Cryo-electron tomography reveals the packaging pattern of RuBisCOs in Synechococcus ß-carboxysome.

Carboxysomes are large self-assembled microcompartments that serve as the central machinery of a CO2-concentrating mechanism (CCM). Biogenesis of carboxysome requires the fine organization of thousands of individual proteins; however, the packaging pattern of internal RuBisCOs remains largely unknown. Here we purified the intact ß-carboxysomes from Synechococcus elongatus PCC 7942 and identified the protein components by mass spectrometry. Cryo-electron tomography combined with subtomogram averaging revealed the general organization pattern of internal RuBisCOs, in which the adjacent RuBisCOs are mainly arranged in three distinct manners: head-to-head, head-to-side, and side-by-side. The RuBisCOs in the outermost layer are regularly aligned along the shell, the majority of which directly interact with the shell. Moreover, statistical analysis enabled us to propose an ideal packaging model of RuBisCOs in the ß-carboxysome. These results provide new insights into the biogenesis of ß-carboxysomes and also advance our understanding of the efficient carbon fixation functionality of carboxysomes.

Profiling the interplay and coevolution of Microcystis aeruginosa and cyanosiphophage Mic1.

The cyanosiphophage Mic1 specifically infects the bloom-forming Microcystis aeruginosa FACHB 1339 from Lake Chaohu, China. Previous genomic analysis showed that its 92,627 bp double-stranded DNA genome consists of 98 putative open reading frames, 63% of which are of unknown function. Here, we investigated the transcriptome dynamics of Mic1 and its host using RNA sequencing. In the early, middle, and late phases of the 10 h lytic cycle, the Mic1 genes are sequentially expressed and could be further temporally grouped into two distinct clusters in each phase. Notably, six early genes, including gp49 that encodes a TnpB-like transposase, immediately reach the highest transcriptional level in half an hour, representing a pioneer cluster that rapidly regulates and redirects host metabolism toward the phage. An in-depth analysis of the host transcriptomic profile in response to Mic1 infection revealed significant upregulation of a polyketide synthase pathway and a type III-B CRISPR system, accompanied by moderate downregulation of the photosynthesis and key metabolism pathways. The constant increase of phage transcripts and relatively low replacement rate over the host transcripts indicated that Mic1 utilizes a unique strategy to gradually take over a small portion of host metabolism pathways after infection. In addition, genomic analysis of a less-infective Mic1 and a Mic1-resistant host strain further confirmed their dynamic interplay and coevolution via the frequent horizontal gene transfer. These findings provide insights into the mutual benefit and symbiosis of the highly polymorphic cyanobacteria M. aeruginosa and cyanophages. IMPORTANCE: The highly polymorphic Microcystis aeruginosa is one of the predominant bloom-forming cyanobacteria in eutrophic freshwater bodies and is infected by diverse and abundant cyanophages. The presence of a large number of defense systems in M. aeruginosa genome suggests a dynamic interplay and coevolution with the cyanophages. In this study, we investigated the temporal gene expression pattern of Mic1 after infection and the corresponding transcriptional responses of its host. Moreover, the identification of a less-infective Mic1 and a Mic1-resistant host strain provided the evolved genes in the phage-host coevolution during the multiple-generation cultivation in the laboratory. Our findings enrich the knowledge on the interplay and coevolution of M. aeruginosa and its cyanophages and lay the foundation for the future application of cyanophage as a potential eco-friendly and bio-safe agent in controlling the succession of harmful cyanobacterial blooms.

Structure and assembly of the α-carboxysome in the marine cyanobacterium Prochlorococcus.

