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Saudi Arabia has the world's fifth-largest desert and is the biggest importer of food and agricultural products. Understanding soil microbial communities is key to improving the agricultural potential of the region. Therefore, soil microbial communities of the semiarid region of Abha, known for agriculture, and arid regions of Hafar Al Batin and Muzahmiya were studied using Illumina sequencing. The results show that the microbial communities of the Saudi desert were characterized by the presence of high numbers of Actinobacteria, Proteobacteria, and Firmicutes. In addition to Sahara desert signature phyla like Gemmatimonadetes, biogeochemically important microorganisms like primary producers, nitrogen fixers and ammonia oxidizers were also present. The composition of the microbial community varied greatly among the sites sampled. The highest diversity was found in the rhizospheric soil of Muzahmiya followed by Abha. Firmicutes, Proteobacteria and Actinobacteria were the three main phyla detected in all the samples. Soils from the agricultural region of Abha were significantly different from other samples in containing only 1 % Firmicutes and 3–6 times higher population of Actinobacteria and Bacteroidetes, respectively. The presence of photosynthetic bacteria, ammonia oxidizers, and nitrogen fixers along with bacteria capable of surviving on simple and unlikely carbon sources like dimethylformamide was indicative of their survival strategies under harsh environmental conditions in the arid soil. Functional inference using PICRUSt analysis shows an abundance of genes involved in photosynthesis and nitrogen fixation.

The effective interactions of nanomaterials with biological constituents play a significant role in enhancing their biomedicinal properties. These interactions can be efficiently enhanced by altering the surface properties of nanomaterials. In this study, we demonstrate the method of altering the surface properties of ZrO2 nanoparticles (NPs) to enhance their antimicrobial properties. To do this, the surfaces of the ZrO2 NPs prepared using a solvothermal method is functionalized with glutamic acid, which is an α-amino acid containing both COO- and NH4 + ions. The binding of glutamic acid (GA) on the surface of ZrO2 was confirmed by UV-visible and Fourier transform infrared spectroscopies, whereas the phase and morphology of resulting GA-functionalized ZrO2 (GA-ZrO2) was identified by X-ray diffraction and transmission electron microscopy. GA stabilization has altered the surface charges of the ZrO2, which enhanced the dispersion qualities of NPs in aqueous media. The as-prepared GA-ZrO2 NPs were evaluated for their antibacterial properties toward four strains of oral bacteria, namely, Rothia mucilaginosa, Rothia dentocariosa, Streptococcus mitis, and Streptococcus mutans. GA-ZrO2 exhibited increased antimicrobial activities compared with pristine ZrO2. This improved activity can be attributed to the alteration of surface charges of ZrO2 with GA. Consequently, the dispersion properties of GA-ZrO2 in the aqueous solution have increased considerably, which may have enhanced the interactions between the nanomaterial and bacteria.

The use of probiotics to treat gastrointestinal diseases such as diarrhea especially in children is becoming increasingly popular. Besides, the use of nanomaterials in food products is increasing rapidly especially in candies and chocolates. How these nanomaterials influence probiotic bacteria and their activity remains unexplored. Therefore, nanomaterials from commercial chocolate were purified and characterized by using SEM-EDS and XRD. The tested chocolate contained nano-TiO2 with an average size of ~ 40 nm. The influence of the extracted TiO2 on a commercial probiotic formulation usually used to treat diarrhea in children was studied. The probiotic formulation contained Bacillus coagulans, Enterococcus faecalis, and Enterococcus faecium as evident from 16S rRNA gene sequences and polyphasic characterization. Isolated bacteria exhibited known probiotic activities like biofilm formation, acid production, growth at 6% salt, and antibiotic resistance. TiO2 from chocolates inhibited the growth and activity of the probiotic formulation over a concentration range of 125-500μg/ml in vitro. Based on results, it is estimated that 20 g of such chocolate contains enough TiO2 to disturb the gut microbial community of children aged 2-8 years with a stomach capacity of ~ 0.5-0.9 l. The in vivo study on white albino mice shows the same response but with a higher dose. The results obtained by plate counts, MTT assay, live/dead staining, and qPCR suggest that TiO2 from chocolates inhibits the growth and viability of probiotic bacteria in mice gut even at a concentration of 50-100 μg/day/mice. Therefore, TiO2 in chocolate discourages survival of probiotic bacteria in the human gut.

