Correlation analysis of macular microvascular structure and macular pigment opticaldensity in retinal vein occlusion / 中华眼底病杂志

Objective:To observe the changes of macular microvascular structure and macular pigment density (MPOD) in eyes with macular edema (ME) secondary to retinal vein occlusion (RVO), and preliminarily analyze their correlation.Methods:A prospective clinical study. A total of 62 eyes of 62 patients with monocular RVO secondary ME (RVO-ME) diagnosed in the Ophthalmology Hospital of Xi'an No.1 Hospital from July 2020 to May 2021 were included in this study. There were 33 males with 33 eyes, 29 females with 29 eyes. The age was 58.30±12.15 years. The course of disease from the onset of symptoms to medical treatment was 12.29±7.65 days. All patients underwent best corrected visual acuity (BCVA), optical coherence tomography angiography (OCTA) and MPOD test. BCVA examination was performed using a standard logarithmic visual acuity chart, which was converted to logarithm of minimum angle of resolution (logMAR). The vascular density (VD), vascular skeletal density (SD), foveal avascular area (FAZ) and central macular thickness (CMT) of the superficial retinal capillary plexus (SCP) in the range of 3 mm×3 mm in the macular area of bilateral eyes were measured by OCTA. MPOD was measured by heterochromatic scintillation photometry. Bilateral eyes passed examination in 37 cases. The eyes of 25 patients failed to pass the test. The changes of macular VD, SD, FAZ area, CMT and MPOD between the affected eyes and the contralateral eyes were compared. The MPOD of the affected eye and the contralateral eye was compared by paired t test. FAZ area, CMT, VD, SD, and logMAR BCVA were tested by paired Wilcoxon signed rank sum test. Spearman rank correlation test was used to analyze the correlation between macular blood flow density (VD, SD) and foveal morphology (FAZ area, CMT) with logMAR BCVA and MPOD. Results:Compared with contralateral eyes, VD ( Z=-5.981) and SD ( Z=-6.021) were decreased, FAZ area ( Z=-2.598) and CMT ( Z=-6.206) were increased, and the differences were statistically significant ( P<0.05). In 37 patients who passed MPOD test in bilateral eyes, the MPOD value of the affected eye was lower than that of the contralateral eye, and the difference was statistically significant ( t=-2.930, P<0.05). Compared with the affected eye which failed to pass the MPOD detection, macular VD ( Z=-2.807) and SD ( Z=-2.460) were increased, FAZ area ( Z=-4.297) and CMT ( Z=-3.796) were decreased in the affected eye which passed the MPOD test, and the differences were statistically significant ( P<0.05). Correlation analysis showed that logMAR BCVA in the affected eye was negatively correlated with macular VD and SD ( r=-0.298, -0.461; P<0.05), which was positively correlated with FAZ area and CMT ( r=0.487, 0.789; P<0.05). MPOD in the affected eye was negatively correlated with logMAR BCVA ( r=-0.344, P<0.05). MPOD in the contralateral eye was positively correlated with CMT ( r=0.358, P<0.05). Conclusions:The VD and SD of macular SCP are decreased, FAZ area is enlarged, CMT is thickened, and MPOD is decreased in RVO-ME eyes. MPOD is negatively correlated with logMAR BCVA.

Integrated optical density analysis of the immunohistochemical expression of the progesterone receptor in the uterine endometrium of prepubertal araucana sheep / Análisis por densidad óptica integrada de la expresión inmunohistoquímica del receptor de progesterona en el endometrio uterino de ovejas prepúberes de raza araucana

SUMMARY: Progesterone receptors are expressed in the reproductive organs of adult sheep, where they regulate morphofunctional and reproductive development. However, various studies have shown the presence of these receptors in the uterus of prepubertal females. It is not clear what role these receptors have at this level of development in uterine tissue. Therefore, it is relevant as a first step in the investigation, to determine the expression and histological distribution of the progesterone receptor in prepubertal sheep in order to determine possible functions at this level of reproductive development. Immunohistochemical analysis allows visualizing the specific presence of a protein in the cellular and histological context, however, the results displayed through digital images are qualitative data and subject to the observer's criteria. In this work, a quantitative analysis method of immunohistochemical expression of the progesterone receptor in ovine endometrium is presented, using digital analysis of images, by means of integrated optical density of digital photographs of histological sections processed with immunohistochemical methods. The results show the possibility of quantitatively evaluating the expression of progesterone receptors in the endometrial stroma and prepubertal endometrial glands by applying the integrated optical density analysis of digital images.

