Citrate synthase and pyruvate kinase activities during early life stages of the shrimp Farfantepenaeus paulensis (Crustacea,Decapoda, Penaeidae): effects of development and temperature

Energy metabolism in early life stages of the shrimp Farfantepenaeus paulensis subjected to temperature reduction (26 and 20 °C) was determined using the activities of citrate synthase (CS) and pyruvate kinase (PK). At both temperatures, weight-specific activity of CS decreased throughout the ontogenetic development from protozoea II (PZ II) to postlarva XII–XIV (PL XII–XIV). PK activity reached a pronounced peak in PL V–VI, followed by a further decrease in PL XII–XIV. Temperature reduction produced variation in oxygen consumption rates (QO₂), ammonia–N excretion and in enzyme activities. Ammonia–N excretion was higher at 20 °C in mysis III (M III), PL V–VI and PL XII–XIV, resulting in substantially lower O:N ratios in these stages. QO₂ was increased in protozoea II (PZ II) and mysis I (M I) at 26 °C, while no difference in QO₂ was detected in the subsequent stages at either temperature. This fact coincided with higher CS and PK activities in M III, PL V–VI and PL XII–XIV at 20 °C compared with 26 °C. Regressions between individual enzyme activities and dry weight exhibited slope values of 0.85–0.92 for CS and 1.1–1.2 for PK and temperature reduction was reflected by higher slope values at 20 than at 26 °C for both enzymes. Weight-specific CS activity was positively correlated with QO₂ at 20 and 26 °C, and may thus be used as an indicator of aerobic metabolic rate throughout the early stages of F. paulensis. The variation in enzyme activities is discussed in relation to possible metabolic adaptations during specific ontogenetic events of the F. paulensis life cycle. Here, the catalytic efficiency of energy-metabolism enzymes was reflected in ontogenetic shifts in behaviour such as larval settlement and the adoption of a benthic existence in early postlarvae. In most cases, enhanced enzyme activities appeared to counteract negative effects of reduced temperature.     

Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos,used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera,Simuliidae) on the associated entomofauna,Paraty, state of Rio de Janeiro,Brazil

The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.     

Reproductive system abnormalities in Schistosoma mansoni adult worms isolated from Nectomys squamipes (Muridae: Sigmodontinae): brightfield and confocal laser scanning microscopy analysis

Schistosoma mansoni adult worms with genital anomalies isolated from Nectomys squamipes (Muridae: Sigmodontinae) were studied by confocal laser scanning microscopy under the reflected mode. One male without testicular lobes (testicular agenesia/anorchism) and two females, one with an atrophied ovary and another with 17 uterine eggs, were identified. The absence of testicular lobes occurred in a worm presenting otherwise normal male adult characteristics: tegument, tubercles and a gynaecophoric canal with spines. In both female specimens the digestive tube showed a vacuolated appearance, and the specimen with supernumerary uterine eggs exhibited a developing miracidium and an egg with a formed shell. The area of the ventral sucker was similar in both specimens however the tegument thickness, ovary and vitelline glands of the specimen with the atrophied ovary were smaller than those of the one with supernumerary eggs. These reported anomalies in the reproductive system call attention to the need to improve our understanding of genetic regulation and the possible role of environmental influences upon trematode development.     

Plant regeneration from callus cultures of <Emphasis Type="Italic">Maclura tinctoria</Emphasis>, an endangered woody species

Summary Some native species produce seeds with a low frequency of germination accompanied with a period of dormancy. These features make it difficult to produce new phenotypes through sexual propagation. Maclura tinctoria has been considered an endangered species due to extensive use of its wood and low frequency of seed germination. The objective of the present study is to establish an in vitro propagation system for this species. Organogenic friable callus formation from nodal segments has been obtained using woody plant medium (WPM) supplemented with 10.74 μM 1-naphthaleneacetic acid (NAA)+4.43 μM 6-benzylaminopurine (BA). Results indicate that the highest frequency of shoot formation is observed when WPM supplemented with 4.03 μM NAA+4.43 BA is used. For root formation, the use of WPM medium (pH adjusted to 7.0) supplemented with 23.62 μM indole-3-butyric acid (IBA) and 4.7gl⁻¹ activated charcoal is recommended. For acelimatization, subjecting rooted plantlets to 70%, 50%, and 30% mesh screen, each successively for a period of 7 d, has resulted in 97% plantlet survival.     

Isolation and characterization of a lectin from Annona muricata seeds

A lectin with a high affinity for glucose/mannose was isolated from Annona muricata seeds (Annonaceae) by gel filtration chromatography on Sephacryl S-200, ion exchange chromatography on a DEAE SP-5 PW column, and molecular exclusion on a Protein Pak Glass 300 SW column. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (PAGE) yielded two protein bands of approximately 14 kDa and 22 kDa. However, only one band was seen in native PAGE. The Mr of the lectin estimated by fast-performance liquid chromatography-gel filtration on Superdex 75 was 22 kDa. The lectin was a glycoprotein with 8% carbohydrate (neutral sugar) and required divalent metal cations (Ca2+, Mg2+, and Mn2+) for full activity. Amino acid analysis revealed a large content of Glx, Gly, Phe, and Lys. The lectin agglutinated dog, chicken, horse, goose, and human erythrocytes and inhibited the growth of the fungi Fusarium oxysporum, Fusarium solani, and Colletotrichum musae.     

