scholarly journals Genetic Analysis of Two Sympatric Sea Urchins from Genus Diadema (Echinodermata: Echinoidea: Diadematidae) from Malaysian Borneo

1970 ◽  
Vol 5 (1) ◽  
pp. 16-25
Author(s):  
Nursyuhaida Md Shahid ◽  
Raymie Nurhassan ◽  
Siti Akmar Khadijah Ab Rahim ◽  
Ruhana Hassan

Genus Diadema (Echinoidea: Diadematidae) has been reported to be the most widespread and ecologically important shallow water tropical sea urchins. Morphological variations and species distributions are complicated to elucidate due to complexity in making reliable identifications. Genus Diadema had involved in many debates, particularly on the mode of speciation and the specific status of Diadema setosum and Diadema savignyi. Therefore, relationships among Diadema species found in Malaysian Borneo have been examined using 16S rRNA gene analysis. Monophyletic clade of genus Diadema with respect to the outgroup was obtained with high bootstrap values of 100% (MP), 100% (NJ), 100% (ML) and Bayesian Posterior Probability is equal to 1.00. Two monophyletic clades were apparent separating D. setosum (Clade I) and D. savignyi (Clade II), with strong support of 100% (MP), 100% (NJ), 80% (ML) and Bayesian Posterior Probability is equal to 1.00. In addition, high genetic variation among species had been recorded (9.85%), suggesting that D. setosum and D. savignyi are two distinct entities. Furthermore, D. setosum and D. savignyi are sympatric species based on their distribution and overlapping ranges in Malaysian Borneo.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Cheng-Siang Tan ◽  
Vaenessa Noni ◽  
Jaya Seelan Sathiya Seelan ◽  
Azroie Denel ◽  
Faisal Ali Anwarali Khan

Abstract Objective Coronaviruses (CoVs) are natural commensals of bats. Two subgenera, namely Sarbecoviruses and Merbecoviruses have a high zoonotic potential and have been associated with three separate spillover events in the past 2 decades, making surveillance of bat-CoVs crucial for the prevention of the next epidemic. The study was aimed to elucidate the presence of coronavirus in fresh bat guano sampled from Wind Cave Nature Reserve (WCNR) in Sarawak, Malaysian Borneo. Samples collected were placed into viral transport medium, transported on ice within the collection day, and preserved at − 80 °C. Nucleic acid was extracted using the column method and screened using consensus PCR primers targeting the RNA-dependent RNA polymerase (RdRp) gene. Amplicons were sequenced bidirectionally using the Sanger method. Phylogenetic tree with maximum-likelihood bootstrap and Bayesian posterior probability were constructed. Results CoV-RNA was detected in ten specimens (47.6%, n  = 21). Six alphacoronavirus and four betacoronaviruses were identified. The bat-CoVs can be phylogenetically grouped into four novel clades which are closely related to Decacovirus-1 and Decacovirus-2, Sarbecovirus, and an unclassified CoV. CoVs lineages unique to the Island of Borneo were discovered in Sarawak, Malaysia, with one of them closely related to Sarbecovirus. All of them are distant from currently known human coronaviruses.


2021 ◽  
Vol 9 (6) ◽  
pp. 1307
Author(s):  
Sebastian Böttger ◽  
Silke Zechel-Gran ◽  
Daniel Schmermund ◽  
Philipp Streckbein ◽  
Jan-Falco Wilbrand ◽  
...  

Severe odontogenic abscesses are regularly caused by bacteria of the physiological oral microbiome. However, the culture of these bacteria is often prone to errors and sometimes does not result in any bacterial growth. Furthermore, various authors found completely different bacterial spectra in odontogenic abscesses. Experimental 16S rRNA gene next-generation sequencing analysis was used to identify the microbiome of the saliva and the pus in patients with a severe odontogenic infection. The microbiome of the saliva and the pus was determined for 50 patients with a severe odontogenic abscess. Perimandibular and submandibular abscesses were the most commonly observed diseases at 15 (30%) patients each. Polymicrobial infections were observed in 48 (96%) cases, while the picture of a mono-infection only occurred twice (4%). On average, 31.44 (±12.09) bacterial genera were detected in the pus and 41.32 (±9.00) in the saliva. In most cases, a predominantly anaerobic bacterial spectrum was found in the pus, while saliva showed a similar oral microbiome to healthy individuals. In the majority of cases, odontogenic infections are polymicrobial. Our results indicate that these are mainly caused by anaerobic bacterial strains and that aerobic and facultative anaerobe bacteria seem to play a more minor role than previously described by other authors. The 16S rRNA gene analysis detects significantly more bacteria than conventional methods and molecular methods should therefore become a part of routine diagnostics in medical microbiology.


