bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic resonance imaging compared with electrodiagnostic studies in patients with suspected carpal tunnel syndrome: predicting symptoms, function, and surgical benefit at 1 year
Authors: Jarvik Jeffrey G. , Comstock Bryan A. , Heagerty Patrick J. , Haynor David R. , Fulton-Kehoe Deborah , Kliot Michel , Franklin Gary M.
Published: February 2008

Object

The goal in this study of patients with clinical carpal tunnel syndrome (CTS) was to compare the usefulness of magnetic resonance (MR) imaging with that of electrodiagnostic studies (EDSs) for the following purposes: 1) prediction of 1-year outcomes and 2) identification of patients who are likely to benefit from surgical treatment.

Methods

The authors prospectively enrolled 120 patients with clinically suspected CTS. The participants were tested using standardized EDSs, MR imaging, and a battery of questionnaires, including the Carpal Tunnel Syndrome Assessment Questionnaire, a well-validated 5-point score of symptoms and function. The EDSs and MR images were each interpreted independently. Patients were reevaluated after 1 year. The decision to treat patients conservatively or by carpal tunnel release was made by the individual surgeon, who had access to the initial EDS but not MR imaging results. Univariate and multivariate analyses were used to determine associations between 1-year outcomes and baseline diagnostic tests.

Results

The authors recontacted 105 of 120 participants at 12 months. Of these, 30 patients had had surgery and 75 had not. Patients who had undergone surgery showed greater improvement at 1 year than those who had not had surgery. The length of the abnormal T2-weighted nerve signal on MR imaging and median–ulnar sensory latency difference were the strongest predictors of surgical benefit. There was a clear patient preference for the MR imaging over EDSs.

Conclusions

The findings obtained with MR imaging of the carpal tunnel predict surgical benefit independently of nerve conduction studies.
Inhibitory effect of gap junction blockers on cerebral vasospasm
Authors: Hong Tao , Wang Yang , Wang Hai-tao , Wang Huan
Published: February 2008

Object

The gap junction is important in the propagation of dilation/constriction signals along vessels for coordinated behavior in control of vascular tone. The authors hypothesized that gap junctions might play a role in cerebral vasospasm following subarachnoid hemorrhage (SAH). The aims of the present study were to investigate the role of gap junctions and to observe the potential therapeutic efficacy of gap junction blockers in cerebral vasospasm in vitro and in vivo.

Methods

For the in vitro investigation, the effect of heptanol on the oxyhemoglobin (HbO2)-induced contraction of isolated rabbit basilar arteries (BAs) was observed by using an isometric tension-recording method. For the in vivo experiments, the potential therapeutic efficacy of heptanol and carbenoxolone was surveyed after it was given intravenously in the rabbit double-hemorrhage model. Light microscopy was performed to assess the morphological changes in the arteries examined.

Results

For the in vitro method, heptanol significantly inhibited the sustained contraction induced both by HbO2 and K+ in the BA rings. The magnitude of the heptanol-induced relaxation was dose dependent. The inhibitory effect of heptanol on the K+-induced vasoconstriction was weaker than that on the HbO2-induced constriction. After arterial rings were pretreated for 10 minutes, heptanol significantly decreased their responses to the HbO2-induced contraction. For the in vivo method, heptanol and carbenoxolone significantly decreased the narrowing of BAs when given intravenously in the rabbit double-hemorrhage model. In both treated groups, the diameters of the arteries had not changed significantly on Day 7 compared with those of the arteries in the SAH + vehicle and the SAH-only group.

Conclusions

Heptanol and carbenoxolone significantly inhibited the experimental cerebral vasospasm both in vitro and in vivo. Blockage of gap junctions is a probable candidate for a new approach in the treatment of cerebral vasospasm. Gap junctions may play a pathophysiological role in cerebral vasospasm.
Association between semicarbazide-sensitive amine oxidase, a regulator of the glucose transporter, and elastic lamellae thinning during experimental cerebral aneurysm development
Authors: Sibon Igor , Mercier Nathalie , Darret Danièle , Lacolley Patrick , Lamazière Jean-Marie Daniel
Published: February 2008

Object

Amine oxidases play a key role in the polymerization and cross-linking of the collagens and elastic lamellae of the arterial wall. The loss of elastic lamellae integrity is one of the first steps in the genesis of a cerebral aneurysm. The authors investigated the relation between semicarbazide-sensitive amine oxidase (SSAO) and the organization of the cerebral arterial wall during aneurysm development.

Methods

Intracranial aneurysms were induced in rats via unilateral carotid artery ligation and renovascular hypertension. This modified Hashimoto model was used to create elevated blood pressure associated with shear stress in cerebral arteries. The authors immunohistologically investigated some markers of the extracellular matrix (Types I, III, and IV collagen and elastin), vascular smooth muscle cell differentiation (smooth muscle myosin heavy chain [sm-MHC], α–smooth muscle actin, and desmin), and amine oxidases (SSAO and lysyl oxidase [LOX]) in the cerebral arterial wall in control and treated rats 1, 2, 3, 4, and 6 months after the surgical procedure.

Results

The authors found severe disorganization and thinning of the elastic lamellae and a dramatic reduction in SSAO activity and immunostaining during cerebral aneurysm development. In contrast, LOX markers were slightly increased. Elastic lamellae thinning was highly correlated with decreases in SSAO (r = 0.76, p < 0.0001). There was also a correlation between sm-MHC and SSAO levels.

