RbfA, a 30S ribosome-binding factor, is a multicopy suppressor of a cold-sensitive C23U mutation of the 16S rRNA and is required for efficient processing of the 16S rRNA. At 37 °C, ΔrbfA cells show ...accumulation of ribosomal subunits and 16S rRNA precursor with a significantly reduced polysome profile in comparison with wild-type cells. RbfA is also a cold-shock protein essential for Escherichia coli cells to adapt to low temperature. In this study, we examined its association with the ribosome and its role in 16S rRNA processing and ribosome profiles at low temperature. In wild-type cells, following cold shock at 15 °C, the amount of free RbfA remained largely stable, while that of its 30S subunit-associated form became several times greater than that at 37 °C and a larger fraction of total 30S subunits was detected to be RbfA-containing. In ΔrbfA cells, the pre-16S rRNA amount increased after cold shock with a concomitant reduction of the mature 16S rRNA amount and the formation of polysomes was further reduced. A closer examination revealed that 30S ribosomal subunits of ΔrbfA cells at low temperature contained primarily pre-16S rRNA and little mature 16S rRNA. Our results indicate that the cold sensitivity of ΔrbfA cells is directly related to their lack of translation initiation-capable 30S subunits containing mature 16S rRNA at low temperature. Importantly, when the C-terminal 25 residue sequence was deleted, the resulting RbfAΔ25 lost the abilities to stably associate with the 30S subunit and to suppress the dominant-negative, cold-sensitive phenotype of the C23U mutation in 16S rRNA but was able to suppress the 16S rRNA processing defect and the cold-sensitive phenotype of the ΔrbfA cells, suggesting that RbfA may interact with the 30S ribosome at more than one site or function in more than one fashion in assisting the 16S rRNA maturation at low temperature.
The São Paulo marsh antwren (
Formicivora paludicola
) is a critically endangered bird endemic to marshes in the metropolitan region of São Paulo city, Brazil. The total population is estimated to be ...around 300 individuals, distributed among 15 small (<50 ha) fragments, suggesting that loss of genetic variability may affect the long-term viability of this species. To develop genetic tools for gaining information on effective population sizes, inbreeding and gene flow between populations, we describe nine polymorphic microsatellite loci isolated from a
F. paludicola
library using next-generation sequencing. We report on levels of variation in these novel microsatellites and eight additional heterologous loci in these birds. Expected (
H
E
) and observed (
H
O
) heterozygosities averaged 0.72 and 0.70, respectively, and the number of alleles per locus ranged from 3 to 10. These loci will permit evaluation of whether artificial translocations are necessary for long-term viability of this rare bird.
This paper discussed cost-effective vision-based obstacle avoidance for Unmanned Aerial Vehicles (UAVs) operating in GPS-denied environments. The system combines the You Only Look Once (YOLO) ...architecture with stereo vision cameras (OAK-D Lite), a Raspberry Pi computer, and a flight controller unit (Pixhawk-Cube). Navigating safely through obstacles becomes challenging for UAVs in GPS-denied environments. To address this issue, the drone is configured in altitude hold mode, and the system is trained on the Common Objects in Context (COCO) dataset, enabling it to recognize objects and analyze the surrounding areas to identify free spaces. By doing so, the drone can traverse an obstacle-free path. The detected obstacle information is then utilized to generate avoidance trajectories, allowing the UAV to navigate around obstacles safely. Real-time testing of the proposed technique demonstrates its efficacy in detecting and avoiding obstacles within a threshold distance of 2 meters, with an error rate of 10%. The drone's relative speed is configured at 2 m/s during these tests.
Weed detection and removal is an essential task for a better crop yield as they compete for resources along with crops. Manual weed control methods are time-consuming and labour-intensive tasks with ...room for errors. The critical challenge is to reliably and accurately detect weed from the field. To achieve this, UAV and ground-based sensing along with deep learning, especially CNN models are used to automate crop management. CNNs based on encoder-decoder models are preferred for semantic segmentation. However, they perform poorly for low-level features such as noisy boundaries. This paper presents our work on paddy rice data collection for crop-weed segmentation and a network model based on an overcomplete representation (Kite-Net) augmented on a transfer learning-based encoder-decoder model (TernausNet) for segmenting the RGB image into three classes: crop, weed and background. The network results show convincing seg-mentation mask output on overlapping crop-weed images.
