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1.
 The dynamics and abundance of nectar secretion as well as sugar productivity were studied in flowers of brown mustard (Brassica juncea) cv. Małopolska and white mustard (Sinapis alba) cv. Borowska. Moreover, floral nectaries were examined under LM and SEM. In both cultivars lateral and median pairs of nectaries secreted nectar. However, differences were found in morphology and activity of these pairs. The lateral nectaries produced more nectar than the median ones. Nectar secretion started at loose bud and peaked during anther dehiscence. Average amount of nectarsecreted by 100 flowers of cv. Małopolska and cv. Borowska were 119.9 mg and 134 mg. Mean concentration of nectar was 26.7% and 23.4%, respectively. One hundred flowers of cv. Małopolska and cv. Borowska secreted 28.4 mg and 24.9 mg of sugars in nectar. Estimated sugar productivity per 1 ha of crop was 65.5 kg and 71.2 kg, respectively. Received August 28, 2002; accepted November 2, 2002 Published online: June 2, 2003  相似文献   

2.
Individuals with inflammatory bowel disease (IBD), such as Crohn''s disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal cancer (CRC) over healthy individuals. This risk is proportional to the duration and extent of disease, with a cumulative incidence as high as 30% in individuals with longstanding UC with widespread colonic involvement.1 Colonic dysplasia in IBD and colitis associated cancer (CAC) are believed to develop as a result of repeated cycles of epithelial cell injury and repair while these cells are bathed in a chronic inflammatory cytokine milieu.2 While spontaneous and colitis-associated cancers share the quality of being adenocarcinomas, the sequence of underlying molecular events is believed to be different.3 This distinction argues the need for specific animal models of CAC.Several mouse models currently exist for the study of CAC. Dextran sulfate sodium (DSS), an agent with direct toxic effects on the colonic epithelium, can be administered in drinking water to mice in multiple cycles to create a chronic inflammatory state. With sufficient duration, some of these mice will develop tumors.4 Tumor development is hastened in this model if administered in a pro-carcinogenic setting. These include mice with genetic mutations in tumorigenesis pathways (APC, p53, Msh2), as well as mice pre-treated with genotoxic agents (azoxymethane [AOM], 1,2-dimethylhydrazine [DMH]).5 The combination of DSS with AOM as a model for colitis associated cancer has gained popularity for its reproducibility, potency, low price, and ease of use. Though they have a shared mechanism, AOM has been found to be more potent and stable in solution than DMH. While tumor development in other models generally requires several months, mice injected with AOM and subsequently treated with DSS develop adequate tumors in as little as 7-10 weeks.6, 7 Finally, AOM and DSS can be administered to mice of any genetic background (knock out, transgenic, etc.) without cross-breeding to a specific tumorigenic strain. Here, we demonstrate a protocol for inflammation-driven colonic tumorigenesis in mice utilizing a single injection of AOM followed by three seven-day cycles of DSS over a 10 week period. This model induces tumors with histological and molecular changes closely resembling those occurring in human CAC and provides a highly valuable model for the study of oncogenesis and chemoprevention in this disease.8  相似文献   

3.
Sarcophaga (Sarcorohdendorfia) gracilior (Chen, 1975) is documented from specimens collected in Hubei Province, China, using morphological characters and wing interference patterns (WIPs). The female of S. (S.) gracilior is described for the first time, the male is redescribed, and both sexes are photographed. The distribution of the species is updated.  相似文献   

4.
A thymidine kinase heterozygote was isolated from a diploid human lymphoblast line which forms colonies with high efficiency in microtiter dishes. We show that this cell line, called TK6, can be mutated from a tK+/? to TK?/? state by diverse mutagens, including ethyl methanesulfonate, butyl methanesulfonate, nitrosomethylurea, UV light, ICR-191, 4-nitroquinoline oxide, fluorodeoxyuridine, benzo[a]pyrene and aflatoxin B1. We report here the experiments required to demonstrate the applicability of this new line in quantitative assays of mutation in human cells.Mitotic recombination between the centromere and the tk locus could not be induced by either dimethylsulfoxide or phorbol-12-myristate-13-acetate.  相似文献   

