Science

The essential oil extracted by hydrodistillation from the flowering twigs of Stevia rebaudiana Bertoni (Asteraceae) was fractioned by chromatography. Forty-three constituents were characterized with the help of GC, GC-MS and other spectroscopic techniques. The essential oil was found to be a complex mixture of mono- and sesqui-terpenes. The cytotoxicity of the essential oil and its fractions was evaluated by sulforhodamine B (SRB) based assay against two cancer cell types viz. C-6 (rat glioma cells) and CHOK1 (Chinese hamster ovary cells). The essential oil and its fractions showed promising cytotoxicity against both cell lines. The highest activity (95.6+/-0.6%) was show by the essential oil on the C-6 cell line at a concentration of 400 microg/mL, which was comparable with that of the standard drug vinblastin.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/25026731/

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Stevia, a zero-calorie sugar substitute, is recognized as safe by the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). In vitro and in vivo studies showed that stevia has antiglycemic action and antioxidant effects in adipose tissue and the vascular wall, reduces blood pressure levels and hepatic steatosis, stabilizes the atherosclerotic plaque, and ameliorates liver and kidney damage. The metabolism of steviol glycosides is dependent upon gut microbiota, which breaks down glycosides into steviol that can be absorbed by the host. In this review, we elucidated the effects of stevia's consumption on the host's gut microbiota. Due to the lack of randomized clinical trials in humans, we included in vitro using certain microbial strains and in vivo in laboratory animal studies. Results indicated that stevia consumption has a potential benefit on the microbiome's alpha diversity. Alterations in the colonic microenvironment may depend on the amount and frequency of stevia intake, as well as on the simultaneous consumption of other dietary components. The anti-inflammatory properties of stevioside were confirmed in vitro by decreasing TNF-α, IL-1β, IL-6 synthesis and inhibiting of NF-κB transcription factor, and in vivo by inhibiting NF-κB and MAPK in laboratory animals.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/35456796/

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Steviol glycosides (SGs) in Stevia (Stevia rebaudiana Bertoni) leaves are important due to their high sweetness and low calorific value. The yield of SGs is dependent on fertilization regimes, but the relationship between nitrogen (N) administration and SGs synthesis is still unclear. In this study, we investigate the effects of N rates on SGs production through hydroponic and plot experiments. The SGs yield was not significantly changed by N fertilization, but leaf SGs concentrations were significantly reduced due to the "dilution effect". Additionally, N addition decreased leaf carbon (C)/N ratio and soluble sugar concentration, accompanied with the inhibited phosphoenolpyruvate carboxylase and L-phenylalanine ammonia_lyase activities. A significant positive correlation between leaf SGs concentrations, C/N ratio and soluble sugar concentration was observed. Overall, we suggest that N-driven Stevia growth negatively affects SGs concentrations. The leaf C/N ratio and soluble sugar changes indicated the occurrence of metabolic reprogramming.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/31195254/

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Plant growth and secondary metabolism are commonly regulated by external cues such as light, temperature and water availability. In this study, the influences of low and high temperatures, dehydration, photoperiods, and different growing stages on the changes of steviol glycosides (SGs) contents and transcription levels of fifteen genes involved in SGs biosynthesis of Stevia rebaudiana Bertoni were examined using HPLC and RT-PCR. The observations showed that the transcript levels of all the fifteen genes were maximum under 25 °C treatment, and the transcription of SrDXS, SrDXR, SrMCT, SrCMK, SrMDS, SrHDS, SrHDR, SrIDI, SrGGDPS, SrCPPS1, SrUGT85C2 and SrUGT76G1 were restrained both in low temperature (15 °C) and high temperature (35 °C). Most genes in SGs biosynthesis pathway exhibited down-regulation in dehydration. To elucidate the effect of photoperiods, the plants were treated by different simulated photoperiods (8 L/16 D, 1 0L/14 D, 14 L/10 D and 16 L/8 D), but no significant transcription changes were observed. In the study of growing stages, there were evident changes of SGs contents, and the transcript levels of all the fifteen genes were minimal in fast growing period, and exhibited evident increase both in flower-bud appearing stage and flowering stage. The obtained results strongly suggest that the effect of environmental cues on steviol glycosides contents and transcription of corresponding biosynthetic genes in S. rebaudiana is significant. It is worth to study deeply.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/25500454/

