growth curves
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2023 ◽  
Vol 83 ◽  
M. Hussain ◽  
I. Liaqat ◽  
N. M. Ali ◽  
N. Arshad ◽  
U. Hanif ◽  

Abstract Pheretima posthuma (Vaillant, 1868), a native earthworm of Pakistan and Southeast Asia, has wide utilization in vermicomposting and bioremediation process. In this study, P. posthuma coelomic fluid (PCF) and body paste (PBP) was evaluated as antibacterial agent against ampicillin (AMP) resistant five Gram positive and four Gram negative clinical isolates. The antibacterial effect of different doses (i.e. 25-100 µg/ml) of PCF and PBP along with AMP and azithromycin (AZM) (negative and positive controls, respectively) were observed through disc diffusion and micro-dilution methods. All nine clinical isolates were noticed as AMP resistant and AZM sensitive. Antibacterial effects of PCF and PBP were dose dependent and zone of inhibitions (ZI) against all clinical isolates were between 23.4 ± 0.92 to 0 ± 00 mm. The sensitivity profile of PCF and PBP against clinical isolates was noticed as 44.44 and 55.56%, respectively. Both PCF and PBP showed bacteriostatic (BTS) action against S. aureus, S. pyogenes, K. pneumonia, N. gonorrhoeae. Moreover, the cumulative BTS potential of PCF and PBP against all isolates was 66.67 and 55.56%, respectively. The MICs of PCF and PBP were ranged from 50-200 µg/ml against selected isolates. The bacterial growth curves indicated that PCF and PBP inhibited the growth of all isolates at their specific MIC concentrations. However, PBP has better antibacterial potential compared to PCF against selected isolates. Therefore, it is concluded that both PCF and PBP of P. posthuma possess antibacterial and BTS potential against ampicillin resistant clinical isolates. This organism might be considered as a second choice of antibacterial agents and can further be utilized in pharmaceutical industries for novel drug manufacturing by prospecting bioactive potential agents.

2023 ◽  
Vol 83 ◽  
T. H. Nguyen ◽  
C. X. Nguyen ◽  
M. Q. Luu ◽  
A. T. Nguyen ◽  
D. H. Bui ◽  

Abstract Ri chicken is the most popular backyard chicken breed in Vietnam, but little is known about the growth curve of this breed. This study compared the performances of models with three parameters (Gompertz, Brody, and Logistic) and models containing four parameters (Richards, Bridges, and Janoschek) for describing the growth of Ri chicken. The bodyweight of Ri chicken was recorded weekly from week 1 to week 19. Growth models were fitted using minpack.lm package in R software and Akaike’s information criterion (AIC), Bayesian information criterion (BIC), and root mean square error (RMSE) were used for model comparison. Based on these criteria, the models having four parameters showed better performance than the ones with three parameters, and the Richards model was the best one for males and females. The lowest and highest value of asymmetric weights (α) were obtained by Bridges and Brody models for each of sexes, respectively. Age and weight estimated by the Richard model were 8.46 and 7.51 weeks and 696.88 and 487.58 g for males and for females, respectively. Differences in the growth curves were observed between males and female chicken. Overall, the results suggested using the Richards model for describing the growth curve of Ri chickens. Further studies on the genetics and genomics of the obtained growth parameters are required before using them for the genetic improvement of Ri chickens.

2022 ◽  
Vol 12 ◽  
Jörg S. Deutzmann ◽  
Grace Callander ◽  
Wenyu Gu ◽  
Albert L. Müller ◽  
Alexandra L. McCully ◽  

Optical density (OD) measurement is the gold standard to estimate microbial cell density in aqueous systems. Recording microbial growth curves is essential to assess substrate utilization, gauge sensitivity to inhibitors or toxins, or determine the perfect sampling point. Manual sampling for cuvette-photometer-based measurements can cause disturbances and impact growth, especially for strictly anaerobic or thermophilic microbes. For slow growing microbes, manual sampling can cause data gaps that complicate analysis. Online OD measurement systems provide a solution, but are often expensive and ill-suited for applications such as monitoring microbial growth in custom or larger anaerobic vessels. Furthermore, growth measurements of thermophilic cultures are limited by the heat sensitivity of complex electronics. Here, we present two simple, low-cost, self-assembled photometers—a “TubeOD” for online measurement of anaerobic and thermophilic cultures in Hungate tubes and a “ClampOD” that can be attached to virtually any transparent growth vessel. Both OD-meters can be calibrated in minutes. We detail the manufacturing and calibration procedure and demonstrate continuous acquisition of high quality cell density data of a variety of microbes, including strict anaerobes, a thermophile, and gas-utilizing strains in various glassware. When calibrated and operated within their detection limits (ca. 0.3–90% of the photosensor voltage range), these self-build OD-meters can be used for continuous measurement of microbial growth in a variety of applications, thereby, simplifying and enhancing everyday lab operations.

