Dickeyskaaning3073

AbstractMany small specialist herbivores utilize their food resources both for nutrition and as a structural refuge or resource. Trophic linkage cannot solely be inferred from physical association of herbivores with a potential food item, because herbivores may temporarily inhabit algae or plants on which they do not feed. Elysia papillosa, a small sacoglossan sea slug, consumes and sequesters chloroplasts from the siphonaceous, chlorophytic alga Penicillus capitatus; it also maintains moderate densities on this alga. Recently, E. papillosa was also infrequently found in association with the alga Penicillus lamourouxii, which displays density similar to that of P. capitatus. After collecting E. papillosa from each of the two algal species from a shallow-water site along the west central coast of Florida, we used DNA barcoding of the rbcL gene sequences in order to determine whether the slug was consuming both algal species. The molecular data indicated that E. papillosa consumed and sequestered chloroplasts from the same algal species from which they were collected. A laboratory feeding experiment tested whether algal diet (P. capitatus or P. lamourouxii) had an impact on slug growth rate as measured by change in body size (mm). After 3 weeks E. papillosa fed P. lamourouxii achieved a mean body length that was 1.5-2 times that recorded for slugs fed P. capitatus, but maximum growth depended on the original field host. Thus, while the highest densities of E. papillosa in the field occurred on P. capitatus, slugs grew much faster on P. lamourouxii in the laboratory. The observed association of E. papillosa with P. capitatus must be related to other factors, such as foraging efficiency, algal morphology, algal biochemistry, or algal suitability as a refuge.AbstractTrue mangroves are vascular plants (Tracheophyta) that evolved into inhabiting the mid and upper intertidal zone of tropical and subtropical soft-sediment coasts around the world. While several dozens of species are known from the Indo-West Pacific region, the Atlantic-East Pacific region is home to only a mere dozen of true mangrove species, most of which are rare. Mangrove trees can form dense monospecific or multispecies stands that provide numerous ecosystem services. Despite their eminent socioecological and socioeconomic relevance and the plethora of studies on mangroves, many details of the ecology of mangrove ecosystems remain unknown; and our knowledge about general ecological principles in mangrove ecosystems is scarce. For instance, the functional trait concept has hardly been applied to mangroves. Here we provide an inventory of 28 quantitative and 8 qualitative functional traits of true mangrove species and stipulate some insight into how these traits may drive ecosystem structure and pron the other hand, species of the genus Sonneratia exhibit low wood density and do not grow taller than 20 m. Some leaf traits of true mangroves are more like those of plants from drier environments, reflecting the perception that a saline environment creates physiological drought stress. Along the same line, most true mangrove species exhibit sclerophyllous leaf traits. The few major mangrove tree species of the Atlantic-East Pacific are as distinct from each other, with regard to some traits, as are the many mangrove species of the Indo-West Pacific. We hypothesize that this phenomenon explains the similarly high biomass of mangrove forests in both the species-rich Indo-West Pacific and the species-poor Atlantic-East Pacific.AbstractOceanic and coastal sampling programs have indicated extensive plastic pollution of marine habitats and revealed the need for understanding the scope and potential impacts of plastics on marine organisms. Sampling regimes for macroplastics (>5 mm) that can be visually collected for quantification and characterization in marine habitats provide valuable environmental data for the larger plastics. But less is known about the scope or potential impacts of small micron- and nano-sized bits of plastic that result from weathering of macroplastics and inputs of manufactured particles that could profoundly affect marine invertebrates, especially suspension feeders. Essential fundamental information about bivalve biology along with current research and reviews on microplastics, nanoplastics, and engineered nanoparticles were integrated to discuss how filter-feeding bivalves can serve as valuable bioindicators of plastic pollution. Bivalves can serve as important bioaccumulators of plastic particles and exhibit processing pathways that serve as biological sieves. Mesoplastics (1-5 mm) and large microplastics (>25 µm) will have a relatively short transit time (hours to days) and will primarily be concentrated in biodeposits (pseudofeces and feces). CDK activation Small microplastics ( less then 25 µm) and nanoplastics ( less then 1 µm) are more likely to be accumulated in digestive gland tissues and cells, and also hemocytes, and will have longer retention times. Lysosomes are a common target organelle for uptake and toxicity in both of these cell types. Therefore, bivalves can potentially act as biological sieves for characterizing relative environmental exposures and bioreactivity of microplastics and nanoplastics, based on critical particle capture and processing pathways. This framework highlights the importance of developing diagnostic approaches to characterize potential environmental risks associated with plastic particles as well as potential interactions with other anthropogenic pollutants.AbstractA combination of receptors, co-receptors, and secreted Wnt modulators form protein complexes at the