Distinct roles of spindle checkpoint proteins in meiosis.

Gametes are produced via meiosis, a specialized cell division associated with frequent errors that cause birth defects and infertility. Uniquely in meiosis I, homologous chromosomes segregate to opposite poles, usually requiring their linkage by chiasmata, the products of crossover recombination.1 The spindle checkpoint delays cell-cycle progression until all chromosomes are properly attached to microtubules,2 but the steps leading to the capture and alignment of chromosomes on the meiosis I spindle remain poorly understood. In budding yeast meiosis I, Mad2 and Mad3BUBR1 are equally important for spindle checkpoint delay, but biorientation of homologs on the meiosis I spindle requires Mad2, but not Mad3BUBR1.3,4 Here we reveal the distinct functions of Mad2 and Mad3BUBR1 in meiosis I chromosome segregation. Mad2 promotes the prophase to metaphase I transition, while Mad3BUBR1 associates with the TOGL1 domain of Stu1CLASP, a conserved plus-end microtubule protein that is important for chromosome capture onto the spindle. Homologous chromosome pairs that are proficient in crossover formation but fail to biorient rely on Mad3BUBR1-Stu1CLASP to ensure their efficient attachment to microtubules and segregation during meiosis I. Furthermore, we show that Mad3BUBR1-Stu1CLASP are essential to rescue the segregation of mini-chromosomes lacking crossovers. Our findings define a new pathway ensuring microtubule-dependent chromosome capture and demonstrate that spindle checkpoint proteins safeguard the fidelity of chromosome segregation both by actively promoting chromosome alignment and by delaying cell-cycle progression until this has occurred.

Biosynthesis of natural aroma compounds using recombinant whole-cell tomato hydroperoxide lyase biocatalyst.

Green leaf volatiles impart characteristic aroma and flavour to a variety of natural foods due to their inherent grassy note contributed by aldehydes. Hydroperoxide lyase (HPL) is an enzyme that helps in the cleavage of fatty acid hydroperoxides to short-chain aldehydes and ω-oxo-acids. A tomato hydroperoxide lyase gene was successfully expressed in E. coli BL21 (DE3) cells and used in the subsequent production of (Z)-3-hexenal. Biochemical characterization of the HPL activity exhibited by these whole cells enabled the development of a suitable one-pot reaction process for conversion of the hydroperoxide substrate to the corresponding aldehyde, (Z)-3-hexenal, and finally to (Z)-3-hexenol, a high-value flavour and fragrance ingredient.

Evolutionary flexibility in routes to mat formation by Pseudomonas.

Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharides, the production of which is often controlled by the secondary messenger c-di-GMP. Mechanisms of mat formation have been particularly well characterized in Pseudomonas fluorescens SBW25; stimuli or mutations that increase c-di-GMP production by diguanylate cyclases (WspR, AwsR, and MwsR) result in the secretion of cellulose and mat formation. Here, we characterize and compare mat formation in two close relatives of SBW25: Pseudomonas simiae PICF7 and P. fluorescens A506. We find that PICF7-the strain more closely related to SBW25-can form mats through mutations affecting the activity of the same three diguanylate cyclases as SBW25. However, instead of cellulose, these mutations activate production of the exopolysaccharide Pel. We also provide evidence for at least two further-as yet uncharacterized-routes to mat formation by PICF7. P. fluorescens A506, while retaining the same mutational routes to mat formation as SBW25 and PICF7, preferentially forms mats by a semi-heritable mechanism that culminates in Psl and Pga over-production. Our results demonstrate a high level of evolutionary flexibility in the molecular and structural routes to mat formation, even among close relatives.

Chemotaxonomy of the ethnic antidote Aristolochia indica for aristolochic acid content: Implications of anti-phospholipase activity and genotoxicity study.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia indica L. (Aristolochiaceae) is a common medicinal plant described in many traditional medicine as well as in Ayurveda used against snakebites. Besides, the plant has also been reported traditionally against fever, rheumatic arthritis, madness, liver ailments, dyspepsia, oedema, leishmaniasis, leprosy, dysmenorrhoea, sexual diseases etc. The plant is known to contain its major bioactive constituent aristolochic acid (AA) known for its anti-snake venom, abortifacient, antimicrobial and antioxidant properties. MATERIALS AND METHODS: This present work describes a validated, fast and reproducible high performance thin layer chromatography (HPTLC) method to estimate AA from the roots of 20 chemotypes of A. indica procured from 20 diverse geographical locations from the state of West Bengal, India. Further, an evidence-based approach was adopted to investigate the reported anti-venom activity of the aqueous extracts of the A. indica roots by assessing its phospholipase A2 (PLA2) inhibitory properties since PLA2 is a major component of many snake-venoms. Finally, the cytotoxicity and genotoxicity of the aqueous root extract of the Purulia (AI 1) chemotype were assessed at various concentrations using Allium cepa root meristematic cells. RESULTS: The highest amount of AA (7643.67 µg/g) was determined in the roots of A. indica chemotype collected from Purulia district followed by the chemotypes collected from Murshidabad, Jalpaiguri and Birbhum districts (7398.34, 7345.09 and 6809.97 µg/g respectively). This study not only determines AA in the plants to select pharmacologically elite chemotypes of A. indica, but it also identifies high AA producing A. indica for further domestication and propagation of the plants for pharmacological and industrial applications. The method was validated via analyzing inter-day and intra-day precision, repeatability, reproducibility, instrumental precision, limit of detection (LOD) and limit of quantification (LOQ) and specificity. Chemotypes with high AA content exhibited superior anti-PLA2 activity by selectively inhibiting human-group PLA2. Moreover, A. indica root extract significantly inhibited mitosis in Allium cepa root tips as a potent clastogen. CONCLUSIONS: The present quick, reproducible and validated HPTLC method provides an easy tool to determine AA in natural A. indica plant populations as well as in food and dietary supplements, a potential antivenin at one hand and a possible cause of aristolochic acid nephropathy (AAN) at another. Besides, the cytotoxic and mitotoxic properties of the root extracts should be used with caution especially for oral administration.