2022 ◽  
Nikolai Nikolaevich Kovalev ◽  
Svetlana Yevgenyevna Leskova ◽  
Yevgeny Valeryevich Mikheev ◽  
Yulia Mikhailovna Pozdnyakova ◽  
Roman Vladimirovich Esipenko

The use of gibberellic acid as a stimulator of microalgae growth has beensubstantiatedexperimentally.This research aimed to assess the effect of exposure to a wide range of gibberellic acid concentrations on the growth dynamics ofthe microalgaTetraselmissuecicain an enrichment culture. The duration of the experiments was 14 days. It has been shown that gibberellic acid,atconcentrations of 0.39–3.20× 10−8M, stimulates algaegrowth. In this research, the exposure to gibberellic acid at concentrations of 0.39–3.20 × 10−8M was accompanied by a variation in the pattern of growth curves: the maximum number of cells was recorded on day seven of the experiment. A higher concentration of the phytohormone (3.84 × 10−8М) inhibited the increase inculture density. The growth of theT. suecicaculture in the control group was 332%;the growth of the culture exposed to gibberellic acid at a concentration of 0.39 × 10−8M was1136%. The values of the specific growth rate ofT. suecicawere estimated for different periods of cultivation. On day14 of the experiment, the biochemical composition of microalgae biomass was analyzed.According to the results, gibberellic acid stimulated the accumulation of carbohydrates, proteins, and chlorophyll. Nevertheless, the phytohormone had no effect on lipidaccumulation. An assumption was made thatexposure to low concentrations of phytohormone stimulates the growth of microalgae by reducing the lag phase of growth. Keywords: gibberellic acid, microalga, cultivation, lipids, carbohydrates, proteins

2022 ◽  
Donna Jackson-Maldonado+ ◽  
Virginia A. Marchman ◽  
Philip Dale ◽  
Marta Rubio-Codina

Parent report measures have been shown to be effective, valid and cost-effective means for obtaining information about early child language development. There are several measures available in multiple languages for children below the age of 3. There has been a need for such measures for older children. This study presents the development of a Spanish version of the MacArthur-Bates Communicative Development Inventory-III for children 2 ½ to 4 years of age. A total of 571 families of monolingual Spanish-speaking children from a diverse socio-economic group were asked to fill out the parent report measure in order to obtain a norming sample. Data are presented by age and socio-economic groups that show developmental growth curves for vocabulary production and sentence complexity. Norming tables that show variability by ages are presented. Additional information is given for a General Concepts section. This study presents a new parent report instrument that can be used both clinically and for research purposes.

2022 ◽  
Vol 98 (6) ◽  
pp. 617-627
V. N. Tsarev ◽  
I. M. Makeeva ◽  
El. R. Sadchikova ◽  
M. S. Podporin ◽  
Yu. A. Trefilova ◽  

Introduction. Lactoferrin is a cationic monomeric glycoprotein produced by acinar cells and glands, present in different places of the mucous membrane in different concentrations. In connection with the development of various variants of hygienic and medicinal products for the treatment of inflammatory diseases of the oral cavity based on lactoferrin, there was a need for an objective assessment of its antibacterial and antibiofilms properties, followed by an analysis of the preservation of activity in various variants of the isolation of this protein from the substrate and storage.Aim - to improve the effectiveness of evaluating the antibacterial activity of lactoferrin and the duration of its preservation in various biological substrates containing the active substance and individual experimental batches of the manufactured drug using automatic cultivation.Materials and methods. As part of the experiment, a microbiological diagnostic technique employing a system for the automatic cultivation of microbial populations was used. A pre-prepared bacterial suspension was inoculated into the nutrient broth and the studied lactoferrin samples were added, followed by cultivation and analysis of the possible antibacterial effects of transferrin protein. To determine the sensitivity of the isolated strains, we used our own modification of the serial dilution method developed at the Department of microbiology, virology, immunology of the A.I. Yevdokimov Moscow State University of Medicine and Dentistry. The experiment was based on the programmed automatic cultivation using the RTS-1 bioreactor. The interpretation of the results was carried out by changing the optical density at a wavelength of λ = 850 nm. The study of the growth dynamics of microorganisms was carried out in several repetitions, which was reflected in the graphs of the development of bacterial populations. The assessment of the growth control of the corresponding bacterial species was reflected in the change in the optical density values, on the basis of which the curve was built. Results and discussion. According to the results of an experimental study of the growth curves of bacterial populations, statistically significant differences in the number of viable cells in different phases of the growth curves were noted, when using different lactoferrin samples. Higher activity of human recombinant lactoferrin samples was established. An analysis of growth dynamics revealed differences in the onset of the maximum reproduction and its inhibition under the influence of various aggravating factors during cultivation. The bacteriostatic effect of lactoferrin is realized through the binding of iron ions, depriving the bacteria of this microelement, causing inhibition of their development. Along with this, lactoferrin is active against certain virulence factors of microorganisms, splitting them like serine proteases, and thus prevents their penetration into human cells.Conclusion. The method used for automatic cultivation of microorganisms in the bioreactor used allows one to obtain reproducible results, is available for wide use, and can be recommended for obtaining objective, comparable, reliable information about the antimicrobial properties of various samples of the bactericidal protein lactoferrin produced by the domestic pharmaceutical industry. The studied substrate containing recombinant human lactoferrin of Russian production is characterized by high antibacterial activity that persists for 3 years as minimum.

