Stabilization of Eu2+ in Li2B4O7 with the BO3 network through U6+ co-doping and defect engineering.

Owing to the unique 4f-5d transitions and the involvement of 5d electrons, the divalent europium (Eu2+) ion is extensively used as a dopant ion in luminescent materials for phosphor-converted light emitting diodes (pc-LEDs) and other technological applications. Earlier reports in most of the cases have shown that the reduction of Eu3+ to Eu2+ requires very high temperatures and large hydrogen flux. In this study, a co-doping strategy with higher valent U6+ ions was utilized to successfully stabilize Eu2+ ions in the Li2B4O7 (LTB) host with both the BO3 and BO4 network in low H2 flux of only 8%. It is postulated that charge transfer occurs from U to Eu, resulting in the reduction of the charged state of Eu and the reaction probably proceeds via the formation of paramagnetic transient [U5+-Eu3+] species in the co-doped LTB. The same is also believed to be facilitated by the enhanced formation of Li-O type vacancy clusters in co-doped samples and enhanced oxygen vacancies in a reducing atmosphere. We believe this work will pave a new pathway for stabilizing the unusual oxidation state of lanthanides and transition metal ions through co-doping with hexavalent uranium ions.

High titres of IgM-bound circulating immune complexes and erythrocytic oxidative damage are indicators of dengue severity.

Global incidence of dengue has drastically increased in the last few years. Despite the global morbidity and mortality associated with dengue infection, mechanisms of immune control and viral pathogenesis are poorly explored. Pancytopenias, along with increased oxidative stress, are salient clinical findings in severe dengue patients. Previously, we demonstrated significant differences of circulating immune complexes (CICs) among severe and non-severe dengue patients. Accordingly, here we sought to determine the contributory role of affinity-purified antibody-bound CICs in dengue severity. To characterize intracellular oxidative stress induced by antibody-bound CICs, 5-(and-6)-chloromethyl-2'-7'-dichlorodihydrofluorescein diacetate (DCFDA) was measured by flow cytometry. At the same time, CICs sensitized healthy red blood cells (RBC) and patients' RBC morphology was determined by scanning electron microscopy and flow cytometry analysis. Erythrophagocytosis and ferritin levels were further determined in severe and non-severe dengue patients. Our results showed that the severe patients had high titres of immunoglobulin (Ig)M-bound CICs (P < 0·0001) in their sera, increased intracellular oxidative stress (P < 0·0001), high ferritin levels (P < 0·0001), altered morphology of RBC and finally enhanced erythrophagocytosis. This study shows for the first time that RBC morphology is altered in severe dengue patients. Taken together, this study suggests that the enhanced IgM-bound CICs could contribute to the increased oxidative stress and act directly on RBC destruction of severe dengue patients, and is an important pathophysiological determinant. Hence, IgM-bound CICs can serve as an important laboratory parameter to monitor dengue infection progression.

Quality and Acceptability of Meat Nuggets with Fresh Aloe vera Gel.

Aloe vera has been used worldwide for pharmaceutical, food, and cosmetic industries due to its wide biological activities. However, quality improvement of low fat meat products and their acceptability with added Aloe vera gel (AVG) is scanty. The aim of this study was to explore the feasibility of using fresh AVG on physicochemical, textural, sensory and nutritive qualities of goat meat nuggets. The products were prepared with 0%, 2.5%, and 5% fresh AVG replacing goat meat and were analyzed for proximate composition, physicochemical and textural properties, fatty acid profile and sensory parameters. Changes in lipid oxidation and microbial growth of nuggets were also evaluated over 9 days of refrigerated storage. The results showed that AVG significantly (p<0.05) decreased the pH value and protein content of meat emulsion and nuggets. Product yield was affected at 5% level of gel. Addition of AVG in the formulation significantly affected the values of texture profile analysis. The AVG reduced the lipid oxidation and microbial growth in nuggets during storage. Sensory panelists preferred nuggets with 2.5% AVG over nuggets with 5% AVG. Therefore, AVG up to 2.5% level could be used for quality improvement in goat meat nuggets without affecting its sensorial, textural and nutritive values.

Seroprevalence of Trypanosoma evansi in cattle and analysis of associated climatic risk factors in Mizoram, India.

