Sulfur fertilization increases defense metabolites and nitrogen but decreases plant resistance against a host-specific insect.

We tested the sulfur-modulated plant resistance hypothesis using potted cabbage (Brassica oleracea var. capitata) plants that were grown without and with increasing levels of sulfur fertilization. Changes in plant chemical traits were assessed and developmental performance of Plutella xylostella, a highly host-specific leaf-chewing insect, was followed. Leaf sulfur concentration gradually increased with growing addition of sulfur in soil; however, there was a generalized saturation response curve, with a plateau phase, for improvements in total leaf nitrogen, defense glucosinolates and insect performance. Plutella xylostella performed better in sulfur-fertilized cabbage probably because of the higher level of nitrogen, despite of the higher content of glucosinolates, which are toxic for many non-specialized insects. Despite the importance of sulfur in plant nutrition and production, especially for Brassica crops, our results showed that sulfur fertilization could decrease plant resistance against insects with high feeding specialization.

Cabbage Seasonal Leaf Quality Mediating the Diamondback Moth Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) Performance.

Seasonal variation in plant quality may be intense enough to generate predictable patterns in insect herbivore populations. In order to explain seasonal oscillations in neotropical populations of the diamondback moth Plutella xylostella (L.), we tested the following: (1) if nutritional quality of cabbage (Brassica oleraceae var. capitata), a primary host plant of diamondback moth, adversely affects the performance of this insect in late spring and early summer, when populations decline and go extinct, and (2) if nutritional features of cabbage change with the seasons. We measured the performance of diamondback moth reared on leaves of cabbages grown during the four seasons of the year. Summer plants proved to be worse for the survival of the immature stages and subsequent adult fecundity, but there were no significant differences between the remaining seasons. Our results support the hypothesis that short-lived plants, grown in different seasons of the year in the tropics, have different nutritional and defensive attributes. We analyzed nutritional quality of cabbage leaves from the four seasons, but only total lipids were reduced in summer plants. Neotropical populations of diamondback moth collapse before plant quality decay in the summer. If the diamondback moth is well adapted to the seasonal deterioration of the habitat, including the reduction in the quality of host plants, it is expected that emigration happens before the mortality increases and natality decreases during the summer.

Ciclooxygenase inhibitor and metronomic chemotherapy association for the treatment of metastatic anal sac carcinoma in dog: case report / Inibidor de ciclo-oxigenase associado à quimioterapia metronômica no tratamento de carcinoma de saco anal metastático canino: relato de caso

Metronomic chemotherapy consists of an anticancer modality treatment. It is applicable in patients at an advanced stage, with the objective of increasing overall survival. The aim of this study was to report an anal sac apocrine carcinoma case in a dog with lymph node metastasis treated with metronomic chemotherapy sequential to surgery and conventional chemotherapy using gemcitabine and carboplatin. Metronomic chemotherapy was associated with cyclooxygenase-2 (COX-2) inhibitors, due to strong tumor COX-2 immunohistochemistry expression. Metronomic chemotherapy was initiated with cyclophosphamide, but it was replaced by lomustine, also in metronomic dosage, due to adverse effects. Treatment showed effectiveness, since the patient's overall survival exceeded 1095 days (36 months), considerably higher than the mean overall survival expected for this pathology.(AU)

Quimioterapia metronômica consiste em uma modalidade de tratamento anticancerígeno, aplicável a pacientes em estadiamento avançado, com o objetivo de aumentar a sobrevida global. O objetivo deste trabalho foi relatar um caso de carcinoma apócrino do saco anal, em uma cadela, com metástase em linfonodo tratado com quimioterapia metronômica sequencial à cirurgia e quimioterapia convencional utilizando-se gencitabina e carboplatina. O tratamento metronômico foi associado ao uso de inibidores de ciclo-oxigenase-2 (COX-2), baseando-se na constatação de sua expressão tumoral. A terapia metronômica iniciou-se com ciclofosfamida, mas houve necessidade de substituição pela lomustina, também em dose metronômica, devido à ocorrência de efeitos adversos. O tratamento mostrou ser eficaz, pois a sobrevida do paciente ultrapassa 1095 dias (36 meses) desde a cirurgia, sendo consideravelmente maior que a média relatada para essa patologia.(AU)