Effect of impeller type on cellular morphology and production of clavulanic acid by Streptomyces clavuligerus.

It is essential to evaluate the effects of operating conditions in submerged cultures of filamentous microorganisms. In particular, the impeller type influences the flow pattern, power consumption, and energy dissipation, leading to differences in the hydrodynamic environment that affect the morphology of the microorganism. This work investigated the effect of different impeller types, namely the Rushton turbine (RT-RT) and Elephant Ear impellers in up-pumping (EEUP) and down-pumping (EEDP) modes, on cellular morphology and clavulanic acid (CA) production by Streptomyces clavuligerus in a stirred-tank bioreactor. At 800 rpm and 0.5 vvm, the cultivations performed using RT-RT and EEUP impellers provided higher shear conditions and oxygen transfer rates than those observed with EEDP. These conditions resulted in higher clavulanic acid production using RT-RT (380.7 mg/L) and EEUP (453.3 mg/L) impellers, compared to EEDP (196.6 mg/L). Although the maximum CA concentration exhibited the same order of magnitude for RT-RT and EEUP impellers, the latter presented 40% of the specific power consumption (4.9 kW/m3) compared to the classical RT-RT (12.0 kW/m3). The specific energy for CA production ( E CA ), defined as the energy cost to produce 1 mg of CA, was 3.5 times lower using the EEUP impeller (1.91 kJ/mgCA) when compared to RT-RT (5.91 kJ/mgCA). Besides, the specific energy for O2 transfer ( E O 2 ), the energy required to transfer 1 mmol of O2, was 2.3 times lower comparing the EEUP impeller (3.28 kJ/mmolO2) to RT-RT (7.65 kJ/mmolO2). The results demonstrated the importance of choosing the most suitable impeller configuration in conventional bioreactors to manufacture bioproducts.

Colitis caused by Clostridioides difficile infection in a domestic dog: A case report.

Clostridioides difficile has been identified as one of the primary etiologic agents of nosocomial diarrhea and pseudomembranous colitis in humans and other mammals associated following broad-spectrum antibiotics use. In Rio de Janeiro, Brazil we describe a case of C. difficile infection (CDI) in a 13-year-old male dog.

Application of Acid and Cold Stresses to Enhance the Production of Clavulanic Acid by Streptomyces clavuligerus.

Clavulanic acid (CA) is frequently prescribed for treatment of bacterial infections. Despite the large number of studies concerning CA production, there is still a need to search for more effective and productive processes because it is mainly produced by biochemical route and is chemically unstable. This paper evaluates the influence of acid and cold stresses on CA production by Streptomyces clavuligerus in bench scale stirred tank bioreactor. Four batch cultures were conducted at constant pH (6.8 or 6.3) and temperature (30, 25, or 20 °C) and five batch cultures were performed with application of acid stress (pH reduction from 6.8 to 6.3), cold stress (reduction from 30 to 20 °C), or both. The highest maximum CA concentration (684.4 mg L-1) was obtained in the culture conducted at constant temperature of 20 °C. However, the culture under acid stress, in which the pH was reduced from 6.8 to 6.3 at a rate of 0.1 pH unit every 6 h, provided the most promising result, exhibiting a global yield coefficient of CA relative to cell formation (YCA/X) of 851.1 mgCA gX-1. High YCA/X values indicate that a small number of cells are able to produce a large amount of antibiotic with formation of smaller amounts of side byproducts. This could be especially attractive for decreasing the complexity and cost of the downstream processing, enhancing CA production.

Gastroprotective activity of Cenostigma macrophyllum Tul. var. acuminata Teles Freire leaves on experimental ulcer models.

