bluuebunny/crossref_metadata_2025 huggingface dataset:
Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization
Authors: Jentschel Kerstin , Thiel Dorothee , Rehn Frank , Ludwig‐Müller Jutta
Published: December 2006

Plant hormones, including auxins, might be signals during the establishment of an arbuscular mycorrhizal (AM) symbiosis. Here, we report on the concentrations of three auxins native to nasturtium (Tropaeolum majus L.) during early AM development. Indole‐3‐acetic acid (IAA), indole‐3‐butyric acid (IBA), and phenylacetic acid (PAA) were previously identified as endogenous compounds in this species by full‐scan gas chromatography–mass spectrometry. All auxinic compounds were influenced by AM colonization but showed completely different patterns. At very early stage, free IAA and IBA were lower in infected than in control roots, whereas PAA concentration was higher in infected roots than in controls. At later stages, PAA was reduced in colonized roots, whereas, especially, IBA was increased in colonized roots compared with controls. Measurement of total auxins confirmed a complex regulation pattern for the three compounds. In hyphae of Glomus intraradices, none of the auxins was detectable. Biosynthesis of the three auxins was measured using heavy labeled isotopes as precursors in control and AM‐inoculated roots. While not much difference was found in the IAA labeling pattern between controls and AM‐inoculated roots at both time points, IBA synthesis was slightly higher in AM‐inoculated roots. Double labeling experiments showed that two distinct pathways, a tryptophan‐dependent and a tryptophan‐independent biosynthetic pathway contribute to the synthesis of IAA in T. majus roots. Because T. majus is difficult to genetically manipulate, we have used tobacco plants transformed with the auxin‐inducible promoter GH3 fused to the β‐glucuronidase (GUS) reporter gene to investigate whether AM structures would co‐localize to cells harboring the auxin‐inducible promoter. Although the GUS activity increased significantly in AM‐inoculated roots, there was no obvious correlation between GH3::GUS expression and fungal structures.
The binding of α‐amylase to starch plays a decisive role in the initiation of storage starch degradation in turions of Spirodela polyrhiza
Authors: Reimann Rezarta , Ziegler Paul , Appenroth Klaus‐J.
Published: December 2006

Degradation of reserve starch in turions, perennation organs of the duckweed Spirodela polyrhiza, is induced by continuous red light (cR). Irradiation of the turions with this light results in the autophosphorylation of starch‐associated glucan water dikinase (GWD). The ensuing phosphorylation of the starch by this enzyme was proposed to result in the enhanced association of starch‐degrading enzymes to the starch granules and in the initiation of starch breakdown. The present results confirm that the irradiation of dark‐adapted turions with cR results in phosphorylation of the starch, accompanying changes in the capacity of the granule starch to bind turion endogenous α‐amylase, as well as changes in the starch degradation level. All three effects show very similar dependence on the time of irradiation, suggesting that they may be linked. The α‐amylase is a plausible candidate for effecting starch breakdown initiation. However, the increased binding capacity of the starch granules for this enzyme is insufficient to account for the initiation of the starch breakdown as this capacity is already high prior to the irradiation. The decisive effect of cR irradiation on starch degradation may lie in enabling α‐amylase to gain access to otherwise sequestered starch granules or in activating α‐amylase bound to the granules.
Stability of lymphocytes and Epstein–Barr virus during red blood cell storage
Authors: Qu L. , Triulzi D. J , Rowe D. T. , Griffin D. L. , Donnenberg A. D.
Published: December 2006

Background  The Epstein–Barr virus (EBV) establishes and maintains latent infection in B lymphocytes of the healthy adults. Lymphocytes remain viable during red blood cell (RBC) storage. The effect of RBC storage on the stability of EBV‐infected B lymphocytes and EBV genome is not known.

Study Design and Methods  Eight randomly selected non‐leukoreduced AS‐5 RBC units were stored for 42 days under standard blood bank refrigerated at 1–6 °C. Cell count and EBV genomes in CD19+ B lymphocytes were measured in fresh products and weekly for 6 weeks. Total white blood cells (CD45+), T lymphocyte (CD3+), and B lymphocyte (CD19+) were quantified by a single platform flow cytometric assay. EBV genomes were quantified by real‐time polymerase chain reaction using DNA purified from CD19+ B cells.

Results  Viable white blood cell, T and B lymphocytes followed a biphasic decline curve during RBC storage consisting of a steep steady decline during the first 3 weeks followed by a plateau for the remainder of the storage. At the end of the RBC shelf‐life, 19% of the original T and B cells remained viable. EBV genomes per 105 CD19+ B lymphocytes remained constant during RBC storage. However, the total EBV genomes in the RBC units decline by more than 80% of their original value at the end of RBC storage due to loss of viable B lymphocytes.

Conclusions  The results indicate that lymphocytes and EBV latently infected B cells can survive the normal storage conditions for RBC.
Presence of Subepithelial Lymphoid Nodules in the Teat of Ewes
Authors: Mavrogianni V. S. , Cripps P. J. , Brooks H. , Taitzoglou I. A. , Fthenakis G. C.
Published: December 2006

