986 resultados para REFORMATSKY-TYPE REACTION
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The purpose of this study was to test the hypothesis that skeletal muscle adaptations induced by long-term resistance training (RT) are associated with increased myogenic regulatory factors (MRF) and insulin-like growth factor-I (IGF-I) mRNA expression in rats skeletal muscle. Male Wistar rats were divided into 4 groups: 8-week control (C8), 8-week trained (T8), 12-week control (C12) and 12-week trained (T12). Trained rats were submitted to a progressive RT program (4 sets of 10-12 repetitions at 65-75% of the 1RM, 3 day/week), using a squat-training apparatus with electric stimulation. Muscle hypertrophy was determined by measurement of muscle fiber cross-sectional area (CSA) of the muscle fibers, and myogenin, MyoD and IGF-I mRNA expression were measured by RT-qPCR. A hypertrophic stabilization occurred between 8 and 12 weeks of RT (control-relative % area increase, T8: 29% vs. T12: 35%; p>0.05) and was accompanied by the stabilization of myogenin (control-relative % increase, T8: 44.8% vs. T12: 37.7%, p>0.05) and MyoD (control-relative % increase, T8: 22.9% vs. T12: 22.3%, p>0.05) mRNA expression and the return of IGF-I mRNA levels to the baseline (control-relative % increase, T8: 30.1% vs. T12: 1.5%, p<0.05). Moreover, there were significant positive correlations between the muscle fiber CSA and mRNA expression for MyoD (r=0.85, p=0.0001), myogenin (r=0.87, p=0.0001), and IGF-I (r=0.88, p=0.0001). The significant (p<0.05) increase in myogenin, MyoD and IGF-I mRNA expression after 8 weeks was not associated with changes in the fiber-type frequency. In addition, there was a type IIX/D-to-IIA fiber conversion at 12 weeks, even with the stabilization of MyoD and myogenin expression and the return of IGF-I levels to baseline. These results indicate a possible interaction between MRFs and IGF-I in the control of muscle hypertrophy during long-term RT and suggest that these factors are involved more in the regulation of muscle mass than in fiber-type conversion. © Georg Thieme Verlag KG Stuttgart · New York.
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In vitro-produced bovine embryos become infected after exposure to bovine Herpesvirus type 5 (BoHV-5), yet no changes in developmental rates, mitochondrial activity and inhibition of apoptosis are detected in comparison to unexposed embryos. Thus, the aim of the present study was to assess the transcription of mitochondria-mediated apoptosis genes using TaqMan real-time polymerase chain reaction. Transcripts of mcl-1, caspase-2, -3, Apaf-1 and Bax genes were measured after exposure to BoHV-5 in vitro. Mitochondrial dehydrogenase activity was evaluated by MIT test and compared between groups of exposed and unexposed embryos, at day 7 of development. The rate of oocyte maturation was assessed by the extrusion of the first polar body. In summary, BoHV-5 exposed embryos retained their viability, mitochondrial dehydrogenase activity and displayed up-regulation of transcription of survival mcl-1 gene and down-regulation of Bax transcription in relation to mitochondria-mediated pathway which might improve embryo viability. These findings demonstrate that BoHV-5 exposed embryos maintain their viability and mitochondrial dehydrogenase activity with no compromise of embryos produced in vitro. (c) 2013 Elsevier Ltd. All rights reserved.
