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Comparative studies of floral ontogeny represent a growing field that promise to provide new insights on floral evolution.
Floral ontogenetic information has been used successfully in Leguminosae for re-examining phylogenetic relationships at different
levels. Using epi-illumination light microscopy, we present original ontogenetic data in Astragalus compactus, which was chosen because of its unusual arrangement of inflorescence and variable occurrence of bracteoles on flowers. Based
on our results, uncommon ontogeny of the inflorescence led to the arrangement of flowers in four different positions. Variation
was observed not only in the presence of bracteoles, but also in the order of sepal initiation in flowers of the same inflorescence.
Surprisingly, besides the widely stated unidirectional pattern, bidirectional, sequential and an atypical unreported order
were observed. High degree of overlapping between whorls and formation of two types of common primordia also were found. The
variable occurrence of bracteoles suggests that the species is in an intermediate state towards fully lacking of bracteoles.
We propose that the variability of the sequence of sepal initiation is possibly a consequence of the function of mechanical
forces generated by surrounding leaves. Relationships between mechanical force and auxin signalling are discussed. 相似文献
123.
Naderi N Ahmad-Molaei L Mazar-Atabaki A Ronaghi A Shirazi-zand Z Motiei-Langroudi SM Eslahkar S 《Neurochemical research》2012,37(2):279-287
The anticonvulsant activities of cannabinoid compounds have been shown in various models of seizure and epilepsy. At least,
part of antiseizure effects of cannabinoid compounds is mediated through calcium (Ca2+) channels. The L-type Ca2+ channels have been shown to be important in various epilepsy models. However, there is no data regarding the role of L-type
Ca2+ channels in protective action of cannabinoids on acute and chronic models of seizure. In this study, the effects of cannabinoid
compounds and L-type Ca2+ channels blockers, either alone or in combination were investigated using acute model of pentylenetetrazole (PTZ)-induced
seizure in mice and chronic model electrical kindling of amygdala in rats. Pretreatment of mice with both cannabinoid CB1
receptor agonist arachidonyl-2′-chloroethylamide (ACEA) and endocannabinoid degradating enzyme inhibitor cyclohexylcarbamic
acid 3′-carbamoyl-biphenyl-3-yl ester (URB597) produced a protective effect against PTZ-induced seizure. Administration of
various doses of the two L-type Ca2+ channel blockers verapamil and diltiazem did not alter PTZ-induced seizure threshold. However, co-administration of verapamil
and either ACEA or URB597 attenuated the protective effect of cannabinoid compounds against PTZ-induced seizure. Also, pretreatment
of mice with diltiazem blocked the anticonvulsant activity of both ACEA and URB597. Moreover, (R)-(+)-[2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate
(WIN55,212-2), the non-selective cannabinoid CB1 and CB2 receptor agonist showed anticonvulsant effect in amygdala-kindled
rats. However, co-administration of WIN55,212-2 and verapamil attenuated the protective properties of WIN55,212-2. Our results
showed that the anticonvulsant activity of cannabinoid compounds is mediated, at least in part, by L-type Ca2+ channels in these two models of convulsion and epilepsy. 相似文献
124.
Vahid Younesi Haleh Nikzamir Mehdi Yousefi Jalal Khoshnoodi Mohammd Arjmand Hodjatallah Rabbani Fazel Shokri 《Microbiology and immunology》2010,54(9):534-541
Viruses and other microorganisms express specific pathogen‐associated molecular patterns that are recognized by cell surface or endosome‐associated Toll‐like receptors (TLR). There are many examples of viruses that have developed strategies to modulate TLR signaling through the use of viral or cellular molecules. Epstein–Barr virus (EBV) has recently been found to display a complex interaction with TLR. The aim of this study was to asses the effect of EBV infection on proliferative capacity of TLR7/8 and 9 agonist and CD40 ligand (CD40L) in normal B lymphocytes. Our results demonstrate that EBV induces a significant inhibition in proliferative response to TLR7/8 (P < 0.004) and TLR9 (P < 0.000) agonists but not to CD40L stimulation in enriched human normal B lymphocytes. Similar inhibitory effect was also observed in B lymphocytes prestimulated with the TLR agonists, implying that the suppressive effect is not due to downregulation of TLR protein expression by EBV. EBV infection did not induce apoptosis and did not downregulate TLR7/8 mRNA expression in B lymphocytes. Our results suggest that EBV might be able to evade the immune system by modulation of the TLR signaling pathway. 相似文献
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Elham Davoudi-Dehaghani Ali Mohammad Foroughmand Babak Saffari Massoud Houshmand Hamid Galehdari Mehdi Shafa Shariat Panahi Majid Yavarian Mohammad Hossein Sanati Somayeh Torfi 《生物学前沿》2011,6(5):422-432
To investigate the genetic structure of human populations in the South-west region of Iran, mitochondrial first hypervariable
DNA sequences were obtained from 50 individuals representing three different ethnic groups from Khuzestan Province. Studied
groups were Shushtari Persians and Chahar Lang Bakhtiyaries from Indo-European-speaking populations and Bani Torof Arabs from
Semitic-speaking linguistic families. Genetic analysis of mtDNA data showed high similarity of Chahar Lang Bakhtiyaries with
other Iranian Indo-European-speaking populations while Shushtaries and Bani Torofs had a closer affinity with Semitic-speaking
groups rather than to other Iranian populations. The relationship of Chahar Lang Bakhtiyaries and Bani Torof Arabs with their
neighbor populations can be explained by linguistic and geographic proximity. Whereas, the greater similarity of Shushtari
Persians with West Asian Arabs is probably according to high gene flow between them. This article represents a preliminary
study of three major ethnic groups of South-west Iran which investigates the potential genetic substructure of the region. 相似文献
128.
