Oral Candida colonization in patients with chronic periodontitis. Is there any relationship?

Background

Candida can be implicated in the pathology of chronic periodontitis.

Construction of a Panel of Canine–Rodent Hybrid Cell Lines for Use in Partitioning of the Canine Genome

We have constructed a collection of canine–rodent microcell hybrid cell lines by fusion of canine fibroblast microcell donors with immortalized rodent recipient cells. Characterization of the hybrid cell lines using a combination of fluorescencein situhybridization and PCR analysis of canine microsatellite repeat sequences allowed selection of a panel of hybrids in which most canine chromosomes are represented. Approximately 90% of genetic markers and genes that were tested could be assigned to 1 of 31 anonymous canine chromosome groups, based on common patterns of retention in the hybrid set. Many of these putative chromosome groups have now been validated by linkage analysis. This panel of cell lines provides a tool for development of genetic, physical, and comparative maps of the canine genome.     

Abundance patterns of two Oropsylla (Ceratophyllidae: Siphonaptera) species on black-tailed prairie dog (Cynomys ludovicianus) hosts.

Behavioral, genetic, and immune variation within a host population may lead to aggregation of parasites whereby a small proportion of hosts harbor a majority of parasites. In situations where two or more parasite species infect the same host population there is the potential for interaction among parasites that could potentially influence patterns of aggregation through either competition or facilitation. We studied the occurrence and abundance patterns of two congeneric flea species on black-tailed prairie dog (Cynomys ludovicianus) hosts to test for interactions among parasite species. We live-trapped prairie dogs on ten sites in Boulder County, CO and collected their fleas. We found a non-random, positive association between the two flea species, Oropsylla hirsuta and O. tuberculata cynomuris; hosts with high loads of one flea species had high loads of the second species. This result suggests that there is no interspecific competition among fleas on prairie dog hosts. Host weight had a weak negative relationship to flea load and host sex did not influence flea load, though there were slight differences in flea prevalence and abundance between male and female C. ludovicianus. While genetic and behavioral variation among hosts may predispose certain individuals to infection, our results indicate apparent facilitation among flea species that may result from immune suppression or other flea-mediated factors.     

Anthropocene anthropology: reconceptualizing contemporary global change

The Anthropocene is the scientific label given by earth scientists to the current epoch of unprecedented anthropogenic planetary change. The Anthropocene is also a political label designed to call attention to this change and evolving notions of agency and responsibility in contemporary life. This article critically explores what I call ‘the Anthropocene idea’ and the condition of ‘Anthropocene spaces’ through selected anthropological writing about recent planetary change and through analysis of current events in a specific ‘vulnerable’ location. By considering recent events in The Bahamas, I arrive at an orientation that I call simply Anthropocene anthropology. Rather than advocating for the creation of a new subfield of research, this mode of engagement offers an open‐ended conceptual framework for the critical examination of the Anthropocene idea as it influences the symbolic and material realities of contemporary Anthropocene spaces.     

The proteolysis adaptor,NblA, binds to the N-terminus of β-phycocyanin: Implications for the mechanism of phycobilisome degradation

Phycobilisome (PBS) complexes are massive light-harvesting apparati in cyanobacteria that capture and funnel light energy to the photosystem. PBS complexes are dynamically degraded during nutrient deprivation, which causes severe chlorosis, and resynthesized during nutrient repletion. PBS degradation occurs rapidly after nutrient step down, and is specifically triggered by non-bleaching protein A (NblA), a small proteolysis adaptor that facilitates interactions between a Clp chaperone and phycobiliproteins. Little is known about the mode of action of NblA during PBS degradation. In this study, we used chemical cross-linking coupled with LC-MS/MS to investigate the interactions between NblA and phycobiliproteins. An isotopically coded BS³ cross-linker captured a protein interaction between NblA and β-phycocyanin (PC). LC-MS/MS analysis identified the amino acid residues participating in the binding reaction, and demonstrated that K⁵² in NblA is cross-linked to T² in β-PC. These results were modeled onto the existing crystal structures of NblA and PC by protein docking simulations. Our data indicate that the C-terminus of NblA fits in an open groove of β-PC, a region located inside the central hollow cavity of a PC rod. NblA may mediate PBS degradation by disrupting the structural integrity of the PC rod from within the rod. In addition, M¹-K⁴⁴ and M¹-K⁵² cross-links between the N-terminus of NblA and the C-terminus of NblA are consistent with the NblA crystal structure, confirming that the purified NblA is structurally and biologically relevant. These findings provide direct evidence that NblA physically interacts with β-PC.     

Tomato belowground–aboveground interactions: <Emphasis Type="Italic">Rhizophagus irregularis</Emphasis> affects foraging behavior and life history traits of the predator <Emphasis Type="Italic">Macrolophus pygmaeus</Emphasis> (Hemiptera: Miridae)

In recent years, studies on arbuscular mycorrhizal fungi (AMF) have been revealing that the belowground symbiosis can influence the performance of aboveground herbivores and their natural enemies through its effects on the host plant. In this study, we tested whether the colonization of tomato plants by the arbuscular mycorrhizal fungus Rhizophagus irregularis (Syn. Glomus intraradices Schenk and Smith) (Glomeromycota: Glomeraceae) affects the performance of the zoophytophagous mirid bug Macrolophus pygmaeus Rambur (Hemiptera: Miridae). Mycorrhizal colonization in tomato plants positively influenced the predator host-plant acceptance for feeding and oviposition, as well as nymphal survival and female weight. We hypothesize that AMF can modify mirid bug foraging behavior and performance.     

Collagen fibrillogenesis in tendon development: current models and regulation of fibril assembly

Tendons are collagen-based fibrous tissues that connect and transmit forces from muscle to bone. These tissues, which are high in collagen type I content, have been studied extensively to understand collagen fibrillogenesis. Although the mechanisms have not been fully elucidated, our understanding has continued to progress. Here, we review two prevailing models of collagen fibrillogenesis and discuss the regulation of the process by candidate cellular and extracellular matrix molecules. Although numerous molecules have been implicated in the regulation of collagen fibrillogenesis, we focus on those that have been suggested to be particularly relevant to collagen type I fibril formation during tendon development, including members of the collagen and small leucine-rich proteoglycan families, as well as other molecules, including scleraxis, cartilage oligomeric matrix protein, and cytoskeletal proteins.