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Background: Infectious diarrhea can be caused by bacteria, viruses, or protozoan organisms, or a combination of these. The identification of co-infections in dogs is important to determine the prognosis and to plan strategies for their treatment and prophylaxis. Although many pathogens have been individually detected with real-time polymerase chain reaction (PCR), a comprehensive panel of agents that cause diarrhea in privately owned dogs has not yet been established. The objective of this study was to use a real-time PCR diarrhea panel to survey the frequencies of pathogens and co-infections in owned dogs attended in a veterinary hospital with and without diarrhea, as well the frequency in different countries. Feces samples were tested for canine distemper virus, canine coronavirus, canine parvovirus type 2 (CPV-2), Clostridium perfringens alpha toxin (CPA), Cryptosporidium spp., Giardia spp., and Salmonella spp. using molecular techniques.Results: In total, 104 diarrheic and 43 control dogs that were presented consecutively at a major private veterinary hospital were included in the study. Overall, 71/104 (68.3%) dogs with diarrhea were positive for at least one pathogen: a single infection in 39/71 dogs (54.9%) and co-infections in 32/71 dogs (45.1%), including 21/32 dogs (65.6%) with dual, 5/32 (15.6%) with triple, and 6/32 (18.8%) with quadruple infections. In the control group, 13/43 (30.2%) dogs were positive, all with single infections only. The most prevalent pathogens in the diarrheic dogs were CPA (40/104 dogs, 38.5%), CPV-2 (36/104 dogs, 34.6%), and Giardia spp. (14/104 dogs, 13.5%). CPV-2 was the most prevalent pathogen in the dual co-infections, associated with CPA, Cryptosporidium spp., or Giardia spp. No statistical difference (P = 0.8374) was observed in the duration of diarrhea or the number of deaths (P = 0.5722) in the presence or absence of single or co-infections.Conclusions: Diarrheic dogs showed a higher prevalence of pathogen infections than the controls. Whereas the healthy dogs had only single infections, about half the diarrheic dogs had co-infections. Therefore, multiple pathogens should be investigated in dogs presenting with diarrhea. The effects of multiple pathogens on the disease outcomes remain unclear because the rate of death and the duration of diarrhea did not seem to be affected by these factors.
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This study was undertaken to assess the frequency of angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism in patients with type 2 diabetes mellitus. A total of 162 patients with type 2 diabetes and 160 individuals without this disease were analyzed. From the diabetes group, 81 patients with cardiovascular risk (according to American Diabetes Association parameters) were selected to form another subgroup. For polymorphism identification, two polymerase chain reactions were performed: one reaction to identify all genotypes and a second one to confirm the presence of the I allele. The observed genotype frequencies were as follows: diabetes group I/I (19.1%), I/D (52.5%), D/D (28.4%); control group I/I (12.5%), I/D (55.6%), D/D (31.9%); and diabetes with cardiovascular risk group I/I (16.0%), I/ D (59.3%), D/D (24.7%). No statistically significant difference was observed between the allelic and genotypic frequencies in the analyzed groups. Previous studies reported an association between the D allele and type 2 diabetes in Caucasian and East Asian populations. However, in mixed populations, such as those found in Brazil, such an association was not found. This fact does not discard the need for more studies on the frequencies of this polymorphism in the Brazilian population and the associations with risk factors, which can compromise the quality of life of diabetes patients
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Four new heterobimetallic metal carbonyls were synthesized by the reaction of [W(CO)4(bipy)] (1) with copper(I) compounds leading to species with the general formula [W(CO)4(bipy)(CuX)] (X = Cl, N3, ClO4, BF4) (2-5). The metal carbonyl compounds were characterized by elemental analysis, infrared and UV -visible electronic spectroscopy and thermogravimetric analysis. The IR data for 2-5 show carbonyl stretching band patterns similar to compound 1 ; ie they exhibit the same number of bands. The UV - vis results show a dissociation reaction generating the starting compound 1 and CuX as consequence of a weak interaction between 1 and CuX. Thermal decomposition mechanisms as well as the thermal stability are influenced by the CuX fragments. The thermal stability decreases in the order [W(CO)4(bipy)] > [W(CO)4(bipy)(CuCl)] > [W(CO)4(bipy) (CuBF4)]. The X-ray results show the formation of WO3, CuWO4, Cu2O and CuO as final decomposition products.