The Auk ◽  
2021 ◽  
Author(s):  
Joseph A Tobias ◽  
Paul F Donald ◽  
Rob W Martin ◽  
Stuart H M Butchart ◽  
Nigel J Collar

AbstractSpecies are fundamental to biology, conservation, and environmental legislation; yet, there is often disagreement on how and where species limits should be drawn. Even sophisticated molecular methods have limitations, particularly in the context of geographically isolated lineages or inadequate sampling of loci. With extinction rates rising, methods are needed to assess species limits rapidly but robustly. Tobias et al. devised a points-based system to compare phenotypic divergence between taxa against the level of divergence in sympatric species, establishing a threshold to guide taxonomic assessments at a global scale. The method has received a mixed reception. To evaluate its performance, we identified 397 novel taxonomic splits from 328 parent taxa made by application of the criteria (in 2014‒2016) and searched for subsequent publications investigating the same taxa with molecular and/or phenotypic data. Only 71 (18%) novel splits from 60 parent taxa have since been investigated by independent studies, suggesting that publication of splits underpinned by the criteria in 2014–2016 accelerated taxonomic decisions by at least 33 years. In the evaluated cases, independent analyses explicitly or implicitly supported species status in 62 (87.3%) of 71 splits, with the level of support increasing to 97.2% when excluding subsequent studies limited only to molecular data, and reaching 100% when the points-based criteria were applied using recommended sample sizes. Despite the fact that the training set used to calibrate the criteria was heavily weighted toward passerines, splits of passerines and non-passerines received equally strong support from independent research. We conclude that the method provides a useful tool for quantifying phenotypic divergence and fast-tracking robust taxonomic decisions at a global scale.


2005 ◽  
Vol 19 (3) ◽  
pp. 209 ◽  
Author(s):  
Thuy T. T. Nguyen ◽  
Christopher M. Austin

The phylogenetic relationships among 32 individuals of Australian freshwater crayfish belonging to the Cherax destructor-complex were investigated using a dataset comprising sequences from four mitochondrial gene regions: the large subunit rRNA (16S rRNA), cytochrome oxidase I (COI), adenosine triphosphatase 6 (ATPase 6), and cytochrome oxidase III (COIII). A total of 1602 bp was obtained, and a combined analysis of the data produced a tree with strong support (bootstrap values 94–100%) for three divergent lineages, verifying the phylogenetic hypotheses of relationships within the C. destructor species-complex suggested in previous studies. Overall, sequences from the 16S rRNA gene showed the least variation compared to those generated from protein coding genes, which presented considerably greater levels of divergence. The level of divergence within C. destructor was found to be greater than that observed in other species of freshwater crayfish, but interspecific variation among species examined in the present study was similar to that reported previously.


2021 ◽  
Vol 11 (6) ◽  
pp. 2875
Author(s):  
A.V. Safonov ◽  
A.E. Boguslavsky ◽  
O.L. Gaskova ◽  
K.A. Boldyrev ◽  
O.S. Shvartseva ◽  
...  

Nitrate is a substance which influences the prevailing redox conditions in groundwater, and in turn the behaviour of U. The study of groundwater in an area with low-level radioactive sludge storage facilities has shown their contamination with sulphate and nitrate anions, uranium, and some associated metals. The uranyl ion content in the most contaminated NO3–Cl–SO4–Na borehole is 2000 times higher (1.58 mg/L) than that in the background water. At the same time, assessment of the main physiological groups of microorganisms showed a maximum number of denitrifying and sulphate-reducing bacteria (e.g., Sulfurimonas) in the water from the same borehole. Biogenic factors of radionuclide immobilization on sandy rocks of upper aquifers have been experimentally investigated. Different reduction rates of NO3-, SO42-, Fe(III) and U(VI) with stimulated microbial activity were dependent on the pollution degree. Moreover, 16S rRNA gene analysis of the microbial community after whey addition revealed a significant decrease in microbial diversity and the activation of nonspecific nitrate-reducing bacteria (genera Rhodococcus and Rhodobacter). The second influential factor can be identified as the formation of microbial biofilms on the sandy loam samples, which has a positive effect on U sorption (an increase in Kd value is up to 35%). As PHREEQC physicochemical modelling numerically confirmed, the third most influential factor that drives U mobility is the biogenic-mediated formation of a sulphide redox buffer. This study brings important information, which helps to assess the long-term stability of U in the environment of radioactive sludge storage facilities.


Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 916
Author(s):  
Sebastian Böttger ◽  
Silke Zechel-Gran ◽  
Daniel Schmermund ◽  
Philipp Streckbein ◽  
Jan-Falco Wilbrand ◽  
...  

