Mechanism and base specificity of DNA Breakage in intact cells by neocarzinostatin

When electrophoresed on an agarose gel, the DNA isolated from neocarzinostatin- (NCS-) treated HeLa cells migrates in a ladder of discrete bands indicative of preferential breakage in the linker region of the nucleosomes. The 5'-termini of the drug-induced DNA strand breaks were characterized by reduction of the nucleoside 5'-aldehyde ends to 5'-hydroxyls followed by incorporation of 32P from [gamma-32P]ATP by polynucleotide kinase and treatment of the DNA with hot alkali and alkaline phosphatase prior to the kinase assay to give the total 5'-termini. In DNA isolated from NCS-treated cells, nucleoside aldehyde accounts for 30-45% of the drug-generated 5' ends; the remainder have PO4 termini. By contrast, 5'-terminal nucleoside aldehyde in DNA cut with the drug in vitro exceeds 80% of the total 5' ends. Of the 32P representing nucleoside aldehyde in DNA from NCS-exposed cells, 77% is in TMP; the rest is in AMP much greater than CMP greater than GMP, a distribution in excellent agreement with that obtained for in vitro drug-treated DNA. DNA sequencing experiments, using the 340 base pair alphoid DNA fragment isolated from drug-treated cells, show that the pattern of breakage produced by NCS within a defined sequence of DNA in intact cells is similar to that in the in vitro reaction, with a preferential attack at thymidylate residues, but a much higher concentration of the drug was required to cause comparable breakage in intact cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Photosynthesis and water relations and the role of anatomy in Umbilicariaceae (lichenes) from Central Spain

Summary The response of net photosynthesis and dark respiration in eight species of Umbilicariaceae (lichenes) to temperature (-5, 0, 5, 10, 15, 20, 25, 30°C) and irradiance (55, 110, 220, 400, 620 mol photons m^-2 s^-1 PAR) was studied. The samples were collected in montane and alpine localities of the Spanish Sistema Central. The species differed widely in their net photosynthetic rates. The optimal temperature for net photosynthesis in alpine species was significantly lower than in montane species. Montane species were more photophytic than alpine ones. Water saturation and water loss rate were dependent on morphology and particularly anatomy of the thallus. The physiological and structural data are useful in the interpretation of the ecology and altitudinal distribution of the Umbilicariaceae. No adaptation could be linked to particularities of the mediterranean climate.     

immunocytochemical localization of urokinase-type plasminogen activator in lewis lung carcinoma

The invasively growing and metasizing Lewis lung carcinoma consistently contained urokinase-type plasminogen activator (u-PA) enzyme activity. When investigated immunocytochemically with antibodies against u-PA, different parts of individual tumors showed a pronounced heterogeneity in staining intensity. Strong staining was found in areas with invasive growth and degradation of surrounding normal tissue, while other areas were completely devoid of staining. Immunoreactivity occurred both with a perinuclear cytoplasmic localization in tumor cells and associated with apparently extracellular material. SDS PAGE of tumor extracts, under both reducing and nonreducing conditions, followed by immunoblotting, showed only one immunocytochemically stainable band with an electrophoretic mobility corresponding to that of purified proenzyme to u-PA, while no two-chain u-PA was detected. This indicates that the major part of the activator in Lewis lung carcinoma is present as one-chain pro-u-PA.     

Deoxyribonucleic acid damage by neocarzinostatin chromophore: strand breaks generated by selective oxidation of C-5' of deoxyribose

Among the lesions induced in DNA by neocarzinostatin chromophore are spontaneous and alkali-dependent base release, sugar damage, and single-strand breaks with phosphate (PO4) at their 3' ends and PO4 or nucleoside 5'-aldehyde at the 5' ends. By measuring alkali-dependent thymine release and decomposition of the 5'-terminal thymidine 5'-aldehyde in drug-cut DNA, we show that the kinetics are the same for each process and that the nucleoside aldehyde is the source of about 85% of alkali-dependent thymine release. Reduction of the 5'-aldehyde ends to 5'-hydroxyls followed by incorporation of 32P from [gamma-32P]ATP by polynucleotide kinase permits their selective quantitation. Nucleoside 5'-aldehyde so measured accounts for over 80% of the drug-generated 5' ends; the remainder have PO4 termini. Since these techniques also include the contribution of alkali-labile sites in the measurement of PO4 ends, DNA sequencing was used to measure the ends directly. Using 3'-32P end-labeled DNA restriction fragments as substrates for the drug, it was found that drug attack at a T results in mainly two bands--the stronger one represents oligonucleotide with 5'-terminal nucleoside 5'-aldehyde and may account for over 90% of a particular break. Its structure was verified by its isolation from the sequencing gel, followed by various chemical and enzymatic treatments. In each case, the mobility of the product on the gel was altered in a predictable manner. In addition to spontaneous breaks, neocarzinostatin also causes alkali-labile breaks preferentially at T residues. These sites are heterogeneous in their sensitivity to alkali and are protected by reduction.     

