A sorting platform determines the order of protein secretion in bacterial type III systems

Bacterial type III protein secretion systems deliver effector proteins into eukaryotic cells in order to modulate cellular processes. Central to the function of these protein-delivery machines is their ability to recognize and secrete substrates in a defined order. Here, we describe a mechanism by which a type III secretion system from the bacterial enteropathogen Salmonella enterica serovar Typhimurium can sort its substrates before secretion. This mechanism involves a cytoplasmic sorting platform that is sequentially loaded with the appropriate secreted proteins. The sequential loading of this platform, facilitated by customized chaperones, ensures the hierarchy in type III protein secretion. Given the presence of these machines in many important pathogens, these findings can serve as the bases for the development of novel antimicrobial strategies.     

The influence of method and frequency of irrigation on soil aeration and some biochemical responses of apple trees

Summary The effect of various irrigation regimes on soil aeration was tested in a two-year experiment with 15 year-old apple trees growing in soil containing 67% clay. Irrigation was applied by sprinklers at four intervals ranging from 3 to 18 days and by trickle irrigation every 7 days. Each treatment received a total of 800–850 mm water from May until September. Irrigation by sprinkling at 7 day intervals appeared to be optimal for fruit growth. Less frequent irrigations resulted in smaller fruits; sprinkling at 3–4 day intervals, as well as trickle irrigation reduced the fruit growth rate in July. Leaves from plots irrigated once every 3–4 days had a low chlorophyll content and accumulated relatively large amounts of ethanol, particularly when grafted on the Khashabi rootstock, which is highly susceptible to damage caused by inadequate soil aeration. With increasing intervals between irrigations, the resistance of the leaf surface to the diffusion of water vapour measured prior to irrigation increased, and water loss relative to that from an evaporation pan decreased. Sprinkling at intervals of 14 days resulted in maximal, and at 3–4 days in minimal, air contents of the soil when calculated as averages for the total period of irrigation. The decrease in soil air content with very frequent irrigations was particularly marked in the upper soil layer; this same layer also had a relatively low air content near the emitters in trickle irrigation. After each irrigation, relatively large amounts of ethylene accumulated in the soil atmosphere, indicating inadequate soil aeration, particularly with sprinkling intervals of 3–4 days and at a depth of 30 cm. However, the influence of the irrigation treatments on the oxygen and carbon dioxide contents of the soil atmosphere was small and not consistent.     

How does research address the design of innovative agricultural production systems at the farm level? A review

In trying to respond to societal demands for sustainable development, farming systems worldwide face a range of environmental, technical and economic challenges. These challenges call for renewed methodologies that can be used to support farmers in designing innovative agricultural production systems at the farm level. This paper aims to analyze the various methods described in scientific literature. The review is based on the analysis of 80 reference papers published in international scientific journals between 1999 and 2010. We focused in particular on the purpose of the research, which fell into two broad categories: “design” and “design support”. We also examined the use of models to represent production systems and to evaluate ex-ante the impact of innovations on these systems’ functioning and performance. In so doing, we developed a classification system to organize the studies into five sub-categories according to the type of methodology followed, namely: prototyping and design modelling for design orientated studies; participation, support modelling and advisory for design-support orientated studies. We found that very few studies attempt to address the three main components of an innovation process in agricultural production systems (biotechnical processes, farm management, and advisory services) within a single research framework. We therefore developed such a framework by connecting the design and design support orientations together with biotechnical research and conducting integrated research both at farm and advisory service levels.     

Uncommon acute neurologic presentation of canine distemper in 4 adult dogs

Four uncommon cases of canine distemper (CD) were diagnosed in vaccinated adult dogs. All dogs had acute onset of neurologic signs, including seizures, abnormal mentation, ataxia, and proprioceptive deficits. Polymerase chain reaction for CD virus was positive on cerebrospinal fluid in 2 cases. Due to rapid deterioration the dogs were euthanized and CD was confirmed by postmortem examination.     

