New species discoveries or the rediscovery of species once considered extinct or extirpated is good news, and yet prospects for long‐term survival may be bleak if remnant populations are small and ...isolated. Because (re)discovered species are commonly rare or cryptic, data to inform appropriate conservation actions are usually sparse. We demonstrate how to make the most of available data, using the recent rediscovery in Ghana of sitatunga Tragelaphus spekei as an illustrative case study. Sitatunga were thought extinct in Ghana for over 50 years, but were ‘rediscovered’ by science in Avu Lagoon in 1998. Little is known about this species, especially West African populations, given its cryptic nature and inaccessible wetland habitat. Our approach to maximizing insights given limited data first paired observations of occurrence with landscape characteristics derived from open‐access remote sensing data, creating the first ever habitat suitability model for sitatunga. This model then served to: (1) elucidate habitat preferences; (2) assess possible existence and connectivity of remnant populations elsewhere in Ghana; and (3) estimate maximum total and effective population size. Moreover, the timing of occurrence sightings provided insights into behavior. Sitatunga sightings were rare, heavily male‐biased and mostly occurred between 6 pm and 6 am. Suitable habitat was limited, suggesting that habitat in and near Avu Lagoon is insufficient to ensure long‐term population viability, and the existence of other, connected populations in Ghana is improbable. Without continued protection, and possibly additional interventions to augment population numbers or gene flow, the sitatunga in Avu Lagoon will likely go extinct. Our case study demonstrates the conservation challenges associated with the rediscovery of relict populations, and the utility of applying tools such as habitat suitability models to sparse data. Moreover, our research stresses the need to implement immediate conservation action upon species (re)discoveries to prevent (regional) extinction.
Species (re)discoveries often involve small, isolated populations that require urgent conservation interventions despite limited data. We use a case study of the recent rediscovery in Ghana of sitatunga Tragelaphus spekei, a cryptic wetland antelope, to illustrate how even sparse data can yield considerable, conservation‐relevant insights. Our approach first paired observations of occurrence with landscape characteristics derived from open‐access remote sensing and map data. The resulting habitat suitability model, a first for sitatunga, then served to: (1) elucidate habitat preferences; (2) assess possible existence and connectivity of remnant populations elsewhere in Ghana; and (3) estimate maximum total and effective population size. Our results demonstrate the conservation challenges associated with the rediscovery of relict populations, and the utility of applying tools such as habitat suitability models to sparse data. Moreover, our research stresses the need to implement immediate conservation action upon species (re)discoveries to prevent (regional) extinction.
Topical nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, alone or in combination, have historically been used off label in the US to prevent and treat postoperative cystoid macular ...edema (CME). This literature review presents available data on the use of bromfenac 0.07% or 0.09% to prevent and treat CME following cataract surgery. Bromfenac is an NSAID approved to treat postoperative inflammation and reduce ocular pain following cataract surgery. Few cases of clinical CME were observed with bromfenac use in a total of 19 reviewed studies. There were no significant differences in CME incidence between bromfenac and corticosteroid-treated patients or between bromfenac- and bromfenac plus corticosteroid-treated patients. Bromfenac demonstrated comparable efficacy to other NSAIDs in preventing CME. Compared with corticosteroids, bromfenac alone or plus a corticosteroid showed similar or better efficacy in minimizing changes in retinal thickness and macular volume. In diabetic cataract surgery patients, bromfenac was comparable or superior to corticosteroids for minimizing changes in retinal thickness; also, combination therapy with bromfenac and corticosteroids may be associated with smaller changes in foveal thickness, macular thickness, and macular volume versus monotherapy with either treatment alone in this patient population. In two randomized, double-masked, placebo-controlled clinical trials with bromfenac 0.07%, CME was reported as an adverse event in 0.5% and 1.5% of patients receiving bromfenac and placebo, respectively. In an analysis of four placebo-controlled trials with bromfenac 0.09%, macular edema was reported in 0.7% and 1.4% of patients receiving bromfenac and placebo, respectively. When evaluated as treatment for acute or chronic CME, bromfenac was associated with improvement in visual acuity and reduction in retinal thickness, but few studies are available. Overall, published data suggest that bromfenac is safe and effective when used to prevent or treat CME. Large-scale placebo-controlled trials and greater standardization of CME measures are needed to establish optimal bromfenac regimens for the prophylaxis and treatment of CME following cataract surgery.
We have characterized platelet-derived growth factor (PDGF) C, a novel growth factor belonging to the PDGF family. PDGF-C is a multidomain protein with the N-terminal region homologous to the ...extracellular CUB domain of neuropilin-1, and the C-terminal region consists of a growth factor domain (GFD) with homology to vascular endothelial growth factor (25%) and PDGF A-chain (23%). A serum-sensitive cleavage site between the two domains allows release of the GFD from the CUB domain. Competition binding and immunoprecipitation studies on cells bearing both PDGF α and β receptors reveal a high affinity binding of recombinant GFD (PDGF-CC) to PDGF receptor-α homodimers and PDGF receptor-α/β heterodimers. PDGF-CC exhibits greater mitogenic potency than PDGF-AA and comparable or greater mitogenic activity than PDGF-AB and PDGF-BB on several mesenchymal cell types. Analysis of PDGF-CC in vivo in a diabetic mouse model of delayed wound healing showed that PDGF-CC significantly enhanced repair of a full-thickness skin excision. Together, these studies describe a third member of the PDGF family (PDGF-C) as a potent mitogen for cells of mesenchymal origin inin vitro and in vivo systems with a binding pattern similar to PDGF-AB.