A predicted alanine to proline substitution in Stat5b that results in profound short stature, growth hormone insensitivity, and immunodeficiency represents the first natural mutation of this ...transcription factor in a human. To understand the mechanisms responsible for these pathophysiological abnormalities, we have studied the biochemical and biophysical properties of the mutant Stat5b molecule. In a cellular reconstitution model growth hormone robustly stimulated tyrosine phosphorylation and transcriptional activity of wild-type Stat5b while Stat5bA630P was minimally modified and did not promote reporter gene expression. Steady state levels of Stat5bWT were ∼3-fold higher than Stat5bA630P in cell extracts prepared with nonionic detergents. Although initial rates of biosynthesis of both proteins were similar, pulse-chase experiments established that the apparent half-life of newly synthesized soluble Stat5bA630P was <15% of Stat5bWT (3.5 h versus >24 h). Stat5bA630P accumulated in cells primarily in cytoplasmic inclusion bodies. Structural analysis of the isolated SH2 domain containing the A630P mutation showed that it resembled the wild-type SH2 segment but that it exhibited reduced thermodynamic stability and slower folding kinetics, displayed an increased hydrophobic surface, and was prone to aggregation in solution. Our results are compatible with a model in which Stat5bA630P is an inactive transcription factor by virtue of its aberrant folding and diminished solubility triggered by a misfolded SH2 domain. The potential for aggregation and formation of cytoplasmic inclusions raises the possibility that Stat5bA630P could produce additional defects through inhibition of proteasome function.
Binding of the human immunodeficiency virus (HIV-1) envelope glycoprotein gp120 to the CCR5 co-receptor reduces constraints on the metastable transmembrane subunit gp41, thereby enabling gp41 ...refolding, fusion of viral and cellular membranes, and infection. We previously isolated adapted HIV-1
JRCSF variants that more efficiently use mutant CCR5s, including CCR5(Δ18) lacking the important tyrosine sulfate-containing amino terminus. Effects of mutant CCR5 concentrations on HIV-1 infectivities were highly cooperative, implying that several may be required. However, because wild-type CCR5 efficiently mediates infections at trace concentrations that were difficult to measure accurately, analyses of its cooperativity were not feasible. New HIV-1
JRCSF variants efficiently use CCR5(HHMH), a chimera containing murine extracellular loop 2. The adapted virus induces large syncytia in cells containing either wild-type or mutant CCR5s and has multiple gp120 mutations that occurred independently in CCR5(Δ18)-adapted virus. Accordingly, these variants interchangeably use CCR5(HHMH) or CCR5(Δ18). Additional analyses strongly support a novel energetic model for allosteric proteins, implying that the adaptive mutations reduce quaternary constraints holding gp41, thus lowering the activation energy barrier for membrane fusion without affecting bonds to specific CCR5 sites. In accordance with this mechanism, highly adapted HIV-1s require only one associated CCR5(HHMH), whereas poorly adapted viruses require several. However, because they are allosteric ensembles, complexes with additional co-receptors fuse more rapidly and efficiently than minimal ones. Similarly, wild-type HIV-1
JRCSF is highly adapted to wild-type CCR5 and minimally requires one. The adaptive mutations cause resistances to diverse entry inhibitors and cluster appropriately in the gp120 trimer interface overlying gp41. We conclude that membrane fusion complexes are allosteric machines with an ensemble of compositions, and that HIV-1 adapts to entry limitations by gp120 mutations that reduce its allosteric hold on gp41. These results provide an important foundation for understanding the mechanisms that control membrane fusion and HIV-1's facile adaptability.
A Custom based IP Design for object Tracking SoC Bhat, Mahadev; R., Ujwal; Surana, Harshell ...
2020 IEEE International Conference on Electronics, Computing and Communication Technologies (CONECCT),
2020-July
Conference Proceeding
This paper involves the implementation of a hardware-software subsystem for object detection and tracking on FPGA. Here we discuss our design of a system to detect and track the object which is in ...motion. We have integrated a system with existing IPs (Intellectual Property) and designed IP to realize a system for object detection and tracking. From a video-input, the sub-system detects the object of interest and the centroid tracking algorithm is used to track the object. The objective is to reduce resource utilization in a system that uses a simple yet efficient algorithm to analyse moving object's behaviour based on video stream analysis. We have tested the system in an application for human fall detection; to identify human in the image, calculate some parameters of its silhouette shape and analyse them in real-time.
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