5.
The FF domain from the human protein HYPA/FBP11 folds via a low-energy on-pathway intermediate (I). Elucidation of the structure of such folding intermediates and denatured states under conditions that favour folding are difficult tasks. Here, we investigated the millisecond time-scale equilibrium folding transition of the 71-residue four-helix bundle wild-type protein by (15)N, (13)C(alpha) and methyl(13)C Carr-Purcell-Meiboom-Gill (CPMG) NMR relaxation dispersion experiments and by (1)H/(2)H-exchange measurements. The relaxation data for the wild-type protein fitted a simple two-site exchange process between the folded state (F) and I. Destabilization of F in mutants A17G and Q19G allowed the detection of the unfolded state U by (15)N CPMG relaxation dispersion. The dispersion data for these mutants fitted a three-site exchange scheme, U<-->I<-->F, with I populated higher than U. The kinetics and thermodynamics of the folding reaction were obtained via temperature and urea-dependent relaxation dispersion experiments, along with structural information on I from backbone (15)N, (13)C(alpha) and side-chain methyl (13)C chemical shifts, with further information from protection factors for the backbone amide groups from (1)H/(2)H-exchange. Notably, helices H1-H3 are at least partially formed in I, while helix H4 is largely disordered. Chemical shift differences for the methyl (13)C nuclei suggest a paucity of stable, native-like hydrophobic interactions in I. These data are consistent with Phi-analysis of the rate-limiting transition state between I and F. The combination of relaxation dispersion and Phi data can elucidate whole experimental folding pathways.  相似文献   

6.
【目的】本研究旨在探讨DNA条形码对中国蛛缘蝽科(半翅目:缘蝽总科)物种界定的适用性。【方法】对中国蛛缘蝽科13属23种207个样本的线粒体COI基因DNA条形码序列进行扩增,并扩增稻缘蝽属Leptocorisa 3个物种的31条内转录间隔区1(ITS-1)序列作为辅助标记。使用MEGA 11软件计算种间和种内遗传距离(Kimura 2-parameter, K2P);采用邻接法(neighbor-joining, NJ)进行物种聚类分析;利用中介邻接网络算法构建单倍型网络图。【结果】基于线粒体COI DNA条形码序列得出测试的中国蛛缘蝽科所有23个种的种内平均K2P距离在2%以下,种间K2P距离在0.98%~23.98%之间(平均17.50%)。多数物种彼此能够被较好地分开,且支持率较高。其中,中稻缘蝽Leptocorisa chinensis和大稻缘蝽L. oratoria共享部分COI单倍型,造成COI条形码无法区分二者,可通过ITS-1序列在单倍型网络分析中将二者区分。【结论】本研究得出的中国蛛缘蝽科中绝大部分物种的DNA条形码数据分析结果与基于形态特征的分类单元一致。然而,对于其中亲缘关系极近的物种,单靠线粒体数据尤其是COI条形码序列无法进行准确界定,需引入其他DNA序列或其他类型数据进行区分。  相似文献   

7.
8.
Lethrus (Lethrus) schneideri Král & Hillert, sp. n. from Thrace, Greece, is described. The new species is morphologically most similar and probably closely related to Lethrus (Lethrus) apterus (Laxmann, 1770) and Lethrus (Lethrus) ares Král, Rejsek & Schneider, 2001. Diagnostic characters (shape of mandibles, ventral mandible processes, pronotum and parameres) are illustrated. Character matrix for separation of males of the Lethrus species closely related to Lethrus schneideri Král & Hillert, sp. n. and geographic ranges for all species studied are mapped.  相似文献   

9.
Protein ADP-ribosylation is a reversible post-translational modification, which alters protein activity, localization, interactome or stability, leading to perturbation of cell signaling. This review summarizes the emerging data indicating that host cell ADP-ribosylating enzymes, poly(ADP-ribose) polymerases (PARPs), influence the course of a bacterial infection, in parallel to ADP-ribosylating bacterial toxins. Host cell PARP targeting could be an efficient therapeutic approach to treat certain bacterial infections, possibly by repurposing the approved or clinical trial PARP inhibitors developed for cancer therapy.  相似文献   