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The dimeric compound [Pd(dmba)(μ-Cl)]2 (1) (dmba = N,N-dimethylbenzylamine) reacts with KX, in methanol/acetone, affording the analogous dimeric pseudohalide-bridged species [Pd(dmba)(X)]2 [X = NCO(2), SCN(3), CN(4)]. The compounds were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR data for 2-4 showed bands typical of coordinated pseudohalide ligands indicating clearly the occurrence of the exchange reaction. Their thermal behavior was investigated and suggested that their thermal stability is influenced by the bridging ligand. The thermal stability decreased in the order [Pd(dmba)(μ-SCN)]2>[Pd(dmba)(μ-Cl)] 2>[Pd(dmba)(;u-NCO)]2>[Pd(dmba)(μ-CN)]2. The X-ray results showed the formation of PdO as final decomposition product. © 1999 Elsevier Science Ltd. All rights reserved.
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Summary: Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. Of the 27 ulnar nerves of leprosy patients, 18 with type 1 reaction (T1R) and 9 with type 2 reaction (T2R) were followed-up for 6 months before and after steroid treatment. Clinical characteristics of pain complaints and clinical function were assessed, as well as the presence of F- and A-waves of the ulnar nerve using nerve conduction studies. The clinical and the neurophysiologic findings were compared to note positive concordances (presence of NP and A-waves together) and negative concordances (absence of NP and A-waves together) before and after treatment. Both reactions presented a high frequency of A-waves (61.1% in T1R and 66.7% in T2R, P < 0.05) and prolonged F-waves (69.4% in T1R and 65.8% in T2R, P = 0.4). No concordances were seen between pain complaints and F-waves. However, significant concordances between NP and A-waves were observed, although restricted to the T2R group ([chi]2 = 5.65, P = 0.04). After treatment, there was a significant reduction in pain complaints, as well as the presence of F- and A-waves in both groups (P < 0.05 for all comparisons). In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.
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Objective: To study the activation of an inflammatory cascade through leukocyte mRNA expression of TLR2, TLR4, MyD88, and pro-inflammatory cytokines in individuals with childhood onset type 1 diabetes. Design and methods: Seventy-six type 1 diabetic patients and 100 normoglycemic subjects (NG) 6 to 20 years old were recruited. Type 1 diabetic patients (DM1) were considered to have good (DM1G) or poor (DM1P) glycemic control according to the values of glycated hemoglobin. TLR2, TLR4, MyD88, interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) mRNA expressions were measured in peripheral blood leukocytes (PBL) by real-time polymerase chain reaction (PCR). Urea, creatinine, albumin, and total protein serum levels were determined. Urinary albumin-to-creatinine ratio (ACR) was calculated. Results: DM1 and DM1P patients showed higher glycated hemoglobin (10 and 11%, respectively) and serum glucose concentrations (208 and 226 mg/ dL, respectively) compared to NG (Glycated hemoglobin: 7% and glucose: 76 mg/ dL) (p < 0.05). PBL mRNA expressions of TLR2, MyD88, IL-1 beta, IL-6, and TNF-alpha were higher in DM1 and TLR2, IL-1 beta, and IL-6 expressions were higher in DMP1 compared to NG (p < 0.05). In DM1, serum albumin and total protein were lower, while serum urea and ACR were higher in comparison to NG (p < 0.05). However, these differences compared to NG were more pronounced in DM1P, which included nine individuals with microalbuminuria. Conclusions: Increased mRNA expression of TLR2, MyD88, and pro-inflammatory cytokines in leukocytes of patients with childhood onset type 1 diabetes indicates the development of a TLR2-mediated pro-inflammatory process, which may also be associated with an early inflammatory process in the kidney and the occurrence of microalbuminuria.