ETHNOPHARMACOLOGICAL RELEVANCE: Cenostigma macrophyllum Tul. var. acuminata Teles Freire (Leguminosae-Caesalpinioideae), popularly known in Brazil as "caneleiro", is widely used in folk medicine against gastrointestinal diseases. In previous studies, the ethanol extract of leaves from Cenostigma macrophyllum Tul. var. acuminata Teles Freire had shown antinociceptive, anti-inflammatory, antibacterial, antioxidant and antiulcerogenic activities. AIM OF THE STUDY: The aim of this study was to assess the gastroprotective effect of the hydroalcoholic fraction of leaves of Cenostigma macrophyllum Tul. var. acuminata Teles Freire (Cm-FHA), as well as to elucidate the possible underlying mechanisms of action. MATERIALS AND METHODS: Mice were used for the evaluation of the acute toxicity, and mice and rats to study the gastroprotective activity. The potential gastroprotective of Cm-FHA was assessed on different gastric ulcer models in rodents, such as absolute ethanol, HCl/ethanol, ischemia-reperfusion, cold restraint stress and indomethacin. The participation of prostaglandins, NO-synthase pathway and ATP-sensitive potassium channels (KATP) in gastroprotective activity of Cm-FHA were evaluated after treatment with a cyclooxygenase inhibitor (indomethacin), a NO-synthase inhibitor (L-NAME) and a KATP channel blocker (glibenclamide 5mg/kg), respectively. Likewise, the catalase activity was determinated in order to assess the possible participation of antioxidant mechanisms. RESULTS: No signs of acute toxicity was observed after oral acute administration of Cm-FHA, considering the analyzed parameters. Likewise, Cm-FHA promoted a protective effect against gastric ulcers induced by absolute ethanol (lesion inhibition by 40% at both 100 and 200mg/kg), HCl/ethanol (lesion inhibition by 50 or 48% at 100 or 200mg/kg, respectively), ischemia-reperfusion (lesion inhibition by 49 or 90% at 100 or 200mg/kg, respectively) and cold restraint stress (lesion inhibition by 63 or 76% at 100 or 200mg/kg, respectively), as well as a increase of catalase activity was observed. Otherwise, Cm-FHA was not able to protect gastric mucosa against indomethacin-induced lesions. Nitric oxide release, the of KATP channels opening and antioxidant activity are the possibly involved in the Cm-FHA-induced gastroprotective activity. CONCLUSION: This study corroborates the folk medicine use of Cenostigma macrophyllum for treatment of gastric ulcers, as well as reinforces this species as a valuable source of promising natural drugs with gastroprotective activity.

Efeito do gel da babosa (Aloe barbadensis Mill. ) associado ao ultrassom em processo inflamatório agudo / Effect of aloe (Aloe barbadensis Mill. ) gel combined with ultrasound in the acute inflammatory process

O presente trabalho teve por objetivo analisar a ação antiinflamatória do gel da Babosa a 2 por cento (Aloe barbadensis Mill.) associado ao Ultrassom pulsátil no modelo de edema de pata. Foram utilizados 25 ratos Wistar, (200-250 g), divididos em 5 grupos de 5 animais cada. Grupo1 (controle): ratos tratados com solução salina a 0,9 por cento; Grupo 2: ratos tratados topicamente com gel de A. barbadensis Mill. a 2 por cento; Grupo 3: animais tratados com Ultrassom; Grupo 4: ratos tratados com gel de A. barbadensis Mill. a 2 por cento associado ao Ultrassom; Grupo 5 (controle positivo): ratos tratados com Indometacina na dose de 5 mg Kg-1. Os animais dos grupos 1 e 5 receberam os respectivos tratamentos por via intra-peritoneal 30 minutos antes da injeção intra-plantar de carragenina e os grupos 2, 3 e 4 foram tratados por aplicação tópica de gel de A. barbadensis Mill. a 2 por cento, Ultrassom pulsátil e gel de A. barbadensis Mill. associado ao Ultrassom respectivamente 15 minutos após a indução do edema. Os animais do grupo 04 demonstraram redução significativa do edema quando comparados ao grupo controle, ao mesmo tempo, que se mostrou comparável à indometacina. Observou-se que o gel de aloe associado à fonoforose é capaz reduzir a formação do edema de pata em ratos.