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More than 60 naturally occurring steviol glycosides in the Stevia rebaudiana Bertoni plant share a similar molecular structure with an aglycone steviol backbone conjugated with β- and α-glycosidic bonds to different sugar moieties. These glycosides are naturally produced in different quantities within the stevia leaf. Certain minor glycosides with superior sensory attributes, such as Reb D and Reb M, are found less than 0.1% in traditional stevia leaves. New technologies can now produce better tasting steviol glycosides by using enzymatic conversion of stevioside and Reb A, which are abundant in stevia leaf. Several regulatory authorities recently evaluated steviol glycosides produced by enzymatic conversion of stevia leaf extract and approved them safe for human consumption. Steviol glycosides undergo microbial hydrolysis in the colon to generate steviol, which is absorbed and metabolized into steviol glucuronide, and excreted primarily via human's urine. Previous studies have shown the hydrolysis of highly purified individual steviol glycosides extracted from stevia leaf are converted to steviol in the presence of colonic microbiota of adults. Since colonic microbiota of children may be different from adults, this study investigates the metabolic fate in the colonic microbiota of adults and children of the minor steviol glycosides produced by extraction and enzymatic conversion of major steviol glycosides from stevia leaf. Several in vitro incubation tests were conducted in human fecal homogenates collected from adult and pediatric populations with steviol glycoside test samples comprised of a complex stevia leaf extract, a blend of minor glycosides isolated from stevia extract and two mixtures of steviol glycosides produced by enzymatic conversion of Reb A to larger molecules by attaching glucose units via β- or α-glycosidic bonds. Results from these studies clearly demonstrate steviol glycosides produced by extraction from stevia leaf, or enzymatic conversion of stevia leaf extract, share the same metabolic fate in the human gut microbiota from adults and children. Considering a common metabolite structure and a shared metabolic fate in all ages, safety data for individual steviol glycosides can be used to support safety of all steviol glycosides produced by extraction and enzymatic conversion of stevia leaf extract.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/32745585/

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Stevia rebaudiana Bertoni is a valuable plant whose products are increasingly used in medicine, pharmacy and the food industry. This necessitates the use of biotechnological approaches for its mass propagation. Establishing optimal conditions for in vitro cultivation is essential for obtaining high biomass and secondary metabolites production. A large number of articles considering the role of plant growth regulators and other additives in the culture medium in the growth and development of Stevia are available in the literature. However, there are no summarized data about the use of nanoparticles in Stevia tissue cultures. Therefore, this review also includes the research conducted so far on the effect of nanoparticles on Stevia micropropagation. Furthermore, the influence of different elicitors on secondary metabolite production and antioxidant activity of in vitro-cultivated Stevia plants have been discussed. By referring to the collected literature, we concluded that biotechnological approaches applied to S. rebaudiana cultivation might improve the agronomic traits of plants and steviol glycosides production.
#Stevia #kombucha #ikombucha_ro #ikombucha
https://pubmed.ncbi.nlm.nih.gov/36616282/

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Scientists have created a power generator that uses atmospheric humidity and polyoxometalates to produce continuous electricity, offering a sustainable way to utilize low-value energy.

Lung cancer is the leading cause of cancer-related deaths in the United States. Some tumors are extremely small and hide deep within lung tissue, making it difficult for surgeons to reach them. To address this challenge, UNC –Chapel Hill and Vanderbilt University researchers have been working on an extremely bendy but sturdy robot capable of traversing lung tissue.

Researchers publicly call out theory that they say is not well supported by science, but that gets undue attention.