Understanding the microbial communities in anaerobic digesters, especially bacteria and archaea, is key to its better operation and regulation. Microbial communities in the anaerobic digesters of the Gulf region where climatic conditions and other factors may impact the incoming feed are not documented. Therefore, Archaeal and Bacterial communities of three full-scale anaerobic digesters, namely AD1, AD3, and AD5 of the Jebel Ali Sewage water Treatment Plant (JASTP) were analyzed by Illumina sequencing of 16S rRNA genes. Among bacteria, the most abundant genus was fermentative bacteria Acetobacteroides (Blvii28). Other predominant bacterial genera in the digesters included thermophilic bacteria (Fervidobacterium and Coprothermobacter) and halophilic bacteria like Haloterrigena and Sediminibacter. This can be correlated with the climatic condition in Dubai, where the bacteria in the incoming feed may be thermophilic or halophilic as much of the water used in the country is desalinated seawater. The predominant Archaea include mainly the members of the phyla Euryarchaeota and Crenarchaeota belonging to the genus Methanocorpusculum, Metallosphaera, Methanocella, and Methanococcus. The highest population of Methanocorpusculum (more than 50% of total Archaea), and other hydrogenotrophic archaea, is in agreement with the high population of bacterial genera Acetobacteroides (Blvii28) and Fervidobacterium, capable of fermenting organic substrates into acetate and H2. Coprothermobacter, which is known to improve protein degradation by establishing syntrophy with hydrogenotrophic archaea, is also one of the digesters’ dominant genera. The results suggest that the microbial community in three full-scale anaerobic digesters is different. To best of our knowledge this is the first detailed report from the UAE.

Humans have witnessed three deadly pandemics so far in the twenty-first century which are associated with novel coronaviruses: SARS, Middle East respiratory syndrome (MERS), and COVID-19. All of these viruses, which are responsible for causing acute respiratory tract infections (ARTIs), are highly contagious in nature and/or have caused high mortalities. The recently emerged COVID-19 disease is a highly transmittable viral infection caused by another zoonotic novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Similar to the other two coronaviruses such as SARS-CoV-1 and MERS-CoV, SARS-CoV-2 is also likely to have originated from bats, which have been serving as established reservoirs for various pathogenic coronaviruses. Although, it is still unknown how SARS-CoV-2 is transmitted from bats to humans, the rapid human-to-human transmission has been confirmed widely. The disease first appeared in Wuhan, China, in December 2019 and quickly spread across the globe, infected 48,539,872 people, and caused 1,232,791 deaths in 215 countries, and the infection is still spreading at the time of manuscript preparation. So far, there is no definite line of treatment which has been approved or vaccine which is available. However, different types of potential vaccines and therapeutics have been evaluated and/or are under clinical trials against COVID-19. In this review, we summarize different types of acute respiratory diseases and briefly discuss earlier outbreaks of coronaviruses and compare their occurrence and pathogenicity with the current COVID-19 pandemic. Various epidemiological aspects of COVID-19 such as mode of spread, death rate, doubling time, etc., have been discussed in detail. Apart from this, different technical issues related to the COVID-19 pandemic including use of masks and other socio-economic problems associated with the pandemic have also been summarized. Additionally, we have reviewed various aspects of patient management strategies including mechanism of action, available diagnostic tools, etc., and also discussed different strategies for the development of effective vaccines and therapeutic combinations to deal with this viral outbreak. Overall, by the inclusion of various references, this review covers, in detail, the most important aspects of the COVID-19 pandemic.