10.
The type 1 inositol 1,4,5-trisphosphate receptor (InsP(3)R1) is a ubiquitous intracellular Ca(2+) release channel that is vital to intracellular Ca(2+) signaling. InsP(3)R1 is a proteolytic target of calpain, which cleaves the channel to form a 95-kDa carboxyl-terminal fragment that includes the transmembrane domains, which contain the ion pore. However, the functional consequences of calpain proteolysis on channel behavior and Ca(2+) homeostasis are unknown. In the present study we have identified a unique calpain cleavage site in InsP(3)R1 and utilized a recombinant truncated form of the channel (capn-InsP(3)R1) corresponding to the stable, carboxyl-terminal fragment to examine the functional consequences of channel proteolysis. Single-channel recordings of capn-InsP(3)R1 revealed InsP(3)-independent gating and high open probability (P(o)) under optimal cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) conditions. However, some [Ca(2+)](i) regulation of the cleaved channel remained, with a lower P(o) in suboptimal and inhibitory [Ca(2+)](i). Expression of capn-InsP(3)R1 in N2a cells reduced the Ca(2+) content of ionomycin-releasable intracellular stores and decreased endoplasmic reticulum Ca(2+) loading compared with control cells expressing full-length InsP(3)R1. Using a cleavage-specific antibody, we identified calpain-cleaved InsP(3)R1 in selectively vulnerable cerebellar Purkinje neurons after in vivo cardiac arrest. These findings indicate that calpain proteolysis of InsP(3)R1 generates a dysregulated channel that disrupts cellular Ca(2+) homeostasis. Furthermore, our results demonstrate that calpain cleaves InsP(3)R1 in a clinically relevant injury model, suggesting that Ca(2+) leak through the proteolyzed channel may act as a feed-forward mechanism to enhance cell death.  相似文献   

11.
A total of 301 adult hispine beetles of the genera Cephaloleia and Chelobasis were found in rolled leaves of plants of 17 species of Zingiberales (families Costaceae, Heliconiaceae, Maranthaceae, Musaceae, and Zingiberaceae) during a field study at La Gamba, Golfito region, Costa Rica. Of these beetles, Cephaloleia belti was recorded from 12 potential host plant species, C. distincta from 7, C. dilaticollis from 5, C., Chelobasis bicolor, C. championi, and C. histrionica from 3, Chelobasis perplexa and C. instabilis from 2, whereas C. trivittata from only one. Of the plant species, Heliconia latispatha had 7 beetle species in its leaf rolls, Calathea lutea had 5, H. imbricata and H. rostrata had 4, H. stricta and Musa paradisiaca had 3, H. wagneriana had 2, while on H. vaginalis, H. danielsiana, H. densiflora, H. longiflora, Calathea crotalifera, C. platystachya, Goeppertia lasiophylla, Alpinia purpurata, Costus pulverulentus and Costus barbatus, H. densiflora, H. vaginalis, and H. danielsana only hispines of one species were found.Cephaloleia belti occurred together with beetles of six other hispine species, whereas Cephaloleia trivittata never shared a leaf roll with another hispine species. The remaining beetle species aggregated with one to four other hispines. Adults of C. belti and C. championi were frequently seen, occasionally also with C. dilaticollis, C. histrionica, and Chelobasis perplexa, to co-occur with the carabid Calophaena ligata in the same leaf roll without any sign of interspecific aggression.A comparison of host choices and the phylogeny of the hispines and of their host plants revealed no signs that beetles used species level phylogenetic relationships within the Zingiberales to select food plants. Obviously, within this plant order, rolled-leaf hispines choose their plant hosts in a nearly opportunistic manner. Seemingly, they use differences among plants at higher taxonomic levels but within the Zingiberales, the availability of young – rolled – leaves might be the actual decisive factor.  相似文献   

12.
In the present paper the species belonging to the Neoserica (sensu lato) septemlamellata group, that included so far only four known species, are revised. Here we describe eleven new species originating mainly from Indochina and Southern China: N. daweishanica sp. n., N. gaoligongshanica sp. n., N. guangpingensis sp. n., N. igori sp. n., N. jiulongensis sp. n., N. plurilamellata sp. n., N. weishanica sp. n., N. yanzigouensis sp. n. (China) N. sapaensis sp. n. (China, Vietnam), N. bansongchana sp. n., N. takakuwai sp. n. (Laos). The lectotypes of Neoserica septemlamellata Brenske, 1898 and N. septemfoliata Moser, 1915 are designated. Keys to the species and species groups are given, the genitalia of all species and their habitus are illustrated and distribution maps are included.  相似文献   