cell surface that activate one or more of the three different Wnt signaling pathways (Wnt/β-catenin, Wnt/JNK, and Wnt/Ca2+). Two or more of these pathways are often active in the same cellular territories, forming Wnt signaling networks; however, the molecular mechanisms necessary to integrate information from these pathways in these situations are unclear in any in vivo model system. Recent studies have implicated two Wnt binding receptor tyrosine kinases, receptor tyrosine kinase-like orphan receptor (Ror) and related-to-receptor tyrosine kinase (Ryk), in the regulation of canonical and non-canonical Wnt signaling pathways, depending on the context; however, the spatiotemporal expression of these genes in relation to Wnt signaling components has not been well characterized in most deuterostome model systems. Here we use a combination of phylogenetic and spatiotemporal gene expression analyses to characterize Ror and Ryk orthologs in sea urchin embryos. Our phylogenetic analysis indicates that both ror1/2 and ryk originated as single genes from the metazoan ancestor. Expression analyses indicate that ror1/2 and ryk are expressed in the same domains of many Wnt ligands and Frizzled receptors essential for the specification and patterning of germ layers along the early anterior-posterior axis. In addition, both genes are co-expressed with Wnt signaling components in the gut, ventral ectoderm, and anterior neuroectoderm territories later in development. Together, our results indicate that Ror and Ryk have a complex evolutionary history and that their spatiotemporal expression suggests that they could contribute to the complexity of Wnt signaling in early sea urchin embryogenesis.AbstractHerbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Wounds can result in large amounts of tissue breaking away from macroalgae, amplifying the damage initially caused by herbivores. Herbivores that commonly wound macroalgae often occur over only a portion of a macroalga's lifespan or geographic range. However, we know little about the influence of these periodic or regional occurrences of herbivores on the large-scale seasonal and geographical patterns of macroalgal morphology. We used the intertidal kelp Egregia menziesii to investigate how the kelp's morphology and the prevalence of two prominent kelp-wounding herbivores (limpets and amphipods) changed over two seasons (spring and summer) and over the northern extent of the kelp's geographic range (six sites from central California to northern Washington). Wounds from limpets and amphipods often result in the kelp's fronds being pruned (intercalary meristem broken away), so we quantified kelp size (combined length of all fronds) and pruning (proportion of broken fronds). We found similar results in each season herbivores were most likely to occur on large, pruned kelp regardless of site; and limpets were the dominant herbivore at southern sites, while amphipods were dominant at northern sites. Despite the geographic shift in the dominant herbivore, kelp had similar levels of total herbivore prevalence (limpets and/or amphipods) and similar morphologies across sites. Our results suggest that large-scale geographic similarities in macroalgal wounding, despite regional variation in the herbivore community, can maintain similar macroalgal morphologies over large geographic areas.AbstractThe grass shrimp Palaemon pugio is an abundant and ecologically important species in estuarine habitats in the northwest Atlantic and is commonly used as an indicator species for environmental contamination, but little is known about its behavior. We examined aggression and dominance in P. pugio by using experimental arenas and groups of five shrimp that were observed an hour at a time for three days in the laboratory. Female shrimp showed high levels of initial aggression that quickly decreased over time, suggesting the formation of a dominance hierarchy. The dominance hierarchy between groups of females appeared linear, with shrimp at five distinct ranks in most replicates and higher-ranked individuals dominating lower-ranked ones. Dominance was significantly correlated with cheliped size but not body size, suggesting that larger chelipeds in female P. pugio may have evolved as a tool to establish dominance, perhaps to gain access to shelter in salt marshes, seagrass beds, or oyster reefs. Grass shrimp are preyed upon by a wide range of estuarine fish, and females are especially vulnerable; so securing access to shelter may provide a major selective advantage, with the dominance hierarchy evolving to save energy through a long-term reduction in fighting over resources.

India is experiencing a regional increase in cases of multidrug-resistant tuberculosis (MDR-TB). Given the complexity of MDR-TB diagnosis and care, we sought to address key knowledge gaps in MDR risk factors, care delays, and drivers of delay to help guide disease control.

From 1/2018-9/2019, we conducted interviews with adults registered with the National TB Elimination Program (NTEP) for MDR (n=128) and non-MDR-TB (n=269) treatment to quantitatively and qualitatively study care pathways. We collected treatment records and GeneXpert-TB/RIF diagnostic reports.

MDR-TB was associated with young age, and crowded residence. GeneXpert rifampicin resistance diversity was measured at 72.5% Probe E. Median time from symptom onset to diagnosis of MDR was 90 days vs. 60 days for non-MDR, Wilcoxon-P<0.01. Delay decreased by a median of 30 days among non-MDR patients with wider access to GeneXpert, Wilcoxon P=0.02. Pathways to care were complex with a median of 4 (3-5) and 3 (2-4) encounters for MDR and non-MDR respectively.