bluuebunny/crossref_metadata_2025 huggingface dataset:
RENAL DENERVATION CAUSES CHRONIC HYPOTENSION IN RATS: ROLE OF Β1‐ADRENOCEPTOR ACTIVITY
Authors: Jacob Frédéric , LaBine Brian G , Ariza Pilar , Katz Stephen A , Osborn John W
Published: March 2005

1. Renal denervation (RDNX) chronically lowers mean arterial pressure (MAP) in normal rats but mechanisms leading to this hypotensive response remain unknown.

2. We hypothesized that this sustained decrease in arterial pressure was because of a loss of β1‐adrenoceptor mediated renin secretion. Male Sprague‐Dawley rats were assigned to sham (SHAM; n = 9), unilateral (UniRDNX; n = 9), or bilateral (RDNX; n = 10) renal denervation groups and instrumented for telemetric MAP measurements, plasma renin concentration (PRC) measurements and intravenous infusion. Twenty‐four h MAP, heart rate, sodium and water balances were recorded 5 days before, 3 days during and 3 days after 1‐adrenoceptor blockade with atenolol.

3. The 5‐day control MAP was significantly lower in RDNX (97 ± 1 mmHg) compared to SHAM (105 ± 2 mmHg) and UniRDNX (102 ± 2 mmHg) rats. No significant differences in basal PRC were observed between RDNX (2.2 ± 0.3 ngAng1/mL per h), UniRDNX (2.6 ± 0.4 ng/Ang1/mL per h) and SHAM (2.6 ± 0.4 ngAng1/mL per h) rats. By day 1 of atenolol, PRC was significantly lower in UniRDNX rats (1.8 ± 0.2 ngAg1/mL per h) compared to control values, but was unchanged during atenolol infusion in the other groups. By day 3 of atenolol, MAP was significantly decreased in all groups, but the absolute levels of MAP remained statistically different between RDNX (87 ± 1 mmHg) and SHAM (91 ± 1 mmHg) groups.

4. We conclude that the arterial pressure lowering effect of RDNX is not solely dependent on the loss of neural control of renin release.
CARDIOVASCULAR ADAPTATIONS IN RATS SUBMITTED TO A RESISTANCE‐TRAINING MODEL
Authors: Barauna Valerio G , Junior Miguel Luis B , Costa Rosa Luis Fernando BP , Casarini Dulce E , Krieger José Eduardo , Oliveira Edilamar M
Published: March 2005

1. The present study sought to evaluate cardiovascular adaptations, such as blood pressure (BP), heart rate (HR) and cardiac hypertrophy, to resistance training (RT) in a rat model.

2. The training protocol consisted of four sets of 10–12 repetitions of the squat exercise performed at 65–75% of one repetition maximum (1RM) over 4 weeks. Animals were randomly divided into three groups: control (n = 8, CO), electrically stimulated (n = 8, ES) and trained (n = 8, TR; also electrically stimulated). Blood pressure and HR were measured by a direct method in conscious rats after the training period.

3. All groups began with similar 1RM and 1RM/bodyweight (BW) ratio, however, at the end of the protocol only the TR group was different from the beginning (56% and 50%, respectively; both P < 0.01). The CO and ES groups had similar values for cardiac chambers weight/BW ratio, HR and diastolic, systolic and mean BP. Left ventricular hypertrophy (LVH) determined by the left ventricle (LV) weight/BW ratio was increased in the TR group (12%) when compared to CO (P < 0.01) or ES groups (P < 0.01). No changes were found in the weights of the atrium or right ventricle. Diastolic (14%) and mean BP (13%) were lower in the TR group (P < 0.05), whereas systolic BP and HR remained unchanged.

4. Collectively these results demonstrate that the rat RT model used is associated with significant development of cardiac hypertrophy and lowering of resting BP. These cardiovascular adaptations seem to a result of the training exercise and not influenced by stress since circulating catecholamine levels and adrenal gland weights remained unchanged in all groups.
DIFFERENTIAL REGULATION OF ANGIOTENSIN II RECEPTORS DURING RENAL INJURY AND COMPENSATORY HYPERTROPHY IN THE RAT
Authors: Joly Emma , Nonclercq Denis , Caron Nathalie , Mertens Jeannine , Flamion Bruno , Toubeau Gerard , Kramp Ronald , Bouby Nadine
Published: March 2005

1. The renin‐angiotensin system may be involved in the compensatory adaptations occurring after the reduction of renal mass and during the consecutive changes leading to chronic renal failure. We therefore investigated the regulation of angiotensin II receptors in two models of renal hypertrophy in the rat: hypertrophy following uninephrectomy (UNx) or subtotal nephrectomy (STNx). The level of angiotensin type 1 (AT1A‐R and AT1B‐R) and type 2 (AT2‐R) receptor mRNA was quantified by competitive reverse transcription‐polymerase chain reaction (RT‐PCR) in specific renal zones and the intrarenal distribution of angiotensin II receptors was analysed by immunohistochemistry.

2. In the UNx rats, AT1‐R mRNA expression was not modified in the cortex or in the inner stripe of the outer medulla of the residual kidney at any time after the surgery (1, 4 and 12 weeks). In contrast, AT1‐R mRNA expression was significantly reduced in these zones in STNx rats (−33% and −40%, respectively). This downregulation was organ‐specific, as AT1‐R mRNA levels were not modified in the liver. The proportions of AT1‐R subtype (AT1A and AT1B) mRNA were unchanged by UNx or STNx. Very low levels of AT2‐R mRNA were found in the cortex of all groups. Immunostaining revealed a similar localization of AT1‐R in mesangial cells, proximal tubule, basolateral membrane of thick ascending limb, in both models of hypertrophy. AT1‐R labelling was also detected in the apical membrane of intercalated cells of cortical collecting ducts.

