Isolation and in vitro culture of zygotes and central cells of Oryza sativa L

 All component cells of the embryo-sac before and after fertilization in rice were isolated by manual microdissection under conditions either free of enzymes or combined with a short pulse of enzymatic treatment.In general, the frequency of isolated unfertilized or fertilized egg cells or central cells reached 15-40%. Various component cells of the embryo-sac after isolation were distinguished by their own morphological characteristics. The isolated cells were cultured in a microchamber and fed with dividing rice suspension cells. Both unfertilized and fertilized egg cells and central cells were induced to divide. Among them only the fertilized egg cells (the zygotes) developed into proembryo-like multicellular structures. The frequency of the first zygotic division and the frequency of multicellular structures were higher using the non-enzymatic method than using the enzymatic one.

An improved microculture method for diagnosis of cutaneous leishmaniasis

This study evaluated the performance of three diagnostic methods for cutaneous leishmaniasis (CL). Patients who came to the Health Center Laboratory of Gonbad-e-Qabus in Golestan Province, Iran, were enrolled in the study. Skin scraping smear, improved microculture (IMC) and polymerase chain reaction (PCR) were performed. A total of 303 subjects were recruited, among whom 273 subjects fulfilled the criteria for CL. Sensitivity and specificity were 88.8 % (95 % CI = 84.2-92.2 %) and 100.0 % for smears, 98.4 % (95 % CI = 96.1-99.1 %) and 100.0 % for IMC, both of them 100.0 % for PCR. Although, PCR was relatively more sensitive than the IMC, the high correlation (agreement = 96 %, Kappa = 0.82) between IMC and PCR along with the advantages of simplicity, rapidity, adequate sensitivity and as a needle free method, offers the IMC as a valuable alternative diagnostic method for PCR in diagnosis of CL.

A Convenient and Sensitive kDNA-PCR for Screening of Leishmania infantum Latent Infection Among Blood Donors in a Highly Endemic Focus, Northwestern Iran

BACKGROUND

Recent global evidences showed that asymptomatic blood donor carriers of Leishmania infection will appear as a threat for blood transfusions recipients in endemic areas. As yet, there is no appropriate diagnostic procedure for detecting infection of blood donors in blood banks.

SUBJECTS AND METHODS

The present study was aimed to apply various current diagnostic tests among blood donors in an endemic area of visceral leishmaniasis (VL), Ardabil Province, northwestern Iran. Blood samples were gathered from 860 blood donors in endemic areas of the province between 2017 and 2018, at eight blood donation centers. These samples was assessed using microculture, serological (DAT and rK39-ICT) and molecular based (conventional kDNA-PCR and HRM-PCR) tests.

RESULTS

Of 860 eligible donors, 24 (2.8%) were seropositive for VL by DAT, and 388 (45%) were positive by kDNA-PCR. Moreover, 19 (19/860) were positive for both of them. Out of 19 subjects, 5.3% (1/19) was positive by rK39-ICT, 10.5% (2/19), and 79% (15/19) were detected positive in microculture and HRM-PCR methods, respectively. Nineteen donors were followed up for 2 years, of which 16 (84.2%) had a serological conversion, and 4 (21%) were positive by kDNA-PCR. The sensitivity of kDNA-PCR, and HRM-PCR procedures in detecting Leishmania parasite was found to be 98.7%, and 79%, respectively.

CONCLUSIONS

Our findings justify the use of kDNA-PCR as a convenient and sensitive tool for screening subjects with leishmanial latent infection in blood banks at least in endemic regions. In these areas, however, a PCR-based test should be used to validate Leishmania infection among seropositive donors.

Characterization of neuronal viability and network activity under microfluidic flow

BACKGROUND

Microfluidics technology has the potential to allow precise control of the temporal and spatial aspects of solute concentration, making it highly relevant for the study of volume transmission mechanisms in neural tissue. However, full utilization of this technology depends on understanding how microfluidic flow at the rates needed for rapid solution exchange affects neuronal viability and network activity.

NEW METHOD

We designed a tape-based pressurized microfluidic flow system that is simple to fabricate and can be attached to commercial microelectrode arrays. The device is multi-layered, allowing the inclusion of a porous polycarbonate membrane to isolate neuronal cultures from shear forces while maintaining diffusive exchange of solutes. We used this system to investigate how flow affected survival and spiking patterns of cultured hippocampal neurons.

RESULTS

Viability and network activity of the cultures were reduced in proportion to flow rate. However, shear reduction measures did not improve survival or spiking activity; media conditioning in conjunction with culture age proved to be the critical factors for network stability. Diffusion simulations indicate that dilution of a small molecule accounts for the deleterious effects of flow on neuronal cultures.

COMPARISON WITH EXISTING METHODS

This work establishes the experimental conditions for real time measurement of network activity during rapid solution exchange, using multi-layered chambers with reversible bonding that allow for reuse of microelectrode arrays.

CONCLUSIONS

With correct media conditioning, the microfluidic flow system allows drug delivery on a subsecond timescale without disruption of network activity or viability, enabling in vitro reproduction of volume transmission mechanisms.

Screening for Oily Yeasts Able to Convert Hydrolysates from Biomass to Biofuels While Maintaining Industrial Process Relevance

Research has recently intensified to discover new oleaginous yeast strains able to function quickly and efficiently in low-cost lignocellulosic hydrolysates to produce high-quality lipids for use in biodiesel and chemicals. Detailed techniques are given here for ranking candidate yeast strains based on conversion of hydrolysate sugars to lipids and then optimizing cultivation conditions for best performers in a 96-well aerobic microcultivation format. A full battery of assays applicable to high throughput of small-volume samples are described for efficiently evaluating cell biomass production, lipid accumulation, fatty acid composition, and sugar utilization. Original data is additionally presented on the validation of the microtechnique for GC analysis of lipid composition in yeast since this application involved modification of a previously published assay for microalgae.

Optimization of an autaptic culture system for studying cholinergic synapses in sympathetic ganglia

An autaptic synapse (or 'autapse') is a functional connection between a neuron and itself, commonly used in studying the molecular mechanisms underlying synaptic transmission and plasticity in central neurons. Most previous studies on autonomic synaptic functions have relied on spontaneous connections among neurons in mass cultures. However, growing evidence supports the utility of microcultures cultivating autaptic neurons for examining cholinergic transmission within sympathetic ganglia. Despite these advancements, standardized protocols for culturing autaptic sympathetic neurons have yet to be established. Drawing on historical literature, this study delineates optimal experimental conditions to efficiently and reliably produce cholinergic synapses in sympathetic neurons within a short time frame. Our research emphasizes five key factors: (i) the generation of uniformly sized microislands of growth permissive substrates; (ii) the addition of nerve growth factor, ciliary neurotrophic factor (CNTF), and serum to the culture medium; (iii) independence from specific serum and neuronal medium types; (iv) the reciprocal roles of CNTF and glial cells; and (v) the promotion of cholinergic synaptogenesis in SCG neurons through indirect glia co-cultures, rather than direct glial feeder layer cultures. In conclusion, glia-free monocultures of SCG neurons are relatively simple to prepare and yield robust and reliable synaptic currents. This makes them an effective model system for straightforwardly addressing fundamental questions about neurogenic mechanisms involved in cholinergic synaptic transmission in autonomic ganglia. Furthermore, autaptic culture experiments could eventually be implemented to investigate the roles of functional neuron-satellite glia units in regulating cholinergic functions under physiological and pathological conditions.