Technetium-99m-labeled ceftizoxime loaded long-circulating and pH-sensitive liposomes used to identify osteomyelitis

Osteomyelitis is an infectious disease located in the bone or bone marrow. Long-circulating and pH-sensitive liposomes containing a technetium-99m-labeled antibiotic, ceftizoxime, (SpHL-(99m)Tc-CF) were developed to identify osteomyelitis foci. Biodistribution studies and scintigraphic images of bone infection or non infection-bearing rats that had been treated with these liposomes were performed. A high accumulation in infectious foci and high values in the target-non target ratio could be observed. These results indicate the potential of SpHL-(99m)Tc-CF as a potential agent for the diagnosis of bone infections.     

Effect of water renewal on dominance hierarchy of juvenile Nile tilapia

Nile tilapia social position (Oreochromis niloticus) can be mediated by multiple channels, including chemical communication. Absence of chemical cues in the environment prevents hierarchical settlement among pairs, and enhances time spent in confrontations. The aim of this study was to test the effect of continuously renewed water flow on the establishment of hierarchical dominance in Nile tilapia juveniles. In this condition, a high frequency of attacks and disruption on hierarchical stability were expected because chemical cues for hierarchy maintenance could be washed out. After 3 days in isolation, the fish were paired by standard size but not by sex, and submitted to two conditions: continuously renewed water flow (RENEWED, n = 7) and non-renewed water flow (NONRENEWED, n = 8). The paired fish were placed in an aquarium (40 cm × 30 cm × 40 cm) for 3 h; four 10-min sessions were video-recorded: the first, immediately after the fish were paired and the others 1, 2, and 3 h after pairing. Hierarchy was identified by a dominance index (DI = given attacks/received + given attacks) for each fish. The hierarchical stability was achieved by analyzing the difference between dominant DI and subordinate DI (DI-D). Hierarchy was established in both groups after second session because the DI was significantly higher for one fish of the pair. The frequency of attacks of the dominant fish in RENEWED and NONRENEWED conditions was similar in all observation sessions. The attack frequency by subordinate fish was also similar during the first three sessions (2-h pairing). However, the frequency of attacks by subordinate fish in the RENEWED condition was higher than in the NONRENEWED situation at the fourth observation session (means ± S.E.: RENEWED = 2.83 ± 0.94 × 10 min⁻¹ and NONRENEWED = 0.25 ± 0.16 × 10 min⁻¹; Mann–Whitney, p = 0.04). At this point, a significant reduction of the DI-D was observed (means ± S.E.: RENEWED = 0.70 ± 0.11 and NONRENEWED = 1,00 ± 0.002; Mann–Whitney, p = 0.04). The changes in DI-D were related to more frequent attacks by the subordinated fish in renewed water flow. According to our results, the unsteady agonistic interaction under renewed water flow leads to social instability. Thus, continuous water renewing can wash out relevant chemical substances and therefore disturb the dominance recognition by subordinate fish.     

Phenology of mating flight in Ecitoninae (Hymenoptera: Formicidae) in a Brazilian Atlantic Forest location

The mating flight of Ecitoninae ants was studied using four light traps inspected daily during the whole year of 2004. A total of 1285 males belonging to 15 species was collected, the species number varying monthly from two to 11. For most species, the beginning of the reproductive period occurred in November or in February. Synchronism of the flight activity among species was observed in the genera Neivamyrmex and Eciton, while segregation occurred in two Labidus species. In the model tested to explain male abundance over the year, including rainfall, temperature and interaction between both factors, only temperature was significant.     

ALS mutants of human superoxide dismutase form fibrous aggregates via framework destabilization

Many point mutations in human Cu,Zn superoxide dismutase (SOD) cause familial amyotrophic lateral sclerosis (FALS), a fatal neurodegenerative disorder in heterozygotes. Here we show that these mutations cluster in protein regions influencing architectural integrity. Furthermore, crystal structures of SOD wild-type and FALS mutant H43R proteins uncover resulting local framework defects. Characterizations of beta-barrel (H43R) and dimer interface (A4V) FALS mutants reveal reduced stability and drastically increased aggregation propensity. Moreover, electron and atomic force microscopy indicate that these defects promote the formation of filamentous aggregates. The filaments resemble those seen in neurons of FALS patients and bind both Congo red and thioflavin T, suggesting the presence of amyloid-like, stacked beta-sheet interactions. These results support free-cysteine-independent aggregation of FALS mutant SOD as an integral part of FALS pathology. They furthermore provide a molecular basis for the single FALS disease phenotype resulting from mutations of diverse side-chains throughout the protein: many FALS mutations reduce structural integrity, lowering the energy barrier for fibrous aggregation.     