3. This differential mRNA expression of angiotensin II receptors during compensatory hypertrophy and renal injury suggests that the development of renal hypertrophy is independent of AT1‐R and AT2‐R gene expression levels.
EFFECT OF ZINC SULPHATE AND ZINC METHIONINE ON GROWTH, PLASMA GROWTH HORMONE CONCENTRATION, GROWTH HORMONE RECEPTOR AND INSULIN‐LIKE GROWTH FACTOR‐I GENE EXPRESSION IN MICE
Authors: Yu Ze‐Peng , Le Guo‐Wei , Shi Yong‐Hui
Published: March 2005

1. The current experiment was conducted to investigate the effect of zinc sulphate (ZnSO4) and zinc methionine (Zn‐Met) on growth and their effect on plasma growth hormone (GH) concentration, growth hormone receptor (GHR) and insulin‐like growth factor I (IGF‐I) mRNA expression in mice.

2. Ninety male KunMing (KM) mice were randomly divided into three treatments. The control group was fed on a basal diet containing 11.67 mg/kg of zinc. The ZnSO4 group and Zn‐Met group were fed on the diets supplemented with ZnSO4 or Zn‐Met at 30 mg/kg (containing zinc of 40.05 and 40.75 mg/kg, respectively). The mice were offered the test diets for 10 days. Weight gains and food intake were measured at the end of the experiment, zinc contents in liver and serum were determined using atomic absorption spectrophotometry; GH was determined by radioimmunoassay, the levels of GHR and IGF‐I mRNA were determined with reverse transcript polymerase chain reaction.

3. Both ZnSO4 and Zn‐Met enhanced weight gain and food intake in the mice, Zn‐Met improved the growth and food intake more effectively than ZnSO4 did (P < 0.05). The both forms of zinc had no effect on GH and the level of GHR mRNA expression (P > 0.05) and they up‐regulated the expression of IGF‐I mRNA (P < 0.05). As compared to ZnSO4, Zn‐Met enhanced the level of IGF‐I mRNA significantly (P < 0.05).

4. Both ZnSO4 and Zn‐Met had no effect on plasma GH and the expression of GHR mRNA, but they enhanced the expression of IGF‐I mRNA. Zinc methionine enhanced the weight gain and up‐regulated IGF‐I mRNA expression more effectively than ZnSO4.
RESISTANCE TO EXCESSIVE BODYWEIGHT GAIN IN RISPERIDONE‐INJECTED RATS
Authors: Ota Miyuki , Mori Keiji , Nakashima Akira , Kaneko Yoko S , Takahashi Hisahide , Ota Akira
Published: March 2005

1. The present study was carried out to explain the resistance of rats injected subcutaneously with risperidone, the atypical antipsychotic drug, for 21 consecutive days at 0.1 mg/kg per day (a dose equivalent to the one used for patients) to result in an excessive bodyweight despite the increase in diet‐uptake in rats against risperidone‐induced decrease in body temperature.

2. Rectal temperature measurements were made in 8‐week‐old male Sprague‐Dawley rats maintained under standard laboratory conditions using a 12 h daylight cycle. A s.c. injection of risperidone (0.05 mg/kg) produced hypothermia in rats, which was observed during the daily injection for 21 consecutive days.

3. Sera, white and brown adipose tissues, skeletal muscle and liver were extracted from 8‐week‐old male Sprague‐Dawley rats injected subcutaneously with risperidone (0.01 or 0.1 mg/kg per day) or a vehicle for 21 consecutive days. Serum levels of lipids, ketones and thyroid hormone were measured. The mRNA expression levels in these tissues and organs of the genes encoding the substances involved in heat production and/or lipid metabolism were investigated by using quantitative real‐time polymerase chain reaction amplification.

4. Serum nonesterified fatty acid levels in risperidone 0.1 mg/kg per day s.c. injected rats were significantly lower than those in vehicle‐injected ones. Serum β‐hydroxybutyrate levels in risperidone‐injected rats tended to decrease compared with those in vehicle‐injected ones. The serum level of neither triiodothyronine nor thyroxine was affected by risperidone s.c. injection at the doses examined, although their values were within normal limits.

5. Risperidone injection (0.1 mg/kg per day) for 21 consecutive days upregulated mRNA expressions in white adipose tissue of uncoupling protein 3 which dissipates energy as heat; peroxisome proliferator‐activated receptor (PPAR) γ coactivator 1α which activates mitochondrial biogenesis to expand the oxidative machinery; and PPARα which is necessary for the fat‐depletion of adipocytes for thermogenesis. The mRNA of lipogenic enzymes (acetyl‐CoA carboxylase α, fatty‐acid synthase and glycerol‐3‐phosphate acyltransferase), hormone sensitive lipase and β1‐adrenoceptor were also enhanced in white adipose tissue by the injection of 0.1 mg/kg per day risperidone.

6. These findings suggest that the materials for heat generation in white adipose tissue would be readily supplied, which in turn would reduce a storage of lipids in white adipose tissue resulting in the lower rate of bodyweight gain of rats.
OPTICAL IMAGING OF RESPIRATORY NEURON ACTIVITY FROM THE DORSAL VIEW OF THE LOWER BRAINSTEM
Authors: Onimaru Hiroshi , Homma Ikuo
Published: March 2005

1. We visualized respiratory‐related neuron network activity in the dorsal part of the pons and medulla of an in vitro preparation from newborn rats by optical recordings using a voltage‐sensitive dye. We measured optical signals from several seconds before to several seconds after the inspiratory phase using the inspiratory motor nerve discharge as the trigger signal and we averaged the optical signals of 20–50 respiratory cycles to obtain an optical image correlating specifically to inspiratory activity.

