Enzymic synthesis ofL-Lysine fromDL-α-Amino-ε-caprolactam by new microbial strains

The production of L-lysine fromDL-α-amino-ε-caprolactam (DL-ACL) by new strains producingL-α-amino-ε-caprolactamase and aminocaprolactam racemase is described. Optimal conditions for hydrolysis ofL-ACL byCryptococcus sp. and for racemization of ACL by cells of a strain isolated in nature and identified asPseudomonas sp. were determined. Synthesis ofL-α-amino-ε-caprolactamase is induced byDL-ACL orL-lysine with the same effectivity. A positive effect of phosphates (potassium salts) on reduction of the induction lag was detected, the synthesis of this enzyme was found to be repressed by glucose and some possibilities of the reversion of this repressive effect were demonstrated. Under conditions optimal for the production of both enzymes a quantitative theoretical conversion of 10 % aqueousDL-ACL toL-lysine by a mixture of native cells in a mass ratio of 1: 2 (producer of ACL-hydrolase to producer of ACL-racemase) occurred in 8 h at 40 °C and pH 8.0     

Iron metabolism in iron-deficient male quail

1. Male quails submitted 20 and 120 days to a low iron diet (7 ppm) were compared to female laying quails, exposed for 30 days to the same low iron regime, in order to compare the response of the iron metabolic control under a single (erythropoiesis) or a doubled (erythropoiesis and egg formation) iron demand. 2. Iron deposit in storage organs, the classical hematology and the intestinal iron absorption were analyzed in these animals. 3. In males, after 120 days, the iron deposits were reduced 50 and 75%, but hematological values (hematocrit and hemoglobin concentration) were normal, although in laying quails, after 30 days, an anemic condition was evident in both blood parameters and iron deposits, provoking an iron deficient erythropoiesis. 4. The enhancement of the intestinal iron uptake, confirms the anemic character of these birds.     

Effect of precursors on biosynthesis of monensins A and B

Precursors of monensins (acetate, propionate, butyrate, isobutyrate) affect the total production and the relative proportion of monensins A and B. Addition of propionate into the fermentation medium causes a prevalence of monensin B whereas butyrate and isobutyrate stimulate the production of monensin A and suppress the production of monensin B.     

Intraspecific genetic variation of a Fagus sylvatica population in a temperate forest derived from airborne imaging spectroscopy time series

1. The growing pace of environmental change has increased the need for large‐scale monitoring of biodiversity. Declining intraspecific genetic variation is likely a critical factor in biodiversity loss, but is especially difficult to monitor: assessments of genetic variation are commonly based on measuring allele pools, which requires sampling of individuals and extensive sample processing, limiting spatial coverage. Alternatively, imaging spectroscopy data from remote platforms may hold the potential to reveal genetic structure of populations. In this study, we investigated how differences detected in an airborne imaging spectroscopy time series correspond to genetic variation within a population of Fagus sylvatica under natural conditions.
2. We used multi‐annual APEX (Airborne Prism Experiment) imaging spectrometer data from a temperate forest located in the Swiss midlands (Laegern, 47°28'N, 8°21'E), along with microsatellite data from F. sylvatica individuals collected at the site. We identified variation in foliar reflectance independent of annual and seasonal changes which we hypothesize is more likely to correspond to stable genetic differences. We established a direct connection between the spectroscopy and genetics data by using partial least squares (PLS) regression to predict the probability of belonging to a genetic cluster from spectral data.
3. We achieved the best genetic structure prediction by using derivatives of reflectance and a subset of wavebands rather than full‐analyzed spectra. Our model indicates that spectral regions related to leaf water content, phenols, pigments, and wax composition contribute most to the ability of this approach to predict genetic structure of F. sylvatica population in natural conditions.
4. This study advances the use of airborne imaging spectroscopy to assess tree genetic diversity at canopy level under natural conditions, which could overcome current spatiotemporal limitations on monitoring, understanding, and preventing genetic biodiversity loss imposed by requirements for extensive in situ sampling.

