Marine natural products. XXXIV. Trisindoline, a new antibiotic indole trimer, produced by a bacterium of Vibrio sp. separated from the marine sponge Hyrtios altum

A new antibiotic indole trimer named trisindoline (1) was isolated, together with a known dioxopiperazine brevianamide F (2), from the culture of a bacterium of Vibrio sp., which was separated from the Okinawan marine sponge Hyrtios altum. The structure of trisindoline (1) has been determined on the bases of physicochemical evidence and chemical synthesis.

Regional cerebral blood flow changes in human brain related to ipsilateral and contralateral complex hand movements--a PET study

The purpose of this study was to investigate the cortical motor areas activated in relation to unilateral complex hand movements of either hand, and the motor area related to motor skill learning. Regional cerebral blood flow (rCBF) was measured in eight right-handed healthy male volunteers using positron emission tomography during a two-ball-rotation task using the right hand, the same task using the left hand and two control tasks. In the two-ball-rotation tasks, subjects were required to rotate the same two iron balls either with the right or left hand. In the control task, they were required to hold two balls in each hand without movement. The primary motor area, premotor area and cerebellum were activated bilaterally with each unilateral hand movement. In contrast, the supplementary motor area proper was activated only by contralateral hand movements. In addition, we found a positive correlation between the rCBF to the premotor area and the degree of improvement in skill during motor task training. The results indicate that complex hand movements are organized bilaterally in the primary motor areas, premotor areas and cerebellum, that functional asymmetry in the motor cortices is not evident during complex finger movements, and that the premotor area may play an important role in motor skill learning.

Remodeling of the major pig xenoantigen by N-acetylglucosaminyltransferase III in transgenic pig

We have been successful in generating several lines of transgenic mice and pigs that contain the human beta-d-mannoside beta-1,4-N-acetylglucosaminyltransferase III (GnT-III) gene. The overexpression of the GnT-III gene in mice and pigs reduced their antigenicity to human natural antibodies, especially the Galalpha1-3Galbeta1-4GlcNAc-R, as evidenced by immunohistochemical analysis. Endothelial cell studies from the GnT-III transgenic pigs also revealed a significant down-regulation in antigenicity, including Hanganutziu-Deicher antigen, and dramatic reductions in both the complement- and natural killer cell-mediated pig cell lyses. Changes in the enzymatic activities of other glycosyltransferases, such as alpha1,3-galactosyltransferase, GnT-IV, and GnT-V, did not support cross-talk between GnT-III and these enzymes in the transgenic animals. In addition, we demonstrated the effect of GnT-III in down-regulating the xenoantigen of pig heart grafts, using a pig to cynomolgus monkey transplantation model, suggesting that this approach may be useful in clinical xenotransplantation in the future.

Precentral unit activity following torque pulse injections into elbow movements

(1) Precentral neural activity was studied in relation to transient load changes on self-paced elbow movements. Four Cebus monkeys were trained to turn a freely moving handle back and forth between two targets by alternating self-paced elbow flexions and extensions. Torque pulses (of 10 or 100 msec) injected randomly to load or unload the movements stretched or slackened the appropiate prime movers: biceps or triceps. Perturbed movements oscillated at about 5.5 Hz but were completed successfully in about the same time as unperturbed movements. (2) Torque pulses evoked distinct "early" responses with latencies of 20-40 msec in 134 out of 153 precenteral neurons. Oppositely directed torque pulses evoked reciprocal (i.e. increased or decreased) early responses in 61 neurons, and uniform responses in 27 neurons. (3) Early responses were followed by "late" responses with peaks succeeding one another at about 5.5 Hz in 111 neurons, but another 16 exhibited late responses only. (4) Timing of both early and late cortical responses was tightly coupled to peripheral changes. Early responses were timed by the initial torque-induced passive elbow jerk. Timing of late responses was best related to subsequent peak decelerations of accelerations. Intensity of the early but not of all late precentral responses was tightly coupled to peripheral events. (5) Torque pulses that impeded flexions or extensions evoked spinal stretch reflexes in biceps or triceps with EMG latencies of about 15 msec, leading to an acceleration peak about 25 msec later. A second EMG burst followed the first in about 30 msec. The second burst occurred about 20 msec after onset of the early precentral response, which is thought to have caused it, as well as a second acceleration peak that was seen about 60 msec after precentral response (for flexion load pulses). Peaks of late precentral responses were followed by acceleration peaks within about 70 msec. (6) An interaction akin to the spinal stretch reflex is thus revealed between elbow perturbations, early responses of precentral neurons and subsequent elbow movements: discharges of neurons that usually fire in relation to an intended movement can be altered by sudden load changes so that the neurons tend to reduce mismatch between intended and actual movements (cortical load compensation), created by the perturbation. An analagous interaction may also occur with late cortical responses.

