Arthropod diversity and community structure in relation to land use in the mekong delta, vietnam

Declining biodiversity in agro-ecosystems, caused by intensification of production or expansion of monocultures, is associated with the emergence of agricultural pests. Understanding how land-use and management control crop-associated biodiversity is, therefore, one of the key steps towards the prediction and maintenance of natural pest-control. Here we report on relationships between land-use variables and arthropod community attributes (for example, species diversity, abundance and guild structure) across a diversification gradient in a rice-dominated landscape in the Mekong delta, Vietnam. We show that rice habitats contained the most diverse arthropod communities, compared with other uncultivated and cultivated land-use types. In addition, arthropod species density and Simpson's diversity in flower, vegetable and fruit habitats was positively related to rice cover in the local landscape. However, across the landscape as a whole, reduction in heterogeneity and the amount of uncultivated cover was associated, generally, with a loss of diversity. Furthermore, arthropod species density in tillering and flowering stages of rice was positively related to crop and vegetation richness, respectively, in the local landscape. Differential effects on feeding guilds were also observed in rice-associated communities with the proportional abundance of predators increasing and the proportional abundance of detritivores decreasing with increased landscape rice cover. Thus, we identify a range of rather complex, sometimes contradictory patterns concerning the impact of rice cover and landscape heterogeneity on arthropod community attributes. Importantly, we conclude that that land-use change associated with expansion of monoculture rice need not automatically impact diversity and functioning of the arthropod community.

Intra-specific variation affects the structure of the natural enemy assemblage attacking pea aphid colonies

1. Intra-specific variation in plant defence traits has been shown to profoundly affect herbivore community structure. Here we describe two experiments designed to test whether similar effects occur at higher trophic levels, by studying pea aphid–natural enemy interactions in a disused pasture in southern England. 2. In the first experiment, the numbers and identity of natural enemies attacking different monoclonal pea aphid colonies were recorded in a series of assays throughout the period of pea aphid activity. 3. In the summer assay, there was a significant effect of clone on the numbers of aphidophagous hoverfly larvae and the total number of non-hoverfly natural enemies recruited. Clone also appeared to influence the attack rate suffered by the primary predator in the system, the hoverfly Episyrphus balteatus, by Diplazon laetatorius, an ichneumonid parasitoid. Colonies were generally driven to extinction by hoverfly attack, resulting in the recording of low numbers of parasitoids and entomopathogens, suggesting intense intra-guild predation. 4. To further examine the influence of clonal variation on the recruitment of natural enemies, a second experiment was performed to monitor the temporal dynamics of community development. Colonies were destructively sampled every other day and the numbers of natural enemies attacking aphid colonies were recorded. These data demonstrated that clonal variation influenced the timing, abundance, and identity of natural enemies attacking aphid colonies. 5. Taken together, these data suggest that clonal variation may have a significant influence on the patterns of interactions between aphids and their natural enemies, and that such effects are likely to affect our understanding of the ecology and biological control of these insect herbivores.

Glucosinolates in brassica vegetables: the influence of the food supply chain on intake, bioavailability and human health

Glucosinolates (GLSs) are found in Brassica vegetables. Examples of these sources include cabbage, Brussels sprouts, broccoli, cauliflower and various root vegetables (e.g. radish and turnip). A number of epidemiological studies have identified an inverse association between consumption of these vegetables and the risk of colon and rectal cancer. Animal studies have shown changes in enzyme activities and DNA damage resulting from consumption of Brassica vegetables or isothiocyanates, the breakdown products (BDP) of GLSs in the body. Mechanistic studies have begun to identify the ways in which the compounds may exert their protective action but the relevance of these studies to protective effects in the human alimentary tract is as yet unproven. In vitro studies with a number of specific isothiocyanates have suggested mechanisms that might be the basis of their chemoprotective effects. The concentration and composition of the GLSs in different plants, but also within a plant (e.g. in the seeds, roots or leaves), can vary greatly and also changes during plant development. Furthermore, the effects of various factors in the supply chain of Brassica vegetables including breeding, cultivation, storage and processing on intake and bioavailability of GLSs are extensively discussed in this paper.