A letter, signed by 124 scholars and posted online last week1, has caused an uproar in the consciousness research community. It claims that a prominent theory describing what makes someone or something conscious — called the integrated information theory (IIT) — should be labelled “pseudoscience”. Since its publication on 15 September in the preprint repository PsyArXiv, the letter has some researchers arguing over the label and others worried it will increase polarization in a field that has grappled with issues of credibility in the past.

Ancient timber preserved in a riverbed suggests humans were building wooden structures 500,000 years ago.

For a phenomenon that is so deeply engrained in the public consciousness, the scientific evidence regarding what has been called "beer goggles" is surprisingly inconsistent. The term refers to finding people more attractive after drinking alcohol, and there is a wealth of scientific evidence both for and against its existence.

Paleontologists at University College Cork (UCC) in Ireland have discovered X-ray evidence of proteins in fossil feathers that sheds new light on feather evolution.

this is driving me pretty mad, i've got hygrometers, digital and analog all reading wildly different percentages, and would like to calibrate them, read up on the salt test, where you take salt make it damp stick it in a plastic bag and after +8 hrs the internal humidity of the bag should be exactly 75%. for anyone that's familiar with calibrating hygrometers, should 2 TBSP table salt plus 1/2 TBSP water in a small monkey dish, in a gallon bag work? or is it too much water for the salt, too big of a bag, too much or too little time. did the test overnight on 4 different hygrometers for 12 hours, took them out of the bag, and now after 30 minutes to equalize to room temp, are not only once again wildly off, but the lowest is reading what I would imagine to be 10 percentage points of how humid the room "feels". maddening. thanks.

Researchers inoculated rapeseed plants with a species of fungus that is known for its ability to combat pest insects. Utilizing the relationship between beneficial fungi and crop plants may introduce a new era of agriculture where the plant resilience is improved and the ecological footprint of trad

Scientists Discover Source of Mysterious Earth Tremors | Scitech Daily
#science #Earthquakes #Fracking #Geophysics #Seismology #Geology

The bright lights of big cities could be causing an evolutionary adaptation for smaller eyes in some birds, a new study indicates.

RNA for the first time recovered from an extinct species A new study shows the isolation and sequencing of more than a century-old RNA molecules from a Tasmanian tiger specimen preserved at room temperature in a museum collection. This resulted in the reconstruction of skin and skeletal muscle transcriptomes from an extinct species for the first time. The researchers note that their findings have relevant implications for international efforts to resurrect extinct species, including both the Tasmanian tiger and the woolly mammoth, as well as for studying pandemic RNA viruses.

There has been a real race among scientists to create a technology that enables easy protein sequencing. Professor of Chemical Biology Giovanni Maglia of the University of Groningen has now found the missing piece in the puzzle: a way to transport a protein through a nanopore, which allows sequencing of proteins in a simple, handheld device.

K?

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FAU researchers provide the first quantified observations of the “birth” of purpose in human infants, as they recognize their causal powers and transition from spontaneous to intentional behavior.

Seeing lots of spam and ads for illegal drugs, etc. Are the moderators on vacay?

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Recent research dives deep into the impact of autism on marital bonds. Over a 30-year span, parents of children with autism showcased a 36% divorce rate, with specific peak periods. Surprisingly, families of verbally adept autistic teenagers faced unique stressors, leading to higher divorce rates. The strength and resilience of these families remind us of the unique challenges they face.

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Autism—or the formal term, Autism Spectrum Disorder (ASD)—is a developmental difference presenting through symptoms on a spectrum concerning social interaction, communication and behavior. What’s really interesting about this disorder is that every single person with autism experiences it differently. They may have amazing special abilities in certain parts but may be lacking in other areas which makes it difficult to have a standard definition of autism. Visualize a rainbow of hues, each one di

New Research Reveals That Butterflies and Moths Share Ancient “Blocks” of DNA | SciTech Daily
#science #ecology #evolution #genetics #DNA #entomology #bugs #insects #butterflies #moths