     

Complementary Roles of the Hippocampus and the Dorsomedial Striatum during Spatial and Sequence-Based Navigation Behavior

We investigated the neural bases of navigation based on spatial or sequential egocentric representation during the completion of the starmaze, a complex goal-directed navigation task. In this maze, mice had to swim along a path composed of three choice points to find a hidden platform. As reported previously, this task can be solved by using two hippocampal-dependent strategies encoded in parallel i) the allocentric strategy requiring encoding of the contextual information, and ii) the sequential egocentric strategy requiring temporal encoding of a sequence of successive body movements associated to specific choice points. Mice were trained during one day and tested the following day in a single probe trial to reveal which of the two strategies was spontaneously preferred by each animal. Imaging of the activity-dependent gene c-fos revealed that both strategies are supported by an overlapping network involving the dorsal hippocampus, the dorsomedial striatum (DMS) and the medial prefrontal cortex. A significant higher activation of the ventral CA1 subregion was observed when mice used the sequential egocentric strategy. To investigate the potential different roles of the dorsal hippocampus and the DMS in both types of navigation, we performed region-specific excitotoxic lesions of each of these two structures. Dorsal hippocampus lesioned mice were unable to optimally learn the sequence but improved their performances by developing a serial strategy instead. DMS lesioned mice were severely impaired, failing to learn the task. Our data support the view that the hippocampus organizes information into a spatio-temporal representation, which can then be used by the DMS to perform goal-directed navigation.     

Biogeographical patterns and Rapoport's rule in southeastern Pacific benthic polychaetes of the Chilean coast

Recently three biogeographical units were identified along the Chilean coast (the Magellanic Province, an Intermediate Area, and the Peruvian Province), however few studies have focused on the factors and dynamic processes that formed these spatial units (e.g. Rapoport's rule and its causal mechanisms). In this study we used benthic polychaetes of the Chilean coast to evaluate patterns of latitudinal distribution and species richness, and the existence of the three main biogeographical provinces described for the Chilean coast. Additionally, we evaluated the latitudinal Rapoport effects and geometric constraint as a null hypothesis explaining the species richness distribution.
We found that benthic polychaete diversity increased towards southern latitudes. The cluster and ordination (non-metric MultiDimensional Scaling, nMDS) analyses of the distribution data, presented only two statistically significant (bootstrapping techniques) biogeographic provinces along the Chilean coast, with a break occurring between 41° and 42°S. While, our results did not support a latitudinal Rapoport effect, they did support the view that latitudinal Rapoport effects are a local phenomenon, occurring only for the Northeastern Pacific marine taxa. The relationship between latitudinal range extent and mean latitude indicated the existence of two hard boundaries at either extreme of the Chilean coast, limiting the geographical ranges of the species. However, geometric constraints tested using a Monte Carlo simulation approach showed a weak level of mid-domain effect on species richness. Finally, we propose that geometric constraint together with the geomorphology and historical characteristics of the Chilean coast explain the biogeographical patterns of benthic polychaete taxa in Chile.     

Radiosensitizing and damaging effects of hyperthermia on different biological systems. Ehrlich ascites carcinoma cells

The cytotoxic and radiosensitizing effects of hyperthermia was shown on Ehrlich ascites tumor cells heated in vitro. The effect of hyperthermia resulted in the formation of local lesions in membranes of dying cells.     

Selection of HLA compatible donors for patients with HLA antibodies

A strain of 1,507 typised donors enables 15.97 average donors to be selected for a thrombocyte transfusion in one of 75 patients selected at random with HLA antibodies being previously determined (1 to 66 donors per patient). HLA compatible donors were found for 72 patients (97.33 per cent). More than 5 HLA compatible donors could be found for 58 patients. The high number of compatible donors is based on the fact that among 1,507 donors there were 156 HLA homozygotes and 556 donors with 3 HLA-A or B-antigens respectively. Compatibility in the ABO-system was not taken into account.