4,493 research outputs found
Urban Areas as Potential Sinks for Tropical Swallowtail Moth Lyssa zampa
(1) The tropical swallowtail moth Lyssa zampa received much public attention during its years of mass emergence in Singapore and Southeast Asia. However, despite its prominence, little is known about its population demographics and spatial ecology. This study aims to establish the annual abundance of L. zampa, determine its spatial patterns of occurrence, and examine morphological variation demonstrated by L. zampa with an emphasis on comparing urban vs. forest areas in Singapore. (2) Various sources (field surveys across 18 sites, citizen science datasets and expert knowledge) were used to catalogue L. zampa records from 2011 to 2020 and analyse its seasonal abundance. (3) We confirmed the seasonal peak of L. zampa emergence to be between May and July, with an unusually high mass emergence in 2014. The intensity of emergence was associated with the intensity of a dry spell in February of that year. The total number of L. zampa sighted in urban areas was higher despite the moth’s host plant being a tree that is restricted to mature forests and is absent from urban areas. This suggests that the occurrence of L. zampa in urban areas is likely due to the moth’s attraction to bright city lights. Our morphometric measurements further show that L. zampa individuals in urban areas have greater wing length and lighter body weights (smaller body widths) than their forest counterparts. (4) This implies that urban areas are not only drawing moths that are unable to find the host plants and, therefore, cannot produce offspring but are also attracting larger and better flyers out of forest areas. This situation is only likely to worsen as climate change intensifies and dry spells become longer and more intense
Process parameters influencing tannase production by Aspergillus niger using mangrove (Rhizophora apiculata) bark in solid substrate fermentation
Rhizophora apiculata bark is a tannin-rich waste material obtained from charcoal industry. This industrial waste was used as solid substrate in the study for the production of tannase and at the same time, help in minimizing the country’s industrial wastes. This study was carried out to optimize the physical parameters for the maximal tannase production by Aspergillus niger via solid substrate fermentation using a shake flask system. The optimized physical parameters obtained were combination of 0.75 and 2.00 mm of substrate particles at the ratio of 1: 1, Czapek- Dox medium as moisturizing agent at pH 7, initial moisture content of 1: 1.5 (w/v), incubation temperature at 30°C, mixing at every 24 h and the size of inoculum at 1 × 106 spores/ml which finally, produced a maximum tannase of 4.97 U/g of fermented substrate on the 6th day of cultivation.Key words: Solid substrate fermentation, tannase, Aspergillus niger, Rhizophora apiculata barks
Erythropoietin-induced serine 727 phosphorylation of STAT3 in erythroid cells is mediated by a MEK-, ERK-, and MSK1-dependent pathway
Objective. Erythropoietin (EPO) is a key regulator of erythropoiesis, playing a role in both the proliferation and differentiation of erythroid cells. One of the signal transduction molecules activated upon EPO stimulation is signal transducer and activator of transcription (STAT) 3. Besides tyrosine 705 phosphorylation of STAT3, serine 727 phosphorylation has been described upon EPO stimulation. In the present study, we investigated which molecular pathways mediate the STAT3 serine 727 phosphorylation and the functional implications of this phosphorylation.
Methods. The EPO-dependent erythroid cell line ASE2 was used to investigate which signaling routes were involved in the STAT3 serine 727 phosphorylation. Western blotting using phosphospecific antibodies was used to assess the phosphorylation status of STAT3 molecules. Transfection analysis was performed to investigate the transactivational potential of STAT3, and quantitative RT-PCR was used to study the in vivo gene expression of STAT3-responsive genes.
Results. Western blotting of extracts of cells exposed to various chemical inhibitors revealed that the MEK inhibitors PD98059 and U0126 abrogated the EPO-mediated STAT3 serine 727 phosphorylation without an effect on tyrosine phosphorylation. Further analysis showed that MSK1 is activated downstream of ERK, and retroviral transductions with kinase-inactive MSK1 revealed that MSK1 is necessary for STAT3 serine phosphorylation. Furthermore, the STAT3-mediated transactivation was reduced by blocking the STAT3 serine phosphorylation with the MEK inhibitor U0126 or by expression of kinase-inactive MSK1.
Conclusions. The EPO-induced STAT3 serine 727 phosphorylation is mediated by a pathway involving MEK, ERK, and MSK1. Furthermore, serine phosphorylation of STAT3 augments the transactivational potential of STAT3.