Annexin C4 has been identified as a new member of fungal annexin family. In search of function, we have generated an annexin C4 disruptant strain of human pathogen, Aspergillus fumigatus. Detailed phenotypic analysis confirmed a non essential role of annexin C4 in the growth and sporulation of this pathogen. We applied a comparative proteomics strategy to understand the possible role of this protein in the fungus. The modification of respiratory chain proteins and stress response proteins suggests the occurrence of a mild oxidative stress in anxC4 disruptant strain. This may indicate a possible anti stress function of annexin C4 in A. fumigatus. 相似文献
129.
Application of remote sensing (RS) and geographical information system (GIS) techniques has been increased in natural sciences. In fact, it is inevitable applying of these techniques in vegetation studies due to the existence of some problems in traditional methods (e.g. sampling, calculation, analysis and so on). On this scope, scientists must have sufficient information about the efficiency of these techniques as a useful tool in their studies. This study aims to evaluate the IRS-P6 LISS III and Landsat ETM+ efficiency in plant groups’ identification. In order to this purpose, 143 training samples were collected from areas that showed homogenous composition of plant species in at least area of 3600 m2 (60 × 60 m). Coordinates of these training samples were recorded using a GPS device and transferred to a GIS database. Also, ENVI 4.2 package has used to process and analyze the satellites data. Several methods of processing such as; spectral separability, supervised classification and assessment of classification accuracy were used in order to gain a satisfy evaluation of the data efficiency. The results indicated that net farming of alfalfa and Juniperus polycarpus–Artemisia kopetdaghensisi community have the most separability on the satellite images (1.99 for Landsat and 2 for IRS). Against, the least separabilities on the Landsat data were between Ju. polycarpus–Onobrychis cornuta and Ju. polycarpus–Ar. kopetdaghensis communities (1.57) and between Ju. polycarpus–Ar. kopetdaghensis and Ju. polycarpus–Agropyron intermedium (1.53) on the IRS data. According to these results, it is concluded that the satellite data are somedeal able to identify plant groups when vegetation communities are sufficiently homogenous, abundant and spectrally and ecologically separable. 相似文献
130.
The comparative effects of salinity and drought on activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and polyphenol oxidase (PPO) and contents of protein, proline, hydrogen peroxide, malondialdehyde (MDA), and carotenoids were studied in calluses of Salicornia persica and Salicornia europaea. Calluses were cultured on Murashige and Skoog medium (MS medium) containing iso-osmotic concentrations of NaCl (100, 300, and 600 mM) and mannitol (200, 500, and 1000 mM). Proline content increased in calluses of both species under NaCl- and mannitol-induced stresses. Under both stresses, S. persica accumulated higher amounts of protein as compared to S. europaea. Under both stresses, protein content in S. persica decreased in comparison to control. Antioxidant enzyme activities showed different trends in the two Salicornia species under salt and drought stresses but were higher in S. europaea than in S. persica. Changes of hydrogen peroxide and MDA contents of calluses subjected to salt stress followed a pattern different from that observed under drought stress. MDA content showed similar changes to hydrogen peroxide content. Carotenoid content decreased in both species under both stresses. Overall, at the cellular level, S. europaea calluses were more tolerant to both NaCl- and mannitol-induced stresses than calluses of S. persica. 相似文献