across these sites, we identified five distinct groups with similar acoustic characteristics. We found that we could use summary statistics of AIs to describe daytimes across streams as well. Most difference in stream soundscapes was observed during the daytime with significant variation in soundscapes both between hours and among sites.
4. Synthesis and Application. We demonstrate how to characterize stream soundscapes by using simple summary statistics of complex acoustic indices. This technique allows simple and rapid investigation of streams with similar acoustic properties and the capacity to characterize them in a holistic and universal way. While we developed this technique for freshwater streams, it is also applicable to terrestrial and marine soundscapes.

     

The human lymphocyte in vitro cytogenetic assay: positive and negative control observations on approximately 30000 cells

Data are presented from the cytogenetic analysis of the peripheral lymphocytes from 94 male and 15 female donors. However, a much smaller number of regular donors were selected for regular use. A total of 28674 cells were analysed and these acted as negative and positive controls in the in vitro human lymphocyte tests accumulated in this laboratory over a 6-year period. The significant observations were:. (1) in untreated and solvent control treated cultures (a) no chromosomal interchanges were observed in 21570 cells; (b) the incidence of dicentrics was less than 1 per 10000 cells; (c) other types of aberrations were seen with an increased frequency, chromosomal gaps being the most variable. (2) The reference clastogens mitomycin C and cyclophosphamide produced high and remarkably consistent yields of all types of aberrations. It is concluded that when screening compounds in vitro for new genotoxins, aberrations such as chromosomal interchanges and dicentrics (due to their rarity in negative control cultures) should be accorded greater significance than the several other types of aberrations routinely seen. These conclusions emphasize the value of maintaining and updating adequate historical control records.     

Properties of purified folate-binding proteins from chronic myelogenous leukemia cells

Folate-binding protein(s) from chronic myelogenous leukemia cells have been purified using acid dialysis, ammonium sulfate fractionation and affinity chromatography. The purified preparation which migrates as a single band on disc electrophoresis could be separated by DEAE agarose chromatography into two folate-binding proteins (binders I and II) which bind molar equivalents of folic acid. One binder (I) eluted from DEAE at 1 mM sodium phosphate, pH 6.0, and the other (II) at 100 mM sodium phosphate, pH 7.4. Analysis of the purified mixture, which contained more than 90% binder II, by sedimentation equilibrium centrifugation indicated a homogeneous protein with a calculated molecular weight of 44000. Antiserum raised against the purified mixture gave a single precipitin line by immunodiffusion against a preparation of partially purified cell lysate.Hydrolysis of the more acidic binder (II) with neuraminidase converted it to a weakly acidic protein similar to binder I suggesting that these binders are glycoproteins which differ in sialic acid content. With isoelectric focusing, the binding of folic acid would be demonstrated at pH 6.7, 7.3, 7.8 and 8.2 for binder I, and at pH 5.1, 5.8 and 6.5 for binder II. Binders I and II had equally high affinity for folic acid and dihydroflate, lower affinity of N⁵-methyl-tetrahydrofolate, and no apparent affinity for N⁵-formytetrahydrofolate or methotrexate.     

Live haploid-diploid and other unusual mosaic chickens (Gallus domesticus)

Sixteen haploid-diploid chickens, four diploid-triploids, and one haploid-diploid-triploid chicken have been found in a layer line of crossbred origin. Live haploid-euploid vertebrates have not been reported previously. Flow cytometric analysis revealed 1-80% haploid red blood cells (RBCs) in the haploid-euploid chickens and 5-30% triploid RBCs in the diploid-triploids. Mosaic cell lines were also found in leukocytes and many tissues. The haploid-diploid chickens were all phenotypically normal and fertile, but the phenotype and fertility of the diploid-triploid chickens depended on their sex-chromosome complements and the ratio of diploid to triploid cells. The haploid cell lines are thought to originate from supernumerary spermatozoa, and the diploid-triploids from binucleated oocytes with meiotic errors. It is likely that genetic factors are partly responsible for the occurrence of these mosaic chickens.     

Zygotic induction of the rac locus can cause cell death in E. coli

Summary Conjugational transfer of the rac locus of E. coli K-12 into a Rac^– recipient strain (i.e. rac ⁺xrac^–) results in the killing of a majority of the recipient cells. The efficiency of killing depends somewhat on the plating medium, and can be as high as 98%. The killing is not observed in the rac ⁺xrac⁺, rac ^–xrac^– or rac ^–xrac⁺ configurations. The rac locus, which has the properties of a cryptic prophage, may carry a function analogous to the kil function of bacteriophage lambda, or may instead cause killing by some replication related process.