Age-related Changes in the Insulin Receptor β in the Gerbil Hippocampus

The insulin receptor has been reported to be associated with memory formation via the hippocampus. In this study, we observed age-related changes in the insulin receptor β immunoreactivity and its protein levels in the hippocampus of gerbils of various ages in order to identify the correlation between the insulin receptor β and aging processes in the hippocampus. Insulin receptor β immunoreactivity was mainly detected in the molecular and polymorphic layers of the dentate gyrus, and in mossy fibers, Schaffer collaterals, alveus and stratum lacunosum-moleculare of the hippocampus proper (CA1-3) of gerbils at postnatal month 1 (PM 1). Insulin receptor β immunoreactivity decreased with age in all of these structures, except for the alveus. Reduction of the insulin receptor β immunoreactivity was prominent in the molecular layer of the dentate gyrus at PM 6 and in the stratum lacunosum-moleculare of the CA1 region at PM 12, while insulin receptor β immunoreactivity was decreased in other regions in the PM 18 groups. In addition, insulin receptor β protein level in the whole hippocampus was slightly increased at PM 3, and it decreased in an age-dependent manner from PM 6 to PM 24. These reductions of the insulin receptor β in the hippocampus may be associated with age-related memory deficits in gerbils.     

SH groups in the α-naphthyl acetate esterase in the thyroid of the guinea-pig

Summary The -naphthyl acetate esterase in both group I and group II thyroid cells is shown to contain SH groups since there is a decline in activity in both cell groups when certain sulfhydryl reagents [DTNB; 5,5-Dithiobis-(2-nitrobenzoic acid)-AgNO₃-Mersalyl-PCMB (parachloro mercuribenzoate)+urea] are added to the incubation media. Thus the inhibition is by far the greatest in group I cells, which also show the greatest activity after incubation in conventional media, when long fixation and storage times are used. In all cases the inhibiting effect was complete or almost completely reversed if cysteine was added to the incubation media in equivalent concentrations to the SH blocker. There were great differences among the sulfhydryl reagents used in their ability to bring about enzyme inhibition. The alkylating agents NEM (N-ethylmaleimide) and iodoacetamide had no or little effect while PCMB could only inhibit the activity of the -naphthylacetate esterase if the enzyme was denaturated with 5 m urea. The maximal inhibitory effect of PCMB was only obtained when NaCl was added to the incubation media. The most effective inhibitor was AgNO₃.     

Zooplankton in the ponds with tropical plants in the greenhouses of the Botanical Garden of the Jagiellonian University in Kraków

The presence of P. tetraurelia was found in the pond in "The Palm-House" greenhouse.     

Is neurotensin in the brain involved in thermoregulation of the monkey?

Cannulae for intracerebroventricular (ICV) infusion were implanted stereotaxically in monkeys (Macaca fasicularis) maintained post-operatively in a primate restraint chair. During each experiment, a series of physiological measures was recorded simultaneously on a polygraph which included colonic temperature, vasomotor tone, heart rate, respiratory rate, and basal metabolism as reflected by O₂ uptake. The ICV infusion in a volume of 0.5 ml of neurotensin (NT) in doses ranging from 3–150 μg produced neither a statistically significant nor consistent change in body temperature or vasomotor response. Although the highest dose of 450 μg NT infused ICV caused an immediate bradycardia and a concomitant decline in metabolic and respiratory rates, an average decline in core temperature of 0.6°C and the accompanying cutaneous vasodilation often had a latency as long as 1.0 hr. In contrast to the typical hypothermia in this species following an ICV infusion of catecholamines, implicated in the central pathways underlying thermoregulation, NT failed to elicit a coordinated set of physiological responses for heat dissipation in the monkey. Therefore, it is unlikely that this tridecapeptide plays a role in the central mechanisms mediating the control of body temperature of this primate species.     

Changes in the rate of photosynthesis accompanying the yield increase in wheat cultivars released in the past 50 years

Photosynthetic rates in different development stages were carefully investigated in 18 cultivars of winter wheat released in the period between 1945 and 1995 in the area of Beijing, China. During this period, the recorded grain yield has increased eightfold. However, when those cultivars were planted and managed in the same environment, the difference was reduced to only 36%, indicating that agronomic practices are the most important factors for grain yield. Agronomic features have changed greatly in the past 50 years, through increasing the harvest index (R²=0.89, P<0.05), shortening plant height (R²=0.77, P<0.05) and slightly increasing flag leaf areas (R²=0.45, P<0.05), which is mostly in agreement with many other researchers. In contrast to many reports, however, this study found a genetic increase in the rate of photosynthesis per unit leaf area. From the mid-stem elongation to soft dough stages, the average photosynthetic rates at saturated photosynthetic photon flux density (P_sat) increased by 44%. In the process, the stomatal conductance (g_s) also increased by 122%. Grain yield was positively related to the mean values of P_sat (R²=0.61, P<0.01) and g_s (R²=0.67, P<0.01) in the six development stages. Our experiment may suggest that increase in grain yield was associated with the elevation of leaf photosynthetic rate and stomatal conductance over the past 50 years.     