Surra, a haemoprotozoan parasitic disease even in subclinical form poses a challenge in terms of diagnosis and management to animal health practitioners and policy makers as well; eventually imparting financial loss to the livestock holders. A systematic study was designed to assess the seroprevalence of surra in cattle and associated climatic risk factors, by collecting 480 serum samples across the eight districts of Mizoram during 2017-2019. The apparent and true seroprevalence detected by card agglutination test was 37.08% (CI at 95%: 32.88-41.49) and 36.59% (CI at 95%: 32.4-40.99) whereas by recombinant Variable Surface Glycoprotein based indirect ELISA was 41.88% (CI at 95%: 37.5-46.3) and 40.35% (CI at 95%: 36.02-44.76) respectively. Climate parameters which influence vector population were extracted from their respective database and were correlated with seroprevalence data. Linear discriminant analysis revealed that air temperature, relative humidity and diurnal temperature range, leaf area index and soil moisture as significant risk factors discriminating seropositive and seronegative data sets classified by indirect ELISA. This study is the first report on seroprevalence of surra in cattle of Mizoram and the situation demands deployment of intervention strategies in order to assess the endemicity of the disease and thereby preventing the economic losses.

Mining the pervasiveness of surra in different animal species of Northeastern states of India: Assam, Mizoram and Tripura.

Trypanosoma evansi is a flagellated, extracellular haemoprotozoan parasite infecting a wide range of mammalian hosts including dromedaries, cattle, equines and dogs cause disease surra. Carrier animals with sub-clinical infection cause significant monetary losses to livestock holders and therefore detection of infection status using molecular diagnostic techniques becomes important in order to control the disease. In the current study cattle, buffalo, goat, pig and dog samples from three northeastern states of India-Assam, Mizoram and Tripura were screened to determine the prevalence of surra. A total of 1702 samples including 795 from Assam, 678 from Mizoram and 229 from Tripura were screened by CATT/T. evansi test out of which 16.8%, 27.1% and 22.3% samples in respective states were found to have antibodies against T. evansi. DNA detection of T. evansi by PCR amplification targeting VSG gene revealed the molecular prevalence of surra in Assam, Mizoram and Tripura as 8.5%, 7.5% and 4.4% respectively. The analysis of amplified partial VSG sequences showed 99% similarity within an animal species whereas 86-94% similarity was observed among different species of animals revealing the homogeneity. The study established the prevalence of surra in different species of animals in the three northeastern states of India-Assam, Mizoram and Tripura and this study is the first report of T. evansi infection in pig and goat from India. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12639-021-01392-z.

Identification and characterization of Bacillus anthracis by multiplex PCR analysis of sequences on plasmids pXO1 and pXO2 and chromosomal DNA.

Bacillus anthracis can be identified on the basis of the detection of virulence factor genes located on two plasmids, pXO1 and pXO2. Thus isolates lacking both pXO1 and pXO2 are indistinguishable from closely related B. cereus group bacteria. We developed a multiplex PCR assay for characterization of B. anthracis isolates, and simultaneous confirmation of the species identity independent of plasmid content. The assay amplifies lef, cya, pag (pXO1) and cap (pXO2) genes, and a B. anthracis specific chromosomal marker, giving an easy-to-read profile. This system unambiguously identified virulent (pXO1+/2+) and avirulent (pXO1+/2-, pXO1-/2+ and pXO1-/2-) strains of B. anthracis and distinguished "anthrax-like' strains from other B. cereus group bacteria.

Antibiotic susceptibility of isolates of Bacillus anthracis, a bacterial pathogen with the potential to be used in biowarfare.

Bacillus anthracis is a bacterial species that could be used in a bioterrorist attack. We tested a collection of isolates with a range of relevant antimicrobial compounds. All isolates tested were susceptible to ciprofloxacin and doxycycline. Penicillin and amoxicillin, with or without clavulanate, showed in vitro activity against all B. anthracis isolates. Ceftriaxone demonstrated lower-level in vitro activity compared to penicillin-related compounds against B. anthracis. In vitro data from this study are in keeping with available guidelines.

Isolation of a specific chromosomic DNA sequence of Bacillus anthracis and its possible use in diagnosis.

A 277-bp long DNA fragment, Ba813, was isolated from an avirulent Bacillus anthracis strain 7700 genomic library. Two oligonucleotides derived from the Ba813 sequence were used as primers in polymerase chain reaction tests on genomic DNA from 28 Bacillus anthracis and from 33 heterologous bacteria strains. A specific, 152-bp long DNA fragment was amplified only when Bacillus anthracis DNA was used as the target. The amplified product was analysed by non-radioactive sandwich hybridisation in microtiter plates using two oligonucleotides. The capture oligonucleotide C1 was covalently linked onto aminated wells of microtiter plates. The detection oligonucleotide D3 was labelled with biotine. The hybrid molecules were detected by avidine conjugated with alkaline phosphatase and chromogenic substrate. Amplification of Ba813 sequence may provide the basis for rapid and reliable assay for the detection and identification of Bacillus anthracis.

