Virus discovery in cultured portunid crabs: Genomic, phylogenetic, histopathological and microscopic characterization of a reovirus and a new bunyavirus.

Portunid crabs are distributed worldwide and highly valued in aquaculture. Viral infections are the main limiting factor for the survival of these animals and, consequently, for the success of commercial-scale cultivation. However, there is still a lack of knowledge about the viruses that infect cultured portunid crabs worldwide. Herein, the genome sequence and phylogeny of Callinectes sapidus reovirus 2 (CsRV2) are described, and the discovery of a new bunyavirus in Callinectes danae cultured in southern Brazil is reported. The CsRV2 genome sequence consists of 12 dsRNA segments (20,909 nt) encode 13 proteins. The predicted RNA-dependent RNA polymerase (RdRp) shows a high level of similarity with that of Eriocheir sinensis reovirus 905, suggesting that CsRV2 belongs to the genus Cardoreovirus. The CsRV2 particles are icosahedral, measuring approximately 65 nm in diameter, and exhibit typical non-turreted reovirus morphology. High throughput sequencing data revealed the presence of an additional putative virus genome similar to bunyavirus, called Callinectes danae Portunibunyavirus 1 (CdPBV1). The CdPBV1 genome is tripartite, consisting of 6,654 nt, 3,120 nt and 1,656 nt single-stranded RNA segments that each encode a single protein. Each segment has a high identity with European shore crab virus 1, suggesting that CdPBV1 is a new representative of the family Cruliviridae. The putative spherical particles of CdPBV1 measure ∼120 nm in diameter and present a typical bunyavirus morphology. The results of the histopathological analysis suggest that these new viruses can affect the health and, consequently, the survival of C. danae in captivity. Therefore, the findings reported here should be used to improve prophylactic and pathogen control practices and contribute to the development and optimization of the production of soft-shell crabs on a commercial scale in Brazil.

Associations Among Social Jet Lag, Sleep-Related Characteristics, and Burnout of Nurses in Tertiary Hospitals.

To investigate the status of social jet lag (SJL) through sociodemographic factors among clinical nurses and examine the correlation with burnout. There has been relatively little research on the possible factors resulting in SJL among nurses in China and its role in burnout. A multicenter cross-sectional study recruited 596 nurses from 7 Chinese hospitals. Online questionnaires were delivered to assess sociodemographics, shift work, SJL, chronotypes, and the burnout of nurses. Nurses had severe levels of SJL. The number of children, forms of employment, specialty area, length of professional service, and chronotypes were the main predictors of SJL. Moreover, SJL affected burnout (emotional exhaustion and deindividuation), and reducing the nurses' SJL could relieve their burnout. Additional evidence-based interventions indicate that reducing the SJL is essential as the nurses are suffering severe job burnout.

Safety and Efficacy of OGT-Assisted Overlap Oesophagojejunostomy Versus the Traditional Overlap Method in Laparoscopic Total Gastrectomy for Gastric/Gastroesophageal Junction (G/GEJ) Tumours.

INTRODUCTION: Overlap guiding tube (OGT)-assisted overlap oesophagojejunostomy (EJS), which was first designed and reported by our team, has shown feasibility. However, its safety and efficiency have not yet been compared with the conventional overlap approach. METHODS: We retrospectively analysed the data of 155 gastric/gastroesophageal junction (G/GEJ) cancer patients who underwent laparoscopic total gastrectomy by conventional (conventional group, n = 83) or OGT-assisted (OGT group, n = 72) overlap methods at Nanfang Hospital. The anastomotic efficiency and surgical outcomes were compared between the two groups. RESULTS: The success rate of inserting an anvil fork into the oesophageal lumen at the first attempt in the OGT group was much higher than in the conventional group (86.7% vs. 97.2%, P = 0.019). Consistently, the duration of EJS (P < 0.001) in the OGT group was significantly shorter than that in the conventional group. Operatively, there was one case in which oesophageal pseudocanals developed; another case was converted to thoracoscopic surgery in the conventional group, but there were no such cases in the OGT group. In terms of postoperative recovery, the OGT group was superior to the conventional group. The incidence of postoperative complications (28.9% vs. 20.8%, P = 0.247) and the classification of complication severity (P = 0.450) were milder in the OGT group, although the difference was not statistically significant. Notably, the conventional group had four cases (4.8%) of oesophagojejunal anastomotic leakage (EJAL) and one case (1.2%) of anastomotic stenosis. In the OGT group, two patients (2.8%) developed EJAL, but none developed anastomotic stenosis or anastomotic bleeding. Neither group had any cases of unplanned secondary surgery or perioperative deaths. CONCLUSIONS: The OGT-assisted method reduced the surgical difficulty of overlap EJS with good safety. This study provides new perspectives for optimizing EJS.

