Different Days Of Incubation Research Articles

Biodegradation of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics by floc-forming bacteria, Bacillus cereus strain SHBF2, isolated from a commercial aquafarm.

The ubiquitous proximity of the commonly used microplastic (MP) particles particularly polyethylene (PE), polypropylene (PP), and polystyrene (PS) poses a serious threat to the environment and human health globally. Biological treatment as an environment-friendly approach to counter MP pollution has recent interest when the bio-agent has beneficial functions in their ecosystem. This study aimed to utilize beneficial floc-forming bacteria Bacillus cereus SHBF2 isolated from an aquaculture farm in reducing the MP particles (PE, PP, and PS) from their environment. The bacteria were inoculated for 60 days in a medium containing MP particle as a sole carbon source. On different days of incubation (DOI), the bacterial growth analysis was monitored and the MP particles were harvested to examine their weight loss, surface changes, and alterations in chemical properties. After 60 DOI, the highest weight loss was recorded for PE, 6.87 ± 0.92%, which was further evaluated to daily reduction rate (k), 0.00118 day-1, and half-life (t1/2), 605.08 ± 138.52 days. The OD value (1.74 ± 0.008 Abs.) indicated the higher efficiency of bacteria for PP utilization, and so for the colony formation per define volume (1.04 × 1011 CFU/mL). Biofilm formation, erosions, cracks, and fragments were evident during the observation of the tested MPs using the scanning electron microscope (SEM). The formation of carbonyl and alcohol group due to the oxidation and hydrolysis by SHBF2 strain were confirmed using the Fourier transform infrared spectroscopic (FTIR) analysis. Additionally, the alterations of pH and CO2 evolution from each of the MP type ensures the bacterial activity and mineralization of the MP particles. The findings of this study have confirmed and indicated a higher degree of biodegradation for all of the selected MP particles. B. cereus SHBF2, the floc-forming bacteria used in aquaculture, has demonstrated a great potential for use as an efficient MP-degrading bacterium in the biofloc farming system in the near future to guarantee a sustainable green aquaculture production.

An Adaptive Partial Least-Squares Regression Approach for Classifying Chicken Egg Fertility by Hyperspectral Imaging.

Partial least-squares (PLS) regression is a well known chemometric method used for predictive modelling, especially in the presence of many variables. Although PLS was not initially developed as a technique for classification tasks, scientists have reportedly used this approach successfully for discrimination purposes. Whereas some non-supervised learning approaches, including, but not limited to, PCA and k-means clustering, do well in identifying/understanding grouping and clustering patterns in multidimensional data, they are limited when the end target is discrimination, making PLS a preferable alternative. Hyperspectral imaging data on a total of 672 fertilized chicken eggs, consisting of 336 white eggs and 336 brown eggs, were used in this study. Hyperspectral images in the NIR region of the 900-1700 nm wavelength range were captured prior to incubation on day 0 and on days 1-4 after incubation. Eggs were candled on incubation day 5 and broken out on day 10 to confirm fertility. While a total number of 312 and 314 eggs were found to be fertile in the brown and white egg batches, respectively, the total number of non-fertile eggs in the same set of batches was 23 and 21, respectively. Spectral information was extracted from a segmented region of interest (ROI) of each hyperspectral image and spectral transmission characteristics were obtained by averaging the spectral information. A moving-thresholding technique was implemented for discrimination based on PLS regression results on the calibration set. With true positive rates (TPRs) of up to 100% obtained at selected threshold values of between 0.50 and 0.85 and on different days of incubation, the results indicate that the proposed PLS technique can accurately discriminate between fertile and non-fertile eggs. The adaptive PLS approach was, thereby, presented as suitable for handling hyperspectral imaging-based chicken egg fertility data.