Every species is good in its season: Do the shifts in the annual temperature dynamics affect the phenology of the zooplankton species in the White Sea?

We hypothesize that shifts in the annual pattern of the environmental parameters may affect the phenology of the zooplankton especially in temperate and polar areas. Five species (cold-water: Calanus glacialis, warm-water: Centropages hamatus, Temora longicornis, Acartia longiremis, and Evadne nordmanni) were tested with regard to the annual pattern of the water temperature using the dataset of 50-year-long monitoring in the White Sea (1961–2010). The hydrological summer duration increased by 20 days during the last 50 years, as it has been tracked by an earlier warming up of 0–10-m water layer in spring. Calanus glacialis responded to these changes by the appearance of CI copepodites earlier in the season. We suggest that the earlier start and longer period of ice melt may cause a longer phytoplankton bloom and thus may promote better trophic conditions during the period of Calanus reproduction and its early development. In contrast to cold-water C. glacialis, the phenology and abundance of warm-water copepods have not changed significantly. Both the timings of autumn cooling and average summer temperature remained relatively stable since the beginning of observations resulting in steady conditions during the reproductive period of warm-water species. Prolongation of summer had no effect on their reproduction.     

Variation in the cell cycle time in the crypts of lieberkühn of the mouse

The durations of the phases of the cell cycle were measured at different levels in the jejunal crypts of male Balb/c mice. A mean cell cycle time of 12.3 h was found for the whole crypt. In cell positions 1 and 2, the cell cycle time was 16.7 h, and this time steadily decreased to a value of between 10 and 11 h for cell positions above 11. It is concluded that basally situated crypt cells in the mouse are cycling relatively slowly, and that they form the functional stem cell pool for the crypt. These cells may also compose the potential stem cell pool which repopulates the crypt after death of proliferative cells.     

Change in the power of EEG activity in the α range in response to tonic nociceptive stimulation of the distal joint of the little finger

Examination of 12 healthy volunteers aged 20–56 years was performed to study the EEG changes caused by a tonic squeeze of the distal joint of the little finger of the left and then the right hand. This stimulation caused painful sensations of different intensity (pain on the right was stronger). Spectral power was measured in the ( ₁ (8–10.5 Hz) and (₂ ranges (10.5–13 Hz) under different conditions. Weak pain led to an increase in the power of the (₁ and ₂ ranges in the occipital regions. With strong pain, the power of ₁ waves increased bilaterally in the posterior regions (O ₁, O ₂, T ₆), as well as in the left frontal region (F ₃, F ₇). The powers of the ₁ and ₂ ranges substantially increased relative to the background level after the strong nociceptive stimulation ceased. This finding testified to a latent and inertial character of its effect on the -wave parameters.Translated from Fiziologiya Cheloveka, Vol. 31, No. 2, 2005, pp. 77–84.Original Russian Text Copyright © 2005 by Garkavenko, Gorkovenko, Mankovskaya, Shevko, Lyskov, Kostyukov.     

Plakophilins—hard work in the desmosome,recreation in the nucleus?

The linkage of the different types of cytoskeletal proteins to cell adhesion structures at the cytoplasmic membrane and the connection of these contact sites to corresponding sites of adjacent cells is a prerequisite for integrity and stability of cells and tissues. The structurally most prominent types of such cell-cell adhesion complexes are the desmosomes (maculae adhaerentes), which are found in all epithelia and certain non-epithelial tissues. As an element of the cytoskeleton, intermediate filaments are connected to the adhesive desmosomal transmembrane proteins by the cytoplasmic desmosomal plaque proteins. At least three different types of proteins are found in the desmosomal plaque, one of which is represented by the plakophilins, a recently described sub-family of sequence-related armadillo-repeat proteins. Consisting of three isoforms, plakophilins (plakophilin 1 to 3, PKP 1 to 3) are located in all desmosomes in a differentiation-dependent manner. While PKP 2 and PKP 3 are part of almost all desmosome-bearing cell types (PKP 2 except for differentiated cells of stratified epithelia and PKP 3 for hepatocytes and cardiomyocytes), PKP 1 is restricted to desmosomes of cells of stratified and complex epithelia. Besides the architectural function that plakophilins seem to fulfill in the desmosomes, at least PKP 1 and 2 are also localized in the nucleus independently of any differentiation-related processes and with an up to now enigmatic function in this compartment. In the following article we want to summarize the current knowledge concerning structure, function and regulation of the plakophilins that has been achieved during the last decade.     

