Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

of antibiotics, whether there was an explicit note in the medical chart in which the physician diagnosed a true bacteremia, and the Centers for Disease Control surveillance criteria for primary bloodstream infection. Agreement between same-strain bacteremia and each definition was examined, based on the assumption that most true infections should be the result of a single strain. The study sample consisted of 42 patients and 106 isolates. Nineteen of the 42 bacteremias (45%) were the same strain. Classification of bacteremias as same-strain correlated poorly with all three clinical assessments (range of percentage agreement, 50%-57%; range of kappa statistic, 0.01-0.15). There were both false-positive and false-negative errors. Patients with three or more positive blood cultures were more likely to have same-strain bacteremia than those with only two positive cultures (11/15 [73%] vs 8/27 [30%], P=.006). Pulsed-field gel electrophoresis was more discriminating than AP PCR (percentage agreement, 83%; kappa, 0.67). The authors concluded that molecular typing correlated poorly with clinical criteria for true bacteremia, suggesting either that true bacteremias are frequently the result of multiple strains or that the commonly used clinical criteria are not accurate for distinguishing contamination from true bacteremia. Vancomycin treatment of clinically defined coagulase-negative staphylococcal bacteremia may frequently be unnecessary. FROM: Seo SK, Venkataraman L, DeGirolami PC, Samore MH. Molecular typing of coagulase-negative staphylococci from blood cultures does not correlate with clinical criteria for true bacteremia. Am J Med 2000;109:697-704.

/pdf/nasal-carriage-as-a-source-of-staphylococcus-aureus-40zkf0m446.pdf

Nasal Carriage as a Source of Staphylococcus aureus Bacteremia

Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested to be one of the possible alternatives for achieving sustainable weed management. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/residues can also give desirable benefits. Not only the terrestrial weeds, even allelopathy can be suitably manipulated for the management of aquatic weeds. The allelochemicals present in the higher plants as well as in the microbes can be directly used for weed management on the pattern of herbicides. Their bioefficacy can be enhanced by structural changes or the synthesis of chemical analogues based on them. Further, in order to enhance the potential of allelopathic crops, several improvements can be made with the use of biotechnology or genomics and proteomics. In this context either the production of allelochemicals can be enhanced or the transgenics with foreign genes encoding for a particular weed-suppressing allelochemical could be produced. In the former, both conventional breeding and molecular genetical techniques are useful. However, with conventional breeding being slow and difficult, more emphasis is laid on the use of modern techniques such as molecular markers and the selection aided by them. Although the progress in this regard is slow, nevertheless some promising results are coming and more are expected in future. This review attempts to discuss all these aspects of allelopathy for the sustainable management of weeds.

Allelopathic Interactions and Allelochemicals: New Possibilities for Sustainable Weed Management

There has been many recent studies on the use of microbial antagonists to control diseases incited by soilborne and airborne plant pathogenic bacteria and fungi, in an attempt to replace existing methods of chemical control and avoid extensive use of fungicides, which often lead to resistance in plant pathogens. In agriculture, plant growth-promoting and biocontrol microorganisms have emerged as safe alternatives to chemical pesticides. Streptomyces spp. and their metabolites may have great potential as excellent agents for controlling various fungal and bacterial phytopathogens. Streptomycetes belong to the rhizosoil microbial communities and are efficient colonizers of plant tissues, from roots to the aerial parts. They are active producers of antibiotics and volatile organic compounds, both in soil and in planta, and this feature is helpful for identifying active antagonists of plant pathogens and can be used in several cropping systems as biocontrol agents. Additionally, their ability to promote plant growth has been demonstrated in a number of crops, thus inspiring the wide application of streptomycetes as biofertilizers to increase plant productivity. The present review highlights Streptomyces spp.-mediated functional traits, such as enhancement of plant growth and biocontrol of phytopathogens.

https://www.mdpi.com/1422-0067/19/4/952/pdf

Plant Growth Promoting and Biocontrol Activity of Streptomyces spp. as Endophytes.

Natural products represent a vast repository of materials and compounds with evolved biological activity, including phytotoxicity. Some of these compounds can be used directly or as templates for herbicides. The molecular target sites of these compounds are often unique. Strategies for the discovery of these materials and compounds are outlined. Numerous examples of individual phytotoxins and crude preparations with weed management potential are provided. An example of research to find a natural product solution of a unique pest management problem (blue-green algae in aquaculture) is described. Finally, the problems associated with natural products for pest control are discussed.

https://www.jstor.org/stable/pdfplus/4046356.pdf

Invited Paper: Chemicals from nature for weed management

As a result of the increasing environmental and health-related problems caused by the synthetic agrochemicals currently used, suitable and non-hazardous innovative alternatives are being sought. Antagonism and allelopathy, both in nature and in agro-ecosystems, have attracted these researchers' attention, with the main goal of using these phenomena in the biological control of weeds. This article presents a review on the use and efficacy of microbial secondary metabolites which have potential as natural herbicides, either directly or as templates for bio-rational eco-friendly agrochemicals (allelochemicals). Their merits as alternatives to synthetic chemicals and biological control agents have been highlighted for an holistic approach in integrated pest/weed management.

