Reduction In Cell Population Research Articles

Hydrogen Sulfide-Releasing Carbonic Anhydrase Inhibitors Effectively Suppress Cancer Cell Growth.

This study proposes a novel therapeutic strategy for cancer management by combining the antitumor effects of hydrogen sulfide (H2S) and inhibition of carbonic anhydrases (CAs; EC 4.2.1.1), specifically isoforms IV, IX, and XII. H2S has demonstrated cytotoxicity against various cancers at high concentrations. The inhibition of tumor-associated CAs leads to lethal intracellular alkalinization and acidification of the extracellular tumor microenvironment and restores tumor responsiveness to the immune system, chemotherapy, and radiotherapy. The study proposes H2S donor-CA inhibitor (CAI) hybrids for tumor management. These compounds effectively inhibit the target CAs, release H2S consistently, and exhibit potent antitumor effects against MDA-MB-231, HCT-116, and A549 cancer cell lines. Notably, some compounds display high cytotoxicity across all investigated cell lines. Derivative 30 shows a 2-fold increase in cytotoxicity (0.93 ± 0.02 µM) under chemically induced hypoxia in HCT-116 cells. These compounds also disturb the cell cycle, leading to a reduction in cell populations in G0/G1 and S phases, with a notable increase in G2/M and Sub-G1. This disruption is correlated with induced apoptosis, with fold increases of 37.2, 24.5, and 32.9 against HCT-116 cells and 14.2, 13.1, and 19.9 against A549 cells compared to untreated cells. These findings suggest the potential of H2S releaser-CAI hybrids as effective and versatile tools in cancer treatment.

Evaluation of <i>Abrus precatorius</i> on reproductive function of male Wistar rat

Background: In recent times, attention has been shifted from synthetic drugs to the use of medicinal plants and this has greatly improved reproductive functions. Abrus precatorious plant has different parts which are used as diverse sources of naturally occurring chemicals that have a variety of therapeutic effects on the body. However, in this present study, we consolidated the reproductive property of Abrus precatorius in paroxetine-induced male reproductive dysfunction. Methods: Twenty four (24) male rats were divided into four (4) groups each containing six animals was used for this experiment following paroxetine-induced erectile dysfunction. Group one, received 1ml of distilled water, Group two received 20mg/kg of Paroxetine and 50mg/kg of sildenafil, Group three received 20mg/kg of Paroxetine and 300mg/kg of A. precatorius extract, Group four received 20mg/kg of Paroxetine and 900mg/kg of A. precatorius extract for 21 days. Results: Results from the studies reveal that there was significant decrease in the sperm motility of the rats administered with Abrus precatorius when compared with control. Interestingly, the high dose extract increased the serum testosterone levels significantly while the low dose extract significantly reduce the level of testosterone when compared with the control. Histological examination of the testes of treated rats displayed noticeable atrophy, which was characterized by disruption of the seminiferous epithelium and reduction in cell population of the Leydig cells. Conclusion: It appears that very high dose of Abrus precatorius may induce infertility by increasing serum testosterone levels.

Biosynthesis and characterization of Serratia marcescens derived silver nanoparticles: Investigating its antibacterial, anti-biofilm potency and molecular docking analysis with biofilm-associated proteins

The catastrophe of surging antibiotic resistance makes it obligatory to develop potent alternative antibacterial agents that could exhibit their action through novel approaches. Over the past few years, a shift in the ideologies has been witnessed towards synthesizing metal nanoparticles as a non-toxic formulation, the output of which could be employed to meet diverse biomedical functions. This work reports a green method of biosynthesis of silver nanoparticles (AgNPs) using the growth supernatant of Serratia marcescens as the reductant and capping agent. Though these nanoparticles are anticipated to act by varying molecular routes, their minuscule particle size is what facilitates and helps delineate its prodigious properties. The visuals from scanning electron microscopy revealed small dispersed spherical-shaped AgNPs sized between 14.7-20.8 nm. Elemental analysis through EDX ascertained the presence of Ag in good amount along with other elements contributed by the bacterial extract. The FTIR result confirmed the presence of various chemical moieties and/or biomolecules decorated on the surface of AgNPs. The S. marcescens-derived AgNPs presented excellent antibacterial activity at minimum inhibitory concentration (MIC) values ranging between 8-96 μg/mL against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Chromobacterium violaceum, Kocuria sp. and Micrococcus luteus. Besides, a significant biofilm inhibition was observed at sub-MIC levels against P. aeruginosa, S. aureus and C. violaceum. The bactericidal action of AgNPs and thereby reduction in cell population was confirmed through CFU assay and fluorescence imaging. Furthermore, molecular docking analysis done for evaluating the molecular interaction of Ag with the active site of biofilm-associated proteins of those bacteria showed effective binding of Ag to designated amino acids, thereby hinting its plausible utilization as a futuristic antimicrobial armamentarium. The entire process of biosynthesis is environmentally compatible and in future, these AgNPs could emerge as a promising alternative candidate to conventional antibiotics.