A total of 87 clinically healthy ovine teats were examined bacteriologically (by scraping the mucosa) and histologically. Teats examined were those of lactating mammary glands with no bacteria isolated (n = 23); of mammary glands after cessation of lactation with no bacteria isolated (n = 25); of lactating mammary glands with bacteria isolated (n = 22); and of mammary glands after cessation of lactation with bacteria isolated (n = 17). The salient histological feature was subepithelial leucocytic infiltration. In teat cisterns, lymphocytes were the predominant cell type and in teat ducts, lymphocytes and neutrophils were seen in equal proportions. Subepithelial lymphoid nodules, some with germinal centres, were detected in 43 (49%) teats. The majority of lymphoid nodules was observed at the border between teat duct and teat cistern. Presence of bacteria was significantly associated with the presence of leucocytic activity (P < 0.001) and with the presence of lymphoid nodules (P = 0.032). We conclude that the presence of induced subepithelial lymphoid tissue at the border between teat duct and teat cistern appears to be important in protecting the mammary gland during the early stages of bacterial invasion. The findings call for further investigations into the lymphoid structures of the teat; these should elucidate the role and development of mammary mucosa‐associated lymphoid tissues and may lead to strategies for enhancing non‐specific defence mechanisms of the mammary gland.
Effect ofα‐Interferon andα‐Tocopherol in Reversing Hepatic Cirrhosis in Rats
Authors: Mathew T. C. , Abdeen S. , Dashti H. , Mathew E. , Al‐Bader A.
Published: December 2006

The aim of this study was to assess the effects ofα‐interferon andα‐tocopherol (vitamin E), or a combination of both, in reversing hepatic fibrosis following the induction of cirrhosis using thioacetamide by histological and biochemical analysis. Fifty male Wistar rats were used in this study. The animals were divided equally into five groups. Animals in group I were used as controls. The remaining animals (groups II–V) were provided with 0.5 g/L of thioacetamide in order to induce liver cirrhosis. Group II animals were used as the cirrhotic control. Animals of groups III, IV and V were givenα‐interferon,α‐tocopherol and interferon together withα‐tocopherol, respectively, for 30 days. After 30 days the animals were killed and following gross morphological examination of the liver, the hepatic tissues were processed for histological analysis and the serum was used for liver function tests. Morphological analysis showed a decrease in the number of nodules on the surface of the liver in both interferon‐ as well as vitamin E‐treated cirrhotic rats. Histopathological analysis showed that the abnormalities of the cirrhotic liver were partially reversed and liver function tests showed an overall improvement following treatment of animals of groups III, IV and V. Combination therapy using both interferon andα‐tocopherol did not have any substantial effect on the rats compared with that when they were given separately. These findings suggest thatα‐interferon andα‐tocopherol may have therapeutic value in reversing liver cirrhosis.
Intraovarian Localization of Growth Factors in Induced Cystic Ovaries in Rats
Authors: Ortega H. H. , Salvetti N. R. , Amable P. , Dallard B. E. , Baravalle C. , Barbeito C. G. , Gimeno E. J.
Published: December 2006

We hypothesized that the special hormonal environment present in animals with cystic ovarian disease (COD) interferes with cellular production of growth factors (GFs). The objective of the present study was to characterize the expression of insulin‐like growth factor (IGF)‐I, fibroblast growth factor (FGF)‐2 and vascular endothelial growth factor (VEGF) in induced COD using immunohistochemistry. We used an experimental model based on the exposure to constant light of adult rats during 15 weeks. We quantified the expression of GFs in cystic and normal ovaries by the Immunohistochemical Stained Area (IHCSA). In animals with COD, a significant reduction in the IHCSA of IGF‐I in the follicular fluid, theca and granulosa layers of cysts occurred; and an increase in the interstitial tissue with regard to the control group. We found moderate immunoreactivity of FGF‐2 in granulosa and theca layers of secondary and tertiary follicles and lower expression in the granulosa and theca interna layers of cystic follicles. Immunoexpression of VEGF was found in granulosa and theca cells of secondary and tertiary follicles. This study shows changes in the ovarian expression of IGF‐I, FGF‐2 and VEGF in induced COD. We can propose that an alteration in the control of the follicular dynamic, through the GFs, added to other features, could be involved in the ovarian cyst pathogenesis.
Distribution Patterns of Uterine Glands and Embryo Spacing in the Mouse
Authors: Hondo E. , Phichitrasilp T. , Kokubu K. , Kusakabe K. , Nakamuta N. , Oniki H. , Kiso Y.
Published: December 2006

To clarify the mechanism of implantation, relationship between positioning of the mouse embryo in the uterus and distribution of uterine glands along the long axis of the uterine horn was examined by three‐dimensional remodelling of the uterine endometrium. There were two unique regions in the endometrium. Uterine glands were distributed widely from mesometrial to anti‐mesometrial side in one region. It was localized from lateral to anti‐mesometrial side in another. These different regions were alternately aligned throughout the uterine horn. The number and position of embryos was consistent with that of the latter region. This study suggests that the type of distribution of uterine glands is closely related to the positioning of the embryo in mice.
A Histological Study of the Seminal Vesicle of the Armoured Catfish Corydoras aeneus
Authors: Franceschini‐Vicentini I. B. , Papa L. P. , Bombonato M. T. S. , Vicentini C. A. , Ribeiro K. , Orsi A. M.
Published: December 2006

Most species of Corydoras exhibited a reproductive behaviour called ‘T‐position’, and exhibited an accessory gland in the male genital tract, called the seminal vesicle. It appeared that both the structure and the composition of the fluid varied considerably between the species investigated. Consequently, different opinions were proposed regarding the possible role of seminal vesicle on this particular reproductive behaviour. Male adults of Corydoras aeneus were collected, anaesthetized, and samples of seminal vesicle were fixed in Bouin's solution. The sections were stained with haematoxylin‐eosin and periodic acid Schiff. The seminal vesicle showed a system of anastomosed secretory tubules, forming a vesicular collective network, which gave rise to the vesicular ducts. The latter fused with the testicular efferent ducts and formed the spermatic ducts. Considering this fusion, when the sperm cells reached the spermatic ducts, the fluid produced at the seminal vesicle covered them. Histochemical studies evidenced the presence of neutral and acid glycosaminoglycans in the seminal fluid. Considering the reproductive behaviour of C. aeneus, it is believed that the protection associated with the immobilization of the sperm cells assures the sperm integrity during the passage through female's intestine until fertilization.
Fine Structure of the Retinal Pigment Epithelium, Bruch's Membrane and Choriocapillaris in the Camel
Authors: Altunay H.
Published: December 2006