Microbial metabolites as eco-friendly agrochemicals for the next millennium

The emerging and reemerging forms of fungal infections encountered in the course of allogeneic bone marrow transplantations, cancer therapy, and organ transplants have necessitated the discovery of antifungal compounds with enhanced efficacy and better compatibility. A very limited number of antifungal compounds are in practice against the various forms of topical and systemic fungal infections. The trends of new antifungals being introduced into the market have remained insignificant while resistance towards the introduced drug has apparently increased, specifically in patients undergoing long-term treatment. Considering the immense potential of natural microbial products for the isolation and screening of novel antibiotics for different pharmaceutical applications as an alternative source has remained largely unexplored. Endophytes are one such microbial community that resides inside all plants without showing any symptoms with the promise of producing diverse bioactive molecules and novel metabolites which have application in medicine, agriculture, and industrial set ups. This review substantially covers the antifungal compounds, including volatile organic compounds, isolated from fungal endophytes of medicinal plants during 2013–2018. Some of the methods for the activation of silent biosynthetic genes are also covered. As such, the compounds described here possess diverse configurations which can be a step towards the development of new antifungal agents directly or precursor molecules after the required modification.

https://www.mdpi.com/2309-608X/4/3/77/pdf/1

Endophytic Fungi: A Source of Potential Antifungal Compounds

Nowadays polylactic acid (PLA) is widely used in orthopedics surgeries as implants material due to well mechanical characterization and biomedical properties. But the PLA implants suffer from slow degradation rate when it is used in real-life scenario. In the present research work, the PLA specimens using additive manufacturing technique are fabricated and further assessed for mechanical characterization and its degradation behavior with different parameters. The change in weight of scaffolds was measured using digital weight measure, and pH value was measured using pH meter. Morphology and elemental composition of PLA scaffolds were characterized by SEM and EDS, respectively, while compressive strength is measured by the universal testing machine. Apatite formation and biocompatible nature of fabricated scaffolds were analyzed by in vitro simulated body fluid study. The outcomes of characterization exposed that scaffold with 60% infill percentage had maximum porosity, which is beneficial for the apatite formation and osseointegration. The average change in compressive strength was measured as 49.79 MPa after 14 days and 46.11 MPa after 28 days, whereas the average change in pH value was measured as 5.67 and 5.27 after 14 and 28 days of incubation period, respectively. The degradation rate of specimen 3 was 27.92% less than that of specimen 1, 35.69% less than that of specimen 5, and 87.98% more than that of specimen 9. This study concludes the positive effect of process parameters on degradation rate and biocompatible behavior of PLA implants.

Synthesis, characterization, and bioactivity investigation of biomimetic biodegradable PLA scaffold fabricated by fused filament fabrication process

Genus Muscodor came into existence with the discovery of Muscodor albus, a sterile endophytic fungus that produces a medley of volatile organic moieties possessing strong antimicrobial activity. The current paper reports Muscodor tigerii as a novel endophytic fungus from the stem internal tissue of Cinnamomum camphora growing in the Tiger Hill area of Darjeeling, West Bengal, India. M. tigerii exhibited distinct morphological, molecular and physiological features than previously reported Muscodor species. The fungus possesses all the morphological features described till date in genus Muscodor making it remarkably unique. The strong fruity smell of the fungus is attributed to 22 volatile organic compounds (VOCs), predominantly 4-Octadecylmorpholine, 1-Tetradecanamine,N,N-dimethyl and 1,2-Benzenedicarboxylic acid, mono(2-ethylhexyl) ester. The in vitro VOC stress assay completely suppressed the growth of Alternaria alternata and Cercospora beticola while growth of other fungal species was inhibited in a range of 10 %-70 %. The growth of Candida albicans in the presence of VOC was reduced by 50 %-65 % while in bacteria 50 %-80 % reduction in growth was observed. Thus, M. tigerii stands as a potential candidate to be further developed into a biocontrol agent.

Muscodor tigerii sp. nov.-Volatile antibiotic producing endophytic fungus from the Northeastern Himalayas

Glycyrrhiza glabra Linn. is an age-old plant used in traditional medicine across the globe for its ethnopharmacological values to cure varieties of ailments from simple cough to hepatitis to more complex like SARS and cancer. The present paper is an effort to highlight the role of a few major constituents of this plant, which have multifaceted pharmacological actions and could be used as templates for designing new pharmacophores using modern chemical and bioanalytical tools.

/pdf/glycyrrhiza-glabra-medicine-over-the-millennium-1mczgr04co.pdf

Sanjai Saxena

Papers

Microbial metabolites as eco-friendly agrochemicals for the next millennium

Endophytic Fungi: A Source of Potential Antifungal Compounds

Synthesis, characterization, and bioactivity investigation of biomimetic biodegradable PLA scaffold fabricated by fused filament fabrication process

Muscodor tigerii sp. nov.-Volatile antibiotic producing endophytic fungus from the Northeastern Himalayas

Glycyrrhiza glabra : Medicine over the millennium