Continuous limonin degradation by immobilizedRhodococcus fascians cells in K-carrageenan

Limonin can be effectively degraded byRhodococcus fascians cells. These bacteria can be entraped in -carrageenan, and used in a continuous stirred tank reactor to degrade limonin in a continuous process. The effects of temperature limonin concentration, dilution rate, and aeration on the reactor behaviour have been tested, and the results correlated with changes in limonin conversion, substrate degradation rate, and free and immobilized biomass. Results showed that the immobilized cells were able to debitter limonin-containing media and the immobilized biomass was quite stable throughout the operational conditions tested. A population of free biomass was present in the reactor, the quantity of which was dependent on dilution rate. The immobilized bacteria increased its limonin-degrading capability when the substrate concentration was increased. The aeration was not strictly necessary for limonin degradation. Additionally, the immobilized cells were active and stable for more than 2 months of continuous operation, and were able to recover their limonin-degrading capability when used intermittently. Finally, none of the main components of a juice was noticeably altered during limonin degradation, so the reactor response was good enough to consider its application.     

Ontogeny of some endocrine cells of the digestive tract in sea bass (Dicentrarchus labrax): An immunocytochemical study

Serotonin- and ten peptide-immunoreactive (IR) cell types were identified in the digestive tract of sea bass (Dicentrarchus labrax L.) larvae of four morphofunctional phases ranging in age from hatching to 61 days. The sequence of appearance and location of endocrine cells during ontogenetic development of the larvae was determined. The differentiation of endocrine cells followed a distal-proximal gradient in the gut which paralleled the morphofunctional differentiation. Serotonin-IR cells were identified in the last portion of the digestive tract from phase I onwards and in the gastric region from phase III, before these regions were morphofunctionally differentiated; met-enkephalin-IR cells were identified from phase II onwards in both the differentiated rectum and the undifferentiated intestine; cholecystokinin (CCK)- and synthetic human gastrin-34-IR cells were located only in the intestine and first found in the undifferentiated intestine of phase II; human gastrin-17-, peptide YY (PYY)- and neuropeptide Y (NPY)-IR cells appeared in the intestine from phase II and in stomach in phase IV, when it showed gastric glands; pancreatic polypeptide (PP)- and glucagon-IR cells were observed in both intestine and stomach, but insulin- and somatostatin-IR cells only in stomach, from phase III, during which the intestine but not the stomach was differentiated. PP- and PYY-, PP- and glucagon-, and PYY- and glucagon-like immunoreactivities coexisted from their first appearance in some cells of the gut.     

Observations on the reproductive biology of two parasites ofHylesinus varius andPhloeotribus scarabaeoides (Col: Scolytidae): Cheiropachus quadrum (Hym: Pteromalidae) andDendrosoter protuberans (Hym: Braconidae)

Observations on the biology ofCheiropachus quadrum (Hym: Pteromalidae) andDendrosoter protuberans (Hym: Braconidae), were conducted. Both species are the main parasites of the olive bark beetlesHylesinus varius andPhloeotribus scarabaeoides (Col: Scolytidae) in the South of Spain. Results have shown that an increase in body size of the host does not imply an increase in parasite efficiency. In fact, host size inversely affects parasite efficiency forC. quadrum. Bearing in mind this fact, the abundance of the host and the ease of its rearing in the lab, it is therefore advisable to useP. scarabaeoides as the host for mass rearing of the parasites studied here. On the other hand, the presence of white light is a negative factor for parasite longevity and fecundity. The pupae and all larval instars are parasitised.C. quadrum does not have a preference for any particular stage or larval instar of the host whilst there is a preference for the third and fifth larval instar byD. protuberans. With respect to the sex ratio of parasites, an increase in the number of males increases the fecundity of the females. The results obtained in this study can be considered essential in the development of a biological control system for olive bark beetle pests based on an increase in the population ofC. quadrum andD. protuberans.     

Review on the sublethal effects of pure and formulated glyphosate on bees: Emphasis on social bees

Bees are declining worldwide, and the use of pesticides has been linked to this problem. Studies show that even herbicides can negatively impact bees, causing death or compromising health. As a result, concern about the use of glyphosate (GLY) has increased, as it is the most sold pesticide. Studies have shown that exposure of bees to GLY can trigger sublethal effects. Considering the speed with which information is published, reviews become important for the integration of knowledge, aiding understanding of the topic. Therefore, the present study aimed to review the literature on the sublethal effects of GLY and the different commercial formulations on bees. After the literary review, it was observed that the exposition, acute and chronic, of larvae and adults of social and solitary bees, to GLY and its formulations, can trigger alterations in gene expression, enzyme functioning, oxidative metabolism, cell/tissue structure, intestinal microbiota diversity, learning, food consumption, flight and vertical displacement capacity, circadian cycle and body development of these insects. The most used species in the studies was Apis mellifera L. Studies are still necessary to understand the sublethal effects of GLY on bees, in the medium and long term, on colony homeostasis, especially about the information on the toxicity of some surfactants present in the different commercial formulations.     