Indian Sarsaparilla (Hemidesmus indicus): Recent progress in research on ethnobotany, phytochemistry and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Hemidesmus indicus (L.) R. Br. ex Schult. (Apocynaceae) is widely used in traditional medicine in the different parts of the Indian subcontinent due to the various biological activities attributed to its different parts, especially the roots. It has traditionally been used for treating snakebites, scorpion stings, diabetes, urinary diseases, dyspnea, menorrhagia, oligospermia, anorexia, fever, abdominal colic and pain, dysentery, diarrhea, cough, rheumatism, headache, inflammation, pyrosis, skin diseases, leprosy, sexually transmitted diseases and cancer. In Ayurveda, the plant is used in the treatment of bone-loss, low body weight, fever, stress, topical wound and psoriasis. Besides, Ayurvedic literature also depicts its use as anti-atherogenic, anti-spasmodic, memory enhancing, immunopotentiating and anti-inflammatory agents. AIM OF THE STUDY: In this review, we aim to present a comprehensive update on the ethnopharmacology, phytochemistry, specific pharmacology, and toxicology of H. indicus and its bioactive metabolites. Possible directions for future research are also outlined in brief. MATERIALS AND METHODS: Popular and widely used international databases such as PubMed, Scopus, Science Direct, Google Scholar and JSTOR were searched and traditional literature were consulted using the various search strings to retrieve a number of citations related to the ethnopharmacology, biological activity, toxicology, quality control and phytochemistry of H. indicus. All studies on the ethnobotany, phtochemistry, pharmacology, and toxicology of the plant up to 2019 were included in this review. RESULTS: H. indicus has played an important role in traditional Indian medicine (including Ayurveda) and also in European medicine. The main pharmacological properties of H. indicus include hepatoprotective, anti-cancer, anti-diabetic, antioxidant, neuroprotective, anti-ophidian, cardioprotective, nephroprotective, anti-ulcerogenic, anti-inflammatory, and antimicrobial properties. Phytochemical evaluations of the root have revealed the presence of aromatic aldehydes and their derivatives, phenolics, triterpenoids and many other compounds, some of which were attributed to its bioactivity. This review also compiles a list of Ayurvedic formulations and commercial preparations where H. indicus has been used as an active ingredient. We have included the critical assessment of all the papers cited in this manuscript based on experimental observation and other important points which reflect the loop-holes of research strategy and ambiguity in the papers reviewed in this manuscript. CONCLUSIONS: The study presents an exhaustive and updated review on the traditional, pharmacological and phytochemical aspects of H. indicus with notes on its quality control and toxicological information. Although the crude extracts of H. indicus exhibit an array of pharmacological activities, it is high time to identify more active phyto-constituents by bioactivity-guided isolation besides elucidating their structure-activity relationship. More designed investigations are needed to comprehend the multi-target network pharmacology, to clarify the molecular mode of action and to ascertain the efficacious doses of H. indicus. Moreover, H. indicus is not fully assessed on the basis of its safety and efficacy on human. We hope this review will compile and improve the existing knowledge on the potential utilization of H. indicus in complementary and alternative medicine.

A set of novel CRISPR-based integrative vectors for Saccharomyces cerevisiae.

Integrating a desired DNA sequence into yeast genomes is a widely-used genetic manipulation in the budding yeast Saccharomyces cerevisiae. The conventional integration method is to use an integrative plasmid such as pRS or YIplac series as the target DNA carrier. The nature of this method risks multiple integrations of the target DNA and the potential loss of integrated DNA during cell proliferation. In this study, we developed a novel yeast integration strategy based on the widely used CRISPR-Cas9 system and created a set of plasmids for this purpose. In this system, a plasmid bearing Cas9 and gRNA expression cassettes will induce a double-strand break (DSB) inside a biosynthesis gene such as Met15 or Lys2. Repair of the DSB will be mediated by another plasmid bearing upstream and downstream sequences of the DSB and an integration sequence in between. As a result of this repair the sequence is integrated into genome by replacing the biosynthesis gene, the disruption of which leads to a new auxotrophic genotype. The newly-generated auxotroph can serve as a traceable marker for the integration. In this study, we demonstrated that a DNA fragment up to 6.3 kb can be efficiently integrated into the Met15 or Lys2 locus using this system. This novel integration strategy can be applied to various yeasts, including natural yeast isolated from wild environments or different yeast species such as Candida albicans.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions.

