55 research outputs found
A new selenosteid placoderm from the Late Devonian of the eastern Anti-Atlas (Morocco) with preserved body outline and its ecomorphology
Placoderms are an extinct group of early jawed vertebrates that play a key role in understanding the evolution of the gnathostome body plan, including the origin of novelties such as jaws, teeth, and pelvic fins. As placoderms have a poorly ossified axial skeleton, preservation of the mainly cartilaginous axial and fin elements is extremely rare, contrary to the heavily mineralized bones of the skull and thoracic armor. Therefore, the gross anatomy of the animals and body shape is only known from a few taxa, and reconstructions of the swimming function and ecology are speculative. Here, we describe articulated specimens preserving skull roofs, shoulder girdles, most fins, and body outlines of a newly derived arthrodire. Specimens of the selenosteid Amazichthys trinajsticae gen. et sp. nov. display a skull roof with reticular ornamentation and raised sensory lines like Driscollaspis, a median dorsal plate with a unique sharp posterior depression, the pelvic girdle, the proportions and shape of the pectoral, dorsal, and caudal fins as well as a laterally enlarged region resembling the lateral keel of a few modern sharks and bony fishes. Our new phylogenetic analyses support the monophyly of the selenosteid family and place the new genus in a clade with Melanosteus, Enseosteus, Walterosteus, and Draconichthys. The shape of its body and heterocercal caudal fin in combination with the pronounced 'lateral keel' suggest Amazichthys trinajsticae was an active macropelagic swimmer capable of reaching high swimming speeds
A new selenosteid placoderm from the Late Devonian of the eastern Anti-Atlas (Morocco) with preserved body outline and its ecomorphology
Placoderms are an extinct group of early jawed vertebrates that play a key role in understanding the evolution of the gnathostome body plan, including the origin of novelties such as jaws, teeth, and pelvic fins. As placoderms have a poorly ossified axial skeleton, preservation of the mainly cartilaginous axial and fin elements is extremely rare, contrary to the heavily mineralized bones of the skull and thoracic armor. Therefore, the gross anatomy of the animals and body shape is only known from a few taxa, and reconstructions of the swimming function and ecology are speculative. Here, we describe articulated specimens preserving skull roofs, shoulder girdles, most fins, and body outlines of a newly derived arthrodire. Specimens of the selenosteid Amazichthys trinajsticae gen. et sp. nov. display a skull roof with reticular ornamentation and raised sensory lines like Driscollaspis, a median dorsal plate with a unique sharp posterior depression, the pelvic girdle, the proportions and shape of the pectoral, dorsal, and caudal fins as well as a laterally enlarged region resembling the lateral keel of a few modern sharks and bony fishes. Our new phylogenetic analyses support the monophyly of the selenosteid family and place the new genus in a clade with Melanosteus, Enseosteus, Walterosteus, and Draconichthys. The shape of its body and heterocercal caudal fin in combination with the pronounced “lateral keel” suggest Amazichthys trinajsticae was an active macropelagic swimmer capable of reaching high swimming speeds
Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data
OBJECTIVE: A retrospective analysis of laboratory data to investigate the isolation of Staphylococcus aureus from the oral cavity and facial area in specimens submitted to a regional diagnostic oral microbiology laboratory. METHODS: A hand search of laboratory records for a three-year period (1998-2000) was performed for specimens submitted to the regional diagnostic oral microbiology laboratory based at Glasgow Dental Hospital and School. Data were collected from forms where S. aureus was isolated. These data included demographics, referral source, specimen type, methicillin susceptibility and clinical details. RESULTS: For the period 1998-2000, there were 5,005 specimens submitted to the laboratory. S. aureus was isolated from 1,017 specimens, of which 967 (95%) were sensitive to methicillin (MSSA) and 50 (5%) were resistant to methicillin (MRSA). The 1,017 specimens were provided from 615 patients. MRSA was isolated from 37 (6%) of patients. There was an increasing incidence of S. aureus with age, particularly in the greater than 70 years age group. The most common specimen from which MSSA was isolated was an oral rinse (38%) whilst for MRSA isolates this was a tongue swab (28%). The clinical condition most commonly reported for MSSA isolates was angular cheilitis (22%). Erythema, swelling, pain or burning of the