ACUTE TOXICITY and ENVIRONMENTAL RISK of OXYTETRACYLINE and FLORFENICOL ANTIBIOTICS TO PACU (Piaractus mesopotamicus)

The oxytetracyline (OTC) and florfenicol (FLO) are the most used antibiotics for bacterial disease control in fish. The aims are: estimating the lethal concentration 50% initial (LC(I) 50;48h) of OTC (Terramicina (R)) and FLO (Aquaflor (R)) for pacu (Piaractus mesopotamicus); classifying OTC and FLO according to the acute toxicity and the risk of environmental intoxication; and assessing OTC and FLO dilution effect in water quality variables. Fish were acclimatized for 10 days in a bioassay room at 27 +/- 2 degrees C. Then nine animals (three each concentration) were exposed to 7.0; 7.5; 8.0 or 8.5 mg L(-1) of OTC or to 600.0; 700.0; 800.0; 900.0 and 1000.0 mg L(-1) of FLO and a control treatment. The water quality variables recorded daily were: pH, temperature, electric conductivity, and dissolved oxygen. OTC and FLO were classified according to acute toxicity and environmental risk. The estimated OTC LC(I) 50;48h for pacu is 7.6 mg L(-1) and the estimated FLO is > 1000 mg L(-1). OTC reduced the dissolved oxygen concentration, and it was considered moderately toxic, causing risk of environmental intoxication to pacu. FLO is not toxic; it does not cause risk of environmental intoxication to pacu and does not change water quality variables.

Subconjunctival Delivery of Antibiotics in a Controlled-Release System A Novel Anti-infective Prophylaxis Approach for Cataract Surgery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Artificial oocyte activation using calcium ionophore in ICSI cycles with spermatozoa from different sources

The present study evaluated the effect of artificial oocyte activation (AOA) with calcium ionophore A23187 oil intracytoplasmic sperm injection (ICSI) cycles using spermatozoa from different sources. The 314 cycles evaluated were divided into three groups according to sperm origin, the ejaculated group (n = 92), the epididymal group (n = 82). and the testicular roup (n = 140). Each group was further split into experimental subgroups, depending oil whether or no AOA was performed. In additions the cycles of women younger than 36 years were evaluated separately. For each experimental group, ICSI outcomes were compared between subgroups. No significant difference was observed between subgroups for all sperm origin groups. When evaluating only the cycles of women younger than 36 years of age, AOA increased the percentage of high-quality embryos (74.5 versus 53.0%. P = 0.011) and the implantation rate (19.3 versus 10.5%, P = 0.0025) when it was used with ejaculated spermatozoa, and the percentage of high-quality embryos (64.4 versus 50.3%, P = 0.006) when epididymal spermatozoa were used. These results may suggest that both sperm maturity and oocyte quality play a role in oocyte activation. However. this study is to be continued to confirm these findings.

Artificial oocyte activation with calcium ionophore A23187 in intracytoplasmic sperm injection cycles using surgically retrieved spermatozoa

Objective: To evaluate the effect of artificial oocyte activation (AOA) on intracytoplasmic sperm injection (ICSI) cycles using surgically retrieved sperm.Design: Laboratory study.Setting: Fertility/assisted fertilization center.Patient(s): Couples undergoing surgical sperm retrieval for ICSI (n = 204).Intervention(s): Application of calcium ionophore A23187 for AOA.Main Outcome Measure(s): Cycles were divided into experimental groups according to the origin of the sperm used for injection and the type of azoospermia: [1] testicular sperm aspiration in nonobstructive-azoospermic patients (TESA-NOA group, n = 58), [2] TESA in obstructive-azoospermic patients (TESA-OA group, n = 48), [3] and percutaneous epididymal sperm aspiration in obstructive-azoospermic patients (PESA-OA, n = 98). For each experimental group, cycles where AOA was applied (subgroup: activation) were compared with cycles in which AOA was not applied (Subgroup: control). The fertilization, high-quality embryo, implantation, and pregnancy rates were compared among the subgroups.Result(s): For patients undergoing TESA, AOA did not improve ICSI outcomes for either type of azoospermia. However, for cases in which the injected sperm were retrieved from the epididymis, a statistically significantly increased rate of high-quality embryos was observed with AOA.Conclusion(s): Artificial oocyte activation may improve ICSI outcomes in azoospermic patients when epididymal, but not testicular spermatozoa, are injected. (Fertil Steril (R) 2009;92:131-6. (C)2009 by American Society for Reproductive Medicine.)

