scholarly journals Differentiation of Taxonomically Closely Related Species of the Genus Acinetobacter Using Raman Spectroscopy and Chemometrics

Molecules ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 168 ◽  
Author(s):  
A. Margarida Teixeira ◽  
Alexandr Nemec ◽  
Clara Sousa

In recent years, several efforts have been made to develop quick and low cost bacterial identification methods. Genotypic methods, despite their accuracy, are laborious and time consuming, leaving spectroscopic methods as a potential alternative. Mass and infrared spectroscopy are among the most reconnoitered techniques for this purpose, with Raman having been practically unexplored. Some species of the bacterial genus Acinetobacter are recognized as etiological agents of nosocomial infections associated with high rates of mortality and morbidity, which makes their accurate identification important. The goal of this study was to assess the ability of Raman spectroscopy to discriminate between 16 Acinetobacter species belonging to two phylogroups containing taxonomically closely related species, that is, the Acinetobacter baumannii-Acinetobacter calcoaceticus complex (six species) and haemolytic clade (10 species). Bacterial spectra were acquired without the need for any sample pre-treatment and were further analyzed with multivariate data analysis, namely partial least squares discriminant analysis (PLSDA). Species discrimination was achieved through a series of sequential PLSDA models, with the percentage of correct species assignments ranging from 72.1% to 98.7%. The obtained results suggest that Raman spectroscopy is a promising alternative for identification of Acinetobacter species.

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Congzhao Fan ◽  
Xiaojin Li ◽  
Jun Zhu ◽  
Jingyuan Song ◽  
Hui Yao

The medicinal plantFerulahas been widely used in Asian medicine, especially in Uyghur medicine in Xinjiang, China. Given that various substitutes and closely related species have similar morphological characteristics,Ferulais difficult to distinguish based on morphology alone, thereby causing confusion and threatening the safe use ofFerula. In this study, internal transcribed spacer 2 (ITS2) sequences were analyzed and assessed for the accurate identification of two salableFerulaspecies (Ferula sinkiangensisandFerula fukangensis) and eight substitutes or closely related species. Results showed that the sequence length of ITS2 ranged from 451 bp to 45 bp, whereas guanine and cytosine contents (GC) were from 53.6% to 56.2%. A total of 77 variation sites were detected, including 63 base mutations and 14 insertion/deletion mutations. The ITS2 sequence correctly identified 100% of the samples at the species level using the basic local alignment search tool 1 and nearest-distance method. Furthermore, neighbor-joining tree successfully identified the genuine plantsF. sinkiangensisandF. fukangensisfrom their succedaneum and closely related species. These results indicated that ITS2 sequence could be used as a valuable barcode to distinguish Uyghur medicineFerulafrom counterfeits and closely related species. This study may broaden DNA barcoding application in the Uyghur medicinal plant field.


2021 ◽  
Vol 3 (2) ◽  
pp. 260-272
Author(s):  
Mukesh Thakar ◽  
Tina Sharma

Disorganized and chaotic collection of the Euphorbia plant species from the wild is one of the major reasons for its endangered status. According to CITES, the trade in Euphorbia royleana species is prohibited under Appendix II. However, the trade continues unabated as current identification methods do not discriminate between closely related species.  In the present study, a DNA barcoding method has been used to establish inter- and intra-specific divergences of both matK and rbcL regions by using pairwise genetic distance measurement methods for evaluating the maximum barcoding gap. The matk and rbcL yielded a 100% amplification and sequencing success rate to distinguish closely related species of Euphorbia royleana unambiguously. The matk and rbcL showed average interspecific genetic distance divergence values of 0.031and 0.015, respectively. The maximum number of species-specific SNPs was observed in matK sequences at seven consecutive sites, which could distinguish Euphorbia royleana from closely related species.  The best candidate barcoding region to identify Euphorbia royleana was found to be matK with a single-locus barcoding approach. Furthermore, the species discrimination method was developed with the help of species-specific SNPs derived from the matK barcoding region to accurately authenticate Euphorbia royleana, and it provided 100% species resolution


2020 ◽  
Vol 9 (3) ◽  
pp. 160-170
Author(s):  
Thumadath P.A. Krishna ◽  
Maharajan Theivanayagam ◽  
Gurusunathan V. Roch ◽  
Veeramuthu Duraipandiyan ◽  
Savarimuthu Ignacimuthu

Finger millet is a superior staple food for human beings. Microsatellite or Simple Sequence Repeat (SSR) marker is a powerful tool for genetic mapping, diversity analysis and plant breeding. In finger millet, microsatellites show a higher level of polymorphism than other molecular marker systems. The identification and development of microsatellite markers are extremely expensive and time-consuming. Only less than 50% of SSR markers have been developed from microsatellite sequences for finger millet. Therefore, it is important to transfer SSR markers developed for related species/genus to finger millet. Cross-genome transferability is the easiest and cheapest method to develop SSR markers. Many comparative mapping studies using microsatellite markers clearly revealed the presence of synteny within the genomes of closely related species/ genus. Sufficient homology exists among several crop plant genomes in the sequences flanking the SSR loci. Thus, the SSR markers are beneficial to amplify the target regions in the finger millet genome. Many SSR markers were used for the analysis of cross-genome amplification in various plants such as Setaria italica, Pennisetum glaucum, Oryza sativa, Triticum aestivum, Zea mays and Hordeum vulgare. However, there is very little information available about cross-genome amplification of these markers in finger millet. The only limited report is available for the utilization of cross-genome amplified microsatellite markers in genetic analysis, gene mapping and other applications in finger millet. This review highlights the importance and implication of microsatellite markers such as genomic SSR (gSSR) and Expressed Sequence Tag (EST)-SSR in cross-genome analysis in finger millet. Nowadays, crop improvement has been one of the major priority areas of research in agriculture. The genome assisted breeding and genetic engineering plays a very crucial role in enhancing crop productivity. The rapid advance in molecular marker technology is helpful for crop improvement. Therefore, this review will be very helpful to the researchers for understanding the importance and implication of SSR markers in closely related species.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 789-796 ◽  
Author(s):  
Kyoichi Sawamura ◽  
John Roote ◽  
Chung-I Wu ◽  
Masa-Toshi Yamamoto

Abstract Recent genetic analyses of closely related species of Drosophila have indicated that hybrid male sterility is the consequence of highly complex synergistic effects among multiple genes, both conspecific and heterospecific. On the contrary, much evidence suggests the presence of major genes causing hybrid female sterility and inviability in the less-related species, D. melanogaster and D. simulans. Does this contrast reflect the genetic distance between species? Or, generally, is the genetic basis of hybrid male sterility more complex than that of hybrid female sterility and inviability? To clarify this point, the D. simulans introgression of the cytological region 34D-36A to the D. melanogaster genome, which causes recessive male sterility, was dissected by recombination, deficiency, and complementation mapping. The 450-kb region between two genes, Suppressor of Hairless and snail, exhibited a strong effect on the sterility. Males are (semi-)sterile if this region of the introgression is made homozygous or hemizygous. But no genes in the region singly cause the sterility; this region has at least two genes, which in combination result in male sterility. Further, the males are less fertile when heterozygous with a larger introgression, which suggests that dominant modifiers enhance the effects of recessive genes of male sterility. Such an epistatic view, even in the less-related species, suggests that the genetic complexity is special to hybrid male sterility.


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