FTY720 requires vitamin B12-TCN2-CD320 signaling in astrocytes to reduce disease in an animal model of multiple sclerosis

Vitamin B12 (B12) deficiency causes neurological manifestations resembling multiple sclerosis (MS); however, a molecular explanation for the similarity is unknown. FTY720 (fingolimod) is a sphingosine 1-phosphate (S1P) receptor modulator and sphingosine analog approved for MS therapy that can functionally antagonize S1P1. Here, we report that FTY720 suppresses neuroinflammation by functionally and physically regulating the B12 pathways. Genetic and pharmacological S1P1 inhibition upregulates a transcobalamin 2 (TCN2)-B12 receptor, CD320, in immediate-early astrocytes (ieAstrocytes; a c-Fos-activated astrocyte subset that tracks with experimental autoimmune encephalomyelitis [EAE] severity). CD320 is also reduced in MS plaques. Deficiency of CD320 or dietary B12 restriction worsens EAE and eliminates FTY720's efficacy while concomitantly downregulating type I interferon signaling. TCN2 functions as a chaperone for FTY720 and sphingosine, whose complex induces astrocytic CD320 internalization, suggesting a delivery mechanism of FTY720/sphingosine via the TCN2-CD320 pathway. Taken together, the B12-TCN2-CD320 pathway is essential for the mechanism of action of FTY720.

A microfluidic platform for highly parallel bite by bite profiling of mosquito-borne pathogen transmission

Mosquito bites transmit a number of pathogens via salivary droplets deposited during blood-feeding, resulting in potentially fatal diseases. Little is known about the genomic content of these nanodroplets, including the transmission dynamics of live pathogens. Here we introduce Vectorchip, a low-cost, scalable microfluidic platform enabling high-throughput molecular interrogation of individual mosquito bites. We introduce an ultra-thin PDMS membrane which acts as a biting interface to arrays of micro-wells. Freely-behaving mosquitoes deposit saliva droplets by biting into these micro-wells. By modulating membrane thickness, we observe species-dependent differences in mosquito biting capacity, utilizable for selective sample collection. We demonstrate RT-PCR and focus-forming assays on-chip to detect mosquito DNA, Zika virus RNA, as well as quantify infectious Mayaro virus particles transmitted from single mosquito bites. The Vectorchip presents a promising approach for single-bite-resolution laboratory and field characterization of vector-pathogen communities, and could serve as a powerful early warning sentinel for mosquito-borne diseases.

Characterization of Md5-BAC-REV-LTR virus as Marek's disease vaccine in commercial meat-type chickens: protection and immunosuppression

Md5-BAC-REV-LTR is a recombinant Marek's disease virus (MDV), with an insertion of the long terminal repeat (LTR) of reticuloendotheliosis virus (REV) into the genome of the highly virulent MDV strain rMd5. It has been shown that Md5-BAC-REV-LTR does not induce tumours and confers high protection against challenge with MDV in 15 × 7 chickens. The objective of the present study was to evaluate the protection and safety (in terms of oncogenicity and immunosuppression) of Md5-BAC-REV-LTR in commercial meat-type chickens bearing maternal antibodies against MDV. Our results show that sub-cutaneous administration of Md5-BAC-REV-LTR at 1 day of age conferred high protection (protection index PI = 84.2) against an early challenge (1 day) by contact exposure to shedder birds infected with the vv+ MDV 648A strain. In such stringent challenge conditions, Md5-BAC-REV-LTR was more protective than a commercial CVI988 (PI = 12.4) and similar to the experimental vaccine Md5-BACΔmeq (PI = 92.4). Furthermore, Md5-BAC-REV-LTR did not induce either tumours or immunosuppression in this study. Immunosuppression was evaluated by the relative lymphoid organ weights and also by the ability of the vaccine to induce late-MDV-induced immunosuppression associated with reactivation of the virus. This study shows that Md5-BAC-REV-LTR has the potential to be used as a MD vaccine and is highly protective against early challenge with vv+ MDV. RESEARCH HIGHLIGHTSMd5-BAC-REV-LTR is highly protective against early challenge with vv+ MDV in commercial meat-type chickens.Md5-BAC-REV-LTR does not cause early immunosuppression.Md5-BAC-REV-LTR does not cause late immunosuppression.Unlike other serotype 1 vaccines, Md5-BAC-REV-LTR is not detected in feather pulp at 7 days post vaccination.

