M?ssbauer effect in the `super-reduced' form of the high-potential iron–sulphur protein from Chromatium (Short Communication)

Mössbauer-effect studies of the super-reduced form of Chromatium high-potential iron–sulphur protein indicate that the iron atoms are in a similar valency state to those in reduced ferredoxin from Clostridium pasteurianum, with possibly some inequivalence between the iron atoms within the four-iron centre. Mössbauer spectroscopy also shows magnetic differences between the four-iron centres in the two proteins.     

Evidence for M?ssbauer spectroscopy for different forms of iron core in Pseudomonas aeruginosa bacterial ferritin.

Mössbauer spectroscopic studies of whole cells of Pseudomonas aeruginosa, grown under different conditions, indicate that the predominant form of iron in the cells varies significantly. These differences are interpreted in terms of differences in the nature of the iron cores of the bacterial ferritin, which result from different growth conditions.     

Sharing the water column: physiological mechanisms underlying species-specific habitat use in tunas

Tuna species support some of the world’s largest commercial and recreational fisheries. Their extensive migratory patterns expose them to multiple national and international fisheries and fishery management regimes. Several prized species have become the focus of global conservation efforts and there is a growing worldwide interest in establishing optimal strategies for sustainable tuna fisheries. Although this task has proven to be very challenging, it has taken on a new sense of urgency in the face of the potential effects of global climate change. A better understanding of the interactions between environmental conditions and tuna physiology and how they affect tuna behavior will offer population and stock assessment modelers and fisheries biologists a more mechanistic understanding of tuna distribution patterns and may help predict changes in both geographic and depth-related movement patterns. Indeed, physiological data comprise a growing component of multi-trait analysis approaches to species conservation. Our review aims to summarize what is known about differences among tuna species in distribution patterns, tolerances to environmental conditions, and physiological characteristics that correlate with the capacity to inhabit cooler (deeper, higher latitude) and even hypoxic waters. To achieve this goal, we discuss how these physiological traits are associated with habitat partitioning within the three-dimensional oceanic environment and with niche expansion into cooler and hypoxic waters. We also point out areas where additional research is needed to predict more accurately how future changes in oceanographic conditions will affect the distributions and movement patterns of tunas and their availability to fisheries.     

Distribution of viral abundance in the reef environment of Key Largo, Florida.

The distribution of viral and microbial abundance in the Key Largo, Fla., reef environment was measured. Viral abundance was measured by transmission electron microscope direct counts and plaque titer on specific bacterial hosts in water and sediment samples from Florida Bay (Blackwater Sound) and along a transect from Key Largo to the outer edge of the reef tract in Key Largo Sanctuary. Water column viral direct counts were highest in Blackwater Sound of Florida Bay (1.2 x 10(7) viruses per ml), decreased to the shelf break (1.7 x 10(6) viruses per ml), and were inversely correlated with salinity (r = -0.97). Viral direct counts in sediment samples ranged from 1.35 x 10(8) to 5.3 x 10(8)/cm(3) of sediment and averaged nearly 2 orders of magnitude greater than counts in the water column. Viral direct counts (both sediment and water column measurements) exceeded plaque titers on marine bacterial hosts (Vibrio natriegens and others) by 7 to 8 orders of magnitude. Water column viral abundance did not correlate with bacterial direct counts or chlorophyll a measurements, and sediment viral parameters did not correlate with water column microbial, viral, or salinity data. Coliphage, which are indicators of fecal pollution, were detected in two water column samples and most sediment samples, yet their concentrations were relatively low (<2 to 15/liter for water column samples, and <2 to 108/cm(3) of sediment). Our findings indicate that viruses are abundant in the Key Largo environment, particularly on the Florida Bay side of Key Largo, and that processes governing their distribution in the water column (i.e., salinity and freshwater input) are independent of those governing their distribution in the sediment environment.     