The effects of Brazilian and Bulgarian propolis in vitro against Salmonella Typhi and their synergism with antibiotics acting on the ribosome

Salmonella enterica serovar Typhi is the causative agent of typhoid fever in humans, and the use of antibiotics is essential for controlling this infection; however, the excessive use of antibiotics may select resistant strains. Propolis is a honeybee product and its antimicrobial activity has been intensively investigated. Thus, the objective of this study was to investigate a possible synergism between propolis (collected in Brazil and Bulgaria) and antibiotics acting on the ribosome (chloramphenicol, tetracycline and neomycin) against Salmonella Typhi in vitro. The synergism was investigated by using 1/2 and 1/4 of the minimum inhibitory concentration for propolis and these antimicrobial agents, evaluating the number of viable cells according to the incubation time. Brazilian propolis showed a bacteriostatic action against S. Typhi, while Bulgarian propolis showed a bactericidal activity and a synergistic effect with the three antibiotics. Variations in the biological assays might be due to the differences in their chemical compositions. Based on the results, one may conclude that Bulgarian propolis showed an important antibacterial action, as well as a synergistic effect with antibiotics acting on the ribosome, which points out a possible therapeutic strategy evaluating the use of propolis preparations for the treatment of Salmonella Typhi infection.

Antibacterial effects of Brazilian and Bulgarian propolis and synergistic effects with antibiotics acting on the bacterial DNA and folic acid

Propolis is a honeybee product that has been used since ancient times because of its therapeutic effects. It can be used in the development of alternative therapies for the treatment of many diseases, and because propolis shows antibacterial action, this work was carried out in order to investigate a possible synergism between propolis and antibiotics acting on DNA (ciprofloxacin and norfloxacin) and on the metabolism (cotrimoxazole) against Salmonella Typhi. Propolis samples collected in Brazil and Bulgaria were compared in these assays, and the synergism was investigated by using 1/2 and 1/4 of the minimal inhibitory concentration for propolis and antibiotics, evaluating the number of viable cells according to the incubation time. Brazilian and Bulgarian propolis showed antibacterial activity, but no synergistic effects with the three tested antibiotics were seen. Previous works by our laboratory have revealed that propolis has synergistic effects with antibiotics, acting on the bacterial wall and ribosome, but it does not seem to interact with antibiotics acting on DNA or folic acid, and only a bacteriostatic action was seen in these assay conditions.

Synergistic effect of propolis and antibiotics on the Salmonella Typhi

O objetivo do presente trabalho foi investigar um possível efeito sinérgico entre extrato alcoólico de própolis do Brasil e Bulgária com alguns antibióticos (Amoxilina, Ampicilina e Cefalexina) utilizados contra Salmonella Typhi. Própolis do Brasil e Bulgária mostraram uma atividade antibacteriana, embora a amostra da Bulgária tenha sido mais eficiente. Ambas as amostras apresentaram um efeito sinérgico com os antibióticos estudados. Pode-se concluir que as amostras de própolis possuem atividade antibacteriana, bem como apresentam efeito sinérgico com antibióticos utilizados contra Salmonella Typhi.

Penetration of zona-free hamster, bovine and equine oocytes by stallion and bull spermatozoa pretreated with equine follicular fluid, dilauroylphosphatidylcholine or calcium ionophore A23187

Experiments evaluated the ability of follicular fluid (FF), dilauroylphosphatidylcholine (PC12) and the calcium ionophore A23187 (A23187) to induce capacitation in stallion and bull spermatozoa, determined by the ability of the spermatozoa to penetrate zona-free hamster, bovine and equine oocytes. Spermatozoa suspensions were incubated at 37 degreesC in one of the following treatments: 1) a modified Tyrode's medium (BGM3) alone, 2) BGM3 + FF; 3) BGM3 + PC12; 4) BGM3 + FF + PC12; 5) BGM3 + A23187; and 6) BGM3 + FF + A23187. Treated spermatozoa were incubated with zona-free hamster, bovine and equine oocytes for 3 h, after which oocytes were stained to assess spermatozoa penetration. The number of hamster oocytes penetrated by spermatozoa incubated in BGM3 alone (1/30) or in presence of FF (2/31) was significantly lower (P < 0.05) than by spermatozoa treated with PC12 or A23187 (16/30 and 17/30, respectively). Processing stallion spermatozoa either by a swim-up procedure or by centrifugation through a Percoll gradient increased the percentages of motile spermatozoa in the final sample, and spermatozoa collected by both processes penetrated similar numbers of zona-free hamster oocytes (P > 0.05). Although treating spermatozoa with PC12 or A23187 enabled both stallion and bull spermatozoa to penetrate oocytes, higher numbers of bovine oocytes were penetrated by bull spermatozoa (25/30) than by stallion spermatozoa (4/30) regardless of spermatozoal treatment. However, the number of zona-free hamster and equine oocytes penetrated by bull spermatozoa (25/30 and 12/18 respectively) and stallion spermatozoa (17/30 and 15/21 respectively) were similar (P > 0.05). We conclude that both PC12 and A23187 capacitate stallion and bull spermatozoa sufficiently to permit the acrosome reaction to occur, enabling spermatozoa to penetrate homologous and heterologous zona-free oocytes. (C) 2001 by Elsevier B.V.