2. Four areas that were excited or inhibited corresponding to the respiratory cycles were detected. (i) The most rostral activity was in the rostral and lateral parts of the pons, with activity mainly in the inspiratory phase, corresponding to the pontine‐respiratory group. (ii) In the midpontine level, inspiratory activity followed by long‐lasting hyperpolarization appeared in the midlateral parts. This part was presumed to reflect activity in the locus coeruleus. The hyperpolarization became almost negligible after treatment with the α‐adrenergic antagonist, phentolamine. (iii) In the dorsal medulla, the predominantly inspiratory activity was detected at the rostral level of the area postrema. This part was considered to reflect activity mainly of the hypoglossal nucleus. (iv) At a similar level, we also detected weak and disperse inspiratory activity extending more laterally and caudally than that of the hypoglossal nucleus activity. This might reflect activity of the dorsal respiratory group.

3. In conclusion, the present optical recording study revealed that the dorsal part of the lower brainstem in the in vitro preparation is noticeably active as well as the ventral part shown in the previous study. This method is very useful for analysis of pharmacological properties, as well as the spatio‐temporal pattern of respiratory‐related network activity in the brainstem.
ACTIVE ROLE FOR THE VASCULATURE IN THE DELIVERY OF INSULIN TO SKELETAL MUSCLE
Authors: Vincent Michelle A , Clerk Lucy H , Rattigan Stephen , Clark Michael G , Barrett Eugene J
Published: March 2005

1. In the 80+ years since insulin's discovery, an enormous amount of literature has accumulated relating to its actions on body fat, glucose and protein metabolism. In particular, skeletal muscle has been extensively studied because of its major role as a site of insulin‐mediated glucose disposal. Liver and adipose tissue are two other extensively studied sites of insulin action. Much less investigation has been directed towards delineating insulin's actions on cells other than myocytes, adipocytes and hepatocytes.

2. Over the past 5–10 years it has become increasingly evident that insulin exerts important actions on vascular cells. Here, we review evidence that insulin's action within muscle may be very much regulated by its ability to transit the vasculature to access the interstitial fluid (and hence the myocyte insulin receptor). Surprisingly little is known regarding the regulation of vascular events that first bring insulin to the capillary endothelium within muscle, whence presumably it transits from the vascular to the interstitial space. Recent studies suggest that insulin can increase blood flow and also influence the distribution of blood flow within skeletal muscle, potentially therefore regulating its own delivery to the capillary endothelium. Beyond insulin's ability to access the vascular lumen within skeletal muscle microvasculature lies the issue of its passing the endothelial barrier. Even less is known about the processes involved in insulin's actual transit across the endothelium. Available data do not clearly indicate whether this is a saturable, receptor‐mediated process or a passive‐diffusion pathway. Also, whether insulin in any manner regulates its own transit across the endothelium or its clearance via the lymphatic system is entirely unknown.

3. The aim of the present review is to identify areas where knowledge is deficient and highlight hypotheses which may lead to a better understanding of the coordinated relationship between insulin's vascular actions within muscle and its metabolic actions in that tissue. Even so, there is now sufficient evidence to indicate that insulin's vascular action within skeletal muscle is a major regulatory locus for its insulin mediated glucose disposal.
USE OF GLUT‐4 NULL MICE TO STUDY SKELETAL MUSCLE GLUCOSE UPTAKE
Authors: Charron Maureen J , Gorovits Naira , Laidlaw J Skye , Ranalletta Mollie , Katz Ellen B
Published: March 2005

1. The present review focuses on the effects of varying levels of GLUT‐4, the insulin‐senstive glucose transporter, on insulin sensitivity and whole body glucose homeostasis.

2. Three mouse models are discussed including myosin light chain (MLC)‐GLUT‐4 mice which overexpress GLUT‐4 specifically in skeletal muscle, GLUT‐4 null mice which express no GLUT‐4 and the MLC‐GLUT‐4 null mice which express GLUT‐4 only in skeletal muscle. Overexpressing GLUT‐4 specifically in the skleletal muscle results in increased insulin sensitivity in the MLC‐GLUT‐4 mice. In contrast, the GLUT‐4 null mice exhibit insulin intolerance accompanied by abnormalities in glucose and lipid metabolism. Restoring GLUT‐4 expression in skeletal muscle in the MLC‐GLUT‐4 null mice results in normal glucose metabolism but continued abnormal lipid metabolism.

3. The results of experiments using these mouse models demonstrates that modifying the expresssion of GLUT‐4 profoundly affects whole body insulin action and consequently glucose and lipid metabolism.
GLUCOSE PHOSPHORYLATION AS A BARRIER TO MUSCLE GLUCOSE UPTAKE
Authors: Fueger Patrick T
Published: March 2005

1. Glucose phosphorylation is the first irreversible step of the muscle glucose uptake pathway and is catalysed by a hexokinase isozyme.

2. While glucose transport is the primary barrier to muscle glucose uptake during basal conditions, glucose phosphorylation becomes an important barrier to muscle glucose uptake during stimulated conditions such as hyperinsulinaemia or exercise.

