Natural anti-HIV agents-part I: (+)-demethoxyepiexcelsin and verticillatol from Litsea verticillata

The eudesmane sesquiterpenoid, verticillatol (1), as well as the lignan, (+)-5'-demethoxyepiexcelsin (2), and a known lignan, (+)-epiexcelsin (3), were isolated from Litsea verticillata Hance. Lignan 2 showed moderate anti-HIV activity with an IC(50) value of 16.4 microg/ml (42.7 microM), while the known lignan 3 was inactive up to a concentration of 20 microg/ml (48.3 microM). Compound 1 demonstrated weak activity with an IC(50) value of 34.5 microg/ml (144.7 microM) while being devoid of cytotoxicity at 20 microg/ml. The structures were elucidated by 1D and 2D NMR spectroscopy, and the absolute configuration of the new sesquiterpenoid was determined by the generation of Mosher esters.     

Development of Sjogren's syndrome in nonobese diabetic-derived autoimmune-prone C57BL/6.NOD-Aec1Aec2 mice is dependent on complement component-3

The role of complement in the etiology of Sj?gren's syndrome (SjS), a human autoimmune disease manifested primarily by salivary and lacrimal gland dysfunction resulting in dry mouth/dry eye syndrome, remains ill-defined. In the present study, we examined the role of complement component-3 (C3) using a newly constructed C3-gene knockout mouse, C57BL/6.NOD-Aec1Aec2.C3(-/-). Inactivation of C3 in the parental C57BL/6.NOD-Aec1Aec2 strain, a model of primary SjS, resulted in a diminished or total absence of both preclinical and clinical manifestations during development and onset of disease, including reduced acinar cell apoptosis, reduced levels of caspase-3, lack of leukocyte infiltration of submandibular glands, reduced synthesis of disease-associated autoantibodies, maintenance of normal glandular architecture, and retention of normal saliva secretion. In addition, C57BL/6-NOD.Aec1Aec2.C3(-/-) mice did not exhibit increased numbers of marginal zone B cells, a feature of SjS-prone C57BL/6-NOD.Aec1Aec2 mice. Interestingly, C57BL/6-NOD.Aec1Aec2.C3(-/-) mice retained some early pathological manifestations, including activation of serine kinases with proteolytic activity for parotid secretory protein. This improvement in the clinical manifestations of SjS-like disease in C57BL/6.NOD-Aec1Aec2.C3(-/-) mice, apparently a direct consequence of C3 deficiency, supports a much more important role for complement in the adaptive autoimmune response than previously recognized, possibly implicating an essential role for innate immunity.     

Impact of Nitrogen Fertilizer on the Mycorrhizal Inoculating Potential and Fungal Community Structure in Rhizosphere of Medicinal Plant Curcuma longa L.

Reducing chemical fertilizer while remaining high crop yield has become a trend of agricultural practice. The purpose of this study was to investigate the effects of nitrogen (N) input on the structure of the fungal community and mycorrhizal inoculum potential in rhizosphere of Curcuma longa, aiming to minimize the use of chemicals and optimize the effect of biofertilizer for sustainable turmeric farming. For this, a field study was conducted in two successive years 2015 and 2016 with applications of varrying N fertilizer rates N0 (0 kgN ha^?1 y^?1), N150 (150 kgN ha^?1 y^?1), N350 (350 kgN ha^?1 y^?1), and N500 (500 kgN ha^?1 y^?1) in combination with mycorrhizal biofertilizer on turmeric plants in Hung-Yen. Rhizosphere soils were then analyzed for the abundance of predominant fungal taxon based on amplicon sequencing of rDNA internal transcribed spacer regions. Metagenomic results indicated significant effects of N inputs on rhizosphere fungal communities composition, with dominance of ascomyceteous fungi under optimized N levels, whereas basidiomycetous fungi were more abundant under higher N input. Operational taxonomic units relating to the predominantly abundant genus Glomus were found apparently in higher proportion under optimized N inputs (N150). The results demonstrate an enhanced productivity and icreased mycorrhizal inoculating potential by appropriated N fertilizer application in turmeric rhizosphere.     

