Locomotor activity patterns of nineteen fish and five crustacean species from the Baltic Sea

Synopsis Activity patterns of some common Baltic fish species and macrocrustaceans have been investigated in natural light/dark conditions — in most cases for periods of at least one full year. The fauna of the northern Baltic proper consists of species of both marine and freshwater origin, with both types represented in the study. The different patterns found are discussed in relation to light period, light intensity and to the structure and function of the eyes. The following species were considered nocturnal: Idothea baltica, Mesidothea entomon, Gammarus oceanicus, Palaemon adspersus, Anguilla anguilla, Spinachia spinachia, Pholis gunnellus, Zoarces viviparus, Scopthalmus maximus, and Platichtys flesus. These species were considered diurnal: Clupea harengus, Scardinius erythrophthalmus, Gasterosteus aculeatus, Perca fluviatilis, Gobius niger, Taurulus bubalis, and Cyclopterus lumpus. The next three species showed a crepuscular pattern of activity: Praunus flexuosus, Esox lucius and Gymnocephalus cernus. Four species were considered to show inversions of the activity patterns: Pungitius pungitius, Pomatoschistus minutus, Myoxocephalus scorpius and M. quadricornis.     

Transient inhibition of DNA synthesis by 5-fluorodeoxyuridine leads to overexpression of dihydrofolate reductase with increased frequency of methotrexate resistance

Transient but incomplete suppression of DNA synthesis by a single exposure of an asynchronous population of cells to 5-fluoro-2'-deoxyuridine (FdUrd) increases the frequency of appearance of methotrexate (MTX)-resistant colonies. This increase was greater than 10-fold following a 6-h incubation of cells with 3 microM FdUrd prior to selection in MTX, an interval one-half the normal L1210 cell cycle time. During this period of exposure to FdUrd, DNA synthesis decreased to 25% of control rates and cells accumulated at the G1/S interface. The 6-h incubation with FdUrd resulted in greater than a 2.5-fold increase in the dihydrofolate reductase protein level in the treated cell population, which was accounted for, at least in part, by increased de novo synthesis of the enzyme as assessed by [35S]methionine labeling. This increase in dihydrofolate reductase was associated with a decrease in growth inhibition by MTX. A brief reversal (2 h) of FdUrd-induced DNA synthesis inhibition by the addition of thymidine eliminated the amplification of dihydrofolate reductase and the enhanced emergence of MTX-resistant clones. Beyond this, an analysis of clones that survive MTX selection indicates that the dihydrofolate reductase gene copy in cells spontaneously resistant to 50 nM MTX and those which resulted after the additional pretreatment with FdUrd for 6 h are comparable with a 2-4-fold amplification of enzyme in most clones. These studies demonstrate that FdUrd enhancement of dihydrofolate reductase expression can have a profound effect upon the incidence and expression of MTX resistance and that dihydrofolate reductase gene amplification may be another basis for antagonism between these agents.     

Human DNA sequences complementary to the small nuclear RNA U2.

Clones containing sequences complementary to the small nuclear RNA U2 were isolated from a human DNA library (1). Three clones, designated U2/4, U2/6 and U2/7 were purified and characterized by restriction enzyme cleavage, hybridization and heteroduplex analysis. Hybridization showed that the three clones each contained one single region which is complementary to U2 RNA. Restriction enzyme cleavage revealed furthermore that the inserted fragments in the three recombinants are different. Heteroduplex analysis identified a 240-380 bp long duplex region in each heteroduplex which includes sequences complementary to U2 RNA. Heteroduplexes between clones U2/4 and U2/7 as well as between U2/4 and U2/6 revealed two additional approximately 200 bp long homologies. The remainder of the inserts were found to lack measurable sequence homology. Two fragments from clone U2/4 were subcloned in the pBR322 vector and the subclones were used to determine the nucleotide sequence of a region in clone U2/4 which is complementary to U2 RNA. A comparison between the established sequence and the sequence for rat U2 RNA (2) reveals several discrepancies.     

Sequence organization of a viral DNA insertion present in the adenovirus-type-5-transfonned hamster line BHK268-C31

The hamster cell line BHK268-C31 contains two large viral inserts which both include sequences from the left-hand end of adenovirus type 5 (Ad5) DNA. One of these viral inserts has been cloned in the λ vector Charon 4A. Electron microscopic analysis and restriction enzyme mapping shows that the recombinant carries a 4.4-kb-long colinear segment of viral DNA, which is located between map positions 1.5 and 14.2 in the Ad5 genome. The junctions between viral DNA and flanking sequences have been sequenced and found not to show any specific features. One of the junctions is located in the E1 a coding region, 573 bp from the left-hand end of the Ad5 genome, whereas the other junction is situated in the coding region for polypeptide IVa2. The promoter region as well as the cap site for the mRNAs from region E la are thus missing from this insert and its role in viral transformation is unclear.     

Response prediction in chronic hepatitis C by assessment of IP-10 and IL28B-related single nucleotide polymorphisms

Background

High baseline levels of IP-10 predict a slower first phase decline in HCV RNA and a poor outcome following interferon/ribavirin therapy in patients with chronic hepatitis C. Several recent studies report that single nucleotide polymorphisms (SNPs) adjacent to IL28B predict spontaneous resolution of HCV infection and outcome of treatment among HCV genotype 1 infected patients.

Methods and Findings

In the present study, we correlated the occurrence of variants at three such SNPs (rs12979860, rs12980275, and rs8099917) with pretreatment plasma IP-10 and HCV RNA throughout therapy within a phase III treatment trial (HCV-DITTO) involving 253 Caucasian patients. The favorable SNP variants (CC, AA, and TT, respectively) were associated with lower baseline IP-10 (P = 0.02, P = 0.01, P = 0.04) and were less common among HCV genotype 1 infected patients than genotype 2/3 (P<0.0001, P<0.0001, and P = 0.01). Patients carrying favorable SNP genotypes had higher baseline viral load than those carrying unfavorable variants (P = 0.0013, P = 0.029, P = 0.0004 respectively). Among HCV genotype 1 infected carriers of the favorable C, A, or T alleles, IP-10 below 150 pg/mL significantly predicted a more pronounced reduction of HCV RNA from day 0 to 4 (first phase decline), which translated into increased rates of RVR (62%, 53%, and 39%) and SVR (85%, 76%, and 75% respectively) among homozygous carriers with baseline IP-10 below 150 pg/mL. In multivariate analyses of genotype 1-infected patients, baseline IP-10 and C genotype at rs12979860 independently predicted the first phase viral decline and RVR, which in turn independently predicted SVR.

Conclusions

Concomitant assessment of pretreatment IP-10 and IL28B-related SNPs augments the prediction of the first phase decline in HCV RNA, RVR, and final therapeutic outcome.