Contamination of wheat, barley and maize seeds with toxigenic Fusarium species and their mycotoxins in Tunisia

Author(s):  
Ines Jedidi ◽  
Eva M Mateo ◽  
Patricia Marín ◽  
Misericordia Jiménez ◽  
Salem Said ◽  
...  

Abstract Background Fusarium is a worldwide distributed fungal genus. It includes different species pathogenic to cereals among others crops. Some of these species can also produce toxic compounds towards animals and humans. Objective In this work, occurrence of fumonisins B1+B2, zearalenone, type A trichothecenes (T-2 and HT-2 toxins) and type B trichothecenes (deoxynivalenol and nivalenol) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. Methods Mycotoxins analyses were performed by using gas chromatography for type B trichothecenes and high-performance liquid chromatography for other mycotoxins. Obtained results were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction (PCR). Results Fumonisins occurred in 20.83% of wheat, 40% of barley, and 57.14% of maize samples, at levels exceeding European limits and suggesting a risk in Tunisian cereals, especially maize. Zearalenone, deoxynivalenol, nivalenol and T-2+HT-2 toxins were detected at lower values in only wheat and barley samples. PCR protocols showed the predominance of F. verticillioides especially in maize, and occurrence of F. equiseti and F. graminearum in wheat and barley, and F. proliferatum in only 2 maize samples. A very consistent correlation was found between the detection of F. verticillioides and the contamination by fumonisins, as well as between the presence of F. graminearum and the contamination by zearalenone, deoxynivalenol and nivalenol in the analyzed cereals. Conclusions Consequently, the detection of Fusarium species with the current polymerase chain reaction assays strategy in wheat, barley and maize grains may be considered predictive of their potential mycotoxin risk in these matrices.

Author(s):  
G. W. Hacker ◽  
I. Zehbe ◽  
J. Hainfeld ◽  
A.-H. Graf ◽  
C. Hauser-Kronberger ◽  
...  

In situ hybridization (ISH) with biotin-labeled probes is increasingly used in histology, histopathology and molecular biology, to detect genetic nucleic acid sequences of interest, such as viruses, genetic alterations and peptide-/protein-encoding messenger RNA (mRNA). In situ polymerase chain reaction (PCR) (PCR in situ hybridization = PISH) and the new in situ self-sustained sequence replication-based amplification (3SR) method even allow the detection of single copies of DNA or RNA in cytological and histological material. However, there is a number of considerable problems with the in situ PCR methods available today: False positives due to mis-priming of DNA breakdown products contained in several types of cells causing non-specific incorporation of label in direct methods, and re-diffusion artefacts of amplicons into previously negative cells have been observed. To avoid these problems, super-sensitive ISH procedures can be used, and it is well known that the sensitivity and outcome of these methods partially depend on the detection system used.


2020 ◽  
Vol 48 (1) ◽  
pp. 62-72
Author(s):  
E. A. Ershova

Сalanoid copepods of the genus Pseudocalanus play an important role in the plankton communities of the Arctic and boreal seas, often dominating in numbers and constituting a significant proportion of the biomass of zooplankton. Despite their high presence and significance in the shelf plankton communities, species-specific studies of the biology of these are significantly hampered by extremely small morphological differences between them, especially at the juvenile stages, at which they are virtually indistinguishable. In this paper, we describe a new, routine and low-cost molecular method for identifying all Pseudocalanus species found in the Atlantic sector of the Arctic: the Arctic P. acuspes, P. minutus and the boreal P. moultoni and P. elongatus, and apply it to describe the relative distribution of these species in four locations of the Arctic and sub-Arctic. With this method, species-specific polymerase chain reaction (ssPCR), mass identification of individuals of any developmental stage, including nauplii, is possible. This method can serve as an excellent tool for studying the species-specific biology of this group, describing their life cycles, as well as monitoring changes in Arctic marine ecosystems under the influence of changing climate.


Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 4
Author(s):  
Oleg S. Alexandrov ◽  
Olga V. Razumova ◽  
Gennady I. Karlov

5S rDNA is organized as a cluster of tandemly repeated monomers that consist of the conservative 120 bp coding part and non-transcribed spacers (NTSs) with different lengths and sequences among different species. The polymorphism in the 5S rDNA NTSs of closely related species is interesting for phylogenetic and evolutional investigations, as well as for the development of molecular markers. In this study, the 5S rDNA NTSs were amplified with universal 5S1/5S2 primers in some species of the Elaeagnaceae Adans. family. The polymerase chain reaction (PCR) products of five Elaeagnus species had similar lengths near 310 bp and were different from Shepherdia canadensis (L.) Nutt. and Sh. argentea (Pusch.) Nutt. samples (260 bp and 215 bp, respectively). The PCR products were cloned and sequenced. An analysis of the sequences revealed that intraspecific levels of NTS identity are high (approximately 95–96%) and similar in the Elaeagnus L. species. In Sh. argentea, this level was slightly lower due to the differences in the poly-T region. Moreover, the intergeneric and intervarietal NTS identity levels were studied and compared. Significant differences between species (except E. multiflora Thunb. and E. umbellata Thunb.) and genera were found. Herein, a range of the NTS features is discussed. This study is another step in the investigation of the molecular evolution of Elaeagnaceae and may be useful for the development of species-specific DNA markers in this family.


Author(s):  
L. E. Laróvere ◽  
R. Dodelson de Kremer ◽  
L. H. J. Lambooy ◽  
R. A. De Abreu

Background: Thiopurine methyltransferase (TPMT) catalyses the S-methylation of 6-thiopurine drugs, which are commonly used in the treatment of autoimmune diseases, leukaemia and organ transplantation. TPMT activity is polymorphic as a result of gene mutations. Ethnic variations in phenotype and genotype have been identified in previous population studies, but no information was available within Latin-American populations. Aim: To establish the genetic polymorphism of TPMT in an Argentine population. Methods: TPMT enzymatic activity of 147 healthy Argentine subjects was measured using a high-performance liquid chromatography method. The genotyping assay for nine defective alleles (TPMT*2 - *8) was based on restriction fragment length polymorphism polymerase chain reaction and allele-specific polymerase chain reaction methods. Results: All subjects had detectable TPMT activity. Twelve individuals with low to intermediate activity were heterozygous for one of the mutant alleles: nine were TPMT*1/*3A, two TPMT*1/*2 and one TPMT*1/*4. All examined subjects with normal activity had wild-type genotype (TPMT*1/*1). Conclusion: Variant TPMT alleles were present in 8·2% of the examined subjects, which is in accordance with other studies. The frequency of TPMT*3A, TPMT*2 and TPMT*4 was 3·1%, 0·7% and 0·3%, respectively. TPMT*3A was the most prevalent allele, which is in accordance with results from Caucasian populations. This study provides the first analysis of TPMT activity and allele frequency distribution in Argentina, South America.


2014 ◽  
Vol 38 (1) ◽  
pp. 99-106
Author(s):  
Ihab G. M. AL-Shemmari

The aim of this study was to identify pasteurella multocida and their types by PCR in cattle’s and buffaloesi bagdad from March to August 2012 on 204 animals , including 102 cattle and 102 buffaloes at slaughter houses from Baghdad .Blood samples and nasal swaps were collected , before slaughtering and lung tissues of slaughtered animal , and from 54 clinically suspected cases of pasteurellosis , including 27 bovines ,and 27 buffaloes the samples taken included blood and nasal swabs . Pasteurellamultocida were isolated from 94 animals include 49 cattle 45 buffaloes. The typing of the isolates by multiplex PCR for genotyping Pasteuerllamultocida revealed 93 isolates of type B , 31 from cattle and 62 from buffaloes ,and 81 isolates of type A , 55 from cattle and 26 from buffaloes .


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