Selenium nanoparticles as in vitro rooting agent,regulates stomata closure and antioxidant activity of gerbera to tolerate acclimatization stress

Plant Cell, Tissue and Organ Culture (PCTOC) - The acclimatization stress is responsible for high mortality in tissue cultured plants, which significantly reduces micropropagation efficiency. In...     

High Levels of Antimicrobial Resistance among Escherichia coli Isolates from Livestock Farms and Synanthropic Rats and Shrews in the Mekong Delta of Vietnam

In Mekong Delta farms (Vietnam), antimicrobials are extensively used, but limited data are available on levels of antimicrobial resistance (AMR) among Escherichia coli isolates. We performed a structured survey of AMR in E. coli isolates (n = 434) from 90 pig, chicken, and duck farms. The results were compared with AMR among E. coli isolates (n = 234) from 66 small wild animals (rats and shrews) trapped on farms and in forests and rice fields. The isolates were susceptibility tested against eight antimicrobials. E. coli isolates from farmed animals were resistant to a median of 4 (interquartile range [IQR], 3 to 6) antimicrobials versus 1 (IQR, 1 to 2) among wild mammal isolates (P < 0.001). The prevalences of AMR among farmed species isolates (versus wild animals) were as follows: tetracycline, 84.7% (versus 25.6%); ampicillin, 78.9% (versus 85.9%); trimethoprim-sulfamethoxazole, 52.1% (versus 18.8%); chloramphenicol, 39.9% (versus 22.5%); amoxicillin-clavulanic acid, 36.6% (versus 34.5%); and ciprofloxacin, 24.9% (versus 7.3%). The prevalence of multidrug resistance (MDR) (resistance against three or more antimicrobial classes) among pig isolates was 86.7% compared to 66.9 to 72.7% among poultry isolates. After adjusting for host species, MDR was ∼8 times greater among isolates from wild mammals trapped on farms than among those trapped in forests/rice fields (P < 0.001). Isolates were assigned to unique profiles representing their combinations of susceptibility results. Multivariable analysis of variance indicated that AMR profiles from wild mammals trapped on farms and those from domestic animals were more alike (R² range, 0.14 to 0.30) than E. coli isolates from domestic animals and mammals trapped in the wild (R² range, 0.25 to 0.45). The results strongly suggest that AMR on farms is a key driver of environmental AMR in the Mekong Delta.     

Molecular and Biological Characterization of Potato virus Y Isolates from Vietnam

Eight isolates from different potato growing regions in Vietnam were characterized. All were highly pathogenic in some potato cultivars, but did not overcome the extreme resistance of Solanum stoloniferum and Solanum demissum. RT‐PCR analysis revealed that all of these isolates are recombinants. Sequence data for 4 isolates were obtained, and their reaction in potato cultivars harbouring specific N genes was determined. Different phylogenetic analyses of viral sequences confirmed previous results that the recombinant isolates evolved from different parental sequences. One of the Vietnamese isolates investigated had a specific structure. The need for a clear classification of PVY^NWi isolates is discussed.     

High Treatment Retention Rate in HIV-Infected Patients Receiving Antiretroviral Therapy at Two Large HIV Clinics in Hanoi,Vietnam

Background

Loss to follow-up (LTFU) is viewed as a major challenge in improving retention in HIV treatment. In Vietnam, the reasons for disengagement from clinics and the effect of injection drug use (IDU) on LTFU with unknown outcome (true LTFU) are not well known.

Methods

Patients receiving antiretroviral therapy (ART) from two HIV clinics in Hanoi were included in this observational study between 2007 and 2012, and followed up every 6 months until the end of 2013. The reasons for disengagement from the clinic, and ART status during imprisonment were investigated in patients with a history of IDU to identify true LTFU. The retention rate at 6–54 months and true LTFU rate were calculated. Cox proportional hazards regression models were performed to identify factors associated with true LTFU.