Carboxysomes are bacterial microcompartments that encapsulate the enzymes RuBisCO and carbonic anhydrase in a proteinaceous shell to enhance the efficiency of photosynthetic carbon fixation. The self-assembly principles of the intact carboxysome remain elusive. Here we purified α-carboxysomes from Prochlorococcus and examined their intact structures using single-particle cryo-electron microscopy to solve the basic principles of their shell construction and internal RuBisCO organization. The 4.2 Å icosahedral-like shell structure reveals 24 CsoS1 hexamers on each facet and one CsoS4A pentamer at each vertex. RuBisCOs are organized into three concentric layers within the shell, consisting of 72, 32 and up to 4 RuBisCOs at the outer, middle and inner layers, respectively. We uniquely show how full-length and shorter forms of the scaffolding protein CsoS2 bind to the inner surface of the shell via repetitive motifs in the middle and C-terminal regions. Combined with previous reports, we propose a concomitant 'outside-in' assembly principle of α-carboxysomes: the inner surface of the self-assembled shell is reinforced by the middle and C-terminal motifs of the scaffolding protein, while the free N-terminal motifs cluster to recruit RuBisCO in concentric, three-layered spherical arrangements. These new insights into the coordinated assembly of α-carboxysomes may guide the rational design and repurposing of carboxysome structures for improving plant photosynthetic efficiency.

Structure of the intact tail machine of Anabaena myophage A-1(L).

The Myoviridae cyanophage A-1(L) specifically infects the model cyanobacteria Anabaena sp. PCC 7120. Following our recent report on the capsid structure of A-1(L), here we present the high-resolution cryo-EM structure of its intact tail machine including the neck, tail and attached fibers. Besides the dodecameric portal, the neck contains a canonical hexamer connected to a unique pentadecamer that anchors five extended bead-chain-like neck fibers. The 1045-Å-long contractile tail is composed of a helical bundle of tape measure proteins surrounded by a layer of tube proteins and a layer of sheath proteins, ended with a five-component baseplate. The six long and six short tail fibers are folded back pairwise, each with one end anchoring to the baseplate and the distal end pointing to the capsid. Structural analysis combined with biochemical assays further enable us to identify the dual hydrolytic activities of the baseplate hub, in addition to two host receptor binding domains in the tail fibers. Moreover, the structure of the intact A-1(L) also helps us to reannotate its genome. These findings will facilitate the application of A-1(L) as a chassis cyanophage in synthetic biology.

Porphyrin-Regulated Heterostructured Hydrogel Ionic Diode with a High Rectification Ratio and Output Voltage.

Nanochannel ionic diodes require extremely complex and expensive fabrication processes. Polyelectrolyte ionic diodes attracted widespread attention among ionic rectification systems due to their simplicity of development and the ability to break the size limits of the nanochannel. However, enhancement of their rectification ratio is still in the exploratory stage. In this study, chitosan (CS) hydrogels and sodium polyacrylate (PAAs) hydrogels were prepared as the substrates for the heterostructured ionic diodes. 5,10,15,20-Tetrakis(4-aminophenyl)-21H,23H-porphyrin (TAPP) was selected to regulate the rectification ratio of ionic diodes. By adding 0.05 wt % TAPP to the CS hydrogel, the rectification ratio of the ionic diode can be increased to 10, which is 4 times larger than that of the undoped ionic diode. In contrast, the rectification ratio of the ionic diodes with TAPP added in the PAAs hydrogel decreases to 2. In addition, the ionic diode composed of the TAPP-doped CS hydrogel and PAAs hydrogel has the characteristics of a high open-circuit voltage. The open-circuit voltage of the 10 mm × 10 mm × 4 mm heterojunction hydrogel reached 370 mV. The ionic diodes can be used as a self-powered power supply device.

COSMOS: a platform for real-time morphology-based, label-free cell sorting using deep learning.

Cells are the singular building blocks of life, and a comprehensive understanding of morphology, among other properties, is crucial to the assessment of underlying heterogeneity. We developed Computational Sorting and Mapping of Single Cells (COSMOS), a platform based on Artificial Intelligence (AI) and microfluidics to characterize and sort single cells based on real-time deep learning interpretation of high-resolution brightfield images. Supervised deep learning models were applied to characterize and sort cell lines and dissociated primary tissue based on high-dimensional embedding vectors of morphology without the need for biomarker labels and stains/dyes. We demonstrate COSMOS capabilities with multiple human cell lines and tissue samples. These early results suggest that our neural networks embedding space can capture and recapitulate deep visual characteristics and can be used to efficiently purify unlabeled viable cells with desired morphological traits. Our approach resolves a technical gap in the ability to perform real-time deep learning assessment and sorting of cells based on high-resolution brightfield images.