Mode of [14C] 2-deoxy-D-glucose uptake into retrosplenial cortex and other memory-related structures of the monkey during a delayed response

Physiological studies on the monkey retrosplenial (RS) cortex have been few, and its functional role remains to be investigated. In the present study, activity of the RS cortex was investigated using radioactive 2-DG while the monkey was performing a visual tracking task with a delay (a delayed-response task) for 45 minutes. A remarkable increase in 2-DG uptake was observed equally in the left as well as in the right RS cortex. The anterior nucleus of the thalamus also showed increased 2-DG uptake. In addition, other memory-related structures (prefrontal cortex, dorsomedial nucleus of the thalamus, amygdala and hippocampus) showed a similar increase in 2-DG uptake compared to control monkeys, though their respective absolute values were different from one another. Since the RS cortex receives afferents from the anterior nucleus of the thalamus, which is one of the main nuclei of the Papez circuit, it is assumed that the RS cortex is important in memory function. Therefore, the remarkable increase in 2-DG uptake in the present study could reflect some aspects of memory or learning processes required to perform the delayed response.

Effects of dentate cooling on precentral unit activity following torque pulse injections into elbow movements

(1) The effects were studied of brief, reversible cooling of the dentate nucleus of two Cebus monkeys on the activity of 69 precentral neurons that were related to self-paced elbow flexions or extensions. Sixty-two neurons were studied when movements were randomly perturbed by transient load changes. (2) During unperturbed movements dentate cooling altered precentral activity and movement parameters in the same direction. Extension movements and extension-related precentral neurons developed oscillations and rhythmical activity at about 4 Hz with increased peak values of acceleration and discharge intensity. Flexion peak accelerations and dynamic properties of flexion-related precentral neurons decreased. (3) Dentate cooling had no major effects on the "early" precentral responses to torque pulses and on the initial rapid movement adjustment. (4) Dentate cooling decreased intensity of "late" precentral responses and slowed their frequency together with associated movement oscillations from 5-6 Hz to 3-4 Hz. EMG bursts of biceps and triceps were prolonged accordingly. (5) It is concluded that the tightly coupled interaction between precentral motor cortex and the evolving movement was independent of dentate function in the early stage of the cortical load compensation. The dentate nucleus was involved, however, in adjusting intensity and frequency of subsequent late precentral responses and of movement oscillations.

Effects of stimulation of corpus callosum on precentral neuron activity in the awake monkey

