The sex chromatin in five species of hamsters

The hamster species of the genus Mesocricetus, like mammals in general, display a sexual dimorphism of sex chromatin bodies. Cricetulus griseus and Cricetus cricetus do not show such nuclear sex dimorphism, probably because of the fact that the duplications in the sex chromosomes stem from translocations of autosomal segments, which resulted in the reduction of the size differences between X and Y. In the Mesocricetus species, a relatively high frequency of nuclei with two sex-chromatin bodies of different size, resulting probably from heterochromatinization of one whole X chromosome, and of half of its homologue.     

Interspecific hybrids between Romanian and Kurdistan hamsters

From crossings between Mesocricetus brandti and Mesocricetus newtoni 23 hybrids were obtained which presented characters intermediate between the parents and which were completely sterile. The number of chromosomes in the hybrid animals (2n=40) is also intermediate between the parents and the karyotype presents two distinct chromosome sets corresponding to those in the two parent species. The regular presence of multivalents at diakinesis and metaphase I probably causes the non balanced disjunction of the genetic material, and thus, probably, the total sterility of the hybrids. The study of sex chromatin showed the existence of a sex dimorphism, the female presenting more nuclei with 1–2 sex chromatin bodies. The presence of 2 sex chromatin bodies of different sixes may be explained by the heteroehromatinization of a whole X chromosome and half of its homologue.Histological study showed that the male and female genital apparatus are intensively affected in hybrids and the spermatogenetic and oogenetic activity is generally stopped. This determines the total sterility of the hybrids.     

Ultrastructural data on a microsporidian infesting the ovaries of an araneid

Oligosporidium nov. gen. arachnicolum (Codreanu-B?lcescu, Codreanu and Traciuc, 1978) is one of the more intensively studied microsporidians from an araneid. It develops into parasitophorous vacuoles formed in the oocytes of Xysticus cambridgei from Bucharest, Romania. The uninucleated schizogonic and sporogonic stages multiply through binary fission and the dense bordered sporoblasts give rise to isolated spores.     

Amino acid composition of human liver mitochondrial membranes in normal and pathological conditions

The amino acid composition of proteins from liver mitochondrial membranes has been studied in patients with normal liver, with biliary diseases and fatty liver, with obstructive jaundice or liver cirrhosis. A characteristic pattern of the amino acid composition in patients with normal liver has been found. In the mitochondrial membranes of patients with fatty liver tryptophan and lysine were decreased while [aspartic acid plus asparagine] and [glutamic acid plus glutamine] were increased compared to their counterpart in the normal liver. In patients with obstructive jaundice of short duration (less than two months) only a slight decrease in methionine content was found, while in the case of liver cirrhosis amino acid composition was markedly changed.deceased.     

Post‐glacial patterns in vegetation dynamics in Romania: homogenization or differentiation?

Aim This paper examines eight fossil pollen datasets from Romania with the aim of exploring regional and elevational patterns in site similarity throughout the Holocene. In particular, we aim to determine whether there are clear intervals of homogenization/differentiation and to ascertain the potential driving factors. Location Romania. Methods Qualitative (pollen diagrams) and numerical methods including principal components analysis and Bray–Curtis similarity analyses were used. Results We found strong variability in the past vegetation dynamics during the Holocene. Bray–Curtis similarity analyses show large fluctuations in vegetation similarity and distinct periods of homogenization and differentiation throughout the Holocene. The magnitude and length of these periods appear quite variable in time, but the significant ones can be delimited as follows: (1) differentiation between 11,250 and 11,000 cal. yr bp , 10,000 and 9750 cal. yr bp , 6000 and 5750 cal. yr bp , 2500 and 2250 cal. yr bp , and especially over the last 200 years; and (2) homogenization between 9750 and 9500 cal. yr bp , and 2750 and 2500 cal. yr bp , with more stable periods between 9000 and 7750 cal. yr bp , 4750 and 3500 cal. yr bp , and 2000 and 1000 cal. yr bp . Main conclusions First, periods of biotic homogenization that occurred before significant anthropogenic impact on vegetation demonstrate that not all homogenization is a product of anthropogenic change: it can also be driven by natural causes. In fact, recent human impact (over the last 200 years) appears to have resulted in increased regional differentiation and not in homogenization – a result that contradicts most studies based on more modern, short‐term records. Second, both abiotic (climate and disturbance) and biotic factors are likely drivers of intervals of differentiation and homogenization. We suggest that differentiation may be triggered primarily by climate changes and disturbances (mostly natural pre‐2500 cal. yr bp and human‐induced thereafter), whereas homogenization may be driven predominantly by biotic interactions (e.g. immigration and interspecific competition). Third, this long‐term study raises awareness that assessments of pattern in vegetation homogenization/differentiation may depend on the specific time period and length of investigation. Long‐term investigations through multiple generations are likely to yield particularly useful information on the mechanisms and effects of biotic homogenization.     

