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Kostbare Manschettenknöpfe : von Pablo Picasso bis James Bond = Precious cufflinks : from Pablo Picasso to James Bond
PRECIOUS METAL, PRECIOUS STONES & JEWELLERY: ARTWORKS & DESIGN. They are one of the highlights of the world of jewellery. From the rectangular to the round and rounded: Cufflinks are timeless eye catchers. Those who adorn their shirt sleeves with such works of art can be sure to attract attention. This knowledgeable publication introduces readers to the world of cufflinks, tracing their story and showing rare designs. Cufflinks are among the few pieces of jewellery worn by men and, like wristwatches, are an essential part of mens fashion. The first cufflinks appeared as early as the seventeenth century, but they did not come into common usage until the late eighteenth century as their development was closely connected to that of mens shirts. Nowadays cufflinks are little artworks that allow men to express their own personality in an understated way. Their design and the materials from which they are made can speak volumes about the wearers preferences, hobbies and profession.
Book
Heritable CRISPR/Cas9-Mediated Genome Editing in the Yellow Fever Mosquito, Aedes aegypti
In vivo targeted gene disruption is a powerful tool to study gene function. Thus far, two tools for genome editing in Aedes aegypti have been applied, zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN). As a promising alternative to ZFN and TALEN, which are difficult to produce and validate using standard molecular biological techniques, the clustered regularly interspaced short palindromic repeats/CRISPR-associated sequence 9 (CRISPR/Cas9) system has recently been discovered as a \"do-it-yourself\" genome editing tool. Here, we describe the use of CRISPR/Cas9 in the mosquito vector, Aedes aegypti. In a transgenic mosquito line expressing both Dsred and enhanced cyan fluorescent protein (ECFP) from the eye tissue-specific 3xP3 promoter in separated but tightly linked expression cassettes, we targeted the ECFP nucleotide sequence for disruption. When supplying the Cas9 enzyme and two sgRNAs targeting different regions of the ECFP gene as in vitro transcribed mRNAs for germline transformation, we recovered four different G1 pools (5.5% knockout efficiency) where individuals still expressed DsRed but no longer ECFP. PCR amplification, cloning, and sequencing of PCR amplicons revealed indels in the ECFP target gene ranging from 2-27 nucleotides. These results show for the first time that CRISPR/Cas9 mediated gene editing is achievable in Ae. aegypti, paving the way for further functional genomics related studies in this mosquito species.
Journal Article
On good management : the corporate lifecycle : an essay and interviews with Franz Fehrenbach, Jèurgen Hambrecht, Wolfgang Reitzle and Alexander Rittweger
Roland Berger Chairman Burkhard Schwenker analyzes the challenges facing managers today and explores what these mean for good management. Corporate management, he argues, must once again become more direct, more personal, more entrepreneurial. The thoughts of the experienced consultant himself are complemented by very personal interviews with Franz Fehrenbach, Jèurgen Hambrecht, Wolfgang Reitzle and Alexander Rittweger, conducted by journalist Mario Mèuller-Dofel. How, then, can we come closer to the ideal of good management? Schwenker outlines an agenda calling for action in six specific areas: change the education provided by universities, reinforce on-the-job development and training, improve corporate recruiting policies, strike a balance between management and leadership, be an advertisement for good management and perhaps the greatest challenge of all do not tolerate compromise!