RESUMEN: Los receptores de progesterona se expresan en los órganos reproductores de ovejas adultas, donde regulan el desarrollo morfofuncional y reproductivo. Sin embargo, diversos estudios han demostrado la presencia de estos receptores en útero de hembras prepúberes. No está claro, el papel que estos receptores tienen en este nivel de desarrollo en tejido uterino. Por lo que, es relevante como primer paso en la investigación, determinar la expresión y distribución histológica del receptor de progesterona en ovejas prepúberes con el fin determinar posibles funciones en este nivel de desarrollo reproductivo. El análisis inmuno- histoquímico permite visualizar la presencia específica de una proteína en el contexto celular e histológico, sin embargo, los resultados visualizados a través de imágenes digitales, son datos cualitativos y sujeto al criterio del observador. En este trabajo se presenta un método de análisis cuantitativo de expresión inmunohistoquímica del receptor de progesterona en endometrio ovino, utilizando análisis digital de imágenes, mediante densidad óptica integrada de fotografías digitales de cortes histológicos procesados con métodos inmunohistoquímicos. Los resultados muestran la posibilidad de evaluar cuantitativamente la expresión de los receptores de progesterona en el estroma endometrial y las glándulas endometriales prepúberes aplicando el análisis de densidad óptica integrado de imágenes digitales.

Crecimiento y metabolismo de Fischerella TB22 en medio de cultivo BG11 / Growth and metabolism of Fischerella TB22 in BG110 culture medium

Los microorganismos fijadores de nitrógeno de vida libre, abarcan una gama morfológica que va desde los organismos unicelulares como las bacterias y algunas cianobacterias, hasta multicelulares, filamentosas, por ello es importante conocer cómo se comportan y se puede saber haciendo una curva de crecimiento microbiano. Para este estudio se prepararon 4 fotobioreactores de columna burbujeada con inoculo de Fischerella TB22, se pusieron en aireación constante con 12 horas luz y 12 horas obscuridad durante 40 días con diferentes tratamientos de ajuste de volumen del medio de cultivo y ajuste del pH. El objetivo de este trabajo fue evaluar el crecimiento en biomasa por peso seco, densidad óptica, pH y amonio de Fischerella sp. en medio de cultivo BG110 durante 12 días. Las variables que se midieron de la curva de crecimiento de las cianobacterias, siguieron el patrón de una curva típica de crecimiento microbiano. (AU)

Free-living nitrogen-fixing microorganisms cover a morphological range that goes from unicellular organisms such as bacteria and some cyanobacteria, to multicellular, filamentous, therefore it is important to know how they behave and can be known by makinga microbial growth curve. For this study, 4 bubbled column photobioreactors with Fischerella TB22inoculum were prepared, they were placed in constant aeration with 12 hours of light and 12 hours of darkness for 40 days with different treatments of volumeadjustment of the culture medium and pH adjustment. The objective of this work was to evaluate the biomass growth by dry weight, optical density, pH, and ammonia of Fischerella sp. in the BG110 culture medium for 12 days. The variables that were measured from the growth curve of cyanobacteria followed the pattern of a typical microbial growth curve. (AU)