Impact of preoperative therapy on surgical outcomes of laparoscopic total gastrectomy for gastric/gastroesophageal junction cancer.

Objective: As laparoscopic surgery is widely applied for primarily treated gastric cancer (GC)/gastroesophageal junction cancer (GEJC) and gains many advantages, the feasibility of laparoscopic total gastrectomy (LTG) for GC/GEJC patients who have received preoperative therapy (PT) has come to the fore. This study aims to analyze the safety and feasibility of LTG after PT for GC/GEJC patients. Methods: We retrospectively analyzed the data of 511 patients with GC/GEJC undergoing LTG, of which 405 received LTG (LTG group) and 106 received PT+LTG (PT-LTG group) at Nanfang Hospital between June 2018 and September 2022. The surgical outcomes were compared between the two groups. Results: The surgical duration was significantly longer in the PT-LTG group (P<0.001), while the incidence of intraoperative complications (P=1.000), postoperative complications (LTG group vs. PT-LTG group: 26.2% vs. 23.6%, P=0.587), the classification of complication severity (P=0.271), and postoperative recovery was similar between two groups. Notably, the incidence of anastomotic complications of esophagojejunostomy was also comparable between the two groups (LTG group vs. PT-LTG group: 5.9% vs. 5.7%, P=0.918). The univariate and multivariate analysis confirmed that positive proximal margin [positive vs. negative: odds ratio (OR)=14.094, 95% confidence interval (95% CI): 2.639-75.260, P=0.002], rather than PT, has an impact on anastomotic complications after LTG (OR=0.945, 95% CI: 0.371-2.408, P=0.905). Conclusions: PT did not increase the surgical risk of LTG for GC/GEJC. Therefore, considering the positive effect of PT on long-term survival, the broader application of PT and LTG for GC/GEJC is supported by our findings.

High prevalence of CsRV2 in cultured Callinectes danae: Potential impacts on soft-shell crab production in Brazil.

Crabs can be infected by a variety of pathogenic micro-organisms but the most damaging are viruses. Naturally-occurring Callinectes sapidus reovirus 1 (CsRV1) is thought to contribute to mortality of Callinectes sapidus in soft crab culture in the USA. In Brazil, soft crabs are frequently produced using Callinectes danae, which suffers a similar rate of mortality in culture as C. sapidus. This study investigated whether CsRV1 could be detected in healthy or dead Callinectes danae from Paraná, Brazil and kept in captivity, we also evaluated the relationship between viral infection, and biochemical and behavioral parameters. C. danae from Paranaguá Bay were kept in a recirculation system for 14 days and subjected to weekly biochemical analyses and a reflex action mortality predictors (RAMP) test. RT-qPCR assays for CsRV1 were negative for all samples. However, electrophoretic analysis of extracted RNA from some crabs showed a pattern of 12 dsRNA bands that indicated intense infection by a reovirus with a genome organization different from CsRV1. The banding pattern was indistinguishable from a putative novel reovirus detected in C. sapidus in Rio Grande do Sul, Brazil, provisionally called CsRV2. The prevalence of dsRNA of CsRV2 showed no significant difference between crabs that died and survived. Interestingly, the presence of CsRV2 dsRNA was correlated with a significant reduction in glycogen concentration in hepatopancreas and a decrease in reflex action. The results obtained in this study are an early glimpse of the occurrence of reoviruses in C. danae and their potential effects in soft-shell crab systems in Brazil.

