Summary
Y
bb−
is an rDNA-deficient chromosome of Drosophila that has often been used in magnification experiments to induce high-frequency reversion of
bobbed
(
bb
) chromosomes. We observed ...previously that
Y
bb−
causes ring chromosome loss even when the rings are
bb
+
, suggesting that
Y
bb−
induces magnifying sister chromatid exchanges in
bb
+
rings. Here we show that the
Y
bb-
chromosome causes low levels of bb magnification in
bb
+
flies. We refer to the ability of
Y
bb−
to bypass the rDNA deficiency requirement for magnification as ‘constitutive’ magnification. We have magnified the ribosomal genes on the
Y
bb−
chromosome and analysed the revertant chromosomes using genetic and molecular methods. We find that magnified
Y
bb−
chromosomes also exhibit constitutive magnifier activity. Molecular analysis shows that both type 1 and type 2 intron
+
ribosomal gene repeats are associated with magnified
Y
bb−
chromosomes. Type 2 introns have been described previously in the rDNA of both
X
and
Y
chromosomes. However, type 1 intervening sequences are thought to be present only in
X
, but not
Y
, ribosomal genes. Some of the
Y
bb−
type 1 insertions differ from those present in the rDNA of
X
chromosomes in that they contain an
Eco
Rl site, and some may be present in tandem arrays. The constitutive magnifier activity of
Y
bb−
may reside either in the structurally unusual ribosomal gene intervening sequences associated with the chromosome, or in the locus on
Y
L
that is required for magnification to occur.
There are concerns that recent climate change is altering the frequency and magnitude of river floods in an unprecedented way
. Historical studies have identified flood-rich periods in the past half ...millennium in various regions of Europe
. However, because of the low temporal resolution of existing datasets and the relatively low number of series, it has remained unclear whether Europe is currently in a flood-rich period from a long-term perspective. Here we analyse how recent decades compare with the flood history of Europe, using a new database composed of more than 100 high-resolution (sub-annual) historical flood series based on documentary evidence covering all major regions of Europe. We show that the past three decades were among the most flood-rich periods in Europe in the past 500 years, and that this period differs from other flood-rich periods in terms of its extent, air temperatures and flood seasonality. We identified nine flood-rich periods and associated regions. Among the periods richest in floods are 1560-1580 (western and central Europe), 1760-1800 (most of Europe), 1840-1870 (western and southern Europe) and 1990-2016 (western and central Europe). In most parts of Europe, previous flood-rich periods occurred during cooler-than-usual phases, but the current flood-rich period has been much warmer. Flood seasonality is also more pronounced in the recent period. For example, during previous flood and interflood periods, 41 per cent and 42 per cent of central European floods occurred in summer, respectively, compared with 55 per cent of floods in the recent period. The exceptional nature of the present-day flood-rich period calls for process-based tools for flood-risk assessment that capture the physical mechanisms involved, and management strategies that can incorporate the recent changes in risk.
Glutamate receptors at the postsynaptic side translate neurotransmitter release from presynapses into postsynaptic excitation. They play a role in many forms of synaptic plasticity, e.g., homeostatic ...scaling of the receptor field, activity-dependent synaptic plasticity and the induction of presynaptic homeostatic potentiation (PHP). The latter process has been extensively studied at
neuromuscular junctions (NMJs). The genetic removal of the glutamate receptor subunit IIA (GluRIIA) leads to an induction of PHP at the synapse. So far, mostly imprecise knockouts of the
gene have been utilized. Furthermore, mutated and tagged versions of GluRIIA have been examined in the past, but most of these constructs were not expressed under endogenous regulatory control or involved the mentioned imprecise
knockouts. We performed CRISPR/Cas9-assisted gene editing at the endogenous locus of
. This enabled the investigation of the endogenous expression pattern of GluRIIA using tagged constructs with an EGFP and an ALFA tag for super-resolution immunofluorescence imaging, including structured illumination microscopy (SIM) and
stochastic optical reconstruction microscopy (
STORM). All GluRIIA constructs exhibited full functionality and PHP could be induced by philanthotoxin at control levels. By applying hierarchical clustering algorithms to analyze the
STORM data, we detected postsynaptic receptor cluster areas of ~0.15 µm
. Consequently, our constructs are suitable for ultrastructural analyses of GluRIIA.