Conclusions

The data suggested that cerebral hemodynamic modifications induce decreases in SSAO activity resulting in cell dedifferentiation and inducing dysregulation of glucose transport.
A prospective gait analysis study in patients with diplegic cerebral palsy 20 years after selective dorsal rhizotomy
Authors: Langerak Nelleke G. , Lamberts Robert P. , Fieggen A. Graham , Peter Jonathan C. , van der Merwe Lize , Peacock Warwick J. , Vaughan Christopher L.
Published: February 2008

Object

Selective dorsal rhizotomy (SDR) has been widely performed for the reduction of spasticity in patients with cerebral palsy during the past 2 decades. The objective of this study was to determine whether the surgery has yielded long-term functional benefits for these patients.

Methods

The authors present results from a prospective 20-year follow-up study of locomotor function in 13 patients who underwent an SDR in 1985. For comparison, we also present gait data for 48 age-matched healthy controls (12 at each of 4 time points). Patients were studied preoperatively and then at 1, 3, 10, and 20 years after surgery. Study participants were recorded in the sagittal plane while walking using a digital video camera, and 6 standard gait parameters were measured.

Results

In this group of patients 20 years after surgery, knee range of motion (ROM) was on average 12° greater than preoperative values (p < 0.001). Hip ROM before surgery was no different from that in the healthy control group. This parameter increased markedly immediately after surgery (p < 0.001) but had returned to normal after 20 years. The knee and hip midrange values—a measure of the degree of “collapse” due to muscle weakness after surgery—had returned to preoperative levels after 20 years, although they were respectively 11 and 8° greater than those in healthy controls. Both temporal-distance parameters (dimensionless cadence and dimensionless step length) were significantly greater at 20 years than preoperative values (cadence, p = 0.003; step length, p = 0.02), leading to improved walking speed.

Conclusions

Twenty years after undergoing SDR, our patients showed improved locomotor function compared with their preoperative status.
Surgical treatment of moyamoya syndrome in patients with sickle cell anemia: outcome following encephaloduroarteriosynangiosis
Authors: Hankinson Todd C. , Bohman Leif-Erik , Heyer Geoffrey , Licursi Maureen , Ghatan Saadi , Feldstein Neil A. , Anderson Richard C. E.
Published: February 2008

Object

Children with sickle cell anemia (SCA) and moyamoya syndrome carry a significant risk of ischemic stroke. Given the success of encephaloduroarteriosynangiosis (EDAS) or pial synangiosis in the treatment of moyamoya disease, the purpose of this study was to examine whether it reliably and durably protected children with SCA and moyamoya syndrome against cerebrovascular complications.

Methods

The authors retrospectively reviewed a series of 12 patients with SCA who developed clinical and/or radiological evidence of moyamoya syndrome and underwent EDAS.

Results

Eleven patients (92%) presented following a cerebrovascular accident (CVA), transient ischemic attack (TIA), or seizure. Magnetic resonance (MR) imaging or angiography suggested moyamoya vascular changes, and cerebral angiography confirmed the diagnosis in all 12 patients. At the time of surgery, the median age was 12.3 years (range 6.8–19.4 years). Ten (83%) of 12 patients had a history of CVA, and 4 of these patients were compliant with a transfusion protocol at the time of their CVA. Bilateral (7 patients) or unilateral (5 patients) EDAS was performed without complications. The mean follow-up period was 46.8 months (range 8.1–106 months). During the follow-up period, 2 patients (16.7%) suffered cerebrovascular events. One patient, who was stroke-free preoperatively, suffered a CVA 3 weeks after the procedure. The other patient suffered a single left lower-extremity TIA 18 months following right-sided EDAS. She returned to her neurological baseline condition and remains stable 53 months postoperatively. Seven patients underwent follow-up angiography or MR angiography, and evidence of revascularization was noted in all cases. At this time, no patient has developed progressive disease requiring a contralateral procedure after unilateral EDAS.

Conclusions

The EDAS procedure is a safe and effective treatment option in patients with SCA who develop moyamoya syndrome.
Identification of distinct and overlapping cortical areas for bilingual naming and reading using cortical stimulation
Authors: Serafini Sandra , Gururangan Sridharan , Friedman Allan , Haglund Michael
Published: February 2008

✓A bilingual pediatric patient who underwent tumor resection was mapped extraoperatively using cortical stimulation to preserve English and Hebrew languages. The authors mapped both languages by using 4 tasks: 1) English visual naming, 2) Hebrew visual naming, 3) read English/respond Hebrew, and 4) Hebrew reading. Essential cortical sites for primary and secondary languages were compared, photographically recorded, and plotted onto a schematic brain of the patient. Three types of sites were found in this patient: 1) multiuse sites (multiple tasks, both languages) in frontal, temporal, and parietal areas; 2) single-task sites (1 task, both languages) in postcentral and parietal areas; and 3) single-use sites (1 task, 1 language) in frontal, temporal, and parietal areas. These results lend support to the concept that bilingual patients can have distinct cortical representations of each language and of different language tasks, in addition to overlapping or shared sites that support both languages and multiple tasks.
Complete cranium bifidum without scalp abnormality
Authors: Çelik Suat E. , Kara Ayhan
Published: February 2008

✓Cranium bifidum is an unusual lesion in newborns. The majority of previously reported cases have described enlarged parietal foramina with some scalp and other congenital abnormalities. In this report the authors present the first case of complete cranium bifidum without any other anomaly. The cranial defect persisted for 3 years during the follow-up period. No hereditary or familial transition has been observed. The authors conclude that such an extremely rare occurrence of complete cranium bifidum may be a result of a coincidental mutation.
Nerve repair using acidic fibroblast growth factor in human cervical spinal cord injury: a preliminary Phase I clinical study
Authors: Wu Jau-Ching , Huang Wen-Cheng , Tsai Yun-An , Chen Yu-Chun , Cheng Henrich
Published: February 2008

Object

The aim of this study was to assess functional outcomes of nerve repair using acidic fibroblast growth factor (FGF) in patients with cervical spinal cord injury (SCI).