Results

There were 1,431 patients, with a follow-up time of 4,371 person-years (median 2.49 years). At the end of the follow-up period, 71 (5.0%) patients died, 79 (5.5%) transferred to other clinics, 16 (1.1%) disengaged from the clinics, and the calculated true LTFU was 45 (3.1%), with 12-month ART retention rate of 95.3% for the entire study population. Imprisonment was the most frequent reason for disengagement from the clinics. True LTFU correlated significantly with low CD4 count and high plasma viral load, but not history of IDU.

Conclusion

Imprisonment is a major cause of disengagement from HIV care among patients with a history of IDU.     

Confounding factors in HGT detection: statistical error, coalescent effects, and multiple solutions.

Prokaryotic organisms share genetic material across species boundaries by means of a process known as horizontal gene transfer (HGT). This process has great significance for understanding prokaryotic genome diversification and unraveling their complexities. Phylogeny-based detection of HGT is one of the most commonly used methods for this task, and is based on the fundamental fact that HGT may cause gene trees to disagree with one another, as well as with the species phylogeny. Using these methods, we can compare gene and species trees, and infer a set of HGT events to reconcile the differences among these trees. In this paper, we address three factors that confound the detection of the true HGT events, including the donors and recipients of horizontally transferred genes. First, we study experimentally the effects of error in the estimated gene trees (statistical error) on the accuracy of inferred HGT events. Our results indicate that statistical error leads to overestimation of the number of HGT events, and that HGT detection methods should be designed with unresolved gene trees in mind. Second, we demonstrate, both theoretically and empirically, that based on topological comparison alone, the number of HGT scenarios that reconcile a pair of species/gene trees may be exponential. This number may be reduced when branch lengths in both trees are estimated correctly. This set of results implies that in the absence of additional biological information, and/or a biological model of how HGT occurs, multiple HGT scenarios must be sought, and efficient strategies for how to enumerate such solutions must be developed. Third, we address the issue of lineage sorting, how it confounds HGT detection, and how to incorporate it with HGT into a single stochastic framework that distinguishes between the two events by extending population genetics theories. This result is very important, particularly when analyzing closely related organisms, where coalescent effects may not be ignored when reconciling gene trees. In addition to these three confounding factors, we consider the problem of enumerating all valid coalescent scenarios that constitute plausible species/gene tree reconciliations, and develop a polynomial-time dynamic programming algorithm for solving it. This result bears great significance on reducing the search space for heuristics that seek reconciliation scenarios. Finally, we show, empirically, that the locality of incongruence between a pair of trees has an impact on the numbers of HGT and coalescent reconciliation scenarios.     

A simplified and robust protocol for immunoglobulin expression in Escherichia coli cell‐free protein synthesis systems

Cell‐free protein synthesis (CFPS) systems allow for robust protein expression with easy manipulation of conditions to improve protein yield and folding. Recent technological developments have significantly increased the productivity and reduced the operating costs of CFPS systems, such that they can compete with conventional in vivo protein production platforms, while also offering new routes for the discovery and production of biotherapeutics. As cell‐free systems have evolved, productivity increases have commonly been obtained by addition of components to previously designed reaction mixtures without careful re‐examination of the essentiality of reagents from previous generations. Here we present a systematic sensitivity analysis of the components in a conventional Escherichia coli CFPS reaction mixture to evaluate their optimal concentrations for production of the immunoglobulin G trastuzumab. We identify eight changes to the system, which result in optimal expression of trastuzumab. We find that doubling the potassium glutamate concentration, while entirely eliminating pyruvate, coenzyme A, NAD, total tRNA, folinic acid, putrescine and ammonium glutamate, results in a highly productive cell‐free system with a 95% reduction in reagent costs (excluding cell‐extract, plasmid, and T7 RNA polymerase made in‐house). A larger panel of other proteins was also tested and all show equivalent or improved yields with our simplified system. Furthermore, we demonstrate that all of the reagents for CFPS can be combined in a single freeze‐thaw stable master mix to improve reliability and ease of use. These improvements are important for the application of the CFPS system in fields such as protein engineering, high‐throughput screening, and biotherapeutics. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:823–831, 2015