Survival analysis of elderly patients over 65 years old with stage II/III gastric cancer treated with adjuvant chemotherapy after laparoscopic D2 gastrectomy: a retrospective cohort study.

BACKGROUND: The benefits of adjuvant chemotherapy for elderly patients with gastric cancer (GC) remain unknown because elderly patients are underrepresented in most clinical trials. This study aimed to evaluate the effectiveness and complications of adjuvant chemotherapy in patients > 65 years of age after laparoscopic D2 gastrectomy. METHODS: This was a single-center retrospective cohort study of elderly patients (> 65 years) with stage II/III GC who underwent curative laparoscopic D2 gastrectomy with R0 resection between 2004 and 2018. The adjuvant chemotherapy regimens included monotherapy (oral capecitabine) and doublet chemotherapy (oral capecitabine plus intravenous oxaliplatin [XELOX] or intravenous oxaliplatin, leucovorin, and 5-fluorouracil [FOLFOX]). The data were retrieved from a prospectively registered database maintained at the Department of General Surgery in Nanfang Hospital, China. The patients were divided as surgery alone and surgery plus adjuvant chemotherapy (chemo group). The overall survival (OS), disease-free survival (DFS), chemotherapy duration, and toxicity were examined. RESULTS: There were 270 patients included: 169 and 101 in the surgery and chemo groups, respectively. There were 10 (10/101) and six (6/101) patients with grade 3+ non-hematological and hematological adverse events. The 1-/3-/5-year OS rates of the surgery group were 72.9%/51.8%/48.3%, compared with 90.1%/66.4%/48.6% for the chemo group (log-rank test: P = 0.018). For stage III patients, the 1-/3-/5-year OS rates of the surgery group were 83.7%/40.7%/28.7%, compared with 89.9%/61.2%/43.6% for the chemo group (log-rank test: P = 0.015). Adjuvant chemotherapy was significantly associated with higher OS (HR = 0.568, 95%CI: 0.357-0.903, P = 0.017) and DFS (HR = 0.511, 95%CI: 0.322-0.811, P = 0.004) in stage III patients. CONCLUSIONS: This study suggested that adjuvant chemotherapy significantly improves OS and DFS compared with surgery alone in elderly patients with stage III GC after D2 laparoscopic gastrectomy, with a tolerable adverse event profile.

Diversity and classification of reoviruses in crustaceans: A proposal.

A variety of reoviruses have been described in crustacean hosts, including shrimp, crayfish, prawn, and especially in crabs. However, only one genus of crustacean reovirus - Cardoreovirus - has been formally recognized by ICTV (International Committee on Taxonomy of Viruses) and most crustacean reoviruses remain unclassified. This arises in part from ambiguous or incomplete information on which to categorize them. In recent years, increased availability of crustacean reovirus genomic sequences is making the discovery and classification of crustacean reoviruses faster and more certain. This minireview describes the properties of the reoviruses infecting crustaceans and suggests an overall classification of brachyuran crustacean reoviruses based on a combination of morphology, host, genome organization pattern and phylogenetic sequence analysis.

Enhanced recovery after surgery in laparoscopic distal gastrectomy: Protocol for a prospective single-arm clinical trial.