Methods

Nine patients who had cervical SCI for longer than 5 months were included in pre- and postoperative assessments of their neurological function. The assessments included evaluating activities of daily living, associated functional ability, and degree of spasticity, motor power, sensation, and pain perception. After the first set of assessments, the authors repaired the injured segment of the spinal cord using a total laminectomy followed by the application of fibrin glue containing acidic FGF. Clinical evaluations were conducted 1, 2, 3, 4, 5, and 6 months after the surgery. Preoperative versus postoperative differences in injury severity and grading of key muscle power and sensory points were calculated using the Wilcoxon signed-rank test.

Results

The preoperative degree of injury severity, as measured using the American Spinal Injury Association (ASIA) scoring system, showed that preoperative motor (52.4 ± 25.9 vs 68.6 ± 21.5), pinprick (61.0 ± 34.9 vs 71.6 ± 31.0), and light touch scores (57.3 ± 33.9 vs 71.9 ± 30.2) were significantly lower than the respective postoperative scores measured 6 months after surgery (p = 0.005, 0.012, and 0.008, respectively).

Conclusions

Based on the significant difference in ASIA motor and sensory scale scores between the preoperative status and the 6-month postoperative follow-up, this novel nerve repair strategy of using acidic FGF may have a role in the repair of human cervical SCI. Modest nerve regeneration occurred in all 9 patients after this procedure without any observed adverse effects. This repair strategy thus deserves further investigation, clinical consideration, and refinement.
Predictive value of intraoperative neurophysiological monitoring during cervical spine surgery: a prospective analysis of 1055 consecutive patients
Authors: Kelleher Michael O. , Tan Gamaliel , Sarjeant Roger , Fehlings Michael G.
Published: February 2008

Object

Despite the growing use of multimodal intraoperative monitoring (IOM) in cervical spinal surgery, limited data exist regarding the sensitivity, specificity, and predictive values of such a technique in detecting new neurological deficits in this setting. The authors sought to define the incidence of significant intraoperative electrophysiological changes and new postoperative neurological deficits in a cohort of patients undergoing cervical surgery.

Methods

The authors conducted a prospective analysis of a consecutive series of patients who had undergone cervical surgery during a 5-year period at a university-based neurosurgical unit, in which multimodal IOM was recorded. Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) were determined using standard Bayesian techniques. The study population included 1055 patients (614 male and 441 female) with a mean age of 55 years.

Results

The IOM modalities performed included somatosensory evoked potential (SSEP) recording in 1055 patients, motor evoked potential (MEP) recording in 26, and electromyography (EMG) in 427. Twenty-six patients (2.5%) had significant SSEP changes. Electromyographic activity was transient in 212 patients (49.6%), and 115 patients (26.9%) had sustained burst or train activity. New postoperative neurological deficits occurred in 34 patients (3.2%): 6 had combined sensory and motor deficits, 7 had new sensory deficits, 9 had increased motor weakness, and 12 had new root deficits. Of these 34 patients, 12 had spinal tumors, of which 7 were intramedullary. Overall, of the 34 new postoperative deficits, 21 completely resolved, 9 partially resolved, and 4 had no improvement. The deficits that completely resolved did so on average 3.3 months after surgery. Patients with deficits that did not fully resolve (partial or no improvement) were followed up for an average of 1.8 years after surgery.

Somatosensory evoked potentials had a sensitivity of 52%, a specificity of 100%, a PPV of 100%, and an NPV of 97%. Motor evoked potential sensitivity was 100%, specificity 96%, PPV 96%, and NPV 100%. Electromyography had a sensitivity of 46%, specificity of 73%, PPV of 3%, and an NPV of 97%.

Conclusions

Combined neurophysiological IOM with EMG and SSEP recording and the selective use of MEPs is helpful for predicting and possibly preventing neurological injury during cervical spine surgery.
Evaluation of lumbar segmental instability in degenerative diseases by using a new intraoperative measurement system
Authors: Hasegawa Kazuhiro , Kitahara Ko , Hara Toshiaki , Takano Ko , Shimoda Haruka , Homma Takao
Published: February 2008

Object

In vivo quantitative measurement of lumbar segmental stability has not been established. The authors developed a new measurement system to determine intraoperative lumbar stability. The objective of this study was to clarify the biomechanical properties of degenerative lumbar segments by using the new method.