oral mucosa was the clinical condition most commonly reported for MRSA isolates (16%). Patients from whom the MSSA isolates were recovered were most commonly (55%) seen in the oral medicine clinic at the dental hospital, whilst patients with MRSA were more commonly seen in primary care settings such as nursing homes, hospices and general dental practice (51%). CONCLUSION: In line with more recent surveys, this retrospective study suggests that S. aureus may be a more frequent isolate from the oral cavity than hitherto suspected. A small proportion of the S. aureus isolates were MRSA. There were insufficient data available to determine whether the S. aureus isolates were colonising or infecting the oral cavity. However, the role of S. aureus in several diseases of the oral mucosa merits further investigation
Climate change adaptation among female-led micro, small, and medium enterprises in semiarid areas: a case study from Kenya
This chapter contributes to the literature on private sector adaptation by empirically exploring how female-led micro, small, and medium enterprise (MSMEs) in Kenya’s semiarid lands (SALs) experience and respond to climate risk. The chapter argues that strong sociocultural orientations around gender roles and resource use and access not only confine female-led MSMEs to sectors that experience higher exposure to climate risk – most notably agriculture – but also trigger more pronounced barriers to building resilience within their businesses, including reduced access to land, capital, markets, new technology, and educational opportunities. Faced by these barriers, female entrepreneurs may pursue unsustainable forms of coping, as part of which business activity is scaled back through reduced profits, loss of business, and the sale of valuable business assets. Such strategies may help enterprises to cope in the short term but may undermine longer-term MSME adaptive capacity. Social networks, such as women’s groups and table banking initiatives, appear to be crucial adaptation tools. Additionally, a strong dependency exists between household resilience and business resilience, implying that building resilience at the household level could support adaptive capacity among female-led MSMEs. Supporting the adaptive capacity of women in business should be a policy priority
Characterization of the Oral Fungal Microbiome (Mycobiome) in Healthy Individuals
The oral microbiome–organisms residing in the oral cavity and their collective genome–are critical components of health and disease. The fungal component of the oral microbiota has not been characterized. In this study, we used a novel multitag pyrosequencing approach to characterize fungi present in the oral cavity of 20 healthy individuals, using the pan-fungal internal transcribed spacer (ITS) primers. Our results revealed the “basal” oral mycobiome profile of the enrolled individuals, and showed that across all the samples studied, the oral cavity contained 74 culturable and 11 non-culturable fungal genera. Among these genera, 39 were present in only one person, 16 genera were present in two participants, and 5 genera were present in three people, while 15 genera (including non-culturable organisms) were present in ≥4 (20%) participants. Candida species were the most frequent (isolated from 75% of participants), followed by Cladosporium (65%), Aureobasidium, Saccharomycetales (50% for both), Aspergillus (35%), Fusarium (30%), and Cryptococcus (20%). Four of these predominant genera are known to be pathogenic in humans. The low-abundance genera may represent environmental fungi present in the oral cavity and could simply be spores inhaled from the air or material ingested with food. Among the culturable genera, 61 were represented by one species each, while 13 genera comprised between 2 and 6 different species; the total number of species identified were 101. The number of species in the oral cavity of each individual ranged between 9 and 23. Principal component (PCO) analysis of the obtained data set followed by sample clustering and UniFrac analysis revealed that White males and Asian males clustered differently from each other, whereas both Asian and White females clustered together. This is the first study that identified the “basal mycobiome” of healthy individuals, and provides the basis for a detailed characterization of the oral mycobiome in health and disease
Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus)