Odontogenic abscesses are usually caused by bacteria of the oral microbiome. However, the diagnostic culture of these bacteria is often prone to errors and sometimes fails completely due to the fastidiousness of the relevant bacterial species. The question arises whether additional pathogen diagnostics using molecular methods provide additional benefits for diagnostics and therapy. Experimental 16S rRNA gene analysis with next-generation sequencing (NGS) and bioinformatics was used to identify the microbiome of the pus in patients with severe odontogenic infections and was compared to the result of standard diagnostic culture. The pus microbiome was determined in 48 hospitalized patients with a severe odontogenic abscess in addition to standard cultural pathogen detection. Cultural detection was possible in 41 (85.42%) of 48 patients, while a pus-microbiome could be determined in all cases. The microbiomes showed polymicrobial infections in 46 (95.83%) cases, while the picture of a mono-infection occurred only twice (4.17%). In most cases, a predominantly anaerobic spectrum with an abundance of bacteria was found in the pus-microbiome, while culture detected mainly Streptococcus, Staphylococcus, and Prevotella spp. The determination of the microbiome of odontogenic abscesses clearly shows a higher number of bacteria and a significantly higher proportion of anaerobes than classical cultural methods. The 16S rRNA gene analysis detects considerably more bacteria than conventional cultural methods, even in culture-negative samples. Molecular methods should be implemented as standards in medical microbiology diagnostics, particularly for the detection of polymicrobial infections with a predominance of anaerobic bacteria.


2015 ◽  
Vol 65 (Pt_7) ◽  
pp. 2320-2325 ◽  
Author(s):  
Shih-Yao Lin ◽  
Asif Hameed ◽  
Cheng-Zhe Wen ◽  
You-Cheng Liu ◽  
Yi-Han Hsu ◽  
...  

A Gram-stain-negative, aerobic, rod-shaped, yellow-pigment-producing bacterium (designated strain CC-CZW007T) was isolated from seafood samples (sea urchins) at Penghu Island in Taiwan. Strain CC-CZW007T grew optimally at pH 7.0 and 30 °C in the presence of 3 % (w/v) NaCl. The novel strain shared highest 16S rRNA gene sequence similarity to Vitellibacter vladivostokensis JCM 11732T (96.8 %), Vitellibacter soesokkakensis KCTC 32536T (96.4 %), Vitellibacter nionensis KCTC 32420T (95.8 %) and Vitellibacter aestuarii JCM 15496T (95.6 %) and lower sequence similarity to members of other genera. Phylogenetic analyses based on 16S rRNA genes revealed a distinct taxonomic position attained by strain CC-CZW007T with respect to other species of the genus Vitellibacter. The major fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH. The polar lipid profile was composed of major amounts of phosphatidylethanolamine, unidentified lipids and aminolipids; a moderate amount of aminophospholipid was also detected. The DNA G+C content was 34.7 mol%. The predominant quinone system was menaquinone (MK-6). On the basis of polyphasic taxonomic evidence presented here, strain CC-CZW007T is proposed to represent a novel species within the genus Vitellibacter, for which the name Vitellibacter echinoideorum sp. nov. is proposed. The type strain is CC-CZW007T ( = BCRC 80886T = JCM 30378T).


Author(s):  
Priya Lakra ◽  
Helianthous Verma ◽  
Chandni Talwar ◽  
Durgesh Narain Singh ◽  
Nirjara Singhvi ◽  
...  

Deinococcus species are widely studied due to their utility in bioremediation of sites contaminated with radioactive elements. In the present study, we re-evaluated the taxonomic placement of two species of the genus Deinococcus namely D. swuensis DY59T and D. radiopugnans ATCC 19172T based on whole genome analyses. The 16S rRNA gene analysis revealed a 99.58% sequence similarity between this species pair that is above the recommended threshold value for species delineation. These two species also clustered together in both the 16S rRNA gene and core genome based phylogenies depicting their close relatedness. Furthermore, more than 98% of genes were shared between D. swuensi s DY59T and D. radiopugnans ATCC 19172T. Interestingly, D. swuensis DY59T and D. radiopugnans ATCC 19172T shared high genome similarity in different genomic indices. They displayed an average nucleotide identity value of 97.63%, an average amino acid identity value of 97% and a digital DNA–DNA hybridization value equal to 79.50%, all of which are well above the cut-off for species delineation. Altogether, based on these evidences, D. swuensis DY59T and D. radiopugnans ATCC 19172T constitute a single species. Hence, as per the priority of publication, we propose that Deinococcus swuensis Lee et al. 2015 should be reclassified as a later heterotypic synonym of Deinococcus radiopugnans .


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