The morphology of the retinal pigment epithelium (RPE) and closely associated Bruch's membrane and choriocapillaris was investigated by light and transmission electron microscopy in the camel (Camelus dromedarius). The study showed that RPE is composed of a single layer of hexanocuboidal cells that were joined laterally by a series of apically located tight junctions. In addition, adjacent from internal side of cell membrane at the level of tight junctions, an undefined structure which resembled the myofibrillar organization of skeletal muscles in appearance was located. These cells displayed numerous short basal infoldings and abundant thin apical processes which enclosed the rod outer segments. The epithelial cell nuclei were large, vesicular and eccentrically located. Within the epithelial cells, smooth endoplasmic reticulum was very abundant, while rough endoplasmic reticulum was present only in small amounts. Polysomes were also numerous and the mitochondria often displayed a ring‐shaped structure. Lipofuscin granules were plentiful in all locations. Bruch's membrane (complexus basalis) was typically pentalaminate throughout the retina. The endothelium of the choriocapillaris facing Bruch's membrane was extremely thin and heavily fenestrated. These fenestrations displayed typical single‐layered diaphragm as noted in most species.
The Syrinx of the Male Mallard (Anas platyrhynchos): Special Anatomical Features
Authors: Frank T. , Probst A. , König H. E. , Walter I.
Published: December 2006

The aim of this study was to investigate the special anatomical and topographical features of the syrinx in male adult stock ducks (Anas platyrhynchos). The syrinx of the mallard is a tracheobronchial type, consisting of a tympanum, a pessulus, medial tympaniform membranes, interanular membranes, an interbronchial ligament (bronchidesmus), and bronchosyringeal cartilage semi‐rings. Using a frozen sagittal section, it was possible to document the syringeal valve at the right lateral side of the tympanum. In the male stock duck the pessulus was massive and showed a longish oval, transparent area ventrally. The middle part of the pessulus had a nose‐shaped process on its left side, on which the left medial tympaniform membrane originated. The left‐sided, pear‐shaped syringeal bulla was divided into a left major and right minor chamber by a double‐walled, semilunar and opaque septum, approximately 5–6 mm in height. The first left and right C‐shaped bronchosyringeal cartilage was more prominent than the other ones and showed partial ossification. In addition, the first left bronchosyringeal cartilage was obviously thicker than the right one. In conclusion, it can be stated that the syrinx in male adult mallards shows some notable specific anatomical features that might have an influence on vocalization. However, to understand the complex mechanism of vocalization in mallards, more investigations, especially obtained by sonography and endoscopy, will be needed.
Histological Organization of Collared Peccary (Tayassu tajacu) Lip
Authors: Teófilo T. S. , Silva A. F. , Fontenele‐Neto J. D.
Published: December 2006

Collared peccary (Tayassu tajacu) belongs to the Tayassuidae family that is characterized by a dorsal scent gland located in the middle of the hump. It can be found from south‐west United States to Argentina. It is a very well‐adapted animal that can survive different environments, having a varied diet. Very little morphological information of the animal is available, except that concerning the reproductive tract. This study describes the histological organization of the collared peccary lip. The lip marks the junction between the integument and digestive system. It is lined by skin on the outer surface and mucosa on the inner surface. Skin appendages such as hair follicles and glands are usually found on the outer surface. The collared peccary's lip shows, on the outer surface, simple and sinus hair follicles as well as sebaceous and apocrine sweat glands. No salivary gland is found on the inner surface, and deep in the connective tissue pacinian corpuscles can be found. The connective tissue is rich in collagen and elastic fibres. The collared peccary's lip may be used not only for food prehension but also functions as a sensitive structure giving tactile input to the central nervous system.
The External and Middle Ear of the Striped Dolphin Stenella coeruleoalba (Meyen 1833)
Authors: Sassu R. , Cozzi B.
Published: December 2006

The ear of cetaceans, and especially the middle ear, is very different from that of terrestrial mammals and shows specific adaptations to diving. Our research, performed on six Striped dolphins (Stenella coeruleoalba) stranded along the Italian coasts of the Mediterranean Sea, concentrated on the morphology of the external and middle ear of this species. We report the findings using a proper Veterinary Anatomical Nomenclature and describe the characteristics of the auditory meatus of the external ear and the presence and morphology of the erectile tissue in the middle ear. Our anatomical and histological data highlight the structure and possible functions of the corpus cavernosum located in the middle ear of the Striped dolphin, and suggest a possible role for this structure in relation to pressure regulation during diving. Many of our observations indicate the existence of an internal regulatory system able to prevent barotraumas by regulating pressure and volume inside the middle ear cavity.
A Light and Scanning Electron Microscopic Study of the Epididymis Active State of the Endemic Mexican Rodent Peromyscus winkelmanni (Carleton) (Rodentia: Muridae)
Authors: Lorenzana M. G. , López‐Wilchis R. , Gómez C. S. , Aranzabal M. C. U.
Published: December 2006