The effects of stimulation of the corpus callosum (CC) on precentral neurons were studied in monkeys performing motor tasks with either forelimb. Of a total of 246 precentral neurons that were tested with CC stimulation, 70 were orthodromically and 12 were antidromically activated. The percentages of neurons orthodromically activated by CC stimulation were the same in pyramidal tract neurons (PTNs) (31%) and non-PTNs (31%). The mean latency of neuronal activation by CC stimulation was similar in PTNs and non-PTNs. Precentral neurons were divided into two groups with respect to muscular contractions evoked by intracortical stimulation: neurons related to finger, wrist, and elbow movements (distal group) and those related to shoulder or axial movements (proximal group). The percentages of neurons orthodromically activated by CC stimulation were similar in both groups; 25% in distal and 29% in proximal groups. However, the mean latency of orthodromic CC activation was significantly shorter for the proximal than for the distal group. Precentral neurons were classified into three groups; neurons related to finger and/or wrist movement tasks (F-W group), those related to arm movement tasks in addition to finger and/or wrist tasks (F, W + A group), and those related to arm movements only (A group). The percentages of neurons orthodromically activated by CC stimulation were similar in the three groups. The mean latencies of neuronal activities were a little longer in the F-W group than in the A group or the F, W + A group. Precentral neurons were classified into three groups in relation to ipsilateral or contralateral forelimb movements: neurons related to ipsilateral movements (ipsi neurons, n = 13), those related to ipsilateral as well as contralateral movements (bilat neurons, n = 50) and those related to contralateral movements (contra neurons, n = 136). The percentages of neurons orthodromically activated by CC stimulation were 15 (2/13, ipsi neurons), 24.0 (12/50, bilat neurons), and 25.0% (34/136, contra neurons), respectively. The mean latencies of neuronal activation were compared between two groups; one group was composed of ipsi and bilat neurons, and the other group was of contra neurons. The mean latency was a little shorter for the ipsi + bilat group than for the contra group.(ABSTRACT TRUNCATED AT 400 WORDS)

Deep inner-shell multiphoton ionization by intense x-ray free-electron laser pulses

We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xe(n+) with n up to 26 is produced at a photon energy of 5.5 keV. The observed high charge states (n≥24) are produced via five-photon absorption, evidencing the occurrence of multiphoton absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement with the experiment, elucidates the complex pathways of sequential electronic decay cascades accessible in heavy atoms. The present study of heavy-atom ionization dynamics in high-intensity hard-x-ray pulses makes a step forward towards molecular structure determination with x-ray free-electron lasers.

Characteristics of the ipsilateral movement-related neuron in the motor cortex of the monkey

The characteristics of the precentral neuron activity related to ipsilateral movements were studied while the monkey was performing finger, wrist and arm movements on either side. Out of 197 task-related neurons, 134 discharged in association with contralateral movements, but not with any one of 3 ipsilateral movements. Fifty neurons discharged with bilateral movements. Thirteen neurons discharged in association with ipsilateral movements (ipsi-neurons). Ten were recorded from the trunk or shoulder area of the motor cortex and were accompanied by contraction of those muscles by intracortical stimulation (ICS). The remaining 3 were related to elbow or wrist, but no ipsi-neurons were related to finger muscle contractions. In ipsilateral task performance, 7 ipsi-neurons discharged in association with finger and/or wrist movements in addition to arm movement. Five others were associated with arm movement. The last one discharged with wrist movement. Most of the units showed similar response to contralateral movement. Ipsi-neurons were classified into two groups. One group was recorded around the sulcus precentralis superior, had the lower threshold current and was mostly associated with finger, wrist and arm movements. The other was recorded in the rostral motor cortex, and had the higher threshold current and was related to arm movement. Among 185 neurons to which pyramidal tract stimulation was delivered, 2 out of the 80 PTNs and 11 out of the 105 non-PTNs were ipsi-neurons. EMGs were recorded from various muscles involved in the forelimb movements. Arm and finger muscles showed no activity when the monkey used the ipsilateral hand, while most of the shoulder and trunk muscles showed tonic or moderate transient changes in the activity during the ipsilateral tasks. The ipsi-neuron activity was discussed in consideration with EMGs.

