Detection and eradication of a non-native Collembola incursion in a hydroponics facility in East Antarctica

A non-native incursion of the collembolan, Xenylla sp. was found within the hydroponics facility at Davis Station, East Antarctica in May 2014. A rapid response was implemented to eradicate the incursion, including localised insecticide use, incineration of plants and growing media, sterilisation of the facility and three cycles of freezing/thawing of both internal rooms and external sub floor areas. Two consecutive years of summer monitoring programs have not detected any Collembola in station buildings or in the surrounding environment, suggesting the eradication was successful. This case highlights the importance of a multiple barrier approach to non-native species risks, and how activation of the last barrier—regular surveillance—resulted in early detection. The use of an online, real-time incident reporting system facilitated efficient communication between scientific experts, operational managers and expeditioners on site, resulting in a rapid and effective response following detection and potentially the first successful eradication of a non-native microarthropod in Antarctica. Monitoring will continue to confirm eradication.     

Differential cytotoxic T-lymphocyte responsiveness to the hepatitis B and C viruses in chronically infected patients.

Cytotoxic T lymphocytes (CTL) are thought to control hepatitis B virus (HBV) infection, since they are readily detectable in patients who clear the virus whereas they are hard to detect during chronic HBV infection. In chronic hepatitis C virus (HCV) infection, however, the virus persists in the face of a CTL response. Indeed, most infected patients respond to one or more HCV-1 (genotype 1a)-derived CTL epitopes in the core, NS3, and NS4 proteins, and the CTL response is equally strong in patients infected by different HCV genotypes, suggesting broad cross-reactivity. To examine the effect of the HCV-specific CTL response in patients with chronic hepatitis C on viral load and disease activity, we quantitated the strength of the multispecific CTL response against 10 independent epitopes within the HCV polyprotein. We could not detect a linear correlation between the CTL response and viral load or disease activity in these patients. However, the CTL response was stronger in the subgroup of patients whose HCV RNA was below the detection threshold of the HCV branched- chain DNA assay than in branched-chain-DNA-positive patients. These results suggest that the HCV-specific CTL response may be able to control viral load to some extent in chronically infected patients, and they indicate that prospective studies in acutely infected patients who successfully clear HCV should be performed to more precisely define the relationship between CTL responsiveness, viral clearance, and disease severity in this infection.     

Evolution of eutherian cytochrome c oxidase subunit II: heterogeneous rates of protein evolution and altered interaction with cytochrome c

Cytochrome c oxidase subunit II (COII), encoded by the mitochondrial genome, exhibits one of the most heterogeneous rates of amino acid replacement among placental mammals. Moreover, it has been demonstrated that cytochrome c oxidase has undergone a structural change in higher primates which has altered its physical interaction with cytochrome c. We collected a large data set of COII sequences from several orders of mammals with emphasis on primates, rodents, and artiodactyls. Using phylogenetic hypotheses based on data independent of the COII gene, we demonstrated that an increased number of amino acid replacements are concentrated among higher primates. Incorporating approximate divergence dates derived from the fossil record, we find that most of the change occurred independently along the New World monkey lineage and in a rapid burst before apes and Old World monkeys diverged. There is some evidence that Old World monkeys have undergone a faster rate of nonsynonymous substitution than have apes. Rates of substitution at four-fold degenerate sites in primates are relatively homogeneous, indicating that the rate heterogeneity is restricted to nondegenerate sites. Excluding the rate acceleration mentioned above, primates, rodents, and artiodactyls have remarkably similar nonsynonymous replacement rates. A different pattern is observed for transversions at four-fold degenerate sites, for which rodents exhibit a higher rate of replacement than do primates and artiodactyls. Finally, we hypothesize specific amino acid replacements which may account for much of the structural difference in cytochrome c oxidase between higher primates and other mammals.      

Iridoids from Desfostainia Spinosa

The leaves of Desfontainia spinosa were found to contain the known iridoid glucosides loganin and loganic acid. Loganetin, the aglucone of loganin was also isolated. This compound has not previously been reported as occurring naturally.     

Ontogeny of the insulin response to glucose in fetal and adult sheep

The purpose of the present experiments was to examine in sheep whether the fetal insulin response to glucose was present by day 110 (d110) of pregnancy and whether the magnitude of the fetal insulin response changed between d110 and d145 (term). We also compared the responses observed in fetuses to those of adult nonpregnant sheep. Basal concentrations of glucose measured in plasma collected from the fetal femoral artery rose progressively between d110 and d145 of gestation, but did not attain the plasma glucose concentrations measured in adult sheep. Peak glucose concentrations in fetuses were achieved 10 min following the bolus injection of glucose (0.8 g/kg estimated fetal body weight) into the fetal femoral vein, and peak values increased with gestational age. Significantly higher peak glucose concentrations were achieved in adult sheep. The concentration of insulin rose rapidly in fetuses at d110, and a similar time course of insulin release in plasma was seen at all gestational ages. The peak plasma insulin concentrations were achieved at 20 min and were significantly greater in older (d140-145) than younger (d125-130) fetuses (p less than 0.05). Peak insulin values in fetuses were much less than in adult sheep. In adult sheep glucose and insulin concentrations remained elevated at 120 min following the injection of glucose, whereas in the fetus the concentration of insulin had returned to preinjection values by 60 min. The insulin/glucose ratio did not change in fetal lambs over the last one third of gestation and was not different from the adult sheep.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postoperative radiotherapy and late mortality: evidence from the Cancer Research Campaign trial for early breast cancer.