Clinical trial: the effects of a trans-galactooligosaccharide prebiotic on faecal microbiota and symptoms in irritable bowel syndrome

Gut microflora-mucosal interactions may be involved in the pathogenesis of irritable bowel syndrome (IBS). To investigate the efficacy of a novel prebiotic trans-galactooligosaccharide in changing the colonic microflora and improve the symptoms in IBS sufferers. In all, 44 patients with Rome II positive IBS completed a 12-week single centre parallel crossover controlled clinical trial. Patients were randomized to receive either 3.5 g/d prebiotic, 7 g/d prebiotic or 7 g/d placebo. IBS symptoms were monitored weekly and scored according to a 7-point Likert scale. Changes in faecal microflora, stool frequency and form (Bristol stool scale) subjective global assessment (SGA), anxiety and depression and QOL scores were also monitored. The prebiotic significantly enhanced faecal bifidobacteria (3.5 g/d P < 0.005; 7 g/d P < 0.001). Placebo was without effect on the clinical parameters monitored, while the prebiotic at 3.5 g/d significantly changed stool consistency (P < 0.05), improved flatulence (P < 0.05) bloating (P < 0.05), composite score of symptoms (P < 0.05) and SGA (P < 0.05). The prebiotic at 7 g/d significantly improved SGA (P < 0.05) and anxiety scores (P < 0.05). The galactooligosaccharide acted as a prebiotic in specifically stimulating gut bifidobacteria in IBS patients and is effective in alleviating symptoms. These findings suggest that the prebiotic has potential as a therapeutic agent in IBS.

Reconstruction of historical pollination rates reveals linked declines of pollinators and plants

Widespread reports of low pollination rates suggest a recent anthropogenic decline in pollination that could threaten natural and agricultural ecosystems. Nevertheless, unequivocal evidence for a decline in pollination over time has remained elusive because it was not possible to determine historical pollination rates. Here we demonstrate a widely applicable method for reconstructing historical pollination rates, thus allowing comparison with contemporary rates from the same sites. We focused on the relationship between the oil-collecting bee Rediviva peringueyi (Melittidae) and the guild of oil-secreting orchid species (Coryciinae) that depends on it for pollination. The guild is distributed across the highly transformed and fragmented lowlands of the Cape Region of South Africa. We show that rehydrated herbarium specimens of Pterygodium catholicum, the most abundant member of the guild, contain a record of past pollinator activity in the form of pollinarium removal rates. Analysis of a pollination time series showed a recent decline in pollination on Signal Hill, a small urban conservation area. The same herbaria contain historical species occurrence data. We analyzed this data and found that there has been a contemporaneous shift in orchid guild composition in urban areas due to the local extirpation of the non-clonal species, consistent with their greater dependence on seeds and pollination for population persistence.

Phenotypic and genotypic characterization of avian Escherichia coli O86:K61 isolates possessing a gamma-like intimin

Escherichia coli O86:K61 has long been associated with outbreaks of infantile diarrhea in humans and with diarrheal disease in many animal species. Studies in the late 1990s identified E. coli 086:K61 as the cause of mortality in a variety of wild birds, and in this study, 34 E. coli 086:K61 isolates were examined. All of the isolates were nonmotile, but most elaborated at least two morphologically distinct surface appendages that were confirmed to be type I and curli fimbriae. Thirty-three isolates were positive for the eaeA gene encoding a gamma type of intimin. No phenotypic or genotypic evidence was obtained for elaboration of Shiga-like toxins, but most isolates possessed the gene coding for the cytolethal distending toxin. Five isolates were selected for adherence assays performed with tissue explants and HEp-2 cells, and four of these strains produced attaching and effacing lesions on HEp-2 cells and invaded the cells, as determined by transmission electron microscopy. Two of the five isolates were inoculated orally into 1-day-old specific-pathogen-free chicks, and both of these isolates colonized, invaded, and persisted well in this model. Neither isolate produced attaching and effacing lesions in chicks, although some pathology was evident in the alimentary tract. No deaths were recorded in inoculated chicks. These findings are discussed in light of the possibility that wild birds are potential zoonotic reservoirs of attaching and effacing E. coli.

