27 research outputs found
Opini Komunitas Warga Sekitar Tentang Maraknya Pedagang Kaki Lima (PKL) (Studi Deskriptif Analitis Tentang Opini Komunitas Warga Sekitar Pkl – Tamansari, Kepatihan, dan Dalem Kaum – Kota Bandung)
Penelitian dengan judul “Opini komunitas warga sekitar tentang maraknya Pedagang Kaki Lima (PKL)” ini, dilakukan oleh pengajar/dosen tetap Fakultas Ilmu Komunikasi (FIK). Permasalahan penelitian adalah tentang bagaimana opini komunitas warga sekitar PKL mengenai keamanan, ketertiban, ketenangan, Kenyamanan, keindahan, kebersihan, dan keramah-tamahan (7“K”) akibat maraknya PKL. Sasaran strategis dalam penelitian ini adalah komunitas warga di sekitar lingkungan PKL Jalan Kepatihan, Dalem Kaum, dan Tamansari.Tujuan penelitian adalah untuk mengetahui, mengkaji, dan menganalisis faktor 7“K” yang dirasakan komunitas warga sekitar, akibat maraknya PKL, sehingga tanggapan yang diekspresikan mereka dapat menjadi masukan bagi Humas Pemerintah Kota Bandung dalam upaya mensosialisasikan kebijakan pemerintah tentang PKL khususnya dalam merumuskan konsep community relations berkaitan dengan 7 “K” yang dirasakan oleh komunitas warga sekitar terhadap maraknya PKL tersebut. Kesimpulan hasil penelitian ini adalah: pada umumnya opini komunitas warga sekitar terhadap maraknya PKL, dilihat dari faktor 7“K” sangatlah bervariasi di antara opini positif dan negatif, Dalam arti, untuk responden tertentu penilaiannya sangat relatif tergantung dari persepsi masing-masing dan atas dasar pengalaman masing-masing dengan para PKL tersebut. Dengan demikian tidak sepenuhnya berada pada kecenderungan tertentu yang bersifat negatif atau positif. Oleh karena itu dari opini tersebut selanjutnya dapat berkembang untuk diyakini tentang adanya kemungkinan di antara kedua belah pihak saling membina hubungan, dan pemerintah memfasilitasi hubungan tersebut dalam kebijakan-kebijakannya
RodZ modulates geometric localization of the bacterial actin MreB to regulate cell shape
Membrane protein RodZ interacts with the actin-like protein MreB, which coordinates cell-wall insertion to maintain the typical rod-like shape of E. coli cells. Here, the authors provide evidence that RodZ modulates the biophysical properties of MreB and alters the spatial organization of cell-wall growth
Conservation of conformational dynamics across prokaryotic actins.
The actin family of cytoskeletal proteins is essential to the physiology of virtually all archaea, bacteria, and eukaryotes. While X-ray crystallography and electron microscopy have revealed structural homologies among actin-family proteins, these techniques cannot probe molecular-scale conformational dynamics. Here, we use all-atom molecular dynamic simulations to reveal conserved dynamical behaviors in four prokaryotic actin homologs: MreB, FtsA, ParM, and crenactin. We demonstrate that the majority of the conformational dynamics of prokaryotic actins can be explained by treating the four subdomains as rigid bodies. MreB, ParM, and FtsA monomers exhibited nucleotide-dependent dihedral and opening angles, while crenactin monomer dynamics were nucleotide-independent. We further show that the opening angle of ParM is sensitive to a specific interaction between subdomains. Steered molecular dynamics simulations of MreB, FtsA, and crenactin dimers revealed that changes in subunit dihedral angle lead to intersubunit bending or twist, suggesting a conserved mechanism for regulating filament structure. Taken together, our results provide molecular-scale insights into the nucleotide and polymerization dependencies of the structure of prokaryotic actins, suggesting mechanisms for how these structural features are linked to their diverse functions
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How to Build a Bacterial Cell: MreB as the Foreman of E. coli Construction.
