Sensitivity of embryos and larvae of the freshwater prawn Macrobrachium borellii to the latest generation pesticide spirotetramat

The aim of this study was to evaluate the effects of the last generation insecticide spirotetramat (STM) on embryos and larvae of the freshwater prawn Macrobrachium borellii. Both embryos and larvae were exposed to serial dilutions of STM to determine the LC50 values. After 96-h of exposure, live larvae were fixed for histological analysis. In addition, ovigerous females were exposed to a sublethal concentration of STM (1.7 mg/L) for 96 h to evaluate the activity of the enzymes catalase, glutathione-S-transferase, and superoxide dismutase as well as the lipoperoxidation (LPO) and protein oxidation levels in embryos. The larvae showed a high sensitivity to STM evidenced by the LC50-96 h value (0.011 mg/L). On the contrary, the embryos were highly resistant to STM exposure, and no lethal effect was observed in the treatments with high concentrations of this insecticide (LC50-96 h > 150 mg/L). Among all the biochemical parameters evaluated in the embryos exposed to STM, only LPO showed a significant increase compared to controls. This was probably due to a restricted entry of the insecticide through the embryonic coat. Thus, a preliminary study of the structure and permeability of the embryonic coat was carried out in control embryos. The analysis by electron microscopy revealed that its structure is formed by four embryonic envelopes composed of multiple layers while the assay with a fluorescent probe revealed that the embryonic coat increases its permeability during development. STM caused significant histopathological alterations in the hepatopancreas and gills of larvae. This study showed that although the embryos of M. borellii could be protected by the embryonic coat, the larvae are very vulnerable to the STM toxicity. So, it is necessary to continue evaluating the effects of these new pesticides on non-target organisms, such as aquacultured species, to help predict their ecotoxicological risks derived from the increasing agricultural activity developed worldwide

Suscetibilidade de Trypanosoma evansi à anfotericina B Trypanosoma evansi susceptibility to amphotericin B

O objetivo deste estudo foi avaliar a suscetibilidade do Trypanosoma evansi in vitro e in vivo à anfotericina B. Nos testes in vitro, foram utilizadas quatro concentrações (0,06; 0,25; 1,0; 4,0µg mL-1) de anfotecicina B frente a uma suspensão de T. evansi em solução tampão fosfato rico em glicose (PBS - glicose). Para avaliar a eficácia in vivo, foram utilizados 15 ratos parasitados com T. evansi. Em dois grupos de cinco ratos infectados, doses únicas diárias de 1 (grupo A) e de 3mg kg-1 (grupo B) foram administradas via intraperitonial durante 10 dias, e a parasitemia foi avaliada por meio de esfregaço sanguíneo. Grupo C (n=5) foi utilizado como grupo controle positivo, infectados com T. evansi e não tratados, e o grupo D (n=5), como controle negativo. Os ensaios in vitro evidenciaram suscetibilidade de 100% do T. evansi à anfotericina B após 7h, em todas as concentrações avaliadas. Nos ratos, nem a maior dose testada curou os roedores, apesar de ter prolongado a vida destes em comparação à vida dos animais infectados, mas não tratados. Foi também investigada a função hepática e renal dos ratos após a terapia, e os parâmetros bioquímicos analisados mantiveram-se dentro da normalidade. Conclui-se que o T. evansi in vitro é suscetível à anfotericina B. A dose 3mg kg-1 testada aumentou a expectativa de vida de ratos infectados, porém não teve efeito curativo.<br>The aim of this study was to evaluate the Trypanosoma evansi susceptibility to amphotericin B in vitro and in vivo. Four concentrations (0.06, 0.25, 1.0, and 4.0µg mL-1) of amphotericin B were tested against a suspension containing T. evansi and phosphate buffer solution with glucose in the in vitro assay. Fifteen rats infected with T. evansi were used for the in vivo assay. Groups A (n=5) and B (n=5) received daily doses of 1 and 3mg kg-1 during 10 days and the parasitemia was estimated daily by microscopic examination of smears. The rats from group C (n=5) were the positive control and were infected but not treated. Rats from group D (n=5) were used as negative control. in vitro assays showed a 100% of susceptibility of T. evansi to amphotericin B after 7 hours, at all concentrations tested. The higher dose tested did not cure the rats, although treated rats had a longer life span in comparison to the non-treated group. Adverse effects on renal and hepatic hemodynamics were also researched. Biochemical parameters obtained were within the normal ranges. It was concluded that T. evansi is susceptible to amphotericin B in vitro. The dose of 3 mg kg-1 tested in rats increased life span, but did not cure the animals

Comparative analysis of the relative growth of Uca rapax (Smith) (Crustacea, Ocypodidae) from two mangroves in S\ue3o Paulo, Brazil