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aß) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of ß-secretase and γ-secretase and Aß aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Ethnobiological treatments of neurological conditions in the Chota Nagpur Plateau, India.

ETHNOPHARMACOLOGICAL RELEVANCE: World Health Organization (WHO) has recognized the contribution of traditional medicine in the primary health care system. WHO also considers neurological disorders as one of the prime concern to the public health. Inadequate and inaccessible health facilities in the rural and underprivileged areas have forced the various tribal and non-tribal communities to use ethno-phyto and ethno-zoo therapeutics against different ailments. Chota Nagpur Plateau, India is one of the richest in India in terms of plant and animal diversity, and houses a number of indigenous communities often practising their own ethnobiological medicines. These undocumented indigenous treasure must be preserved and could be utilized in discovering lead compounds against human ailments including neuroprotective and psychoactive disorders. MATERIALS AND METHODS: A number of ethnobiological surveys were carried out during 2012-2015 in the three districts of the Bengal part of Manbhum region, Chota Nagpur Plateau via conducting open and semi-structured interviews among the traditional medicine men (65:59 males and 6 females aged between 22 and 85 years). This dataset was statistically analysed by calculating seven quantitative indexes such as use value (UV), informants' consensus factor (ICF), fidelity level (FL), relative importance (RI), cultural importance index (CII), index of agreement on remedies (IAR) and cultural agreement index (CAI). RESULTS: Sixty five traditional medicine men (TMM) reported 47 traditional formulations involving 58 plant species and 17 animal species used against 13 neurological and psychological disorders and as pro-cognitives. Fabaceae was represented by the highest number of medicinal plant species (9 species) whereas herbs (48%) and roots (28%) represented the most common plant habit and plant part, respectively. Quantitative ethnobiology revealed the frequency and coherence of ethnomedicinal reports. The plant Piper nigrum (1.35) and the animal, Spilostethus hospes (0.50) showed the highest UV. Among the ethnobotanicals, maximum RI value was noted for Hemidesmus indicus (0.91) and IAR was found to be maximum (1.00) for 8 plant species. Among the ethnozoologicals, Spilostethus hospes (0.67) displayed maximum RI value whereas Axis axis (2.32) displayed maximum CAI value. CONCLUSION: TMM possessed knowledge on preparations, dose dependence, administration, safety, possible toxicity and side effects of using traditional formulations. TMM practising age old traditional therapeutics serve as alternative medical option for the underprivileged rural ethnic people in these remote areas of the country.

Tradition in treating taboo: Folkloric medicinal wisdom of the aboriginals of Purulia district, West Bengal, India against sexual, gynaecological and related disorders.

ETHNOPHARMACOLOGICAL RELEVANCE: In order to explore the traditional medicine practised by the ethnic communities residing in the topographically and climatically challenged Purulia, an underprivileged district of West Bengal, India, a quantitative ethnobiological approach was adopted to document the folkloric use of ethnomedicinals against different sexual, gynaecological and related ailments. MATERIALS AND METHODS: Ethnobiological surveys were conducted during 2012-2015 by interviewing 82 informants or traditional healers with the help of a semi-structured questionnaire. The survey included questions on botanical and non-botanical ingredients and additives mixed with monoherbal and polyherbal formulations, vernacular names of the plants and animals, methods of preparation and administration and restrictions during medications. Additional quantitative indices such as use value, informant׳s consensus factor and fidelity level were used for data analysis. RESULTS: Twenty eight sexual and gynaecological disorders were found to be treated with 18 monoherbal and 31 polyherbal formulations consisting of a total number of 96 plant species from 86 genera and 47 families and four animal species. A variety of additives, either botanicals or non-botanicals were used with the formulations for higher efficacy and taste enhancement. Fabaceae (16 species) was found to be the most common family of medicinal plants whereas herbs (42.7%) and roots (32%) were the most common habit type and plant part used respectively. Use value, informant׳s consensus factor and fidelity level indicate frequency and coherence of citations. CONCLUSION: Age old belief on traditional medicine prevails in the studied area due to its efficacy, inexpensive price and the remoteness of tribal villages from conventional medical centres. Traditional healers had detailed knowledge of preparations, doses, methods of administration, restrictions during medications, safety and efficacy of using folkloric therapeutics against sexual and gynaecological disorders. Possible synergistic interactions among phytochemicals and additives were indicated to explain enhanced therapeutic efficacy of mixed herbal formulations.