13.
Copper(II) and nickel(II) ternary complexes of L-dopa and related compounds   总被引:1,自引:0,他引:1  
The stability constants of the mixed ligand complexes of L-dopa, L-tyrosine, L-phenylalanine, and dopamine with copper(II) and nickel(II) ions and with 2,2'-bipyridyl and 1,10-phenanthroline were determined pH-metrically at 25 degrees C and an ionic strength of 0.2 mol/dm3 (KCl). Spectral studies were made to establish the binding mode of the ambidentate L-dopa in the ternary complexes. In contrast with the aromatic (N,N) donor atoms, the (O,O) binding mode of L-dopa is particularly favored in its ternary systems with copper(II) and nickel(II); thus, even at physiological pH there is a very considerable formation of (O,O)-bound mixed ligand complexes containing a free amino acid side-chain. Numerous binary transition metal-L-dopa complexes and the ternary complexes formed with various B ligands have been evaluated from a coordination chemistry aspect, with regard to the possibility of their therapeutic application in the treatment of Parkinson disease.  相似文献   

14.
Differences in morphology among species are proximately caused by changes in the ontogeny of individuals. It is therefore of importance to analyse possible differences in growth parameters among closely related species in order to understand what parameters are most and least likely, respectively, to change in evolution. In this paper I analyse growth in two closely related sympatric species, namely Great tit, Parus major, and Blue tit, P. caeruleus. The former is considerably larger than the latter in all external traits. The growth rates of the two species were found to be very similar for all traits, thus excluding differences in growth rate as a potential cause of evolutionary size changes. Offset of growth occurred at relatively similar times in the two species, excluding this factor as a major cause of the final size differences. However, size differences at hatching were pronounced and remained so throughout ontogeny, pointing to initial size (egg size or hatching size) as the target of factors promoting change. Bivariate allometric relations of traits vs. body size (mass) were similar between the two species at all ontogenetic stages. There was a high correlation among traits especially at intermediate age stages (5 and 8 days), but these correlations became weaker at older age and approached the low pattern of integration found in adults. All this suggests the operation of a general growth factor affecting all parts of the phenotype simultaneously, which has its major influence at the time of maximal growth. If closely related species in general have highly similar growth patterns, strong evolutionary allometry as found in many avian taxa is to be expected.  相似文献   

15.
Stitham J  Arehart EJ  Gleim S  Douville K  MacKenzie T  Hwa J 《Gene》2007,396(1):180-187
The human prostacyclin receptor (hIP) has recently been recognized as an important seven transmembrane G-protein coupled receptor that plays critical roles in atheroprevention and cardioprotection. To date, four non-synonymous genetic variants have been identified, two of which occur at the same Arg amino acid position (R212H, R212C). This observation instigated further genetic screening for prostacyclin receptor variants on 1455 human genomic samples. A total of 31 distinct genetic variants were detected, with 6 (19%) involving Arg residues. Distinct differences in location and frequencies of genetic variants were noted between Caucasian, Asian, Hispanic and African Americans, with the most changes noted in the Asian cohort. From the sequencing results, three Arg-targeted changes at the same 212 position within the third cytoplasmic loop of the human prostacyclin (hIP) receptor were detected: 1) R212C (CGC-->TGC), 2) R212H (CGC-->CAC), and 3) R212R (CGC-->CGT). Three additional Arg codon variants (all exhibiting the same CGC to TGC change) were also detected, R77C, R215C, and R279C. Analysis (GPCR and SNP databases) of 200 other GPCRs, with recorded non-synonymous mutations, confirmed a high frequency of Arg-targeted missense mutations, particularly within the important cytoplasmic domain. Preferential nucleotide changes (at Arg codons), were observed involving cytosine (C) to thymine (T) (pyrimidine to pyrimidine), as well as guanine (G) to adenine (A) (purine to purine) (p<0.001, Pearson's goodness-of-fit test). Such targeting of Arg residues, leading to significant changes in coding amino acid size and/or charge, may have potentially-important structural and evolutionary implications on the hIP and GPCRs in general. In the case of the human prostacyclin receptor, such alterations may reduce the cardio-, vasculo-, and cytoprotective effects of prostacyclin.  相似文献   