The macroscopic and microscopic anatomy of the epididymis of the sexually mature Peromyscus winkelmanni (Carleton) was examined using light and scanning electron microscopy. The epididymis was divided into three regions: caput, corpus and cauda. The epididymal duct was lined with columnar and cubic epithelium with stereocilia and covered by a muscular connective tissue sheath. Capillaries appear to penetrate directly into the epithelium from the underlying connective tissue in the initial segment. The epididymal epithelium presents four cell types: principal, basal, apical and clear cells. Based on morphological differences (height of epithelial cells, length of the stereocilia, luminal area, larger diameter and spermatic index), the epididymis of P. winkelmanni, presents seven zones. The stereocilia of the epididymal ducts of zones I, II, IV and V are thick and tall, while in zone III they are thin and short. The stereocilia in zone VI are thin, while in zone VII they are short but thick. The secretory products observed in the lumen of the epididymal ducts have vesicular, granular and fibrous form in the seven zones. This study contributes to an understanding of the morphofunctional features of the epididymis in sperm maturation in a species that shows seasonal reproductive activity.
The Effect of Fertilizer Type and Level of N Fertilization Before and After Grassland Renewal on N Leaching Losses
Authors: Seidel K. , Müller J. , Kayser M. , Isselstein J.
Published: December 2006

When grassland is ploughed and reseeded this results in an increased mineralization of organically bound nitrogen (N) in the soil. Greater amounts of nitrate in autumn are at risk of being leached during the winter half of the year. In two field experiments, nitrate leaching was measured over 2 years after reseeding of a 9‐year‐old grassland field in spring on a sandy soil in northwest Germany. During the experiments, major management factors that can influence the intensity of mineralization were varied: Type of fertilizer, mineral N fertilizer or organic manure, and the level of fertilization, 0, 160 or 320 kg N ha−1 a−1, before renewal of the grassland, and level of fertilization, 0, 160 or 320 kg N ha−1 a−1 in mineral form, after renewal of the grassland. The type of fertilization as well as the level of N fertilization before ploughing had no significant effect on the soil mineral nitrogen content (SMN) in autumn and N leaching in the year following the grassland renewal. N fertilizer level after sward renovation had a significant effect on the nitrate leaching losses in the two following years. Fertilization at a rate of 320 kg N ha−1 resulted in leaching losses of 7 and 61 kg N ha−1 in the first and second subsequent years, respectively. At fertilizer rates of 0 and 160 kg N ha−1 leaching losses were lower than 5 kg N ha−1. It is concluded that for mown grassland no restriction of the N fertilization before the renovation of the sward is necessary to reduce the nitrate leaching risk as long as the amount of N fertilized does not exceed the N‐uptake by the crop. Similarly, the N fertilization after the sward renewal does not bear a particular leaching risk.
Root‐mediated Allelopathic Interference of Nettle‐leaved Goosefoot (Chenopodium murale) on Wheat (Triticum aestivum)
Authors: Batish D. R. , Lavanya K. , Pal Singh H. , Kohli R. K.
Published: December 2006

A study was conducted to determine the potential and nature of root‐mediated allelopathic interference of Chenopodium murale on wheat. Early growth of wheat reduced significantly in agar medium where C. murale seedlings were previously growing as well as in rhizosphere soil of C. murale. The reduction in wheat growth was due to the presence of inhibitory metabolites released by roots of C. murale in the growth media. Even the soil incorporation of root residues also reduced the wheat growth in terms of seedling length and seedling dry weight. Only a partial amelioration in growth inhibition occurred upon charcoal supplementation or nitrogen fertilization in these amended soils. Root residues did not reduce the available nutrients in the soil, which was rather nutrient rich. These results indicated the definite role of allelopathy of C. murale roots in retarding wheat growth. Root amended soils contained significantly higher amount of phytotoxic phenolics as the putative allelochemicals, which were ferulic acid, vanillic acid, p‐coumaric acid and benzoic acid. The study concluded that C. murale roots and their exudates exerted allelopathic effects on wheat by releasing water‐soluble phenolic acids as putative allelochemicals in soil.
The Differences in Grain Weight and Quality Within a Rice (Oryza sativa L.) Panicle as Affected by Panicle Type and Source‐sink Relation
Authors: Wang F. , Chen S. , Cheng F. , Liu Y. , Zhang G.
Published: December 2006

The effects of panicle type and source‐sink relation on the variation in grain weight (GW) and quality within a panicle were investigated using four japonica (Oryza sativa L.) varieties differing in grain density and two source‐sink adjusting treatments. There were significant differences in GW and filling grain percentage (FGP) among superior and inferior grains for compact‐panicle varieties (Xiushui 994 and Xiushui 63), while not for loose‐panicle ones (Xiushui 11 and Chunjiang 15). The floret‐removal treatment significantly improved the development of inferior florets and reduced the differences in FGP and GW between superior and inferior grains for the compact‐panicle variety, while leaf‐deleting treatment reduced FGP and GW of both superior and inferior grains. For the loose‐panicle varieties, the two treatments had little effect. The difference in chalky grain percentage (CGP) and amylose content (AC) between the two kinds of florets was larger in compact‐panicle varieties than in loose‐panicle ones. Both floret‐removal and leaf‐deleting treatments caused the changes in CGP and AC of superior or inferior grains for compact‐panicle varieties, but not for loose‐panicle ones. The difference in starch content (SC) between superior and inferior grains was much larger for Xiushui 994 than for Xiushui 11, and the two varieties differed in the response of SC to the change of source‐sink relation. The differences in AGP‐glucose pyrophosphorylase (ADPG‐Ppase), starch branching enzyme (SBE) and soluble starch synthase (SSS) activities between the two kinds of grains were basically same for the two varieties, with superior being higher than inferior ones at early filling stage and smaller at later stage. In floret‐removal treatment, the activities of ADPG‐PPase, SSS, and SBE in superior grains of Xiushui 994 decreased at early filling stage and increased at middle or later stages. Meanwhile, the activities of SSS and SBE in both kinds of grains at early filling stage, and of ADPG‐PPase and granule‐bound starch synthase (GBSS) in inferior grains over the whole stage were increased. In leaf‐deleting treatment, the activities of ADPG‐PPase and SBE at early filling stage and GBSS at later filling stage were reduced in superior grains, while SSS activity at middle filling stage and SBE activity at later stage were increased.
Coexistence Between GM and Non‐GM Maize Crops – Tested in 2004 at the Field Scale Level (Erprobungsanbau 2004)
Authors: Weber W. E. , Bringezu T. , Broer I. , Eder J. , Holz F.
Published: December 2006