Infantile Cases of Sitosterolaemia with Novel Mutations in the ABCG5 Gene: Extreme Hypercholesterolaemia is Exacerbated by Breastfeeding

Few data exists regarding the clinical impact of breastfeeding in infantile sitosterolaemic cases. We report four Japanese infantile cases of sitosterolaemia, an extremely rare inherited disease characterised by increased serum levels of plant sitosterol, presenting with severe hypercholesterolaemia and systemic xanthomas exacerbated by breastfeeding. In these four cases, genetic analyses were performed for low-density lipoprotein (LDL) receptor, proprotein convertase subtilisin/kexin type 9 (PCSK9), LDL receptor adaptor protein 1 and ATP-binding cassette (ABC) subfamily G member 5 and 8 (ABCG5 and ABCG8) genes. We assessed their clinical manifestations, including responsiveness to a variety of treatments, especially to weaning from breastfeeding and use of ezetimibe. Two pairs of mutations in the ABCG5 gene in each case, including two novel mutations (c.130C>T or p.Ser44Ala and c.1813_1817delCTTTT or p.Pro558GlufsX14) and two known mutations (c.1306G>A or p.Arg389His and c.1336C>T or p.Arg446X), were identified. Significant reductions in cholesterol levels were obtained by means of weaning from breastfeeding alone. Substantial reductions in sitosterol levels, without any apparent side effects, were observed with ezetimibe. In conclusion, we have identified infantile Japanese sitosterolaemic subjects with extreme hypercholesterolaemia exacerbated by breastfeeding. Their unique response to weaning from breastfeeding, as well as to use of ezetimibe, could provide insights into the metabolic basis of sterols in humans.

The possible use of HLA-G1 and G3 in the inhibition of NK cell-mediated swine endothelial cell lysis

The splicing isoform of HLA-G that is expressed in xenogeneic cells, and its effect on NK-mediated direct cytotoxicity was examined, using stable Chinese hamster ovary (CHO) cell or swine endothelial cell (SEC) transfectants. cDNAs of HLA-G (G1 and G3) and human beta2-microglobulin were prepared and subcloned into the expression vector, pCXN. The transfected HLA-G1 was easily expressed on SEC, and co-transfection with human beta2-microglobulin led to an enhanced level of HLA-G1 expression, as evidenced by flow cytometry. The expressed HLA-G1 significantly suppressed NK-mediated SEC cell lysis, which is an in vitro delayed-type rejection model of a xenograft. On the other hand, the swine leucocyte antigen (SLA) class I molecules could be up-regulated as the result of the transfection of human beta2-microglobulin, but did not down-regulate human NK-mediated SEC lysis. The HLA-G3 was not expressed on CHO and SEC in contrast to HLA-G1, as the result of the transfection. The gene introduction of HLA-G3 in SEC showed no protective effect from human NK cells. However, indirect evidence demonstrated that HLA-G3 transfection resulted in HLA-E expression, but not itself, when transfected to the human cell line, 721.221, thus providing some insight into its natural function in human cells. The present findings suggest that the expression of HLA-G1 on the cell surface could serve as a new approach to overcoming NK-mediated immunity to xenografts.

Synthesis of a new Cre recombinase gene based on optimal codon usage for mammalian systems

The origin of the Cre recombinase gene is bacteriophage P1, and thus the codon usages are different from in mammals. In order to adapt this codon usage for mammals, we synthesized a "mammalian Cre recombinase gene" and examined its expression in Chinese hamster ovarian tumor (CHO) cells. Significant increases in protein production as well as mRNA levels were observed. When the recombination efficiency was compared using CHO cell transfectants having a cDNA containing loxP sites, the "mammalian Cre recombinase gene" recombined the loxP sites much more efficiently than the wild-type Cre recombinase gene.

Interatomic Coulombic decay cascades in multiply excited neon clusters

In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation.

Interatomic Coulombic decay (ICD) is a relaxation of an atom in a weakly bound environment by the transfer of excess energy to ionize the neighbouring atom. Here the authors observe intra-Rydberg ICD in neon clusters, which is a decay that involves the ionization of Rydberg atoms in the cluster.