Behavioral and biochemical evidence for serotonergic actions of tetrahydro-β-carbolines

In two groups of rats trained to discriminate LSD (0.1 mg/kg or 0.24 mg/kg) from saline, tetrahydro-β-carboline (THBC; 1–12 mg/kg as free base) and its derivative 6-methoxy-THBC (1–12 mg/kg as free base) substituted partially for LSD. The substitution of THBC for 0.1 mg/kg of LSD was analyzed further with antagonism tests in 16 animals and was attenuated by the serotonin (5-HT) antagonist BC-105 (pizotifen; 3 mg/kg) but not by the dopamine (DA) antagonist haloperidol (0.1 mg/kg). It was abolished by pre-treatment with the 5-HT synthesis inhibitor p-chlorophenylalanine (100 mg/kg/day for 3 days). In addition, THBC was found to inhibit ³H-LSD binding to homogenates of rat frontal cortex with an IC₅₀ value of 4 μM which is similar to that previously reported for other 5-HT agonists. These data indicate that THBCs exert potent 5-HT agonist actions. Since THBCs have recently been found in mammalian brain and other tissues, the present results are of interest in relation to a possible role of these substances in endogenous psychosis.     

Blood—Brain Barrier Glucose Transporter

Abstract : The transport of glucose across the blood-brain barrier (BBB) is mediated by the high molecular mass (55-kDa) isoform of the GLUT1 glucose transporter protein. In this study we have utilized the tritiated, impermeant photolabel 2-N-[4-(1-azi-2,2,2-trifluoroethyl)[2-³H]propyl]-1,3-bis(d -mannose-4-yloxy)-2-propylamine to develop a technique to specifically measure the concentration of GLUT1 glucose transporters on the luminal surface of the endothelial cells of the BBB. We have combined this methodology with measurements of BBB glucose transport and immunoblot analysis of isolated brain microvessels for labeled luminal GLUT1 and total GLUT1 to reevaluate the effects of chronic hypoglycemia and diabetic hyperglycemia on transendothelial glucose transport in the rat. Hypoglycemia was induced with continuous-release insulin pellets (6 U/day) for a 12- to 14-day duration ; diabetes was induced by streptozotocin (65 mg/kg i.p.) for a 14- to 21-day duration. Hypoglycemia resulted in 25-45% increases in regional BBB permeability-surface area (PA) values for d -[¹⁴C]glucose uptake, when measured at identical glucose concentration using the in situ brain perfusion technique. Similarily, there was a 23 ± 4% increase in total GLUT1/mg of microvessel protein and a 52 ± 13% increase in luminal GLUT1 in hypoglycemic animals, suggesting that both increased GLUT1 synthesis and a redistribution to favor luminal transporters account for the enhanced uptake. A corresponding (twofold) increase in cortical GLUT1 mRNA was observed by in situ hybridization. In contrast, no significant changes were observed in regional brain glucose uptake PA, total microvessel 55-kDa GLUT1, or luminal GLUT1 concentrations in hyperglycemic rats. There was, however, a 30-40% increase in total cortical GLUT1 mRNA expression, with a 96% increase in the microvessels. Neither condition altered the levels of GLUT3 mRNA or protein expression. These results show that hypoglycemia, but not hyperglycemia, alters glucose transport activity at the BBB and that these changes in transport activity result from both an overall increase in total BBB GLUT1 and an increased transporter concentration at the luminal surface.     

Radial microornament in spiriferid brachiopods and paleogeographical implications

Capillae are a major feature of the fine ornamentation in spiriferid brachiopods. Within the lower Devonian spiriferids, studied in this paper, two categories of organization can be distinguished: strictly radial orientation of the microstructures, which leads to the eospiriferid-type of organization, and pseudoradial orientation, which provides a delthyridid-type. Apart from this distinction, it can now be shown that the mode of development is quite different in each case. Thus, and allowing for differences in size, the capillae of eospiriferids are quite similar to the costae of costate spiriferids. On the other hand, the origin of the capillae is more complex in the delthyridids and as yet not fully known. Other factors (such as the rate of growth, the divergence angle of the capillae, etc.) have effects on the growth mechanisms and contribute to the existence of a large variety of microornaments. Furthermore. available data indicate that the divergence of the capillae is closely related to the paleogeographical distribution of the populations involved. If this observation proves valuable for the whole stock of spiriferids ( s.l. ), it opens new ground for paleozoogeographical investigations. □ Spiriferid brachiopods, eospiriferids, delthyridids. microornament, Devonian, paleogeography.     

