Comparative analyses of <Emphasis Type=Italic>Astacus leptodactylus</Emphasis> morphological characteristics from Croatia and Armenia

Narrow-clawed crayfish, Astacus leptodactylus is a native European freshwater crayfish species, also distributed in Croatian freshwater systems belonging to the Black Sea drainage. Its taxonomical status is still in the process of change and discussion, and the data on morphological, molecular, ecological and zoogeographical characteristics of this species are scarce. Therefore, comparative analyses of morphological characteristics were applied with the aim to contribute to the knowledge on the morphometrical and meristical characteristics of A. leptodactylus. Recent research proved that measurements of a large number of morphometrical characteristics, in combination with multivariate statistical analysis, could provide a good instrument for identification and differentiation between populations. In this research altogether 143 animals were analysed (121 from two Croatian populations and 22 from Armenia). 22 morphometrical characteristics and 4 meristical characteristics, per crayfish, were measured. It was found that males and females differ between populations in measured meristical and morphometrical characteristics. None of recorded meristical characteristics proved itself to be reliable characteristic for distinguishing populations. From measured morphometrical characteristics the most discriminant characteristics for separating males from different populations were those describing carapace shape and for females those that describe shape of the claws.     

Autophagy protein Rubicon mediates phagocytic NADPH oxidase activation in response to microbial infection or TLR stimulation

Phagocytosis and autophagy are two important and related arms of the host's first-line defense against microbial invasion. Rubicon is a RUN domain containing cysteine-rich protein that functions as part of a Beclin-1-Vps34-containing autophagy complex. We report that Rubicon is also an essential, positive regulator of the NADPH oxidase complex. Upon microbial infection or Toll-like-receptor 2 (TLR2) activation, Rubicon interacts with the p22phox subunit of the NADPH oxidase complex, facilitating its phagosomal trafficking to induce a burst of reactive oxygen species (ROS) and inflammatory cytokines. Consequently, ectopic expression or depletion of Rubicon profoundly affected ROS, inflammatory cytokine production, and subsequent antimicrobial activity. Rubicon's actions in autophagy and in the NADPH oxidase complex are functionally and genetically separable, indicating that Rubicon functions in two ancient innate immune machineries, autophagy and phagocytosis, depending on the environmental stimulus. Rubicon may thus be pivotal to generating an optimal intracellular immune response against microbial infection.     

The Harlequin ladybird continues to invade southeastern Europe

The ladybird Harmonia axyridis (Pallas) is considered one of the most serious invasive species around the globe. It has spread all over North America and Western Europe, while data from southeastern Europe, especially in the Mediterranean region, are scarce. In this study we present the first confirmed data of the spread of H. axyridis throughout Croatia. Specimens were sampled and identified during the period 2008–2010. The species was recorded at 18 localities in all three colour forms in various habitat types. Light trapping was found to be a satisfactory method for collecting H. axyridis. Since there is no evidence to suggest the deliberate introduction of H. axyridis in Croatia, it can be assumed that it has spread southwards from Central and Eastern Europe, and that it will probably continue to spread. Further investigations should focus on monitoring and detailed mapping of H. axyridis in Croatia and neighbouring countries, especially in the Mediterranean region, to determine whether stable populations are present.     

Influence of cytology development on frequency of pre-cancerous lesions and cervical cancer in east Croatia, 1978-2001

We analyzed the influence of cytology development to frequency of precancerosa (Cervical intraepithelial neoplasia grade 3 - CIN 3) and cervical cancer. The number of examined Pap smears increased significantly in the analyzed period. The calculated linear trend shows an average four-year increase of 17,283.35 smears. The number of detected CIN 3 increased accordingly. The calculated linear trend shows an average four-year increase by 45.03 and decrease of the rate of 0.07. A slight increase in cervical cancer was also noticed. The calculated linear trend shows an average four-year increase in cancer by 1.6 and decrease in the rate of 0.51. Analyses of cervical cancer by stages showed an increase in number of stage I and decrease of other stages. The calculated linear trend shows an average four-year increase of stage I by 4.94 or decrease in other stages of cervical cancer of 3.29 respectively. The rate of cervical cancer stage I decreased by 0.11 and of other stages by 0.39. Further analyses of the stage I showed that the linear trend of IA stage had an average four-year increase by 5.40 and decrease in stage IB of 0.48. The rate of the cervical cancer stage IA increased by 0.02, whereas the rate of IB decreased by 0.13. Cytology development in our country has resulted in detection of higher number of CIN 3 and the earliest stage (IA) of cervical cancer whereas the number of other stages (IB, II, III, IV) has decreased. However, a total number of cervical cancers haven't changed over the whole period. Thus, it is obvious that opportunistic program of detection, which has been using in Croatia, could not decrease frequency of cervical cancer. In order to achieve it, well-organized national program of detection is needed.     