BACKGROUND: Koalas (Phascolarctos cinereus), an iconic Australian marsupial, are being heavily impacted by the spread of Chlamydia pecorum, an obligate intracellular bacterial pathogen. Koalas vary in their response to this pathogen, with some showing no symptoms, while others suffer severe symptoms leading to infertility, blindness or death. Little is known about the pathology of this disease and the immune response against it in this host. Studies have demonstrated that natural killer (NK) cells, key components of the innate immune system, are involved in the immune response to chlamydial infections in humans. These cells can directly lyse cells infected by intracellular pathogens and their ability to recognise these infected cells is mediated through NK receptors on their surface. These are encoded in two regions of the genome, the leukocyte receptor complex (LRC) and the natural killer complex (NKC). These two families evolve rapidly and different repertoires of genes, which have evolved by gene duplication, are seen in different species. METHODS: In this study we aimed to characterise genes belonging to the NK receptor clusters in the koala by searching available koala transcriptomes using a combination of search methods. We developed a qPCR assay to quantify relative expression of four genes, two encoded within the NK receptor cluster (CLEC1B, CLEC4E) and two known to play a role in NK response to Chalmydia in humans (NCR3, PRF1). RESULTS: We found that the NK receptor repertoire of the koala closely resembles that of the Tasmanian devil, with minimal genes in the NKC, but with lineage specific expansions in the LRC. Additional genes important for NK cell activity, NCR3 and PRF1, were also identified and characterised. In a preliminary study to investigate whether these genes are involved in the koala immune response to infection by its chlamydial pathogen, C. pecorum, we investigated the expression of four genes in koalas with active chlamydia infection, those with past infection and those without infection using qPCR. This analysis revealed that one of these four, CLEC4E, may be upregulated in response to chlamydia infection. CONCLUSION: We have characterised genes of the NKC and LRC in koalas and have discovered evidence that one of these genes may be upregulated in koalas with chlamydia, suggesting that these receptors may play a role in the immune response of koalas to chlamydia infection
Emerging infectious disease implications of invasive mammalian species : the greater white-toothed shrew (Crocidura russula) is associated with a novel serovar of pathogenic Leptospira in Ireland
The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira
Should patients with hip joint prosthesis receive antibiotic prophylaxis before dental treatment?
The safety committee of the American Academy of Orthopedic Surgeons (AAOS) recommended in 2009 that clinicians should consider antibiotic prophylaxis for all patients with total joint replacement before any invasive procedure that may cause bacteremia. This has aroused confusion and anger among dentists asking for the evidence. The present review deals with different aspects of the rationale for this recommendation giving attention to views both in favor of and against it
Proprioceptive performance of bilateral upper and lower limb joints: side-general and site-specific effects
Superiority of the left upper limb in proprioception tasks performed by right-handed individuals has been attributed to better utilization of proprioceptive information by a non-preferred arm/hemisphere system. However, it is undetermined whether this holds for multiple upper and lower limb joints. Accordingly, the present study tested active movement proprioception at four pairs of upper and lower limb joints, after selecting twelve participants with both strong right arm and right leg preference. A battery of versions of the active movement extent discrimination apparatus were employed to generate the stimuli for movements of different extents at the ankle, knee, shoulder and fingers on the right and left sides of the body, and discrimination scores were derived from participants’ responses. Proprioceptive performance on the non-preferred left side was significantly better than the preferred right side at all four joints tested (overall F(1, 11) = 36.36, p < 0.001, partial η(2) = 0.77). In the 8 × 8 matrix formed by all joints, only correlations between the proprioceptive accuracy scores for the right and left sides at the same joint were significant (ankles 0.93, knees 0.89, shoulders 0.87, fingers 0.91, p ≤ 0.001; all others r ≤ 0.40, p ≥ 0.20). The results point to both a side-general effect and a site-specific effect in the integration of proprioceptive information during active movement tasks, whereby the non-preferred limb/hemisphere system is specialized in the utilization of the best proprioceptive sources available at each specific joint, but the combination of sources employed differs between body sites
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