Sequence and expression of the mouse mammary tumour virus env gene

We have determined the DNA sequence of the envelope gene region of the GR strain of mouse mammary tumour virus. The sequence extends for 3012 nucleotides from the single EcoRI site to beyond the PstI site in the 3' long terminal repeat (LTR) of the provirus. There is a major open reading frame from nucleotides 752 to 2818 which encompasses the entire env gene. This reading frame extends through a polypurine tract and into the LTR. There is another open reading frame from the first nucleotide to position 803, presumably corresponding to the end of the pol gene. The splice acceptor site which generates env mRNA has been mapped experimentally to nucleotide 750. The env gene products, gp52 and gp36, have been positioned on the sequence using the directly determined amino acid sequences of the amino terminus of gp52; and both the amino and carboxyl termini of gp36. The start of gp52 is preceded by a series of 19 uncharged amino acids which could function as a typical signal sequence, but this sequence is only part of a much longer leader peptide. The tetrad Arg-Ala-Lys-Arg is the presumed cleavage site in the gPr73env precursor, and occurs just before the gp36 amino terminus. There are five potential asparagine-linked glycosylation sites which agrees with previous experimental results. The gp36 has two long hydrophobic regions at its amino and carboxy termini, these are suggested to act as a fusion peptide and the trans-membrane anchor, respectively.     

Health-related quality of life in ADHD: a pooled analysis of gender differences in five atomoxetine trials

Attention-deficit/hyperactivity disorder (ADHD) is associated with considerable impairment in health-related quality of life (HR-QoL). Atomoxetine has been found to improve HR-QoL in both children and adolescents. However, there is scarcity of data on gender differences in treatment responses to ADHD medications. This pooled analysis of five atomoxetine trials aimed to evaluate treatment differences with respect to HR-QoL and ADHD symptoms across genders. Data from 5 clinical atomoxetine trials (4 from Europe and 1 from Canada) with similar inclusion and exclusion criteria and similar durations (8- to 12-week follow-up) were included in the pooled analysis. All studies included the Child Health and Illness Profile-Child Edition (CHIP-CE) Parent Report Form. In addition, correlations between HR-QoL and ADHD core symptoms were compared between girls and boys. Data from 136 girls and 658 boys (mean age: 9.6 and 9.7 years, respectively) were pooled. Boys and girls were similarly impaired at baseline with minor differences in some of the subdomains. Treatment effect of atomoxetine was significant in both groups for the Risk Avoidance domain and its subdomains. No gender effect with both clinical and statistical significance was found for treatment outcome. Correlations between ADHD Rating Scale and CHIP-CE scores were similar in both genders and were generally low at baseline and moderate at endpoint and for the change from baseline to endpoint. Atomoxetine was effective in improving some aspects of HR-QoL in both genders without any significant differences across genders. Correlations between core symptoms of ADHD and HR-QoL were low to moderate in both boys and girls.     

Growth factors in breast cancer: mitogenesis to transformation.

While endocrine steroid hormones have been known for many years to regulate normal and malignant mammary epithelium, recent studies have led to an appreciation of polypeptide growth factors as locally-acting autocrine and paracrine effectors. In the current article we summarize what is known about growth factor regulation and action in the normal mammary gland and about perturbations of the steroid-growth factor interplay as cancer progresses. A major theme is that oncogenic activation modulates both regulation of production and function of growth factors in the mammary gland.     

Active and passive cation transport and L antigen hertogeneity in low potassium sheep red cells

Several lines of experimental evidence are presented suggesting that the L antigens in low potassium (LK) sheep red cells are associated with separate Na(+)K(+) pump flux is distinct from the action of anti-L(l) on K(+) leak flux, implying that K(+) leak transport sites may not be converted into active pumps by the L antiserum. Treatment of LK red cells with trypsin completely abolished both the stimulation of K(+) pump flux and the enhancement of the rate of ouabain binding brought about by anti- L. That this effect is due to a total destruction of the L(p) determinant associated with the LK pump was evident from the complete failure of anti-L(p) to bind to trypsinized LK red cells. The L(p) antigen can be effectively protected against the trypsin attack by prior incubation with anti-L, indicating that the sites for antibody binding and trypsin action may be closely adjacent at the structural level. Trypsin treatment, however, did not interfere with anti-L(l) reducing ouabain insensitive K(+) leak influx, nor did it prevent binding of anti-L(ly), the hemolytically active L antibody which is probably identical with anti-L(l). The functional independence of the L(p) and L(l) sites was documented by the observation that anti-L(l) still reduced K(+) leak influx in LK cells with experimentally induced high potassium concentrations, at which K(+) pump flux is fully suppressed, whether or not anti-L(p) was binding to the L(p) antigen associated with the LK pump.