Cell shape matters across the kingdoms of life, and cells have the remarkable capacity to define and maintain specific shapes and sizes. But how are the shapes of micron-sized cells determined from the coordinated activities of nanometer-sized proteins? Here, we review general principles that have surfaced through the study of rod-shaped bacterial growth. Imaging approaches have revealed that polymers of the actin homolog MreB play a central role. MreB both senses and changes cell shape, thereby generating a self-organizing feedback system for shape maintenance. At the molecular level, structural and computational studies indicate that MreB filaments exhibit tunable mechanical properties that explain their preference for certain geometries and orientations along the cylindrical cell body. We illustrate the regulatory landscape of rod-shape formation and the connectivity between cell shape, cell growth, and other aspects of cell physiology. These discoveries provide a framework for future investigations into the architecture and construction of microbes
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AimB Is a Small Protein Regulator of Cell Size and MreB Assembly
The MreB actin-like cytoskeleton assembles into dynamic polymers that coordinate cell shape in many bacteria. In contrast to most other cytoskeleton systems, few MreB-interacting proteins have been well characterized. Here, we identify a small protein from Caulobacter crescentus, an assembly inhibitor of MreB (AimB). AimB overexpression mimics inhibition of MreB polymerization, leading to increased cell width and MreB delocalization. Furthermore, aimB appears to be essential, and its depletion results in decreased cell width and increased resistance to A22, a small-molecule inhibitor of MreB assembly. Molecular dynamics simulations suggest that AimB binds MreB at its monomer-monomer protofilament interaction cleft and that this interaction is favored for C. crescentus MreB over Escherichia coli MreB because of a closer match in the degree of opening with AimB size, suggesting coevolution of AimB with MreB conformational dynamics in C. crescentus. We support this model through functional analysis of point mutants in both AimB and MreB, photo-cross-linking studies with site-specific unnatural amino acids, and species-specific activity of AimB. Together, our findings are consistent with AimB promoting MreB dynamics by inhibiting monomer-monomer assembly interactions, representing a new mechanism for regulating actin-like polymers and the first identification of a non-toxin MreB assembly inhibitor. Because AimB has only 104 amino acids and small proteins are often poorly characterized, our work suggests the possibility of more bacterial cytoskeletal regulators to be found in this class. Thus, like FtsZ and eukaryotic actin, MreB may have a rich repertoire of regulators to tune its precise assembly and dynamics
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The inner membrane protein YhdP modulates the rate of anterograde 2 phospholipid flow in Escherichia coli
The outer membrane (OM) of Gram-negative bacteria is a selective permeability barrier that allows uptake of nutrients while simultaneously protecting the cell from harmful compounds. The basic pathways and molecular machinery responsible for transporting lipopolysaccharides (LPS), lipoproteins, and β-barrel proteins to the OM have been identified, but very little is known about phospholipid (PL) transport. To identify genes capable of affecting PL transport, we screened for genetic interactions with mlaA*, a mutant in which anterograde PL transport causes the inner membrane (IM) to shrink and eventually rupture; characterization of mlaA*-mediated lysis suggested that PL transport can occur via a high-flux diffusive flow mechanism. We found that YhdP, an IM protein involved in maintaining the OM permeability barrier, modulates the rate of PL transport during mlaA*-mediated lysis. Deletion of yhdP from mlaA* reduced the rate of IM transport to the OM by 50%, slowing shrinkage of the IM and delaying lysis. As a result, the weakened OM of ∆yhdP cells was further compromised and ruptured before the IM during mlaA*-mediated death. These findings demonstrate the existence of a high-flux diffusive pathway for PL flow in Escherichia coli that is modulated by YhdP
Response of runoff processes to temperature rise in basins with different glacier ratios in the monsoon-influenced southern Tibetan Plateau