Glutamate receptors at the postsynaptic side translate neurotransmitter release from presynapses into postsynaptic excitation. They play a role in many forms of synaptic plasticity, e.g., homeostatic ...scaling of the receptor field, activity-dependent synaptic plasticity and the induction of presynaptic homeostatic potentiation (PHP). The latter process has been extensively studied at Drosophila melanogaster neuromuscular junctions (NMJs). The genetic removal of the glutamate receptor subunit IIA (GluRIIA) leads to an induction of PHP at the synapse. So far, mostly imprecise knockouts of the GluRIIA gene have been utilized. Furthermore, mutated and tagged versions of GluRIIA have been examined in the past, but most of these constructs were not expressed under endogenous regulatory control or involved the mentioned imprecise GluRIIA knockouts. We performed CRISPR/Cas9-assisted gene editing at the endogenous locus of GluRIIA. This enabled the investigation of the endogenous expression pattern of GluRIIA using tagged constructs with an EGFP and an ALFA tag for super-resolution immunofluorescence imaging, including structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM). All GluRIIA constructs exhibited full functionality and PHP could be induced by philanthotoxin at control levels. By applying hierarchical clustering algorithms to analyze the dSTORM data, we detected postsynaptic receptor cluster areas of ~0.15 µmsup.2. Consequently, our constructs are suitable for ultrastructural analyses of GluRIIA.
Arthropod-borne diseases remain a major health-threat for humans and animals worldwide. To estimate the distribution of pathogenic agents and especially Bartonella spp., we conducted tick microbiome ...analysis and determination of the infection status of wild animals, pets and pet owners in the state of Hesse, Germany.
In total, 189 engorged ticks collected from 163 animals were tested. Selected ticks were analyzed by next generation sequencing (NGS) and confirmatory PCRs, blood specimens of 48 wild animals were analyzed by PCR to confirm pathogen presence and sera of 54 dogs, one cat and 11 dog owners were analyzed by serology. Bartonella spp. were detected in 9.5% of all ticks and in the blood of 17 roe deer. Further data reveal the presence of the human and animal pathogenic species of genera in the family Spirochaetaceae (including Borrelia miyamotoi and Borrelia garinii), Bartonella spp. (mainly Bartonella schoenbuchensis), Rickettsia helvetica, Francisella tularensis and Anaplasma phagocytophilum in ticks. Co-infections with species of several genera were detected in nine ticks. One dog and five dog owners were seropositive for anti-Bartonella henselae-antibodies and one dog had antibodies against Rickettsia conorii.
This study provides a snapshot of pathogens circulating in ticks in central Germany. A broad range of tick-borne pathogens are present in ticks, and especially in wild animals, with possible implications for animal and human health. However, a low incidence of Bartonella spp., especially Bartonella henselae, was detected. The high number of various detected pathogens suggests that ticks might serve as an excellent sentinel to detect and monitor zoonotic human pathogens.
The deer ked (
) is distributed in Europe, North America, and Siberia and mainly infests cervids as roe deer, fallow deer, and moose. From a one health perspective, deer keds occasionally bite other ...animals or humans and are a potential vector for
. This bacterium belongs to a lineage of ruminant-associated
spp. and is suspected to cause dermatitis and febrile diseases in humans. In this study, we analyzed the microbiome from 130 deer keds collected from roe deer, fallow deer and humans in the federal states of Hesse, Baden-Wuerttemberg, and Brandenburg, Germany. Endosymbiontic
spp. and
spp. represented the biggest portion (~90%) of the microbiome. Most
spp. (
= 93) were confirmed to represent
. In deer keds collected from humans, no
spp. were detected. Furthermore,
spp. were present in four samples, one of those was confirmed to represent
. These data suggest that deer keds harbor only a very narrow spectrum of bacteria which are potentially pathogenic for animals of humans.
