Wolf predation and snow cover as mortality factors in the ungulate community of the Bialowieża National Park,Poland

Summary Wolf-ungulate interactions were studied in the pristine deciduous and mixed forests of the Bialowiea National Park in 1985–1989. The study period included two severe and two mild winters. The community of ungulates inhabiting Bialowiea National Park consisted of red deer Cervus elaphus, 55% of all ungulates; wild boar Sus scrofa, 42%; and roe deer Capreolus capreolus, moose Alces alces, and European bison Bison bonasus, about 1% each. The average size of red deer groups increased from 2.7 (SD 2.35) in spring and summer to 6.9 (SD 6.84) in autumn and winter. In winter the group size of red deer was positively correlated with the depth of snow cover and negatively correlated with the mean daily temperature. Average group size of wild boar did not change significantly between seasons; it was 6.8 (SD 5.16) in spring and summer and 5.7 (SD 4.67) in autumn and winter. Analysis of 144 wolf scats showed that wolves preyed selectively on red deer. In October–April, Cervidae (mostly red deer) constituted 91% of biomass consumed by wolves, while wild boar made up only 8%. In May–September deer formed 77% of prey biomass, and the share of wild boar increased to 22%. In all seasons of the year wolves selected juveniles from deer and boar populations: 61% of red deer and 94% of wild boar of determined age recovered from wolves' scats were young <1 year old. Analysis of 117 carcasses of ungulates found in Bialowiea National Park showed that predation was the predominant mortality factor for red deer (40 killed, 10 dead from causes other than predation) and roe deer (4 killed, none dead). Wild boar suffered most from severe winter conditions (8 killed, 56 dead). The percentage of ungulates that had died from undernutrition and starvation in the total mortality was proportional to the severity of winter.     

In vivo and in vitro dielectric properties of animal tissues at radio frequencies

An open-ended coaxial line and an improved measurement method employing a computer controlled network analyzer were used to measure the permittivity of cat tissues. Muscle, spleen, kidney cortex, liver,and brain cortex were measured in vivo and in vitro at frequencies between 100 MHz and 8 GHz. The differences between the permittivities of these cat tissues, in the aforementioned range of frequencies, when measured in vivo and a few (up to four) hours after death, were found to be within the experimental uncertainty.     

Local secondary structure in ribonuclease A denatured by guanidine · HCl near 1 °C

Recent work has shown that a short α-helix can be stable in water near 1 °C when stabilized by specific interactions between side-chains, while earlier “host-guest” results with random copolymers have shown that a short α-helix is unstable in water at all temperatures in the absence of stabilizing side-chain interactions. As regards the mechanism of protein folding, it is now reasonable on energetic grounds to consider isolated α-helices and β-sheets as the first intermediates on the pathway of protein folding. Proton nuclear magnetic resonance is used here to detect isolated secondary structures in ribonuclease A denatured by guanidine · HCl (GuHCl). Temperatures near 1 °C are used because the low-temperature stability of the C-peptide helix may be a general property of isolated secondary structures in water.Our procedure is to titrate with GuHCl the C2H resonance lines of the four histidine residues of denatured ribonuclease A. Studies of model peptides (C-peptide (lactone) and C-peptide carboxylate, residues 1 to 13 of ribonuclease A; S-peptide, residues 1 to 20) show linear titration curves for the C2H resonance of His12 above 0.5 M-GuHCl, once helix unfolding is complete. Deviations from this line are used to monitor helix formation. The GuHCl titration curves of the other three histidine residues are also linear, once unfolding is complete. The results show that the helix found in C-peptide and S-peptide is also found in denatured ribonuclease A, where it behaves as an isolated helix not stabilized significantly by interactions with other chain segments. Studies of denatured S-protein show that the remaining three His residues, His48, His105 and His119, are involved in structure only below 1 m-GuHCl at 9 °C, pH 1.9. The nature of this structure is not known. The main conclusion from this work is that the His12 helix can be observed as a stable, isolated helix in denatured ribonuclease A near 1 °C, and that none of the other three His residues is involved in a comparably stable local structure. In native ribonuclease A, His12 is within an α-helix and the other three His residues are involved in a 3-stranded β-sheet structure.The helix-coil transition of C-peptide has also been studied for other side-chain resonances by GuHCl titration. Typically, but not always, the titration curves are linear after helix unfolding takes place and resonance lines from different residues of the same amino acid type can be resolved in GuHCl solutions. This is true of the four histidine residues of ribonuclease A although their pK values in 5 m-GuHCl are nearly the same. In C-peptide, the βCH₃ resonance of Ala6 is affected strongly by GuHCl while the lines of Ala4 and Ala5 are shifted only weakly by GuHCl. Evidently the interactions between GuHCl and side-chains in an unfolded peptide depend upon neighboring groups.     

