Heart mechanical and hemodynamic parameters of a beetle,Tenebrio molitor,at selected ages

The physiological processes that occur during the aging of insects are poorly understood. The aim of this study was to describe the changes in contractile activity and hemodynamic parameters of the heart that take place as the coleopteran beetle, Tenebrio molitor, ages. The frequency of heart contractions in beetles that had just undergone metamorphosis (median 24.7 beats/min) was significantly lower than the frequency of heart contractions in older beetles. In 56% of beetles that were < 1 week of age, a pattern of contractile activity with alternating periods of higher and lower contraction frequency was detected, suggesting that some posteclosion developmental processes occur during the first week of adulthood. All beetles that were 1 week of age showed a regular rhythm of heart contractions (median 72 beats/min). In older beetles, abnormalities such as heart arrhythmias or heart arrest were observed. The incidence of arrhythmia as well as the arrhythmicity index was highest in beetles that were 8–18 weeks old. The calculated stroke volume (SV) was also found to increase from eclosion to 12 weeks of age, and then decreased as adults aged further. Interestingly, cardiac output increased gradually, but the ejection fraction did not change significantly with age.     

Role of glutathione in apoptosis induced by radiation as determined by 1H MR spectra of cultured tumor cells

The relationship between apoptosis induced by gamma radiation and glutathione in cells of two human cancer cell lines, HeLa from cervix carcinoma and MCF-7 from mammary carcinoma, was examined. MCF-7 cells appeared to be more radioresistant than HeLa cells, and radiation-induced apoptosis, which was monitored by assessing phosphatidylserine externalization, was observed in HeLa cells but not in MCF-7 cells. Glutathione levels monitored by (1)H MRS were higher in MCF-7 cells than in HeLa cells, while the opposite was true for the free glu signals. MCF-7 cells became more radiosensitive when treated with 0.1 mM buthionine sulfoximine, which inhibits GSH synthesis through inactivation of gamma-glutamylcysteine synthetase, with the concomitant appearance of radiation-induced apoptosis. We can thus reasonably associate, at least in part, the resistance of MCF-7 cells to apoptosis with a high level of glutathione and probably with a high activity of gamma-glutamylcysteine synthetase. A late decrease in glutathione concentration after irradiation was observed in MCF-7 cells, but not in HeLa cells and to a lesser degree in buthionine sulfoximine-treated MCF-7 cells. This would indicate that the radiation-induced decrease in glutathione concentration is not related to the onset of apoptosis, but it is more likely related to glutathione consumption as a result of detoxification reactions.     

Cardioactive properties of Solanaceae plant extracts and pure glycoalkaloids on Zophobas atratus

Glycoalkaloids, the biologically active secondary metabolites produced by Solanaceae plants, are natural defenses against animals, insects and fungi. In this paper, the effects of glycoalkaloids present in extracts of Solanaceae plants (potato, tomato and black nightshade) or pure commercial glycoalkaloids on the coleopteran Zophobas atratus F. were evaluated by in vitro and in vivo bioassays using heart experimental models. Each tested extract induced a dose‐dependent cardioinhibitory effect. The perfusion of Zophobas atratus semi‐isolated heart using the highest potato and tomato extract concentration (1 mmol/L) caused irreversible cardiac arrests, while extract from black nightshade produced fast but reversible arrests. Pure commercial glycoalkaloids caused similar but less evident effects compared with extracts. Our results showed that the bioactivity of tested compounds depended on their structure and suggested the existence of synergistic interactions when combinations of the main glycoalkaloids of potato and black nightshade were used for trials. Surprisingly, injection of tomato and potato extracts in 1‐day‐old pupae of Zophobas atratus induced reversible positive chronotropic effects and decreased the duration of the both phases (anterograde and retrograde) of the heart contractile activity. Furthermore, these extracts affected the amplitude of the heart contractions.     

Alternative Ultrasound Gel for a Sustainable Ultrasound Program: Application of Human Centered Design

This paper describes design of a low cost, ultrasound gel from local products applying aspects of Human Centered Design methodology. A multidisciplinary team worked with clinicians who use ultrasound where commercial gel is cost prohibitive and scarce. The team followed the format outlined in the Ideo Took Kit. Research began by defining the challenge "how to create locally available alternative ultrasound gel for a low-resourced environment? The "End-Users," were identified as clinicians who use ultrasound in Democratic Republic of the Congo and Ethiopia. An expert group was identified and queried for possible alternatives to commercial gel. Responses included shampoo, oils, water and cornstarch. Cornstarch, while a reasonable solution, was either not available or too expensive. We then sought deeper knowledge of locally sources materials from local experts, market vendors, to develop a similar product. Suggested solutions gleaned from these interviews were collected and used to create ultrasound gel accounting for cost, image quality, manufacturing capability. Initial prototypes used cassava root flour from Great Lakes Region (DRC, Rwanda, Uganda, Tanzania) and West Africa, and bula from Ethiopia. Prototypes were tested in the field and resulting images evaluated by our user group. A final prototype was then selected. Cassava and bula at a 32 part water, 8 part flour and 4 part salt, heated, mixed then cooled was the product design of choice.     