Objective
To compare the diagnostic performance of an artificial intelligence deep learning system with that of expert neuro‐ophthalmologists in classifying optic disc appearance.
Methods
The deep ...learning system was previously trained and validated on 14,341 ocular fundus photographs from 19 international centers. The performance of the system was evaluated on 800 new fundus photographs (400 normal optic discs, 201 papilledema disc edema from elevated intracranial pressure, 199 other optic disc abnormalities) and compared with that of 2 expert neuro‐ophthalmologists who independently reviewed the same randomly presented images without clinical information. Area under the receiver operating characteristic curve, accuracy, sensitivity, and specificity were calculated.
Results
The system correctly classified 678 of 800 (84.7%) photographs, compared with 675 of 800 (84.4%) for Expert 1 and 641 of 800 (80.1%) for Expert 2. The system yielded areas under the receiver operating characteristic curve of 0.97 (95% confidence interval CI = 0.96–0.98), 0.96 (95% CI = 0.94–0.97), and 0.89 (95% CI = 0.87–0.92) for the detection of normal discs, papilledema, and other disc abnormalities, respectively. The accuracy, sensitivity, and specificity of the system's classification of optic discs were similar to or better than the 2 experts. Intergrader agreement at the eye level was 0.71 (95% CI = 0.67–0.76) between Expert 1 and Expert 2, 0.72 (95% CI = 0.68–0.76) between the system and Expert 1, and 0.65 (95% CI = 0.61–0.70) between the system and Expert 2.
Interpretation
The performance of this deep learning system at classifying optic disc abnormalities was at least as good as 2 expert neuro‐ophthalmologists. Future prospective studies are needed to validate this system as a diagnostic aid in relevant clinical settings. ANN NEUROL 2020;88:785–795
To evaluate the performance of a deep learning system (DLS) in classifying the severity of papilledema associated with increased intracranial pressure on standard retinal fundus photographs.
A DLS ...was trained to automatically classify papilledema severity in 965 patients (2,103 mydriatic fundus photographs), representing a multiethnic cohort of patients with confirmed elevated intracranial pressure. Training was performed on 1,052 photographs with mild/moderate papilledema (MP) and 1,051 photographs with severe papilledema (SP) classified by a panel of experts. The performance of the DLS and that of 3 independent neuro-ophthalmologists were tested in 111 patients (214 photographs, 92 with MP and 122 with SP) by calculating the area under the receiver operating characteristics curve (AUC), accuracy, sensitivity, and specificity. Kappa agreement scores between the DLS and each of the 3 graders and among the 3 graders were calculated.
The DLS successfully discriminated between photographs of MP and SP, with an AUC of 0.93 (95% confidence interval CI 0.89-0.96) and an accuracy, sensitivity, and specificity of 87.9%, 91.8%, and 86.2%, respectively. This performance was comparable with that of the 3 neuro-ophthalmologists (84.1%, 91.8%, and 73.9%,
= 0.19,
= 1,
= 0.09, respectively). Misclassification by the DLS was mainly observed for moderate papilledema (Frisén grade 3). Agreement scores between the DLS and the neuro-ophthalmologists' evaluation was 0.62 (95% CI 0.57-0.68), whereas the intergrader agreement among the 3 neuro-ophthalmologists was 0.54 (95% CI 0.47-0.62).
Our DLS accurately classified the severity of papilledema on an independent set of mydriatic fundus photographs, achieving a comparable performance with that of independent neuro-ophthalmologists.
This study provides Class II evidence that a DLS using mydriatic retinal fundus photographs accurately classified the severity of papilledema associated in patients with a diagnosis of increased intracranial pressure.
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