What kind of sanitation should be applied to remove <em>Brettanomyces bruxellensis</em> biofilms?

The capacity for five Brettanomyces bruxellensis strains to form biofilm on stainless steel was confirmed, and the sanitation of these biofilms was tested using a solution of lactic acid and a reference method (a solution of foaming caustic soda and peroxide at 5 %). Different responses were observed depending on the strain: lactic acid solution induced a slight reduction in cell population, while the reference method resulted in the elimination of the adhered cells for three strains, but generated VBNC states for two others. The effects of sanitation on the biofilm formed is strain-dependent.

Loss of Wwox Causes Defective Development of Cerebral Cortex with Hypomyelination in a Rat Model of Lethal Dwarfism with Epilepsy.

WW domain-containing oxidoreductase (Wwox) is a putative tumor suppressor. Several germline mutations of Wwox have been associated with infant neurological disorders characterized by epilepsy, growth retardation, and early death. Less is known, however, about the pathological link between Wwox mutations and these disorders or the physiological role of Wwox in brain development. In this study, we examined age-related expression and histological localization of Wwox in forebrains as well as the effects of loss of function mutations in the Wwox gene in the immature cortex of a rat model of lethal dwarfism with epilepsy (lde/lde). Immunostaining revealed that Wwox is expressed in neurons, astrocytes, and oligodendrocytes. lde/lde cortices were characterized by a reduction in neurite growth without a reduced number of neurons, severe reduction in myelination with a reduced number of mature oligodendrocytes, and a reduction in cell populations of astrocytes and microglia. These results indicate that Wwox is essential for normal development of neurons and glial cells in the cerebral cortex.

Nanomicelle curcumin-induced DNA fragmentation in testicular tissue; Correlation between mitochondria dependent apoptosis and failed PCNA-related hemostasis

Current study was done to assess possible anti-proliferative effect of nanomicelle curcumin (NMCM) against germ cells in testicular tissue. For this purpose, 24 mature male Wistar rats were divided into control and test groups. The animals in test groups received 7.5mg/kg, 15mg/kg and 30mg/kg of NMC (NO=6 rats in each group). Following 48days, the expression of Bcl-2, Bax, caspase-3, P53 and proliferating cell nuclear antigen (PCNA) were evaluated by using reverse transcription-PCR and immunohistochemistry. Histological changes, tubular differentiation index (TDI), tissue cellularity and serum level of testosterone were analyzed. Finally, the DNA laddering test was used to assess the DNA fragmentation as hallmark for apoptosis. The NMCM significantly (P<0.05) diminished the Bcl-2, p53 and PCNA and enhanced the Bax and caspase-3 mRNA levels. The NMCM significantly (P<0.05) elevated the percentage of Bax and caspase-3-positive tubules and remarkably reduced the percentage of tubules with positive reaction for Bcl-2, p53 and PCNA. The NCMN-received animals exhibited remarkable (P<0.05) reduction in cell population, TDI ratio and serum level of testosterone. Severe DNA fragmentation was observed in 30mg/kg NMCM-received group. In conclusion, the NMCM by reducing the testicular endocrine status, down-regulating Bcl-2 expression and by enhancing the Bax and caspase-3 expression initiates the intrinsic apoptosis pathway. On the other hand, inhibited expression of p53 and PCNA (at dose level of 30mg/kg) suppresses the p53 and PCNA-related hemostasis/preservative reactions. All these alterations adversely affect the spermatogenesis.