The practice of polypharmacy involving herbal and prescription medicines in the treatment of diabetes mellitus, hypertension and gastrointestinal disorders in Jamaica

The interference in the metabolism of a drug by another drug, food or other foreign chemical is commonly observed and often leads to clinically significant adverse drug reactions. In Jamaica, there is an extensive use of natural products as medicines, although there is little information on whether natural medicines are used along with prescription medicines, which might increase the likelihood of drug adversities. This current pilot survey was initiated to gain information on the prevalence of such polypharmacy practices. Two concurrent surveys were carried out in Kingston (an urban parish) and Clarendon (a rural parish) in 743 patients above age 14 years with diabetes mellitus, hypertension and gastrointestinal disorders of persons who visited health centres and pharmacies. Patrons visiting these places at various times of the day were informed of the nature of the questionnaire and willing participants with the above disease conditions and who were on prescription medicines were included in the survey. The results indicated that 80% of the respondents reported combining natural products in their treatment along with prescription medicines, with only 13% of those patients informing their physicians of such practices. Such polypharmacy practices were independent of the type of disease among both males and females and was statistically most prevalent (p < 0.001) in the 47-57-year age group. There was a significant association (p < 0.001) between such treatment practices and place of residence with 92% of the rural community engaging in polypharmacy but 70% of the urban did likewise. Therefore, being aware of the prevalence of multiple therapy practices would be especially useful when designing a pharmaco-vigilance system.

A computational fluid dynamic study of hawkmoth hovering

A computational fluid dynamic (CFD) modelling approach is used to study the unsteady aerodynamics of the flapping wing of a hovering hawkmoth. We use the geometry of a Manduca sexta-based robotic wing to define the shape of a three-dimensional 'virtual' wing model and 'hover' this wing, mimicking accurately the three-dimensional movements of the wing of a hovering hawkmoth. Our CFD analysis has established an overall understanding of the viscous and unsteady flow around the flapping wing and of the time course of instantaneous force production, which reveals that hovering flight is dominated by the unsteady aerodynamics of both the instantaneous dynamics and also the past history of the wing. &lt;P&gt; A coherent leading-edge vortex with axial flow was detected during translational motions of both the up- and downstrokes. The attached leading-edge vortex causes a negative pressure region and, hence, is responsible for enhancing lift production. The axial flow, which is derived from the spanwise pressure gradient, stabilises the vortex and gives it a characteristic spiral conical shape. &lt;P&gt; The leading-edge vortex created during previous translational motion remains attached during the rotational motions of pronation and supination. This vortex, however, is substantially deformed due to coupling between the translational and rotational motions, develops into a complex structure, and is eventually shed before the subsequent translational motion. &lt;P&gt; Estimation of the forces during one complete flapping cycle shows that lift is produced mainly during the downstroke and the latter half of the upstroke, with little force generated during pronation and supination. The stroke plane angle that satisfies the horizontal force balance of hovering is 23.6 degrees , which shows excellent agreement with observed angles of approximately 20-25 degrees . The time-averaged vertical force is 40 % greater than that needed to support the weight of the hawkmoth.