High-dose Tiger-Gian formula protects the knee joint from surgically induced osteoarthritis in rats.

AIM: Although the Tiger-Gian formula (TGF) has proven clinically effective at improving the symptoms of knee osteoarthritis (KOA), the pharmacological effects and underlying mechanisms of TGF have not been examined in any animal model. This study assessed the effects of TGF in male Sprague-Dawley rats with anterior cruciate ligament transection (ACLT) -induced KOA. METHODS: Thirty rats underwent ACLT surgery and were assigned to either the control group, ACLT alone, ACLT + low-dose TGF (1000 mg/kg), ACLT + high-dose TGF (3000 mg/kg), or ACLT + celecoxib (30 mg/kg). All rats were subjected to micro-computed tomography (micro-CT), weight-bearing behavioral testing, and histological inspections of the knee joint for evidence of structural changes in articular bone, cartilage and synovium. RESULTS: After 6 weeks, force discrepancies in weight-bearing distribution between the normal hind and postoperative limbs revealed superiority with high-dose TGF (18.00 ± 5.93 g) and celecoxib (18.68 ± 5.29 g) versus both ACLT alone (41.29 ± 7.06 g) and low-dose TGF (37.00 ± 7.40 g). Micro-CT images revealed that high-dose TGF and celecoxib similarly improved subchondral bone architecture, protected articular cartilage after ACLT, and downregulated proinflammatory cytokines interleukin-1ß and tumor necrosis factor-α in the cartilage and synovial sections. CONCLUSION: High-dose TGF induced the smallest amount of KOA-associated bone loss. Anti-inflammatory, anti-oxidative, and immunomodulatory effects of TGF were accompanied by reductions in proinflammatory cytokines and improvements in pain and function. TGF-induced anti-osteoporotic activity and inhibition of cartilage degradation were reflected by micro-CT and histological analysis. The findings help to explain how TGF alleviates symptoms of KOA.

Structural Insights into the Chaperone-Assisted Assembly of a Simplified Tail Fiber of the Myocyanophage Pam3.

At the first step of phage infection, the receptor-binding proteins (RBPs) such as tail fibers are responsible for recognizing specific host surface receptors. The proper folding and assembly of tail fibers usually requires a chaperone encoded by the phage genome. Despite extensive studies on phage structures, the molecular mechanism of phage tail fiber assembly remains largely unknown. Here, using a minimal myocyanophage, termed Pam3, isolated from Lake Chaohu, we demonstrate that the chaperone gp25 forms a stable complex with the tail fiber gp24 at a stoichiometry of 3:3. The 3.1-Å cryo-electron microscopy structure of this complex revealed an elongated structure with the gp25 trimer embracing the distal moieties of gp24 trimer at the center. Each gp24 subunit consists of three domains: the N-terminal α-helical domain required for docking to the baseplate, the tumor necrosis factor (TNF)-like and glycine-rich domains responsible for recognizing the host receptor. Each gp25 subunit consists of two domains: a non-conserved N-terminal ß-sandwich domain that binds to the TNF-like and glycine-rich domains of the fiber, and a C-terminal α-helical domain that mediates trimerization/assembly of the fiber. Structural analysis enabled us to propose the assembly mechanism of phage tail fibers, in which the chaperone first protects the intertwined and repetitive distal moiety of each fiber subunit, further ensures the proper folding of these highly plastic structural elements, and eventually enables the formation of the trimeric fiber. These findings provide the structural basis for the design and engineering of phage fibers for biotechnological applications.

The Traditional Chinese Medicine "Hu-Qian-Wan" Attenuates Osteoarthritis-Induced Signs and Symptoms in an Experimental Rat Model of Knee Osteoarthritis.