Apoptotic activity of isoespintanol derivatives in human polymorphonuclear cells

Background: Inflammation is a complex physiopathologic response to different stimuli. Recently, some pharmacological strategies have been proposed that could be used for resolution of inflammation by enhancing apoptosis of inflammatory cells. Objectives: To study in vitro apoptotic activity of isoespintanol [ISO] and of two semi-synthetic derivatives, bromide isoespintanol [BrI] and demethylated isoespintanol [DMI], in human polymorphonuclear (PMN) cells. Methods: PMN were exposed to the different concentrations of ISO, BrI and DMI for 30 min in phosphate-buffered saline pH 7.4 containing 1 mg/mL glucose, 0.4 mM Mg2+, and 1.20 mM Ca2+. Viability was assessed by dimethylthiazol diphenyl tetrazolium bromide (MTT). To distinguish between the two modes of cell death, apoptosis and necrosis, we examined differences in morphological and biochemical changes of cells stained with annexin V- FITC (An) and/or propidium iodide (PI) using two different assays based on flow cytometry Results: The MTT assay revealed the ability of cells to reduce MTT salt to formazan. In the presence of BrI and DMI a significant concentration-dependent decrease of cell viability was observed. The annexin V- FITC binding assay showed a high proportion of apoptotic cells for those treated with BrI (An+/ PI-: 62.3 ± 8.2% vs. 2.1 ± 0.5% of control, P<0.05). The population of PMN treated with DMI produced the highest percentage (An+/IP+: 43.4 ± 5.2 % vs. 0.4 ± 0.3 % of control, P<0.05) of necrotic cells. Apoptotic nuclei were analyzed by PI staining. The cell population in the sub G0/G1 region represents cells with hypodiploidal DNA, an indicator of apoptosis. When cells were incubated with 50 and 100 μM of BrI, the cell population in the sub G0/G1 region increased, suggesting a dose-dependent increase in the population of apoptotic cells. The presence of the pan-inhibitor of caspases (Z-VAD-fmk) showed a significant reduction in cell population in the sub G0/G1 region, indicating less degradation of DNA. Conclusions: Bromide isoespintanol [BrI] induces an apoptotic process in PMN, mediated –at least in part– by activation of caspases, although this compound may probably act through other caspase-independent mechanisms as well.

Dendrimerized Magnetic Nanoparticles as Carriers for the Anticancer Compound, Epigallocatechin Gallate

Green tea polyphenols have attracted significant interest due to their promising therapeutic potential as antitumor agents. These include catechins that have been explored for various tumors with minimal side effects. This paper demonstrates the fabrication and characterization of dendrimerized magnetic nanoparticles, as delivery vectors for epigallocatechin gallate (EGCG). Glutamic acid-functionalized iron oxide nanoparticles (Glu–Fe3O4) were synthesized and modified with the polyethylene glycol polyamidoamine dendrimers of generations 3, 5, and 6. Nanoparticles were characterized by X-ray diffraction, electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. In aqueous colloidal suspensions, they showed a rapid temperature increase under varying magnetic fields, suggesting their potential in chemothermal therapeutic applications. The loading efficiency of the dendrimerized nanoparticles was calculated to be 32.7%, 51.1%, and 56.4% for generations 3, 5, and 6, respectively. In acidic environments, a sustained drug release profile with an increasing but incomplete release was observed. Importantly, EGCG-loaded nanoparticles induced controlled cell death in human cervical cancer cells, demonstrating a 40% reduction in cell population over 24 h at the highest concentration used, with a linear dose-response.

A Genomic Study of DNA Alteration Events Caused by Ionizing Radiation in Human Embryonic Stem Cells via Next-Generation Sequencing.

