Elemental composition and flavonol content of <Emphasis Type="Italic">Pentaphylloides fruticosa</Emphasis> (L.) O. Schwarz in connection with plant age

The elemental composition and flavonol content of Pentaphylloides fruticosa (L.) O. Schwartz under the conditions of the Altai mountains are investigated. Some differences in the concentrations of elements and flavonols were detected in the leaves of P. fruticosa plants of different age classes corresponding to two periods of development: pregenerative (immature and virginal plants) and generative (young, middle-aged and old generative individuals). The maximum content of flavonols, in particular quercetin, in the leaves of P. fruticosa corresponds to the young generative age. A very high correlation between the flavonol content and the concentrations of Mn, Zn, Mo, and Se was revealed.     

Cardiac-restricted overexpression of extracellular matrix metalloproteinase inducer causes myocardial remodeling and dysfunction in aging mice

The matrix metalloproteinases (MMPs) play a pivotal role in adverse left ventricular (LV) myocardial remodeling. The transmembrane protein extracellular MMP inducer (EMMPRIN) causes increased MMP expression in vitro, and elevated levels occur in patients with LV failure. However, the direct consequences of a prolonged increase in the myocardial expression of EMMPRIN in vivo remained unexplored. Cardiac-restricted EMMPRIN expression (EMMPRINexp) was constructed in mice using the full-length human EMMPRIN gene ligated to the myosin heavy chain promoter, which yielded approximately a twofold increase in EMMPRIN compared with that of the age/strain-matched wild-type (WT) mice; EMMPRINexp (n=27) and WT (n=33) mice were examined at 3.2+/-0.1 or at 13.3+/-0.5 mo of age (n=43 and 26, respectively). LV end-diastolic volume (EDV) was similar in young EMMPRINexp and WT mice (54+/-2 vs. 57+/-3 microl), but LV ejection fraction (EF) was reduced (51+/-1 vs. 57+/-1%; P<0.05). In old EMMPRINexp mice, LV EDV was increased compared with WT mice values (76+/-3 vs. 58+/-3 microl; P<0.05) and LV EF was significantly reduced (45+/-1 vs. 57+/-2%; P<0.05). In EMMPRINexp old mice, myocardial MMP-2 and membrane type-1 MMP levels were increased by >50% from WT values (P<0.05) and were accompanied by a twofold higher collagen content (P<0.05). Persistent myocardial EMMPRINexp in aging mice caused increased levels of both soluble and membrane type MMPs, fibrosis, and was associated with adverse LV remodeling. These findings suggest that EMMPRIN is an upstream signaling pathway that can play a mechanistic role in adverse remodeling within the myocardium.     

Stabilization of beam instability by a local instability developing due to a wave-wave interaction

A new mechanism for stabilization and suppression of beam instabilities is proposed. This mechanism, which is based on the stochastic instability of a wave-wave interaction process, plays a particularly important role in plasma systems with a small region of interaction between the beam particles and the excited waves.     

Protein enrichment in plant by fusaria

Five micro fungi of the type Fusaria were investigated for the bioconversion of agricultural piant wastes. One strain was favoured for protein enrichment in heat-pretreated straw, also improving digestibility in the fodder produced. The influence of the chitin content in the fodder was studied, and for calculating raw-protein from the organic nitrogen content an additional factor of 0.92 was proposed to the known factor of 6.25. For the application of Fusaria strains in bioconversion processes a prognosis a prognosis was offered.     

Characteristics and application of S1–P1 nucleases in biotechnology and medicine

3′–nucleases/nucleotidases of the S1–P1 family (EC 3.1.30.1) are single–strand–specific or non-specific zinc–dependent phosphoesterases present in plants, fungi, protozoan parasites, and in some bacteria. They participate in a wide variety of biological processes and their current biotechnological applications rely on their single–strand preference, nucleotide non-specificity, a broad range of catalytic conditions and high stability. We summarize the present and potential utilization of these enzymes in biotechnology and medicine in the context of their biochemical and structure–function properties. Explanation of unanswered questions for bacterial and trypanosomatid representatives could facilitate development of emerging applications in medicine.     

Physiological Responses of <Emphasis Type="Italic">Matricaria chamomilla</Emphasis> to Potassium Nitrate Supply and Foliar Application of Ethephon

The study is focused on changes in metabolism of Matricaria chamomilla, caused by potassium nitrate (KNO₃) supplement and foliar application of an ethylene releaser—ethephon (ET). ET-treated plants were irrigated with 0, 9, 18 or 27 mmol of KNO₃ during 1 week and simultaneously treated with ET. The same procedure was followed with ET non-treated plants, where an equal amount of distilled water was sprayed on leaves. Nitrogen addition into soil substrate caused considerable increment in dry matter content, nitrate accumulation and amino acids synthesis. After ET application, a positive correlation between KNO₃ supply and stress-related parameters, such as superoxide radical, hydrogen peroxide and malondialdehyde was found. Experimental conditions led to a sharp decrease in herniarin level, which was accompanied with increasing content of its glycosidic precursors in ET-treated plants. The observations indicated that higher doses of nitrate suppressed the stimulation effect of ET on the production of salicylic acid and umbelliferone, metabolites, which are involved in stress responses in plants. In the case of umbelliferone, ET strongly induced its accumulation in comparison with ET non-treated variants.     

Perinatal mortality in term and preterm twin and singleton births.

Although, in general, twins have higher perinatal mortality rates than singletons, preterm twins have lower perinatal mortality rates than singletons of the same birth weight or gestational age. This study investigated the hypotheses that this paradoxical twin advantage: 1) is due to gestational age distribution differences between the singleton and twin populations, and 2) is due to increased likelihood of birth having occurred in a tertiary perinatal center. A pre-existing, time-limited data set of all births in the province of Ontario in odd years between 1979 and 1985 was chosen for this study because of the large sample size (n = 618,579). Multivariable logistic regression of the relationship between perinatal mortality and twin status was controlled for mother's age, hospital level and gestational age. Findings confirm the lower mortality of preterm twins. After controlling for level of hospital of birth this difference remained, suggesting that level of hospital of birth was not a major factor responsible for the twin advantage. Analyses in which gestational age was standardized indicate that, for those whose gestational age was less than 2 SD below the mean for their particular group (twin or singleton), twins were actually at higher risk than singletons. These results support hypothesis 1 and do not strongly support hypothesis 2. The results also support earlier authors' suggestions that the definition of term birth should be different for twins and singletons