Accumulation of cesium and radiocesium in forest litter in selected regions of poland and its influence on litter-to-mushroom transfer factor

The aim of this work was to check whether the stable cesium content in forest litter affects the value of radiocesium from litter-to-mushroom transfer factorTf or not. Total cesium in litter, measured by AAS, varied from 0.1–2.7 μg/g. These data, combined with earlier results for mushrooms, showed no simple correlation forTf. More complex relationships provided very high correlation coefficients, but their validity needs further investigation.     

The role of shaded cocoa plantations in the maintenance of epiphytic orchids and their interactions with phorophytes

生境丧失和破碎化是热带森林生物多样性的主要威胁。遮荫的可可种植园(SCP)等农业生态系统为热带森林生物群提供了庇护。然而,在这些转化后的生境中是否还维持种间生态的相互作用,目前尚鲜为人知。我们评定附生兰花群落的多样性、繁殖状态和光合代谢(CAM或C₃),以及与热带雨林(TRF)相比,它们与SCP中寄主树种(附生植物)之间的相互作用。在墨西哥东南部,对TRF和SCP中各三个采样地点进行研究。每个采样地点建立了4个400平方米的样地,调查记录所有兰花及其附生植物。我们依据花/果实(或残体)是否存在来确定每个兰花个体的繁殖(成体)或非繁殖(幼体)状态,并根据文献确定每种兰花的光合作用途径。我们采用真正的分集和生态网络的方法分别分析兰花的多样性以及兰科与附生植物间的相互作用。我们一共记录了47个兰花种的607个个体。在TRF (19个有效物种)中的兰花多样性高于SCP (11个有效物种),两个生境之间仅共享7个物种。SCP (53%)中的CAM兰花物种比TRF (14%)更常见。在群落水平上,SCP维持了非生殖兰花和生殖兰花的比例以及TRF兰科附生植物网络的嵌套结构和特异化水平。然而,SCP中仅保留一部分的TRF附生兰花,突显出保护TRF的重要性。尽管存在这种差异,诸如SCP类型的遮荫农业生态系统仍然可以维持天然林的一些多样性和功能,因为SCP附生兰花群落主要由CAM物种组成,其附生植物构成了一个嵌套的相互作用网络,对干扰形成了更强的抗性。     

Accounting for mating pair formation in plasmid population dynamics

Plasmids are important vehicles for horizontal gene transfer and rapid adaptation in bacteria, including the spread of antibiotic resistance genes. Conjugative transfer of a plasmid from a plasmid-bearing to a plasmid-free bacterial cell requires contact and attachment of the cells followed by plasmid DNA transfer prior to detachment. We introduce a system of differential equations for plasmid transfer in well-mixed populations that accounts for attachment, DNA transfer, and detachment dynamics. These equations offer advantages over classical mass-action models that combine these three processes into a single “bulk” conjugation rate. By decomposing the process of plasmid transfer into its constituent parts, this new model provides a framework that facilitates meaningful comparisons of plasmid transfer rates in surface and liquid environments. The model also allows one to account for experimental and environmental effects such as mixing intensity. To test the adequacy of the model and further explore the effects of mixing on plasmid transfer, we performed batch culture experiments using three different plasmids and a range of different mixing intensities. The results show that plasmid transfer is optimized at low to moderate shaking speeds and that vigorous shaking negatively affects plasmid transfer. Using reasonable assumptions on attachment and detachment rates, the mathematical model predicts the same behavior.     

Evaluation of zinc content in children’s hair

The zinc content in the hair of 654 children living in various rural and industrial areas in southern Poland was assayed by means of the atomic absorption spectrometry, following the dry digestion procedure. The hair of girls exhibited statistically significant higher level of Zn than the boys’ hair, although in the site of extremal Zn contamination, the inverse relation was found.     

Antioxidant and Proteinase Inhibitory Activities of Selected Poppy (Papaver somniferum L.) Genotypes

Poppy seeds (Papaver somniferum L.) belong to tasty food ingredients however, they should be considered also as valuable source of biologically active compounds. Content of selected metabolites, antioxidant and proteinase inhibitory activities were analyzed in vitro in extracts from seeds of fifteen poppy genotypes. Considerable variation in all parameters was detected within the set of analyzed poppy genotypes. The genotype Major expressed the highest antioxidant activity determined by all four methodological approaches (DPPH, ABTS, FRAP, RP). The genotype MS 423 exhibited the highest inhibitory activities against trypsin, thrombin and collagenase. Very specific position among all had the genotype Redy . Its grain extract reached significantly high levels in 9 out of 14 measured parameters (TPC, TFC, TTC, TAC, FRAP, RP, inhibitory activities against trypsin, thrombin, collagenase). Edible grains of poppy are valuable source of natural compounds which may be beneficial in pathological states associated with oxidative stress or increased proteinase activities.     

