Gustavo Ferreira Martins

Bio: Gustavo Ferreira Martins is an academic researcher from Universidade Federal de Viçosa. The author has contributed to research in topics: Aedes aegypti & Midgut. The author has an hindex of 24, co-authored 106 publications receiving 1719 citations. Previous affiliations of Gustavo Ferreira Martins include University of the Azores & Oswaldo Cruz Foundation.

Post-embryonic development of the Malpighian tubules in Apis mellifera (Hymenoptera) workers: morphology, remodeling, apoptosis, and cell proliferation

Abstract: The honeybee Apis mellifera has ecological and economic importance; however, it experiences a population decline, perhaps due to exposure to toxic compounds, which are excreted by Malpighian tubules. During metamorphosis of A. mellifera, the Malpighian tubules degenerate and are formed de novo. The objective of this work was to verify the cellular events of the Malpighian tubule renewal in the metamorphosis, which are the gradual steps of cell remodeling, determining different cell types and their roles in the excretory activity in A. mellifera. Immunofluorescence and ultrastructural analyses showed that the cells of the larval Malpighian tubules degenerate by apoptosis and autophagy, and the new Malpighian tubules are formed by cell proliferation. The ultrastructure of the cells in the Malpighian tubules suggest that cellular remodeling only occurs from dark-brown-eyed pupae, indicating the onset of excretion activity in pupal Malpighian tubules. In adult forager workers, two cell types occur in the Malpighian tubules, one with ultrastructural features (abundance of mitochondria, vacuoles, microvilli, and narrow basal labyrinth) for primary urine production and another cell type with dilated basal labyrinth, long microvilli, and absence of spherocrystals, which suggest a role in primary urine re-absorpotion. This study suggests that during the metamorphosis, Malpighian tubules are non-functional until the light-brown-eyed pupae, indicating that A. mellifera may be more vulnerable to toxic compounds at early pupal stages. In addition, cell ultrastructure suggests that the Malpighian tubules may be functional from dark-brown-eyed pupae and acquire greater complexity in the forager worker bee.

Age-mediated and environmentally mediated brain and behavior plasticity in the stingless bee Melipona quadrifasciata anthidioides

Abstract: Structural changes in the insect brain related to age and individual experience may underlie the behavioral plasticity that is particularly important in such social insects as bees. This study assessed the influence of age and rearing conditions (field vs laboratory) in mediating changes in the volume of mushroom bodies and antennal lobes in the brains of workers of the native stingless bee Melipona quadrifasciata anthidioides Lepeletier, a pollinator species with small colonies exhibiting high level of sociability and behavioral versatility. Although only age-dependent enlargement was observed in the antennal lobes, significant increase (21 %) in the neuropils of the mushroom bodies occurred before the foraging age, in contrast to honeybees, and environmental complexity led to a significant increase in both the mushroom body volume and the walking activity. Such differences in the stingless bee M. quadrifasciata anthidioides as compared with the honeybee may assist in relating brain evolution and plasticity with the behavior in these social insects.

Morphological and morphometric studies of the antennal sensilla from two populations of Atta robusta (Borgmeier 1939) (Hymenoptera: Formicidae)

Abstract: The ant Atta robusta is endemic to the “restinga” ecosystems where it has an important role in the dynamics of seed dispersal. Despite its importance, A. robusta is considered a threatened species. In this study we analyzed the antennal sensory organs of two different populations of A. robusta (from the cities of Sao Mateus and Marica in in Espirito Santo and Rio de Janeiro States, respectively) using a scanning electron microscope (SEM). SEM revealed different types of sensilla in the A. robusta antennae, i.e., curved and straight trichoid, basiconic, ampullacea and coeloconic, which were highly abundant found in the distal flagellomeres (F) compared with other antenna regions. There were differences in samples collected from two locations in terms of the sensilla number and length. The average numbers of straight and curved trichoid sensillae numbers were different in F9 and F8, respectively, while the average length of the curved trichoid sensilla was only different in F9. These variations in sensory organs between two populations of A. robusta may indicate an adaptation of this species to different environmental conditions. The number of straight trichoid sensilla was only significantly different in F9.

Insights Into the Proteome of the Spermatheca of the Leaf-Cutting Ant Atta sexdens rubropilosa (Hymenoptera: Formicidae)

Abstract: Summary Fifteen of the 22 differentially expressed proteins in the spermathecae of virgin and inseminated females of the leaf cutting ant Atta sexdens rubropilosa were tentatively identified. The profile of expressed proteins of the spermatheca differed significantly between virgin and fertilized females. Data from this study should contribute to the elucidation of the roles of these various proteins in prolonged storage and maintenance of viable spermatozoa within the female.