Extended-spectrum beta-lactamase (ESBL) producing bacteria of the Enterobacteriaceae family are a significant threat to public health, posing a challenge for health authorities worldwide. In the UAE, very little information is available about ESBL producing bacteria from non-clinical sources. In this study, 206 pure cultures belonging to the Enterobacteriaceae family were isolated from food and wastewater sources in Dubai, UAE. All the isolates were tested against third-generation cephalosporin antibiotics by the disc diffusion method and screened on ESBL chromogenic agar. Among all isolates (n = 86), 41.7% were potential ESBL producers belonging to E. coli, Klebsiella, Enterobacter, Shigella, and Citrobacter (KESC group), and Proteus. Of all the potential ESBL producing isolates, 19 (22%) were confirmed as ESBL producers by a double-disc diffusion test with the fourth generation cephalosporin&ndash, Cefpirome. The multiplex polymerase chain reaction was used for the detection of ESBL bla genes in the screened isolates. Out of a total of 86 isolates, 52.3% possessed only the blaTEM gene, 39.5% contained both blaTEM and blaSHV genes, while only 3.5% contained the blaCTX-M gene. The carbapenemase resistance test showed eight isolates resistant to imipenem, and only one isolate with metallo-beta-lactamase activity. This study highlights the occurrence of ESBL bla genes among non-clinical isolates from food and wastewater sources in the UAE and emphasizes the importance of food and wastewater surveillance programs in controlling the spread of antibiotic resistance.

Understanding the microbial communities in anaerobic digesters is important for better regulation, operation, and sustainable management of the sludge produced at various stages of wastewater treatment processes. Microbial communities in the anaerobic digester of the gulf region where the climatic conditions and other factors may impact the incoming feed have not been documented. Archaeal and Bacterial communities of three full-scale anaerobic digesters, namely AD1, AD3 and AD5 were analyzed by Illumina sequencing of 16S rRNA genes. Among bacteria, the most abundant genus was fermentative bacteria Acetobacteroides (Blvii28). Other predominant bacterial genera in the digesters included thermophilic bacteria (Fervidobacterium and Coprothermobacter) and halophilic bacteria like Haloterrigena and Sediminibacter. This can be correlated with the climatic condition in Dubai, where the bacteria in the original feed may be thermophilic or halophilic as much of the water used in the country is desalinated seawater. Propionic acid-producing bacteria like Paludibacter and propionate oxidizing bacteria like W5 were also dominating group and were found in all the digesters. The predominant Archaea include mainly the members of phylum Euryarchaeota and Crenarchaeota belonging to genus Methanocorpusculum, Metallosphaera, Methanocella, and Methanococcus. The highest population of Methanocorpusculum (more than 50% of total Archaea) hydrogenotrophic archaea matches with the high population of Acetobacteroides (Blvii28) and Fervidobacterium bacteria which ferments the organic substrates to acetate and H2. Coprothermobacter, which is known to improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea, was also one of the dominant genera in the digesters. This study, for the first time, contributes to an in-depth understanding of the phylogenetic diversity of a microbial community of three full-scale anaerobic digesters of a municipal wastewater treatment plant in Dubai, UAE.

Clean water is vital for life; it is required not only for drinking but also for the preparation of food and proper hygiene. Unfortunately, more than fifty percent of the world population mainly in China and India face a severe scarcity of water. Around 1.8 billion people inevitably drink water from sources having fecal contamination resulting in the death of about a million children every year. Scientists are developing various economic technologies to decontaminate and purify water. Nanomaterials-based technology offers an economic and effective alternative for water purification and decontamination. As nanomaterials are available globally, have remarkable antimicrobial activity and the ability to effectively remove organic and inorganic pollutants from water. This review discusses the potential role of nanomaterials in the purification of drinking water. As nanomaterials exhibit remarkable antimicrobial and antiparasitic activities against waterborne pathogens and parasites of primary concern like Shigella dysenteriae, Vibrio cholera, and Entamoeba histolytica. Nanomaterials also demonstrate the ability to absorb toxic chemicals like mercury and dyes from polluted water. However, for successful commercialization of the technology, some inherent bottlenecks need to be addressed adequately. These include nanoparticles aggregation, their seepage into drinking water and adverse effects on human health and the environment. Nanocomposites are being developed to overcome these problems and to combine two or more desirable properties for water purification. Widespread and large-scale use of nanomaterials for water purification soon may become a reality. Products containing nanomaterials such as Karofi, Lifestraw, and Tupperware for water purification are already available in the market.