Production of stress-inducible form of heat-shock protein 70 in mouse peritoneal adherent cells afterin Vivo infection byFrancisella tularensis

Heat-shock proteins (hsp) are ubiquitously produced molecules which participate in the protection of cells from environmental perturbation. Moreover, the members of the heat-shock protein 60 (hsp60) and 70 (hsp70) families play an important role in pathogen-host interactions. We studiedin vivo production of the 70-kDa heat-shock proteins in the extract of peritoneal exudate cells (PEC) from mice injected intraperitoneally with an attenuated vaccine strain (LVS) ofFrancisella tularensis. We found a differential production of a highly stress-inducible member of the hsp70 family, designated hsp72, in three inbred strains of mice exhibiting either resistance or susceptibility toF. tularensis LVS infection. Whereas in tularemia-resistant mice hsp72 was even expressed in PEC without injection of bacteria and its production further increased on day 3 and slowly declined on days 5 and 7 after injection, in susceptible mice hsp72 production was highly inducble and restricted only to day 3 afterin vivo infection. Further analysis of hsp72 expression revealed intracellular hsp72 accumulation and its preferential production by peritoneal adherent cells.     

Co-inoculation ofBorrelia afzelii with tick salivary gland extract influences distribution of immunocompetent cells in the skin and lymph nodes of mice

The impact of Ixodes ricinus salivary gland extract (SGE) on inflammatory changes in the skin and draining lymph nodes of mice, elicited by the infection with the important human pathogen, B. afzelii, was determined using flow cytometry. SGE injected together with spirochetes reduced the numbers of leukocytes and gammadelta-T lymphocytes in infected epidermis at early time-points post infection. In draining lymph nodes, the anti-inflammatory effect of SGE was manifested by the decrease of total cell count compared with that in mice treated with inactivated SGE. Changes in subpopulations of immunocompetent cells apparently reflected the effect of SGE on the proliferation of spirochetes in the host. The significance of tick saliva anti-inflammatory effect for saliva activated transmission of B. afzelii is shown.     

Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure

During isometric contractions, slow twitch soleus muscles (SOL) from rats with chronic heart failure (chf) are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic) contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf) if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off) at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max)) and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max) and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.     

Influence of Fructose and Fatty-Rich Diet Combined with Vanadium on Bone Marrow Cells

The aim of the study is to investigate the influence of diet treatment on bone marrow cells. Normal male Wistar rats were divided into six groups (n?=?6 per group): control with normal diet (C), increased fructose (31 % w/w in fodder) (Fr) and high fatty (30 % w/w of animal fat in fodder) diet (Fa), and the same diets with vanadium complex ([VO(4,4′ Me₂-2,2′ Bpy)₂]SO₄)?·?H₂O (CV, FrV and FaV). During 5 weeks, the animals had unlimited access to food and water. Immediately after anaesthetizing and sacrificing the animals, bone marrow smears were prepared from the femurs. Different types of cell lines in the animal smears were examined under the microscope: erythroid line, myeloid line, monocytic line, megakariocytic line and lymphoid line. Addition of fructose or animal fat had evident influence on the proportional composition of the bone marrow cells. In erythroid precursors, addition of both investigated products resulted in a statistically significant increase of percentage of this type of cells. A reverse effect was observed for the lymphoid cell line where addition of both tested diets decreased quantity of these cells in comparison to the control diet. In the same lines, addition of vanadium intensified the observed changes. In the case of other types of cell lines, statistically significant changes were not observed.     

Influence of Vanadium–organic Ligands Treatment on Selected Metal Levels in Kidneys of STZ Rats

The objective of the study was to investigate the effects of five organic vanadium complexes supplement and a small dose of insulin injection on V, Fe, Cu, Zn, Mn, Ca, and K level in the streptozotocin diabetic rat’s kidney during a 5-week treatment with the tested complexes. In all groups of animals, metal level in the lyophilized kidney organs was investigated by means of the proton induced X-ray emission method. Tissue vanadium level was naturally higher in vanadium-treated rats. The maximum level of vanadium was observed in the kidney ( $ {x_{\text mean}} =16.6\ \upmu \mathrm{g}/\left. \mathrm{g} \right) $ . The influence of vanadium administration on other metal level in rat’s tissue was also investigated. Spectacular influence of vanadium action was observed on copper and zinc level in examined tissue.