Study region: River basins with glacier ratios ranging from 1.8% to 20.7% in the monsoon-influenced southern Tibetan Plateau. Study focus: The response of runoff processes in basins with different glacier ratios under global warming of 1.5 °C and 2 °C was explored based on SPHY (Spatial Processes in Hydrology) model and GCMs (General Circulation Models). New hydrological insights for the region: More prominent temperature and precipitation changes were observed in the monsoon-influenced southern Tibetan Plateau compared with the global averages. With increasing temperature and precipitation, the total runoff and glacier runoff of these basins showed increasing trends under global warming of 1.5 °C and 2 °C. Compared with the baseline period (1985–2014), increases were observed in the total runoff (1.7–20.6%), base flow (2.8–8.3%), glacier runoff (8.1–35.9%), and rainfall runoff (6.0–36.0%) of these basins. In contrast, snowmelt runoff decreased (−28.3% - −4.3%). Therefore, relevant management and allocation of water resources may be required. The hydrological regulation function of glaciers was found to be strongly correlated with glacier ratio. In general, the hydrological regulation function of glaciers would decrease in the future along with warming induced glacier retreat. These findings would help deepen the understanding of runoff processes on the Tibetan Plateau and other alpine regions, thus providing a scientific basis for water resources management under climate change
Response of Soil Erosion to Climate and Subsequent Vegetation Changes in a High-Mountain Basin
Soil erosion is one of the global threats to the environment. Further, climate and vegetation changes have pronounced effects on soil erosion in high-mountain areas. In this study, the revised universal soil loss equation (RUSLE) was improved by developing a method for calculating snowmelt runoff erosivity based on a simulated snowmelt runoff and the observed sediment load, using which the soil erosion rate in the upper Heihe River Basin (UHRB) was calculated. The proposed approach provides an effective method for estimating the soil erosion rate and identifying the causes for its change in high-mountain areas. The normalized difference vegetation index (NDVI) was significantly and positively correlated with both precipitation and temperature in the region and exhibited a significant increasing trend. The increase in NDVI led to a decrease in the soil erosion rate (for the annual, rainfall, and snowmelt periods), although erosive rainfall and snowmelt runoff showed increasing trends, indicating the dominating impact of vegetation cover on soil erosion. The average soil erosion rate of UHRB was 806.2 t km−2 a−1 from 1982 to 2015. On average, soil erosion during rainfall and snowmelt periods contributed to 90.67% and 9.33% of annual soil erosion, respectively. However, the resultant soil erosion rate caused by 1 mm of snowmelt runoff was about 1.9 times that caused by 1 mm erosive rainfall. Soil erosion during the snowmelt period was particularly sensitive to temperature and showed consistent responses to climate and vegetation changes in UHRB and its two tributaries. An increasing NDVI promoted by climate change and anthropogenic factors played a major role in alleviating soil erosion, and the warming exerted intense impacts on soil erosion during the snowmelt period. These findings would be helpful for proposing effective measures for soil conservation in high-mountain areas under climate and vegetation changes
Automatic reading of domestic electric meter: an intelligent device based on image processing and ZigBee/Ethernet communication
Klebsiella michiganensis transmission enhances resistance to Enterobacteriaceae gut invasion by nutrition competition
Intestinal microbiotas contain beneficial microorganisms that protect against pathogen colonization; treatment with antibiotics disrupts the microbiota and compromises colonization resistance. Here, we determine the impact of exchanging microorganisms between hosts on resilience to the colonization of invaders after antibiotic-induced dysbiosis. We assess the functional consequences of dysbiosis using a mouse model of colonization resistance against Escherichia coli. Antibiotics caused stochastic loss of members of the microbiota, but the microbiotas of co-housed mice remained more similar to each other compared with the microbiotas among singly housed animals. Strikingly, co-housed mice maintained colonization resistance after treatment with antibiotics, whereas most singly housed mice were susceptible to E. coli. The ability to retain or share the commensal Klebsiella michiganensis, a member of the Enterobacteriaceae family, was sufficient for colonization resistance after treatment with antibiotics. K. michiganensis generally outcompeted E. coli in vitro, but in vivo administration of galactitol-a nutrient that supports the growth of only E. coli-to bi-colonized gnotobiotic mice abolished the colonization-resistance capacity of K. michiganensis against E. coli, supporting the idea that nutrient competition is the primary interaction mechanism. K. michiganensis also hampered colonization of the pathogen Salmonella, prolonging host survival. Our results address functional consequences of the stochastic effects of microbiota perturbations, whereby microbial transmission through host interactions can facilitate reacquisition of beneficial commensals, minimizing the negative impact of antibiotics.info:eu-repo/semantics/publishedVersio