Possible Interactions within a Methanotrophic-Heterotrophic Groundwater Community Able To Transform Linear Alkylbenzenesulfonates

The relationships and interactions within a methanotrophic-heterotrophic groundwater community were studied in a closed system (shake culture) in the presence of methane as the primary carbon and energy source and with the addition of the pure linear alkylbenzenesulfonate (LAS) congener 2-[4-(sulfophenyl)]decan as a cometabolic substrate. When cultured under different conditions, this community was shown to be a stable association, consisting of one obligate type II methanotroph and four or five heterotrophs possessing different nutritional and physiological characteristics. The results of experiments examining growth kinetics and nutritional relationships suggested that a number of complex interactions existed in the community in which the methanotroph was the only member able to grow on methane and to cometabolically initiate LAS transformation. These growth and metabolic activities of the methanotroph ensured the supply of a carbon source and specific nutrients which sustained the growth of four or five heterotrophs. In addition to the obligatory nutritional relationships between the methanotroph and heterotrophs, other possible interactions resulted in the modification of basic growth parameters of individual populations and a concerted metabolic attack on the complex LAS molecule. Most of these relationships conferred beneficial effects on the interacting populations, making the community adaptable to various environmental conditions and more efficient in LAS transformation than any of the individual populations alone.     

Lenticel hypertrophy in shoot cultures of Ceratonia siliqua L.

Numerous white surface proliferations appeared in cultures of Ceratonia siliqua L. grown three to four weeks on medium containing 0.5 mg l^-1 BA and 0.1 mg l^-1 IBA. It was histologically confirmed that these proliferations were hypertrophied lenticels. Proliferations appeared first at the basal shoot internode and gradually spread acropetally, covering eventually the whole shoot except the uppermost internodes. Increase of BA concentration in the medium increased both the number of hypertrophied lenticels per shoot and the shoot multiplication index.Abbreviations BA 6-benzylamino-purine - IBA indole-3-butyric acid Dubravka Bojovi-Cveti deceased July 8, 1991.     

A piRNA pathway primed by individual transposons is linked to de novo DNA methylation in mice

piRNAs and Piwi proteins have been implicated in transposon control and are linked to transposon methylation in mammals. Here we examined the construction of the piRNA system in the restricted developmental window in which methylation patterns are set during mammalian embryogenesis. We find robust expression of two Piwi family proteins, MIWI2 and MILI. Their associated piRNA profiles reveal differences from Drosophila wherein large piRNA clusters act as master regulators of silencing. Instead, in mammals, dispersed transposon copies initiate the pathway, producing primary piRNAs, which predominantly join MILI in the cytoplasm. MIWI2, whose nuclear localization and association with piRNAs depend upon MILI, is enriched for secondary piRNAs antisense to the elements that it controls. The Piwi pathway lies upstream of known mediators of DNA methylation, since piRNAs are still produced in dnmt3L mutants, which fail to methylate transposons. This implicates piRNAs as specificity determinants of DNA methylation in germ cells.     

Alcohol dependence and polymorphisms of serotonin-related genes: association studies

Variations in 5HT-related genes contribute to the alterations of serotonergic neurotransmission, which is implicated in the etiopathology of alcoholism. In this preliminary study we have tested polymorphisms of genes involved in 5HT transport and turnover for their association with alcohol dependence. A case group of males with type 2 alcoholism (N=59) and a control group of healthy males (N=282), both of Croatian origin, were analyzed for the frequency distribution of polymorphisms in 5HT transporter (5HTT-VNTR2, 5HTT-LPR), monoamine oxidase A (MAOA-uVNTR) and B (MAOB-A/G) and tryptophan hydroxylase 1 (TPH1 A218C) and 2 (TPH2 G-703T) genes. An increase in the frequencies of 10-repeat allele (p = 0.010; OR = 1.73; 95% CI = 1.14-2.60) and 10/10 genotype (p = 0.006; OR = 2.57; 95% CI = 1.32-5.00) of the 5HTT-VNTR2 polymorphism was found in alcoholic patients. No differences between case and control groups were observed for the other tested polymorphisms. Present results support earlier studies implicating the role of 5HTT gene in alcoholism. The increase of sample size (in progress) is expected to enable search of more subtle differences, as well as re-evaluation of these preliminary findings.     

Hyperserotonemia in autism: the potential role of 5HT-related gene variants

Increased platelet serotonin level (PSL) has been consistently found in a portion of autistic patients. Suggested mechanisms for hyperserotonemia in autism have been increased synthesis of serotonin (5HT) by tryptophan hydroxylase (TPH), increased uptake into platelets through 5HT transporter (5HTt), diminished release from platelets through 5HT2A receptor (5HT2Ar) and decreased metabolism by monoamine oxydase (MAOA). The allelic influence of genes, encoding the mentioned 5HT elements, on PSL was investigated in 63 autistic subjects. Our study shows that 5HTt-LPR and -1438AG 5HT(2Ar) genotypes did not significantly affect PSL. However, significantly higher PSLs were observed in subjects with "cc" genotype of a218c TPH and subjects with "4" genotype of uVNTR MAOA. In addition, when TPH-cc and MAOA-4 were combined as "high 5HT" genotypes, a correlative increase in PSL was observed with the increase in the number of "high 5HT" genotypes. These results suggest a possible synergistic effect of genes regulating 5HT synthesis/degradation in dysregulation of the peripheral 5HT homeostasis of autistic patients.     