Methods

Twenty-two patients with a degenerative symptomatic segment were studied and their measurements compared with those obtained in normal or asymptomatic degenerative segments (Normal group). The measurement system produces cyclic flexion–extension through spinous process holders by using a computer-controlled motion generator with all ligamentous structures intact. The following biomechanical parameters were determined: stiffness, absorption energy (AE), and neutral zone (NZ). Discs with degeneration were divided into 2 groups based on magnetic resonance imaging grading: degeneration without collapse (Collapse[−]) and degeneration with collapse (Collapse[+]). Biomechanical parameters were compared among the groups. Relationships among the biomechanical parameters and age, diagnosis, or radiographic parameters were analyzed.

Results

The mean stiffness value in the Normal group was significantly greater than that in Collapse(−) or Collapse(+) group. There was no significant difference in the average AE value among the Normal, Collapse(−), and Collapse(+) groups. The NZ in the Collapse(−) was significantly higher than in the Normal or Collapse(+) groups. Stiffness was negatively and NZ was positively correlated with age. Stiffness demonstrated a significant negative and NZ a significant positive relationship with disc height, however.

Conclusions

There were no significant differences in stiffness between spines in the Collapse(−) and Collapse(+) groups. The values of a more sensitive parameter, NZ, were higher in Collapse(−) than in Collapse(+) groups, demonstrating that degenerative segments with preserved disc height have a latent instability compared to segments with collapsed discs.
Destructive pathological changes in the rat spinal cord due to chronic mechanical compression
Authors: Xu Peng , Gong Wei-Ming , Li Yao , Zhang Tao , Zhang Kai , Yin De-Zhen , Jia Tang-Hong
Published: February 2008

Object

Chronic mechanical compression of the spinal cord, which is commonly caused by degeneration of the spine, impairs motor and sensory functions insidiously and progressively. Yet the exact mechanisms of chronic spinal cord compression (SCC) remain to be elucidated. To study the pathophysiology of this condition, the authors developed a simple animal experimental model that reproduced the clinical course of mechanical compression of the spinal cord.

Methods

A custom-designed compression device was implanted on the exposed spinal cord of female Wistar rats between the T-7 and T-9 vertebrae. A root canal screw attached to a plastic plate was tightened 1 complete turn (1 pitch) every 7 days for 6 weeks. The placement of the compression device and the degree of compression were validated every week using radiography. Furthermore, a motor sensory deficit index was also calculated every week. After 3, 6, 9, or 12 weeks, the compressed T7–9 spinal cords were harvested and examined histologically.

Results

Lateral projection of the thoracic spine showed a progressively increasing rate of mean spinal cord narrowing in the compression group. Motor and sensory deficiencies were observed from Week 3 onward; paralysis was observed in 2 rats at Week 12. Motor deficiency appeared earlier than sensory deficiency. Obvious pathological changes were observed starting at Week 6. The number of neurons in the gray matter of rats with chronic compression of the spinal cord decreased progressively in the 6- and 9-week compression groups. In the white matter, myelin destruction and loss of axons and glia were noted. The number of terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling (TUNEL)–positive neurons increased in the ventral-to-dorsal direction. The number of TUNEL-positive cells increased from Week 6 onward and peaked at Week 9.

Conclusions

This practical model accurately reproduces characteristic features of clinical chronic SCC, including progressive motor and sensory disturbances after a latency and insidious neuronal loss.
Dynamic nectar replenishment in flowers of Penstemon (Scrophulariaceae)
Authors: Castellanos Maria Clara , Wilson Paul , Thomson James D.
Published: February 2008

Plants that experience variation in pollinator visitation rates or fluctuations in weather conditions may be expected to have evolved homeostatic mechanisms that regulate their nectar offerings, thereby providing a more constant reward to the pollinators. A limited degree of such nectar homeostasis is reported here for Penstemon. First, nectar removal stimulates replenishment: when nectar was removed hourly for 6 h from P. speciosus, twice as much nectar was secreted cumulatively as when nectar was removed only at the beginning and end of the same 6‐h period. Second, replacing artificial nectar in the nectaries of P. speciosus prevents replenishment. Third, the hummingbird‐adapted P. barbatus made more nectar before leveling off than the bee‐adapted P. strictus. Our work and previous studies with other plants imply mechanisms for dynamic regulation of nectar offerings, at least within broad limits. We speculate about the proximate physiology underlying this behavior and its evolutionary significance.
Molecular phylogenetics of Caryophyllales based on nuclear 18S rDNA and plastid rbcL, atpB, and matK DNA sequences
Authors: Cuénoud Philippe , Savolainen Vincent , Chatrou Lars W. , Powell Martyn , Grayer Renée J. , Chase Mark W.
Published: February 2008

To study the inter‐ and infrafamilial phylogenetic relationships in the order Caryophyllales sensu lato (s.l.), ∼930 base pairs of the matK plastid gene have been sequenced and analyzed for 127 taxa. In addition, these sequences have been combined with the rbcL plastid gene for 53 taxa and with the rbcL and atpB plastid genes as well as the nuclear 18S rDNA for 26 taxa to provide increased support for deeper branches. The red pigments of Corbichonia, Lophiocarpus, and Sarcobatus have been tested and shown to belong to the betacyanin class of compounds. Most taxa of the order are clearly grouped into two main clades (i.e., “core” and “noncore” Caryophyllales) which are, in turn, divided into well‐defined subunits. Phytolaccaceae and Molluginaceae are polyphyletic, and Portulacaceae are paraphyletic, whereas Agdestidaceae, Barbeuiaceae, Petiveriaceae, and Sarcobataceae should be given familial recognition. Two additional lineages are potentially appropriate to be elevated to the family level in the future: the genera Lophiocarpus and Corbichonia form a well‐supported clade on the basis of molecular and chemical evidence, and Limeum appears to be separated from other Molluginaceae based on both molecular and ultrastructural data.
A trnL‐F cpDNA sequence study of the Condamineeae‐Rondeletieae‐Sipaneeae complex with implications on the phylogeny of the Rubiaceae
Authors: Rova Johan H. E. , Delprete Piero G. , Andersson Lennart , Albert Victor A.
Published: February 2008