BACKGROUND: Knee osteoarthritis (KOA) is a chronic, low-grade inflammatory disease that affects knee joints and causes functional disability in the elderly. KOA is typically treated with oral NSAIDs, which are commonly associated with gastrointestinal side effects or cardiovascular complications. Traditional Chinese medicine (TCM) is widely used by patients with KOA in Taiwan; the Hu-Qian-Wan (HQW) formula is typically prescribed. We investigated the therapeutic role of a modified version of the HQW decoction in Sprague-Dawley rats with KOA induced by anterior cruciate ligament transection (ACLT) of the right knee. MATERIALS AND METHODS: Thirty rats were randomly assigned to five groups (six animals each): arthrotomy alone (sham surgery, controls), ACLT only, ACLT + low-dose (1,000 mg/kg) HQW, ACLT + high-dose (3,000 mg/kg) HQW, and ACLT + celecoxib (30 mg/kg). All study groups underwent weight-bearing behavioral testing, micro-computed tomography (CT), and histological examinations of the knee joint cartilage, as well as immunohistochemical analyses of levels of interleukin (IL) 1ß and tumor necrosis factor (TNF) α expression in articular cartilage. RESULTS: At 6 weeks, compared with ACLT group only, ACLT rats administered high-dose HQW or celecoxib exhibited the fewest weight-bearing deficits, the greatest improvements from baseline in articular cartilage architecture, and the lowest amounts of TNF-α and IL-1ß staining in cartilage and synovial sections (all values were significant compared with the ACLT-only group). The only values that were significantly increased by ACLT + low-dose HQW compared with ACLT alone were bone mineral density and trabecular numbers. CONCLUSION: Our findings suggest that high-dose HQW improves weight-bearing asymmetry, decreases bone loss, and reduces levels of TNF-α and IL-1ß in the affected joint in ACLT-induced KOA rats. More evidence is needed to support our findings.

Effects of Horseradish Oil and Eight Isothiocyanates Vapour Treatment on Postharvest Disease Control and Their Efficacy as Preservatives of Mature Green Tomato.

This study evaluated the potential of horseradish (Armoracia rusticana) oil (ARO) and eight isothiocyanates (propyl ITC [ProITC], isopropyl ITC [IsoproITC], n-butyl ITC [n-BuITC], 3-butenyl ITC [3-BeITC], phenyl ITC [PhITC], benzyl ITC [BzITC], 2-phenylethyl ITC [PhEITC], and allyl ITC [AITC]) as preservatives and antifungal agents for postharvest tomato disease control. Results showed that ARO and eight ITCs demonstrated antifungal activities against Botrytis cinerea, Alternaria alternata, Rhizopus stolonifer, and Geotrichum candidum, which can cause the decay of mature green tomato during storage. Allyl-ITC (AITC) had the lowest EC50 values of mycelia growth suppression, with 0.18, 0.44, 0.29, and 0.43 µg/ml air for B. cinerea, A. alternata, R. stolonifer, and G. candidum, respectively. ARO, 2-PhEITC, BzITC, and AITC exhibited better efficacy as preservatives of mature green tomato than other ITCs on the basis of some parameters, such as low decay rate, slow reduction in weight loss, slight change in hardness, slow decrease in acidity, and total soluble solid content of treated tomatoes. GC-MS revealed that 2-PhEITC (77.78%) and AITC (15.87%) were the major components of ARO. These results can be used as a basis to develop preservative products composed of ITCs.

A Crosslinked Soybean Protein Isolate Gel Polymer Electrolyte Based on Neutral Aqueous Electrolyte for a High-Energy-Density Supercapacitor.

A crosslinked membrane based on renewable, degradable and environmentally friendly soybean protein isolate was formed by solution casting method. A series of gel polymer electrolytes were prepared with the crosslinked membranes saturated with 1 mol·L-1 Li2SO4. The solid-state electric double-layer capacitors were fabricated with the prepared gel polymer electrolytes and activated carbon electrodes. The optimized solid-state supercapacitor delivered a single electrode specific capacitance of 115.17 F·g-1 at a current density of 1.0 A·g-1, which was higher than the supercapacitor assembled with the commercial separator in 1 mol·L-1 Li2SO4. The solid-state supercapacitor exhibited an outstanding cycling stability, indicating that the gel polymer electrolyte based on the crosslinked soybean protein isolate membrane could be a promising separator for a solid-state supercapacitor.

