A Peptide Bond from the Inter-lobe Segment in the Bilobal Lactoferrin Acts as a Preferred Site for Cleavage for Serine Proteases to Generate the Perfect C-lobe: Structure of the Pepsin Hydrolyzed Lactoferrin C-lobe at 2.28 Å Resolution

The Protein Journal - C-lobe represents the C-terminal half of lactoferrin which is a bilobal 80 kDa iron binding glycoprotein. The two lobes are designated as N-lobe (Ser1-Glu333) and...     

Sequential interactions of silver–silica nanocomposite (Ag–SiO2NC) with cell wall,metabolism and genetic stability of Pseudomonas aeruginosa,a multiple antibiotic‐resistant bacterium

The study was carried out to understand the effect of silver–silica nanocomposite (Ag–SiO₂NC) on the cell wall integrity, metabolism and genetic stability of Pseudomonas aeruginosa, a multiple drug‐resistant bacterium. Bacterial sensitivity towards antibiotics and Ag–SiO₂NC was studied using standard disc diffusion and death rate assay, respectively. The effect of Ag–SiO₂NC on cell wall integrity was monitored using SDS assay and fatty acid profile analysis, while the effect on metabolism and genetic stability was assayed microscopically, using CTC viability staining and comet assay, respectively. Pseudomonas aeruginosa was found to be resistant to β‐lactamase, glycopeptidase, sulfonamide, quinolones, nitrofurantoin and macrolides classes of antibiotics. Complete mortality of the bacterium was achieved with 80 μg ml^?1 concentration of Ag–SiO₂NC. The cell wall integrity reduced with increasing time and reached a plateau of 70% in 110 min. Changes were also noticed in the proportion of fatty acids after the treatment. Inside the cytoplasm, a complete inhibition of electron transport system was achieved with 100 μg ml^?1 Ag–SiO₂NC, followed by DNA breakage. The study thus demonstrates that Ag–SiO₂NC invades the cytoplasm of the multiple drug‐resistant P. aeruginosa by impinging upon the cell wall integrity and kills the cells by interfering with electron transport chain and the genetic stability.

Significance and Impact of Study

Although the synthesis, structural characteristics and biofunction of silver nanoparticles are well understood, their application in antimicrobial therapy is still at its infancy as only a small number of microorganisms are tested to be sensitive to nanoparticles. A thorough knowledge of the mode of interaction of nanoparticles with bacteria at subcellular level is mandatory for any clinical application. The present study deals with the interactions of Ag–SiO2NC with the cell wall integrity, metabolism and genetic stability of Pseudomonas aeruginosa, which would contribute substantially in strengthening the therapeutic applications of silver nanoparticles.     

Recombinant Murine Gamma Herpesvirus 68 Carrying KSHV G Protein-Coupled Receptor Induces Angiogenic Lesions in Mice

Human gamma herpesviruses, including Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), are capable of inducing tumors, particularly in in immune-compromised individuals. Due to the stringent host tropism, rodents are resistant to infection by human gamma herpesviruses, creating a significant barrier for the in vivo study of viral genes that contribute to tumorigenesis. The closely-related murine gamma herpesvirus 68 (γHV68) efficiently infects laboratory mouse strains and establishes robust persistent infection without causing apparent disease. Here, we report that a recombinant γHV68 carrying the KSHV G protein-coupled receptor (kGPCR) in place of its murine counterpart induces angiogenic tumors in infected mice. Although viral GPCRs are conserved in all gamma herpesviruses, kGPCR potently activated downstream signaling and induced tumor formation in nude mouse, whereas γHV68 GPCR failed to do so. Recombinant γHV68 carrying kGPCR demonstrated more robust lytic replication ex vivo than wild-type γHV68, although both viruses underwent similar acute and latent infection in vivo. Infection of immunosuppressed mice with γHV68 carrying kGPCR, but not wild-type γHV68, induced tumors in mice that exhibited angiogenic and inflammatory features shared with human Kaposi’s sarcoma. Immunohistochemistry staining identified abundant latently-infected cells and a small number of cells supporting lytic replication in tumor tissue. Thus, mouse infection with a recombinant γHV68 carrying kGPCR provides a useful small animal model for tumorigenesis induced by a human gamma herpesvirus gene in the setting of a natural course of infection.     