3. High fat feeding markedly impairs insulin‐ and exercise‐stimulated muscle glucose uptake. As hexokinase II overexpression corrects this dietary‐induced deficit during exercise, glucose phosphorylation is a site of impairment following high fat feeding.

4. Exercise is an important tool for diagnosing deficits in glucose phosphorylation.
INTERACTION OF PHYSIOLOGICAL MECHANISMS IN CONTROL OF MUSCLE GLUCOSE UPTAKE
Authors: Wasserman David H , Ayala Julio E
Published: March 2005

1. Control of glucose uptake is distributed between three steps. These are the rate that glucose is delivered to cells, the rate of transport into cells, and the rate that glucose is phosphorylated within these same cells. The functional limitations to each one of these individual steps has been difficult to assess because they are so closely coupled to each other. Studies have been performed in recent years using complex isotopic techniques or transgenic mouse models to shed new light on the role that each step plays in overall control of muscle glucose uptake.

2. Membrane glucose transport is a major barrier and glucose delivery and glucose phosphorylation are minor barriers to muscle glucose uptake in the fasted, sedentary state. GLUT‐4 is translocated to the muscle membrane during exercise and insulin‐stimulation. The result of this is that it can become so permeable to glucose that it is only a minor barrier to glucose uptake.

3. In addition to increasing glucose transport, exercise and insulin‐stimulation also increase muscle blood flow and capillary recruitment. This effectively increases muscle glucose delivery and by doing so, works to enhance muscle glucose uptake.

4. There is a growing body of data that suggests that insulin resistance to muscle glucose uptake can be because of impairments in any one or more of the three steps that comprise the process.
GANGLION BLOCKADE DOES NOT PREVENT CORTISOL‐INDUCED HYPERTENSION IN MAN
Authors: Williamson Paula M , Tam Sim Hom , Kelly John J , Whitworth Judith A
Published: March 2005

1. The aim of the present study was to assess the effect of ganglion blockade on blood pressure in cortisol treated human subjects.

2. Four healthy male subjects were treated with cortisol 80 mg/day for a 5‐day period. Ganglion blockade was achieved by intravenous trimethaphan.

3. Ganglion blockade did not significantly alter blood pressure in the pretreatment phase or on the last day of cortisol treatment.

4. Taken together with our previous observations that sympathetic activity is unaltered or reduced by cortisol, these results suggest that cortisol induced hypertension in humans is not a result of overactivity of the autonomic nervous system.
Management of tuberculous pleuritis: Can we do better?
Authors: WONG Poon‐Chuen
Published: March 2005

Abstract:  Management of patients with tuberculous pleuritis can be improved by establishing early diagnosis accurately, administering effective chemotherapy, and close monitoring of progress for early detection and prompt management of severe pleural inflammation in the hope of preventing or reducing subsequent residual pleural fibrosis. In addition to the conventional diagnostic tools, chemical markers, especially pleural fluid adenosine deaminase and interferon‐γ levels and new microbiological tests such as polymerase chain reaction and BACTEC culture of pleural biopsy specimens for Mycobacterium tuberculosis, can increase the diagnostic yield for tuberculous pleuritis. Indicators of the severity of pleural inflammation, including high pleural fluid tumour necrosis factor‐α and lysozyme levels, and low pleural fluid glucose and pH, can help to predict residual pleural fibrosis. It is likely that patients will require surgery: (i) complete drainage of pleural fluid for prevention; and (ii) pleurectomy for the treatment of residual pleural fibrosis.
Comparison of inhaled corticosteroid combined with theophylline and double‐dose inhaled corticosteroid in moderate to severe asthma
Authors: WANG Yan , WANG Chang‐Zheng , LIN Ke‐Xiong , QIAN Gui‐Sheng , ZHUO Wen‐Lei , LI Shu‐Ping , ZHAO Zhi‐Qiang , LIAO Xiu‐Qing , SONG Yun‐Xi
Published: March 2005

Objective:  Recent studies have found that theophylline exerts anti‐inflammatory and immunomodulatory effects. This study was performed to compare the efficacy of inhaled corticosteroids (ICS) combined with slow‐release theophylline (SRT) with that of double‐dose ICS in asthma control, anti‐inflammatory activity and safety.

Methodology:  In a randomized, open, parallel, control trial, 41 patients with asthma were randomly treated with either beclomethasone dipropionate 500 µg b.i.d. (BDP group) or a combination of BDP 250 µg b.i.d and SRT 0.2 g b.i.d. (SRT/BDP group) for 6 weeks. At the start and at the end of treatment, lung function testing and sputum induction were performed, and plasma cortisol levels were measured. Sputum was analyzed for cell differential counts and the interleukin (IL)‐5 level. Patients kept a record of peak expiratory flow (PEF), symptom score, and β2‐agonist use.

Results:  Significant increases in the morning and the evening PEF and FEV1 were observed (P < 0.05), together with an obvious reduction in symptom score and β2‐agonist use (P < 0.01). Significant decreases in the percentage eosinophils and IL‐5 level in induced sputum also occurred (P < 0.05). However, there was no difference between the two groups for all these parameters. There was no significant change in the plasma cortisol level for either group.

Conclusions:  Both ICS combined with SRT and double‐dose ICS had the same effect on asthma control, improving symptoms and ameliorating lung function. Both therapies had similar anti‐airway inflammatory effects and therapeutic safety. Combining SRT with ICS may allow a reduction in ICS dose when treating asthma.
The effect of N‐acetylcysteine on Clara cells and Clara cell 16 kDa protein in a murine model of allergen‐induced airway inflammation
Authors: NIE Xiaomeng , LI Qiang , CAI Gang , DAI Yimin , ZHANG Jun
Published: March 2005

Objective:  The aim of this study was to investigate the number of Clara cells and the production and secretion of Clara cell 16 kDa protein (CC16) in a murine model of allergen‐induced airway inflammation, as well as the effects of N‐acetylcysteine (NAC) on CC16 and Clara cell numbers, in order to determine the mechanism of the anti‐inflammatory effect of NAC.