Purification of S-2-hydroxyacylglutathione hydrolase (Glyoxalase II) from calf brain

S-2-Hydroxyacylglutathione hydrolase (Glyoxalase II) from calf brain has been purified 8333-times compared to 65,000 g supernatant of brain homogenate. The purification procedure employs Affi-Gel blue and preparative isoelectric focussing and offers a suitable method for the preparation of highly purified enzyme. Calf brain Glyoxalase II is a basic protein with a pl of 7.63 determined by isoelectric focusing. An evaluation of the relative molecular mass by gel filtration gave a value of about 23,000. During the purification procedure a constant Km value of about 0.325 mM was observed. A turnover number of 16,100 min-1 was calculated for the purified enzyme.     

Effect of gamma irradiation on membranes of normal and pathological erythrocytes (beta-thalassemia)

Summary The influence of ionizing radiation on the membrane of human normal erythrocytes has extensively been studied and a variety of effects including changes in the cation fluxes [3, 9] or in non-electrolytes permeability [5, 6, 11], in membrane fluidity, in peroxidation of unsaturated lipids as well as chemical composition or structural modifications [4, 7, 8] has been observed.However, only few studies deal with the effects of ionizing radiation on pathological red blood cells.In this work, we have investigated by means of electron spin resonance (ESR) spectroscopy the effects of⁶⁰Co-radiation on the normal and homozygous-thalassemic human erythrocyte membranes [2, 13].Presented in part at the VII Congress of the Società Italiana di Biofisica Pura ed Applicata Lipari (Italy) 1985     

Localization of the genes controlling B chromosome transmission rate in maize (Zea mays ssp. mays, Poaceae)

In previous papers we found that the frequency of B chromosomes in native races of maize varies considerably in different populations. Moreover, we found genotypes that control high and low transmission rates (TR) of B chromosomes in the Pisingallo race. In the present work crosses were made to determine whether the genes controlling B-TR are located on the normal chromosome set (As) or on the B chromosomes (Bs). We made female f.0B × male m.2B crosses between and within high (H) and low (L) B-TR groups. The Bs were transmitted on the male side in all cases. The mean B-TR from the progeny of f.0B (H) × m.2B (H) and f.0B (H) × m.2B (L) crosses was significantly higher than that from f.0B (L) × m.2B (L) and f.0B (L) × m.2B (H) crosses. The results show that the B-TR of the crosses corresponds to the H or L B-TR of the 0B female parents irrespective of the Bs of the male parent. This indicates that B-TR is genetically controlled by the 0B female parent and that these genes are located on the A chromosomes.     

New Proctolin Analogues: Synthesis and Biological Investigation in Insects

Summary We have extended our work on structure/activity relationship studies of the neuropeptiden proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH) by evaluating the effects of the following proctolin analogues: H-X¹-Tyr-Leu-Pro-Thr-OH, where X¹=d-Arg(I),N-Me-Arg (II), Can (III), Orn(di-Me) (IV), Orn (iPr) (V), Lys(N, N-di-Me) (VI), Lys(iPr) (VII), Lys(Nic) (VIII) andd-Lys(Nic) (IX). In analogues I–IX, the N-terminal Arg residue was replaced by basic amino acid derivatives with peptides containing amino acid residues with an isosteric system on the back side chain relative to Arg (compounds III, V and VI) orhomo-Arg (compound VII). Analogues I–IX were evaluated for myotropic activity on thein vitro heart preparation ofTenebrio molitor, whereas peptides II, V, and VII–IX were tested for contractile activity on the isolated foregut of locustSchistocerca gregaria. Peptide II and III showed full cardiotropic activity inT. molitor while peptides V and VII showed 40% and 15%, respectively, locust-gut contracting activity of proctolin.     

Comparison of melibiose utilizing baker's yeast strains produced by genetic engineering and classical breeding

Yeast strains currently used in the baking industry cannot fully utilize the trisaccharide raffinose found in beet molasses due to the absence of melibiase (alpha-galactosidase) activity. To overcome this deficiency, the MEL1 gene encoding melibiase enzyme was introduced into baker's yeast by both classical breeding and recombinant DNA technology. Both types of yeast strains were capable of vigorous fermentation in the presence of high levels of sucrose, making them suitable for the rapidly developing Asian markets where high levels of sugar are used in bread manufacture. Melibiase expression appeared to be dosage-dependent, with relatively low expression sufficient for complete melibiose utilization in a model fermentation system.     

The primary structure of the hypertrehalosemic neuropeptide from tenebrionid beetles: a novel member of the AKH/RPCH family

A hypertrehalosemic neuropeptide from the corpora cardiac of the two tenebrionid beetle species, Tenebrio molitor and Zophobas rugipes, was purified by high performance liquid chromatography, and its sequence determined by pulsed-liquid phase sequencing employing Edman degradation after deblocking enzymatically the N-terminal pyroglutamate residue. Additionally, the C-terminus of the peptide was blocked as shown by the lack of breakdown using carboxypeptidase. In both species an identical octapeptide, designated Tem-HrTH, with the following amino acid sequence, was found: pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2. This primary sequence has an 88% homology with the hypertrehalosemic hormone I (Pea-CAH-I) from the American cockroach as well as with the red pigment-concentrating hormone (RPCH) of prawns. Injection of the synthetic peptide into larvae or young adults of T. molitor or adult Z. rugipes increases the hemolymph carbohydrate levels in a dose-dependent manner. Thin layer chromatography identified the elevated sugar component of the hemolymph as the disaccharide trehalose. Carbohydrate release from larval fat body in vitro was also shown upon administration of a low concentration of synthetic Tem-HrTH.