EP-1 不育剂对长爪沙鼠野生种群增长的控制作用

长爪沙鼠在内蒙古地区的分布非常广泛,长期以来由其造成的“鼠害” 不仅给农牧业生产带来危害,而且还传播疾病。2009 年3 ～ 10 月,在内蒙古鄂尔多斯荒漠草原,利用复合不育剂左炔诺孕酮- 炔雌醚(EP-1)
对长爪沙鼠野生种群进行了不育控制试验研究。结果表明,复合不育剂EP-1 对长爪沙鼠种群结构和种群密度均有显著影响,在5 月和6 月两个繁殖高峰期,不育剂EP-1 显著降低了幼体出生的数量,实验区与对照区幼体组
成差异和成体组成差异均达到极显著(P < 0.01)。在8 ～ 10 月,实验区和对照区种群结构组成中,幼体之间、成体之间差异均达到显著和极显著(P < 0.05, P < 0.01)。在整个发育生长期,实验区长爪沙鼠幼体种群从6 月
份开始出现,9 月达到数量最高值,幼体种群全年呈现下降趋势。而对照区幼体种群从5 月份开始出现,且数量在5 月份达到全年的最高值,幼体种群与实验区相反呈增长趋势。实验区种群总体数量全年呈下降趋势,而对
照区相反,呈增长趋势。因此,复合不育剂EP-1 显著降低了长爪沙鼠种群的繁殖率、幼体出生比例和种群密度,可以对长爪沙鼠野生种群起到有效的繁殖控制作用,进而降低该鼠对农牧业生产的危害和对人类疾病传播
的风险。     

Functional compensation between hematopoietic stem cell clones in vivo

In most organ systems, regeneration is a coordinated effort that involves many stem cells, but little is known about whether and how individual stem cells compensate for the differentiation deficiencies of other stem cells. Functional compensation is critically important during disease progression and treatment. Here, we show how individual hematopoietic stem cell (HSC) clones heterogeneously compensate for the lymphopoietic deficiencies of other HSCs in a mouse. This compensation rescues the overall blood supply and influences blood cell types outside of the deficient lineages in distinct patterns. We find that highly differentiating HSC clones expand their cell numbers at specific differentiation stages to compensate for the deficiencies of other HSCs. Some of these clones continue to expand after transplantation into secondary recipients. In addition, lymphopoietic compensation involves gene expression changes in HSCs that are characterized by increased lymphoid priming, decreased myeloid priming, and HSC self‐renewal. Our data illustrate how HSC clones coordinate to maintain the overall blood supply. Exploiting the innate compensation capacity of stem cell networks may improve the prognosis and treatment of many diseases.     

Effect of Short-Term Supplementation with Ready-to-Use Therapeutic Food or Micronutrients for Children after Illness for Prevention of Malnutrition: A Randomised Controlled Trial in Nigeria

Background

Globally, Médecins Sans Frontières (MSF) treats more than 300,000 severely malnourished children annually. Malnutrition is not only caused by lack of food and poor infant and child feeding practices but also by illnesses. Breaking the vicious cycle of illness and malnutrition by providing ill children with nutritional supplementation is a potentially powerful strategy for preventing malnutrition that has not been adequately investigated. Therefore, MSF investigated whether incidence of malnutrition among ill children <5 y old could be reduced by providing a fortified food product or micronutrients during their 2-wk convalescence period. Two trials, one in Nigeria and one in Uganda, were conducted; here we report on the trial that took place in Goronyo, a rural region of northwest Nigeria with high morbidity and malnutrition rates.