Methodology:  BALB/c mice were divided into control, ovalbumin (OVA) and NAC groups. An allergen‐induced airway inflammation model (OVA group) was established by sensitizing and challenging mice with OVA. NAC was administered as an oral treatment. The number of Clara cells and the production of CC16 were determined by immunohistochemistry. The CC16 levels in bronchoalveolar lavage fluid (BALF) were determined by Western blotting.

Results:  The proportion of Clara cells in terminal and respiratory bronchioles significantly decreased in the OVA group compared to the control group (P < 0.01). NAC treatment did not change the proportion of Clara cells in the OVA group (P > 0.05). CC16 production by Clara cells in the OVA groups was significantly lower than that of the control group (P < 0.01), but was elevated following NAC treatment (P < 0.05). The CC16 level in BALF of the OVA group was lower than that of the control group (P < 0.01), but was elevated by NAC treatment (P < 0.05). NAC reduced the total number of white cells and the percentage of eosinophils in BALF. Moreover, it inhibited airway inflammation.

Conclusions:  The number of Clara cells and the production and secretion of CC16 were reduced in a murine model of allergen‐induced airway inflammation. Antioxidants can enhance the expression of CC16, which might be a mechanism by which they suppress airway inflammation.
Reproductive Biology of Curlleaf Mountain Mahogany, Cercocarpus ledifolius (Rosaceae): Self‐compatibility, Pollen Limitation, and Wind Pollination
Authors: RUSSELL SUSAN K. , SCHUPP EUGENE W. , TEPEDINO VINCENT J.
Published: March 2005

Abstract
In this study, we explore the reproductive biology of Cercocarpus ledifolius (Rosaceae), a species showing extremely limited recruitment throughout its range in the Intermountain West, USA. We examined (1) self‐compatibility, (2)the potential for wind pollination, (3) pollen limitation of seed production, and (4)loss of developing seeds. Through hand‐pollination experiments, we determined that C. ledifolius flowers are highly self‐compatible. Abundant seeds were produced from flowers pollinated with pollen from the same plant, and the level of seed production did not differ from control outcrossed treatments. Furthermore, we measured substantial airborne pollen loads within C. ledifolius stands, indicating transport of pollen via wind and a strong potential for wind pollination, despite apparent adaptations for insect pollination. Pollen did not limit seed production; branches on which all flowers were handpollinated with outcrossed pollen did not have greater seed production than control branches open only to natural pollination. Lastly, virtually all initiated seeds developed to maturity, indicating low seed abortion rates and minimal loss to pre‐dispersal seed predators. Natural levels of fruit production were at or greater than mean fruit production for woody perennials. In summary, we found no evidence that the quantity of pollen, the source of pollen (self vs. outcrossed), or developing seed loss is seriously limiting recruitment of this species.
Role of Temperature in Dormancy Break and/or Germination of Autumn‐maturing Achenes of Eight Perennial Asteraceae from Texas, U.S.A.
Authors: BASKIN CAROL C. , BASKIN JERRY M. , VAN AUKEN OSCAR W.
Published: March 2005

Abstract
Achenes of Aster ericoides, Baccharis neglecta, Brickellia dentata, Eupatorium havavense, Gymnosperma glutinosum, Helianthus maximilianii, Verbesina virginica and Viguiera dentata were collected at maturity in autumn in southcentral Texas and tested for germination over a range of thermoperiods (15/6, 20/10, 25/15, 30/15 and 35/20°C)simulating those in the habitat from September to May. Achenes of Aster, Baccharis, Brickellia, Eupatorium and Gymnosperma were nondormant, thus cold stratification did not change the range of thermoperiods over which they germinated. However, cold stratification increased the percentage of Brickellia achenes germinating at 15/6 and 20/10°C. Achenes of Helianthus, Verbesina and Viguiera were conditionally dormant at maturity, and cold stratification decreased the minimum thermoperiod for germination of Helianthus, Verbesina and Viguiera achenes to 15/6°C and increased the maximum thermoperiod for germination of Verbesina achenes to 35/20°C.Thus, achenes of Helianthus and Viguiera exhibited a type 2 germination response pattern during dormancy break and those of Verbesina a type 3. Germination percentages of Helianthus, Verbesina and Viguiera achenes increased during 6–8 wk of incubation at 20/10 and 15/60°C, which simulate habitat temperatures from November to February. Therefore, winter field temperatures are favorable for dormancy loss as well as for germination. If the soil is too dry for germination of conditionally‐dormant achenes in autumn, a reduction of the minimum temperature for germination during winter would allow them to germinate in midto late winter, several months before the onset of the high temperature and drought conditions of early summer.
Taxonomy and Floral Biology of Scleropogon (Eragrostideae: Gramineae)
Authors: ANTON ANA M. , CONNOR HENRY E. , ASTEGIAN MARTA E.
Published: March 2005

Abstract
Scleropogon brevifolius is a monotypic, disjunct, New World, colony‐forming, perennial grass. Its nomenclature is relatively uncluttered. Its floral biology has always been confusing in its detail.