A study on the relative growth of two populations of Uca rapax (Smith, 1870) was performed primarily to determine the size at onset sexual maturity. The species was sampled monthly in Itamambuca (23º24'43"S and 45º00'73"W) and Ubatumirim (23º20'17.8"S and 44º53'2.2"W) mangroves. Carapace width (CW) and length (CL), abdomen width (AW), major cheliped propodus length (PL) and height (PH) for each sex, and gonopod length (GL) for males were measured with a calliper (0.01 mm). Allometric analyses were used to estimate size at maturity. The relationships that most precisely indicated the size at onset of sexual maturity were AW vs. CW, for females and PL vs. CW, for males. Males and females are mature, respectively at 15.2 and 12.1 mm CW in samples from Itamambuca and 13.5 and 11.2 mm CW in samples from Ubatumirim mangrove. Positive allometric growth of females abdominal width is likely related to the incubation process, while positively allometry growth of male's cheliped almost certainly relates to reproductive behaviour.<br>O estudo do crescimento relativo foi utilizado para determinar quais dimensões evidenciam melhor a maturidade sexual morfológica de Uca rapax (Smith, 1870). Os caranguejos foram coletados mensalmente nos manguezais de Itamambuca (23º24'43"S e 45º00'73"W) e Ubatumirim (23º20'17,8"S e 44º53'2,2"W), em período de maré baixa. Os caranguejos de ambos os sexos foram mensurados com um paquímetro (0,01 mm) quanto à largura da carapaça (LC), comprimento da carapaça (CC) e largura do abdome (LA). Nos machos mensurou-se ainda o comprimento e altura do própodo do quelípodo maior (CPQ e APQ) e comprimento do gonopódio (CG) e, no caso das fêmeas, comprimento e altura do própodo do quelípodo direito (CPQ e APQ). As análises alométricas foram utilizadas para estimar o tamanho da maturidade sexual morfológica. As relações que melhor evidenciaram o tamanho da maturidade foram LA vs. LC para fêmeas e CPQ vs. LC para machos. Machos e fêmeas estão maduros morfologicamente, respectivamente com 15,2 e 12,1 mm de LC em Itamambuca e 13,5 e 11,2 mm de LC no manguezal do rio Ubatumirim. O crescimento alomético positivo da largura do abdomen de fêmeas está relacionado com o processo de incubação, enquanto a alometria positiva do quelípodo dos machos pode estar relacionada ao comportamento reprodutivo

Maturidade sexual do caranguejo Armases rubripes (Rathbun) (Crustacea, Brachyura, Sesarmidae) na Baía de Sepetiba, Rio de Janeiro, Brasil Sexual maturity of the crab Armases rubripes (Rathbun) (Crustacea, Brachyura, Sesarmidae) in Sepetiba Bay, Rio de Janeiro, Brazil

Objetivou-se analisar a maturidade sexual de Armases rubripes (Rathbun, 1897) em três diferentes ambientes (rio, praia arenosa e manguezal) no sudeste do Brasil. Os caranguejos foram coletados mensalmente de julho/2002 a fevereiro/2004, utilizando-se peneiras no Rio Sahy durante as marés altas e, manualmente, na praia e no manguezal, durante as marés baixas. Os animais foram capturados por dois coletores num esforço de 15 minutos por estação de coleta. No laboratório, os exemplares foram separados por sexo e mensurados em relação a largura da carapaça, do abdome e comprimento do gonopódio. As gônadas, gonopódios e o abdome foram analisados segundo sua forma e seu aspecto. Um total de 4.051 indivíduos foram amostrados (1.067 machos, 1.563 fêmeas e 1.421 juvenis). Foram determinados cinco morfotipos: juvenis, machos imaturos, fêmeas imaturas, machos maduros e fêmeas maduras. O início da maturidade sexual fisiológica e morfológica ocorreu de forma assíncrona, com machos produzindo gametas mais cedo que as fêmeas. O tamanho da primeira maturidade sexual apresentou diferença significativa entre os ambientes analisados, exceção observada para o manguezal. Os indivíduos obtidos no manguezal apresentaram menores tamanhos para o início da maturidade sexual. Embora, estimados os tamanhos da maturidade sexual morfológica de machos e fêmeas, a análise do crescimento alométrico foi inadequado para a espécie.<br>The present study analyzed the sexual maturity of Armases rubripes (Rathbun, 1897) in three populations from different environmental conditions (river, beach and mangrove) in the southeastern Brazilian coast. Crabs were sampled monthly from July 2002 to February 2004; they were captured with sieves at Sahy River, during the high tides, and by hand at beach and mangrove areas, during low tides. Animals were captured by establishing a catch effort of two collectors during 15 minutes for each station. At laboratory, all individuals were sexed and the carapace width measured. The gonads, gonopods and abdomen morphology were observed according to shape and macroscopic aspects. A total of 4,051 specimens were sampled (1,067males, 1,563 females and 1,421 juveniles). There were recognized five morphotypes: juveniles, immature males, immature females, mature males and mature females. The onset of physiological and morphological sexual maturity was asynchronous within sexes, of which, males reaching the ability to produce gametes earlier than females. The size at the onset of sexual maturity was significantly different among populations different coming from areas, except for mangrove area. The individuals obtained from mangrove showed the shortest size at the onset of sexual maturity. Therefore, estimates of males and females sizes at morphological sexual maturity the allometric growth analyses are inadequate in this species