Effect of Incubation of Biochars Amendment on the Chemical Properties of Acidic Soil

Biochar is considered as universal conditioner to improve soil quality, but its effect on different soil types and rates on soil properties,bacterial community and plant growth are still unclear,particularly in the typical acid soil in southeastern Nigeria. This study was done to know the changes in soil chemical composition which could be caused by dissolution and release of nutrients from biochar in an incubation experiment. The study was conducted during rainy season in 2022 in Sobioma Agro Farms LTD using loamy sand with acidic pH (5.7). The soil were collected from the same farm. Soil was filled in separate plastic bucket with lid (2kg capacity) and treatments imposed as per the treatment details; T1: Corn Cob charred for 60 minutes @ 20 t ha-1 T2: Rice husk charred for 60 minutes @ 20 t ha -1 and T3: Poultry manure charred for 60 minutes @ 20 t ha-1. The treatments were replicated thrice, then repeated for different days of incubation (15,30 and 45days respectively). The experiment was laid out in a completely randomized design (CRD). In this study, the biochar carbon content and Total N ranges from 95.9 to 181.4 gkg" 1 and 5.2 to 8.9 gkg' 1 respectively with the highest values on rice husk biochar (Table 3). Poultry manure showed highest significant (P O.05) effect in Cu (1.61 mgkg- 1), Mn (5.26 mgkg- 1 ) and Fe (6.54 mgkg 1 ) compared to rice husk biochar and corn cob biochar (Table 4). The Cations Exchange Capacity (CEC) and base saturation (BS) increased after amendment of the acidic soil with PMB (5.51 cmolkg' 1 and 85.4% respectively).
 The results revealed that, application of different biochar increased the pH and other soil chemical properties evaluated with slight increase only in exchangeable k and Na and a decrease in exchange acidity (A l and H) of soil. During the incubation experiment changes were noticed, some nutrient element showed a continuous increase with incubation time (exchangeable Al and H in Corn cob and poultry manure biochar respectively) while some reached its maximum at the mid incubation time (CEC, BS, TN, Av.P and OM in poultry manure biochar). In some cases a decline was observed up to the mid incubation period after which an increase was observed (Exchangeable Ca and Mg in corn cob biorchar and Exchangeable k and Na in Rice husk buiochar). This work stresses the importance of biochar to soil quality improvement.

Time-related multivariate strategy for the comprehensive evaluation of microbial chemical data

IntroductionIn microbial metabolomics, the use of multivariate data analysis (MDVA) has not been comprehensively explored regarding the different techniques available and the information that each gives about the metabolome. To overcome these limitations, here we show the use of Fusarium oxysporum cultured in the presence of exogenous alkaloids as a model system to demonstrate a comprehensive strategy for metabolic profiling.Matherials and methodsF. oxysporum was harvested on different days of incubation after alkaloidal addition, and the chemical profiles were compared using LC–MS data and MDVA. We show significant innovation to evaluate the chemical production of microbes during their life cycle by utilizing the full capabilities of Partial Least Square (PLS) with microbial-specific modeling that considers incubation days, media culture availability, and growth rate in solid media.Results and DiscusscionResults showed that the treatment of the Y-data and the use of both PLS regression and discrimination (PLSr and PLS-DA) inferred complemental chemical information. PLSr revealed the metabolites that are produced/consumed during fungal growth, whereas PLS-DA focused on metabolites that are only consumed/produced at a specific period. Both regression and classificatory analysis were equally important to identify compounds that are regulated and/or selectively produced as a response to the presence of the alkaloids. Lastly, we report the annotation of analogs from the piperidine alkaloids biotransformed by F. oxysporum as a defense response to the toxic plant metabolites. These molecules do not show the antimicrobial potential of their precursors in the fungal extracts and were rapidly produced and consumed within 4 days of microbial growth.

In Vitro Evaluation of Paddy Straw Treated with Maize Spent Liquor at Varying Levels and Different Days of Incubation

In Vitro Evaluation of Paddy Straw Treated with Maize Spent Liquor at Varying Levels and Different Days of Incubation

Glycerol inoculation in eggs of young broiler breeders at different embryonic periods.

Small eggs have lesser amounts of nutrients to be used by the embryo, and the yolk glycerol is the main substrate for glycogen production, which is the main energy source in the last days of incubation. Thus, the present study aimed to assess the effect of a glycerol injection in light weight eggs at 2 different days of incubation. To this end, 336 light eggs (55.6 to 58.6g) from 32-wk-old broiler breeders were incubated. The eggs were divided into 3 treatment groups: 1 group inoculated with saline solution on the 17th d of embryonic development (E17) (control group), the second group injected with a 6mg glycerol/mL solution at E17, and the third group injected with 6mg glycerol/mL on the 18th d of incubation (E18). Incubation parameters, liver and muscle glycogen, and broilers performance at 7 d of age were evaluated. Glycerol administration in ovo did not influence hatchability, period of embryonic death or early hatching. Chicks exposed to glycerol in ovo feeding (IOF) used more yolk than birds inoculated with saline solution. Glycerol inoculation at E18 enhanced liver glycogen deposition (P = 0.001) and also improved broilers performance at 7 d, although this improvement in performance and glycogen reserves was not observed when eggs were inoculated at 17 d of incubation. Birds receiving glycerol IOF at E18 showed higher feed intake and body weight gain when compared to the control group and the group inoculated at E17. It was found that glycerol inoculation in light eggs at the 18th d of incubation contributed to raise liver glycerol levels and also to improve broilers performance at 7 d.