Dioecism in S. brevifolius is expressed in sexually dimorphic inflorescences, and in adjusted floral sex ratios between male and female plants. At Uspallata in Precordilleran Argentina the primary sex ratio is met for female plants in the population (F/n=0.5), but male plants at 0.149 depart from expectation. Analysis of the remainder shows it to consist of monoecious variants among which andromonoecism (0.186) is the most significant. The contribution of ovules and pollen to the next generation by females, andromonoecids, and males is ca 80%—the balance is from very low frequency trimonoecious, monoecious, and hermaphrodite elements.

The projected pathway to dioecism is via monoecism, and the numerous intermediate sex forms in the population allow the identification of many positions on that route. In the Uspallata population strict monoecism itself is <1% but premonoecism is at high frequency—ca 32%.

Dioecism is still actively evolving on the male side, the early and characteristic fixation of male sterility genes having established the female element. Reasons for genetic tardiness in establishing complete control of female sterility are unknown. But the form of sexual expression displayed suggests a temporal aspect of evolution. The closest approximation in the grasses to the sex form diversity of S. brevifolius lies in New World Buchloe dactyloides which it matches in dimorphism, several sexual morphs, chamaechory, and in its colony form habit.
Molecular α‐taxonomy of Hymenasplenium obliquissimum Complex (Aspleniaceae) Based on rbcL Sequence Comparisons
Authors: MURAKAM NORIAKI , YOKOYAMA JUN , CHENG XIAO , IWASAKI HISAKO , IMAICHI RYOKO , IWATSUKI KUNIO
Published: March 2005

Abstract
Hymenasplenium obliquissimum (Hayata) Nakaike is easily distinguished from other members of Hymenasplenium by its peculiar thin (two‐cell thick) and translucent laminae with no air spaces, which are adapted to their subaquatic habitat. However, there also exist intermediate forms which are similar to H. obliquissimum in gross morphology but live in drier habitats, having thicker (3–4 cell layers) and opaque laminae with air spaces. The two different laminae forms sometimes grow together and create a complex in southwestern China and northern Thailand. In this work, we determined the rbcL sequences of 21 samples from the complex and conducted molecular phylogenetic analysis. Three major clades were detected; one of them was composed only of specimens with thin forms from various localities, supporting the assertion that species with the thin laminae type (H. obliquissimum) are a different biological unit from those with the thicker laminae type. Two clades were recognized as having the thicker laminae type, but we failed to find any morphological difference between them. In the present study, we found sequence variations of the rbcL gene even in a fern species complex which is morphologically hard to distinguish. Such molecular techniques are useful even for monographic works which try to delimit species, especially of morphologically similar taxa like ferns.
The Selection of Pollen and Seed Dispersal in Plants
Authors: WEBB COLIN J.
Published: March 2005

Abstract
Because plants are mostly sessile, dispersal of pollen and seeds during reproduction determines changes in gene frequencies within populations and plant distributions on a broader scale. Selection favours a mixture of local and distant dispersal and for nearly all plants this is achieved with a single type of dispersal structure because dispersal is relatively ineffective on average whatever the dispersal mode; this ineffectiveness probably accounts for the rarity of dimorphic dispersal structures. Empirical studies show that most dispersal is local, but far‐dispersal events, because of their potential to increase fitness though colonisation of unoccupied habitat patches, are probably what largely determines the selection of dispersal structures. The effectiveness of dispersal can be described in terms of distance, and the ability to reach favourable habitats. Effectiveness in achieving distance, a result of the interaction of the dispersal mode and agent with the environment, results in the typical leptokurtotic dispersal curve. There is no evidence that the shape of the dispersal curve itself is selected.
Size‐dependent Variation of Phenotypic Gender and Functional Gender of a Spring Ephemeral, Anemone debill's Fisch.
Authors: KUDO GAKU , MAEDA TOSHlHlKO
Published: March 2005

Abstract
The effect of plant size on phenotypic gender and functional gender was studied within a population of a hermaphroditic perennial herb, Anemone debilis, which had only one perfect flower on a plant. Seed‐set under natural conditions was 69–89%. and the selfing rate by autodeposition was 49% of maximum possible seed‐set. Phenotypic gender calculated from the stamen and ovule numbers changed with individual flower size measured by dry weight; large plants having larger flowers allocated more to female function (ovule number) than small plants. Matured seed number increased linearly with flower size, whereas estimated sired seed number indicated a saturating pattern. Functional gender calculated from the produced seed number and the estimated sired seed number changed with flower size, where large plants succeeded relatively better as mother plants and some small plants succeeded as pollen donors only. Thus. size‐dependent sex allocation between the male and female functions at a flowering stage seemed to reflect the paternal and maternal success for seed production.
Effect of Seasonal Temperature Changes on Germination Responses of Buried Seeds of Agalinis fasciculate (Scrophulariaceae), and a Comparison with 12 Other Summer Annuals Native to Eastern North America
Authors: BASKIN CAROL C. , BASKIN JERRY M. , CHESTER EDWARD W.
Published: March 2005