Ionizing radiation (IR) is a known mutagen that is widely employed for medical diagnostic and therapeutic purposes. To study the extent of genetic variations in DNA caused by IR, we used IR-sensitive human embryonic stem cells (hESCs). Four hESC cell lines, H1, H7, H9, and H14, were subjected to IR at 0.2 or 1 Gy dose and then maintained in culture for four days before being harvested for DNA isolation. Irradiation with 1 Gy dose resulted in significant cell death, ranging from 60% to 90% reduction in cell population. Since IR is often implicated as a risk for inducing cancer, a primer pool targeting genomic “hotspot” regions that are frequently mutated in human cancer genes was used to generate libraries from irradiated and control samples. Using a semiconductor-based next-generation sequencing approach, we were able to consistently sequence these samples with deep coverage for reliable data analysis. A possible rare nucleotide variant was identified in the KIT gene (chr4:55593481) exclusively in H1 hESCs irradiated with 1 Gy dose. More extensive further studies are warranted to assess the extent and distribution of genetic changes in hESCs after IR exposure.

3-Bromopyruvate inhibits cell proliferation and induces apoptosis in CD133+ population in human glioma.

The study was aimed to investigate the role of 3-bromopyruvate in inhibition of CD133+ U87 human glioma cell population growth. The results demonstrated that 3-bromopyruvate inhibited the viability of both CD133+ and parental cells derived from U87 human glioma cell line. However, the 3-bromopyruvate-induced inhibition in viability was more prominent in CD133+ cells at 10μM concentration after 48h. Treatment of CD133+ cells with 3-bromopyruvate caused reduction in cell population and cell size, membrane bubbling, and degradation of cell membranes. Hoechst 33258 staining showed condensation of chromatin material and fragmentation of DNA in treated CD133+ cells after 48h. 3-Bromopyruvate inhibited the migration rate of CD133+ cells significantly compared to the parental cells. Flow cytometry revealed that exposure of CD133+ cells to 3-bromopyruvate increased the cell population in S phase from 24.5 to 37.9% with increase in time from 12 to 48h. In addition, 3-bromopyruvate significantly enhanced the expression of Bax and cleaved caspase 3 in CD133+ cells compared to the parental cells. Therefore, 3-bromopyruvate is a potent chemotherapeutic agent for the treatment of glioma by targeting stem cells selectively.

Vitexicarpin inhibits overexpression of GNAO1 and plays a role in gastric cancer cell proliferation and apoptosis

The present study demonstrates the effect of vitexicarpin on down-regulation of GNAO1 in human gastric cancer cell lines. The results from Western blot analysis revealed that vitexicarpin treatment inhibited the GNAO1 expression in MKN-45 cells at a concentration of 30 µM. Examination of cell proliferation using CCK-8 cell proliferation kit showed 70% reduction in the vitexicarpin treated cells compared to untreated control cells. Cell cycle analysis using propidium Iodide staining followed by flow cytometry showed cell cycle arrest at G0/G1 with reduction of cell population in the S-phase. There was a significant aneuploidy in the controls compared to zero aneuploidy in the GNAO1 down-regulated cells. Transwell chamber and scratch wound healing assay respectively showed 65% and 42% reduction in migration of vitexicarpin treatedMKN-45 cells. Therefore, vitexicarpin treated inhibition of GNAO1can be a potential therapeutic strategy for the treatment of gastric cancer.

Effect of radiotherapy on the eruption rate and morphology of the odontogenic region of rat incisors

ObjectiveThe goal in this study was to evaluate the results of doses of 5 and 15Gy of radiation in odontogenic region of the rats inferior mandibular-incisors by a histological analysis and the rate of eruptions. DesignAnimals were divided into three groups: control, radiotherapy 5Gy and radiotherapy 15Gy. In which tooth-eruption-rate was measured every two days. ResultsAnimals in Group 5Gy presented values similar to those of the control group. Animals in Group 15Gy presented reduction in tooth-eruption-rate as of the sixth day of the experiment, vast disorganization of odontoblasts and ameloblasts, apparent reduction in cell population in the follicle region and alterations in cervical loop formation of the dental organ. ConclusionsIt was concluded that there was a difference between the researched doses, and histological alteration at 15Gy lead to statistical reduction in tooth-eruption-rate.