Convergent evolution of floral signals underlies the success of Neotropical orchids

The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry—a form of Batesian mimicry that involves multiple models and is more complex than a simple one model–one mimic system—operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant–animal interactions.

Human microbiota in health and disease

Each human body plays host to a microbial population which is both numerically vast (at around 1014 microbial cells) and phenomenally diverse (over 1,000 species). The majority of the microbial species in the gut have not been cultured but the application of culture-independent approaches for high throughput diversity and functionality analysis has allowed characterisation of the diverse microbial phylotypes present in health and disease. Studies in monozygotic twins, showing that these retain highly similar microbiota decades after birth and initial colonisation, are strongly indicative that diversity of the microbiome is host-specific and affected by the genotype. Microbial diversity in the human body is reflected in both richness and evenness. Diversity increases steeply from birth reaching its highest point in early adulthood, before declining in older age. However, in healthy subjects there appears to be a core of microbial phylotypes which remains relatively stable over time. Studies of individuals from diverse geopraphies suggest that clusters of intestinal bacterial groups tend to occur together, constituting ‘enterotypes’. So variation in intestinal microbiota is stratified rather than continuous and there may be a limited number of host/microbial states which respond differently to environmental influences. Exploration of enterotypes and functional groups may provide biomarkers for disease and insights into the potential for new treatments based on manipulation of the microbiome. In health, the microbiota interact with host defences and exist in harmonious homeostasis which can then be disturbed by invading organisms or when ‘carpet bombing’ by antibiotics occurs. In a portion of individuals with infections, the disease will resolve itself without the need for antibiotics and microbial homeostasis with the host’s defences is restored. The administration of probiotics (live microorganisms which when administered in adequate amounts confer a health benefit on the host) represents an artificial way to enhance or stimulate these natural processes. The study of innate mechanisms of antimicrobial defence on the skin, including the production of numerous antimicrobial peptides (AMPs), has shown an important role for skin commensal organisms. These organisms may produce AMPs, and also amplify the innate immune responses to pathogens by activating signalling pathways and processing host produced AMPs. Research continues into how to enhance and manipulate the role of commensal organisms on the skin. The challenges of skin infection (including diseases caused by multiply resistant organisms) and infestations remain considerable. The potential to re-colonise the skin to replace or reduce pathogens, and exploring the relationship between microbiota elsewhere and skin diseases are among a growing list of research targets. Lactobacillus species are among the best known ‘beneficial’ bacterial members of the human microbiota. Of the approximately 120 species known, about 15 are known to occur in the human vagina. These organisms have multiple properties, including the production of lactic acid, hydrogen peroxide and bacteriocins, which render the vagina inhospitable to potential pathogens. Depletion of the of the normal Lactobacillus population and overgrowth of vaginal anaerobes, accompanied by the loss of normal vaginal acidity can lead to bacterial vaginosis – the commonest cause of abnormal vaginal discharge in women. Some vaginal anaerobes are associated with the formation of vaginal biofilms which serve to act as a reservoir of organisms which persists after standard antibiotic therapy of bacterial vaginosis and may help to account for the characteristically high relapse rate in the condition. Administration of Lactobacillus species both vaginally and orally have shown beneficial effects in the treatment of bacterial vaginosis and such treatments have an excellent overall safety record. Candida albicans is a frequent coloniser of human skin and mucosal membranes, and is a normal part of the microbiota in the mouth, gut and vagina. Nevertheless Candida albicans is the most common fungal pathogen worldwide and is a leading cause of serious and often fatal nosocomial infections. What turns this organism from a commensal to a pathogen is a combination of increasing virulence in the organism and predisposing host factors that compromise immunity. There has been considerable research into the use of probiotic Lactobacillus spp. in vaginal candidiasis. Studies in reconstituted human epithelium and monolayer cell cultures have shown that L. rhamnosus GG can protect mucosa from damage caused by Candida albicans, and enhance the immune responses of mucosal surfaces. Such findings offer the promise that the use of such probiotic bacteria could provide new options for antifungal therapy. Studies of changes of the human intestinal microbiota in health and disease are complicated by its size and diversity. The Alimentary Pharmabiotic Centre in Cork (Republic of Ireland) has the mission to ‘mine microbes for mankind’ and its work illustrates the potential benefits of understanding the gut microbiota. Work undertaken at the centre includes: mapping changes in the microbiota with age; studies of the interaction between the microbiota and the gut; potential interactions between the gut microbiota and the central nervous system; the potential for probiotics to act as anti-infectives including through the production of bacteriocins; and the characterisation of interactions between gut microbiota and bile acids which have important roles as signalling molecules and in immunity. The important disease entity where the role of the gut microbiota appears to be central is the Irritable Bowel Syndrome (IBS). IBS patients show evidence of immune activation, impaired gut barrier function and abnormal gut microbiota. Studies with probiotics have shown that these organisms can exert anti-inflammatory effects in inflammatory bowel disease and may strengthen the gut barrier in IBS of the diarrhoea-predominant type. Formal randomised trials of probiotics in IBS show mixed results with limited benefit for some but not all. Studies confirm that administered probiotics can survive and temporarily colonise the gut. They can also stimulate the numbers of other lactic acid bacilli in the gut, and reduce the numbers of pathogens. However consuming live organisms is not the only way to influence gut microbiota. Dietary prebiotics are selectively fermented ingredients that can change the composition and/or activity of the gastrointestinal microbiota in beneficial ways. Dietary components that reach the colon, and are available to influence the microbiota include poorly digestible carbohydrates, such as non-starch polysaccharides, resistant starch, non-digestible oligosaccharides (NDOs) and polyphenols. Mixtures of probiotic and prebiotic ingredients that can selectively stimulate growth or activity of health promoting bacteria have been termed ‘synbiotics’. All of these approaches can influence gut microbial ecology, mainly to increase bifidobacteria and lactobacilli, but metagenomic approaches may reveal wider effects. Characterising how these changes produce physiological benefits may enable broader use of these tactics in health and disease in the future. The current status of probiotic products commercially available worldwide is less than ideal. Prevalent problems include misidentification of ingredient organisms and poor viability of probiotic microorganisms leading to inadequate shelf life. On occasions these problems mean that some commercially available products cannot be considered to meet the definition of a probiotic product. Given the potential benefits of manipulating the human microbiota for beneficial effects, there is a clear need for improved regulation of probiotics. The potential importance of the human microbiota cannot be overstated. ‘We feed our microbes, they talk to us and we benefit. We just have to understand and then exploit this.’ (Willem de Vos).