Hatching Performance of Indonesian Native Chicken Supplemented by L-Glutamine at Different Days of Incubation

The present study aimed to determine the hatching performance of native chicken subjected to the supplementation of L-Glutamine at different days of incubation. A total of 240 fertilized eggs native chicken eggs with an initial weight of 48.85 ± 3.3 g, were subjected to injection of glutamine on the 7th, 9th and 11th day of incubation, while the control group received no injection. A total of 1.5% glutamine was dissolved in 0.5 mL of saline solution and injected at the pointed part of the egg with the target into the albumen. Hatchability, incubation time, and chick weight at hatch were determined during the study. The hatchability of native chicken treated with an injection of glutamine amino acid on different incubation days was still lower than of the control group. However, hatches were generally more substantial in size. The incubation time of the injected chicks was longer than that of the control. Chicks from injected of glutamine on the 11th day of incubation were 12.31% heavier than controls and did not differ from injections on the day 7th and 9th of incubation. The results of this study indicated that the administration of glutamine to obtain more massive chicks at the time of hatching could be conducted on the 7th, 9th and 11th days of incubation, even with lower hatchability.

Embryological development of Salvator merianae (Squamata: Teiidae).

Here we describe the embryonic development of Salvator merianae external morphologic features, as based on observation of 28 embryos across different days of incubation at 31 ± 0.5°C. Observed developmental stages were grouped and classified into the early, middle, and late periods. The early period (Stages 3-11) is distinguished by the origin of the encephalic vesicles, sensory placodes, pharyngeal arches, and degree of body flexion and rotation. The medium period (Stages 8-15) is distinguished by limb differentiation and by cranium-facial characteristics. The late period (Stages 15-18) is determined by scale patterns, pigmentation, and embryo growth.

Short-term Influence of Organic Matter and Saline Water on Inorganic Soil Phosphorus Transformation in Barisal and Dumuria Soil Series of Bangladesh

A laboratory incubation experiment was carried out to investigate the influence of soil salinity and organic matter on inorganic phosphorus transformation with times in two different soil series such as Barisal and Dumuria located in Ganges Tidal Floodplain sites of Bangladesh. Two representative soil samples were collected from surface soil (0-15 cm) with composite sampling. The salinity and organic matter treatments were 4 dS m-1 and 5 t ha-1 (decomposed cow dung) with three replications. The treated soils were then incubated in the laboratory at field capacity moisture condition. To determine the transformation of different forms of inorganic P, sampling was done for 0, 7, 15 and 30 days. Different forms of inorganic P such as soluble and exchangeable phosphorus (SE-P), iron and aluminium bound phosphorus (Fe and Al-P), calcium bound phosphorus (Ca-P) and residual phosphorus (RE-P) were determined at different days of incubation. For Barisal soil series, the sequence of different forms of inorganic P was Ca-P>RE-P>Fe and Al-P>SE-P according to their amount. For Dumuria soil series, the sequence was Ca-P>RE-P>Fe and Al-P>SE-P, respectively. The sequence clearly indicates that the soluble and exchangeable P increases with time due to a combination of salinity and decomposed organic matter which increases the uptake of P and ultimately increases the yield. The changes were statistically significant (P < 0.001) in the case of all three soils.