Diversity of fish species in the trawl catches in the southeastern Barents Sea in 1980–2008

Analysis of trawl catches in the southeastern Barents Sea was performed for the period of 1980–2008. One lamprey and 48 fish species were defined, including 38 marine fish species, 8 anadromous and amphidromous species, and 1 freshwater species. The ichthyofauna of several areas of the southeastern Barents Sea was described (Cheshskaya Inlet, Pomorskiy Strait, southeastern Pechora Sea, Pechora Sea, Khaipudyrskaya Inlet and adjacent areas). Biodiversity indexes and Shannon Index were applied to describe the species diversity. Cluster analysis was applied to compare the species lists from different areas. Multiyear dynamics of ichthyofauna was studied. The tendency of geographical range expansion eastward was observed for boreal species.     

Passive Detection of Biological Aerosols in the Atmosphere with a Fourier Transform Instrument (FTIR)—the Results of the Measurements in the Laboratory and in the Field

Fourier Transform Infrared Radiation (FTIR) spectroscopy is one of the most powerful methods for the detection of gaseous constituents, aerosols, and dust in planetary atmospheres. Infrared spectroscopy plays an important role in searching for biomarkers, organics and biological substances in the Universe. The possibility of detection and identifications with FTIR spectrometer of bio-aerosol spores (Bacillus atrophaeus var. globigii=BG) in the atmosphere is discussed in this paper. We describe the results of initial spectral measurements performed in the laboratory and in the field. The purpose of these experiments was to detect and to identify bio-aerosol spores in two conditions: 1) In a closed chamber where the thermal contrast between the background and aerosols was large, and 2) In open air where the thermal contrast between the background and aerosols was small. The extinction spectrum of BG spores was deduced by comparing our measurements with models, and other measurements known from the literature. Our theoretical and experimental studies indicate that, during passive remote sensing measurements, it is difficult-but possible to detect and to identify bio-aerosol clouds by their spectral signatures. The simple spectral analysis described in the paper can be useful for the detection of various kinds of trace aerosols-not only in the Earth's atmosphere, but also during planetary missions in the environments of other astronomical objects such as planets, comets etc. We expect that the interpretation of data from spectrometric sounding of Venus and Mars during the current missions Mars and Venus Express, and later during the Rosetta mission will benefit from our experimental work and numerical modelling.     

Does the difference in the timing of eclosion of the fruit fly Drosophila melanogaster reflect differences in the circadian organization?

The eclosion rhythm of a laboratory population of Drosophila melanogaster was studied under 12h light, 12h dark (LD 12:12) cycles. Although most of the flies were found to eclose just after “lights on” in LD 12:12, termed within gate (WG) flies, a few flies were found to eclose nearly 10h after peak eclosion, termed outside gate (OG) flies. The circadian parameters of the clocks controlling oviposition rhythms in the WG and the OG flies were estimated to understand the cause of such differences in the timing of eclosion. The distribution of the fraction of individual flies exhibiting single, multiple, and no significant period in the WG flies was significantly different from distribution in the OG flies. Compared to the WG flies, more OG flies were found to exhibit oviposition rhythm with multiple periodicity, whereas more WG flies exhibited an oviposition rhythm with a single significant period. The fraction of flies with arrhythmic oviposition was similar in both the WG and the OG flies. Free-running period τ in constant darkness (DD) and the phase angle difference ψ in LD 12:12 for the oviposition rhythm of WG and OG flies were significantly different. These results suggest that the differences in the time of eclosion between the flies eclosing within the gate and outside the gate of eclosion are probably due to differences in the circadian system controlling eclosion, which is reflected by the differences in their oviposition rhythm. (Chronobiology International, 18(4), 601-612, 2001)     

Plasticity in fecundity highlights the females’ importance in the spiny-cheek crayfish invasion mechanism

Invasion is one of the most consequential phenomena affecting the distribution of native species. Few in number of species, European crayfish are losing the competition with introduced North American crayfish. The spiny-cheek crayfish, Orconectes limosus, is an outstanding example, successfully competing against the native narrow-clawed crayfish, Astacus leptodactylus. For four years, we collected data regarding crayfish occurrences, their relative abundance, and the structure of populations in the ongoing colonisation process of O. limosus in the lower Danube. The mature females of both invasive and indigenous crayfish species were analysed with respect to biometry and production of oocytes in relation to the dynamics of invasion. The interspecific comparisons showed no significant differences regarding body size, with an average of approximately 102 mm total length and 31 g wet weight for both species. However, the fecundity of the indigenous species was found to be constant throughout the investigated area, whereas the number of eggs produced by the invasive females was significantly increased at the active front of the invasion. The maximum number of ovarian eggs found was 887 and 1156 in the indigenous species and the invasive species, respectively. We propose the scenario that the invasive species, which carries the deadly crayfish plague, creates an ecological advantage by reducing the populations of indigenous crayfish. Subsequently, the invasive females opportunistically use the available resources to enhance their fecundity, resulting in the acute growth of populations. However, the long-term competitiveness and colonisation success of O. limosus still remain in question.