Methods and Findings

We investigated the effect of supplementation with ready-to-use therapeutic food (RUTF) and a micronutrient powder (MNP) on the incidence of malnutrition in ill children presenting at an outpatient clinic in Goronyo during February to September 2012. A three-armed, partially-blinded, randomised controlled trial was conducted in children diagnosed as having malaria, diarrhoea, or lower respiratory tract infection. Children aged 6 to 59 mo were randomised to one of three arms: one sachet/d of RUTF; two sachets/d of micronutrients or no supplement (control) for 14 d for each illness over 6 mo. The primary outcome was the incidence of first negative nutritional outcome (NNO) during the 6 mo follow-up. NNO was a study-specific measure used to indicate occurrence of malnutrition; it was defined as low weight-for-height z-score (<−2 for non-malnourished and <−3 for moderately malnourished children), mid-upper arm circumference <115 mm, or oedema, whichever came first.Of the 2,213 randomised participants, 50.0% were female and the mean age was 20.2 (standard deviation 11.2) months; 160 (7.2%) were lost to follow-up, 54 (2.4%) were admitted to hospital, and 29 (1.3%) died. The incidence rates of NNO for the RUTF, MNP, and control groups were 0.522 (95% confidence interval (95% CI), 0.442–0.617), 0.495 (0.415–0.589), and 0.566 (0.479–0.668) first events/y, respectively. The incidence rate ratio was 0.92 (95% CI, 0.74–1.15; p = 0.471) for RUTF versus control; 0.87 (0.70–1.10; p = 0.242) for MNP versus control and 1.06 (0.84–1.33, p = 0.642) for RUTF versus MNP. A subgroup analysis showed no interaction nor confounding, nor a different effectiveness of supplementation, among children who were moderately malnourished compared with non-malnourished at enrollment. The average number of study illnesses for the RUTF, MNP, and control groups were 4.2 (95% CI, 4.0–4.3), 3.4 (3.2–3.6), and 3.6 (3.4–3.7). The proportion of children who died in the RUTF, MNP, and control groups were 0.8% (95% CI, 0.3–1.8), 1.8% (1.0–3.3), and 1.4% (0.7–2.8).

Conclusions

A 2-wk supplementation with RUTF or MNP to ill children as part of routine primary medical care did not reduce the incidence of malnutrition. The lack of effect in Goronyo may be due to a high frequency of morbidity, which probably further affects a child’s nutritional status and children’s ability to escape from the illness–malnutrition cycle. The duration of the supplementation may have been too short or the doses of the supplements may have been too low to mitigate the effects of high morbidity and pre-existing malnutrition. An integrated approach combining prevention and treatment of diseases and treatment of moderate malnutrition, rather than prevention of malnutrition by nutritional supplementation alone, might be more effective in reducing the incidence of acute malnutrition in ill children.

Trial Registration

clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01154803","term_id":"NCT01154803"}}NCT01154803     

UV-absorbing bacteria in coral mucus and their response to simulated temperature elevations

Reef-building corals encompass various strategies to defend against harmful ultraviolet (UV) radiation. Coral mucus contains UV-absorbing compounds and has rich prokaryotic diversity associated with it. In this study, we isolated and characterized the UV-absorbing bacteria from the mucus of the corals Porites lutea and Acropora hyacinthus during the pre-summer and summer seasons. A total of 17 UV-absorbing bacteria were isolated and sequenced. The UV-absorbing bacteria showed UV absorption at wavelengths ranging from λ _max = 333 nm to λ _min = 208 nm. Analysis of the DNA sequences revealed that the majority of the UV-absorbing bacteria belonged to the family Firmicutes and the remaining belonged to the family Proteobacteria (class Gammaproteobacteria). Comparison of the sequences with the curated database yielded four distinct bacterial groups belonging to the genus Bacillus, Staphylococcus, Salinicoccus and Vibrio. The absorption peaks for the UV-absorbing bacteria shifted to the UV-A range (320–400 nm) when they were incubated at higher temperatures. Deciphering the complex relationship between corals and their associated bacteria will help us to understand their adaptive strategies to various stresses.     