An observational study of macular optical density in patients with obstructive sleep apnea hypopnea syndrome / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the change of macular pigment optical density(MPOD)in the patients of obstructive sleep apnea-hypopnea syndrome(OSAHS). <p>METHODS: Totally 70 OSAHS patients as observation group and 32 healthy subjects as control group with their right eyes were enrolled from Chongqing Emergency Medical Center during January to December of 2019. All the subjects used Visucam 200 to measure the mean/max MPOD. <p>RESULTS: Both mean/max MPOD(0.0916±0.0149, 0.2675±0.0419Log unit)of OSAHS group are significantly lower than the control group(0.1193±0.0159, 0.3235±0.0400Log unit, <i>P</i><0.001).There are significant difference of mean/max MPOD between mild(<i>n</i>=12)/moderate(<i>n</i>=17)/severe(<i>n</i>=41)groups divided by AHI(<i>P</i><0.001). The increasing severity of OSAHS lead to lower mean/max MPOD.Furthermore there is negative correlation between mean/max MPOD and AHI(<i>r</i>=-0.685, -0.492; <i>P</i><0.001).<p>CONCLUSION: Our study results suggest that the mean/max MPOD were reduced in the patients of OSAHS. Moreover, the decreased degree of mean/max MPOD is positively related to the severity of OSAHS. It shows that the MPOD of OSAHS have already changed before they feel the significant syndrome. The reducing of MPOD may cause dysfunction of macular and finally rise up to macular disease.

A randomized controlled trial on the effect of Lutein Supplementation on Macular Pigment Optical Density and Macular Function in Pseudophakic Patients

Objective@#To evaluate the efficacy of oral lutein supplementation on macular pigment optical density (MPOD) levels and macular function in pseudophakic eyes that underwent phacoemulsification. @*Methods@#This was a prospective, randomized, parallel-arm, single-masked study comparing oral lutein supplement 20 mg/tablet (Lutax 20) with non-supplementation in pseudophakic eyes. We assessed MPOD, low-luminance deficit (LLD), visual recovery time (VRT) using photostress test, and adverse events. One hundred twenty-eight (128) eyes were enrolled and randomized 1:1 to active treatment (lutein supplementation) or no treatment (no supplementation). The supplementation period was 12 weeks and patients were assessed every 4 weeks over a period of 16 weeks.@*Results@#Sixty-four (64) eyes in each group completed the study. A significant increase in MPOD (p<0.001) was observed in the lutein supplemented group, from 0.36 DU at baseline to 0.55 DU at week 12, with a mean increase of 6.32 ± 1.72% per 4 weeks of supplementation compared with a mean MPOD decrease rate of 0.63 ± 0.48% in the non-supplementation group. A significant reduction in LLD was observed in the lutein-treated group, from LogMAR 0.063 at baseline to LogMAR 0.023 at Week 12 (p=0.003). VRT was also significantly shorter in the treatment from a baseline of 83.06 to 68.80 seconds at Week 12 (p<0.001).@*Conclusion@#Lutein supplementation (20 mg/tablet; Lutax 20) demonstrated a significant degree of MPOD augmentation, and reductions in LLD and VRT among patients who underwent phacoemulsification with lens implantation.

Macular Pigment Optical Density in the Korean Population: a Cross Sectional Study

50 years) showed lower MPOD than younger (30–49 years) subjects. But, in the healthy population, the estimated MPOD values exhibited a decreasing trend with age, but there were no significant differences according to age, after excluding patients with AMD. MPOD was significantly lower in patients with AMD than in aged healthy controls. Furthermore, hypertension, dyslipidemia, and smoking were identified as risk factors for AMD.CONCLUSION: MPOD measured with MPSII® reflects the MP density in healthy individuals and patients with dry AMD. Aging was not significantly associated with low MPOD in healthy population, but the presence of dry AMD was significantly associated with low MPOD. Then, low MPOD may be a risk factor for development of dry AMD. Furthermore, routine screening with MPS II® for ages 50 and older is thought to help detect early low MPOD and identify individuals who should take supplements.

Characterization of biofilm formation by Escherichia coli: An in vitro study

Objective: The purpose of the present study was to characterize the effects of medium, optical density (OD), andincubation time on biofilm formation by Escherichia coli in brain heart infusion (BHI) and Luria-Bertani broth(LB). Methods: The main procedure involved fixing the bacterial film with 95% ethanol, staining with 0.1% crystalviolet, releasing the bound dye with 33% glacial acetic acid, and measuring the OD of the solution at 570 nm using amicroplate reader. Results: It was found that 3 and 5 days of incubation are critical for biofilm formation as indicatedby the OD values of 0.55–0.35 and 0.70–0.39 in BHI and LB, respectively, at OD 0.05. Similarly, pattern in resultswas noted for OD 0.1 in both media BHI and LB. Conclusion: It is confirmed that 3 days (72 h) are required forobtaining effective biofilm formation in both BHI and LB at 37°C at OD 0.05 and 0.1.