MRE11–RAD50–NBS1 is a critical regulator of FANCD2 stability and function during DNA double‐strand break repair

Monoubiquitination of the Fanconi anaemia protein FANCD2 is a key event leading to repair of interstrand cross‐links. It was reported earlier that FANCD2 co‐localizes with NBS1. However, the functional connection between FANCD2 and MRE11 is poorly understood. In this study, we show that inhibition of MRE11, NBS1 or RAD50 leads to a destabilization of FANCD2. FANCD2 accumulated from mid‐S to G2 phase within sites containing single‐stranded DNA (ssDNA) intermediates, or at sites of DNA damage, such as those created by restriction endonucleases and laser irradiation. Purified FANCD2, a ring‐like particle by electron microscopy, preferentially bound ssDNA over various DNA substrates. Inhibition of MRE11 nuclease activity by Mirin decreased the number of FANCD2 foci formed in vivo. We propose that FANCD2 binds to ssDNA arising from MRE11‐processed DNA double‐strand breaks. Our data establish MRN as a crucial regulator of FANCD2 stability and function in the DNA damage response.     

Resistance of alkylphenol ethoxylate containing six ethoxylene units to biodegradation under the conditions of OECD (Organization for Economic Co-operation and Development) screening test

Biodegradation of a commercially available mixture of octylphenol ethoxylates (Triton X-100) under the condition of OECD 301E screening test was studied by using electrospray ionisation mass spectrometry. It was found that ethoxylate containing six ethoxylene units (OPEO₆) is more resistant to the biodegradation process than other ethoxylates (e.g. than OPEO₅ and OPEO₇). After 40 days of biodegradation process the signal of OPEO₆ was clearly seen, but signals of OPEO₅ and OPEO₇ were not detected. After 40 days, all OPEO_n with n > 4 were converted into carboxylated derivatives. Carboxylated derivatives were observed in negative ion mode as OPEO_n-CH₂COO^? ions. Biodegradation of OPEO₅-CH₂COOH (carboxylated derivative correspondent of OPEO₆) occurred slower than biodegradation of the others, as resulted from obtained ESI mass spectra.     

Statistical evaluation of Ips typographus population density: a useful tool in protected areas and conservation-oriented forestry

Ips typographus (Col., Curculionidae, Scolytinae) occurring on Picea abies stems is a species characterised by large fluctuations in population numbers and causing frequent outbreaks. In protected areas, I. typographus is regarded as a sensitive bioindicator responsive to changes in forest health and vitality. In conservation-oriented forestry, attention is being paid to the ecological value of I. typographus beetles as ecosystem engineers and keystone species, driving forest natural regeneration and conversion. Despite many publications devoted to I. typographus, no accurate method for estimating the population density of this species has been developed. The objective of this study was to develop a statistical method for estimating I. typographus population density that enables calculation of estimation errors. The proposed method consists of two parts: tree-level analyses and stand-level analyses. Part one allows calculation of the total density of I. typographus infestation of each of P. abies selected stem (after selecting sample windfalls), part two allows estimation of the mean total infestation density of the stem in the area investigated. Linear regression functions were applied to part one and survey sampling to part two. The method is only marginally invasive because it involves debarking of one 0.5 m-long stem section on maximum 50 P. abies windfalls (trap trees can optionally be used). The developed method was employed to assess I. typographus population density in the ?wi?tokrzyskie Mountains in Central Poland in an area of ca. 4,000 ha. In 2010, in the area investigated, the mean total I. typographus infestation density of the P. abies stem was 440.6 maternal galleries/m² (from 358.7 to 522.6 maternal galleries/m² with ?? = 0.05; the relative error of estimation was 18.6%). The examined I. typographus population was in a progradation phase. The proposed method can be used in nature reserves, national parks and managed forests, mainly for scientific purposes.     

Apolipoprotein l6, a novel proapoptotic Bcl-2 homology 3-only protein, induces mitochondria-mediated apoptosis in cancer cells

Cancer cells frequently possess defects in the genetic and biochemical pathways of apoptosis. Members of the Bcl-2 family play pivotal roles in regulating apoptosis and possess at least one of four Bcl-2 homology (BH) domains, designated BH1 to BH4. The BH3 domain is the only one conserved in proapoptotic BH3-only proteins and plays an important role in protein-protein interactions in apoptosis by regulating homodimerization and heterodimerization of the Bcl-2 family members. To date, 10 BH3-only proapoptotic proteins have been identified and characterized in the human genome. The completion of the Human Genome Project and the availability of various public databases and sequence analysis algorithms allowed us to use the bioinformatic database-mining approach to identify one novel BH3-only protein, apolipoprotein L6 (ApoL6). The full-length cDNA of ApoL6 was identified, cloned, and functionally expressed in p53-null colorectal cancer cells (DLD-1). We found that overexpression of wild-type ApoL6 induced mitochondria-mediated apoptosis in DLD-1 cells characterized by release of cytochrome c and Smac/DIABLO from mitochondria and activation of caspase-9, whereas ApoL6 BH3 domain deletion allele did not. In addition, overexpression of ApoL6 also induced activation of caspase-8. Furthermore, we showed that adenovirus harboring the full-length cDNA of ApoL6 induced marked apoptosis in a variety of cancer cell types, and ApoL6 recruited and interacted with lipid/fatty acid components during the induction of apoptosis. To our knowledge, this is the first example that intracellular overproduction of an apolipoprotein induces marked apoptosis.