The essential oil and aqueous distillate composition of Origanum vulgare L. were analyzed by GC/MS. Sixty-seven different components were detected in both oils. Sixty-four components were characterized for the oil derived from the aerial parts, whereas thirty-three components in the volatile oil from the aqueous distillates of O. vulgare L., representing 99.8% and 98.5% of the oils, respectively. The main components of the volatile oil from the aerial parts of O. vulgare L. were carvacrol (70.2 ± 1.37%), γ-terpinene (5.6 ± 0.11%), p-cymene (4.5 ± 0.42%), trans-sabinene hydrate (3.8 ± 0.07%), and thymol (2.2 ± 0.12%). In comparison, the main compounds of the volatile oil of the O. vulgare L. aqueous distillates were carvacrol (92.5 ± 0.97%), thymol (2.5 ± 0.09%), and terpinen-4-ol (1.0 ± 0.03%). The antibacterial activity of both oils, along with that of the purified major component, carvacrol, against Gram-positive and Gram-negative strains was assessed. The results revealed that all three samples showed significant antibacterial activity against all tested strains. The IC50 values of the oils derived from the aerial parts and aqueous distillates of O. vulgare L. against the tested strains was in the range of 107–383 µg·mL−1, whereas, the IC50 value of carvacrol was in the range of 53–151 µg·mL−1. The data suggest that carvacrol, a major component of both oils, possesses the highest antibacterial activity of all the constituents and is the main component responsible for the antibacterial activity of Saudi O. vulgare L. oils.

The present study was carried out to assess the role of zinc oxide nanoparticles (ZnO-NPs) in tomato plants on growth, photosynthetic efficiency, and antioxidant system. At 20-d stage of growth, roots of tomato plants were dipped into 0, 2, 4, 8, or 16 mg(ZnO-NPs) L–1 for 15, 30, and 45 min and then seedlings were transplanted in their respective cups and allowed to grow under natural environmental conditions. At 45-d stage of growth, the ZnO-NPs treatments significantly increased growth, photosynthetic efficiency together with activities of carbonic anhydrase and antioxidant systems in a concentration- and duration-dependent manner. Moreover, the treatment by 8 mg(ZnO-NPs) L–1 for 30 min proved to be the most effective and resulted in maximum activities of antioxidant enzymes, proline accumulation and the photosynthetic rate. We concluded that presence of ZnO-NPs improved the antioxidant systems and speeded up proline accumulation that could provide stability to plants and improved photosynthetic efficiency.

Introduction:Anaerobic digestion for methane production comprises of an exceptionally diverse microbial consortium, a profound understanding about which is still constrained. In this study, the methanogenic archaeal communities in three full-scale anaerobic digesters of a Municipal Wastewater Treatment Plant were analyzed by Fluorescencein situhybridization and quantitative real-time Polymerase Chain Reaction (qPCR) technique.Methods & Materials:Fluorescencein situhybridization (FISH) was performed to detect and quantify the methanogenicArchaeain the sludge samples whereas qPCR was carried out to support the FISH analysis. Multiple probes targeting domain archaea, different orders and families of Archaea were used for the studies.Results and Discussion:In general, the aceticlastic organisms(Methanosarcinaceae & Methanosaetaceae)were more abundant than the hydrogenotrophic organisms(Methanobacteriales, Methanomicrobiales, Methanobacteriaceae & Methanococcales). Both FISH and qPCR indicated that familyMethanosaetaceaewas the most abundant suggesting that aceticlastic methanogenesis is probably the dominant methane production pathway in these digesters.Conclusion:Future work involving high-throughput sequencing methods and correlating archaeal communities with the main operational parameters of anaerobic digesters will help to obtain a better understanding of the dynamics of the methanogenic archaeal community in wastewater treatment plants in United Arab Emirates (UAE) which in turn would lead to improved performance of anaerobic sludge digesters.