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Transgenic Citrus sinensis (L.) Osb. plants, cvs. Valencia and Hamlin, expressing Citrus tristeza virus (CTV) derived sequences were obtained by genetic transformation. The gene constructs were pCTV-CP containing the 25 kDa major capsid protein gene (CTV-CP), pCTV-dsCP containing the same CTV-CP gene in an intron-spliced hairpin construct, and pCTV-CS containing a 559 nt conserved region of the CTV genome. The transgenic lines were identified by PCR and the transgene integration was confirmed by Southern blot. Transgene mRNA could be detected in most transgenic lines containing pCTV-CP or pCTV-CS transgene. The mRNA of pCTV-dsCP transgene was almost undetectable, with very light bands in most analyzed plants. The transgene transcription appears to be closely linked to the type of gene construct. The virus challenge assays reveals that all transgenic lines were infected. However, it was possible to identify propagated clones of transgenic plants of both cultivars studied with a low virus titer, with values similar to the non-inoculated plants (negative control). These results suggested that the transgenic plants present some level of resistance to virus replication. The higher number of clones with low virus titer and where mRNA could not be detected or was presented in a very light band was found for pCTV-dsCP-derived transgenic lines.
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The effects of small fractions of calcium (x = 0, 0.05, 0.1, 0.15, and 0.20) on the structure and the catalytic properties of La2-xCaxCuO4 peroviskites have been investigated. The samples have been synthesized using the co-precipitation method. Perovskite-type oxides were characterized by XRD, TPR, XPS, XANES, SEM, and TEM. Catalytic tests for the water gas shift reaction (WGSR) were carried out in a tubular reactor at 290 degrees C. All samples showed a well-defined perovskite structure with surface areas between 6 and 18 m(2) g(-1). The partial substitution of La by Ca enhanced the stability of the perovskites and increased their reduction temperature. All catalysts were actives for WGSR, and the best catalytic performance was obtained for the La1.85Ca0.15CuO4 catalyst, but the samples with 5 and 10% of Ca had the best TOF values for reaction. These results can be associated to promoter effect of calcium, the high surface area, and the reducible species Cu-0 and Cu1+. (C) 2011 Elsevier B.V. All rights reserved.
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Angiotensin II (Ang II), acting via the AT1 receptor, induces an increase in intracellular calcium [Ca(2+)]i that then interacts with calmodulin (CaM). The Ca(2+)/CaM complex directly or indirectly activates sodium hydrogen exchanger 1 (NHE1) and phosphorylates calmodulin kinase II (CaMKII), which then regulates sodium hydrogen exchanger 3 (NHE3) activity. In this study, we investigated the cellular signaling pathways responsible for Ang II-mediated regulation of NHE1 and NHE3 in Madin-Darby canine kidney (MDCK) cells. The NHE1- and NHE3-dependent pHi recovery rates were evaluated by fluorescence microscopy using the fluorescent probe BCECF/AM, messenger RNA was evaluated with the reverse transcription polymerase chain reaction (RT-PCR), and protein expression was evaluated by immunoblot. We demonstrated that treatment with Ang II (1pM or 1 nM) for 30 min induced, via the AT1 but not the AT2 receptor, an equal increase in NHE1 and NHE3 activity that was reduced by the specific inhibitors HOE 694 and S3226, respectively. Ang II (1 nM) did not change the total expression of NHE1, NHE3 or calmodulin, but it induced CaMKII, cRaf-1, Erk1/2 and p90(RSK) phosphorylation. The stimulatory effects of Ang II (1 nM) on NHE1 or NHE3 activity or protein abundance was reduced by ophiobolin-A (CaM inhibitor), KN93 (CaMKII inhibitor) or PD98059 (Mek inhibitor). These results indicate that after 30 min, Ang II treatment may activate G protein-dependent pathways, including the AT1/PLC/Ca(2+)/CaM pathway, which induces CaMKII phosphorylation to stimulate NHE3 and induces cRaf-1/Mek/Erk1/2/p90(RSK) activity to stimulate NHE1