The antibiotics roseoflavin and 8-demethyl-8-amino-riboflavin from Streptomyces davawensis are metabolized by human flavokinase and human FAD synthetase

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cara inchada of cattle, an infectious, apparently soil antibiotics-dependant periodontitis in Brazil

O objetivo desta revisão das pesquisas sobre a cara inchada dos bovinos (CI), realizadas no decorrer dos últimos 30 anos, é de elucidar melhor a sua etiologia. A CI geralmente tem sido considerada de origem nutricional, causada primariamente por deficiência ou desequilíbrio mineral. A doença caracteriza-se por uma periodontite rapidamente progressiva, que afeta os tecidos peridentários a nível dos premolares e molares no período de erupção dos dentes e que se inicia geralmente em bezerros jovens. A doença causou grandes perdas econômicas aos pecuaristas da Região Centro-Oeste do Brasil, nas décadas de 1960 e 1970, com a ocupação de novas terras para criação de gado. O freqüente abaulamento lateral dos ossos maxilares nos bezerros, que deu à doença o nome popular de cara inchada, foi demonstrado ser conseqüente à periostite crônica ossificante resultante da alveolite purulenta da CI. Das lesões peridentárias foi isolado, em grande número, Bacteroides melaninogenicus, sempre junto com Actinomyces (Corynebacterium) pyogenes. Bactérias classificadas como pertencentes ao grupo sacarolí-tico e não-sacarolítico dos pigmentados de negro Bacteroides melaninogenicus e Bacteroides spp também foram isoladas, em pequeno número, de bovinos jovens sadios de fazendas CI-negativas. Ensaios in vitro mostraram que os antibióticos estreptomicina e actinomicina, bem como os sobrenadantes de cultivos de actinomicetos do solo de fazendas CI-positivas, aplicadas nas bactérias ensaiadas em concentrações subinibidoras, aumentaram significativamente (até 10 vezes) a aderência de B.melaninogenicus a células epiteliais da gengiva bovina. Esses antibióticos são produzidos no solo em conseqüência de um aumento do número de actinomicetos, incluindo os do gênero Streptomyces, quando há modificação de sua microbiota em áreas previamente ocupadas por mata virgem ou vegetação natural de Cerrado, que foram cultivadas pela primeira vez na formação de pastagem para o gado. em face da epidemiologia da CI, há fortes evidências de que a ingestão desses antibióticos pelos bovinos, junto com a forrageira, seja importante fator desencadeante para o desenvolvimento da periodontite. Através do aumento da aderência de B. melaninogenicus ao epitélio da gengiva marginal, em face da ingestão dos antibióticos pelos animais, as bactérias conseguem colonizar, formar a placa bacteriana e tornar-se patogênicas. Há evidência de que o fator desencadeante (aparentemente, os antibióticos) esteja também presente no leite de vacas-mães de bezerros afetados pela CI. Foi demonstrado que as bactérias envolvidas na periodontite produzem enzimas e endotoxinas capazes de ação destrutiva sobre os tecidos peridentários. A epidemiologia da CI, com a diminuição de sua incidência e o seu desaparecimento no decorrer dos anos, pode ser explicada pelo fato de que o prévio equílibrio da microbiota no solo virgem foi alcançado novamente e a produção dos antibióticos se reduziu. Desta maneira, a CI deve ser considerada como uma periodontite infecciosa multifatorial, causada sobretudo por bactérias anaeróbias pertencentes ao grupo Bacteroides melaninogenicus e, ao que tudo indica, desencadeada pela ingestão contínua, com a forrageira, de concentrações subinibidoras de antibióticos de solos recentememente cultivados. Esta hipótese é reforçada pela observação recente de novos surtos de CI, em áreas anteriormente positivas para a doença, em conseqüência da reforma de pastagens e capineiras após muitos anos. A natureza infecciosa da CI-periodontite foi confirmada através de experimento, em que virginiamicina mostrou-se eficaz no tratamento oral de bovinos afetados pela doença. Os antibióticos espiramicina e virginiamicina, usados como aditivos em suplementos minerais no campo, mostraram-se eficientes na prevenção da CI.

Sensitivity of ant (Cephalotes) colonies and individuals to antibiotics implies feeding symbiosis with gut microorganisms

Ants in the tribe Cephalotini are exceptional in that they maintain microorganisms in their digestive tract. To understand what these microorganisms mean to the ants, we observed the feeding habits of Cephalotes pusillus and Cephalotes atratus, finding that in nature they feed on extrafloral nectars, homopteran secretions, and bird droppings. Feeding the antibiotic kanamycin to colonies of C. pusillus in the laboratory kills them. Ants desiccate or starve rather than feed on liquids to which the antibiotics gentamycin and netilmycin have been added, but feed and survive on liquids containing nystatin, penicillin, and ampicillin. We identified over 10 microorganisms from the intestine of C. pusillus with different antibiotic-resistance patterns. The bacteria are from the genera Corynebacterium, Brevibacterium, Sphingobacterium, Ochrobactrum, Myroides, Brevundimonas, Alcaligenes, Stenotrophomonas, Moraxella, and Pseudomonas. We hypothesize that the microorganisms provide nutrients to the ants by synthesizing amino acids from carbohydrates and nitrates. We do not know whether the ants collect the bacteria from the environment, but they transmit them to their young. They culture them in their digestive tract, eventually feeding on them.