The objective of the study was to test the feasibility of coexistence between genetically modified (GM) and non‐GM maize under real‐life agronomical conditions. GM hybrid maize with the event MON810 (Bt maize) was drilled at 30 sites in fields surrounded by near isogenic conventional maize, although only 27 sites could be finally evaluated. Field sizes of Bt maize varied between 0.3 and 23 ha, and the flowering period of the Bt and conventional maize was synchronous. At some sites, different planting dates of GM and non‐GM maize or an earlier ripening conventional maize were tested in additional strips to obtain altered flowering and thereby reduce cross‐pollination. The overlapping of flowering periods was successfully avoided only at two sites where non‐GM maize was planted 25 or 28 days later. During harvest, samples were taken from the conventional maize in strips at distances of 0–10, 20–30, and 50–60 m to the Bt maize fields to assess the GM DNA content as a function of distance. Sampled materials included chaffed plant material intended for silage (18 sites), grains (eight sites), or crushed husks and cobs (one site). Wind effects were taken into account by sampling in all four compass directions. Quantitative PCR was used to detect the event specific MON810 DNA sequence in sampled materials. The analysis was conducted by two certified independent diagnostic testing companies selected in a pre‐test. Taking averages over all compass directions and the two laboratories no samples collected beyond 10 m had levels of GM above the threshold of 0.9 %. In conclusion, the data indicate that coexistence of GM and conventional maize is possible under real‐life large‐scale agronomical conditions. Levels of GM DNA in harvested grain resulting from outcrossing can be managed to levels below 0.9 % by simply planting 20 m of conventional maize as a pollen barrier between adjacent fields.
Morphological Traits above the Flag Leaf Node as Indicators of Drought Susceptibility Index in Durum Wheat
Authors: Villegas D. , García del Moral L. F. , Rharrabti Y. , Martos V. , Royo C.
Published: December 2006

Selection criteria for drought tolerance would be helpful tools for wheat breeding programmes. To assess the usefulness of some morphological traits above the flag leaf node as indicators of yield and the susceptibility index (SI) of Fischer and Maurer, 10 durum wheat genotypes were used in experiments conducted under two water regimes at two latitudes in Spain during 3 years. Morphological traits were measured at anthesis, and yield, yield components and quality traits were evaluated at ripening. Principal components analysis showed associations between morphological traits and yield, yield components and quality, most of them caused by differences between environments. Peduncle weight, spike weight and length and awn length were significantly related to SI within environments. Spike and peduncle weight were the traits more related to yield and SI in all the experiments together and in the rainfed sites, while in the irrigated sites spike length was better. The spike weight and length were negatively associated with SI, while peduncle weight was positively associated to SI. Genotype means across all experiments were associated with SI values. These morphological traits could be selection criteria in breeding programmes to obtain varieties with good yield stability. The genetic variability found suggests opportunity for selection.
Evaluation of ‘quick and dirty’ DNA extraction methods for marker‐assisted selection in rice (Oryza sativa L.)
Authors: Collard B. C. Y. , Das A. , Virk P. S. , Mackill D. J.
Published: December 2006

Six simple methods for extracting DNA from rice seedlings were evaluated for marker‐assisted selection (MAS). The assessment of each method was based on PCR amplification of SSR markers, DNA yield and purity, time and cost. Based on these criteria, two methods were selected as being superior to other methods. The best two methods included the standard method developed at the International Rice Research Institute (IRRI), which utilizes a sodium dodecyl sulfate extraction buffer followed by chloroform/isoamyl alcohol extraction and a previously published method using sodium hydroxide and Tris. These two methods produced nearly identical PCR amplification results. The sodium hydroxide method is considerably simpler, quicker and cheaper than the standard IRRI method, and may be particularly useful for many applications of MAS or high‐resolution mapping. This method was also adapted into an effective high throughput method utilizing 96‐well plates emphasizing its versatility.
ESSENTIAL OIL OF CROTON NEPETAEFOLIUS AND ITS MAIN CONSTITUENT, 1,8‐CINEOLE, BLOCK EXCITABILITY OF RAT SCIATIC NERVE IN VITRO
Authors: Lima‐Accioly PM , Lavor‐Porto PR , Cavalcante FS , Magalhães PJC , Lahlou S , Morais SM , Leal‐Cardoso JH
Published: December 2006

The effects of the essential oil of Croton nepetaefolius (EOCN) and its major constituent, 1,8‐cineole, on the compound action potential (CAP) of nerve were investigated.