BACKGROUND: The enhanced recovery after surgery (ERAS) programme is feasible and effective in reducing the length of hospital stay, overall complication rates and medical costs when applied to cases involving colonic and rectal resections. However, a recent prospective, randomised, open, parallel-controlled trial (Chinese Laparoscopic Gastrointestinal Surgery Study-01 trial), initiated by our team, indicated that under conventional peri-operative management, the reduction of the post-operative hospital stay of laparoscopic distal gastrectomy (LDG) is quite limited compared with open gastrectomy. Thus, if we could provide valuable clinical evidence for demonstrating the efficacy of the ERAS programme for gastric cancer patients undergoing LDG, it would significantly enhance the peri-operative management of gastrectomy and benefit the patients. METHODS: In this prospective single-arm trial, patients who are 18-75 years of age with gastric adenocarcinoma diagnosed with cT1-4aN0-3M0 and expected to undergo curative resection through LDG, are considered eligible for this study. All participants underwent LDG with peri-operative management under the ERAS programme. The primary outcome measures included the post-operative hospital stays and rehabilitative rate of the post-operative day 4. The secondary outcome measures are morbidity and mortality (time frame: 30 days), post-operative recovery index (time frame: 30 days), post-operative pain intensity (time frame: 3 days) and the medical costs from surgery to discharge. CONCLUSION: With reasonable and scientific designing, the trial may be a great help to further discuss the benefit of ERAS programme and thus improving the peri-operative management of patients with gastrectomy.

Physiological characteristics and metabolomics reveal the tolerance mechanism to low nitrogen in Glycine soja leaves.

To explore the regulatory mechanisms involved in the adaption to nitrogen (N) deficiency of wild soybean, the ion balance, photosynthetic characteristics, metabolic and transcriptional changes in leaves of common and low N (LN)-tolerant wild soybean seedlings under LN stress were determined. The LN-tolerant wild soybean seedlings showed a stronger ability to maintain photosynthesis and nutrient balance than common wild soybean. A total of 52 differentially accumulated metabolites, mainly related to carbon and N metabolism, were identified between the control and the LN treatment group. In general, tricarboxylic acid (TCA) cycle, shikimic acid pathway, synthetase/glutamate synthase (GS/GOGAT) cycle and accumulation of most organic acids were enhanced in LN-tolerant wild soybean, while reduced in common wild soybean under LN stress compared with their respective control group. Moreover, glycolysis, sugar and polyol and fatty acid metabolism increased in both wild soybean genotypes, and increased more in LN-tolerant wild soybean. A total of 3381 differentially expressed genes (DEGs) were identified in leaves of both wild soybean genotypes and the expressed level of DEGs associated with sugars, polyols, fatty acids and energy metabolism was significantly higher in LN-tolerant wild soybean than in common wild soybean, consistent with changes in metabolite level. Our results suggest new ideas for the study of LN tolerance of wild soybean and provide a theoretical basis for development and utilization of wild soybean resources.

Histones and chymotrypsin-like elastases play significant roles in the antimicrobial activity of tongue sole neutrophil extracellular traps.

Neutrophil extracellular traps (NETs) are a form of extracellular antimicrobial structure of neutrophils observed in higher and lower vertebrates, the latter including the teleost fish tongue sole Cynoglossus semilaevis. However, the antimicrobial mechanism of fish NETs is unknown. In the present study, we examined the potential contribution of histones and elastases to the antibacterial effect of tongue sole NETs. For this purpose, two histones (CsH2B and CsH4) and two elastases (CsEla1 and CsEla2) of tongue sole were investigated. The histones and elastases possess the conserved domain structures characteristic of that of histones H2B/H4 and trypsin-like serine protease, respectively. Recombinant CsH2B, CsH4, CsEla1, and CsEla2 bound a wide range of Gram-negative and Gram-positive bacteria, and some of the bound bacteria were inhibited in growth by the bound histones/elastases. CsH2B, CsH4, CsEla1, and CsEla2 were all localized in NETs induced by various stimuli including bacterial pathogen. Treatment of NETs with antibodies targeting CsH2B, CsH4, CsEla1, and CsEla2 significantly reduced the antimicrobial effect of NETs. These results indicate that histones and chymotrypsin-like elastases are fundamental components of teleost NETs that play important roles in the antimicrobial activity of NETs.