DNA sequences from the chloroplast trnL‐F region of 154 Rubiaceae and 11 outgroup taxa were analyzed cladistically. An emphasis was placed on the tribes Rondeletieae, Sipaneeae, and Condamineeae. Sipaneeae are not close to Rondeletieae and belong in the Ixoroideae. There is no support for a widely distributed Rondeletieae in a broad sense. Instead, Rondeletieae sensu stricto form an almost entirely Antillean clade. Support was found for the separation of Arachnothryx, Rogiera, Roigella, and Suberanthus from Rondeletia. The Guettardeae as well as Gonzalagunia are found close to a complex formed by Arachnothryx, Javorkaea, and Rogiera. Condamineeae, in a strict sense, belongs in the Ixoroideae. A number of Rondeletieae genera should be transferred to Condamineeae or other parts of Ixoroideae. Support is found for an emended tribe Naucleeae, comprising several genera with spherical pseudanthia. For the first time, tribal or subfamilial affiliation based on molecular sequence data is suggested for Allenanthus, Blepharidium, Chione, Coutaportla, Dolichodelphys, Mazaea, Neobertiera, Neoblakea, Phialanthus, Phyllacanthus, Phyllomelia, Schmidtottia, and Suberanthus.
A new rain‐operated seed dispersal mechanism in Bertolonia mosenii (Melastomataceae), a Neotropical rainforest herb
Authors: Pizo Marco A. , Morellato L. Patrícia C.
Published: February 2008

Although widespread among fungi, lichens, liverworts, and mosses, seed dispersal mechanisms operated by rain are unusual among flowering plants. Generally speaking, two mechanisms are involved in seed dispersal by rains: the splash‐cup and the springboard. Here we describe a new seed dispersal mechanism operated by rain in a Neotropical rainforest herb Bertolonia mosenii Cogniaux (Melastomataceae). The study was carried out at the lowland Atlantic rainforest, southeastern Brazil. We experimentally demonstrate that rain is necessary to release the seeds from the capsules through what we call “squirt‐corner” seed dispersal mechanism: when a raindrop strikes the mature fruit, the water droplet forces the seeds outward to the angles (corners) of the triangular capsule and the seeds are released. As far as we know squirt‐corner represents a new rain‐operated seed dispersal mechanism, and a novel seed dispersal mode both for Melastomataceae and for flowering plants from Neotropical forests.
“To see … Heaven in a Wild Flower….”: Teaching botany in the 21st century
Authors: Richards Jennifer H. , Lee David W.
Published: February 2008

Submitted by Spencer C. H. Barrett, Book Review Editor
Thrips pollination of the dioecious ant plant Macaranga hullettii (Euphorbiaceae) in Southeast Asia
Authors: Moog Ute , Fiala Brigitte , Federle Walter , Maschwitz Ulrich
Published: February 2008

Discussion about thrips (Thysanoptera) as main pollinators has been controversial in the past because thrips do not fit the preconception of an effective pollinator. In this study, we present evidence for thrips pollination in the dioecious pioneer tree genus Macaranga (Euphorbiaceae). Macaranga hullettii is pollinated predominantly by one thrips species, Neoheegeria sp. (Phlaeothripidae, Thysanoptera). As a reward for pollinators, the protective floral bracteoles function as breeding sites for thrips and trichomal nectaries on the adaxial surface of the floral bracteoles provide alimentation. Flowering phenology of both staminate and pistillate trees was highly synchronized within 3–4 wk periods. In contrast to pistillate trees, staminate trees start to breed the thrips inside the developing inflorescences ∼2 wk before anthesis. Breeding of Neoheegeria sp. in the laboratory indicates that the thrips development is completed within ∼17 d. Thus, staminate trees offer breeding sites for one thrips generation until the onset of pollen presentation. Intraspecific pollen transfer by thrips was proved by pollen loads of thrips taken from receptive pistillate inflorescences of M. hullettii. Bagging experiments of different mesh sizes showed that seed set reached almost the level of open‐pollinated flowers when exclusively tiny insects like thrips were able to enter the net bags, but no apomictic seed set occurred when no insect access was given to the flowers.
The consequences of rewardlessness in orchids: reward‐supplementation experiments with Anacamptis morio (Orchidaceae)
Authors: Smithson Ann
Published: February 2008