Local and landscape effects on bee functional guilds in pigeon pea crops in Kenya

Pollinators face many challenges within agricultural systems due to landscape changes and intensification which can affect resource availability that can impact pollination services. This paper examines pigeon pea pollination and considers how landscape context and agricultural intensification in terms of pesticide use affects the abundance of bees characterized by species guilds on crops. The study was conducted on six paired farms across a gradient of habitat complexity based on the distance of each farm from adjacent semi-natural vegetation in Kibwezi Sub-county, Kenya. The study found that farms which do not use insecticides in farm management, but are in close proximity to natural habitat have greater bee guild abundance, but at further distances, overall abundance is reduced with or without insecticide use. At 1 km landscape radius, the complexity of habitats but not patch size had a positive impact on the abundance of cavity nesting bees and mason bees, which can be attributed to the interspersion of the small-holder farms with semi-natural habitats across the landscapes producing mosaics of heterogeneous habitats. The study revealed the strongest relationships between fruit set and bee abundance to be with the carpenter bee, social bee and solitary bee guilds, which are among the most abundant bees visiting pigeon pea flowers in this system. Our findings provide the foundation for conservation efforts by identifying which bee guilds pollinated pigeon peas. From this study, we suggest managing the floral and nesting resources that would best support the most abundant crop pollinators, and also reducing insecticide application to the crop.