Exploring the Value of MRI Measurement of Hippocampal Volume for Predicting the Occurrence and Progression of Alzheimer's Disease Based on Artificial Intelligence Deep Learning Technology and Evidence-Based Medicine Meta-Analysis.

BACKGROUND: Alzheimer's disease (AD), a major dementia cause, lacks effective treatment. MRI-based hippocampal volume measurement using artificial intelligence offers new insights into early diagnosis and intervention in AD progression. OBJECTIVE: This study, involving 483 AD patients, 756 patients with mild cognitive impairment (MCI), and 968 normal controls (NC), investigated the predictive capability of MRI-based hippocampus volume measurements for AD risk using artificial intelligence and evidence-based medicine. METHODS: Utilizing data from ADNI and OASIS-brains databases, three convolutional neural networks (InceptionResNetv2, Densenet169, and SEResNet50) were employed for automated AD classification based on structural MRI imaging. A multitask deep learning model and a densely connected 3D convolutional network were utilized. Additionally, a systematic meta-analysis explored the value of MRI-based hippocampal volume measurement in predicting AD occurrence and progression, drawing on 23 eligible articles from PubMed and Embase databases. RESULTS: InceptionResNetv2 outperformed other networks, achieving 99.75% accuracy and 100% AUC for AD-NC classification and 99.16% accuracy and 100% AUC for MCI-NC classification. Notably, at a 512×512 size, InceptionResNetv2 demonstrated a classification accuracy of 94.29% and an AUC of 98% for AD-NC and 97.31% accuracy and 98% AUC for MCI-NC. CONCLUSIONS: The study concludes that MRI-based hippocampal volume changes effectively predict AD onset and progression, facilitating early intervention and prevention.

Engineering Escherichia coli for Highly Efficient Biosynthesis of Lacto-N-difucohexaose II through De Novo GDP-l-fucose Pathway.

Lacto-N-difucohexaose II (LNDFH II) is a typical fucosylated human milk oligosaccharide and can be enzymatically produced from lacto-N-tetraose (LNT) by a specific α1,3/4-fucosyltransferase from Helicobacter pylori DMS 6709, referred to as FucT14. Previously, we constructed an engineered Escherichia coli BL21(DE3) with a single plasmid for highly efficient biosynthesis of LNT. In this study, two additional plasmids harboring the de novo GDP-L-fucose pathway module and FucT14, respectively, were further introduced to construct the strain for successful biosynthesis of LNDFH II. FucT14 was actively expressed, and the engineered strain produced LNDFH II as the major product, lacto-N-fucopentaose (LNFP) V as the minor product, and a trace amount of LNFP II and 3-fucosyllactose as very minor products. Additional expression of the α1,3-fucosyltransferase FutM1 from a Bacteroidaceae bacterium from the gut metagenome could obviously enhance the LNDFH II biosynthesis. After optimization of induction conditions, the maximum titer reached 3.011 g/L by shake-flask cultivation. During the fed-batch cultivation, LNDFH II was highly efficiently produced with the highest titer of 18.062 g/L and the productivity yield of 0.301 g/L·h.

Microbial Synthesis of Lacto-N-fucopentaose I with High Titer and Purity by Screening of Specific Glycosyltransferase and Elimination of Residual Lacto-N-triose II and Lacto-N-tetraose.

Lacto-N-fucopentaose I (LNFP I) has recently been approved as generally recognized as safe, demonstrating its great commercial potential in the food industry. Microbial synthesis through metabolic engineering strategies is an effective approach for large-scale production of LNFP I. Biosynthesis of LNFP I requires consideration of two key points: high titer with low byproduct 2'-fucosyllactose (2'-FL) generation and high purity with low lacto-N-triose II (LNTri II) and lacto-N-tetraose (LNT) residues. Herein, α1,2-fucosyltransferase from Thermoanaerobacterium sp. RBIITD was screened from 16 selected LNFP I-producing glycosyltransferase candidates, showing the highest in vivo LNFP I productivity. Chromosomal integration of wbgO enhanced the LNFP I production by improving the precursor conversion from LNTri II to LNT. The best engineered strain produced 4.42 and 35.1 g/L LNFP I in shake-flask and fed-batch cultivation, respectively. The residual LNTri II and LNT were eliminated by further cultivation with a recombinant strain coexpressing Bifidobacterium bifidum ß-N-acetylhexosaminidase and lacto-N-biosidase. A strategy for LNFP I biosynthesis with high yield and purity was finally realized, providing support for its practical application in large-scale production.