Measuring the angle of attack of beating insect wings: robust three-dimensional reconstruction from two-dimensional images

A robust technique for determining the angle of attack of insect wings from film of free flight has to date proved elusive. This report describes the development of two new methods &shy; the Strips and Planes techniques &shy; which were designed to overcome some of the limitations experienced in previous studies. The accuracy and robustness of these novel methods were tested extensively using simulated hawkmoth wing outlines generated for a realistic range of wing positions and torsion. The results were compared with those from two existing methods &shy; the Symmetry and Landmarks procedures. The performance of the latter technique will be strongly species-dependent; it could not be successfully applied to hawkmoth flight because of practical difficulties in obtaining suitable landmarks. The Planes method was the least successful of the remaining techniques, especially during those phases of the wingbeat when the orientations of the two wings relative to the camera viewpoint were similar. The Symmetry and Strips methods were tested further to investigate the effects on their performance of introducing additional camber or wing motion asymmetry. The results showed clearly that the Strips method should be the technique of choice wherever the axis of wing torsion is close to the longitudinal axis of the wing. The procedure involves the experimenter matching a model wing divided into chordwise strips to the true wing outline digitized from high-speed film. The use of strips rather than the points digitized in previous studies meant that the analysis required only one wing outline to be digitized. Symmetry of motion between the left and right wings is not assumed. The implications of requiring human input to the Strips method, as opposed to the strictly numerical algorithms of the alternative techniques, are discussed. It is argued that the added flexibility that this provides in dealing with images which have typically been recorded in suboptimal conditions outweighs the introduction of an element of subjectivity. Additional observations arising from the use of the Strips analysis with high-speed video sequences of hawkmoth flight are given.

Power output from a flight muscle of the bumblebee Bombus terrestris. I. Some features of the dorso-ventral flight muscle

1. Isometric contractions from the asynchronous dorso-ventral flight muscle of the bumblebee Bombus terrestris were slow and rather weak. The twitch duration (onset to 50 % relaxation) was approximately 300 ms at 30 &deg;C and 170 ms at 40 &deg;C. The maximum tetanic tension was approximately 40 kN m-2; the ratio of twitch force to tetanic force was approximately 0.2. 2. The unstimulated muscle was quite resistant to stretch, with a low-frequency stiffness of 730 kN m-2 at muscle lengths close to that of the muscle in vivo. The length&shy;tension curve for active tetanic tension (that is the increase in tension above the passive level during stimulation) was very narrow, with a half-width equal to only 17 % of the optimal length. 3. The muscle strain during tethered flight was approximately 2 % peak-to-peak, occasionally reaching 3 %. Strain amplitude increased with wing stroke frequency. The thoracic vibration frequency of escape buzzing, during which the wings are not extended but are folded over the abdomen, was approximately twice that of tethered flight but the muscle strain was similar to that of flight.

Validation of the doubly labelled water technique for bumblebees Bombus terrestris (L.)

The doubly labelled water (DLW) technique was validated for the bumblebee Bombus terrestris (L.) using respirometry (RESP) from tethered roundabout flights. We injected small volumes (1 &micro;l) of a mixture containing low concentrations of deuterium and 18O and withdrew 1-2 &micro;l of haemolymph to determine initial 18O concentration. The injected isotopes were equilibrated with the body water pool after 10 min, and high material turnover allowed the analysis of final blood isotope concentrations after 5-7 h. On average (n=16), values measured using the DLW technique exceeded values measured using RESP by 3.1&plusmn;9.9 %, a difference that was not statistically significant at the 99 % confidence level. The absolute error was 7.4&plusmn;7.1 % (mean &plusmn; s.d.). Isotope dilution spaces of both deuterium and 18O were almost identical with the body water pool. We corrected for isotope fractionation, using a slightly higher value than usual for one of the fractionation factors. The single most important variable to influence DLW results, which could not be measured with the desired accuracy, was the volume of the final body water pool N. An overestimate of final N possibly resulted in the DLW overestimate.

Inferences concerning crossbridges from work on insect muscle

This paper presents a number of separate results concerning crossbridge attachment: [1] X-ray diffraction from live bumble bee flight muscle shows a set of layer lines distinct from that of relaxed Lethocerus, in which the apparent myosin helix is shorter than that of the actin. [2] Rigor crossbridges of Lethocerus are not rotatable by stretch. [3] Rabbit and Lethocerus fibres in rigor relaxed by ATP at -35 degrees C show evidence of non-rigor crossbridge attachment.