Quantitative proteomics analysis of eggshell membrane proteins during chick embryonic development

The avian eggshell membrane (ESM) is a meshwork made up of highly cross-linked protein fibers and it is a scaffold upon which biomineralization of the eggshell is initiated. The ESM and associated shell participates in embryonic development by providing physical and chemical protection against pathogen invasion. We performed quantitative proteomic analysis of ESM proteins on multiple days during the three phases of embryonic development. The ESMs were stripped from both fertilized and unfertilized eggs at different days of incubation, and solubilized in a novel manner using TCEP-HCl (Tris (2-carboxyethyl) phosphine hydrochloride). The changes in ESM proteins between occurred during incubation were analyzed. Bioinformatics analysis revealed that of the 12 functional protein clusters identified, protease inhibitors were present at all phases of chick development. A group of proteins involved in calcium binding and oxygen transport were only present during the second phase. Extracellular matrix, cell adhesion proteins related to the vascularization of chorioallantoic membrane (CAM), antimicrobial proteins and proteins involved in the binding and transport of lipids were found in the second and third phases of development. These findings provide insight into the functionality and evolving nature of ESM associated proteins involved in chick embryonic development. Biological significanceThe eggshell membranes (ESMs) are a fibrous scaffold that consists of highly crosslinked collagens (types I, V but mainly X), glycoproteins and CREMPs (cysteine-rich eggshell membrane proteins). The ESMs aid in the development of the chick embryo and protect it against pathogen invasion. This biopolymeric fibrous net functions as a platform for nucleation of the calcitic eggshell which provides a primary physical barrier against bacterial ingress. Comparative proteomic analyses of proteins in the ESMs from fertilized eggs and unfertilized eggs showed changes in their levels which varied between the specific phases of chick embryogenesis across 19days of incubation. Bioinformatics characterization of these ESM proteins provides understanding of their evolving nature during chick embryonic development.

Adverse effects of aflatoxin B1 on skeletal muscle development in broiler chickens

1. Detrimental effects of in ovo administrated of aflatoxin B1 (AFB1) on the embryonic development of skeletal muscle were determined using histological methods.2. A total of 420 eggs of a Ross broiler parent stock were incubated and divided into 4 groups: (1) control, (2) 5 ng AFB1/egg group, (3) 15 ng AFB1/egg group, (4) 40 ng AFB1/egg group. Test solutions were injected via the air-sac, just prior to setting the eggs in the incubator.3. Five eggs from each group were opened on different days of incubation (11d, 13d, 17d and 21d). Developmental stages of embryos were determined according to the Hamburger–Hamilton scale and embryos were weighed. Skeletal muscle tissue samples were dissected and fixed, sectioned and stained with Crossman’s trichrome and AgNOR.4. The mean relative embryo, leg muscle and breast muscle weights of AFB1-treated groups were lower than the control group and decreased with increasing AFB1. The nucleus area and AgNOR area of the AFB1-treated groups were also lower than the control group whereas there were no significant differences in AgNOR numbers and AgNOR area/nucleus area among the treatment groups.5. It was concluded that in ovo administrated of AFB1 adversely affected the embryonic development of skeletal muscle and that affected animals might therefore be more susceptible to skeletal and muscle disorders during the growing period.

Proliferation potential of human amniotic fluid stem cells differently responds to mercury and lead exposure

There are considerable gaps in our knowledge on cell biological effects induced by the heavy metals mercury (Hg) and lead (Pb). In the present study we aimed to explore the effects of these toxicants on proliferation and cell size of primary human amniotic fluid stem (AFS) cells. Monoclonal human AFS cells were incubated with three dosages of Hg and Pb (single and combined treatment; ranging from physiological to cytotoxic concentrations) and the intracellular Hg and Pb concentrations were analyzed, respectively. At different days of incubation the effects of Hg and Pb on proliferation, cell size, apoptosis, and expression of cyclins and the cyclin-dependent kinase inhibitor p27 were investigated. Whereas we found Hg to trigger pronounced effects on proliferation of human AFS cells already at low concentrations, anti-proliferative effects of Pb could only be detected at high concentrations. Exposure to high dose of Hg induced pronounced downregulation of cyclin A confirming the anti-proliferative effects observed for Hg. Co-exposure to Hg and Pb did not cause additive effects on proliferation and size of AFS cells, and on cyclin A expression. Our here presented data provide evidence that the different toxicological effects of Pb and Hg on primary human stem cells are due to different intracellular accumulation levels of these two toxicants. These findings allow new insights into the functional consequences of Pb and Hg for mammalian stem cells and into the cell biological behavior of AFS cells in response to toxicants.