THE EFFECT OF Mn(II) ON THE AUTOINDUCING GROWTH INHIBITION FACTOR IN Deinococcus radiodurans

Decreases in cell division at the stationary phase in bacterial cultures are often due to the depletion of nutrients and/or accumulation of toxic waste products. Yet, during the stationary phase, the highly radiation-resistant bacterium Deinococcus radiodurans undergoes new rounds of cell division when Mn(II) is added to the medium in a phenomenon known as manganese-induced cell division (MnCD). When cells were cultured in medium without Mn(II)-enrichment, a heat-resistant, proteinase K-resistant factor (or factors) with a molecular mass less than 10 kD accumulated in the spent medium. Inclusion of the concentrated spent medium in fresh medium could inhibit the growth of D. radiodurans significantly, and the degree of inhibition was dose dependent. However, the relative stimulatory effect of MnCD was also dose dependent—the higher the inhibition, the stronger was the MnCD response. Previous studies have shown that nutrients were not limiting and deinococcal cells would continue metabolizing its nutrients at stationary phase. Cells became more sensitive to radiation when nutrients in the medium eventually became depleted. We speculated that D. radiodurans might produce this factor in the medium to control its population density. The reduction in cell population would conserve the nutrients that in turn might enhance the survival of the species.

Microcysts in the inner nuclear layer from optic atrophy are caused by retrograde trans-synaptic degeneration combined with vitreous traction on the retinal surface

ARTICLE Sir, it has been reported that microcysts from macular oedema occur in 4.7% of patients with multiple sclerosis (Gelfand et al. , 2012). It is now evident that these microcysts do not represent oedema, nor is their occurrence a specific feature of demyelinating disease, because they have been identified in patients with Leber’s hereditary optic neuropathy, Kjer’s dominant optic atrophy, and optic glioma (Abegg et al. , 2012; Barboni et al. , 2013). However, their precise aetiology has remained a mystery. As pointed out by Abegg et al. (2012), the classical ocular pathology literature provides a clue to the formation of microcysts. Van Buren (1963) described retrograde trans-synaptic degeneration of the inner nuclear layer in histological sections of the retina after lesions of the optic nerve or chiasm, causing ‘cystic degeneration’ that resembles the ‘microcysts’ now being imaged with optical coherence tomography. Gills and Wadsworth (1967) found a 15–60% reduction in cell population in the inner nuclear layer in nine patients with longstanding blindness from compressive or traumatic lesions of the optic nerve. In at least three cases, microcycsts were present in the inner nuclear layer (Fig. 1). In two patients with more recent blindness, cell loss was not observed. Presumably, sufficient time had not elapsed for trans-synaptic degeneration to occur. Figure 1 ( A ) Histological section of the retina showing cysts in the inner nuclear layer following retrograde trans-synaptic degeneration from a tumour of the optic nerve. Reproduced from Gills and Wadsworth (1967) with permission from James P. Gills. ( B ) Image obtained by optical coherence tomography from a patient with optic atrophy, showing cysts in the inner nuclear layer. IPL = inner plexiform layer; INL = inner nuclear layer; OPL = outer plexiform layer; HFL = Henle fibre layer; ONL = outer nuclear layer. Gills and Wadsworth (1967) also …

SU-E-T-271: Irradiating a Single Hippocampus in a Small Rodent Using VMAT- RapidArc SRS: Preliminary Data.

To develop and optimize the procedures for the precise irradiation of the hippocampal region in a rodent with minimum radiation dose to the remainder of the brain. For this purpose, VMAT-RapidArc SRS was used to irradiate one hippocampus of athymic nude (ATN) rats. Prescribed dose was verified through TLD measurements and spared brain region(s) were confirmed through immunohistochemical analysis postmortem. Seven ATN rats, 10-12 weeks old underwent human-like radiation treatment planning followed by SRS. MRI and CT axial images of 0.8 mm thickness of the rat's skull were acquired and transferred to ECLIPSE treatment planning software where brain, right and left hippocampi were contoured. A VMAT-RapidArc plan consisting of two 3600 axial arcs and two 1200 vertex arcs irradiated the left hippocampus only to a dose of 10 Gy. Treatment was delivered using a 6 MV photon beam from a Trilogy Linac equipped with OBI. TLD measurements were performed prior to treatment using a custom made phantom that simulated the rat's brain and body. Orthogonal x-ray images taken with the OBI and co-registered to DRR images were used to adjust the rat's treatment position. One month post- irradiation, rats were sacrificed and brain dissection was performed to verify the radiation effects in the targeted and non-targeted regions. Percent differences between calculated and measured dose were ∼12% which was expected due to the small field sizes (<2cm) used. Immunohistochemistry analysis revealed a significant reduction in cell population in the ipsilateral hippocampus while cell populations comparable to those in a non-irradiated subject were observed in the contralateral hippocampal region. Present results demonstrate that precise irradiation of small volumes within a rat's brain can be achieved with human-like image-guided VMAT-RapidArc treatment. Postmortem analysis of the rat brain provides evidence of high-precision targeted radiation damage and dose sparing.