The Ba813 chromosomal DNA sequence effectively traces the whole Bacillus anthracis community.

Plasmid genes that are responsible for virulence of Bacillus anthracis are important targets for the DNA-based detection of anthrax. We evaluated the distribution of the Ba813 chromosomal DNA sequence (Ba813) within closely related Bacillus species. Ba813 was systematically identified from 47 strains or isolates of B. anthracis tested, thus indicating its reliability as a tracer for that species. From the 60 strains of closely related Bacillus spp. examined, three bona fide B. cereus and one bona fide B. thuringiensis were found to harbour Ba813. This marker was also detected in Bacillus sp. isolates that were present at high levels in soil samples collected in a place where an anthrax outbreak had occurred. The significance and the possible function of the Ba813 locus is discussed.

Quantitation of polymerase chain reaction-amplified DNA fragments by capillary electrophoresis and laser-induced fluorescence detection.

Quantitation of DNA fragments amplified by polymerase chain reaction (PCR) is needed for the determination of target DNA in molecular biology. Capillary electrophoresis in entangled polymer solution coupled to laser-induced fluorescence detection was assessed as an alternative technique to conventional slab gel methods to monitor competitive PCR, which consists of amplifying an internal standard fragment under the same conditions as the target fragment. The fluorescence signal was generated either through end-labeling of the fragments using 5'-fluorescein-labeled primers or through intercalation of ethidium bromide along the double strand. It is shown that the more accurate and reliable results were obtained using this latter pathway.

Molecular characterization of Bacillus strains involved in outbreaks of anthrax in France in 1997.

Outbreaks of anthrax zoonose occurred in two regions of France in 1997. Ninety-four animals died, and there were three nonfatal cases in humans. The diagnosis of anthrax was rapidly confirmed by bacteriological and molecular biological methods. The strains of Bacillus anthracis in animal and soil samples were identified by a multiplex PCR assay. They all belonged to the variable-number tandem repeat (VNTR) group (VNTR)3. A penicillin-resistant strain was detected. Nonvirulent bacilli related to B. anthracis, of all VNTR types, were also found in the soil.

Utilization of the rpoB gene as a specific chromosomal marker for real-time PCR detection of Bacillus anthracis.

The potential use of Bacillus anthracis as a weapon of mass destruction poses a threat to humans, domesticated animals, and wildlife and necessitates the need for a rapid and highly specific detection assay. We have developed a real-time PCR-based assay for the specific detection of B. anthracis by taking advantage of the unique nucleotide sequence of the B. anthracis rpoB gene. Variable region 1 of the rpoB gene was sequenced from 36 Bacillus strains, including 16 B. anthracis strains and 20 other related bacilli, and four nucleotides specific for B. anthracis were identified. PCR primers were selected so that two B. anthracis-specific nucleotides were at their 3' ends, whereas the remaining bases were specific to the probe region. This format permitted the PCR reactions to be performed on a LightCycler via fluorescence resonance energy transfer (FRET). The assay was found to be specific for 144 B. anthracis strains from different geographical locations and did not cross-react with other related bacilli (175 strains), with the exception of one strain. The PCR assay can be performed on isolated DNA as well as crude vegetative cell lysates in less than 1 h. Therefore, the rpoB-FRET assay could be used as a new chromosomal marker for rapid detection of B. anthracis.

Use of long-range repetitive element polymorphism-PCR to differentiate Bacillus anthracis strains.

The genome of Bacillus anthracis is extremely monomorphic, and thus individual strains have often proven to be recalcitrant to differentiation at the molecular level. Long-range repetitive element polymorphism-PCR (LR REP-PCR) was used to differentiate various B. anthracis strains. A single PCR primer derived from a repetitive DNA element was able to amplify variable segments of a bacterial genome as large as 10 kb. We were able to characterize five genetically distinct groups by examining 105 B. anthracis strains of diverse geographical origins. All B. anthracis strains produced fingerprints comprising seven to eight bands, referred to as "skeleton" bands, while one to three "diagnostic" bands differentiated between B. anthracis strains. LR REP-PCR fingerprints of B. anthracis strains showed very little in common with those of other closely related species such as B. cereus, B. thuringiensis, and B. mycoides, suggesting relative heterogeneity among the non-B. anthracis strains. Fingerprints from transitional non-B. anthracis strains, which possessed the B. anthracis chromosomal marker Ba813, scarcely resembled those observed for any of the five distinct B. anthracis groups that we have identified. The LR REP-PCR method described in this report provides a simple means of differentiating B. anthracis strains.