Book
Performance of two low-threshold population replacement gene drives in cage populations of the yellow fever mosquito, Aedes aegypti
Aedes aegypti is the predominant vector for arboviruses including dengue, Zika, and chikungunya viruses, which infect over 100 million people annually. Mosquito population replacement in which arbovirus-susceptible mosquitoes in the field are replaced by laboratory-engineered refractory mosquitoes represents a novel genetic control measure to interrupt arboviral disease cycles. For this approach, the engineered mosquitoes need to harbor two genetic components: an antiviral effector construct which is linked to a gene drive (GD). We tested the performance of two single-locus CRISPR/Cas9 based GD for Ae. aegypti population replacement in small cage populations for up to 16 generations. Starting from a low release threshold of 1:9 GD bearing males to wild-type males, we observed two GD constructs in which Cas9 was expressed from two different germline promoters, nanos and zpg , to increase in frequency in all cage populations. By G16, an average of 72% and 82% of individuals from the zpg -GD and nanos -GD populations, respectively, harbored at least one GD copy with corresponding increases in allele frequencies. This indicated that the two single-locus, CRISPR/Cas9-based homing GD exhibited continuous super-Mendelian inheritance in populations of Ae. aegypti . Gene drive blocking indel (GDBI, a.k.a. “resistant alleles”) frequency was measured for each discrete generation in pooled samples from the six populations harboring GD. We found that populations with Cas9 expression under control of the nanos -promoter accumulated GDBI at more than twice the rate of those populations harboring the zpg -promoter driven GD. Based on preexisting data sets for homing and GDBI frequencies in addition to the cage trial observations, the relative contributions of sex-specific homing rates, maternal Cas9 deposition and potential fitness effects were modeled in MGDrivE for both GD, further explaining their divergent performance. Our study demonstrates the feasibility of low-threshold, single-locus CRISPR/Cas9 based GD for Ae. aegypti population replacement.
Journal Article
Chikungunya virus dissemination from the midgut of Aedes aegypti is associated with temporal basal lamina degradation during bloodmeal digestion
In the mosquito, the midgut epithelium is the initial tissue to become infected with an arthropod-borne virus (arbovirus) that has been acquired from a vertebrate host along with a viremic bloodmeal. Following its replication in midgut epithelial cells, the virus needs to exit the midgut and infect secondary tissues including the salivary glands before it can be transmitted to another vertebrate host. The viral exit mechanism from the midgut, the midgut escape barrier (MEB), is poorly understood although it is an important determinant of mosquito vector competence for arboviruses. Using chikungunya virus (CHIKV) as a model in Aedes aegypti, we demonstrate that the basal lamina (BL) of the extracellular matrix (ECM) surrounding the midgut constitutes a potential barrier for the virus. The BL, predominantly consisting of collagen IV and laminin, becomes permissive during bloodmeal digestion in the midgut lumen. Bloodmeal digestion, BL permissiveness, and CHIKV dissemination are coincident with increased collagenase activity, diminished collagen IV abundance, and BL shredding in the midgut between 24-32 h post-bloodmeal. This indicates that there may be a window-of-opportunity during which the MEB in Ae. aegypti becomes permissive for CHIKV. Matrix metalloproteinases (MMPs) are the principal extracellular endopeptidases responsible for the degradation/remodeling of the ECM including the BL. We focused on Ae. aegypti (Ae)MMP1, which is expressed in midgut epithelial cells, is inducible upon bloodfeeding, and shows collagenase (gelatinase) activity. However, attempts to inhibit AeMMP activity in general or specifically that of AeMMP1 did not seem to affect its function nor produce an altered midgut escape phenotype. As an alternative, we silenced and overexpressed the Ae. aegypti tissue inhibitor of metalloproteinases (AeTIMP) in the mosquito midgut. AeTIMP was highly upregulated in the midgut during bloodmeal digestion and was able to inhibit MMP activity in vitro. Bloodmeal-inducible, midgut-specific overexpression of AeTIMP or its expression via a recombinant CHIKV significantly increased midgut dissemination rates of the virus. Possibly, AeTIMP overexpression affected BL degradation and/or restoration thereby increasing the midgut dissemination efficiency of the virus.
Journal Article
African and Asian strains of Zika virus differ in their ability to infect and lyse primitive human placental trophoblast
Zika virus (ZIKV) drew worldwide attention when a recent epidemic was linked to fetal microcephaly. Here we used human embryonic stem cell derived trophoblasts as a model for primitive placental trophoblast to test the hypothesis that there are differences in how the two genetically distinct ZIKV lineages, African (AF) and Asian (AS), target the human placenta. Upon infection with three AF (ib-H30656, SEN/1984/41525-DAK, and MR-766) and three AS (FSS13025, MexI-44, and PANcdc259249) ZIKV strains, we observed that severe placental cell lysis was only induced after infection with AF strains, while viral replication rates remained similar between both lineages. Differences in cytopathic effects (CPE) were not observed in Vero cells, indicating that the AF strains were not inherently superior at cell lysis. Taken together, we propose that infection with AF strains of ZIKV early in pregnancy would likely result in pregnancy loss, rather than allow further fetal development with accompanying brain damage. Our results also suggest that the long term laboratory-adapted MR-766 strain does not behave aberrantly in cell culture relative to other AF lineage strains.