Experiments were performed in sciatic nerves dissected from Wistar rats, mounted in a moist chamber and stimulated at a frequency of 0.2 Hz, with electric pulses of 100 µs duration at 20–40 V. Evoked CAP were displayed on an oscilloscope and recorded on a computer. The CAP control parameters were as follows: peak‐to‐peak amplitude 8.1 ± 0.6 mV (n = 15); conduction velocity 83.3 ± 4.2 m/s (n = 15); chronaxie 58.0 ± 6.8 msec (n = 6); and rheobase 2.8 ± 0.1 V (n = 6).

Lower concentrations of EOCN (100 and 300 µg/mL) and 1,8‐cineole (153 and 307 µg/mL; i.e. 1 and 2 mmol/L, respectively) had no significant effects on CAP control parameters throughout the entire recording period. However, at the end of 180 min exposure of the nerve to the drug, peak‐to‐peak amplitude was significantly (P < 0.05) reduced to 27.4 ± 6.7 and 1.7 ± 0.8% of control values by 500 and 1000 µg/mL EOCN, respectively (n = 6), and to 76.5 ± 4.4, 70.0 ± 3.9 and 14.8 ± 4.1% of control values by 614, 920 and 1227 µg/mL (i.e. 4, 6 and 8 mmol/L) 1,8‐cineole, respectively (n = 6). Regarding conduction velocity, at the end of the 180 min exposure period, this parameter was significantly reduced to 85.8 ± 7.3 and 48.7 ± 12.3% (n = 6) of control values by 500 and 1000 µg/mL EOCN, respectively, and to 86.4 ± 4.5 and 76.1 ± 5.2% (n = 6) by 920 and 1227 µg/mL 1,8‐cineole, respectively. Chronaxie and rheobase were significantly increased by the higher concentrations of both EOCN and 1,8‐cineole.

It is concluded that EOCN and its main constituent 1,8‐cineole block nerve excitability in a concentration‐dependent manner, an effect that was totally reversible with 1,8‐cineole but not with EOCN. This suggests that other constituents of EOCN, in addition to 1,8‐cineole, may contribute to the mediation of this effect of EOCN.
DIFFERENTIAL ROLES OF RYANODINE‐ AND THAPSIGARGIN‐SENSITIVE INTRACELLULAR Ca2+ STORES IN EXCITATION–CONTRACTION COUPLING IN SMOOTH MUSCLE OF GUINEA‐PIG TAENIA CAECI
Authors: Hishinuma Shigeru , Saito Masaki
Published: December 2006

To explore roles of intracellular Ca2+ stores in excitation–contraction coupling in smooth muscle, we examined the effects of ryanodine, a fixer of ryanodine receptor–Ca2+ channels to an open state, and thapsigargin, a selective inhibitor of the Ca2+ pump in the intracellular stores, on smooth muscle contraction in the presence and absence of extracellular Ca2+ in guinea‐pig taenia caeci.

In Ca2+‐free solution, contractions induced by 0.1 mmol/L carbachol and 0.1 mmol/L histamine were reduced to approximately 65% of control by either 1 µmol/L thapsigargin or 10 µmol/L ryanodine. In contrast, caffeine‐induced contraction was reduced to approximately 40% of control by ryanodine, but was not affected by thapsigargin.

In the presence of extracellular Ca2+, thapsigargin slowly induced a large and sustained contraction. In contrast, ryanodine did not induce an apparent contraction, but increased the sensitivity of contractile responses to receptor agonists (carbachol, AHR‐602 and histamine) or depolarizing high K+ with no changes in the maximal contraction.

These results suggest that there are pharmacological and physiological differences between ryanodine‐ and thapsigargin‐sensitive intracellular Ca2+ stores in excitation–contraction coupling in smooth muscle, which may be responsible for their differential effects on the Ca2+‐influx pathway.
ATTENUATION OF VENTRICULAR HYPERTROPHY AND FIBROSIS IN RATS BY PITAVASTATIN: POTENTIAL ROLE OF THE RhoA–EXTRACELLULAR SIGNAL‐REGULATED KINASE–SERUM RESPONSE FACTOR SIGNALLING PATHWAY
Authors: Saka Masako , Obata Koji , Ichihara Sahoko , Cheng Xian Wu , Kimata Hirotaka , Noda Akiko , Izawa Hideo , Nagata Kohzo , Yokota Mitsuhiro
Published: December 2006

Inhibitors of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase (statins) manifest pleiotropic effects that may contribute to their therapeutic efficacy. However, the mechanism of the beneficial action of statins on cardiac hypertrophy and fibrosis remains unclear. We have now investigated this action of pitavastatin in Dahl salt‐sensitive (DS) rats.

The DS rats progressively develop marked hypertension when fed a diet containing 8% NaCl from 7 weeks of age. These animals exhibited pronounced cardiac hypertrophy and fibrosis, as well as upregulation of fetal‐type cardiac gene expression at 12 weeks of age, compared with DS rats fed a diet containing 0.3% NaCl. The abundance of mRNAs for collagen types I and III, angiotensin‐converting enzyme, transforming growth factor‐β1 and connective tissue growth factor was also increased in the heart of rats on the high‐salt diet.

Treatment of rats on the high‐salt diet with a non‐antihypertensive dose of pitavastatin (0.3 or 1 mg/kg per day) from 7 to 12 weeks of age attenuated the development of cardiac hypertrophy and fibrosis, as well as inhibiting the upregulation of cardiac gene expression. Pitavastatin also blocked the translocation of RhoA to the membrane fraction of the left ventricle and RhoA activation, as well as the phosphorylation of the mitogen‐activated protein kinases extracellular signal‐regulated kinase (ERK)‐1 and ERK‐2 and an increase in the DNA binding activity of serum response factor (SRF) in the heart induced by the high‐salt diet.