Targeted Hippocampal Irradiation in a Small Rodent Using IMRS and RapidArc SRS: Preliminary Data

To use a rodent model to develop and optimize the procedures for the precise irradiation of the hippocampal region with minimum radiation dose to the remainder of the brain. For this purpose, IMRS and RapidArc VMAT SRS were used to irradiate one and two hippocampi, respectively, of athymic nude (ATN) rats. Prescribed dose was verified using Mapcheck while irradiated and spared brain region(s) were confirmed through brain cell staining postmortem. Seven ATN rats, 6 - 8 weeks old underwent human-like radiation treatment planning followed by image-guided SRS. MRI and CT axial images 0.8-mm thickness of the rat's skull were acquired and transferred to ECLIPSE treatment planning software to aid in contouring the brain, right and left hippocampi. A 6-field non-coplanar IMRS plan was generated to target the left hippocampus to a dose of 10 Gy while a coplanar two-arc RapidArc SRS plan targeted both hippocampi also to 10 Gy. Treatment was delivered using a 6 MV photon beam from a Varian Trilogy Linac equipped with on-board imaging (OBI). Prior to treatment, the dose was verified through a QA plan generated from the treatment plan and delivered to a Mapcheck detector array imbedded in a virtual water phantom. Orthogonal x-ray images taken with the OBI and co-registered to DRR images from the planning CT were used to precisely adjust the rat's treatment position. One month post-irradiation, rats were euthanized and 30-micron thick brain sections were evaluated using an immunocytochemical technique to verify the radiation effects in the targeted and non-targeted regions. Table 1 presents dosimetric results for one and two hippocampi irradiation using IMRS and RapidArc SRS, respectively. Percent differences between calculated and measured dose using Mapcheck for one hippocampus and two hippocampi were 5.0% and 2.0%, respectively. Cell staining performed in the single hippocampus irradiation cases revealed a significant reduction in cell population in the ipsilateral hippocampus while populations comparable to those in a non-irradiated subject were observed in the contralateral hippocampal region. Present results demonstrate that precise irradiation of small volumes within a rat's brain can be achieved with human-like image-guided IMRS and RapidArc SRS treatments. Postmortem clinical analysis of the rat brain provides evidence of high-precision targeted radiation damage and dose sparing.Table 1One Hippocampus (n = 2)Two Hippocampi (n = 5)Min (Gy)Max (Gy)Mean (Gy)Min (Gy)Max (Gy)Mean (Gy)Left Hippocampus7.013.611.79.410.710.2Right Hippocampus0.12.80.79.710.910.4Brain w/ Hippocampi0.113.62.60.611.04.4Brain w/o Hippocampi0.18.51.90.68.03.2 Open table in a new tab

Heavy metals uptake by Euglena proxima isolated from tannery effluents and its potential use in wastewater treatment

The flagellate, Euglena proxima, isolated from industrial wastewater showed tolerance against Cr6+ (20 μg/ml) and Pb2+ (30 μg/ml). The metal ions slowed down the growth of the organism after 4–5 days of exposure. The reduction in cell population was 68% for Cr6+ and 59% for Pb2+ after 8 days of metal stress. The order of resistance to heavy metals, in terms of reduction in the cellular population, was Pb2+ > Cr6+. Chromium and lead processing capabilities of Euglena proxima were worked out for its potential use as biore-mediator of wastewater. The reduction in the amount of Cr6+ after 7, 14 and 21 days of flagellate culturing containing 5 μg Cr6+/ml of culture medium was 76, 80 and 88%, respectively. Euglena proxima could also remove 78% Pb2+ after 7 days, 82% after 14 days and 90% after 21 days from the culture medium. The acid digestion of Euglena proxima showed 84% of Cr6+ and 88% of Pb2+ ions accumulated in the organism. The heavy metal uptake ability of Euglena proxima can be exploited for metal detoxification and environmental clean-up operations.