Three new Ecuadorian species of Axinaea (Melastomataceae)

Three new Ecuadorian species of Axinaea (Melastomataceae) are described: Axinaea flava, A. glauca, and A.lawessonii. All three species are endemic to southern Ecuador. Axinaea flava and A.glauca grow in the transition zone between montane forest and pbramo. They share characters such as shrubby habit, dense to moderate pubescence and coriaceous, rigid, erect leaves, which may be related to their high altitude habitat. Axinaea flava is the only species of the genus with a yellow corolla. Axinaea glauca, a shrub less than 1 m high, is the smallest Axinaea species known. Field observations show that these two species have a restricted habitat and their known populations are small, probably less than 100 individuals. The third species, A.lawessonii, grows in wet montane forests. It can grow as a shrub or a slender tree and its leaves are glabrous and less rigid than those of A.flava and A.glauca, characters which are probably a consequence of the more humid and benign habitat. Axinaea lawessonii is the only species of the genus in which the leaf margins have uncinate teeth. The species is rather frequent in southern Ecuador and has been collected in a dozen localities, most of which are within the Podocarpus National Park.     

Effect of water-miscible aprotic solvents on kyotorphin synthesis catalyzed by immobilized α-chymotrypsin

Summary Immobilized -chymotrypsin was used as catalyst to synthesize a kyotorphin derivative (Bz-Tyr-Arg-OEt) in the presence of five water-miscible aprotic solvents (dimethylsulphoxide, dimethylformamide, acetonitrile, acetone and tetrahydrofurane) at 30 °C. By using a kinetically-controlled approach, the maximum synthetic activity was obtained when Arg-OEt was used as nucleophile donor at a concentration 1.5-times higher than the acyl-acceptor substrate (Bz-Tyr-OEt). The water-miscible aprotic solvents enhanced greatly the synthetic activity proportionally to their hidrophilicity properties adequately measured by the log P parameter. At the optimum solvent concentration for the enzymatic peptide synthesis, both the water activity (Aw) of the media and the water content of the immobilized derivative showed a saturation profile against the log P parameter. As a function of the solvent hydrophilicity, these water parameters were shown as key parameters for the increase in the synthetic activity of the enzyme by the presence of these solvents.     

Treating tumor-bearing mice with vitamin D3 diminishes tumor-induced myelopoiesis and associated immunosuppression,and reduces tumor metastasis and recurrence

Metastatic Lewis lung carcinoma (LLC-LN7) tumors that secrete granulocyte/macrophage-colonystimulating factor (GM-CSF) stimulate myelopoiesis and induce bone marrow-derived immunosuppressor cells that are homologous to granulocyte/macrophage progenitor cells. In vitro treatment of the LLC-LN7 cells with 1,25-dihydroxyvitamin D₃ reduced tumor cell production of suppressor-inducing activity, although suppressor-inducing activity could be restored by reconstituting the tumor supernatants with recombinant GM-CSF. Treatment of mice having LLC-LN7 tumors with vitamin D₃ reduced tumor production of GM-CSF and the frequency of myeloid progenitor cells. This was associated with a reduction in immunosuppressor activity and an increase in T cell function. Vitamin D₃ treatment of mice having palpable tumors transiently retarded tumor growth, but caused a prominent reduction in tumor metastasis. Treating mice with vitamin D₃ after tumor excision resulted in a reduction in the tumor-induced myelopoietic stimulation and associated immunosuppressive activity, and enhanced T cell function. These mice had a markedly reduced incidence of tumor recurrence. The results of this study suggest that vitamin D₃ treatment of mice with GM-CSF-secreting tumors can interrupt the myelopoiesis-associated immunosuppressor cascade and, in turn, reduce tumor metastasis and recurrence.This study was supported in part by grants from the Medical Research Service of the Department of Veterans Affairs and by grants CA-45080 and CA-48080 from the National Institutes of Health     

Effect of 7-methylguanosine-5′-phosphate on the translation of rat milk-protein mRNAs in the wheat-germ cell-free system

The translation of polyadenylated and of non-poly-adenylated RNA obtained from lactating rat mammary gland was almost totally inhibited by 0,5 mM 7-methylguanosine-5-phosphate in the wheat-germ cell-free system, This inhibition was maintained during the preparation of the 9S whey-protein mRNA and of the 12S and ISS casein mRNAs, Chemical decapping of these mRNAs caused a similar reduction of their activity . Although a large fraction of milk-protein mRNAs have been reported to lack 3-polyadenylation, these results show that the mRNAs in the mammary gland do contain a 5-terminal 7-methylguanosine cap.