Correlations among macular pigment optical density, central macular thickness and body mass index / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To determine the relationship among the macular pigment optical density(MPOD), central macular thickness and body mass index(BMI).<p>METHODS: This is a comparative cross-sectional study performed in a single institution. Totally 210 volunteers who met the inclusion criteria were included in this study. The subject's MPOD was measured using Macula Pigment Screener II(MPS II, by Electron Technology). Central macular thickness was measured with Spectral Domain Cirrus Optical Coherence Tomography(OCT), Cirrus(Model 4000, Carl Zeiss Meditec). The information of both MPOD and OCT from both eyes were recorded. The data was analysed using Microsoft© Excel \〖Version 15.12.3(150724)℃2015 Microsoft\〗, SPSS(IBM© SPSS© Statistics Version 2.2), and R(version 3.2.1; R Core Team 2015).<p>RESULTS: There was significant positive correlation between MPOD and central macular thickness(<i>r</i>=0.42, <i>P</i><0.01)and a significant negative correlation between MPOD and BMI(<i>r</i>=-0.23, <i>P</i><0.01).<p>CONCLUSION: Our study showed a significant positive correlation between MPOD and central macular thickness. Further study is needed to look at the detailed structure of the fovea and its relationship with MPOD. Our study also found a significant negative correlation between MPOD and BMI, suggesting that a reduction in BMI may increase the density of macula pigment, which can be helpful in preventing age-retinal pigment epitheliitis(ARMD).

Effects of different processing parameters of mobile DR on image quality of bedside chest radiography / 中国医学影像技术

Objective To explore the effects of different processing parameters of mobile digital radiography (DR) on image quality of bedside chest radiography.Methods Post processing parameter on 150 cases bedside DR chest image like multi frequency laplasse transform (MLT),image processing (IP) were modified,and the optimization scheme of post-processing parameters were analyzed and summarized.The paired sample t test was used to compare the difference of the imaging quality score and optical density between the default parameter group and the post processing parameter optimization group through measure the optical density of lung related area.Results Brightness,contrast and the low density in dynamic range were the main factors affecting the quality of bedside chest radiography.After modifying and optimizing the post-processing parameters,the density value of the second intercostal area was 1.68±0.04,the density value of the hilum was 0.77±0.46,the density value of pulmonary peripheral (near chest wall 1 cm and overlap with a single rib) was 0.62± 0.06,the density value of cardiac shadow was 0.44 ± 0.04,the density value of subphrenic was 0.37 ± 0.04,the lung markings was clearly showed in the lateral field of lung and was visible in the spine and heart shadow area which meet the diagnostic requirement.The density value of those parts before modify were lower than the modify value which was more closer to the reference density value,and the difference had statistically significant.The image quality score of the postprocessing parameter optimization group was 3.53 ± 0.14,which was higher than 3.02 ± 0.23 of the default parameter group,and the difference had statistically significant.Conclusion The appropriate post-processing parameters is the key to guarantee the reasonable density of lung areas image quality and the optimization post-processing parameter can improve the image quality of bedside chest radiography by the mobile DR.