Digestive morphophysiology of Gryllodes sigillatus (Orthoptera: Gryllidae)

The evolution of the digestive system in the Order Orthoptera is disclosed from the study of the morphophysiology of the digestive process in its major taxa. This paper deals with a cricket representing the less known suborder Ensifera Most amylase and trypsin activities occur in crop and caeca. respectively. Maltase and aminopeptidase are found in soluble and membrane-bound forms in caeca, with aminopeptidase also occurring in ventriculus. Amaranth was orally fed to Gryllodes sigillatus adults or injected into their haemolymph. The experiments were performed with starving and feeding insects with identical results. Following feeding of the dye the luminal side of the most anterior ventriculus (and in lesser amounts the midgut caeca) became heavily stained. In injected insects, the haemal side of the most posterior ventriculus was stained This suggested that the anterior ventriculus is the main site of water absorption (the caeca is a secondary one). whereas the posterior ventriculus secretes water into the gut. Thus, a putative counter-current flux of fluid from posterior to anterior ventriculus may propel digestive enzyme recycling. This was confirmed by the finding that digestive enzymes are excreted at a low rate. The fine structure of midgut caeca and ventriculus cells revealed that they have morphological features that may be related to their involvement in secretion (movement from cell to lumen) and absorption (movement from lumen to cell) of fluids. Furthermore, morphological data showed that both merocrine and apocrine secretory mechanisms occur in midgut cells. The results showed that cricket digestion differs from that in grasshopper in having (1) more membrane-bound digestive enzymes; (2) protein digestion slightly displaced toward the ventriculus; (3) midgut fluxes, and hence digestive enzyme recycling, in both starved and fed insects. (C) 2009 Elsevier Ltd. All rights reserved.

Study of metals transfer from environment using teeth as biomonitor

We investigated chronic incorporation of metals in individuals from poor families, living in a small, restrict and allegedly contaminated area in Sao Paulo city, the surroundings of the Guarapiranga dam, responsible for water supply to 25% of the city population. A total of 59 teeth from individuals 7 to 60 years old were collected. The average concentrations of Pb, Cd, Fe, Zn, Mn, Ni and Cr were determined with an Atomic Absorption Spectrophotometer. The concentrations of all metals as function of the individuals` age exhibited a remarkable similarity: peaks between 7 and 10 years and sharply decreasing at higher ages, which could be attributed to alimentary habits and persistence to metals exposure all along the individuals` life span. From all the measured metals, lead and cadmium were a matter of much more concern since their measured values are close to the upper limits of the world wide averages. (C) 2009 Elsevier Ltd. All rights reserved.

POSTMARITAL RESIDENCE PRACTICE IN SOUTHERN BRAZILIAN COASTAL GROUPS: CONTINUITY AND CHANGE

The coastal plains of the States of Parana and Santa Catarina, in Southern Brazil, were first settled around 6000 B.P. by shellmound builders, a successful fisher-hunter-gatherer population that inhabited the coastal lowlands practically unchanged for almost five thousand years. Shellmounds were typically occupied as residential sites as well as cemeteries, and are usually associated with rich alimentary zones. Around 1200 B.P., the first evidence of ceramics brought from the interior is found in coastal areas, and together with ceramics there is a progressive abandonment of shellmound construction in favor of flat cold shallow sites. Here we consider if these changes were reflected in the postmarital residence practice of coastal groups, i.e., if the arrival or intensification of contact with groups from the interior resulted in changes in this aspect of social structure among the coastal groups. To test the postmarital residence practice we analyzed within-group variability ratios between males and females, following previous studies on the topic. and between-group, correlations between Mahalanobis distances and geographic distances. The results suggest that in the pre-ceramic series a matrilocal, postmarital residential system predominated, while in the ceramic period there was a shift toward patrilocality. This favors the hypothesis that the changes experienced by coastal groups after 1200 B.P. affected not only their economy and material culture, but important aspects of their sociopolitical organization as well.