A new series of pyrazole-containing s-triazine derivatives were synthesized by reaction of the corresponding s-triazinyl hydrazine derivatives with acetylacetone in the presence of HClO 4 or DMF/TEA. The former method allowed the preparation of the target products with higher yields. All compounds were fully characterized. X-ray single crystal diffraction for two representative compounds (4-(4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)morpholine and N-benzyl-4-(3,5-dimethyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)-1,3,5-triazin-2-amine ) was studied and the molecular structures were optimized using the DFT/B3LYP method. The structures were found to be in agreement with X-ray structures. The antimicrobial and antifungal activity of the prepared compounds were tested against the growth of several microorganisms.

Eye lenses are exposed to thermal, solar radiations, dryness that enhances cataractogenesis. Some animal lenses contain novel proteins in bulk quantities. ζ-crystallin occurred in three ecologically divergent species, but it's physiological role not known. The truncated variant of ζ-crystallin causes hereditary cataract. Guinea pig ζ-crystallin is temperature-sensitive and rapidly aggregates at 41°C. Camels adopted to survive above 50°C, which raises an interesting question about how it retains lens proteins in the soluble state? Here, we have optimized expression and purification of recombinant camel ζ-crystallin. We have studied thermodynamic and spectroscopic properties using orthogonal techniques. Dynamic multimode spectroscopy results showed that camel ζ-crystallin unfolds via single transition with Tm value of 60.8±0.1°C and van't Hoff enthalpy of 714.7±7.1kJ/mol. Thermal-shift assay calculates Tm value of 62°C at pH 7. Additionally, the conformational stability of ζ-crystallin increases with ionic-strength. The influence of pH on ζ-crystallin was evaluated where the protein was found to be stable in the pH range of 6-9, but its stability drastically decreases below pH 6. Our results also showed that quaternary structure of ζ-crystallin drastically changed as a result of lowering pH. This study provides significant understandings onto the conformational, thermodynamic and unfolding pathway of camel ζ-crystallin.

Exoelectrogens are important microorganisms playing crucial roles in the biogeochemistry of elements in paddy soils. But it remains unclear how the soil properties and geographical distances affect the exoelectrogen communities of Chinese paddy soils. So the objectives of this study were to investigate the diversity and composition of these microbial communities which were enriched on the anodes of soil microbial fuel cells (SMFCs) and to elucidate the links between the microbial community compositions and their driving factors. We used Illumina HiSeq sequencing to determine the bacterial community structures which were enriched on the anodes of SMFCs. Variance partitioning analysis (VPA) was used to obtain the contribution of soil properties and geographical distance to the variations of bacterial communities. Active bacterial community on anodes of the closed circuit SMFCs differs significantly from the control open circuit SMFCs. Anodes of all the closed circuit SMFCs were characterized by the presence of high numbers of Nitrospira and Anaerolineae. Taxonomic similarities and phylogenetic similarities of bacterial communities from different paddy soil samples across North and South China were found to be significantly correlated with geographical distances. The relationship between the similarities and the geographic distance exhibited a distance-decay relationship. VPA showed that both geographical distances and soil properties affect the structure of bacterial communities detected on anodes. Our study gives a foundation for understanding the distribution and diversity of exoelectrogens in paddy soils and elucidates the links between the distribution and the diversity of extracellular respiring bacteria and their driving factors. Furthermore, this study also identifies the crucial factors which should be used to evaluate the response of exoelectrogens to environmental perturbations in Chinese paddy soils.