Prediction of near-term breast cancer risk based on virtual optical density image / 中国医学影像技术

Objective To investigate the value of improving the prediction accuracy of near-term risk for developing breast cancer by transforming the original mammography image and fusing the different types of image features using the algorithm of machine learning.Methods The craniocaudal (CC) full-field digital mammography (FFDM) of 185 women were downloaded from the clinical database at the university of Pittsburgh medical center.Firstly,the original gray images were segmented and transformed into virtual optical density images.Then the asymmetry features were separately extracted from original gray images and virtual optical density images.Two decision tree classifiers of the first stage were trained based on the features extracted from two types of image.And the scores output from the two classifiers were used as input to train the second stage of one decision tree classifier.Leave-one-case-out method was used to validate the prediction performance of near-term risk of breast cancer.Results Using two-stage decision tree fusion method to predict breast cancer,the area under the ROC curve (AUC) was 0.9612±0.0132.And the sensitivity,specificity and prediction accuracy were 96.63％(86/89),91.67％(88/96) and 94.05％(174/185).Conclusion The features extracted from virtual optical density image have higher discriminatory power of predicting breast cancer.Fusing the two kinds of image features twice by two-stage decision tree method can help to improve the prediction accuracy of near-term risk of breast cancer.

Diagnostic value of acoustic radiation force impulse imaging in breast tumor / 重庆医学

Objective To evaluate the differentiation diagnostic value of acoustic radiation force impulse imaging (ARFI) technique to the benign and malignant breast lesions .Methods A total of 87 breast masses in 84 patients were selected and per‐formed the routine ultrasound ,virtual touch imaging(VTI) and virtual touch quantification(VTQ) examination .The shear wave ve‐locity was obtained .The average optical density of the tumor was obtained by processing the VTI images by using the image J soft‐ware .The pathological results served as the gold standard and the ROC curve was drawn .Finally ,the significance of ARFI was e‐valuated .Results All 87 pathologically verified breast tumors included 31 malignant lesions and 56 benign lesions .In malignant le‐sions ,there were 21 lesions with VTQ value≥3 .49(threshold value) and 10 lesions with VTQ value<3 .49 .In benign lesions ,there were 3 lesions with VTQ value≥3 .49 and 53 lesions with VTQ value<3 .49 .In malignant lesions ,there were 28 lesions with the mean optical density value≥202 .25(threshold value) and 3 lesions with the mean optical density value<202 .25 .In benign lesions , there were 6 lesions with the mean optical density value≥202 .25 and 50 lesions with the mean optical density value<202 .25 .There were statistically significant differences in the shear wave velocity measured by VTQ and average optical density measured by VTI between malignant and benign lesions(P=0 .000) .The sensitivity ,specificity ,positive predictive value ,negative predictive value ,ac‐curacy rate and Youden index of conventional ultrasound were 96 .8% ,67 .8% ,62 .5% ,97 .4% ,78 .2% ,0 .645 ,respectively ;which for ARFI were 93 .5% ,98 .2% ,96 .7% ,96 .5% ,96 .6% and 0 .917 ,respectively .Conclusion The ARFI is superior to the conven‐tional ultrasound in the specificity and accuracy rate in diagnosing breast tumor .

Amniotic Fluid Optical Density (AFOD) correlates with the lung maturity as well as complete maturity of the fetus A clinical observational study.

According to ACOG committee, complications of non-medically indicated (elective) deliveries between 37 and 39 weeks are faced with increased NICU admissions, transient tachypnea of thenewborn (TTN), respiratory distress syndrome (RDS), increased need for ventilator support, increased sepsis rates (suspected or proven) and higher incidence of newborn feeding problems and other transition issues. Cesarean sections done at less than 39 weeks gestation have increased risk of neonatal morbidity including respitory distress, hypoglycemia, sepsis, NICU admissions, hospitalization for more than 5 days, etc this study aims at correlating fetal maturity with amniotic fluid optic density.

Macular pigment optical density in healthy eyes of Filipino adults

Objective@#To determine the range of macular pigment optical density (MPOD) levels in healthy Filipino adults using both the MPS II and the macuscope and to investigate whether age and sex were related to inter-subject variations in MPOD.@*Methods@#This was a prospective, cross sectional study of 168 healthy Filipino patients who underwent heterochromic filter photometry to measure macular pigment levels using the MPS II and the macuscope. The MPOD levels were averaged per age group and analyzed as to variations among age and gender.@*Results@#One hundred thirty (130) and thirty-eight (38) patients underwent MPS II and macuscope testing respectively. The mean MPOD level for MPS II was 0.39(±0.16) and for macuscope 0.27(±0.07). MPOD values were similar across all age groups and gender, but they were lower when measured with the macuscope.@*Conclusions@#MPOD levels measured among healthy Filipino adults were lower with the macuscope compared to the MPS II. These differences should take into consideration the differences in apparatus and techniques of measurement.