Mammalian caspases: structure ,a ctivation ,s ubstrates, and functions during apoptosis

Abstract: ■ Abstract Apoptosis is a genetically programmed, morphologically distinct form of cell death that can be triggered by a variety of physiological and pathological stimuli. Studies performed over the past 10 years have demonstrated that proteases play critical roles in initiation and execution of this process. The caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases. Caspases are synthesized as relatively inactive zymogens that become activated by scaffold-mediated transactivation or by cleavage via upstream proteases in an intracellular cascade. Regulation of caspase activation and activity occurs at several different levels: ( a) Zymogen gene transcription is regulated; ( b) antiapoptotic members of the Bcl-2 family and other cellular polypeptides block proximity-induced activation of certain procaspases; and ( c) certain cellular inhibitor of apoptosis proteins (cIAPs) can bind to and inhibit active caspases. Once activated, caspases cleave a variety of intracellular polypeptides, including major structural elements of the cytoplasm and nucleus, components of the DNA repair machinery, and a number of protein kinases. Collectively, these scissions disrupt survival pathways and disassemble important architectural components of the cell, contributing to the stereotypic morphological and biochemical changes that characterize apoptotic cell death.

Principles of Insect Morphology

Abstract: THE author of this book ranks as the foremost American worker on insect morphology. His contributions on the subject are notable for their clarity and originality of thought, and the appearance of a volume, embodying his ideas in comprehensive form, is sure of a hearty welcome. In its preparation, Mr. Snodgrass has incorporated the results of much first-hand study with those of many recent investigators in the same field. He has produced an outstanding book wherein knowledge of facts is combined with that of function and, at the same time, theoretical conceptions of the origins and relationships of organs and parts are not overlooked. Principles of Insect Morphology By R. E. Snodgrass. (McGraw-Hill Publications in the Zoological Sciences.) Pp. ix + 667. (New York and London: McGraw-Hill Book Co., Inc., 1935.) 36s. net.

Effects of neonicotinoids and fipronil on non-target invertebrates

Abstract: We assessed the state of knowledge regarding the effects of large-scale pollution with neonicotinoid insecticides and fipronil on non-target invertebrate species of terrestrial, freshwater and marine environments. A large section of the assessment is dedicated to the state of knowledge on sublethal effects on honeybees (Apis mellifera) because this important pollinator is the most studied non-target invertebrate species. Lepidoptera (butterflies and moths), Lumbricidae (earthworms), Apoidae sensu lato (bumblebees, solitary bees) and the section “other invertebrates” review available studies on the other terrestrial species. The sections on freshwater and marine species are rather short as little is known so far about the impact of neonicotinoid insecticides and fipronil on the diverse invertebrate fauna of these widely exposed habitats. For terrestrial and aquatic invertebrate species, the known effects of neonicotinoid pesticides and fipronil are described ranging from organismal toxicology and behavioural effects to population-level effects. For earthworms, freshwater and marine species, the relation of findings to regulatory risk assessment is described. Neonicotinoid insecticides exhibit very high toxicity to a wide range of invertebrates, particularly insects, and field-realistic exposure is likely to result in both lethal and a broad range of important sublethal impacts. There is a major knowledge gap regarding impacts on the grand majority of invertebrates, many of which perform essential roles enabling healthy ecosystem functioning. The data on the few non-target species on which field tests have been performed are limited by major flaws in the outdated test protocols. Despite large knowledge gaps and uncertainties, enough knowledge exists to conclude that existing levels of pollution with neonicotinoids and fipronil resulting from presently authorized uses frequently exceed the lowest observed adverse effect concentrations and are thus likely to have large-scale and wide ranging negative biological and ecological impacts on a wide range of non-target invertebrates in terrestrial, aquatic, marine and benthic habitats.

Pesticide-Induced Stress in Arthropod Pests for Optimized Integrated Pest Management Programs

Abstract: More than six decades after the onset of wide-scale commercial use of synthetic pesticides and more than fifty years after Rachel Carson's Silent Spring, pesticides, particularly insecticides, arguably remain the most influential pest management tool around the globe. Nevertheless, pesticide use is still a controversial issue and is at the regulatory forefront in most countries. The older generation of insecticide groups has been largely replaced by a plethora of novel molecules that exhibit improved human and environmental safety profiles. However, the use of such compounds is guided by their short-term efficacy; the indirect and subtler effects on their target species, namely arthropod pest species, have been neglected. Curiously, comprehensive risk assessments have increasingly explored effects on nontarget species, contrasting with the majority of efforts focused on the target arthropod pest species. The present review mitigates this shortcoming by hierarchically exploring within an ecotoxicology fram...