Isolation and Complete Genome Sequence Analysis of Kosakonia cowanii Pa82, a Novel Pathogen Causing Bacterial Wilt on Patchouli

Pogostemon cablin (patchouli), an important medicinal and aromatic plant, is widely used in traditional Chinese medicine as well as in perfume industry. Patchouli plants are susceptible to bacterial wilt disease, which causes significant economic losses by reduction in yield and quality of the plant products. However, few studies focus on the pathogens causing bacterial wilt on patchouli. In this study, strain Pa82 was isolated from diseased patchouli plants with typical bacterial wilt symptoms in Guangdong province, China, and was confirmed to be a highly virulent pathogen of patchouli bacterial wilt. Comparative sequence analysis of 16S rRNA gene showed that the strain was closely related to Kosakonia sp. CCTCC M2018092 (99.9% similarity) and Kosakonia cowanii Esp_Z (99.8% similarity). Moreover, phylogenetic tree based on 16S rRNA gene sequences showed that the strain was affiliated with genus Kosakonia. Further, the whole genome of strain Pa82 was sequenced, and the sequences were assembled and annotated. The complete genome of the strain consists of one chromosome and three plasmids. Average nucleotide identity (ANI) and phylogenetic analysis revealed that the strain belongs to Kosakonia cowanii (designated Kosakonia cowanii Pa82). Virulence-related genes of the strain involved in adherence, biofilm formation, endotoxin and other virulence factors were predicted. Among them, vgrG gene that encodes one of the type VI secretion system components was functionally validated as a virulence factor in Kosakonia cowanii Pa82 through construction of Tn5 insertion mutants and identification of mutant defective in virulence.

Isolation, Identification, and Whole-Genome Sequence Analysis of Pantoea Agglomerans Causing Leaf Spot-Hole Disease in Wild Apricot in Xinjiang, China

Wild apricot in Yili wild fruit forest in Xinjiang have been seriously affected by leaf spot-hole disease, with the incidence reaching 100%. To identify the pathogen of apricot perforation in the Yili wild fruit forest, two bacterial strains with strong virulence were obtained by the dilution separation method. The bacterial strains were gram-negative bacteria with yellow colonies, smooth surfaces and neat edges. The results of the pathogenicity test showed that the bacteria could cause symptoms of leaf spot-hole disease in wild apricot, similar to the symptoms in the field, and could cause HR in tobacco. Based on the 16S rDNA gene sequence and multilocus sequence analysis of fusA, gyrB, leuS, pyrG, rpoB and rlpB, combined with the physiological and biochemical characteristics, the isolated strain was identified as Pantoea agglomerans. The pathogen causing bacterial leaf spot-hole disease in wild apricot was determined to be P. agglomerans in the wild fruit forest of Yili, Xinjiang. The whole genome of the pathogen strain GL9-2 was sequenced based on the Illumina HiSeq500 and PacBio RS platforms. The genome size was 4765392 bp, and the G+C value was 55.27%. There was one chromosome and two plasmids in the genome, and 4353 CDs were identified. The annotation results showed that 52 glycoside hydrolase-related genes, 38 bacterial secretory system-related genes and 600 toxin-related genes were predicted.

Using Sequence Analysis to Identify Conversational Motifs in Supportive Interactions

This study demonstrates how sequence analysis, which is a method for identifying common patterns in categorical time series data, illuminates the nonlinear dynamics of dyadic conversations by describing chains of behavior that shift categorically, rather than incrementally. When applied to interpersonal interactions, sequence analysis supports the identification of conversational motifs, which can be used to test hypotheses linking patterns of interaction to conversational antecedents or outcomes. As an illustrative example, this study evaluated 285 conversations involving stranger, friend, and dating dyads in which one partner, the discloser, communicated about a source of stress to a partner in the role of listener. Using sequence analysis, we identified three five-turn supportive conversational motifs that had also emerged in a previous study of stranger dyads: discloser problem description, discloser problem processing, and listener-focused dialogue. We also observed a new, fourth motif: listener-focused, discloser questioning. Tests of hypotheses linking the prevalence and timing of particular motifs to the problem discloser’s emotional improvement and perceptions of support quality, as moderated by the discloser’s pre-interaction stress, offered a partial replication of previous findings. The discussion highlights the value of using sequence analysis to illuminate dynamic patterns in dyadic interactions.

Analysis of Simian Endogenous Retrovirus (SERV) Full-Length Proviruses in Old World Monkey Genomes

Simian endogenous retrovirus, SERV, is a successful germ line invader restricted to Old World monkey (OWM) species. (1) Background: The availability of high-quality primate genomes warrants a study of the characteristics, evolution, and distribution of SERV proviruses. (2) Methods: Cercopithecinae OWM genomes from public databases were queried for the presence of full-length SERV proviruses. A dataset of 81 Cer-SERV genomes was generated and analyzed. (3) Results: Full-length Cer-SERV proviruses were mainly found in terrestrial OWM, and less so in arboreal, forest- dwelling monkeys. Phylogenetic analysis confirmed the existence of two genotypes, Cer-SERV-1 and Cer-SERV-2, with Cer-SERV-1 showing evidence of recent germ-line expansions. Long Terminal Repeat (LTR) variation indicated that most proviruses were of a similar age and were estimated to be between <0.3 and 10 million years old. Integrations shared between species were relatively rare. Sequence analysis further showed extensive CpG methylation-associated mutations, variable Primer Binding Site (PBS) use with Cer-SERV-1 using PBSlys3 and Cer-SERV-2 using PBSlys1,2, and the recent gain of LTR motifs for transcription factors active during embryogenesis in Cer-SERV-1. (4) Conclusions: sequence analysis of 81 SERV proviruses from Cercopithecinae OWM genomes provides evidence for the adaptation of this retrovirus to germ line reproduction.