Implementation of a Quorum-Sensing System for Highly Efficient Biosynthesis of Lacto-N-neotetraose in Engineered Escherichia coli MG1655.

Lacto-N-neotetraose (LNnT), a prominent neutral human milk oligosaccharide (HMO), serves as a pivotal structural element in complex HMO biosynthesis. Given its promising health effects for infants, the biosynthesis of LNnT is garnering greater interest. Using a previously engineered strain as a chassis, a highly effective LNnT producer was constructed. First, LNnT synthesis in Escherichia coli MG1655 was achieved by introducing ß1,3-N-acetylglucosaminyltransferase LgtA and ß1,4-galactosyltransferase CpsIaJ, coupled with the optimization of enzyme expression levels using various promoters. Subsequently, ugd underwent disruption, and the galE gene was enhanced by replacing its promoter with PJ23119 or Ptac. Then, a lux-type quorum sensing (QS) system was applied to achieve varied metabolic regulation. Additionally, systematic optimization of the QS promoters was conducted to further improve the LNnT titer in the shake flask. Finally, the extracellular titer of LNnT was 20.33 g/L, accompanied by a productivity of 0.41 g/L/h.

Recent advances on N-acetylneuraminic acid: Physiological roles, applications, and biosynthesis.

N-Acetylneuraminic acid (Neu5Ac), the most common type of Sia, generally acts as the terminal sugar in cell surface glycans, glycoconjugates, oligosaccharides, lipo-oligosaccharides, and polysaccharides, thus exerting numerous physiological functions. The extensive applications of Neu5Ac in the food, cosmetic, and pharmaceutical industries make large-scale production of this chemical desirable. Biosynthesis which is associated with important application potential and environmental friendliness has become an indispensable approach for large-scale synthesis of Neu5Ac. In this review, the physiological roles of Neu5Ac was first summarized in detail. Second, the safety evaluation, regulatory status, and applications of Neu5Ac were discussed. Third, enzyme-catalyzed preparation, whole-cell biocatalysis, and microbial de novo synthesis of Neu5Ac were comprehensively reviewed. In addition, we discussed the main challenges of Neu5Ac de novo biosynthesis, such as screening and engineering of key enzymes, identifying exporters of intermediates and Neu5Ac, and balancing cell growth and biosynthesis. The corresponding strategies and systematic strategies were proposed to overcome these challenges and facilitate Neu5Ac industrial-scale production.

Efficient Production of N-Acetylneuraminic Acid in Escherichia coli Based on the UDP-N-Acetylglucosamine Biosynthetic Pathway.

N-Acetylneuraminic acid (NeuAc) is the predominant sialic acid found in human cells and a human-identical milk monosaccharide. Due to its numerous health benefits, it has great commercial potential in the pharmaceutical, cosmetic, and food industries. Microbial synthesis via metabolic engineering strategies is an important approach to its large-scale production. In this study, a NeuAc synthetic pathway was constructed in Escherichia coli BL21(DE3) by deleting the competitive pathway genes and introducing two genes encoding UDP-N-acetylglucosamine (GlcNAc) 2-epimerase (NeuC) and NeuAc synthase (NeuB). UDP-GlcNAc pathway genes, glmS, glmM, and glmU, were overexpressed to strengthen precursor supply for enhancement of NeuAc synthesis. The microbial source of neuC and neuB was optimized, and their expression was fine-tuned. In addition, glycerol as the carbon source showed a much better effect on NeuAc synthesis than glucose. The final engineered strain produced 7.02 g/L NeuAc by shake-flask cultivation. The titer was enhanced to 46.92 g/L by fed-batch cultivation, with the productivity of 0.82 g/L/h and 1.05 g/g DCW.