Pollinators are expected to respond to low reward availability in an inflorescence by visiting fewer flowers before departure, thus potentially causing reduced visitation, but also reduced geitonogamous selfing. I tested this hypothesis using Anacamptis morio, an orchid that does not reward its pollinators. Supplementation of inflorescences with artificial nectar did not result in an increase in fruit set on supplemented inflorescences compared to control inflorescences and tended to reduce pollinia removal. Supplementation resulted in reduced fruit quality, but there was no evidence that this was as a result of inbreeding depression. Behavioral experiments showed that pollinating bumble bees, as predicted, visited more flowers on supplemented inflorescences. Bumble bees also deposited more self‐pollen on supplemented inflorescences, but this was marginally significant. Bumble bee queens removed significantly more pollinia from control inflorescences, while Bombus terrestris and B. lucorum workers did not. I conclude that while pollinators behaved as predicted, there was weak evidence that pollinia removal, pollen deposition, and fruit set followed the predictions of the hypothesis. I argue that this was probably because some pollinators were more efficient at removing and depositing pollen on control inflorescences, while others were not.
Why does the flower stalk of Pulsatilla cernua (Ranunculaceae) bend during anthesis?
Authors: Huang Shuang‐Quan , Takahashi Yoshitaka , Dafni Amots
Published: February 2008

Flower stalks of Pulsatilla cernua, an early spring herb in north temperate Asia, changed position from erect to pendulous and back to erect during 6–10 d anthesis. We tested three possible explanations for this movement. Our results showed that (1) this movement is unlikely to be a mechanism to attract pollinators or enhance pollen output, because no pollinator preference was observed between erect and pendulous flowers and we found no buzz‐pollination in this species; (2) hand self‐pollination yielded higher seed set than open pollination in the field, but spontaneous selfing rarely occurred. Among open‐pollinated flowers, seed set was depressed by emasculation, indicating that in the presence of insects, self‐pollen provided reproductive assurance in this protogynous and self‐compatible species. However, the change in flower orientation cannot be explained as reproductive assurance in that even self‐pollination largely depended on pollinator visits rather than gravity. (3) A pollen germination experiment indicated that pollen damage by water is serious in this species. We deduced that the bending of the flower stalk during anthesis was to avoid rain damage to pollen grains in this species. During the 3–6 d period of pollen presentation, the petals elongated and were covered with unwettable hairs. Together with flower stalk movement, this was enough to protect the organs inside the flower from rain. This movement of the flower stalk seems to be important to maintain pollen viability in a rainy habitat with a scarcity of pollinators.
Quantifying latitudinal clines to light responses in natural populations of Arabidopsis thaliana (Brassicaceae)
Authors: Stenøien Hans K. , Fenster Charles B. , Kuittinen Helmi , Savolainen Outi
Published: February 2008

Evidence of adaptation in Arabidopsis thaliana (Brassicaceae) phenotypic traits has rarely been shown. We demonstrate latitudinal clines in two A. thaliana traits: hypocotyl responses to red and far‐red light. Natural populations of A. thaliana were sampled along a latitudinal gradient from southern to northern Norway. Seeds from maternal families within each population were subjected to 1 wk of constant red, far‐red, blue, white, and dark treatments. Hypocotyl lengths were measured for each maternal family within each population. Significant variability within and among populations in hypocotyl responses for the various treatments was found. There was a significant latitudinal cline in hypocotyl responses for red and far‐red treatments, with northern populations being more de‐etiolated than southern populations. These results suggest that northern populations are more responsive to red and far‐red light than southern populations. Thus, differentiation of seedling traits in natural populations of A. thaliana seems in part to be mediated by the phytochrome pathway. There was no correlation between hypocotyl responses and flowering time for any treatment. This suggests that flowering time variability and variability in hypocotyl responses may not be governed by genes shared between the pathways, such as those involved in photoreception or the circadian clock.
Phenology and demography of two species of Botrychium (Ophioglossaceae)
Authors: Johnson‐Groh Cindy L. , Lee Jennifer M.
Published: February 2008

Temporal and demographic aspects of the growth of Botrychium gallicomontanum and B. mormo were studied for 2 yr. A total of 219 B. gallicomontanum and 412 B. mormo plants were monitored in a prairie and maple–basswood forest, respectively. Growth events were divided into four stages: leaf emergence, leaf separation, spore release, and senescence. Botrychium gallicomontanum emerged in April, peaked during the first week of June, and declined rapidly. The largest plants were found in late June and early July with a mean peak trophophore size of 4.0 ± 1.8 cm. Botrychium mormo emerged in June, and the population size peaked in early July. The largest plants occurred late in August with a mean peak trophophore size of 3.0 ± 1.1 cm. The mean season span, or period of emergence aboveground annually, for B. gallicomontanum and B. mormo was 7.7 ± 2.4 and 11.9 ± 3.5 wk, respectively. Late‐emerging plants produced spores in shorter periods. The separation stage was prolonged in B. gallicomontanum plants, whereas B. mormo plants had a much longer separation stage. Phenological differences are related to different habitat parameters of grassland and forest. Understanding the phenology of these rare species will help us more accurately predict the impact of management practices.
Variation in grazing tolerance among three tallgrass prairie plant species
Authors: Damhoureyeh Said A. , Hartnett David C.
Published: February 2008