Pathogenic Variants in Fucokinase Cause a Congenital Disorder of Glycosylation
FUK encodes fucokinase, the only enzyme capable of converting L-fucose to fucose-1-phosphate, which will ultimately be used for synthesizing GDP-fucose, the donor substrate for all fucosyltransferases. Although it is essential for fucose salvage, this pathway is thought to make only a minor contribution to the total amount of GDP-fucose. A second pathway, the major de novo pathway, involves conversion of GDP-mannose to GDP-fucose. Here we describe two unrelated individuals who have pathogenic variants in FUK and who presented with severe developmental delays, encephalopathy, intractable seizures, and hypotonia. The first individual was compound heterozygous for c.667T>C (p.Ser223Pro) and c.2047C>T (p.Arg683Cys), and the second individual was homozygous for c.2980A>C (p.Lys994Gln). Skin fibroblasts from the first individual confirmed the variants as loss of function and showed significant decreases in total GDP-[3H] fucose and [3H] fucose-1-phosphate. There was also a decrease in the incorporation of [5,6-3H]-fucose into fucosylated glycoproteins. Lys994 has previously been shown to be an important site for ubiquitin conjugation. Here, we show that loss-of-function variants in FUK cause a congenital glycosylation disorder characterized by a defective fucose-salvage pathway
Finding groups in data: Cluster analysis with ants
Wepresent in this paper a modification of Lumer and Faieta’s algorithm for data clustering. This approach
mimics the clustering behavior observed in real ant colonies. This algorithm discovers automatically
clusters in numerical data without prior knowledge of possible number of clusters. In this paper we focus
on ant-based clustering algorithms, a particular kind of a swarm intelligent system, and on the effects on
the final clustering by using during the classification differentmetrics of dissimilarity: Euclidean, Cosine,
and Gower measures. Clustering with swarm-based algorithms is emerging as an alternative to more
conventional clustering methods, such as e.g. k-means, etc. Among the many bio-inspired techniques, ant
clustering algorithms have received special attention, especially because they still require much
investigation to improve performance, stability and other key features that would make such algorithms
mature tools for data mining.
As a case study, this paper focus on the behavior of clustering procedures in those new approaches.
The proposed algorithm and its modifications are evaluated in a number of well-known benchmark
datasets. Empirical results clearly show that ant-based clustering algorithms performs well when
compared to another techniques
Antibodies to Enteroviruses in Cerebrospinal Fluid of Patients with Acute Flaccid Myelitis.
Acute flaccid myelitis (AFM) has caused motor paralysis in >560 children in the United States since 2014. The temporal association of enterovirus (EV) outbreaks with increases in AFM cases and reports of fever, respiratory, or gastrointestinal illness prior to AFM in >90% of cases suggest a role for infectious agents. Cerebrospinal fluid (CSF) from 14 AFM and 5 non-AFM patients with central nervous system (CNS) diseases in 2018 were investigated by viral-capture high-throughput sequencing (VirCapSeq-VERT system). These CSF and serum samples, as well as multiple controls, were tested for antibodies to human EVs using peptide microarrays. EV RNA was confirmed in CSF from only 1 adult AFM case and 1 non-AFM case. In contrast, antibodies to EV peptides were present in CSF of 11 of 14 AFM patients (79%), significantly higher than controls, including non-AFM patients (1/5 [20%]), children with Kawasaki disease (0/10), and adults with non-AFM CNS diseases (2/11 [18%]) (P = 0.023, 0.0001, and 0.0028, respectively). Six of 14 CSF samples (43%) and 8 of 11 sera (73%) from AFM patients were immunoreactive to an EV-D68-specific peptide, whereas the three control groups were not immunoreactive in either CSF (0/5, 0/10, and 0/11; P = 0.008, 0.0003, and 0.035, respectively) or sera (0/2, 0/8, and 0/5; P = 0.139, 0.002, and 0.009, respectively).IMPORTANCE The presence in cerebrospinal fluid of antibodies to EV peptides at higher levels than non-AFM controls supports the plausibility of a link between EV infection and AFM that warrants further investigation and has the potential to lead to strategies for diagnosis and prevention of disease
Dealing with non-metric dissimilarities in fuzzy central clustering algorithms
Clustering is the problem of grouping objects on the basis of a similarity measure among them. Relational clustering methods can be employed when a feature-based representation of the objects is not available, and their description is given in terms of pairwise (dis)similarities. This paper focuses on the relational duals of fuzzy central clustering algorithms, and their application in situations when patterns are represented by means of non-metric pairwise dissimilarities. Symmetrization and shift operations have been proposed to transform the dissimilarities among patterns from non-metric to metric. In this paper, we analyze how four popular fuzzy central clustering algorithms are affected by such transformations. The main contributions include the lack of invariance to shift operations, as well as the invariance to symmetrization. Moreover, we highlight the connections between relational duals of central clustering algorithms and central clustering algorithms in kernel-induced spaces. One among the presented algorithms has never been proposed for non-metric relational clustering, and turns out to be very robust to shift operations. (C) 2008 Elsevier Inc. All rights reserved
- …