A large numbe of nanomaterials-based products are being commercially engineered and produced. Many of these engineered nanomaterials (ENMs) are disposed in soil in significant quantities. Furthermore, nanomaterials are being specially tailored for use in agriculture as nano-fertilizers, nano-pesticides, and nano-based biosensors. The behavior of ENMs in soil and their persistence depends on their chemical nature and soil characteristics. Furthermore, nanoparticles like silver and zinc oxide possess well-known antimicrobial activities. The presence and persistence of these nanomaterials in soil can alter the quality of the soil microbiome, thus influencing key microbial processes like mineralization, nitrogen fixation and plant growth promoting activities. It is, therefore, extremely important to understand how nanomaterials influence the soil microbiome and associated chemical and biochemical processes. Such investigations will provide necessary information for eventual regulation of the appropriate use of nanomaterials for sustainable agriculture and increased agricultural productivity. This chapter discusses some of these issues.

Essential oils (EOs) from the stems and leaves of Origanum vulgare L. grown in Saudi Arabia and Jordan were analyzed by gas chromatography–mass spectrometry (GC–MS) and GC–flame ionization detector (FID) techniques on two different columns (polar and nonpolar). A detailed phytochemical analysis led to the identification of 153 constituents of these essential oils. Both Saudi and Jordanian plants are classified by chemotypes rich in cymyl-compounds. However, the Saudi Origanum contains carvacrol as the major component and is, thus, characterized as a carvacrol chemotype, while the Jordanian Origanum contains thymol as the major component, and, thus, it is classified as a thymol chemotype. In addition, the antimicrobial activities of the studied EOs and their major components, including carvacrol and thymol, were evaluated against various Gram-positive and Gram-negative microorganisms. All the tested compounds exhibited significant antimicrobial activity against all the tested bacteria. Among them, thymol demonstrated superior activity against all the tested organisms, followed by carvacrol. Moreover, results on oil composition and oil yield of O. vulgare L. from different parts of the world is compared in detail with the present outcomes.

A highly complex microbial community involved in anaerobic sludge digesters plays vital roles in sludge treatment. The data on microbial ecology is important to accomplish efficient operation of the anaerobic digesters. This study is aimed at monitoring the bacterial community of three full-scale anaerobic digesters of a full-scale municipal wastewater treatment Plant in Dubai, United Arab Emirates. Fluorescent in-situ hybridization technique was applied to identify the bacterial groups and quantitative polymerase chain reaction to compare the richness of bacterial and archaeal domain. Results of the fluorescent in-situ hybridization technique analysis showed that the phylum proteobacteriawas most abundant followed by cytophage-Flavobacterium group of Bacteroides, Firmicutes and Actinobacteria. Among proteobacterial subclass Delta- and Alpha- were dominating than Gamma- and Beta-proteobacteria. The genus Desulfobacter and Desulfobacterium were the dominant groups hybridizing 70-76% of total 4’, 6’‒ diamidino – 2 phenylindole stained cells. The quantitative polymerase chain reaction results showed that Bacterial domain was dominating in all three digesters compared to the Archaeal domain.

One fourth of the global mortalities is still caused by microbial infections largely due to the development of resistance against conventional antibiotics among pathogens, the resurgence of old infectious diseases and the emergence of hundreds of new infectious diseases. The lack of funds and resources for the discovery of new antibiotics necessitates the search for economic and effective alternative antimicrobial agents. Metal and metal oxide nanoparticles including silver and zinc oxide exhibit remarkable antimicrobial activities against pathogens and hence are one of the most propitious alternative antimicrobial agents. These engineered nanomaterials are approved by regulatory agencies such as USFDA and Korea's FITI, for use as antimicrobial agents, supplementary antimicrobials, food packaging, skin care products, oral hygiene, and for fortifying devices prone to microbial infections. Nevertheless, detailed studies, on molecular and biochemical mechanisms underlying their antimicrobial activity are missing. To take the full advantage of this emerging technology selective antimicrobial activity of these nanoparticles against pathogens should be studied. Optimization of these nanomaterials through functionalization to increase their efficacy and biocompatibility is also required. Urgent in vivo studies on the toxicity of nanomaterials at realistic doses are also needed before their clinical translation.