Verdi's Settings of Shakespeare : from Play to Liberetto to Opera

As a Senior Scholar pursuing the topic, Verdi's Settings of Shakespeare: From Play to Libretto to Opera, I have endeavoured to study a project relevant to my majors, Music and English. During first semester, I carefully analysed Shakespeare's plays, Macbeth, Othello and Falstaff. The highlight of my project was in January when I travelled to New York City and spent the day working with the Metropolitan Opera Guild. I was also able to see a performance of Verdi's Othello with Jon Vickers in the lead role. During the second semester, I studied the musical aspects of the compositions. I spent time analysing musical passages and relating them to the plays and the operas. I was also able to continue my study of Italian, which I find extremely beneficial while studying Verdi's libretti. On Monday, 13th May, 1974, I gave a lecture presentation of my project. At this time, I showed slides of Metropolitan productions of the operas, presented my own rendition of five arias (in costume) and talked about comparisions between the plays and the operas. I applied for a Rotary Fellowship to take my project to Europe and am presently waiting to hear the results. If I do receive the fellowship, I am planning to spend a year studying the plays and operas in England and Italy. Afterwards, I hope to publish a paper explaining my findings. The paper is divided into six sections. The first section is an introduction which explains the period of Romanticism and its relationship to Shakespeare and Verdi. The second section is devoted to discussing the librettist for Macbeth, Francesco Piave. Following this section the opera Macbeth is discussed. Arrigo Boito, the librettist for Otello and Falstaff is discussed in the fourth section. The last two sections deal with Otello and Falstaff. I have also included a number of musical selections to better explain certain passages. My project has been invaluable to me. My Senior Scholar project has allowed me the freedom of independent study as well as a means of tying my majors together.

The development of a Defense System against Coxsackievirus B5 Infection in Suckling Mice

There are many viruses that are able to infect the alimentary tract of man. Little is known, however, about the mechanism of infection itself or the pathophysiology of the gut during infection. 'The research reported here is concerned with the differences in susceptibility among suckling mice of various ages inoculated by the intraperitoneal and intragastric routes. Since the normal mode of entry of many viruses to the gut is via the oral route, Coxsackievirus B5, a human enterovirus which does attack this way, was utilized. It is a non-tumor producing RNA virus that has been shown to act similarly in the mouse and human. The virus was pooled in HeLa cell cultures and titered by a plaquing assay in the same cell cultures. CD-l mice, 10, 14, 18, and 22 days old , were infected either orally or intraperitoneally with 5.0 x 10^10 (10 day old animals) and 1.0 x10^9 plaque forming units per animal. Dissections were done at 1 and 3 days post infection with samples of the blood, heart, liver, and gut being taken from each animal. Each sample was titered individually and the data presented as an average of six samples. As a result of previous work, it is known that the gut of a newborn mouse isn't able to decrease the concentration of the infecting dose and therefore provides no defense against an enteric infection with Coxsackievirus B5. In contrat, mature mice are able to reduce the amount of viral dissemination across the gut as well as inhibit replication after absorption has occurred. The results of this study indicate that there is a double barrier system developing in suckling mice that is involved with and directly related to the gastrointestinal tract The first part of this defense is the inhibition of penetration of virus across the gut when the primary site of' infection is the intestinal mucosa. This mechanism develops sometime around 20 to 22 days after birth. At about 16-18 days of age, suckling mice that were challenged intragastrically are able to stop active replication and initiate clearance of virus from the systemic circulation. There are many factors that might contribute to the marked decrease in susceptibility with age of suckling mice. Some of these or possibly a combination of these factors might explain the defense mechanisms described above, but to date, the chemistry or mechanical functioning of the gastrointestinal barrier to enteric viral infection is unknown.

But a Whimper

In my last rustication, I opined the details of the 300-page Google Book Deal settlement made in late 2008 between Google and authors and publishers vis-à-vis Google’s massive digitization scheme (those cases, viz., Authors Guild et al v. Google and McGraw-Hill et al v. Google).