Optimization of Various Growth Media to Freshwater Microalgae for Biomass Production

In recent decades, microalgae have acquired attention from pharmaceuticals to biofuels. The growth and total chorophyll content of three economically important microalgae (Chlorella sp. NTAI01, Monoraphidium sp. NTAI02 and Scenedesmus sp. NTAI03) isolated from fresh water body in five selected culture media on different days of incubation was studied for biomass production. Biomass feedstock has reviewed great interest to be used as an alternative and renewable source of energy. All the three organisms showed varied growth pattern and total chlorophyll content in different culture media. However the growth and total chlorophyll content of Chlorella sp. NTAI01 and Monoraphidium sp. NTAI02 was optimum in Half strength Chu 10 medium. In case of Scenedesmus sp. NTAI03 the growth and total chlorophyll content was found to be significant in Bolds Basal medium. The Acidified Bolds Basal medium and BG-11 medium fairly supports the growth of all the three microalgae whereas the Modified Hoaglands medium does not support the microalgal growth. The optimized growth medium will be used for biomass production for biofuel application.

Time course for antioxidants production by Antrodia camphorata in submerged culture

The mycelia of Antrodia camphorata (Chang & Chou) Wu, Ryvarden & Chang were grown in a 50-ton fermentor for 18 days. The antioxidant properties and antioxidant components of methanolic extracts from mycelia at different days of incubation were studied. In the antioxidant activity by the conjugated diene method, EC50 value of mycelia at day 18 (1.46 mg/mL) was the best, followed by values of mycelia at days 10, 13 and 16. Reducing powers were good (＞ 0.64) at concentrations of methanolic extracts higher than 2.5 mg/mL and EC50 values were considerately low (0.40–0.53 mg/mL) for mycelia at days 7 to 16. At 0.5 mg/mL, the scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent (93.2.93.9%) and EC50 values were extremely low (0.27 mg/mL) for mycelia at days 7 to 16. The chelating effects on ferrous ions were good (58.9.92.3%) at 2.5 to 10 mg/mL. Contents of naturally occurring antioxidant components were found in the order of total phenols ＞ tocopherols ＞ ascorbic acid ＞ β-carotene. Methanolic extracts from A. camphorata red mycelia in submerged culture were good in the antioxidant properties tested, except for the scavenging effect on hydroxyl ions. More specifically, the antioxidant properties were good for mycelia at days 10 to 16.

The production of ochratoxin A by Aspergillus ochraceus in raw coffee at different equilibrium relative humidity and under alternating temperatures

Abstract The effect of alternating temperatures in the storage of coffee was studied. From the day and night values, two average temperatures (25 and 14 °C) were chosen. Such changes may occur, mainly during storage in farm barns and transport. The study was carried out under different conditions of equilibrium relative humidity (ERH): 80%, 87% and 95% for the production of ochratoxin A (OTA) by Aspergillus ochraceus in raw coffee. Temperatures were cycled at 12 h intervals. Coffee was also maintained at 25 °C under similar conditions, but without temperature cycling, at the same three values of relative humidity. Ochratoxin production was analysed after periods of 39 and 60 days after the coffee had reached the equilibrium relative humidity. The water activity and moisture content of coffee were checked and OTA production was quantified. There was little or no OTA production at 80% ERH; at 87% and 95% OTA production was high after different days of incubation. Under alternating temperatures OTA production was higher than at constant temperature, and alternating temperatures indirectly favoured OTA production due to condensation and a subsequent rapid increase in moisture content and water activity of the coffee beans.

Inhibitive Activity of Cow Urine and Cow Dung against Sclerotinia sclerotiorum of Cucumber

A study on comparative efficacy and in vitro activity of fresh cow urine and cow dung for controlling Sclerotinia rot caused by Sclerotinia sclerotiorum of cucumber was carried out following mycelial growth inhibition test, treated and untreated sclerotia with these organic matters at different days of incubation. Results showed that cow urine suppressed more effectively the mycelial growth even after 5 days of incubation in comparison to cow dung. The highest inhibition 75.9% of mycelial growth was recorded in cow dung potato dextrose agar (CUPDA) after 3 days of incubation and least 22.7% was in cow dung potato dextrose agar (CUPDA) after same days of incubation. Mycelial growth from sclerotia of S. sclerotiorum was also influenced by PDA medium mixed with cow urine and cow dung. After 6 days of incubation in CUPDA mycelial growth was only 12.9 mm whereas in CDPDA and PDA the corresponding growth at the same time were 65.8 mm and 80.0 mm. Treated sclerotia of the selected fungus with cow urine had a very effective role on suppression of mycelial growth than that of untreated one. No mycelial growth was observed up to 4 days in treated sclerotia with cow urine. After 5 days only 0.9 mm mycelial growth was measured in treated sclerotia, while in case of untreated sclerotia the growth was 42.6 mm. Application of cow urine and cow dung on growing plants inoculated with the pathogen at different concentrations also proved their inhibitive effects.