The global consumption of fruits and vegetables is rapidly increasing with the increasing world population and health awareness. Waste and by-products are produced in all the phases of the food life cycle i.e. during production, industrial processing, and distribution. It has been reported that in the food manufacturing industry 39% of the food is wasted and this is expected to rise to about 126 metric tonnes by 2020 if proper prevention policies are not in place. The by-products of these fruits and vegetables like peels can be wisely used for other industries. It has also been observed that a large portion of fruits and vegetables undergo a post harvest loss in the processing industry. For example, the pulp and the peel after the extraction of juices from fruits and vegetables go unutilized. The fruits, vegetables and their by products are rich in bioactive compounds like phenolic compounds, flavonoids, carotenoids, and anthocyanins. These compounds are known to have anticancer, antiviral, anti-tumour, antimicrobial and antioxidant activities; and can be used as pharmaceutical, nutraceuticals, cosmetic, chemical industries as well as for the development of functional foods. Since many of these bioactive compounds possess antimicrobial activity, they can also be used in food preservation and to control food-borne pathogens. Compounds from these by-products such as carotenoids, essential oils, and flavours can be included in food products to enhance their sensory properties and to improve their nutritional value and health benefits. The present chapter focuses on various types of bioactive compounds present in the by-products of fruits and vegetables, their extraction techniques, and their possible use as pharmaceuticals, cosmetics and in chemical industries. The antioxidant and antimicrobial properties of these bioactive compounds are also discussed.

The concept of probiotics although perceived as new is more than a century old. Since the early studies of the Elie Metchnikoff in 1903, a number of commercial products containing probiotics are in the market. The recent success of converting probiotic products into commercial reality was achieved by the scientists like Minoru Shirota and Kellog. Minoru Shirota is a Japanese scientist who successfully demonstrated the health benefits of probiotics and commercialized the globally known probiotic drink Yakult. This renewed interest in probiotics is spurred by the recent advances made in understanding the human microbiome and its role in human health. The link between the gut microbiome and human health is becoming increasingly clear and is well described. Nevertheless, the gut microbiome is continuously influenced by a number of factors like diet, lifestyle and consumption of antibiotics. A healthy gut microbiome can be retained and maintained by using various probiotics. Moreover, the probiotic microorganisms are no more limited to a few conventionally used bacteria and are being currently represented by more phylogenetically diverse microorganisms than previously thought. These probiotic microorganisms include conventionally used Lactic acid bacteria, like Lactobacillus and recently identified probiotic bacteria like Akkermansia muciniphila, Bifidobacterium infantis, Bacteroides fragilis, Clostridium butyricum, Faecalibacterium prausnitzii and Streptococcus thermophiles etc. Many of these probiotic strains have a shared mechanism of action, while strain specific, species-specific or genus-specific probiotic effects have also been documented. Probiotics are administered as live cultures or as spores, directly or through fermented dairy products, food, and drinks. Probiotics based therapies like fecal microbiota transplant are also being used successfully for treating medical conditions and diseases like diarrhea, constipation, vaginitis, necrotizing enterocolitis, inflammatory bowel disease, Clostridium difficile infection, and others. Reports showing a clear role of probiotics in immunomodulation, prevention of cardiovascular diseases and even cancer are also emerging. Yet, a number of microorganisms in the gut remain uncultured and many candidate probiotic microorganisms remain poorly identified, requiring correct identification and a rigorous evaluation as probiotics. Probiotics may be a century old but require fresh attention keeping in view the recent advances made in understanding the gut microbiome and the role of these microorganisms in human health.