Abnormal serum concentrations of proteins in Parkinson’s disease

Blood serum was used to identify protein biomarkers for diagnosis of Parkinson’s disease (PD) using analytically validated quantitative 2D-gel electrophoresis, and single variable and multivariate statistics. Using banked samples from a first medical center, we identified 57 specific protein spot biomarkers with disease-specific abnormal levels in serum of patients with PD, Alzheimer’s disease, amyotrophic lateral sclerosis and similar neurodegenerative conditions (337 samples), when compared to age-matched normal controls (132 samples). To further assess their clinical usefulness in Parkinson’s disease, we obtained prospective newly drawn blood serum samples from a second (56 PD, 30 controls) and third (6 PD, 48 controls) medical center. The protein concentrations of the 57 biomarkers were assessed by 2D-gel electrophoresis. Stepwise linear discriminant analysis selected a combination of 21 of the 57 as optimal to distinguish PD patients from controls. When applied to the samples from the second site, the 21 proteins had sensitivity of 93.3% (52 of 56 PD correctly classified), specificity of 92.9% (28 of 30 controls correctly classified); 15 of 15 patients with mild, 28 of 30 with moderate to severe symptoms, and all of the 6 PD patients from the third site were correctly classified. Eleven of the 21 proteins showed statistically significant abnormal concentrations in patients with mild symptoms, and 14 in patients with moderate-severe symptoms. The protein identities reflect the heterogeneity of Parkinson’s disease, and thus may provide the capability of monitoring the blood for a diverse range of PD pathophysiological mechanisms: cellular degeneration, oxidative stress, inflammation, and transport.     

Contamination affects the performance of insecticidal baits against German cockroaches (Dictyoptera: Blattellidae)

The effects of contamination of insecticidal bait formulations, by using mint oil and silica aerogel, were evaluated in a series of laboratory experiments against the German cockroach, Blattella germanica (L.). Bait consumption at 3 d for uncontaminated baits ranged from 0.01 g for Avert dust to 0.399 g for Combat dry bait with hydramethylnon presented in a station. LT50 values for uncontaminated gel bait deposits ranged from 0.4 d for PreEmpt containing imidacloprid to 4.1 d for Maxforce containing hydramethylnon. As a group, significantly more gel bait was consumed than solid formulations even when both formulations had similar concentrations of the same active ingredient. As a result, gel baits were significantly more toxic than solid formulations. Application of mint oil directly to bait deposits significantly decreased bait consumption and increased overall LT50 values. When bait formulation types were examined individually, there was no difference in consumption or toxicity between contaminated and uncontaminated gel formulations. Contaminated solid baits, however, had significantly greater LT50 values and less consumption than uncontaminated solid baits. Gel formulations probably absorbed the contaminants and removed them from the surface of the bait deposits resulting in normal bait consumption and toxicity. Gel and solid bait deposits, inside plastic exposure stations or alone with no station and placed onto mint oil-contaminated substrates, had significantly lower bait consumption and greater LT50 values than baits placed on uncontaminated substrates. Contamination of a baited area is more likely than contamination of just the bait deposit and therefore a more realistic test of the effects of contamination on bait performance. The importance of contamination to the performance of cockroach baits is discussed.     

The molecular scanner: concept and developments

Approaches aimed at deciphering the proteome have illustrated the need for relatively complex and highly sensitive methodologies. The major elements of proteome analysis, such as powerful protein separation and enzymatic processing, mass spectrometry and dedicated bioinformatics have been assembled in the development of the molecular scanner. This highly flexible and data-rich approach has combined the power of electrophoretic protein separation, the simultaneous digestion and transfer of proteins through an enzymatic membrane, the immediate use of the MALDI mass spectrometer to scan a collecting membrane, and the development of dedicated bioinformatics tools to perform protein identification and molecular imaging of the proteome. Clinical applications of the molecular scanner have also started to be developed for disease diagnosis in biological material.     

