Scalability of biomass-derived graphene derivative materials as viable anode electrode for a commercialized microbial fuel cell: A systematic review

Microbial fuel cell(MFC) is an advanced bioelectrochemical technique that can utilize biomass materials in the process of simultaneously generating electricity and biodegrading or bio transforming toxic pollutants from wastewater. The overall performance of the system is largely dependent on the efficiency of the anode electrode to enhance electron transportation. Furthermore, the anode electrode has a significant impact on the overall cost of MFC setup. Hence, the need to explore research focused towards developing cost-effective material as anode in MFC. This material must also have favourable properties for electron transportation. Graphene oxide(GO) derivatives and its modification with nanomaterials have been identified as a viable anode material. Herein, we discussed an economically effective strategy for the synthesis of graphene derivatives from waste biomass materials and its subsequent fabrication into anode electrode for MFC applications. This review article offers a promising approach towards replacing commercial graphene materials with biomass-derived graphene derivatives in a view to achieve a sustainable and commercialized MFC.

Extracellular vesicles from oviductal and uterine fluids supplementation in sequential in vitro culture improves bovine embryo quality

Background:In vitro production of bovine embryos is a well-established technology,but the in vitro culture(IVC)system still warrants improvements,especially regarding embryo quality.This study aimed to evaluate the effect of extracellular vesicles(EVs)isolated from oviductal(OF)and uterine fluid(UF)in sequential IVC on the development and quality of bovine embryos.Zygotes were cultured in SOF supplemented with either BSA or EVs-depleted fetal calf serum(dFCS)in the presence(BSA-EV and dFCS-EV)or absence of EVs from OF(D1 to D4)and UF(D5 to D8),mimicking in vivo conditions.EVs from oviducts(early luteal phase)and uterine horns(mid-luteal phase)from slaughtered heifers were isolated by size exclusion chromatography.Blastocyst rate was recorded on days 7-8 and their quality was assessed based on lipid contents,mitochondrial activity and total cell numbers,as well as survival rate after vitrification.Relative mRNA abundance for lipid metabolism-related transcripts and levels of phosphorylated hormonesensitive lipase(pHSL)proteins were also determined.Additionally,the expression levels of 383 miRNA in OF-and UF-EVs were assessed by qRT-PCR.Results:Blastocyst yield was lower(P<0.05)in BSA treatments compared with dFCS treatments.Survival rates after vitrification/warming were improved in dFCS-EVs(P<0.05).EVs increased(P<0.05)blastocysts total cell number in dFCS-EV and BSA-EV compared with respective controls(dFCS and BSA),while lipid content was decreased in dFCSEV(P<0.05)and mitochondrial activity did not change(P>0.05).Lipid metabolism transcripts were affected by EVs and showed interaction with type of protein source in medium(PPARGC1B,LDLR,CD36,FASN and PNPLA2,P<0.05).Levels of pHSL were lower in dFCS(P<0.05).Twenty miRNA were differentially expressed between OF-and UF-EVs and only bta-miR-148b was increased in OF-EVs(P<0.05).Conclusions:Mimicking physiological conditions using EVs from OF and UF in sequential IVC does not affect embryo development but improves blastocyst quality regarding survival rate after vitrification/warming,total cell number,lipid content,and relative changes in expression of lipid metabolism transcripts and lipase activation.Finally,EVs miRNA contents may contribute to the observed effects.

Impact of hormonal modulation at proestrus on ovarian responses and uterine gene expression of suckled anestrous beef cows