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The humoral immune response is dependent on the formation of antibodies. Antibodies are produced by terminally differentiated B cells, plasma cells. Plasma cells are generated either directly from antigen challenged B cells, memory cells or from cells that have undergone the germinal center (GC) reaction. The GC is the main site for class switch, somatic hypermutation and generation of memory cells. Different factors, both internal and external, shape the outcome of the immune response. In this thesis, we have studied a few factors that influence the maturation of the humoral response. We have studied how age affects the response, and we show that responses against thymus dependent antigens (TD) are more affected than responses to thymus independent (TI) antigens, in concordance with the view that the T cell compartment is more affected by age than the B cell compartment. Furthermore, we demonstrate that priming early in life have a big influence on the immune response in the aged individual. Priming with a TI form of the carbohydrate dextran B512 (Dx) induces a reduction of IgG levels in later TD responses against Dx. We have evaluated possible mechanisms for this reduction. The reduction does not seem to be caused by clonal exhaustion or antibody mediated mechanisms. We also showed that the reduced TD response after TI priming can be induced against another molecule than Dx. With the hypothesis that TI antigens induce a plasma cell biased maturation of the responding B cells, we examined the presence of Blimp-1, a master regulator of plasma cell differentiation, in GCs induced by TD and TI antigen. Blimp-1 was found earlier in GCs induced by TI antigen and the staining intensity in these GCs was stronger than in TD antigen induced GCs, indicating that plasma cells might be continuously recruited from these GCs. B cells undergoing the GC reaction are thought to be under a strict selection pressure that removes cells with low affinity for the antigen and also cells that have acquired self-reactivity. We investigated the effect of apoptotic deficiencies on the accumulation of somatic mutations in GC B cells. In mice lacking the death receptor Fas, lpr mice, the frequency of mutations was increased but the pattern of the mutations did not differ from wild type mice. In contrast, mice over-expressing the anti-apoptotic protein Bcl-2, had a lowered frequency of mutations and the mutations introduced had other characteristics.
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The topics I came across during the period I spent as a Ph.D. student are mainly two. The first concerns new organocatalytic protocols for Mannich-type reactions mediated by Cinchona alkaloids derivatives (Scheme I, left); the second topic, instead, regards the study of a new approach towards the enantioselective total synthesis of Aspirochlorine, a potent gliotoxin that recent studies indicate as a highly selective and active agent against fungi (Scheme I, right). At the beginning of 2005 I had the chance to join the group of Prof. Alfredo Ricci at the Department of Organic Chemistry of the University of Bologna, starting my PhD studies. During the first period I started to study a new homogeneous organocatalytic aza-Henry reaction by means of Cinchona alkaloid derivatives as chiral base catalysts with good results. Soon after we introduced a new protocol which allowed the in situ synthesis of N-carbamoyl imines, scarcely stable, moisture sensitive compounds. For this purpose we used α-amido sulfones, bench stable white crystalline solids, as imine precursors (Scheme II). In particular we were able to obtain the aza-Henry adducts, by using chiral phase transfer catalysis, with a broad range of substituents as R-group and excellent results, unprecedented for Mannich-type transformations (Scheme II). With the optimised protocol in hand we have extended the methodology to the other Mannich-type reactions. We applied the new method to the Mannich, Strecker and Pudovik (hydrophosphonylation of imines) reactions with very good results in terms of enantioselections and yields, broadening the usefulness of this novel protocol. The Mannich reaction was certainly the most extensively studied work in this thesis (Scheme III). Initially we developed the reaction with α-amido sulfones as imine precursors and non-commercially available malonates with excellent results in terms of yields and enantioselections.3 In this particular case we recorded 1 mol% of catalyst loading, very low for organocatalytic processes. Then we thought to develop a new Mannich reaction by using simpler malonates, such as dimethyl malonate.4 With new optimised condition the reaction provided slightly lower enantioselections than the previous protocol, but the Mannich adducts were very versatile for the obtainment of β3-amino acids. Furthermore we