Quantum molecular dynamics (QMD) simulations are used to calculate the equation of state, structure, and transport properties of liquid gallium along the principal shock Hugoniot. The calculated ...Hugoniot is in very good agreement with experimental data up to a pressure of 150 GPa as well as with our earlier classical molecular dynamics calculations using a modified embedded atom method (MEAM) potential. The self-diffusion and viscosity calculated using QMD agree with experimental measurements better than the MEAM results, which we attribute to capturing the complexity of the electronic structure at elevated temperatures. Calculations of the DC conductivity were performed around the Hugoniot. Above a density of 7.5 g/cm(3), the temperature increases rapidly along the Hugoniot, and the optical conductivity decreases, indicating simple liquid metal behavior.
The regional wall motion impairment and predisposition to arrhythmias in human ventricular hibernation may plausibly result from abnormal intercellular propagation of the depolarizing wave front. ...This study investigated the hypothesis that altered patterns of expression of connexin43, the principal gap junctional protein responsible for passive conduction of the cardiac action potential, contribute to the pathogenesis of hibernation.
Patients with poor ventricular function and severe coronary artery disease underwent thallium scanning and MRI to predict regions of normally perfused, reversibly ischemic, or hibernating myocardium. Twenty-one patients went on to coronary artery bypass graft surgery, during which biopsies representative of each of the above classes were taken. Hibernation was confirmed by improvement in segmental wall motion at reassessment 6 months after surgery. Connexin43 was studied by quantitative immunoconfocal laser scanning microscopy and PC image software. Analysis of en face projection views of intercalated disks revealed a significant reduction in relative connexin43 content per unit area in reversibly ischemic (76.7+/-34.6%, P<.001) and hibernating (67.4+/-24.3%, P<.001) tissue compared with normal (100+/-30.3%); ANOVA P<.001. The hibernating regions were further characterized by loss of the larger gap junctions normally seen at the disk periphery, reflected by a significant reduction in mean junctional plaque size in the hibernating tissues (69.5+/-20.8%) compared with reversibly ischemic (87.4+/-31.2%, P=.012) and normal (100+/-31.5%, P<.001) segments; ANOVA P<.001.
These results indicate progressive reduction and disruption of connexin43 gap junctions in reversible ischemia and hibernation. Abnormal impulse propagation resulting from such changes may contribute to the electromechanical dysfunction associated with hibernation.
Interleukin (IL)-13, a cytokine released by T lymphocytes during immediate hypersensitivity responses, is a central mediator of asthma. Because IL-13 induces phenotypic features of asthma in mice ...deficient in T and B lymphocytes, it is likely that this cytokine contributes to the development of asthma by acting directly on resident airway cells. To analyze the global effects of IL-13 on gene expression in airway cells that could contribute to the phenotypic features of asthma, we used Genechip HuGene FL arrays (Affymetrix, Santa Clara, CA) that contain probes for approximately 6,500 human genes. Despite activating a common signaling pathway, IL-13 induced dramatically different patterns of gene expression in primary cultures of airway epithelial cells, airway smooth muscle cells, and lung fibroblasts, with little overlap among cell types. The most prominent effects of IL-13 were on airway smooth muscle, but several genes induced in airway epithelial cells and fibroblasts are also candidates that may contribute to phenotypic features of asthma. These results suggest that the in vivo response to IL-13 in the airways likely results from a combination of distinct effects on each of several resident airway cell types.
Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of ...these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwinia pyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely related to Pantoea ananatis but represented a divergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omnipresent in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea.
Growth and propagation of fish-infecting microsporidians within cell culture has been more difficult to achieve than for insect- and human-infecting microsporidians. Fish microsporidia tend to elicit ...xenoma development rather than diffuse growth in vivo, and this process likely increases host specificity. We present evidence that the fish microsporidian, Loma salmonae, has the capacity to develop xenomas within a rainbow trout gill epithelial cell line (RTG-1). Spore numbers increased over a 4 weeks period within cell culture flasks. Xenoma-like structures were observed using phase contrast microscopy, and then confirmed using transmission electron microscopy. Optimization of the L. salmonae-RTG-1 cell model has important implications in elucidating the process of xenoma development induced by microsporidian parasites.
Abstract
Phonemic restoration—perceiving speech sounds that are actually missing—is a fundamental perceptual process that ‘repairs’ interrupted spoken messages during noisy everyday listening. As a ...dynamic, integrative process, phonemic restoration is potentially affected by neurodegenerative pathologies, but this has not been clarified. Here, we studied this phenomenon in 5 patients with typical Alzheimer’s disease and 4 patients with semantic dementia, relative to 22 age-matched healthy controls. Participants heard isolated sounds, spoken real words and pseudowords in which noise bursts either overlaid a consonant or replaced it; a tendency to hear replaced (missing) speech sounds as present signified phonemic restoration. All groups perceived isolated noises normally and showed phonemic restoration of real words, most marked in Alzheimer’s patients. For pseudowords, healthy controls showed no phonemic restoration, while Alzheimer’s patients showed marked suppression of phonemic restoration and patients with semantic dementia contrastingly showed phonemic restoration comparable to real words. Our findings provide the first evidence that phonemic restoration is preserved or even enhanced in neurodegenerative diseases, with distinct syndromic profiles that may reflect the relative integrity of bottom-up phonological representation and top-down lexical disambiguation mechanisms in different diseases. This work has theoretical implications for predictive coding models of language and neurodegenerative disease and for understanding cognitive ‘repair’ processes in dementia. Future research should expand on these preliminary observations with larger cohorts.
Jiang et al. studied phonemic restoration of words in Alzheimer and semantic dementia patients versus healthy controls. All groups showed phonemic restoration of real words. Versus controls, phonemic restoration of pseudowords was enhanced in semantic dementia and reduced in Alzheimer’s disease. Findings suggest a retained perceptual repair mechanism in dementia.
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Graphical Abstract
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