Background： This study evaluated the impact of hormonal modulation at the onset of proestrus on ovarian response and uterine gene expression of beef cows.Methods： A total of 172 anestrous beef cows were assigned to one of four groups according to the treatment with estradiol cypionate（ECP） and/or equine chorionic gonadotropin（eCG） [CON（n = 43）, ECP（n = 43）, eCG（n = 44）and ECP ＋ eCG（n = 42）].Results： ECP-treated cows（ECP and ECP ＋ eCG groups） presented greater occurrence of estrus（44.6% vs. 65.4%; P = 0.01） and pregnancy per AI [47.1% vs. 33.3%; P = 0.07], but similar progesterone（P4） concentration at subsequent diestrus than cows not treated with ECP（CON and eCG groups）. Nonetheless, eCG-treated cows（eCG and ECP ＋ eCG groups） presented larger follicle at timed AI（12.6 ± 0.3 vs. 13.5 ± 0.3 mm; P = 0.03）, greater ovulation rate（96.5%vs. 82.6%; P = 0.008） and greater P4 concentration at d 6（3.9 ± 0.2 vs. 4.8 ± 0.2 ng/mL; P = 0.001） than cows not treated with eCG（CON and ECP groups）. Next, cows with a new corpus luteum 6 d after TAI were submitted to uterine biopsy procedure. Uterine fragments [CON（n = 6）, ECP（n = 6）] were analyzed by RNA-Seq and a total of 135 transcripts were differentially expressed between groups（73 genes up-regulated by ECP treatment）. Subsequently,uterine samples were analyzed by q PCR（genes associated with cell proliferation）. ECP treatment induced greater abundance of PTCH2（P = 0.07） and COL4 A1（P = 0.02）, whereas suppressed EGFR（P = 0.09） expression. Conversely, eCG treatment increased abundance of HB-EGF（P = 0.06）, ESR2（P = 0.09）, and ITGB3（P = 0.05）, whereas it reduced transcription of ESR1（P = 0.05）. Collectively, supplementation with ECP or eCG at the onset of proestrous of anestrous beef cows influenced ovarian responses, global and specific endometrial gene expression.Conclusion： Proestrus estradiol regulate the endometrial transcriptome, particularly stimulating proliferative activity in the endometrium.

Optimization of Zeaxanthin Production by Immobilized <i>Flavobacterium</i>sp. Cells in Fluidized Bed Bioreactor

From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the modern technology, has increased the production of metabolites of interest. The microbiological production of carotenoids has not been optimized to obtain pigment production quantities of pigments and carotenoids recovery that lower production costs. The aim of this work was to design a Zeaxanthin production process with Flavobacterium sp. immobilized cells in a fluidized bed bioreactor. An optimum culture medium for Zeaxanthin production in stirred flasks (2.46 g·L–1) was obtained. Furthermore, optimum process conditions for a maximum yield of Zeaxanthin production, by fluidized bed bioreactor, were established. A statistical analysis showed that the most significant factors were air flow, pH and NaCl concentration (4.5 g·L–1). In this study a maximum Zeaxanthin production of 3.8 g·L–1 was reached. The highest reported yield to date was 0.329 g·L–1.

Selection of Bacillus thuringiensis strains in citrus and their pathogenicity to Diaphorina citri (Hemiptera: Liviidae) nymphs

Bacillus thuringiensis(Bt)toxins are effective in controlling insect pests either through the spraying of products or when expressed in transgenic crops.The discovery of endophytic Bt strains opened new perspectives for studies aimed at the control of sap‐sucking insects,such as the Asian citrus psyllid Diaphorina citri Kuwayama(Hemiptera:Liviidae),a vector of“Candidatus Liberibacter spp.,”associated with citrus huanglongbing(HLB).In this study,translocation of endophytic Bt strains in citrus seedlings inoculated with Bt suspension delivered by soil‐drench,and their systemic pathogenicity to D.citri nymphs were investigated.The pathogenicity of three wild‐type Bt strains against D.citri third‐instar nymphs was demonstrated.Among the 10 recombinant strains tested(each of them harboring a single cry or cyt gene),3 can be highlighted,causing 42%–77%and 66%–90%nymphal mortality at 2 and 5 d after inoculation,respectively.The isolation of Bt cells from young citrus shoots and dead nymphs,and PCR performed with specific primers,confirmed the involvement of the Bt strains in the psyllid mortality.This is the first report showing the translocation of Bt strains from citrus seedling roots to shoots and their potential to control D.citri nymphs that fed on these soil‐drench inoculated seedlings.The Bt strains that caused the highest mortality rates have the potential to be used as bioinsecticides to control D.citri and the identified genes can be used for the production of transgenic Bt citrus.