Cyclic carbon dioxide release in the dampwood termite, Zootermopsis nevadensis (Hagen)

Real-time traces of CO(2) release of pseudergates of the dampwood termite, Zootermopsis nevadensis (Hagen) were obtained using flow-through respirometry. Traces were made at each of six temperatures, between 10 and 35 degrees C. Termites released CO(2) in a cyclic pattern at each of the six temperatures. CO(2) release rate (as V(CO(2)) in ml h(-1)) increased significantly with temperature and body mass. Rate of change in V(CO(2)) with temperature (or Q(10)) was 2.11. Degree of cycling in CO(2) traces was estimable using the coefficient of variability. Coefficient of variability for both acyclic and cyclic traces declined exponentially with increasing temperature.     

Discontinuous gas exchange patterns of beet armyworm pupae, Spodoptera exigua (Lepidoptera: Noctuidae): effects of Bacillus thuringiensis Cry1C toxin, pupal age and temperature

Abstract. Changes in the discontinuous gas exchange cycle of pupal beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), exposed or not to Cry1C Bacillus thuringiensis toxin, are examined against developmental age (1–7 days) and at different temperatures (10–25 °C) using flow through respirometry. Both exposed and nonexposed pupae exhibit discontinuous gas exchange, but only at 10 °C; the frequency of cyclic release of CO₂ increases with increasing temperatures. The three phases of the discontinuous gas exchange cycle are distinct for both treatment groups. However, the duration of each phase is significantly greater for pupae exposed previously to toxin. The closed phase is 40 ± 14% longer, the flutter phase 23 ± 19% longer, and the open phase is 28 ± 12% longer when pupae were exposed to toxin. Respiratory water loss is 4.5 ± 1.3% for toxin exposed pupae and 2.1 ± 2.4% for unexposed pupae. Furthermore, the exposed pupae have significantly greater cuticular permeability (26.01 ± 1.9 µg cm⁻² h⁻¹ mmHg⁻¹) than the nonexposed pupae (9.64 ± 0.9 µg cm⁻² h⁻¹ mmHg⁻¹). However, in both strains, cuticular transpiration (>93%) far exceeds respiratory transpiration. Overall, total water loss is significantly greater in pupae whose larvae are exposed to toxin compared with pupae from nontreated larvae. Toxin exposed pupae have a mean cycle duration of 60 ± 2.5 min whereas that of nonexposed pupae is 42 ± 1.8 min.(ml g⁻¹ h⁻¹) of the open phase is greater earlier in pupal life followed by a minimum at mid-pupal stage and an increase at late-pupal development in both treatment groups. Combining all 7 days, closed, flutter and open phase (ml g⁻¹ h⁻¹), pupae exposed to toxin produce significantly more CO₂ during each phase. On average, toxin exposed pupae produce 52 ± 12, 43 ± 10 and 15 ± 37% more CO₂ than the untreated pupae during the closed, flutter and open phases, respectively. Therefore, the present study reinforces the need to use insects of similar developmental age in studies of insect respiration patterns and energy metabolism.     

Influences on tocopherol biosynthesis in the cyanobacterium Synechocystis sp. PCC 6803

To elucidate influences on the tocopherol biosynthesis in cyanobacteria, wild type and mutant cells of a putative methyltransferase in tocopherol and plastoquinone biosynthesis of Synechocystis sp. PCC 6803 were grown under different conditions. The vitamin E content of cells grown under different light regimes, photomixotrophic or photoautotrophic conditions and varying carbon dioxide supplies were compared by HPLC measurements. The tocopherol levels in wild type cells increased under higher light conditions and low carbon dioxide supply. Photomixotrophic growth led to lower vitamin E amounts in the cells compared to those grown photoautotrophically. We were able to segregate a homozygous deltasll0418 mutant under photoautotrophic conditions. In contrast to former suggestions in the literature the deletion of this gene is not lethal under photomixotrophic conditions and the influence on tocopherol and plastoquinone amounts is diminutive. The methyltransferase encoded by the gene sll0418 is not essential either for tocopherol or plastoquinone synthesis.