performed the first addition of cyclic β-ketoester to α-amido sulfones obtaining the corresponding products in good yield with high level of diastereomeric and enantiomeric excess (Scheme III). Further studies were done about the Strecker reaction mediated by Cinchona alkaloid phase-transfer quaternary ammonium salt derivatives, using acetone cyanohydrin, a relatively harmless cyanide source (Scheme IV). The reaction proceeded very well providing the corresponding α-amino nitriles in good yields and enantiomeric excesses. Finally, we developed two new complementary methodologies for the hydrophosphonylation of imines (Scheme V). As a result of the low stability of the products derived from aromatic imines, we performed the reactions in mild homogeneous basic condition by using quinine as a chiral base catalyst giving the α-aryl-α-amido phosphonic acid esters as products (Scheme V, top).6 On the other hand, we performed the addition of dialkyl phosphite to aliphatic imines by using chiral Cinchona alkaloid phase transfer quaternary ammonium salt derivatives using our methodology based on α-amido sulfones (Scheme V, bottom). The results were good for both procedures covering a broad range of α-amino phosphonic acid ester. During the second year Ph.D. studies, I spent six months in the group of Prof. Steven V. Ley, at the Department of Chemistry of the University of Cambridge, in United Kingdom. During this fruitful period I have been involved in a project concerning the enantioselective synthesis of Aspirochlorine. We provided a new route for the synthesis of a key intermediate, reducing the number of steps and increasing the overall yield. Then we introduced a new enantioselective spirocyclisation for the synthesis of a chiral building block for the completion of the synthesis (Scheme VI).
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Heterocyclic compounds represent almost two-thirds of all the known organic compounds: they are widely distributed in nature and play a key role in a huge number of biologically important molecules including some of the most significant for human beings. A powerful tool for the synthesis of such compounds is the hetero Diels-Alder reaction (HDA), that involve a [4+2] cycloaddition reaction between heterodienes and suitable dienophiles. Among heterodienes to be used in such six-membered heterocyclic construction strategy, 3-trialkylsilyloxy-2-aza-1,3-dienes (Fig 1) has been demonstrated particularly attractive. In this thesis work, HDA reactions between 2-azadienes and carbonylic and/or olefinic dienophiles, are described. Moreover, substitution of conventional heating by the corresponding dielectric heating as been explored in the frame of Microwave-Assisted-Organic-Synthesis (MAOS) which constitutes an up-to-grade research field of great interest both from an academic and industrial point of view. Reaction of the azadiene 1 (Fig 1) will be described using as dienophiles carbonyl compounds as aldehyde and ketones. The six-membered adducts thus obtained (Scheme 1) have been elaborated to biologically active compounds like 1,3-aminols which constitutes the scaffold for a wide range of drugs (Prozac®, Duloxetine, Venlafaxine) with large applications in the treatment of severe diseases of nervous central system (NCS). Scheme 1 The reaction provides the formation of three new stereogenic centres (C-2; C-5; C-6). The diastereoselective outcome of these reactions has been deeply investigated by the use of various combination of achiral and chiral azadienes and aliphatic, aromatic or heteroaromatic aldehydes. The same approach, basically, has been used in the synthesis of piperidin-2-one scaffold substituting the carbonyl dienophile with an electron poor olefin. Scheme 2 As a matter of fact, this scaffold is present in a very large number of natural substances and, more interesting, is a required scaffold for an huge variety of biologically active compounds. Activated olefins bearing one or two sulfone groups, were choose as dienophiles both for the intrinsic characteristic flexibility of the “sulfone group” which may be easily removed or elaborated to more complex decorations of the heterocyclic ring, and for the electron poor property of this dienophiles which makes the resulting HDA reaction of the type “normal electron demand”. Synthesis of natural compounds like racemic (±)-Anabasine (alkaloid of Tobacco’s leaves) and (R)- and (S)-Conhydrine (alkaloid of Conium Maculatum’s seeds and leaves) and its congeners, are described (Fig 2).