This work aimed to evaluate the anti-inflammatory action of 2 percent aloe (Aloe barbadensis Mill.) gel combined with pulsed ultrasound in the paw edema model. Twenty-five Wistar rats (200-250 g) were divided into 5 groups of 5 animals each. Group1 (control): rats treated with 0.9 percent saline; Group 2: rats topically treated with 2 percent aloe gel; Group 3: rats treated with ultrasound; Group 4: rats treated with 2 percent aloe gel combined with ultrasound; Group 5 (positive control): rats treated with indomethacin at 5 mg Kg-1. Animals of groups 1 and 5 were intraperitoneally treated 30 min before intraplantar carrageenan injection and groups 2, 3 and 4 were treated by topical application of 2 percent aloe gel, pulsed ultrasound and aloe gel combined with ultrasound, respectively, 15 min after edema induction. Animals of group 4 had a significant reduction in edema relative to controls and showed to be comparable to indomethacin. Aloe gel combined with phonophoresis is capable of reducing paw edema formation in rats.

Rotifers of the upper Paraná River floodplain: additions to the checklist.

Rotifers present a high diversity in freshwater ecosystems. This study registered 11 genera and 42 species, new records for the Upper Paraná River floodplain. These results showed an increase in rotifer diversity in this ecosystem from 184 to 230 species. Among them some were registered only in the rivers and others in the lagoons. Thirty-seven species occurred in the littoral zone and 34 species in the pelagic; 3 species were registered only in the former zone and 2 species only in the latter. The lagoons presented the greatest richness, probably because of the greater stability, low current velocity, and the extensive aquatic macrophyte banks in the littoral zone of these environments as compared to those of the rivers. The highest number of species in the littoral habitats occurred due to the greater influence of shoreline vegetation, which allows greater habitat diversification. This fact contributed to the occurrence of non-planktonic species in the zooplankton samples.

Rotifers of the upper Paraná River floodplain: additions to the checklist

Rotifers present a high diversity in freshwater ecosystems. This study registered 11 genera and 42 species, new records for the Upper Paraná River floodplain. These results showed an increase in rotifer diversity in this ecosystem from 184 to 230 species. Among them some were registered only in the rivers and others in the lagoons. Thirty-seven species occurred in the littoral zone and 34 species in the pelagic; 3 species were registered only in the former zone and 2 species only in the latter. The lagoons presented the greatest richness, probably because of the greater stability, low current velocity, and the extensive aquatic macrophyte banks in the littoral zone of these environments as compared to those of the rivers. The highest number of species in the littoral habitats occurred due to the greater influence of shoreline vegetation, which allows greater habitat diversification. This fact contributed to the occurrence of non-planktonic species in the zooplankton samples

Malnutrition during lactation as a metabolic imprinting factor inducing the feeding pattern of offspring rats when adults. The role of insulin and leptin.

The aim of the present study was to determine the impact of malnutrition during early postnatal life and the feeding pattern of rat offspring when adults (2 months and 1 year old). In comparison with rats normally fed during lactation, we observed that adult offspring displayed a faster process of feeding reduction when a protein-free diet was offered. In addition, we studied the concentration of insulin and leptin in the lactating pups (10 days) and when these offspring became adult after the onset of a new feeding pattern induced by the protein-free diet. When the diet was changed at 60 days, the offspring malnourished during lactation displayed, after 3 days, a food intake reduction around 41.4 vs 14.2% of the control group. At 10 days of life, plasma leptin and insulin were higher in the malnourished pups when compared with normally fed rats (leptin: 4.6 +/- 0.8 vs 2.25 ng/ml; insulin: 0.73 +/- 0.12 vs 0.22 +/- 0.03 ng/ml) while at 60 days they showed reduction of both hormones when compared with the control group (leptin: 1.03 +/- 0.25 vs 1.43 +/- 0.5 ng/ml; insulin: 0.54 +/- 0.3 vs 0.61 +/- 0.4 ng/ml). Despite the different food intake reductions, the malnourished and control rats displayed a similar reduction of insulin and leptin after 3 days of protein-free diet (from 60 to 63 days). The data suggest that the high concentration of insulin and leptin found at 10 days in the malnourished pups may elicit a sustained long-term and unique feeding pattern.