Abstract
Seeds of Agalinis fasciculata, a native eastern North American summer annual, were dormant at maturity inautumn and thus did not germinate in light or in darkness at 12/12 hdaily temperatures of 15/6,20/10, 25/15,30/15 and 35/20°C.Buried seeds exposed to natural temperature changes in Lexington, Kentucky (USA) for 53 months came out of dormancy in late autumn and winter and re‐entered it in late spring and early summer of each year. Non‐dormant seeds germinated to 60–100% in light at 20/10°C. Stratification at 5°C broke dormancy, and nondormant seeds entered dormancy during exposure to 25/15 or 30/15°C. Light was required for germination, but some seeds could be light‐stimulated during stratification. Seeds stratified in light had a broader temperature range for germination than those stratified in darkness and tested in light. Buried seeds of 11 of the 12 previously‐studied native eastern North American summer annuals exhibited seasonal changes intheir dormancy states. As buried seeds of the 12 species began to come out of dormancy during winter, they germinated only at high temperatures, but with additional stratification the minimum temperature for germination decreased, which is a Type 2 temperature response pattern. As seeds of A. fasciculata began to come out of dormancy during stratification, they germinated at an intermediate temperature (20/10°C), but with additional stratification the maximum temperature for germination increased and the minimum temperature decreased, which is a Type 3 pattern. This is the first report of a Type 3pattern in a summer annual and in the Scrophulariaceae. However, the ecological significance, if any, of Type 3 in A. fasciculata seeds is unknown and may reflect more about the past history of the species or its ancestors than it does about present‐day ecological adaptations to the habitat.
Population Biology of Faguscrenata Blume I. Demographic Genetic Differentiations of Lowland and Montane Populations in Toyama, Central Honshu, Japan
Authors: OHKAWA TOMOSHI , NAGAI YUKIO , MASUDA JUNZO , KITAMURA KEIKO , KAWANO SHOICHI
Published: March 2005

AbstractBased on demographic genetic differentiations, six isolated small lowland populations and one continuous large montane population of the Siebold's beech forests(Fagus crenata)in Toyama Prefecture, Honshu, Japan, were examined using isozymes as genetic markers. The results of within and among‐population genetic variabilities revealed that all six lowland populations, which are fragmented and isolated from each other at present, showed significantly lower percentages of polymorphic loci(P)and lower mean numbers of alleles per locus(A)than the montane population. Fluctuations in allele frequencies were observed in lowland populations. Alleles that were rare in the montane populationshowed unexpectedly higher frequencies in some lowland populations. The meanFSTvalue of the lowland populations (0.116) was significantly higher than that of the montane population in Tateyama (0.005)and several other populations analyzed. All these facts suggest that small isolated Siebold's beech populations remaining on the foothills in the lowlands of Toyama Prefecture have been exposed to climate shifts and strong human disturbances, which result in fragmentation and isolation of local populations. On the other hand, the large continuous montane population on Tateyama maintains a higher genetic variability, with genetic reshuffling within and among subpopulations. Spatial genetic localizations and the resulting changes in the size‐class structure in lowland populations were also discussed in relation to the demographic changes.
Molecular Systematics of the Genus Uvularia and Selected Liliales Based upon mat K and rbc L Gene Sequence Data
Authors: HAYASHI KAZUHIKO , YOSHIDA SEIJI , KATO HIDETOSHI , UTECH FREDERICK H. , WHIGHAM DENNIS F. , KAWANOI SHOICHI
Published: March 2005

Abstract
To elucidate the affinity and phylogeny of the endemic North American genus Uvularia, two chloroplast genes, matK and rbcL, were sequenced for all five species of the genus (Uvufaria floridana, U. grandifolia, U. perfoliata, U. puberula, and U. sessilifolia) and four selected members of the Liliales (Erythronium japonicum, Disporum sessile, Medeola virginiana, and Clintonia borealis). Sequence data of both matK and rbcL genes support an Uvularia which consist of two clades, section Oakesiella and section Uvularia. Though sessile‐leaved and associated with section Oakesiella, U. puberula exhibits several intermediate characteristics between the sections. However, the overall molecular results correspond to an earlier sub‐grouping based upon gross morphology, karyology and ecological life history traits. These two cpDNA genes, notably matK tree, proved to be informative in reaffirming relationships within Uvularia. Differentiation patterns among selected morphological, karyological and life history traits were also analyzed in comparison to the resulting molecular topologies.

In comparison to the selected outgroups, Disporum sessile proved to be closely related to Uvufaria in a narrowly defined Uvulariaceae ‐Uvulariea sensu Takhtajan (1997) or an expanded Colchicaceacae with a “uvularioid line”sensu Nordenstam (1998). The outgroup taxa, Erythronium, Medeola, and Clintonia, associate as a well supported lineage within a narrowly defined Liliaceae. Comment is also made on the multiple origins of berry fruits inthe Liliales.
Local adaptation in host use among marine invertebrates
Authors: Sotka Erik E.
Published: March 2005

The study of interactions between small invertebrates and their larger plant and animal hosts has a long tradition. One persistent theme within this literature is that spatially‐segregated populations of terrestrial and freshwater invertebrates commonly adapt to local hosts across their geographic ranges. Marine examples are rare, which leaves the impression that marine populations are less likely to adapt to locally abundant hosts and more likely to evolve generalized or phenotypically‐plastic strategies. Here, I review a short but growing list of marine invertebrates that appear to display local adaptation in host use. As expected, most of the marine examples are brooded animals with weak dispersal potential. However, some species with pelagically dispersed larvae have apparently adapted to local hosts. This surprising result is consistent with recent evidence that pelagically‐dispersed larvae are not always broadly dispersed, that strong selective pressures maintain local differences in host use, or both. The presence of host‐mediated adaptation in the sea alters predictions on how marine communities respond to disturbance, supports the notion that marine consumer‐prey interactions can coevolve, and indicates that hosts play fundamental roles in the differentiation and perhaps speciation of small marine invertebrates.
Hubbell's fundamental biodiversity parameter and the Simpson diversity index
Authors: He Fangliang , Hu Xin‐Sheng
Published: March 2005