Commensal A4 bacteria inhibit intestinal Th2-cell responses through induction of dendritic cell TGF-ß production.

It has been shown that while commensal bacteria promote Th1, Th17 and Treg cells in lamina propria (LP) in steady-state conditions, they suppress mucosal Th2 cells. However, it is still unclear whether there are specific commensal organisms down-regulating Th2 responses, and the mechanism involved. Here we demonstrate that commensal A4 bacteria, a member of the Lachnospiraceae family, which produce an immunodominant microbiota CBir1 antigen, inhibits LP Th2-cell development. When transferred into the intestines of RAG(-/-) mice, CBir1-specific T cells developed predominately towards Th1 cells and Th17 cells, but to a lesser extent into Th2 cells. The addition of A4 bacterial lysates to CD4(+) T-cell cultures inhibited production of IL-4. A4 bacteria stimulated dendritic cell production of TGF-ß, and blockade of TGF-ß abrogated A4 bacteria inhibition of Th2-cell development in vitro and in vivo. Collectively, our data show that A4 bacteria inhibit Th2-cell differentiation by inducing dendritic cell production of TGF-ß.

Traditional Chinese medicine in patients with osteoarthritis of the knee.

To evaluate whether the use of traditional Chinese medicine (TCM; zhong yi) influences symptoms or functional outcomes in patients with osteoarthritis (OA) of the knee ( xi guan jié yán). A systematic review of randomized control trials was conducted. Searches for studies in PubMed that were performed between 1965 and August 2013, and retrieved studies were subjected to reference screening. The types of studies included in our review were 1) placebo-based or comparative studies; 2) open label, single-blinded or double-blinded studies; 3) studies evaluating the efficacy of TCM for treating OA of the knee; and 4) studies evaluating only TCM or combination preparations. Trials were conducted with participants over 18 years of age with knee pain and at least three of the following characteristics: 1) an age greater than 50 years; 2) morning stiffness lasting for fewer than 30 min; 3) a crackling or grating sensation; 4) bony tenderness of the knee; 5) bony enlargement of the knee; or 6) no detectable warmth of the joint to the touch. Studies were rated for risk of bias and graded for quality. After screening, 104 studies that satisfied the eligibility requirements were identified, and only 18 randomized control trials were included in the quantitative and qualitative synthesis. Upon review, we found "moderate-quality" evidence of effects from acupuncture ( zhen jiǔ) on pain, which was measured using a visual analogue scale, and physical function, which was measured using qigong ( qì gong) with motion. "Low-quality" evidence was found regarding the effects of acupuncture on physical function, and no evidence was found regarding the effects of herbal medicine on pain or physical function. Herbal patches ( yào bù) appeared to affect pain and physical and function, but these effects were not found to be significant. The initial findings included in this review suggest that acupuncture is a promising intervention according to the primary outcome measure, pain, and qigong with motion is an effective method for treating physical function. However, according to the Grades of Recommendation, Assessment, Development, and Evaluation criteria, only moderate-quality evidence was found in these studies. Further rigorous studies are warranted to investigate the application of TCM in treating OA of knee.

TGF-ß converts Th1 cells into Th17 cells through stimulation of Runx1 expression.