Leaf area index determination in an alder forest: a comparison of three methods

Leaf area index (LAI) of a stand of adult black alder trees(Alnus glutinosa L., Gaertn.) was determined by means of threeindependent methods. (1) The seasonal course of LAI was directlyobtained by counting leaves in situ and adding up their areas,estimated from harvested subsamples of leaves. (2) The seasonalvariation of LAI in the stand was estimated using the Li-CorLAI-2000 PCA in parallel and with this instrument a VegetationArea Index (VAI, projected area of all phyto-elements) was actuallymeasured. (3) Maximum LAI was calculated from leaf litter collectionstaking into account specific leaf area within different layersof the alder crown. Direct LAI estimates (1) and calculationsfrom leaf litter (3) revealed the same figure of maximum LAI(4.8). This LAI was reached in August. The LAI-2000 PCA capturedthe seasonal variation and underestimated, by 11% on average,the LAI obtained directly. Compared with results gained withother broad-leaved tree species the LAI-2000 PCA values foralder were reliable. It is suggested that this is due to thehorizontal homogeneous structure of the main leaf layer. Thisis in the periphery of the crown, where 90% of the light interceptionoccurs. Taking the het-erogeneity into account a satisfactorycompatibility of the three methods applied to the alder standwas achieved. Key words: Alnus glutinosa, leaf area index, in situ counting, LAI-2000 PCA, litter collections     

Productivity and temperature biology of two snowbed bryophytes

Summary Chlorophyll distribution within the carpets, CO₂ gas exchange under controlled conditions, and heat resistance of the snowbed bryophyte Anthelia juratzkana (Limpr.) Trev. were investigated. Also the gas-exchange parameters of the co-occurring Polytrichum sexangulare Floercke were assessed. Only the uppermost 4 mm layer of Anthelia carpets contains sufficient pigments for photosynthesis. At light saturation and optimal temperatures (6–11°C) the maximum rates of CO₂ uptake are 0.7 mg CO₂ g^-1dw h^-1 in Anthelia and 1.5 mg CO₂ g^-1dw h^-1 in Polytrichum. Gas exchange reaches light saturation at about 300 E m^-2s^-1 in both species. At +2°C the light compensation point is reached at ca. 10E m^-2s^-1 and increases significantly with increasing temperature. The lower temperature compensation point is reached at-4°C in Anthelia and does not drop much below-5°C in Polytrichum. Anthelia cannot sustain net photosynthesis beyond 30°C and Polytrichum not beyond 32°C. Nine month storage under dark, cold and wet conditions does not affect the photosynthetic capability of Anthelia. As a response, however, the net photosynthesis rate is depressed due to an increase of the respiration rates. Polytrichum sexangulare did not tolerate the storage so well. The heat resistance limit of Anthelia is low (39°C). There is evidence that the distribution of the two bryophytes within snowbed communities is determined by their capability to make use of low light intensities and their low temperature demand for optimal photosynthetic rates. Being resistant to long lasting cold, wet, and dark conditions, Anthelia is particularly adapted to grow in the border zone along permanent snowpatches. Polytrichum is more productive and is therefore capable of competing successfully at sites which are less extreme and therefore accessible for higher plants.     

Post-construction avian mortality monitoring at Project West Wind

Abstract

Post-construction avifauna investigations were undertaken at Project West Wind, Meridian Energy Limited's 62-turbine wind farm on the Wellington south coast. These investigations were required in accordance with the resource consent conditions to quantify the level of avian mortalities occurring at the wind farm, particularly in regard to New Zealand falcon (Falco novaeseelandiae), kākā (Nestor meridionalis) and kererū (Hemiphaga novaeseelandiae). This is the first comprehensive study at a New Zealand operating wind farm. The methods included three field components necessary to calculate annual estimates of mortalities across the wind farm site: routine turbine searches; carcass detection trials; and carcass removal trials. Results from years 1 and 2 of a three-year programme are presented. To date, mortalities have been recorded for 17 taxa at 18 of the 24 study turbines. There have been no recorded mortalities of falcon, kākā or kererū. Australasian harrier (Circus approximans) has been the species for which the most mortalities have been recorded. Overall estimated annual mortality rates for years 1 and 2 were calculated to be approximately six and five birds per turbine respectively.     

Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon

The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non-additive genetic and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non-additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss whether the similarities in architectures of these populations is the result of natural selection across a common juvenile environment.