Journal Article
Starvation at the larval stage increases the vector competence of Aedes aegypti females for Zika virus
Aedes aegypti is the primary vector of Zika virus (ZIKV), a flavivirus which typically presents itself as febrile-like symptoms in humans but can also cause neurological and pregnancy complications. The transmission cycle of mosquito-borne arboviruses such as ZIKV requires that various key tissues in the female mosquito get productively infected with the virus before the mosquito can transmit the virus to another vertebrate host. Following ingestion of a viremic blood-meal from a vertebrate, ZIKV initially infects the midgut epithelium before exiting the midgut after blood-meal digestion to disseminate to secondary tissues including the salivary glands. Here we investigated whether smaller Ae . aegypti females resulting from food deprivation as larvae exhibited an altered vector competence for blood-meal acquired ZIKV relative to larger mosquitoes. Midguts from small ‘Starve’ and large ‘Control’ Ae . aegypti were dissected to visualize by transmission electron microscopy (TEM) the midgut basal lamina (BL) as physical evidence for the midgut escape barrier showing Starve mosquitoes with a significantly thinner midgut BL than Control mosquitoes at two timepoints. ZIKV replication was inhibited in Starve mosquitoes following intrathoracic injection of virus, however, Starve mosquitoes exhibited a significantly higher midgut escape and population dissemination rate at 9 days post-infection (dpi) via blood-meal, with more virus present in saliva and head tissue than Control by 10 dpi and 14 dpi, respectively. These results indicate that Ae . aegypti developing under stressful conditions potentially exhibit higher midgut infection and dissemination rates for ZIKV as adults, Thus, variation in food intake as larvae is potentially a source for variable vector competence levels of the emerged adults for the virus.
Journal Article
Cellular diversity and gene expression profiles in the male and female brain of Aedes aegypti
Background
Aedes aegypti
is a medically-important mosquito vector that transmits arboviruses including yellow fever, dengue, chikungunya, and Zika viruses to humans. The mosquito exhibits typical sexually dimorphic behaviors such as courtship, mating, host seeking, bloodfeeding, and oviposition. All these behaviors are mainly regulated by the brain; however, little is known about the function and neuron composition of the mosquito brain. In this study, we generated an initial atlas of the adult male and female brain of
Ae. aegypti
using 10xGenomics based single-nucleus RNA sequencing.
Results
We identified 35 brain cell clusters in male and female brains, and 15 of those clusters were assigned to known cell types. Identified cell types include glia (astrocytes), Kenyon cells, (ventral) projection neurons, monoaminergic neurons, medulla neurons, and proximal medulla neurons. In addition, the cell type compositions of male and female brains were compared to each other showing that they were quantitatively distinct, as 17 out of 35 cell clusters varied significantly in their cell type proportions. Overall, the transcriptomes from each cell cluster looked very similar between the male and female brain as only up to 25 genes were differentially expressed in these clusters. The sex determination factor
Nix
was highly expressed in neurons and glia of the male brain, whereas
doublesex
(
dsx
) was expressed in all neuron and glia cell clusters of the male and female brain.
Conclusions
An initial cell atlas of the brain of the mosquito
Ae. aegypti
has been generated showing that the cellular compositions of the male and female brains of this hematophagous insect differ significantly from each other. Although some of the rare brain cell types have not been detected in our single biological replicate, this study provides an important basis for the further development of a complete brain cell atlas as well as a better understanding of the neurobiology of the brains of male and female mosquitoes and their sexually dimorphic behaviors.
