Plug and play: Is “directed endosymbiosis” of chloroplasts possible?

The origin of mammalian mitochondria and plant chloroplasts is thought to be endosymbiosis. Millennia ago, a bacterium related to typhus-causing bacteria may have been consumed by a proto-eukaryote and over time evolved into an organelle inside eukaryotic cells, known as a mitochondrion. The plant chloroplast is believed to have evolved in a similar fashion from cyanobacteria. This project attempted to use “directed endosymbiosis” (my term) to investigate if chloroplasts can be taken up by a land animal and continue to function. It has been shown previously that mouse fibroblasts could incorporate isolated chloroplasts when co-cultured. Photosynthetic bacteria containing chloroplasts have been successfully injected into zebrafish embryos, mammalian cells, and ischemic rodent hearts. The photosynthetic alga Chlamydomonas reinhardtii (C. reinhardtii) has also been injected into zebrafish embryos. However, to the best of my knowledge, injection of isolated chloroplasts into a land animal embryo has not been attempted before.In four pilot experiments, solutions of chloroplasts in PBS were microinjected into Drosophila melanogaster (D. melanogaster) embryos to determine if the embryos would tolerate the foreign protein. Interestingly, results indicated that a portion of the D. melanogaster embryos appeared to tolerate the injections and survive to adulthood. To determine if chloroplasts had indeed been transferred, larvae were placed under fluorescent microscopy. Chlorophyll (serving as the reporter) was found to be present in several larvae and to decline in amount over time. To investigate if the chloroplasts still functioned, a radiotracer food intake assay was performed. It was hypothesized that if the chloroplasts were generating ATP (and possibly glucose), the larvae might need less food. Results indicated a decrease in intake, however this might have occurred for other reasons.

From Lab to Farm: Elucidating the Beneficial Roles of Photosynthetic Bacteria in Sustainable Agriculture

Photosynthetic bacteria (PSB) possess versatile metabolic abilities and are widely applied in environmental bioremediation, bioenergy production and agriculture. In this review, we summarize examples of purple non-sulfur bacteria (PNSB) through biofertilization, biostimulation and biocontrol mechanisms to promote plant growth. They include improvement of nutrient acquisition, production of phytohormones, induction of immune system responses, interaction with resident microbial community. It has also been reported that PNSB can produce an endogenous 5-aminolevulinic acid (5-ALA) to alleviate abiotic stress in plants. Under biotic stress, these bacteria can trigger induced systemic resistance (ISR) of plants against pathogens. The nutrient elements in soil are significantly increased by PNSB inoculation, thus improving fertility. We share experiences of researching and developing an elite PNSB inoculant (Rhodopseudomonas palustris PS3), including strategies for screening and verifying beneficial bacteria as well as the establishment of optimal fermentation and formulation processes for commercialization. The effectiveness of PS3 inoculants for various crops under field conditions, including conventional and organic farming, is presented. We also discuss the underlying plant growth-promoting mechanisms of this bacterium from both microbial and plant viewpoints. This review improves our understanding of the application of PNSB in sustainable crop production and could inspire the development of diverse inoculants to overcome the changes in agricultural environments created by climate change.

Capsid Structure of Anabaena Cyanophage A-1(L)

A-1(L) is a freshwater cyanophage with a contractile tail that specifically infects Anabaena sp. PCC 7120, one of the model strains for molecular studies of cyanobacteria. Although isolated for half a century, its structure remains unknown, which limits our understanding on the interplay between A-1(L) and its host. Here we report the 3.35 Å cryo-EM structure of A-1(L) capsid, representing the first near-atomic resolution structure of a phage capsid with a T number of 9. The major capsid gp4 proteins assemble into 91 capsomers, including 80 hexons: 20 at the center of the facet and 60 at the facet edge, in addition to 11 identical pentons. These capsomers further assemble into the icosahedral capsid, via gradually increasing curvatures. Different from the previously reported capsids of known-structure, A-1(L) adopts a non-covalent chainmail structure of capsid stabilized by two kinds of mortise-and-tenon inter-capsomer interactions: a three-layered interface at the pseudo three-fold axis combined with the complementarity in shape and electrostatic potential around the two-fold axis. This unique capsomer construction enables A-1(L) to possess a rigid capsid, which is solely composed of the major capsid proteins with an HK97 fold. IMPORTANCE Cyanobacteria are the most abundant photosynthetic bacteria, contributing significantly to the biomass production, O 2 generation, and CO 2 consumption on our planet. Their community structure and homeostasis in natural aquatic ecosystems are largely regulated by the corresponding cyanophages. In this study, we solved the structure of cyanophage A-1(L) capsid at near-atomic resolution and revealed a unique capsid construction. This capsid structure provides the molecular details for better understanding the assembly of A-1(L), and a structural platform for future investigation and application of A-1(L) in combination with its host Anabaena sp. PCC 7120. As the first isolated freshwater cyanophage that infects the genetically tractable model cyanobacterium, A-1(L) should become an ideal template for the genetic engineering and synthetic biology studies.

Pembuatan Kompos Sampah Dapur dan Taman dengan Bantuan Aktivator EM4

<p>Pembuatan kompos dari sampah dapur dan taman dengan bantuan <em>effective microorganism</em> (EM4) dan <em>microorganism local</em> (MOL) telah dilakukan. Tujuan dari kegiatan ini adalah memanfaatkan sampah yang ada di sekitar untuk dijadikan barang yang lebih berguna. EM4 merupakan kultur campuran dari mikroorganisme yang menguntungkan yang mengandung mikroorganisme fermentasi dan sintetik yang terdiri dari bakteri Asam Laktat (<em>Lactobacillus Sp</em>), bakteri Fotosentetik (<em>Rhodopseudomonas Sp</em>), <em>Actinomycetes Sp</em>, <em>Streptomyces Sp</em> dan Yeast (ragi) dan Jamur pengurai selulose. Bahan ini membantu fermentasi bahan organik tanah menjadi senyawa organik yang mudah diserap oleh akar tanaman. Proses pembuatan kompos dilakukan dengan mencampurkan sampah dapur dan taman dengan penambahan EM4. Proses fermentasi dilakukan variasi waktu 10, 14, 21, 26 dan 32 hari. Hasil pengamatan menunjukkan bahwa semakin lama fermentasi kompos yang dihasilkan semakin baik dimana daun telah hancur berubah bentuk seperti tanah.</p><p><strong><em>Kitchen and Garden Waste Composting using EM4 Activator. </em></strong><em>Composting of kitchen and garden waste with the help of effective microorganisms (EM4) and microorganism local (MOL) has been carried out. The purpose of this activity is to use the waste to become more useful items. EM4 is a mixed culture of beneficial microorganisms. This material contains microorganisms consisting of lactic acid bacteria (Lactobacillus Sp), photosynthetic bacteria (Rhodopseudomonas Sp), Actinomycetes Sp, Streptomyces Sp, and yeast, and cellulose-decomposing fungi. This activator helps break down soil organic matter into organic compounds that are easily absorbed by plant roots. The composting was done by mixing kitchen and garden waste with the addition of EM4 and MOL. The fermentation process was carried out in variations of 10, 14, 21, 26, and 32 days. The results showed that the longer the fermentation time the better the compost was produced indicating by the leaves had crumbled into shape like the soil.</em></p>