An Overview of Sugar Nucleotide-Dependent Glycosyltransferases for Human Milk Oligosaccharide Synthesis.

Human milk oligosaccharides (HMOs) have received increasing attention because of their special effects on infant health and commercial value as the new generation of core components in infant formula. Currently, large-scale production of HMOs is generally based on microbial synthesis using metabolically engineered cell factories. Introduction of the specific glycosyltransferases is essential for the construction of HMO-producing engineered strains in which the HMO-producing glycosyltransferases are generally sugar nucleotide-dependent. Four types of glycosyltransferases have been used for typical glycosylation reactions to synthesize HMOs. Soluble expression, substrate specificity, and regioselectivity are common concerns of these glycosyltransferases in practical applications. Screening of specific glycosyltransferases is an important research topic to solve these problems. Molecular modification has also been performed to enhance the catalytic activity of various HMO-producing glycosyltransferases and to improve the substrate specificity and regioselectivity. In this article, various sugar nucleotide-dependent glycosyltransferases for HMO synthesis were overviewed, common concerns of these glycosyltransferases were described, and the future perspectives of glycosyltransferase-related studies were provided.

Elimination of Residual Lacto-N-triose II for Lacto-N-tetraose Biosynthesis in Engineered Escherichia coli.

Lacto-N-tetraose (LNT) is an important neutral human milk oligosaccharide (HMO) and acts as a significant core structure for complex HMO biosynthesis. We previously achieved high-yield LNT biosynthesis (57.5 g/L) using fed-batch fermentation; however, residual lacto-N-triose II (LNTri II) was also found (21.58 g/L). Here, we re-engineered an efficient LNT-producing Escherichia coli with low LNTri II accumulation using genetically stable LNTri II-producing strains with a genomic insertion of lgtA (encoding ß1,3-N-acetylglucosaminyltransferase). Comparable and low titers of LNT (3.73-4.61 g/L) and LNTri II (0.33-0.63 g/L), respectively, were obtained by introducing ß1,3-galactosyltransferase. To reduce residual LNTri II, the E. coli transporter gene setA was disrupted, obviously reducing the accumulation of LNTri II and LNT. Next, the gene encoding ß-N-acetylhexosaminidase (BbhI) was introduced into LNT-producing strains or E. coli BL21(DE3) for single- or mixed-strain cultivation, respectively. Finally, LNT was obtained (30.13 g/L) in a cocultivation system of mixed engineered strains without undesired LNTri II.

Cross-Hemispheric Genetic Diversity and Spatial Genetic Structure of Callinectes sapidus Reovirus 1 (CsRV1).

The movement of viruses in aquatic systems is rarely studied over large geographic scales. Oceanic currents, host migration, latitude-based variation in climate, and resulting changes in host life history are all potential drivers of virus connectivity, adaptation, and genetic structure. To expand our understanding of the genetic diversity of Callinectes sapidus reovirus 1 (CsRV1) across a broad spatial and host life history range of its blue crab host (Callinectes sapidus), we obtained 22 complete and 96 partial genomic sequences for CsRV1 strains from the US Atlantic coast, Gulf of Mexico, Caribbean Sea, and the Atlantic coast of South America. Phylogenetic analyses of CsRV1 genomes revealed that virus genotypes were divided into four major genogroups consistent with their host geographic origins. However, some CsRV1 sequences from the US mid-Atlantic shared high genetic similarity with the Gulf of Mexico genotypes, suggesting potential human-mediated movement of CsRV1 between the US mid-Atlantic and Gulf coasts. This study advances our understanding of how climate, coastal geography, host life history, and human activity drive patterns of genetic structure and diversity of viruses in marine animals and contributes to the capacity to infer broadscale host population connectivity in marine ecosystems from virus population genetic data.