Mapping the structural core of human cerebral cortex.

Structurally segregated and functionally specialized regions of the human cerebral cortex are interconnected by a dense network of cortico-cortical axonal pathways. By using diffusion spectrum imaging, we noninvasively mapped these pathways within and across cortical hemispheres in individual human participants. An analysis of the resulting large-scale structural brain networks reveals a structural core within posterior medial and parietal cerebral cortex, as well as several distinct temporal and frontal modules. Brain regions within the structural core share high degree, strength, and betweenness centrality, and they constitute connector hubs that link all major structural modules. The structural core contains brain regions that form the posterior components of the human default network. Looking both within and outside of core regions, we observed a substantial correspondence between structural connectivity and resting-state functional connectivity measured in the same participants. The spatial and topological centrality of the core within cortex suggests an important role in functional integration.

Gut symbionts from distinct hosts exhibit genotoxic activity via divergent colibactin biosynthetic pathways.

Secondary metabolites produced by nonribosomal peptide synthetase (NRPS) or polyketide synthase (PKS) pathways are chemical mediators of microbial interactions in diverse environments. However, little is known about their distribution, evolution, and functional roles in bacterial symbionts associated with animals. A prominent example is "colibactin", a largely unknown family of secondary metabolites produced by Escherichia coli via a hybrid NRPS-PKS biosynthetic pathway, inflicting DNA damage upon eukaryotic cells and contributing to colorectal cancer and tumor formation in the mammalian gut. Thus far, homologs of this pathway have only been found in closely related Enterobacteriaceae, while a divergent variant of this gene cluster was recently discovered in a marine alphaproteobacterial Pseudovibrio strain. Herein, we sequenced the genome of Frischella perrara PEB0191, a bacterial gut symbiont of honey bees, and identified a homologous colibactin biosynthetic pathway related to those found in Enterobacteriaceae. We show that the colibactin genomic island (GI) has conserved gene synteny and biosynthetic module architecture across F. perrara, Enterobacteriaceae and the Pseudovibrio strain. Comparative metabolomics analyses of F. perrara and E. coli further reveal that these two bacteria produce related colibactin pathway-dependent metabolites. Finally, we demonstrate that F. perrara, like E. coli, causes DNA damage in eukaryotic cells in vitro in a colibactin pathway-dependent manner. Together, these results support that divergent variants of the colibactin biosynthetic pathway are widely distributed among bacterial symbionts, producing related secondary metabolites and likely endowing its producer with functional capabilities important for diverse symbiotic associations.

Metabolic effects of fructose and the worldwide increase in obesity.

While virtually absent in our diet a few hundred years ago, fructose has now become a major constituent of our modern diet. Our main sources of fructose are sucrose from beet or cane, high fructose corn syrup, fruits, and honey. Fructose has the same chemical formula as glucose (C(6)H(12)O(6)), but its metabolism differs markedly from that of glucose due to its almost complete hepatic extraction and rapid hepatic conversion into glucose, glycogen, lactate, and fat. Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity. Hepatic de novo lipogenesis and lipotoxicity, oxidative stress, and hyperuricemia have all been proposed as mechanisms responsible for these adverse metabolic effects of fructose. Although there is compelling evidence that very high fructose intake can have deleterious metabolic effects in humans as in rodents, the role of fructose in the development of the current epidemic of metabolic disorders remains controversial. Epidemiological studies show growing evidence that consumption of sweetened beverages (containing either sucrose or a mixture of glucose and fructose) is associated with a high energy intake, increased body weight, and the occurrence of metabolic and cardiovascular disorders. There is, however, no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects. There has also been much concern that consumption of free fructose, as provided in high fructose corn syrup, may cause more adverse effects than consumption of fructose consumed with sucrose. There is, however, no direct evidence for more serious metabolic consequences of high fructose corn syrup versus sucrose consumption.

Functional response of Telenomus remus Nixon(Hymenoptera, Scelionidae) to Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) eggs: effect of female age

Functional response of Telenomus remus Nixon (Hymenoptera, Scelionidae) to Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) eggs: effect of female age. Functional response of 24-h and 48-h-old Telenomus remus adults was studied on Spodoptera frugiperda eggs. The study was carried out in climatic chamber regulated at 25 ± 1°C, 70 ± 10% RH and 12:12h (L: D). Females of T. remus were honey fed and individualized in glass vials along with 25, 50, 75, 100, 150, 200, 250 or 300 eggs of S. frugiperda for 24 h. Complete randomized design with ten replications was adopted. The parameters evaluated to construct the functional response curve were daily average parasitism, searching rate and oviposition time. It was observed that the higher the egg density, the higher the parasitism for 24-h and 48-h-old females although there was a tendency of parasitism stabilization at 150-egg density. The results showed a type II functional response curve for both 24-h and 48-h-old female.

Influence of age and diet on the performance of Cephalonomia stephanoderis (Hymenoptera, Bethylidae) a parasitoid of the coffee berry borer, Hypothenemus hampei (Coleoptera, Curculionidae)

The importance of age and feeding on the performance of Cephalonomia stephanoderis (Hymenoptera, Bethylidae), a parasitoid of the coffee berry borer, Hypothenemus hampei (Coleoptera, Curculionidae) was investigated in the laboratory. Groups of female parasitoids were subject to the following treatments: a group fed during one, five and ten days after emergence of adults with coffee borer larvae; another group fed only with honey solution during five days after emergence; and as a control, a third group was kept without food for five days. At the end of each treatment, survivorship, parasitoid activity (walking and flying capacity in an arena), search capacity for finding coffee borer-infested berries, host feeding and oviposition (on immature hosts), were assessed. Unfed females showed a significant decrease in survivorship compared to individuals that were fed. The type of meal (insects or honey) did not significantly influence parasitoid activity, search and oviposition capacities. Females fed with honey solution significantly consumed less immature coffee borers. Younger females (one day old) walked and flew out of the arena significantly faster than older ones (5 and 10 days old). Implications of these results are discussed on the performance of C. stephanoderis as a biological control agent of the coffee berry borer.

Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani) (Hymenoptera, Pteromalidae)

Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani) (Hymenoptera, Pteromalidae). Theories predict that females of parasitoid wasps would adjust the offspring sex ratio to environmental conditions in the oviposition patch, but the diet and age of females would also affect the sex ratio adjustment. Our focus was to test the effects of female diet and age on offspring sex ratio of the solitary parasitoid wasp, Pachycrepoideus vindemmiae (Rondani, 1875). Our results showed that females fed with honey had significantly less female biased offspring sex ratio than those fed only with water. Offspring sex ratio (male percentage) decreased with female age or female longevity at the beginning of oviposition but increased at the end. There should be a sperm limitation in P. vindemmiae females at the end of oviposition, and a higher frequency of unfertilized eggs were laid then. Females also laid more unfertilized eggs at the beginning of oviposition, which would be necessary to insure the mating among offspring. Male offspring developed faster and emerged earlier, which would also reduce the risk of virginity in offspring with female-biased sex ratio.

Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera,Apidae)

Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera, Apidae). Metamorphosis in holometabolous insects occurs through two subsequent molting cycles: pupation (metamorphic molt) and adult differentiation (imaginal molt). The imaginal molt in Apis mellifera L. was recently investigated in both histological and physiological-molecular approaches. Although the metamorphic molt in this model bee is extremely important to development, it is not well-known yet. In the current study we used this stage as an ontogenetic scenario to investigate the transcriptional profile of the gene Amlac2, which encodes a laccase with an essential role in cuticle differentiation. Amlac2 expression in epidermis was contrasted with the hemolymph titer of ecdysteroid hormones and with the most evident morphological events occurring during cuticle renewal. RT-PCR semiquantitative analyses using integument samples revealed increased levels of Amlac2 transcripts right after apolysis and during the subsequent pharate period, and declining levels near pupal ecdysis. Compared with the expression of a cuticle protein gene, AmelCPR14, these results highlighted the importance of the ecdysteroid-induced apolysis as an ontogenetic marker of gene reactivation in epidermis for cuticle renewal. The obtained results strengthen the comprehension of metamorphosis in Apis mellifera. In addition, we reviewed the literature about the development of A. mellifera, and emphasize the importance of revising the terminology used to describe honey bee molting cycles.

Mehiläisen immuunipolypeptidit

Summary: Inducible immune polypeptides of the honey bee

Enterococcus faecalis -tartunta mehiläisellä

Summary: Enterococcus faecalis infection in the honey bee, Apis mellifera L.

Parasitoid wasps: from natural history to genomic studies.

The sequencing of three Nasonia genomes provides new insights on the molecular signature associated with parasitoid lifestyle, allows comparison with the social honey bee, and enables the identification of genes underlying between-species and sex-specific differences.

Water Heating, 2011

Although there are many ways to cut you water heating bills, the all fall into two broad categories: reducing the amount of hot water you use and making your water heating system more efficient. Fortunately, there are several strategies that can help you consume less energy and save money - and still meet you hot water needs without sacrificing comfort or practicality. The booklet was designed to answer common questions about hot water systems and to provide you with the information necessary to make informed decision about a wide variety of topics, ranging from repairing hot water faucet leaks an insulation water supply pipes to installing low-flow shower heads and tuning you your existing water heather. You'll also find details on what to consider when it's time to go comparison shopping for a new water heater-including an evaluation of the alternatives to the common gas or electric storage tank unit that's found in the majority of homes in Iowa and across the country.

Life-history evolution and the polyphenic regulation of somatic maintenance and survival.

Here we discuss life-history evolution from the perspective of adaptive phenotypic plasticity, with a focus on polyphenisms for somatic maintenance and survival. Polyphenisms are adaptive discrete alternative phenotypes that develop in response to changes in the environment. We suggest that dauer larval diapause and its associated adult phenotypes in the nematode (Caenorhabditis elegans), reproductive dormancy in the fruit fly (Drosophila melanogaster) and other insects, and the worker castes of the honey bee (Apis mellifera) are examples of what may be viewed as the polyphenic regulation of somatic maintenance and survival. In these and other cases, the same genotype can--depending upon its environment--express either of two alternative sets of life-history phenotypes that differ markedly with respect to somatic maintenance, survival ability, and thus life span. This plastic modulation of somatic maintenance and survival has traditionally been underappreciated by researchers working on aging and life history. We review the current evidence for such adaptive life-history switches and their molecular regulation and suggest that they are caused by temporally and/or spatially varying, stressful environments that impose diversifying selection, thereby favoring the evolution of plasticity of somatic maintenance and survival under strong regulatory control. By considering somatic maintenance and survivorship from the perspective of adaptive life-history switches, we may gain novel insights into the mechanisms and evolution of aging.

Taudinaiheuttajien, lääkkeiden ja vierasaineiden vaikutuksista mehiläisen (Apis mellifera L.) tartunnanvastaiseen puolustukseen

Summary: Immunotoxic and immunomodulatory aspects of pathogens, drugs and xenobiotics in protection of the honey bee (Apis mellifera L.) to infections