DNA referred to as blueprint of life codes for the diversity and function of all the living organisms. Determining DNA sequences of the living organisms not only gives an overview of their genetic makeup, but also provides information about their function. Nonetheless it was not easy to determine the genome sequencing of all the diversity around us especially with the technologies available before 2010. Therefore, determining the sequence of humans and some other organisms only was prioritized. Pioneering methods for DNA sequencing given discovered by Maxam and Gilbert, and Sanger although were very powerful and popular but were not high throughput and economic. Therefore, it was necessary to develop new economic and high-throughput methods that can sequence the biodiversity consequently providing better insights of their possible function. New methods were developed and commercialized by Roche Life Sciences, Thermo Fisher Scientific, Illumina, and Applied Biosystems. These methods generally referred to as next-generation sequencing methods have revolutionized the DNA sequencing. Many sequencing platforms employing NGS have been developed including pyrosequencing, Ion Torrent technology, Illumina/Solexa platform, and SOLiD (Sequencing by Oligonucleotide Ligation and Detection). Further optimization has led to innovative third and fourth-generation platforms as single molecule real-time (SMRT) sequencing by PacBio, nanopore sequencing, etc. As a consequence there is a sharp increase in the number of genomes being published and other genome-based studies since 2012. This has made it easy even to imagine of sequencing the genomes of individuals. Furthermore, scientists are now looking for third-generation sequencers that may be significantly different from the sequencers that are currently available.

The increasing use of silver (Ag) nanoparticles (NPs) in daily-life applications, electronics, or catalysis calls for green and cost-efficient synthetic methods. Ag NPs are used especially in biomedicine because of their antibacterial, antifungal, or anticancer properties. Chemical synthesis allows tuning the particle morphology, size, and crystallinity, but requires toxic and hazardous chemicals. Bioinspired synthetic protocols have shown promise to minimize environmental impact, but biological protocols for the synthesis of Ag NPs lack control on the morphology and crystallinity. This review briefly compiles the chemical synthesis of Ag NPs and contrasts it with "green" protocols based on lessons learnt from chemical synthesis. The synthesis of Ag NPs with different plant extracts and the associated phytomolecules, their chemical and biological effects, and their effect on particle synthesis are described and put into perspective to improve green protocols. The surface functionalization of Ag NPs by phytomolecules and the mechanisms of their biomedical applications are summarized.

Streptococcus mitis from the oral cavity causes endocarditis and other systemic infections. Rising resistance against traditional antibiotics amongst oral bacteria further aggravates the problem. Therefore, antimicrobial and antibiofilm activities of zinc oxide and titanium dioxide nanoparticles (NPs) synthesized and characterized during this study against S. mitis ATCC 6249 and Ora-20 were evaluated in search of alternative antimicrobial agents. ZnO and TiO2-NPs exhibited an average size of 35 and 13 nm, respectively. The IC50 values of ZnO and TiO2-NPs against S. mitis ATCC 6249 were 37 and 77 µg ml(-1), respectively, while the IC50 values against S. mitis Ora-20 isolate were 31 and 53 µg ml(-1), respectively. Live and dead staining, biofilm formation on the surface of polystyrene plates, and extracellular polysaccharide production show the same pattern. Exposure to these nanoparticles also shows an increase (26-83 %) in super oxide dismutase (SOD) activity. Three genes, namely bapA1, sodA, and gtfB like genes from these bacteria were identified and sequenced for quantitative real-time PCR analysis. An increase in sodA gene (1.4- to 2.4-folds) levels and a decrease in gtfB gene (0.5- to 0.9-folds) levels in both bacteria following exposure to ZnO and TiO2-NPs were observed. Results presented in this study verify that ZnO-NPs and TiO2-NPs can control the growth and biofilm formation activities of these strains at very low concentration and hence can be used as alternative antimicrobial agents for oral hygiene.

Recently, nanoscale (