Assessment of mite fauna in different coffee cropping systems in Brazil

Agro-ecological diversification may increase natural biodiversity and decrease environmental impacts caused by the intensification of management practices, especially with respect to pest control. This study aimed to evaluate mite populations from surveys in commercial coffee (Coffea arabica) orchards managed in different ways. Four different cropping systems were compared: a conventional system (CS), non-pesticide system (NPS), organic system (OS) and organic agroforestry system (OAS). Mite samples were taken from 24 coffee plantations (n?=?6 for each management strategy). Six leaves per plant were collected from five sampling sites totalling 30 leaves from each plantation. Mites were removed from individual leaves, counted and identified to family level. Amongst the predatory mites, two families were detected; the Phytoseiidae was the most abundant family while the Stigmaeidae, generalist predatory mites, were only found in two management systems (NPS and AOS). Of the two families of phytophagous mites, the family Tenuipalpidae was the most abundant, but rarely found in AOS. The other phytophagous family, Tetranychidae, was less abundant in coffee crops than Tenuipalpidae, but the most abundant phytophagous family in CS. Understanding the relationship between mite populations and management practices can aid in choice of spraying strategies for different coffee management systems.     

Control of Pratylenchus brachyurus in soybean with Trichoderma spp. and resistance inducers

Trichoderma spp. is a fungus with nematode control potential; however, its potential to control the root lesion nematode Pratylenchus brachyurus remains poorly studied. Thus, the aim of this study was to select Trichoderma spp. isolates and assess their ability to control P. brachyurus in soybean crops. Different experiments were conducted aiming at selecting isolates, assessing whether they were able to reduce nematode penetration in plants or cause mortality in vitro, and whether they were able to induce resistance in soybean, as well as at studying the possibility of using the selected isolates associated with resistance inducers (acibenzolar‐S‐methyl, Ecolife^? and AgroMos^?). The selection experiment found three isolates showing satisfactory results, namely GF422, GF425 and GF427; the GF362 isolate was assessed in the subsequent experiments. These four isolates reduced P. brachyurus penetration in soybean roots and promoted nematode mortality in vitro. Increased total protein and catalase activity were recorded, mainly in the 72‐hr assessments. Overall, the protein production was different between isolates. The best results were found in the combination between the GF362 isolate and the three resistance inducers, between GF427 and Ecolife^?, between GF427 and AgroMos^? and between GF422 and Ecolife^?.     

Description and identification of two new diseases of guariroba palm (Syagrus oleraceae) in Brazil

Guariroba is a palm species native to central Brazil. Seedlings of guariroba with leaf spots of unknown aetiology were found in Patos de Minas, Minas Gerais, Brazil. The leaf spots were manifest as two different symptom types: the first lesion type consisted of necrotic spots with a rounded to elongate shape, with a light colour and dark edges; the second lesion type had a rounded shape, was dark brown in colour with a light brown edge. The objective of this study was to elucidate the aetiology of both diseases. The likely causal agents were isolated and Koch's postulate fulfilled. Subsequently, the ITS region of rDNA from both micro‐organisms were amplified and sequenced. According to the morphological characteristics and molecular analyses, the fungal species were identified as Pestalotiopsis adusta (causing necrotic spots with a rounded to elongate shape, with a light colour and dark edges), and Alternaria tenuissima (causing lesions with a rounded shape, dark brown in colour with a light brown edge). Identification of the causal organisms of these two diseases will help guide management approaches that might be tested to reduce impact of the disease on Guariroba, including the use of fungicides and cultural approaches.     

Risks associated with introduction of poeciliids for control of mosquito larvae: first record of the non‐native Gambusia holbrooki in Argentina

This study confirms the presence of two species of the non‐native mosquitofish Gambusia in Argentina. The risks that they represent to native biota, their potential dispersal in the region, and their effectiveness in mosquito larvae control are discussed.