Differentiated CD4(+) T cells preserve plasticity under various conditions. However, the stability of Th1 cells is unclear, as is whether Th1 cells can convert into Th17 cells and thereby contribute to the generation of IFN-γ(+) IL-17(+) CD4(+) T cells, the number of which correlates with severity of colitis. We investigated whether IFN-γ(+) Th1 cells can convert into Th17 cells under intestinal inflammation and the mechanisms involved. IFN-γ(Thy1.1+) Th1 cells were generated by culturing naïve CD4(+) T cells from IFN-γ(Thy1.1) CBir1 TCR-Tg reporter mice, whose TCR is specific for an immunodominant microbiota antigen, CBir1 flagellin, under Th1 polarizing conditions. IFN-γ(Thy1.1+) Th1 cells induced colitis in Rag(-/-) mice after adoptive transfer and converted into IL-17(+) Th17, but not Foxp3(+) Treg cells in the inflamed intestines. TGF-ß and IL-6, but not IL-1ß and IL-23, regulated Th1 conversion into Th17 cells. TGF-ß induction of transcriptional factor Runx1 is crucial for the conversion, since silencing Runx1 by siRNA inhibited Th1 conversion into Th17 cells. Furthermore, TGF-ß enhanced histone H3K9 acetylation but inhibited H3K9 trimethylation of Runx1- and ROR-γt-binding sites on il-17 or rorc gene in Th1 cells. We conclude that Th1 cells convert into Th17 cells under inflammatory conditions in intestines, which is possibly mediated by TGF-ß induction of Runx1.

The History, Mechanism, and Clinical Application of Auricular Therapy in Traditional Chinese Medicine.

Auricular therapy includes acupuncture, electroacupuncture, acupressure, lasering, cauterization, moxibustion, and bloodletting in the auricle. For 2500 years, people have employed auricular therapy for treating diseases, but the methods have been limited to bloodletting and cauterization. Only after 1957, the international scientific community became aware that the map of the ear resembles an inverted fetus, its introduction has led to auricular acupuncture (AA) becoming a more systemic approach, and, following the identification and standardization of more precise points, AA has been employed in clinical applications. The mechanisms of AA are considered to have a close relationship with the autonomic nervous system, the neuroendocrine system, neuroimmunological factors, neuroinflammation, and neural reflex, as well as antioxidation. Auricular therapy has been applied, for example, for pain relief, for the treatment of epilepsy, anxiety, and obesity, and for improving sleep quality. However, the mechanisms and evidence for auricular therapy warrant further study.

[Learning curve of complete mesocolic excision for colon cancer].

OBJECTIVE: To evaluate the learning curve of complete mesocolic excision(CME) for colon cancer. METHODS: Clinical data of 75 cases in whom CME was performed by a group of surgeons in the Department of Gastrointestinal Surgery, Peking University People's Hospital from November 2009 to June 2011 were reviewed. The patients were divided into three groups(groups A, B, C, 25 cases in each group) by operative chronologic sequence. RESULTS: There were no significant differences in age, sex, preoperative staging, cancer location, operation history of abdomen, ASA among the three groups(P>0.05). The operative time in group A was (205.4 ± 53.2) min and decreased to (180.4 ± 29.7) min in group B and (169.8 ± 41.3) min in group C (P<0.05). The postoperative hospital stay decreased from (17.8 ± 10.9) d in group A to(12.9 ± 4.1) d in group B and(11.0 ± 3.5) d in group C(P<0.05). The postoperative complication rate decreased from 32%(8/25) in group A and 36%(9/25) to 8%(2/25) in group C. The specimen quality was superior in group C compared to group A (WEST grade C above were 20 and 11 respectively, P<0.05). There were no significant differences in intraoperative bleeding, time to first flatus, postoperative fasting time, number of retrieved lymph nodes among the three groups(P>0.05). CONCLUSION: From the learning curve of CME, surgeons can learn CME skill after performing 25 cases.

An integrated microfabricated cell sorter.

We have developed an integrated microfabricated cell sorter using multilayer soft lithography. This integrated cell sorter is incorporated with various microfluidic functionalities, including peristaltic pumps, dampers, switch valves, and input and output wells, to perform cell sorting in a coordinated and automated fashion. The active volume of an actuated valve on this integrated cell sorter can be as small as 1 pL, and the volume of optical interrogation is approximately 100 fL. Different algorithms of cell manipulation, including cell trapping, were implemented in these devices. We have also demonstrated sorting and recovery of Escherichia coli cells on the chip.