Three tallgrass prairie plant species, two common perennial forbs (Artemisia ludoviciana and Aster ericoides [Asteraceae]) and a dominant C4 perennial grass (Sorghastrum nutans) were studied under field and greenhouse conditions to evaluate interspecific variation in grazing tolerance (compensatory growth capacity). Adaptation to ungulate grazing was also assessed by comparing defoliation responses of plants from populations with a 25‐yr history of no grazing or moderate ungulate grazing. Under field conditions, all three species showed significant reductions in shoot relative growth rates (RGR), biomass, and reproduction with defoliation. In the two forbs, clipping resulted in negative shoot RGR and reductions in both number and length of shoot branches per ramet. Sorghastrum nutans maintained positive RGR under defoliation due to a compensatory increase in leaf production. Defoliation reduced rhizome production in A. ericoides and S. nutans, but not in A. ludoviciana. Clipping significantly reduced sexual reproductive allocation in all three species, although S. nutans showed a smaller reduction than the forbs. All three species showed similar responses to defoliation in burned and unburned sites. Under greenhouse conditions, a similar clipping regimen resulted in smaller reductions in growth and reproduction than those observed in the field. For all three species, the grazing tolerance indices calculated under natural field conditions were significantly lower than those estimated from greenhouse‐grown plants, and the interspecific patterns of grazing tolerance were different. Aster ericoides exhibited the highest overall defoliation tolerance under greenhouse conditions, followed by S. nutans. Artemisia ludoviciana, the only study species that is typically not grazed by ungulates in the field, showed the lowest grazing tolerance. In the field experiment S. nutans showed the highest grazing tolerance and the two forbs had similar low tolerance indices. These patterns indicate that, despite high compensatory growth potential, limited resource availability and competition in the field significantly reduce the degree of compensation and alter interspecific differences in grazing tolerance among prairie plants. In all three species, defoliation suppressed sexual reproduction more than growth or vegetative reproduction. Significant interactions between plant responses to defoliation and site of origin (historically grazed or ungrazed sites) for some response variables (root/shoot ratios, rhizome bud initiation, and reproductive allocation) indicated some degree of population differentiation and genetic adaptation in response to a relatively short history of ungulate grazing pressure. The results of this study indicate that patterns of grazing tolerance in tallgrass prairie are both genetically based and also environmentally dependent.
Group II introns as phylogenetic tools: structure, function, and evolutionary constraints
Authors: Kelchner Scot A.
Published: February 2008

Group II introns comprise the majority of noncoding DNA in many plant chloroplast genomes and include the commonly sequenced regions trnK/matK, the rps16 intron, and the rpl16 intron. As demand increases for nucleotide characters at lower taxonomic levels, chloroplast introns may come to provide the bulk of plastome sequence data for assessment of evolutionary relationships in infrageneric, intergeneric, and interfamilial studies. Group II introns have many attractive properties for the molecular systematist: they are confined to organellar genomes in eukaryotes and the majority are single‐copy; they share a well‐defined and empirically tested secondary and tertiary structure; and many are easily amplified due to highly conserved sequence in flanking exons. However, structure‐linked mutation patterns in group II intron sequences are more complex than generally supposed and have important implications for aligning nucleotides, assessing mutational biases in the data, and selecting appropriate models of character evolution for phylogenetic analysis. This paper presents a summary of group II intron function and structure, reviews the link between that structure and specific mutational constraints in group II intron sequences, and discusses strategies for accommodating the resulting complex mutational patterns in subsequent phylogenetic analyses.
Phylogeny of seed plants based on evidence from eight genes
Authors: Soltis Douglas E. , Soltis Pamela S. , Zanis Michael J.
Published: February 2008

Relationships among the five groups of extant seed plants (cycads, Ginkgo, conifers, Gnetales, and angiosperms) remain uncertain. To explore relationships among groups of extant seed plants further and to attempt to explain the conflict among molecular data sets, we assembled a data set of four plastid (cpDNA) genes (rbcL, atpB, psaA, and psbB), three mitochondrial (mtDNA) genes (mtSSU, coxI, and atpA), and one nuclear gene (18S rDNA) for 19 exemplars representing the five groups of living seed plants. Analyses of the combined eight‐gene data set (15 772 base pairs/taxon) with maximum parsimony (MP), maximum likelihood (ML), and Bayesian approaches reveal a gymnosperm clade that is sister to angiosperms. Within the gymnosperms, a conifer clade includes Gnetales as sister to Pinaceae. Cycads and Ginkgo are either successive sisters to this conifer clade (including Gnetales) or a clade that is sister to conifers and Gnetales. All analyses of the mtDNA partition and ML analyses of the nuclear partition yield very similar topologies. However, MP analyses of the combined cpDNA genes place Gnetales as sister to all other seed plants with strong bootstrap support, whereas ML and Bayesian analyses of the cpDNA data set place Gnetales as sister to Pinaceae. Maximum parsimony and ML analyses of first and second codon positions of the cpDNA partiation also place Gnetales as sister to Pinaceae. In contrast, MP analyses of third codon positions place Gnetales as sister to other seed plants, although ML analyses of third codon positions place Gnetales with Pinaceae. Thus, most of the discrepancies in seed plant topologies involve third codon positions of cpDNA genes. The likelihood ratio (LR) and Shimodaira‐Hasegasa (SH) tests were applied to the cpDNA data. The preferred topology based on the LR test is that Gnetales are sister to Pseudotsuga. The SH test based on first and second codon and all three codon positions indicated that there is no significant difference between the best topology (Gnetales sister to Pseudotsuga) and Gnetales sister to a conifer clade. However, there is a significant difference between the best topology and topologies in which Gnetales are sister to the rest of the seed plants or Gnetales sister to angiosperms.
The phylogeny and a new classification of the gingers (Zingiberaceae): evidence from molecular data
Authors: Kress W. John , Prince Linda M. , Williams Kyle J.
Published: February 2008

