The effects of the Kielder scheme on fisheries

The scheme is briefly described. The success of the Kielder and Bakethin reservoir fisheries is examined. The poor condition of trout in Kielder reservoir is considered in relation to physical and chemical factors including water turbidity, low nutrient levels and the location of the reservoirs.
The performance of Kielder hatchery and the difficulties of collecting broodstock of Tyne origin are described.
The effects of water releases from Kielder reservoir upon the salmon, Salmo salar L., and brown trout Salmo trutta L., fisheries within the River North Tyne and examined. Aspects considered include modified water temperature regimes, water chemistry and the magnitude and timing of releases for river regulation and generation of hydroelectric power.
The problems associated with fish passage at Riding Mill weir, the point of water transfer to the River Wear and River Tees, are examined and the progress of inter-river transfers is described.     

Evidence for the association of acyl transferases with the production of nuclear evaginations in maturing eggs of the fern Dryopteris filix-mas.

Utilizing the ability of free CoA to reduce ferricyanide, evidence is presented that acyl transferase activity is associated with the nuclear envelope in the maturing egg of the fern Dryopteris filix-mas. This activity is particularly marked in the nuclear evaginations. This strengthens the view that the evaginations are distinct structures formed by localized growth of the envelope, and not transient extensions of the nucleus.     

Helicobacter pylori and its interaction with chief and parietal cells.

Helicobacter pylori has been shown, along with other Helicobacter species to produce effector molecules that induce substantial physiological changes on acid and pepsin secretion. The effects are clinically evident, and long-term achlorhydria may be a risk factor for gastric cancer. Further identification and characterization of the factors may lead to additional understanding of gastric physiology.     

Karyomegaly in Baryancistrus sp. (Loricaridae) from Amazonian Brazil.

Vesicular karyomegaly of the liver hepatocytes is described from Baryancistrus sp. (Loricaridae), in 3 out of 7 fish, collected from Rio Xingu in central Amazonian (neutral water) Brazil and kept about 2 wk in a holding facility fed with acid water (pH 5.0 to 5.5). Altered cells also occurred in the gill epithelium. The vesicles in the liver were shown to contain a periodic acid-Schiff (PAS)-positive substance or residue.     

Parasitoid–Pathogen–Pest Interactions of Chelonus insularis, Campoletis sonorensis, and a Nucleopolyhedrovirus in Spodoptera frugiperda Larvae

In this study we examined interactions between two solitary endoparasitoids, the braconid Chelonus insularis and the ichneumonid Campoletis sonorensis, and a multiple-enveloped nucleopolyhedrovirus infecting Spodoptera frugiperda larvae. We examined whether ovipositing females minimize interference by discriminating amongst hosts and examined the outcome of within-host competition between parasitoid species and between the parasitoids and the virus. The egg–larval parasitoid Ch. insularis did not discriminate between virus-contaminated and uncontaminated S. frugiperda eggs; all S. frugiperda larvae that emerged from surface-contaminated eggs died of viral infection prior to parasitoid emergence. The larval parasitoid C. sonorensis also failed to discriminate between healthy and virus-infected S. frugiperda larvae or between larvae unparasitized or parasitized by Ch. insularis. Host larvae parasitized in the egg stage by Ch. insularis were suitable for the development of C. sonorensis when they were multiparasitized by C. sonorensis as first, second, third, and fourth instars, whereas emergence of Ch. insularis was dramatically reduced (by 85 to 100%) in multiparasitized hosts. Nonspecific host mortality was significantly higher in multiparasitized hosts than in singly parasitized hosts. The development time and sex ratio of C. sonorensis in multiparasitized host larvae were unaffected by the presence of Ch. insularis larval stages. Both Ch. insularis parasitized and nonparasitized larvae of the same instar (second, third, or fourth instars) had a similar quantitative response to a challenge of virus inoculum. All host larvae that ingested a lethal dose of virus were unsuitable for Ch. insularis development. In contrast, C. sonorensis did not survive in hosts that ingested a lethal virus dose immediately after parasitism, but parasitoid survival was possible with a 2-day delay between parasitism and viral infection and the percentage of parasitoid emergence increased significantly as the interval between parasitism and viral infection increased. The development time of C. sonorensis was significantly reduced in virus-infected hosts compared to conspecifics that developed in healthy hosts. C. sonorensis females that oviposited in virus-infected hosts did not transmit the virus to healthy hosts that were parasitized subsequently. Field applications of virus for biocontrol of S. frugiperda may lead to substantial mortality of immature parasitoids, although field experiments have not yet demonstrated such an effect.     

Chromosome replication and synthesis of non-histone proteins in giant polytene chromosomes

Synthesis of chromosomal proteins was studied by means of autoradiography in giant polytene chromosomes of Chironomus thummi. Incorporation of tryptophane-H₃ into non-histone proteins of the chromosome does not increase during DNA synthesis. Grain count data reveal that chromosomes of cells which are actively replicating DNA do not differ from non-replicating cells in regard to the incorporation of tryptophane-H₃ into chromosomal non-histone protein. Chromosomes of cells which are replicating DNA incorporate about 2 times more lysine-H₃ than do non-DNA replicating cells. Synthesis of histones accounts for this increase in lysinc-H₃ incorporation. This investigation was supported in part by U.S.P.H.S. fellowship number F2CA-23, 971-01A4 from the National Cancer Institute.