2022 ◽  
Vol 8 ◽  
Limin S. Ding ◽  
Yuhang Zhang ◽  
Dan Wen ◽  
Jianbo Ma ◽  
Hao Yuan ◽  

SARS-CoV-2 is an emerging coronavirus threatening human health and the economy worldwide. As an RNA virus, variants emerge during the pandemic and potentially influence the efficacy of the anti-viral drugs and vaccines. Eight spike variants harboring highly recurrent mutations were selected and introduced into a replication-competent recombinant VSV in place of the original G protein (rVSV-SARS-CoV-2). The resulting mutant viruses displayed similar growth curves in vitro as the wild-type virus and could be neutralized by sera from convalescent COVID-19 patients. Several variants, especially Beta strain, showed resistance to human neutralizing monoclonal antibodies targeting the receptor-binding domain (RBD). A single dose of rVSV-SARS-CoV-2 Beta variant could elicit enhanced and broad-spectrum neutralizing antibody responses in human ACE2 knock-in mice and golden Syrian hamsters, while other mutants generated antibody levels comparable to the wild-type. Therefore, our results will be of value to the development of next-generation vaccines and therapeutic antibodies.

Lilan Sun ◽  
Lang Sun ◽  
Xue Li ◽  
Xinxin Hu ◽  
Xiukun Wang ◽  

The increasing incidence of tigecycline resistance undoubtedly constitutes a serious threat to global public health. The combination therapies had become the indispensable strategy against this threat. Herein, 11 clinical tigecycline-resistant Klebsiella pneumoniae which mainly has mutations in ramR, acrR, or macB were collected for tigecycline adjuvant screening. Interestingly, ML-7 hydrochloride (ML-7) dramatically potentiated tigecycline activity. We further picked up five analogs of ML-7 and evaluated their synergistic activities with tigecycline by using checkerboard assay. The results revealed that ML-7 showed certain synergy with tigecycline, while other analogs exerted attenuated synergistic effects among tigecycline-resistant isolates. Thus, ML-7 was selected for further investigation. The results from growth curves showed that ML-7 combined with tigecycline could completely inhibit the growth of bacteria, and the time-kill analysis revealed that the combination exhibited synergistic bactericidal activities for tigecycline-resistant isolates during 24 h. The ethidium bromide (EtBr) efflux assay demonstrated that ML-7 could inhibit the functions of efflux pump. Besides, ML-7 disrupted the proton motive force (PMF) via increasing ΔpH, which in turn lead to the inhibition of the functions of efflux pump, reduction of intracellular ATP levels, as well as accumulation of ROS. All of which promoted the death of bacteria. And further transcriptomic analysis revealed that genes related to the mechanism of ML-7 mainly enriched in ABC transporters. Taken together, these results revealed the potential of ML-7 as a novel tigecycline adjuvant to circumvent tigecycline-resistant Klebsiella pneumoniae.

2022 ◽  
Vol 22 (1) ◽  
Ya-Mei Chen ◽  
Tung-Liang Chiang ◽  
Duan-Rung Chen ◽  
Yu-Kang Tu ◽  
Hsiao-Wei Yu ◽  

Abstract Background Researchers have emphasized the importance of examining how different factors affect men’s and women’s functional status over time. To date, the literature is unclear about whether sex affects the rate of change in disability in middle to older age. Researchers have further emphasized the importance of examining how different factors affect men’s and women’s functional status over time. We examined (a) sex differences in disability trends and (b) the determinants of the rate of change in disability for men and women 50 years and older. Methods This study utilized the Taiwan Longitudinal Study on Aging Survey, a nationally representative database (four waves of survey data 1996–2007, N = 3429). We modeled and compared the differences in disability trends and the influences of determinants on trends among men and women using multiple-indicator and multiple-group latent growth curves modeling (LGCM). Equality constraints were imposed on 10 determinants across groups. Results Once disability began, women progressed toward greater disability 18% faster than men. Greater age added about 1.2 times the burden to the rate of change in disability for women than men (p < 0.001). More comorbidities also added significantly more burden to baseline disability and rate of change in disability among women than men (p < 0.001), but women benefited more from higher education levels in lower baseline disability and slower rate of change. Having a better social network was associated with lower baseline disability among women only (p < 0.05). For both men and women, physically active leisure-time activities were beneficial in lower baseline disability (pmen and women < 0.001) and rate of change in disability (pmen < 0.01; pwomen < 0.05), with no significant differences between groups. Conclusions Age may widen the sex gap in the rate of change in disability. However, both sexes benefit from participating in leisure-time activities. Promoting health literacy improves health outcomes and physical function among women.

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