The pantropical Zingiberaceae is the largest family in the order Zingiberales with 53 genera and over 1200 species. Classifications of the family first proposed in 1889 and refined by others since that time recognize four tribes (Globbeae, Hedychieae, Alpinieae, and Zingibereae) based on morphological features, such as number of locules and placentation in the ovary, development of staminodia, modifications of the fertile anther, and rhizome‐shoot‐leaf orientation. New phylogenetic analyses based on DNA sequences of the nuclear internal transcribed spacer (ITS) and plastid matK regions suggest that at least some of these morphological traits are homoplasious and three of the tribes are paraphyletic. The African genus Siphonochilus and Bornean genus Tamijia are basal clades. The former Alpinieae and Hedychieae for the most part are monophyletic taxa with the Globbeae and Zingibereae included within the latter. The results of these phylogenetic investigations are used to propose a new classification of the Zingiberaceae that recognizes four subfamilies and four tribes: Siphonochiloideae (Siphonochileae), Tamijioideae (Tamijieae), Alpinioideae (Alpinieae, Riedelieae), and Zingiberoideae (Zingibereae, Globbeae). Morphological features congruent with this classification and the taxonomic status of various monotypic genera are discussed.
The phylogenetic utility of nucleotide sequences of sorbitol 6‐phosphate dehydrogenase inPrunus(Rosaceae)
Authors: Bortiri Esteban , Oh Sang‐Hun , Gao Fang‐You , Dan Potter
Published: February 2008

Sequences froms6pdh,a gene that encodes sorbitol‐6‐phosphate dehydrogenase in the Rosaceae, are used to reconstruct the phylogeny of 22 species ofPrunus. Thes6pdhsequences alone and in combination with previously published sequences of the internal transcribed spacer (ITS) and the cpDNAtrnL‐trnFspacer are analyzed using parsimony and maximum likelihood methods. Both methods reconstructed the same phylogeny whens6pdhsequences are used alone and in combination with ITS andtrnL‐trnF,and the topology is in agreement with previous studies that used a larger sample size. Thes6pdhsequences have about twice as many informative sites as ITS. A molecular clock is rejected fors6pdh,most likely due to greater rates of evolution in subgeneraPadusandLaurocerasusthan in the rest of the genus. Phylogenetic reconstruction ofPrunusas determined by analysis of the combined data set suggests an early split into two clades. One is composed of subgeneraCerasus,Laurocerasus, andPadus. The second includes subgeneraAmygdalus,Emplectocladus, andPrunus. Species of sectionMicrocerasus(formerly in subgenusCerasus) are nested within subgenusPrunus. The order of branching and relationships among early diverging lineages is weakly supported, as a result of very short branches that may indicate rapid radiation.
Inflorescence development in a high‐altitude annual Mexican teosinte (Poaceae)
Authors: Orr Alan R. , Mullen Kevin , Klaahsen Darcey , Sundberg Marshall D.
Published: February 2008

Some have postulated that highland Mexican maize was derived from an ancient high‐altitude teosinte and that later introgression between the two taxa occurred. We used scanning electron microscopy to examine the inflorescence development in both the tassel and ear of a high‐altitude Toluca teosinte. One of the most interesting observations was the presence of atypical multiranked orthostiches in the central spike of some male Toluca teosinte inflorescences. Most tassels exhibited a central spike with a pure, four‐ranked, tetrastichous phyllotaxy or an intermediate (distichous/tetrastichous) phyllotaxy. A few A1 tassels had a more typical distichous (two‐ranked) central spike. Most ears showed the two‐rank condition expected for teosintes. However, three ears displayed an intermediate (distichous/tristichous or distichous/ tetrastichous) phyllotaxy and one ear was tetrastichous. Our analysis of spikelet and floret development in all Toluca inflorescences revealed a pattern similar to that in landrace and U.S. maize, as well as to their close relatives, the teosintes. We suggest that this investigation may reveal inflorescence development in a natural maize‐teosinte hybrid. This study further supports our hypothesis that both maleness and femaleness in the Zea inflorescences are derived from a common developmental pathway and underpins a proposal that andropogonoid grasses share a common pattern of inflorescence development.
The evolution of anther morphology in orchids: incumbent anthers, superposed pollinia, and the vandoid complex
Authors: Freudenstein John V. , Harris Elizabeth M. , Rasmussen Finn N.
Published: February 2008

The anther is the source of several of the principal characters traditionally used for classification in Orchidaceae, especially in Epidendroideae. In particular, anther and pollinium orientation are important, but little‐studied characters; it is not known whether various instances of these states are achieved in the same way. We examined variation in anther and pollinium orientation in Epidendroideae and Vanilloideae using anatomical sections of columns at successive ontogenetic stages and related the observed changes to the final anther morphology to reexamine our homology hypotheses for these characters. Anther bending in vanilloids is achieved primarily by massive expansion of the connective. In nonvandoid epidendroids it is the result of column elongation and tipping of the mature anther, while in vandoids it is due to a redirection of growth in very early ontogenetic stages. Superposed pollinia result from a reorientation of developing thecae; those is Sobralia result from incurving of the thecae, while vandoids have thecae that are directed outward (latrorse). Contrasting ontogenetic and phylogenetic patterns suggest heterochronic changes in these characters, especially in vandoids. These observations allow us to further refine character states that are crucial to our understanding of orchid relationships.