Effect of morphine hydrochloride on growth accumulated degree hour and cephalopharyngeal skeleton of the larvae of Parasarcophaga crassipalpis under natural condition / 第二军医大学学报

Objective To explore the effect of morphine hydrochloride on growth accumulated degree hour(ADH)and cephalopharyngeal skeleton of larvae of Parasarcophaga crassipalpis under natural condition, and to prove the feasibility of predicting the postmortem interval(PMI)using ADH and the shape indexes of cephalopharyngeal skeleton. Methods The larvae of Parasarcophaga crassipalpis were fed under natural condition with rabbit meat injected with morphine hydrochloride before death. The larvae were collected at 12 h intervals until the end of the stage(the larvae did not eat any more). The larvae were fixed in boiling water and were stored as specimen. The average daily temperature during the experiment was calculated for ADH. Then the cephalopharyngeal skeletons were isolated, observed, and then photographed under light mircoscope. Finally the morphology of the cephalopharyngeal skeleton was analyzed by digital image processing system. Results (1)Under natural conditions, the ADH was changed by morphine hydrochloride to a certain degree.(2)The area of the cephalopharyngeal skeleton maintained at a certain level when entered the third instar. The sclerotized area and the average optical density of the cephalopharyngeal skeleton were increased with the increase of ADH till the end of the third instar. The ADH that the sclerotized area and the average optical density reached the maximum was obviously higher than the one that the area of the cephalopharyngeal skeleton reached the maximum. Conclusion Morphine hydrochloride can obviously change the growth ADH of larvae of Parasarcophaga crassipalpis under natural conditions. The sclerotized areas and the average optical densities of the pharyngeal sclerite of the larvae show a good linearity with ADH till the end of the third instar, which can deduce PMI when combined together.

Characterization of diesel degrading bacterial species from contaminated tropical ecosystem

The bacterial diversity in a diesel contaminated tropical soil was investigated using diesel oxidation in gradient cultures dynamics (pH and OD) of the pure cultures. The diesel dependent growths of these isolates were assessed for 15 days by monitoring the gradient fluxes in the pH and Optical density OD of the media. Results showed an increase in OD as well as fluctuations in pH values. The mean OD data obtained was 0.515- 1.187 with pH of 6.95-7.2. From the morphological and biochemical characterization and comparison with respect to the standard references, the isolates S1P1, S3P3, S2P2, S2P1,and S3P2 were presumably the members of the genera Bacillus, Pseudomonas and Mycobacterium species. From the study, it was apparent that the tropical ecosystems contained unique organisms with the ability to deal with diesel contamination.

Application of optical density studies with optical coherence tomography in ophthalmology / 中华实验眼科杂志

Optical density (OD) analysis is a kind of technology that analyzes transmitted/reflective light intensity of target tissue to learn certain characters of tissue objectively by calculating pixel values of tissue image with the help of computer technology.OD can provide 2-dimensional or 3-dimensional information and embody tiny changes of tissue systematically.It has aroused attention gradually in ophthalmology imaging in recent years.Various studies had shown diagnositc and prognostic value of OD in ocular diseases.This paper reviewed the definition of OD,application of OD in various fields,advantages and disadvantages of OD,analysis method of OD and application of OD in ophthalmology.

Measuring of Mycobacterium tuberculosis growth: a correlation of the optical measurements with colony forming units

The quantification of colony forming units (cfu), turbidity, and optical density at 600 nm (OD600) measurements were used to evaluate Mycobacterium tuberculosis growth. Turbidity and OD600 measurements displayed similar growth curves, while cfu quantification showed a continuous growth curve. We determined the cfu equivalents to McFarland and OD600 units.