Feeding behaviour of Black Sea bottom fishes: Did it change over time?

This study was designed to improve knowledge in feeding behaviour of the round goby (Apollonia melanostomus (Pallas, 1814)), the red mullet (Mullus barbatus ponticus Essipov, 1927), the whiting (Merlangius merlangus (Linnaeus, 1758)), the flounder (Platichthys flesus (Linnaeus, 1758)), the sole (Solea solea (Linnaeus, 1758)), the turbot (Psetta maeotica (Pallas, 1814)) and the starry sturgeon (Acipenser stellatus Pallas, 1771) from the north-western Black Sea. Gut content coupled with stable isotope analysis allowed describing food web variations according to species, in two seasons and at two areas located seawards the Danube River. Present results showed that most fishes have likely changed their feeding behaviour compared to past studies from the same area. Trophic niches were reduced and dietary overlap was common, as different fish species consumed the same dominant prey types. Fishes probably adapted their feeding behaviour to the increasingly low biodiversity of the Black Sea communities.     

Mollusc assemblages of the Pontian and Dacian deposits from the Topolog-Arge? area (southern Carpathian foredeep - Romania)

A better understanding of Mediterranean-Paratethys water-exchange during the Messinian Salinity Crisis has since long been hampered by the absence of a reliable time frame for the Paratethys. High-resolution magnetostratigraphic studies on the sedimentary sequences of the eastern and southern Carpathian foredeep recently resulted in an accurate chronology for the Mio-Pliocene deposits of the Dacic Basin of Romania. This allowed a straightforward correlation of the Pontian and Dacian stages to the geological time scale, which revived earlier discussions on Mediterranean-Paratethys connectivity. Here, we present Pontian and Dacian mollusc assemblages of the Getic Depression (Topolog-Arge? area, southern Carpathians) of Romania, which are incorporated in a magnetostratigraphic time frame. They indicate that a hiatus - comprising the Early Pontian - is present in the stratigraphic successions, which could be related to a base level drop of the Paratethys water column or to more local tectonic processes. The mollusc assemblages furthermore show a gradual transition at the Pontian/Dacian boundary, which is magnetostratigraphically dated at ∼4.9 Ma. This is significantly later (by more than 400 kyrs) than the Mio-Pliocene boundary in the Mediterranean sequences.     

Representatives of the genus Triploporella (Dasycladales, calcareous algae) in the Lower Cretaceous limestones of Romania

Recent studies on the Lower Cretaceous deposits located in various areas of the Romanian Carpathians resulted in the identification of several specimens of dasycladalean algae assigned to the genus Triploporella including Triploporella carpatica Bucur, Triploporella cf. praturlonii Barattolo, Triploporella cf. steinmannii Barattolo, Triploporella sp. 1, Triploporella sp. 2, and Triploporella n. sp. This paper provides arguments on their taxonomic assignment, together with discussions on the Triploporella species described in the literature and their paleobiogeographic significance.     

Gamma-glutamyltransferase,possible novel biomarker in colon diverticulosis: a case-control study

The gamma-glutamyltransferase (GGT) is recognized in medical practice as a useful indicator for the detection of liver lesions, especially those induced by the excessive consumption of alcoholic or cholesterol-associated drinks. The present study, although it includes a very small number of cases diagnosed with colon diverticulosis-diverticulitis associated with polyposis at the same intestinal level, identifies the presence of increased circulating concentrations of this enzyme in the serum. Its serum levels are tracked “dynamically” throughout a year after the diagnosis and start of the therapy. The study calls into question the release of the enzyme from the edge of the enterocytes’ brush-like edge, leading to the pathogenic disturbance of regional redox homeostasis. The hypothesis gives the circulating values of GGT predictive value for cellular oxidative stress, as well as for indirectly expressing the glutathione level in cytosol.