Enhancing the Lethal Effect of High-Intensity Pulsed Electric Field in Milk by Antimicrobial Compounds as Combined Hurdles

High-intensity pulsed electric field (HIPEF) is a nonthermal treatment studied for its wide antimicrobial spectrum on liquid food, including milk and dairy products. Moreover, the antimicrobial effect of HIPEF may be enhanced by combining HIPEF with other treatments as hurdles. Nisin and lysozyme are natural antimicrobial compounds that could be used in combination with HIPEF. Therefore, the purpose of this study was to determine the effect of combining HIPEF with the addition of nisin and lysozyme to milk inoculated with Staphylococcus aureus with regard to different process variables. The individual addition of nisin and lysozyme did not produce any reduction in cell population within the proposed range of concentrations, whereas their combination resulted in a pH-dependent microbial death of Staph. aureus. The addition of nisin and lysozyme to milk combined with HIPEF treatment resulted in a synergistic effect. Applying a 1,200-μs HIPEF treatment time to milk at pH 6.8 containing 1IU/mL of nisin and 300IU/mL of lysozyme resulted in a reduction of more than 6.2 log units of Staph. aureus. Final counts resulting from the addition of nisin and lysozyme and applying HIPEF strongly depended on both the sequence of application and the milk pH. Thus, more research is needed to elucidate the mode of action of synergism as well as the role of different process variables, although the use of HIPEF in combination with antimicrobial compounds such as nisin and lysozyme is shown to be potentially useful in processing milk and dairy products.

Uptake of heavy metals by Stylonychia mytilus and its possible use in decontamination of industrial wastewater

The heavy metal resistant ciliate, Stylonychia mytilus, isolated from industrial wastewater has been shown to be potential bioremediator of contaminated wastewater. The ciliate showed tolerance against Zn2+ (30 μg/mL), Hg2+ (16 μg/mL) and Ni2+ (16 μg/mL). The metal ions slowed down the growth of the ciliate as compared with the culture grown without metal stress. The reduction in cell population was 46% for Cd2+, 38% for Hg2+, 23% for Zn2+, 39% for Cu2+ and 51% for Ni2+ after 8 days of metal stress. S. mytilus reduced 91% of Cd2+, 90% of Hg2+ and 98% of Zn2+ from the medium after 96 h of incubation in a culture medium containing 10 μg/mL of the respective metal ions. Besides this, the ciliate could also remove 88% of Cu2+ and 73% Ni2+ from the medium containing 5 μg/mL of each metal after 96 h. The ability of Stylonychia to take up variety of heavy metals from the medium could be exploited for metal detoxification and environmental clean-up operations.

Heavy metal resistant Distigma proteus (Euglenophyta) isolated from industrial effluents and its possible role in bioremediation of contaminated wastewaters

The alga, Distigma proteus, isolated from industrial wastewater showed tolerance against Cd2+ (8.0 μg/ml), Cr6+ (12 μg/ml), Pb2+ (15 μg/ml) and Cu2+ (10 μg/ml). The metal ions slowed down the growth of the organism after 4–5 days of exposure. The reduction in cell population was 90% for Cu2+, 84% for Cd2+, 71% for Cr6+, and 63% for Pb2+ after 8 days of metal stress. The order of resistance to heavy metal, in terms of reduction in the cellular population, was Cu2+ > Cd2+ > Cr6+ > Pb2+. Chromium- and cadmium-processing capabilities of the alga were worked out for its potential use as a bioremediator of wastewater. The reduction in the amount of Cr6+ after 2, 4, 6 and 8 days of algal culture containing 5.0 μg Cr6+ ml−1 of culture medium was 77, 85, 92 and 97%, respectively. Distigma could also remove 48% Cd2+after 2 days, 68% after 4 days, 80% after 6 days and 90% after 8 days from the medium. The heavy metal uptake ability of Distigma can be exploited for metal detoxification and environmental clean-up operations.