16.
王昕  常岩林  赵卓  郭明申 《昆虫学报》2014,57(10):1162-1170
【目的】螽斯精子结构复杂,具有特征性的箭头状顶体,是研究昆虫精子形成的理想材料。为了研究螽斯精子形成过程中的动态变化机制,特别是细胞核的凝集机制和箭头状顶体的发生机制,本研究对优雅蝈螽Gampsocleis gratiosa精细胞和精子的细胞核进行了观察。【方法】选择发育良好的优雅蝈螽成虫精巢为研究材料,利用透射电镜技术、普通光学显微镜和荧光显微镜技术,制作光镜切片和电镜切片进行观察。【结果】根据其形态结构变化特征,将优雅蝈螽精子形成过程中的细胞核分为4个阶段:圆形核、叶形核、柱状核和成熟阶段。我们还通过常规HE染色,结合DNA特异性荧光探针DAPI,证明了圆形核时期,精细胞内具有两个明显的球状结构,一个为细胞核,另一个是原顶体;精子成熟阶段,精子尾部排出的细胞质微滴中含有DNA。【结论】优雅蝈螽精子形成过程中,精细胞的细胞核经历了显著的形态变化,精细胞核的形态变化与细胞骨架微管相关,细胞核塑形伴随着染色质的重组。本研究为进一步阐明直翅目昆虫精子形成的分子机制奠定了基础。  相似文献   

17.
Integrin αvβ3 is most likely the foremost modulator of angiogenesis among all known integrins. Recombinant disintegrin DisBa-01, originally obtained from snake venom glands, binds to αvβ3, thereby significantly inhibiting adhesion and generating in vivo anti-metastatic ability. However, its function in mediator production is not clear. Here, we observed that the mediators VEGF-A, IL-8, and TGF-β are not produced by human umbilical vein endothelial cells (HUVEC cell line) or monocyte/macrophage cells (SC cell line) when cells adhered to vitronectin. However, when exposed to DisBa-01, HUVECs produced higher levels of TGF-β, and SC cells produced higher levels of VEGF-A. Nonetheless, HUVECs also showed an enhancement of apoptosis after losing adherence when exposed to disintegrin, which is a characteristic of anoikis. We propose that disintegrin DisBa-01 could be used to modulate integrin αvβ3 functions.  相似文献   

18.

Background

Although tropical climate of Thailand is suitably endowed with biodiversity of insects, flies of medical importance is not well investigated. Using information from literature search, fly survey approach and specialist’s experience, we review database of Sarcophaga (Liosarcophaga) dux Thomson (Diptera: Sarcophagidae), one of the priorities flesh fly species of medical importance in Thailand.

Results

This review deals with morphology, bionomics and medical involvement. Important morphological characteristics of egg, larva, puparia and adult were highlighted with illustration and/or micrographs. Search pertaining to molecular analysis used for fly identification and developmental rate of larvae were included. Medical involvement of larvae was not only myiasis-producing agent in humans and animals, but associated with human death investigations.

Conclusions

This information will enable us to accurate identify this species and to emphasis the increase medically important scene in Thailand.  相似文献   

19.
ABSTRACT. Tympanic hearing organs (ears) are reported for several tiger beetle (Cicindelidae) species. The paired ears are positioned bilaterally on the first abdominal tergum and consist of cavities covered by thin tympana. When the beetle is not flying the elytra covers its ears and reduces their sensitivity to sound. However, when the beetle is flying, its exposed ears are capable of detecting ultrasonic pulses. Under a microscope, beetles with their elytra artificially raised contract their abdomens in response to ultrasound. Ultrasonic emissions directed toward flying beetles induce them immediately to fly downward and land, a response which probably aids escape from predators, particularly echolocating bats. Other possible uses for the ears are the avoidance of diurnal insect predators and intraspecific communication.  相似文献   

20.
Ying Tian  Guo-Dong Ren  Qiang Li 《ZooKeys》2014,(426):111-118
This paper deals with a species-group carniolica of the genus Nacerdes from China. This species-group has seven known species/subspecies in the world and two of them are known from China. Nacerdes (Xanthochroa) arcuata sp. n. is a new species belonging to carniolica group. The species were collected from Anhui (Eastern China, 30°02''17.37"N, 118°50''1.72"E). A key to the species of the species-group from China is given along with a distribution map.  相似文献   

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