Spirulan from Blue‐Green Algae Inhibits Fibrin and Blood Clots: Its Potent Antithrombotic Effects

We investigated in vitro and in vivo fibrinolytic and antithrombotic activity of spirulan and analyzed its partial biochemical properties. Spirulan, a sulfated polysaccharide from the blue‐green alga Arthrospira platensis, exhibits antithrombotic potency. Spirulan showed a strong fibrin zymogram lysis band corresponding to its molecular mass. It specifically cleaved Aα and Bβ, the major chains of fibrinogen. Spirulan directly decreased the activity of thrombin and factor X activated (FXa), procoagulant proteins. In vitro assays using human fibrin and mouse blood clots showed fibrinolytic and hemolytic activities of spirulan. Spirulan (2 mg/kg) showed antithrombotic effects in the ferric chloride (FeCl₃)‐induced carotid arterial thrombus model and collagen and epinephrine‐induced pulmonary thromboembolism mouse model. These results may be attributable to the prevention of thrombus formation and partial lysis of thrombus. Therefore, we suggest that spirulan may be a potential antithrombotic agent for thrombosis‐related diseases.     

小叶锦鸡儿灌丛下土壤水分对降雨的响应

以科尔沁沙地主要固沙灌木小叶锦鸡儿为研究对象,在其生长季次降雨21.5 mm后180 h内,利用TDR和微渗仪测量小叶锦鸡儿灌丛下不同部位的土壤含水量和土壤蒸发,并计算该灌丛下不同部位储水量和水量平衡.结果表明:降雨结束后初期,灌丛枝干的茎流作用使其根部的土壤含水量明显高于其他部位;灌丛根部水分的入渗速率大于灌丛中部和灌丛外缘.因冠幅的庇荫作用,灌丛下蒸发量小于灌丛外裸露沙地.水量平衡表明:小叶锦鸡儿灌丛下降雨后前期蒸散量明显高于灌丛外裸露沙地,与灌丛下根系的分布有直接关系.     

Catalytic antibodies: balancing between Dr. Jekyll and Mr. Hyde

The immunoglobulin molecule is a perfect template for the de novo generation of biocatalytic functions. Catalytic antibodies, or abzymes, obtained by the structural mimicking of enzyme active sites have been shown to catalyze numerous chemical reactions. Natural enzyme analogs for some of these reactions have not yet been found or possibly do not exist at all. Nowadays, the dramatic breakthrough in antibody engineering and expression technologies has promoted a considerable expansion of immunoglobulin's medical applications and is offering abzymes a unique chance to become a promising source of high‐precision “catalytic vaccines.” At the same time, the discovery of natural abzymes on the background of autoimmune disease revealed their beneficial and pathogenic roles in the disease progression. Thus, the conflicting Dr. Jekyll and Mr. Hyde protective and destructive essences of catalytic antibodies should be carefully considered in the development of therapeutic abzyme applications.     

Development of the infant intestinal microbiome: A bird's eye view of a complex process

Infants undergo profound shifts in colonizing intestinal microorganisms during their first year, especially during and after birth and during weaning. Microbiota are passed to infants through the placenta, during the vaginal birth process, and from early diet and other environmental exposures. These microbiota play an active role in the development of healthy infant metabolic and immunologic systems; profound shifts in microbiotal populations can be persistent, are associated with immediate alterations in gene expression, metabolic, immunologic, and neurologic function, and with downstream metabolic and immunologic consequences such as obesity, allergies, asthma, autoimmune diseases, and potentially neurologic conditions. Many modern exposures, including Cesarean section, formula feeding, and antibiotics, have been associated with microbiome shifts, and also with downstream diseases; while many published studies considered exposures individually, a more comprehensive understanding of their interaction and impact will consider the entirety of the infant's environment. It is not possible, nor desirable, to return to a world without toilets, sewers, tap water, delivery room antisepsis, Cesarean sections, antibiotics, immunizations, and refrigerators; our other alternative is to better understand these complex changes in infant developmental and molecular physiology. Protecting and repairing the developmental processes of the healthy infant microbiome is the modern medical frontier. Birth Defects Research (Part C) 105:228–239, 2015. © 2015 Wiley Periodicals, Inc.     