Journal Article
The midgut transcriptome of Aedes aegypti fed with saline or protein meals containing chikungunya virus reveals genes potentially involved in viral midgut escape
Background
The mosquito
Aedes aegypti
is the primary vector for medically important arthropod-borne viruses, including chikungunya virus (CHIKV). Following oral acquisition, an arbovirus has to persistently infect several organs in the mosquito before becoming transmissible to another vertebrate host. A major obstacle an arbovirus has to overcome during its infection cycle inside the mosquito is the midgut escape barrier, representing the exit mechanism arboviruses utilize when disseminating from the midgut. To understand the transcriptomic basis of midgut escape and to reveal genes involved in the process, we conducted a comparative transcriptomic analysis of midgut samples from mosquitoes which had received a saline meal (SM) or a protein meal (PM) (not) containing CHIKV.
Results
CHIKV which was orally acquired by a mosquito along with a SM or PM productively infected the midgut epithelium and disseminated to secondary tissues. A total of 27 RNA-Seq libraries from midguts of mosquitoes that had received PM or SM (not) containing CHIKV at 1 and 2 days post-feeding were generated and sequenced. Fewer than 80 genes responded differentially to the presence of CHIKV in midguts of mosquitoes that had acquired the virus along with SM or PM. SM feeding induced differential expression (DE) of 479 genes at day 1 and 314 genes at day 2 when compared to midguts of sugarfed mosquitoes. By comparison, PM feeding induced 6029 DE genes at day 1 and 7368 genes at day 2. Twenty-three DE genes encoding trypsins, metalloproteinases, and serine-type endopeptidases were significantly upregulated in midguts of mosquitoes at day 1 following SM or PM ingestion. Two of these genes were
Ae. aegypti
late trypsin (
AeLT
) and serine collagenase 1 precursor (
AeSP1
). In vitro, recombinant AeLT showed strong matrix metalloproteinase activity whereas recombinant AeSP1 did not.
Conclusions
By substituting a bloodmeal for SM, we identified midgut-expressed genes not involved in blood or protein digestion. These included genes coding for trypsins, metalloproteinases, and serine-type endopeptidases, which could be involved in facilitating midgut escape for arboviruses in
Ae. aegypti
. The presence of CHIKV in any of the ingested meals had relatively minor effects on the overall gene expression profiles in midguts.
Journal Article
Infection Pattern of Mayaro Virus in Aedes aegypti (Diptera: Culicidae) and Transmission Potential of the Virus in Mixed Infections With Chikungunya Virus
Mayaro virus (MAYV; Togaviridae; Alphavirus) has drawn increasing attention as an arthropod-borne virus with potential to cause outbreaks among the human populations of the Western Hemisphere. In the tropical regions of Central and South America, the virus exists in sylvatic cycles between mosquitoes and primate reservoirs such as marmosets. Although forest-dwelling mosquitoes are regarded as important vectors for MAYV, it has been shown previously that the virus can infect and potentially be transmitted by the mosquitoes, Aedes aegypti and Aedes albopictus (Diptera: Culicidae). Here, we compare the infection and transmission efficiencies of two MAYV strains, IQT 4235 from Iquitos, Peru (‘IQT’) and the type strain of MAYV from Trinidad, TRVL 4675 (‘TRVL’) in two laboratory-adapted Ae. aegypti strains, Higgs White Eye and Orlando. The TRVL strain was less efficiently transmitted by both mosquito strains than MAYV IQT. Based on the full-length nucleotide sequences of the two viral genomes, we show that the TRVL prototype strain of MAYV is phylogenetically ancestral and more distantly related to the IQT strain. The TRVL strain efficiently infected wild-type Ae. albopictus from Missouri and readily disseminated in those. Considering scenarios in which natural MAYV transmission cycles may overlap with those of chikungunya virus (CHIKV; Togaviridae; Alphavirus), we assessed the effects of mixed infections of the two viruses in mosquitoes based on coinfection or superinfection. Although coinfection had no measurable effect on the transmission potential of either virus, we observed superinfection exclusion for CHIKV in MAYV-infected mosquitoes but not for MAYV in CHIKV-infected mosquitoes.
Journal Article