These findings suggest that the effects of pitavastatin on load‐induced cardiac hypertrophy and fibrosis are independent of its cholesterol‐lowering action and may be mediated, at least in part, through inhibition of RhoA–ERK–SRF signalling.
REGULATION OF HEPATIC CHOLESTEROL METABOLISM IN CETP+/–/LDLr+/– MICE BY CHOLESTEROL FEEDING AND BY DRUGS (CHOLESTYRAMINE AND LOVASTATIN) THAT LOWER PLASMA CHOLESTEROL
Authors: Harada Lila M , Carrilho Alexandre JF , Oliveira Helena CF , Nakandakare Edna R , Quintão Eder CR
Published: December 2006

The hepatic mechanisms involved in the simultaneous regulation of plasma cholesterol concentration and cholesteryl ester transfer protein (CETP) activity were investigated by sharply modifying the hepatic rates of cholesterol synthesis. This was accomplished by cholestyramine, lovastatin and cholesterol feeding in human CETP transgenic mice cross‐bred with low‐density lipoprotein receptor (LDLr)‐knockout mice, generating CETP+/–/LDLr+/– mice, which present a plasma lipoprotein profile resembling that of humans.

Analyses of pooled data showed that the plasma CETP activity correlated positively with plasma total cholesterol concentration, hepatic CETP mRNA and the liver microsomal cholesterol content; a negative correlation was found between plasma CETP activity and the liver 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase and LDLr mRNA levels. These coordinated events represent an efficient control system that stabilizes the cell cholesterol content.

Nonetheless, not all cholesterol metabolism regulatory systems seem to fit into a coherent pattern of responses, suggesting that other unknown cellular mechanisms play roles depending on the type of pharmacological intervention.

For example, microsomal cholesterol content was not affected by cholestyramine, but was increased on cholesterol feeding (as predicted), and, surprisingly, on lovastatin treatment. Furthermore, although both plasma cholesterol‐lowering drugs increased CYP7A1 mRNA and had no effect on CYP27 mRNA, other metabolic components were differentially modified. Cholestyramine and lovastatin, respectively, did not modify and increased both HMG‐CoA and sterol responsive element binding protein 1c mRNA, did not modify and lowered liver X receptor α mRNA, lowered and increased ATP binding cassette A1 mRNA and lowered and did not modify scavenger receptor B1 mRNA.

That is, different to unabsorbed cholestyramine, lovastatin, as an absorbed plasma cholesterol‐lowering drug, may have modified the activity of other unknown genes that play roles in the interaction of CETP with the metabolism of hepatic cholesterol.
RENAL DENERVATION ATTENUATES LONG‐TERM HYPERTENSIVE EFFECTS OF ANGIOTENSIN II IN THE RAT
Authors: Hendel Michael D , Collister John P
Published: December 2006

It is well accepted that some of the long‐term effects of angiotensin (Ang) II are mediated via the central nervous system. Some of these actions that are mediated by the circumventricular organs and the baroreceptor reflex are thought to then alter sympathetic nervous system activity. In particular, there is some debate as to the role of renal nerves in the chronic effects of AngII. The aim of the present study was to assess the contribution of the renal nerves in a long‐term model of progressive AngII‐induced hypertension.

Male Sprague‐Dawley rats were subjected to either bilateral renal denervation (RDX; n = 7) or sham surgery (SHAM; n = 8). Rats were instrumented with radiotelemetric transducers and venous catheters for the measurement of blood pressure and AngII infusion, respectively. A 4.0% NaCl diet and distilled water were provided ad libitum. The first 3 days served as the control period (7 mL/day, 0.9% NaCl, i.v.). This was followed by an infusion of AngII for 16 days (10 ng/kg per min, i.v.) and a 3 day recovery period identical to control.

Baseline arterial pressure between RDX and SHAM rats did not differ. Following AngII treatment, the arterial pressure of SHAM rats increased more rapidly than that of RDX rats. By Day 10 of treatment, the mean arterial pressure was significantly different between groups, having increased to 166 ± 4 mmHg in SHAM rats and 135 ± 11 mmHg in RDX rats. This trend continued for the remainder of AngII treatment.

The present results indicate that the renal nerves are necessary for the full expression of AngII‐induced hypertension.
DIFFERENTIAL CONTROL OF CARDIAC AND SYMPATHETIC VASOMOTOR ACTIVITY FROM THE DORSOMEDIAL HYPOTHALAMUS
Authors: Horiuchi J , McDowall LM , Dampney RAL
Published: December 2006

The dorsomedial hypothalamus (DMH) plays a crucial role in mediating the cardiovascular responses to different stressors, including acute psychological stress and cold stress. Activation of neurons in the DMH evokes increases in arterial pressure and in the activity of sympathetic nerves innervating the heart, blood vessels and brown adipose tissue. The descending pathways from the DMH to the spinal sympathetic outflow include synapses with neurons in medullary nuclei and possibly other brain stem regions.

Recent studies from our and other laboratories have indicated that neurons in the rostral ventrolateral medulla (RVLM) and in the region of the raphe pallidus (RP) in the medulla are important components of the descending pathways that mediate the cardiovascular response to activation of the DMH. Neurons in the RP primarily mediate the sympathetic cardiac components of the DMH‐evoked response, whereas the RVLM neurons primarily mediate the sympathetic vasomotor component.