Central to Hubbell's neutral theory of biodiversity is a universal, dimensionless fundamental biodiversity parameter that is the product of community size and speciation rate. One of the most important discoveries of Hubbell's theory is that the species‐abundance distribution and the species–area relationship of the neutral metacommunity is completely determined by this fundamental biodiversity parameter, although the diversity patterns of the local community are collectively determined by the biodiversity parameter and migration. Using the relative abundance of species and following the concept of heterozygosity of population genetics, here we developed an analytical relationship between this biodiversity parameter and the well‐known Simpson diversity index. This relationship helps bridge the evolutionary aspect of biodiversity to the ecological and statistical aspect of the diversity. The relationship between these two parameters suggests that diversity patterns of the metacommunity can also be equally described by the Simpson index. This relationship provides an alternative approach to interpret and estimate the fundamental biodiversity parameter for the metacommunity.
Low functional redundancy in coastal marine assemblages
Authors: Micheli Fiorenza , Halpern Benjamin S.
Published: March 2005

The relationship between species and functional diversity remains poorly understood for nearly all ecosystem types, yet determining this relationship is critically important for developing both a mechanistic understanding of community assembly and appropriate expectations and approaches to protecting and restoring biological communities. Here we use two distinct data sets, one from kelp forests in the Channel Islands, California, and one from a global synthesis of marine reserves, to directly test how variation in species diversity translates into changes in functional diversity. We find strong positive relationships between species and functional diversity, and increased functional diversity of fish assemblages coinciding with recovery of species diversity in marine reserves, independent of the method used for classifying species in functional groups. These results indicate that low levels of redundancy in functional species traits exist across a suite of marine systems, and that fishing tends to remove whole functional groups from coastal marine ecosystems.
Does chemical composition of individual Scots pine trees determine the biodiversity of their associated ground vegetation?
Authors: Iason Glenn R. , Lennon Jack J. , Pakeman Robin J. , Thoss Vera , Beaton Joan K. , Sim David A. , Elston David A.
Published: March 2005

Despite plant secondary metabolites being major determinants of species interactions and ecosystem processes, their role in the maintenance of biodiversity has received little attention. In order to investigate the relationship between chemical and biological diversity in a natural ecosystem, we considered the impact of chemical diversity in individual Scots pine trees (Pinus sylvestris) on species richness of associated ground vegetation. Scots pine trees show substantial genetically determined constitutive variation between individuals in concentrations of a group of secondary metabolites, the monoterpenes. When the monoterpenes of particular trees were assessed individually, there was no relationship with species richness of associated ground flora. However, the chemical diversity of monoterpenes of individual trees was significantly positively associated with the species richness of the ground vegetation beneath each tree, mainly the result of an effect among the non‐woody vascular plants. This correlation suggests that the chemical diversity of the ecosystem dominant species has an important role in shaping the biodiversity of the associated plant community. The extent and significance of this effect, and its underlying processes require further investigation.
The functional consequences of random vs. ordered species extinctions
Authors: Gross Kevin , Cardinale Bradley J.
Published: March 2005

Recent work suggests that the effect of extinction on ecosystem function depends on whether or not species have identical extinction risks. Here, we use a simple model of community dynamics to predict how the functional consequences of random and non‐random extinction may differ. The model suggests that when resource partitioning or facilitation structures communities, the functional consequences of non‐random extinction depend on the covariance between species traits and cumulative extinction risks, and the compensatory responses among survivors. Strong competition increases the difference between random and ordered extinctions, but mutualisms reduce the difference. When diversity affects function via a sampling effect, the difference between random and ordered extinction depends on the covariance between species traits and the change in the probability of being the competitive dominant caused by ordered extinction. These findings show how random assembly experiments can be combined with information about species traits to make qualitative predictions about the functional consequences of various extinction scenarios.
Evolution toward multi‐year periodicity in epidemics
Authors: Kamo Masashi , Sasaki Akira
Published: March 2005

We studied why many diseases has multi‐year period in their epidemiological dynamics, whereas a main source of the fluctuation is a seasonality with period of 1 year. Previous studies using a compartment model with seasonality in transmission rate succeed to generate a multi‐year epidemiological dynamics, when, in particular, the seasonal difference is large. However, these studies have focused on the dynamical consequence of seasonal forcing in epidemiological dynamics and an adaptation of pathogens in the seasonal environment has been neglected. In this paper, we describe our study of the evolution of pathogen's sensitivity to seasonality and show that a larger fluctuation in the transmission rate can be favored in the life history evolution of pathogens, suggesting that multi‐year periodicity may evolve by natural selection. Our result proposes a new aspect of the evolution of multi‐year epidemics.
Susceptibility of Italian agile frog populations to an emerging strain ofRanavirusparallels population genetic diversity
Authors: Pearman Peter B. , Garner Trenton W. J.
Published: March 2005

Western populations of the Italian agile frog (Rana latastei) experience widespread genetic depletion. Based on population genetic theory, molecular models of immunity and previous empirical studies, population genetic depletion predicts increased susceptibility of populations to emergent pathogens. We experimentally compared susceptibility ofR. latasteipopulations upon exposure to an emerging strain ofRanavirus, frog virus 3 (FV3), using six populations spanning the geographical range and range of population genetic diversity found in nature. Our findings confirm this prediction, suggesting that the loss of genetic diversity accompanying range expansion and population isolation is coincident with increased mortality risk from an emergent pathogen. Loss of heterozygosity and escape from selection imposed by immunologically cross‐reactive pathogens may potentially generate range‐wide variation in disease resistance.