Glutaraldehyde modified mica: a new surface for atomic force microscopy of chromatin

We have found that mica surfaces functionalized with aminopropyltriethoxysilane and aldehydes bind chromatin strongly enough to permit stable and reliable solution imaging by atomic force microscopy. The method is highly reproducible, uses very small amounts of material, and is successful even with very light degrees of surface modification. This surface is far superior to the widely used aminopropyltriethoxysilane-derivatized mica surface and permits resolution of structure on the nanometer-scale in an aqueous environment, conditions that are particularly important for chromatin studies. For example, bound nucleosomal arrays demonstrate major structural changes in response to changes in solution conditions, despite their prior fixation (to maintain nucleosome loading) and tethering to the surface with glutaraldehyde. By following individual molecules through a salt titration in a flow-through cell, one can observe significant changes in apparent nucleosome size at lower [salt] and complete loss of DNA from the polynucleosomal array at high salt. The latter result demonstrates that the DNA component in these arrays is not constrained by the tethering. The former result is consistent with the salt-induced loss of histones observed in bulk solution studies of chromatin and demonstrates that even histone components of the nucleosome are somewhat labile in these fixed and tethered arrays. We foresee many important applications for this surface in future atomic force microscopy studies of chromatin.     

Genomics in Neurological Disorders

Neurological disorders comprise a variety of complex diseases in the central nervous system, which can be roughly classified as neurodegenerative diseases and psychiatric disorders. The basic and translational research of neurological disorders has been hindered by the difficulty in accessing the pathological center （i.e., the brain） in live patients. The rapid advancement of sequencing and array technologies has made it possible to investigate the disease mechanism and biomarkers from a systems perspective. In this review, recent progresses in the discovery of novel risk genes, treatment targets and peripheral biomarkers employing genomic technologies will be dis- cussed. Our major focus will be on two of the most heavily investigated neurological disorders, namely Alzheimer＇s disease and autism spectrum disorder.     

Epidemiological and entomological evaluations after six years or more of mass drug administration for lymphatic filariasis elimination in Nigeria

The current strategy for interrupting transmission of lymphatic filariasis (LF) is annual mass drug administration (MDA), at good coverage, for 6 or more years. We describe our programmatic experience delivering the MDA combination of ivermectin and albendazole in Plateau and Nasarawa states in central Nigeria, where LF is caused by anopheline transmitted Wuchereria bancrofti. Baseline LF mapping using rapid blood antigen detection tests showed mean local government area (LGA) prevalence of 23% (range 4-62%). MDA was launched in 2000 and by 2003 had been scaled up to full geographic coverage in all 30 LGAs in the two states; over 26 million cumulative directly observed treatments were provided by community drug distributors over the intervention period. Reported treatment coverage for each round was ≥85% of the treatment eligible population of 3.7 million, although a population-based coverage survey in 2003 showed lower coverage (72.2%; 95% CI 65.5-79.0%). To determine impact on transmission, we monitored three LF infection parameters (microfilaremia, antigenemia, and mosquito infection) in 10 sentinel villages (SVs) serially. The last monitoring was done in 2009, when SVs had been treated for 7-10 years. Microfilaremia in 2009 decreased by 83% from baseline (from 4.9% to 0.8%); antigenemia by 67% (from 21.6% to 7.2%); mosquito infection rate (all larval stages) by 86% (from 3.1% to 0.4%); and mosquito infectivity rate (L3 stages) by 76% (from 1.3% to 0.3%). All changes were statistically significant. Results suggest that LF transmission has been interrupted in 5 of the 10 SVs, based on 2009 finding of microfilaremia ≥1% and/or L3 stages in mosquitoes. Four of the five SVs where transmission persists had baseline antigenemia prevalence of >25%. Longer or additional interventions (e.g., more frequent MDA treatments, insecticidal bed nets) should be considered for 'hot spots' where transmission is ongoing.