Effects of dairy husbandry practices and farm types on raw milk quality collected by different categories of dairy processors in the Peruvian Andes

In developing countries, milk quality is often mismanaged in relation to husbandry practices, collection logistics, and the production of small batches. This paper investigates how the management of milk quality from farm to dairy processor impacts on both chemical and hygienic indicators, in a context characterized by farm scale diversity, the co-existence of formal and informal markets, and high milk demand. It is based on an analysis of the chemical and hygienic quality of milk samples collected over a 12-month period from 20 farms and three dairy processors. Data from the farmers’ husbandry practices and the logistics of milk collection were also collected. A large range of quality profiles and farming practices were observed. This diversity is explained by rainfall and temperature pattern, farm size which affects hygienic quality, and lack of efficient logistics between farms and dairy processors. The findings indicate that in a context of high demand for milk and poor private and public regulations, milk quality is impacted upon by poor stakeholders’ management practices.     

The effects of crop load and irrigation rate in the oil accumulation stage on oil yield and water relations of ‘Koroneiki’ olives

The interactions between irrigation rates applied during the oil accumulation stage and crop load were studied in a six-year-old very-high-density Koroneiki (Olea europaea L.) orchard. Five irrigation rates, determined as thresholds of midday stem water potential, were applied from July 1st until harvest in 2008 and 2009 and from July 1st to the end of September in 2010. Oil yield increased with increasing crop load in all the irrigation treatments. Oil yield did not respond to increasing irrigation at very low crop load and the higher the crop load the higher the response to irrigation. There was no response to irrigation at the lowest crop loads, but the higher the irrigation rate the higher the oil yield at high crop loads. The predicted commercial oil yield at common fruit counts increased from 1.99 t/ha at the lowest irrigation rate to 3.06 t/ha at the highest irrigation rate. Stomatal conductance decreased with decreasing stem water potential but leveled off at 30–60 mmol m^?2 s^?1 at stem water potential values lower than ?4.0 MPa. High crop load increased stomatal conductance and decreased stem water potential relative to low crop load at low and medium irrigation rates. The effect of crop load on water relations became evident by the end of August and was well pronounced at the beginning of October. Physiological and irrigation water management implications related to the interactions between tree water status and crop load are discussed.     

The spleen of Zaedyus pichiy, (Mammalia,Dasypodidae): a light and electron microscopic study

Armadillos are ancient mammals important as models for biomedical, evolutive and ecological studies, because they have adaptive and primitive morpho-physiological characteristics. In this work we study the splenic microarchitecture of the 'Patagonian Piche', Zaedyus pichiy, as an attempt to understand the relationship between the organizational plan of the organ and the particular features of this species. The organ samples were classically processed for light and electron microscopic study. The microanatomy of the organ as well as its different cell types are studied. The spleen is non-sinusoidal, with the typical arrangement for storage functions. White pulp is well defined. Red pulp is a meshwork of circulating, immunocompetent and haemopoietic cells. The general structure of the organ agrees with the semi-fossorial habit and the adaptability of the species. Comparative aspects with other armadillos or other less specialized groups are discussed. Persistence of haemopoietic spleen activity in the adult suggests the existence of specific inductive functions of the stroma. Better knowledge of spleen structure and function in ancient mammals may give important information about their phylogeny.     

An ancillary tool for the diagnosis of amyloid A amyloidosis in a variety of domestic and wild animals

Immunohistochemistry, the standard method for diagnosing amyloid A (AA) amyloidosis, is limited in animals because it requires a large array of animal-specific anti-AA antibodies, not commercially available. The Shtrasburg method (SH method) is a highly specific and sensitive technique, helping in the diagnosis and determination of AA amyloidosis in humans. The aim of this study is to determine whether the SH method is applicable in the diagnosis of AA amyloidosis in a variety of animals. Tissue samples were obtained from animals suffering from spontaneous or experimentally induced AA amyloidosis (mice, hamsters, guinea pigs, cheetahs, cats, cows, ducks, a dog, a goose, a chicken, and a turaco). Detection of the amyloid and quantitative evaluation were performed using Congo red staining, and specific AA typing was performed by the potassium permanganate technique. The studied tissues were subjected to the SH method, which confirmed the AA nature of the amyloid deposit, by displaying in polyacrylamide gel electrophoresis protein bands consistent with the molecular weight of the species-specific AA, in all the animals examined, except mice, hamsters, and guinea pigs. N-terminal analysis of these bands corroborated their AA origin. We conclude that the SH method may be used as an ancillary simple tool for the diagnosis of AA amyloidosis in a large number of domestic and wild animals. Moreover, our findings further increase the feasibility of applying this method in humans.