Activation of DMH neurons not only increases heart rate and sympathetic vasomotor activity, but also resets the baroreceptor reflex such that it remains effective, without any decrease in sensitivity, over a higher operating range of arterial pressure.

Activation of 5‐hydroxytryptamine 5‐HT1A receptors in the medulla oblongata leads to a selective suppression of cardiac and sympathetic vasomotor components of the DMH‐evoked response, but does not affect sympathetic reflex responses evoked from baroreceptors or chemoreceptors. Thus, central 5‐HT1A receptors modulate cardiovascular responses evoked from the DMH in a highly potent but selective fashion.
Seed dynamics of resprouting shrubs in grassy woodlands: Seed rain, predators and seed loss constrain recruitment potential
Authors: CAMPBELL MONICA L. , CLARKE PETER J.
Published: December 2006

Abstract  Measuring the fate of seeds between seed production and seedling establishment is critical in understanding mechanisms of recruitment limitation of plants. We examined seed fates to better understand the recruitment dynamics of four resprouting shrubs from two families (Fabaceae and Epacridaceae) in temperate grassy woodlands. We tested whether: (i) pre‐dispersal seed predation affected seed rain; (ii) post‐dispersal seed predation limited seed bank accumulation; (iii) the size of the seed bank was related to seed size; and (iv) viable seeds accumulated in the soil after seed rain. There was a distinct difference in seed production per plant between plant families with the legumes producing significantly more seeds per individual than the epacrids. Seed viability ranged from 43% to 81% and all viable had seed or fruit coat dormancy broken by heat or scarification. Pre‐dispersal predation by Lepidopteran larvae removed a large proportion of seed from the legume seed rain but not the epacrids. Four species of ants (Notoncus ectatomoides, Pheidole sp., Rhytidoponera tasmaniensis and Iridomyrmex purpureus) were major post‐dispersal seed removers. Overall, a greater percentage of Hardenbergia (38%) and Pultenaea (59%) seeds were removed than the fleshy fruits of Lissanthe (14%) or Melichrus (0%). Seed bank sizes were small (<15 seeds m−2) relative to the seed rain and no significant accumulation of seed in the soil was detected. Lack of accumulation was attributed to seed predation as seed decay was considered unlikely and no seed germination was observed in our study sites. Our study suggests that seed predation is a key factor contributing to seed‐limited recruitment in grassy woodland shrubs by reducing the number of seeds stored in the soil.
A year‐long plant‐pollinator network
Authors: BASILIO ALICIA M. , MEDAN DIEGO , TORRETTA JUAN P. , BARTOLONI NORBERTO J.
Published: December 2006

Abstract  In this work we analyse the pollination community in a South American forest known as ‘talar’. This is a vegetal woody community that inhabits fossil coastal banks characterized by seasonal temperate weather and calcareous soil, at the coast of the Río de la Plata, in the province of Buenos Aires, Argentina. We obtained data of the interactions between anthophylous insects and entomophylous flowering plants over an extensive period of time. We showed that pollination system parameters, such as partners’ identity, system size, and connectance, fluctuated among months, when sampled year‐long. Maximal network size occurred in early spring and early autumn, when both the number of mutualistic species and the number of interactions peaked, and this was also when network asymmetry was higher than average. Monthly connectance of the plant‐flower visitor matrix decreased to its lowest values at these peaks. Available data suggest that cumulative traditional connectance (i.e. the connectance calculated as the whole number of interactions registered in the community divided by the full size system) underestimates actual connectance values by a factor of c. 3 ×. Monthly values of connectance decreased exponentially as system size increased, and the distribution of interactions per species followed power‐law regimes for animals, and truncated power‐law regimes for plants, in accordance with patterns previously deduced from among‐network cumulative communities studies. We think that either within or and among pollination networks, systems that are organized as power‐law regimes may be a basic property of these webs, and provide examples of the fact. Both seasonal changes and interactions between mutualists like competition, and some degree of facilitation, may be very important to understand the performance of the system as a whole, and the role and importance of different species in the community. We suggest that communities of plant – pollinators that exhibit extended activity, such as temperate or tropical seasonal ones, should be studied through consecutive plant‐pollinator webs rather than cumulative ones. The partition of the system into smaller serial parts allows us to obtain outstanding information of every short period. This information is flattened by the average effect when we considered the combined analysis of the whole data.
Mass loss and nutrient release from decomposing evergreen and deciduous Nothofagus litters from the Chilean Andes
Authors: DECKER KELLY L. M. , BOERNER RALPH E. J.
Published: December 2006

Abstract  Leaf litter decomposition experiments were conducted on two deciduous (Nothofagus obliqua (roble)) and Nothofagus pumilio (lenga)) and one evergreen (Nothofagus dombeyi) Nothofagus (Nothofagaceae) species from a single Chilean forest in order to understand how congeneric trees with differing leaf lifespans impact the soil in which they grow. Single‐species litter samples were decomposed in a mixed hardwood forest in Ohio and in a deciduous‐evergreen Nothofagus forest in Chile. In the Ohio forest, the two deciduous species’ litters decomposed at k ≈ 1.00 per year and the evergreen at k ≈ 0.75 per year. In Chile k ranged from k ≈ 0.06 (N. obliqua) to k ≈ 0.23 (N. pumilio) per year. In both experiments, N and P were released faster from the deciduous litters than from evergreen litter. In Ohio, evergreen litter immobilized more N and P for a longer time period than did deciduous litter. As N. dombeyi stands tend to have lower available soil N and P in this particular mixed Nothofagus forest, the increased time of N and P immobilization by N. dombeyi litter suggests a feedback role of the tree itself in perpetuating low N and P soil conditions.