Analysis the effects of film dosimetry during processing and scanning / 中华放射肿瘤学杂志

ObjectiveTo explore the effects of different flushing and scanning processing on optical density (A) responding and set up the clinic quality assurance protocol based on silver halide emulsions radiographic films.MethodsSetting different flushing temperature and choosing different batch's film and developer and fixer or fixer in the same batch with different analyzing dose were performed to analyze the effect on A value; The effect of light uniform,the stabilize work time and the noise of different scanning resolution were discussed.ResultsThe A value at the same dose level would enhance as the temperature increased;the responding curve of dose and A value with different batches of films varied a lot;the responding curve of dose and A value with different batches of films and developer and fixer solution had marked variations;the responding of dose and A with the same batches would show some low.The heterogeneity of the scanner would achieve 0.03 ; the A value of the same dose would gradually steady while the time ofscanning was more than 10 minutes:the affect of noise would increase as the dose and resolution ratio increased.ConclusionsThe best processing temperature is 29-31 ℃.Different batches of film couldn't be confounded.A new calibration must be obtained when the film dosimetry to evaluate dose distribution is used.A 5 - 10 min warm up for stabilize work and the best setting resolution/depth lever are 72 dpi/16 bit for scanning films are determined.

Mannanase production by Aspergillus niger USM F4 via solid substrate fermentation in a shallow tray using palm kernel cake as a substrate

Aims: A local fungal isolate, Aspergillus niger USM F4 produced high level of mannanase activity when cultivated in a shallow tray system (45 x 40 x 7 cm3) using palm kernel cake (PKC), an easily available cheap agricultural waste which are found abundantly in Malaysia. Methodology and Results: A range of 0.25 to 1.5 cm bed heights were investigated in tracking in the most suitable condition and maximum production of mannanase. The highest mannanase production of 918.68 U/g substrate was obtained on the fifth day of cultivation after using all the optimised cultural conditions that consisted of 400 g of PKC that equivalent to 0.50 cm of substrate thickness with the particle size of ≤ 0.5 mm, moisture content of 80% (w/w) with the addition of 2% (w/w) molasses as a carbon source and 4% (w/w) ammonium nitrate as a nitrogen source, inoculums size of 1x107 spores/ml, with once at every 24 h of mixing frequency and cultivation temperature at room temperature 30±2 °C. Conclusion, significance and impact of study: The results obtained from this study showed that a shallow tray system was suitable to be used for getting highest enzyme production in SSF. Besides using a bigger volume of substrate, the correct substrate bed height is also important.

Anti-Growth Factors Associated with Pleurotus ostreatus in a Submerged Liquid Fermentation

Aims: Previous studies had revealed that cultivation of Pleurotus ostreatus is often met with a lot of challenges ranging from environmental to biological factors which adversely affect the successful cultivation of the mushroom. Hence, a need to determine factors against mycelia colonization of substrate during mushroom’s cultivation. Methodology and Result: Conventional streak method was employed to establish the percentage inhibition as well as intercolony distance between the test organisms obtained from the infected substrate and mycelia of the mushroom during substrate colonization. The test organisms are: a fungus, Kutilakesopsis macalpineae and a bacterium, Pseudomonas tolaasii. The effect of pH and temperature on the mycelia growth of P. ostreatus was also investigated. There was a gradual increase in the percentage inhibition from 33.3 % at 24 h to 75.0 % at 168 h for K. macalpineae and 37.5 % at 24 h to 70.0 at 168 h for P. tolaasii. The inter-colony distance between the antagonists and the mushroom mycelium gradually decreased. Optical density of the mycelium growth was at its optimum at pH 4.5 and temperature of 25 °C respectively. In vitro study also showed a significant increase in the optical density from 0.855±0.03 at 24 h to 1.316±0.02 at 168 h in the absence of test antagonist as against 0.812±0.06 and 0.79±0.02 at 24 h to 1.103±0.03 and 0.902±0.03 at 168 h when K. macalpineae and P.tolaasii were used as test antagonistic respectively. Conclusion, significance and impact of study: Sterilization of substrate is essential to avoid contamination during mycelia colonization. Also, slightly acidic medium and temperature control is necessary for high yield of fruit bodies.