Effect of temperature and surfactant on the control release of microencapsulated dye in lecithin liposomes. I

The objective of our work has been the microencapsulation of dyes with lecithin from soybean, with the formation of liposomes, as a substitute for synthetic auxiliaries so as to improve the quality of the effluent. Current scenarios promote the disintegration and leakage of the liposomes, such as, changes in temperature, pH and the use of surfactants. Since dyeing process is a mix of all these parameters, we pretended to study each one separately. Rhodamine 6G fluorescence is known to be concentration quenched through the formation of non-fluorescent dimmers and, additionally, through the energy transfer from rhodamine monomer to these dimmers (Baptista ALF, Coutinho PJG, Real Oliveira MECD, Gomes JINR. Proceedings of 13th International Symposium of Surfactants, SIS 2000, Gainesville, USA, 2000). The temperature, the surfactant and pH induce a release of the encapsulated dye resulting in rhodamine dilution and consequently alterations in the dimerization/binding equilibrium. The experimental spectra indicate that rhodamine binds almost completely to liposomes. The decomposition of the rhodamine fluorescence spectra allowed us to determine the percentage of released dye during a simulated dyeing process, and allowed us to conclude that the dimerization process occurs mainly at the inner interfaces. The amount of dye released induced by temperature changes was greater in the presence of surfactant.     

Chemical constituents from the infusion of Zollernia ilicifolia Vog. and comparison with Maytenus species

The new flavonoid glycoside kaempferol-3-O-alpha-L-rhamnopyranosyl(1-->2)-O-[alpha-L-rhamnopyranosyl(1-->6)]-O-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside was isolated together with (S)-zierin from the leaves of Zollernia ilicifolia (Fabaceae), a medicinal plant used as analgesic and antiulcerogenic effects in Brazilian Tropical Atlantic Rain Forest. The structures were established on the basis of 1H, 13C NMR and 2D NMR (COSY, HMBC, HMQC), UV, MS and IV spectra. The infusion of Zollernia ilicifolia was qualitatively compared to the infusion of the espinheiras-santas (Maytenus aquifolium and Maytenus ilicifolia) by HPLC-DAD.     

Simultaneous production of high activities of thermostable endoglucanase and β-glucosidase by the wild thermophilic fungus Thermoascus aurantiacus

The culture-medium composition was optimised, on a shake-flask scale, for simultaneous production of high activities of endoglucanase and β-glucosidase by Thermoascus aurantiacus using statistical factorial designs. The optimised medium containing 40.2 g l⁻¹ Solka Floc as the carbon source and 9 g l⁻¹ soymeal as the organic nitrogen source yielded 1130 nkat ml⁻¹ endoglucanase and 116 nkat ml⁻¹β-glucosidase activities after 264 h as shake cultures. In addition, good levels of β-xylanase (3479 nkat ml⁻¹) and low levels of filter-paper cellulase, β-xylosidase, α-l-arabinofuranosidase, β-mannanase, β-mannosidase, α-galactosidase and β-galactosidase were detected. Batch fermentation in a 5-l laboratory fermentor using the optimised medium allowed the production of 940 nkat ml⁻¹ endoglucanase and 102 nkat ml⁻¹β-glucosidase in 192 h. Endoglucanase and β-glucosidase showed optimum activity at pH 4.5 and pH 5, respectively, and they displayed optimum activity at 75 °C. Endoglucanase and β-glucosidase showed good stability at pH values 4–8 and 4–7, respectively, after a prolonged incubation (48 h at 50 °C). Endoglucanase had half-lives of 98 h at 70 °C and 4.1 h at 75 °C, while β-glucosidase had half-lives of 23.5 h at 70 °C and 1.7 h at 75 °C. Alkali-treated bagasse, steam-treated wheat straw, Solka floc and Sigmacell 50 were 66, 48.5, 33.5 and 14.4% hydrolysed by a crude enzyme complex of T. aurantiacus in 50 h. Received: 12 November 1999 / Accepted: 14 November 1999     

Structure and proteoglycan composition of specialized regions of the elastic tendon of the chicken wing

The elastic tendon of the avian wing has been described by others as a unique structure with elastic properties due to the predominance of elastic fibers in the midsubstance. Further analyses of the tendon have shown it to possess five anatomically distinct regions. Besides the major elastic region, a distally located fibrocartilage and three tendinous regions are present. The tendinous regions connect: (1) the muscle to the elastic region, (2) the elastic region to the fibrocartilage and (3) the latter to the insertion site. The elastic region possesses thick and abundant elastic fibers and very thin, interconnecting collagen fibers. The collagen fibers in the sesamoid fibrocartilage are thick and interwoven, defining spaces occupied by fibrochondrocytes embedded in a non-fibrillar and highly metachromatic matrix. Biochemical analyses have shown that the fibrocartilage has about tenfold the amount of glycosaminoglycans (GAGs) found in the other regions. The main GAG in this region was chondroitin sulfate (CS) (plus keratan sulfate as detected immunocytochemically), while the other regions showed variable amounts of CS, dermatan sulfate (DS) and heparan sulfate. Further analyses have shown that a large CS-bearing proteoglycan is found in the fibrocartilage. The elastic region possesses two main proteoglycans, a large CS-bearing proteoglycan (which reacted with an antibody against keratan sulfate after chondroitinase ABC treatment) and a predominant DS-bearing proteoglycan, which showed immunoreactivity when assayed with an anti-biglycan antibody. The results demonstrate that the elastic tendon is a complex structure with complex regional structural and compositional adaptations, suited to different biomechanical roles.     

Simultaneous detection of different glycosidase activities by 19F NMR spectroscopy

A fast method for the simultaneous detection of different glycosidolytic activities in commercially available enzyme preparations and crude culture filtrates was found in using, as substrate, a mixture of different glycosyl fluorides and 19F NMR spectroscopy as a screening technique. Accompanying studies regarding the hydrolytic stability of these fluorides in various buffer systems, as well as conditions of their long-term storage, were carried out. A simple procedure for the preparation of beta-D-mannopyranosyl fluoride in gram quantities is given.