Sequence variation in CYP51A from the Y strain of Trypanosoma cruzi alters its sensitivity to inhibition

CYP51 (sterol 14α-demethylase) is an efficient target for clinical and agricultural antifungals and an emerging target for treatment of Chagas disease, the infection that is caused by multiple strains of a protozoan pathogen Trypanosoma cruzi. Here, we analyze CYP51A from the Y strain T. cruzi. In this protein, proline 355, a residue highly conserved across the CYP51 family, is replaced with serine. The purified enzyme retains its catalytic activity, yet has been found less susceptible to inhibition. These biochemical data are consistent with cellular experiments, both in insect and human stages of the pathogen. Comparative structural analysis of CYP51 complexes with VNI and two derivatives suggests that broad-spectrum CYP51 inhibitors are likely to be preferable as antichagasic drug candidates.     

Plastid transformation in greening scales of the onion bulb (Allium cepa,Alliaceae)

The greening of the upper part of the outerAllium cepa L. bulb scales, in particular along the vascular regions, is limited to the hypodermal cells in which typical leucoplasts are transformed to normal and functional chloroplasts. This process is light dependent and cannot afterwards be reversed or modified by darkness. The changes in fine structure are described and briefly discussed.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday and 55 years after the publication of his Grundriß der Cytologie.     

Regression analysis of the spontaneous spike activity of neurons in snail ganglia

Regression analysis of the spontaneous spike activity of neurons in Helix pomatia was carried out with the aim to establish the statistical parameters of this activity under constant experimental conditions and during longer time intervals. The activity of 38 randomly chosen neurons in visceral and parietal ganglia, penetrated by microelectrodes and activated either endogenously by pacemaker potentials or by synaptic inputs, was recorded during time intervals lasting from 20 min to 3 h. The main results of the statistical analyses are presented in the table where the parameters of both cell types are listed. The validity of the regression analysis applied here is discussed from the point of the possibility it offers for carrying on the data processing quickly and without applying complex calculating means. The results are also considered regarding the current interest of our research group.     

Vegetation of the <Emphasis Type="Italic">Hydrochari-Lemnete</Emphasis> and <Emphasis Type="Italic">Potametea</Emphasis> classes in the Danube-Tisza-Danube hydrosystem (Serbia)

Aquatic vegetation of Hydrochari-Lemnetea and Potametea classes in the Danube-Tisza-Danube hydrosystem (Hs DTD) was studied in 2009–2012, by applying the standard Braun-Blanquet method. The canal network vegetation comprises 14 associations, with Trapetum natantis and Ceratophylletum demersi being the most widely distributed. Hs DTD is also a habitat for several important endangered species, which serve as edificators of the following phytocenoses: Nymphaeetum albae, Nymphaeetum albo-luteae, Nymphoidetum peltatae, Trapetum natantis, Lemno-Spirodeletum, Salvinio-Spirodeletum polyrrhizae, Lemno-Utricularietum vulgaris, Potametum nodosi, Myriophyllo-Potametum and Najadetum marinae. In the studied vegetation, we also found an invasive phytocenosis Elodeetum canadensis that did not have an expanding tendency, and Ceratophyllo demersi-Vallisnerietum spiralis that had this tendency, which made monitoring its stands necessary. Physico-chemical analyses of water, conducted at localities in which the studied phytocenoses thrive, revealed that the development and distribution of most phytocenoses is closely linked with specific habitat conditions. Among the studied parameters, the most significant for the phytocenoses differentiation were: pH, alkalinity, COD-MnO₄, BOD₅, NO ₃ ^? , NO ₂ ^? , PO ₄ ^3? and the concentration of total phosphorus.     

Differential induction of regulatory genes during mesoderm formation in Xenopus laevis embryos

Mesoderm development in Xenopus laevis depends on inductive cell interactions mediated by diffusible molecules. The mesoderm inducer activin is capable of redirecting the development of animal explants both morphologically and biochemically. We have studied the induction of four regulatory genes, Mix. 1, goosecoid (gsc), Xlim-1 and Xbra in such explants by activin, and the influence of other factors on this induction. Activin induction of gsc is strongly enhanced by dorsalization of the embryo by LiCl, while expression of the other genes is only slightly enhanced. The protein synthesis inhibitor cycloheximide (CHX) inhibits the activin-dependent induction of Xbra partially, while induction of Mix. 1 and Xlim- 1 is essentially unaffected. In contrast, gsc shows strong superinduction in the presence of activin and CHX, and can be induced in animal explants by CHX alone. Induction and superinduction by CHX have previously been observed for immediate early genes in a variety of systems, notably for the activation of c-fos expression by serum stimulation, but have not been reported in early amphibian embryos. © 1993Wiley-Liss, Inc.