Real-Time Vital Mineralization Detection and Quantification during In Vitro Osteoblast Differentiation

Background

In vitro studies of osteoblasts traditionally use Alizarin Red as a golden standard for the detection and quantification of mineralization, which is a marker of osteoblast differentiation. However, this method presents a number of drawbacks, including the need to fix cells, which prevents additional measurements. Years ago, Calcein Green was proposed as an alternative to Alizarin Red, with the advantage to be directly detectable in live cells. However, the protocol was still time-consuming, and it never managed to replace Alizarin Red. Now, with more efficient imaging systems, we present a protocol using Calcein Green which provides significant advantages.

Results

The osteoblast mineralization was efficiently detected and accurately quantified in real time at any desired time point across the entire differentiation period, with a minimum time expenditure.

Conclusions

The combination of Calcein Green and the real-time imaging station IncuCyte ZOOM can efficiently replace the Alizarin Red method, and allows very accurate and time-saving assessment of the level and the dynamics of matrix mineralization.

Electronic supplementary material

The online version of this article (10.1186/s12575-018-0079-4) contains supplementary material, which is available to authorized users.

A time-lapse photography method for monitoring salmon (Oncorhynchus spp.) passage and abundance in streams

Accurately estimating population sizes is often a critical component of fisheries research and management. Although there is a growing appreciation of the importance of small-scale salmon population dynamics to the stability of salmon stock-complexes, our understanding of these populations is constrained by a lack of efficient and cost-effective monitoring tools for streams. Weirs are expensive, labor intensive, and can disrupt natural fish movements. While conventional video systems avoid some of these shortcomings, they are expensive and require excessive amounts of labor to review footage for data collection. Here, we present a novel method for quantifying salmon in small streams (<15 m wide, <1 m deep) that uses both time-lapse photography and video in a model-based double sampling scheme. This method produces an escapement estimate nearly as accurate as a video-only approach, but with substantially less labor, money, and effort. It requires servicing only every 14 days, detects salmon 24 h/day, is inexpensive, and produces escapement estimates with confidence intervals. In addition to escapement estimation, we present a method for estimating in-stream salmon abundance across time, data needed by researchers interested in predator--prey interactions or nutrient subsidies. We combined daily salmon passage estimates with stream specific estimates of daily mortality developed using previously published data. To demonstrate proof of concept for these methods, we present results from two streams in southwest Kodiak Island, Alaska in which high densities of sockeye salmon spawn.

Time-lapse angiography of the ocular fundus: a new video-angiography

Background

Ocular fundus angiography is an indispensable component of the tests utilized for fundus diseases. Dynamic angiography results can provide additional information; however, many difficulties remain. In this study, we introduce a modified method, time-lapse angiography (TLA), to dynamically present imaging results.

Methods

TLA, combining time-lapse photography and fundus angiography (using Heidelberg retina angiography II, Germany), includes pre-photographing and post- photosynthesis and ultimately produces a video that is approximately 15 s in length.

Results

Four typical videos in the article showed the characteristics of TLA, including a short and rapid but continuous and integral presentation, highly valid information, high definition, etc.

Conclusions

TLA is beneficial for the diagnosis of diseases and the assessment of progression and is convenient for peer communication, patient interpretation, and student education. The application of time-lapse photography in ocular fundus angiography is a monumental and innovative attempt.

Analysis of Plant Root Gravitropism

Gravity is a powerful element in shaping plant development, with gravitropism, the oriented growth response of plant organs to the direction of gravity, leading to each plant's characteristic form both above and below ground. Despite being conceptually simple to follow, monitoring a plant's directional growth responses can become complex as variation arises from both internal developmental cues as well as effects of the environment. In this protocol, we discuss approaches to gravitropism assays, focusing on automated analyses of root responses. For Arabidopsis, we recommend a simple 90° rotation using seedlings that are 5-8 days old. If images are taken at regular intervals and the environmental metadata is recorded during both seedling development and gravitropic assay, these data can be used to reveal quantitative kinetic patterns at distinct stages of the assay. The use of software that analyzes root system parameters and stores this data in the RSML format opens up the possibility for a host of root parameters to be extracted to characterize growth of the primary root and a range of lateral root phenotypes.

Assessing Gravitropic Responses in Arabidopsis

Arabidopsis thaliana was the first higher organism to have its genome sequenced and is now widely regarded as the model dicot. Like all plants, Arabidopsis develops distinct growth patterns in response to different environmental stimuli. This can be seen in the gravitropic response of roots. Methods to investigate this particular tropism are presented here. First, we describe a high-throughput time-lapse photographic analysis of root growth and curvature response to gravistimulation allowing the quantification of gravitropic kinetics and growth rate at high temporal resolution. Second, we present a protocol that allows a quantitative evaluation of gravitropic sensitivity using a homemade 2D clinostat. Together, these approaches allow an initial comparative analysis of the key phenomena associated with root gravitropism between different genotypes and/or accessions.