Identification of an Amylomaltase from the Halophilic Archaeon Haloquadratum walsbyi by Functional Metagenomics: Structural and Functional Insights

Amylomaltases are prokaryotic 4-α-glucanotransferases of the GH77 family. Thanks to the ability to modify starch, they constitute a group of enzymes of great interest for biotechnological applications. In this work we report the identification, by means of a functional metagenomics screening of the crystallization waters of the saltern of Margherita di Savoia (Italy), of an amylomaltase gene from the halophilic archaeon Haloquadratum walsbyi, and its expression in Escherichia coli cells. Sequence analysis indicated that the gene has specific insertions yet unknown in homologous genes in prokaryotes, and present only in amylomaltase genes identified in the genomes of other H. walsbyi strains. The gene is not part of any operon involved in the metabolism of maltooligosaccharides or glycogen, as it has been found in bacteria, making it impossible currently to assign a precise role to the encoded enzyme. Sequence analysis of the H. walsbyi amylomaltase and 3D modelling showed a common structure with homologous enzymes characterized in mesophilic and thermophilic bacteria. The recombinant H. walsbyi enzyme showed starch transglycosylation activity over a wide range of NaCl concentrations, with maltotriose as the best acceptor substrate compared to other maltooligosaccharides. This is the first study of an amylomaltase from a halophilic microorganism.

Trajectories of Spatial Assimilation or Place Stratification? A Typology of Residence and Workplace Histories of Newly Arrived Migrants in Sweden

In most societies, resources and opportunities are concentrated in neighborhoods and workplaces occupied by the host population. The spatial assimilation and place stratification theories propose trajectories (the sequences of events) leading to minority and migrant access to or exclusion from these advantageous places. However, most previous research on these theories did not ask whether such theorized trajectories occur. We apply sequence analysis to decade-long residence and workplace histories of newly arrived migrants in Sweden to identify a typology of combined residence-work trajectories. The seven types of trajectories in our typology are characterized by varying degrees of proximity to the host population in residential neighborhoods and workplaces and by different patterns of change in such proximity over time. The pivotal role of socioeconomic gains in spatial assimilation, posited by the namesake theory, is not supported, as we do not find that migrant employment precedes residence alongside the host population. The importance of housing-market discrimination for migrants’ exclusion from host-dominated spaces, posited by place stratification theory, is only weakly supported, as we find that migrants from less affluent countries accumulate disadvantage over time, likely due to discrimination in both the labor and housing markets. Our findings also underscore the need for new theories explaining migrant residential outcomes which apply to contexts where migrant-dense neighborhoods are still forming.

Cryo-EM structure of human somatostatin receptor 2 complex with its agonist somatostatin delineates the ligand binding specificity

Somatostatin is a peptide hormone regulating endocrine systems through binding to G-protein-coupled somatostatin receptors. somatostatin receptor 2 (SSTR2) is one of the human somatostatin receptors and highly implicated in cancers and neurological disorders. Here, we report the high resolution cryo-EM structure of full-length human SSTR2 bound to the agonist somatostatin (SST-14) complex with inhibitory G (Gi) proteins. Our structure shows that seven transmembrane helices form a deep pocket for ligand binding and that the highly conserved Trp-Lys motif of SST-14 positions at the bottom of the pocket. Furthermore, our sequence analysis combined with AlphaFold modeled structures of other SSTR isoforms provide how SSTR family proteins specifically interact with their cognate ligands. This work provides the first glimpse into the molecular recognition of somatostatin receptor and crucial resource to develop therapeutics targeting somatostatin receptors.

Investigation of a Limited but Explosive COVID-19 Outbreak in a German Secondary School

The role of schools as a source of infection and driver in the coronavirus-pandemic has been controversial and is still not completely clarified. To prevent harm and disadvantages for children and adolescents, but also adults, detailed data on school outbreaks is needed, especially when talking about open schools employing evidence-based safety concepts. Here, we investigated the first significant COVID-19 school outbreak in Hamburg, Germany, after the re-opening of schools in 2020. Using clinical, laboratory, and contact data and spatial measures for epidemiological and environmental studies combined with whole-genome sequencing (WGS) analysis, we examined the causes and the course of the secondary school outbreak. The potential index case was identified by epidemiological tracking and the lessons in classrooms with presumably high virus spreading rates and further infection chains in the setting. Sequence analysis of samples detected one sample of a different virus lineage and 25 virus genomes with almost identical sequences, of which 21 showed 100% similarity. Most infections occurred in connection with two lesson units of the primary case. Likely, 31 students (12–14 years old), two staff members, and three family members were infected in the school or the typical household. Sequence analysis revealed an outbreak cluster with a single source that was epidemiologically identified as a member of the educational staff. In lesson units, two superspreading events of varying degrees with airborne transmission took place. These were influenced by several parameters including the exposure times, the use of respiratory masks while speaking and spatial or structural conditions at that time.