Malnutrition during lactation as a metabolic imprinting factor inducing the feeding pattern of offspring rats when adults. The role of insulin and leptin

The aim of the present study was to determine the impact of malnutrition during early postnatal life and the feeding pattern of rat offspring when adults (2 months and 1 year old). In comparison with rats normally fed during lactation, we observed that adult offspring displayed a faster process of feeding reduction when a protein-free diet was offered. In addition, we studied the concentration of insulin and leptin in the lactating pups (10 days) and when these offspring became adult after the onset of a new feeding pattern induced by the protein-free diet. When the diet was changed at 60 days, the offspring malnourished during lactation displayed, after 3 days, a food intake reduction around 41.4 vs 14.2 percent of the control group. At 10 days of life, plasma leptin and insulin were higher in the malnourished pups when compared with normally fed rats (leptin: 4.6 0.8 vs 2.25 ng/ml; insulin: 0.73 0.12 vs 0.22 0.03 ng/ml) while at 60 days they showed reduction of both hormones when compared with the control group (leptin: 1.03 0.25 vs 1.43 0.5 ng/ml; insulin: 0.54 0.3 vs 0.61 0.4 ng/ml). Despite the different food intake reductions, the malnourished and control rats displayed a similar reduction of insulin and leptin after 3 days of protein-free diet (from 60 to 63 days). The data suggest that the high concentration of insulin and leptin found at 10 days in the malnourished pups may elicit a sustained long-term and unique feeding pattern

An Arabidopsis gene induced by wounding functionally homologous to flavoprotein oxidoreductases.

The regulation of genes in response to wounding is mediated in part by the octadecanoids 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA) and its methyl ester methyl jasmonate (MeJA). We identified, by differential display, an Arabidopsis gene (OPR3) induced after wounding. OPR3 is homologous to members of the flavin mononucleotide (FMN) binding proteins, including the old yellow enzyme (OYE) from yeast and 12-oxophytodienoate-10,11-reductase (OPR) from Arabidopsis. Transcripts of OPR3 rapidly accumulated in leaves after wounding and MeJA treatment, but they were detected in various tissues of unwounded plants at relatively low levels. Expression of the OPR3 gene was significantly reduced in wounded leaves of the coil mutant, indicating partial dependence on jasmonate perception for full induction of the gene. The recombinant protein of OPR3 cross-reacted with an antiserum raised against the OYE protein, and showed oxidation of beta-NADPH when OPDA or 15-deoxy-delta(12,14) prostaglandin J2 (PGJ2), an analogue of OPDA, was used as substrate. Beta-NADPH oxidation was not observed when MeJA, which lacks the double bond in the ketone ring, was used as substrate. The recombinant OPR3 protein also showed beta-NADPH oxidation activity in the presence of cyclohexenone, but not cyclohexanone, suggesting that the enzyme has specificity to cleavage of olefinic bonds in cyclic enones. The results show that the OPR3 gene product represents a new OPR of Arabidopsis induced after wounding.

Differential expression of a novel gene in response to coronatine, methyl jasmonate, and wounding in the Coi1 mutant of Arabidopsis.

Coronatine is a phytotoxin produced by some plant-pathogenic bacteria. It has been shown that coronatine mimics the action of methyl jasmonate (MeJA) in plants. MeJA is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. In Arabidopsis thaliana, MeJA is essential for pollen grain development. The coi1 (for coronatine-insensitive) mutant of Arabidopsis, which is insensitive to coronatine and MeJA, produces sterile male flowers and shows an altered response to wounding. When the differential display technique was used, a message that was rapidly induced by coronatine in wild-type plants but not in coi1 was identified and the corresponding cDNA was cloned. The coronatine-induced gene ATHCOR1 (for A. thaliana coronatine-induced) is expressed in seedlings, mature leaves, flowers, and siliques but was not detected in roots. The expression of this gene was dramatically reduced in coi1 plants, indicating that COI1 affects its expression. ATHCOR1 was rapidly induced by MeJA and wounding in wild-type plants. The sequence of ATHCOR1 shows no strong homology to known proteins. However, the predicted polypeptide contains a conserved amino acid sequence present in several bacterial, animal, and plant hydrolases and includes a potential ATP/GTP-binding-site motif (P-loop).