Weekly administration of rapamycin improves survival and biomarkers in obese male mice on high‐fat diet

Recent discoveries have revealed the key role of mTOR (target of rapamycin) in aging. Furthermore, rapamycin extends lifespan in mice, especially in female mice. Here, we treated obese male mice on high‐fat diet with rapamycin given intermittently: either weekly (once a week) or alternating bi‐weekly (three injections every other week). While only marginally reducing obesity, intermittent administration of rapamycin significantly extended lifespan. Significance was achieved for weekly treated group and for the three rapamycin‐received groups combined. In weekly treatment group, 100% mice were alive by the age of 2 years, whereas 60% of mice died in untreated group by this age. The effect of weekly treatment on survival was highly significant and cannot be fully explained by partial reduction in obesity. Alternating bi‐weekly treatments seem to be less effective than weekly treatment, although effects of additional factors (see 3 ) may not be excluded. After one year of treatment, all survived mice were sacrificed 8 days after the last administration of rapamycin to avoid its direct interference with parameters examined. Fasting levels of cardiac and hepatic p‐S6, a marker of mTORC1 activity, were lower in weekly treatment group compared with control mice. In contrast, levels of p‐Akt (S473), glucose, triglycerides and insulin were unchanged, whereas leptin and IGF‐1 tended to be lower. Thus, weekly treatment with rapamycin may slow down aging in obese male mice on high‐fat diet.     

Heritability of anti‐predatory traits: vigilance and locomotor performance in marmots

Animals must allocate some proportion of their time to detecting predators. In birds and mammals, such anti‐predator vigilance has been well studied, and we know that it may be influenced by a variety of intrinsic and extrinsic factors. Despite hundreds of studies focusing on vigilance and suggestions that there are individual differences in vigilance, there have been no prior studies examining its heritability in the field. Here, we present one of the first reports of (additive) genetic variation in vigilance. Using a restricted maximum likelihood procedure, we found that, in yellow‐bellied marmots (Marmota flaviventris), the heritability of locomotor ability (h² = 0.21), and especially vigilance (h² = 0.08), is low. These modest heritability estimates suggest great environmental variation or a history of directional selection eliminating genetic variation in these traits. We also found a significant phenotypic (r_P = ?0.09 ± 0.04, P = 0.024) and a substantial, but not significant, genetic correlation (r_A = ?0.57 ± 0.28, P = 0.082) between the two traits (slower animals are less vigilant while foraging). We found no evidence of differential survival or longevity associated with particular phenotypes of either trait. The genetic correlation may persist because of environmental heterogeneity and genotype‐by‐environment interactions maintaining the correlation, or because there are two ways to solve the problem of foraging in exposed areas: be very vigilant and rely on early detection coupled with speed to escape, or reduce vigilance to minimize time spent in an exposed location. Both strategies seem to be equally successful, and this ‘locomotor ability‐wariness’ syndrome may therefore allow slow animals to compensate behaviourally for their impaired locomotor ability.     

Disentangling Relations among Repertoire Size,Song Rate,Signal Redundancy and Ambient Noise Level in European Songbird

The majority of male songbirds have small repertoires and sing with eventual variety; that is, they present one song type several times before switching to the next one. Several hypotheses have been proposed to explain this phenomenon. The antiexhaustion hypothesis argues that song‐type switching prevents muscle fatigue in the syrinx. The signal redundancy hypothesis suggests that repeating the same signal increases transmission success. Here, we have studied the song behaviour of the chaffinch, Fringilla coelebs, a common Eurasian species in which the males sing a few different song types and provide eventual variety. We tested different hypotheses to explain the temporal organisation of song output (repertoire size, song rate, bout duration, etc.) as a function of ambient noise by comparing birds from the same macrogeographic region in which the birds live either in a noisy town (n = 71) or in a quieter forest habitat (n = 68). Contrary to the prediction of the signal redundancy hypothesis and the results of earlier work on chaffinches living close to noisy streams, we found no significant differences in song characteristics between the town and forest populations. Our results support the antiexhaustion hypothesis because males with larger repertoires were able to sing with a significantly higher rate due to faster switching between different song types and producing shorter bouts. Sample size or population differences between our study and earlier investigations of the same species may explain the inconsistency with previous findings. Future studies should focus on determining the relations between song organisation and the directly measured quality of males and females' choice using, preferably, a longitudinal approach.     

Structural insights of Mycobacterium GTPase‐Obg and anti‐sigma‐F factor Usfx interaction

An essential protein for bacterial growth, GTPase‐Obg (Obg), is known to play an unknown but crucial role in stress response as its expression increases in Mycobacterium under stress conditions. It is well reported that Obg interacts with anti‐sigma‐F factor Usfx; however, a detailed analysis and structural characterization of their physical interaction remain undone. In view of above‐mentioned points, this study was conceptualized for performing binding analysis and structural characterization of Obg‐Usfx interaction. The binding studies were performed by surface plasmon resonance, while in silico docking analysis was done to identify crucial residues responsible for Obg‐Usfx interaction. Surface plasmon resonance results clearly suggest that N‐terminal and G domains of Obg mainly contribute to Usfx binding. Also, binding constants display strong affinity that was further evident by intermolecular hydrogen bonds and hydrophobic interactions in the predicted complex. Strong interaction between Obg and Usfx supports the view that Obg plays an important role in stress response, essentially required for Mycobacterium survival. As concluded by various studies that Obg is crucial for Mycobacterium survival under stress, this structural information may help us in designing novel and potential inhibitors against resistant Mycobacterium strains.