Changes of phytoplankton functional groups in a floodplain lake associated with hydrological perturbations

During the past decade, basic hydrological conditions of a floodplain lake in the middle Danube section have been altered with long-lasting extremely high flooding. The objective of the paper is to show the effectiveness of the functional approach to explain phytoplankton changes associated with hydrological events. Intensity and duration of flooding were qualified as the primary cause for the changes of functional groups. Flooding phase was characterised by diatoms (B, C, D, P, T _B ) tolerant to water column mixing. Due to the dilution and washout effect their biomass was low during the long-lasting flooding despite their input from the river. Co-occurrence of coccoid green algae (X1, J, F) was associated with turbid and mixed waters. High-nutrient concentrations and water column stability during the long-term dry conditions led to the dominance and high biomass of cyanobacteria. Low-nitrogen H1 group was particularly sensitive to stress caused by flooding, while filamentous N₂-fixing (S _N ) and non N₂-fixing species (S1) showed tolerance to short-term flooding. The development of euglenoids and dinoflagellates (W1, W2, L _O ) was also associated with dry conditions and seasonal changes in autumn. The functional classification allows representing of the hydrological phases which characterise the phytoplankton succession in highly disturbed river-floodplain systems.     

An archeozoological analysis of teeth of lower jaw of pigs coming from the Kostolac culture (3,250-3,000 B.C.), originating from Vucedol,including comparison with recent

An investigation has been made within the expertise regarding teeth of 10 left halves of mandibles of recent sows as well as teeth of 18 pig mandibles originating from Kostolac culture (3,250-3,000 B.C.) from Vucedol archaeological location. TWS (Tooth Wear Stage) has been determined at all molars, according to Grant method and a corresponding numerical equivalent has been added, so MWS (Mandibular Wear Stage) has been obtained by summing up the above. On the basis of these values and ranges of MWS, an approximate age at the time of death has been determined for each unit. All the recent units have been older than 17 months, while the age of Kostolac units has come out to be between 14 and 17 months.     

Paraoxonase activity and concentration of indicators of lipids status in the serum of cardiac patients

In this research, we measured the activity of paraoxonase (basal and activated) enzyme, and components of lipid status components (total cholesterol, LDL cholesterol, HDL cholesterol and Apo A I) in the serum of patients, undergoing bypass surgery. We also tested how the applied EKC affected changes of defined indicators. Measuring of all the given parameters was conducted prior to the operation, 90 minutes, 1.5 hour, 6 hours, 24 hours and 72 hours, on 29 patients (11 of them did undergo myocardium revascularization with the application of EKC, while the rest of them did not). Activity of paraoxonase (both basal and activated) changes significantly during the postoperative period, in relation to pre-operative values, p < 0.05. Total cholesterol concentration is reduced in both examined groups, regardless of the application of EKC. This trend is also accompanied by LDL cholesterol concentration. On the other hand, HDL cholesterol concentration during post-operative period does not indicate any significant statistical change in relation to pre-operative values, while we noticed difference with regard to EKC application, 90 minutes after surgery. This change of lipid status indicator is partly due to heparin, a stimulator of lipoprotein lipase that was applied during the surgery. Our conclusion is that lipid profile changes significantly after the bypass surgery, mostly regardless of the application of EKC.     

Probabilistic kinetic model of slow oxidation of low-density lipoprotein: I. Theory

The microscopic probabilistic model has been introduced to explain the kinetics of very slow oxidation of low-density lipoprotein (LDL) from human plasma. The LDL oxidation, carried out in very unfavorable conditions, is assumed to be initiated by the traces of the transition-metal ions associated with the lipoprotein. The substrates for the metal-ion attack are alpha-tocopherol and the pre-formed lipid hydroperoxide. The theory assumes oscillation of the metal ions and alpha-tocopherol from the oxidized to the reduced states. In this model alpha-tocopherol acts as a pro-oxidant. The entire oxidation process consists of rare bursts of events in individual LDL particles. The reactions within the particles are treated in terms of probabilities of individual active species to participate in a specified reaction. The circular flow of the radical reactions could be visualized as circular flow of microscopic probabilities. The empirical, macroscopic quantities are quantitatively related with the microscopic probabilities, determined by a set of five adjustable parameters. The differential equations describing the initial radical generation rate and the rates of change of concentration of oxygen, hydroperoxide, co-antioxidant and trapped radicals in an LDL system are numerically solved in a finite difference approach.     

Clinical importance of significant asimptomatic bacteriuria in newborns and infants during early postnatal period

The aim of the study was to detect newborns at risk for developing renal impairment, and to point out the importance of significant asimptomatic bacteriuria in perinatal period and early infancy. Severe urinary tract anomalies are very often accompanied only by asimptomatic bacteriuria in perinatal period. Three urinalysis ware done after delivery. 212 newborns with significant asimptomatic bacteriuria underwent ultrasound examination, and were followed up to three months. Those with normal findings and with passing bacteriuria in the first 2 months were excluded. Group of 52 newborns underwent radioisotope examination. Frequency of urinary tract anomalies in newborns was 34.6%. Increased risk for renal impairment had children with urinary tract anomalies in close family, urinary tract infection or bacteriuria, EPH gestosis and prepartal symptoms of febrile infection in mother, children with IUGR, strangulated umbilical cord, prolonged jaundice and attacks of peripheral cyanosis in perinatal period.