Respiration rates in eggs of the honey bee, Apis mellifera

SUMMARYRespiration rates in queen-laid and worker-laid eggs of the honey bee, Apis mellifera, were determined for the 3days of embryonic development. Respiration was quantified by measuring the amount of CO2 produced during 13 h of artificial incubation at four temperature treatments: 28°C, 31°C, 34°C, 36°C (± 0.5°C). The mean respiration rates for fertilized and unfertilized eggs from queens were 140.3 ± 4.0 and 141.2 ± 12.2 nl CO2/h/egg, respectively. The mean respiration rate for unfertilized eggs from laying workers was 125.1 ± 6.3 nl CO2/h/egg. Mortality results, as indicated by pre-emergence embryos, showed that 75% developed at 34°C compared to 37.5% at 36°C. Low temperatures of 28°C and 31°C had 12.5% and 50% embryos developing to pre-emergence stage, respectively. Respiration results showed significant differences (P = 0.05) between the different days of incubation and temperature treatments, respectively. No significant difference was observed between the fertilized eggs and unfertilized eggs from queens at the same temperature treatment. The comparison of unfertilized eggs from queens and those from laying workers also showed no significant difference. When CO2 output on all the days and temperature treatments were compared, a significant regression (R2 = 0.645) was obtained (P = 0.05).

The early chick embryo as a model to evaluate cardiovascular effects of adrenaline and nicotine

During the early stages of development, chick embryos offer a good model for vascular and circulatory studies. The present experiments were carried out with nicotine and adrenaline as validation substances, to test whether this system can be applied to evaluate functional cardiovascular effects. Nicotine was injected into the yolk before incubation and administered topically on different days of incubation. Adrenaline was injected intravascularly to evaluate functional effects (heart rate and heart arrhythmia). Mortality rates following nicotine and adrenaline application were determined. An injection of nicotine prior to incubation resulted in a dose-related increase in undeveloped chick embryos, and the topical application led to hyperaemia and haemorrhages. The body weight of the embryos was reduced due to the repeated nicotine application. After iv injection of adrenaline, heart rate increase and the occurrence of heart arrhythmia showed dose-response effects and the mortality rate was three-fold higher as compared with the controls. These results show that, following the application of adrenaline and nicotine, effects on the early chick embryo are similar to those seen in other test systems. In addition to its use in toxicology, this model is suitable for the evaluation of functional cardiovascular effects. The system does not require living animals, and uses stages of development during which the nervous system is still immature.

Developmental stage dependent toxicity of aminoguanidine on chick embryos.

Aminoguanidine (AG) sulfate was injected into the thin albumen of fertile eggs on the different days of incubation. The lethality of AG sulfate on the developing chick embryos became lower when the treatment was done at later developmental stage. When AG was injected on the 5th day of incubation, the frequency of retardation of development of the body and liver, aplasia of gallbladder and enlarged spleen was highest without high mortality compared with the other experiments. Embryos with liver damage could not hatch. 14C-AG hydrochloride injected on the 5th day of incubation easily distributed into the embryo through the yolk from the thin albumen of the injection site, but when injected on the 9th day, the agent transferred very little into the yolk and embryo. The change of transport in the eggs with development may elucidate the difference of lethality of AG. Additionally, it was confirmed using thin layer chromatography that a large part of the radioactivity in the embryo might be an unknown metabolite of AG and the substance was accumulated with extremely high concentration in the liver at 24-48 hr after the injection of AG on the 5th day of incubation. This is probably the main cause of the peculier abnormalities in the liver of chick embryos.

Ultrastructural changes in the cell cycle of cultured melanoma cells.

AbstractThe fine structure of the synchronized cultures of B16 melanoma cells at different days of incubation was studied.Our observations demonstrate that the endoplasmic reticulum first develops in the dividing cells as simple flattened smooth cisternae, which become paired or multilamellated during nuclear reconstruction and form annulate lamellae as well as typical endoplasmic reticulum with ribosome‐studded membranes in the postmitotic and interphase cells.The presence of both premelanosomes and melanosomes in dividing cells is unequivocal evidence that functionally mature melanocytes are capable of proliferation.