OBJECTIVE--To identify any excess mortality caused by adjuvant radiotherapy for early breast cancer. DESIGN--Prospective randomised clinical trial. Two thousand subjects needed for study to have a 90% chance of detecting a difference in survival rate of 7% with 95% significance. Patients were followed up until June 1988, giving follow up of 158-216 months. SETTING--A multicentre trial mainly drawing patients from centres in the United Kingdom. PATIENTS--2800 Women presenting with clinical stage I or II carcinoma of the breast from June 1970 to April 1975. INTERVENTIONS--One group of women (n = 1376) had simple mastectomy followed by immediate postoperative radiotherapy (1320 to 1510 rets). The remaining women (n = 1424) had simple mastectomy with subsequent careful observation of the axilla, radiotherapy being delayed until there was obvious progression or recurrence of disease locally. END POINT--Increased mortality in patients treated with radiotherapy from causes other than breast cancer. MEASUREMENTS AND MAIN RESULTS--Survival was measured from time of first treatment to death or last follow up. Deaths from any cause and from specified causes were counted as events. Comparison over the whole follow up showed a slight excess mortality in the group treated with radiotherapy (relative risk 1.04; 95% confidence interval 0.94 to 1.15). The relative risk of death from breast cancer was 0.97 (0.87 to 1.08) but that of death from other causes was 1.37 (1.09 to 1.72), the increase mainly being in women who had had tumours of the left breast (1.61 (1.17 to 2.24)) and had been treated with orthovoltage (1.85 (1.27 to 2.71)). Analysis of causes of death after five years showed a relative risk of 2.11 (1.25 to 3.59) for new malignancies and of 1.65 (1.05 to 2.58) for cardiac disease, the increase in cardiac mortality being most pronounced in patients who had had tumours of the left breast and whose treatment had included orthovoltage radiation (relative risk 2.67 (1.28 to 5.55)). CONCLUSIONS--Adjuvant radiotherapy after simple mastectomy for early breast cancer produces a small excess late mortality from other cancers and cardiac disease. The risk has to be balanced against the higher risk of local recurrence when immediate postoperative radiotherapy is not given. The balance has to be assessed for each patient, and for many patients radiotherapy will still be desirable in the initial treatment of their early breast cancer.     

The DNA sequence of argI from Escherichia coli K12.

The argI gene from E. coli K12 has been sequenced. It contains an open reading frame of 1002 bases which encodes a polypeptide of 334 amino acids. Three such polypeptides are required to form the functional catalytic trimer (c3) of ornithine transcarbamoylase (OTCase-1, EC 2.1.3.3). The molecular mass of the mature trimer deduced from the amino acid sequence is 114,465 daltons. An altered form of argI was produced when a 1.6 kilobase DdeI fragment was subcloned into the HincII site of plasmid pUC8 extending the open reading frame an additional 20 nucleotides. It has been previously reported that the amino-terminal region of the respective polypeptides of argI, argF, and pyrB of E. coli possessed significant homology. In contrast, the homologous promoter/operator regions of argI and argF did not appear to share any homologies with pyrB. However, a closer scrutiny of the nucleotide sequence immediately preceding the pyrBI attenuator revealed a remarkable similarity to the argI and argF control region.     

Effects of EDTA treatment upon the protein subunit composition and mechanical properties of mammalian single skeletal muscle fibers

Considerable interest has been focused on the role of myosin light chain LC(2) in the contraction of vertebrate striated muscle. A study was undertaken to further our investigations (Moss, R.L., G.G. Giulian, and M.L. Greaser, 1981, J. Biol. Chem., 257:8588-8591) of the effects of LC(2) removal upon contraction in skinned fibers from rabbit psoas muscles. Isometric tension and maximum velocity of shortening, V(max), were measured in fiber segments prior to LC(2) removal. The segments were then bathed at 30 degrees C for up to 240 min in a buffer solution containing 20 mM EDTA in order to extract up to 60 percent of the LC(2). Troponin C (TnC) was also partially removed by this procedure. Mechanical measurements were done following the EDTA extraction and the readditions of first TnC and then LC(2) to the segments. The protein subunit compositions of the same fiber segments were determined following each of these procedures by SDS PAGE of small pieces of the fiber. V(max) was found to decrease as the LC(2) content of the fiber segments was reduced by increasing the duration of extraction. EDTA treatment also resulted in substantial reductions in tension due mainly to the loss of TnC, though smaller reductions due to the extraction of LC(2) were also observed. Reversal of the order of recombination of LC(2) and TnC indicated that the reduction in V(max) following EDTA treatment was a specific effect of LC(2) removal. These results strongly suggest that LC(2) may have roles in determining the kinetics and extent of interaction between myosin and actin.