Potentialities of fluorescent carbon nanomaterials as sensor for food analysis

Food safety and quality are among the most significant and prevalent research areas worldwide. The fabrication of appropriate technical procedures or devices for the recognition of hazardous features in foods is essential to safeguard food materials. In the recent era, developing high-performance sensors based on carbon nanomaterial for food safety investigation has made noteworthy progress. Hence this review briefly highlights the different detection approaches (colorimetric sensor, fluorescence sensor, surface-enhanced Raman scattering, surface plasmon resonance, chemiluminescence, and electroluminescence), functional carbon nanomaterials with various dimensions (quantum dots, graphene quantum dots) and detection mechanisms. Further, this review emphasizes the assimilation of carbon nanomaterials with optical sensors to identify multiple contaminants in food products. The insights of carbon-based nanomaterials optical sensors for pesticides and insecticides, toxic metals, antibiotics, microorganisms, and mycotoxins detection are described in detail. Finally, the opportunities and future perspectives of nanomaterials-based optical analytical approaches for detecting various food contaminants are discussed.     

Food restricting young hamsters (Mesocricetus auratus) affects sex ratio and growth of subsequent offspring

Trivers and Willard (1973) predicted that stressed adult female mammals may enhance their fitness by skewing offspring sex ratios and maternal investment to favor daughters. The present study investigated whether stressing young hamsters might also influence sex ratio and growth of subsequent offspring. Control females received food ad libitum (A) on Days 1-50 postpartum (AA). Experimental females were food-restricted (R) either on Days 1-25 (RA), Days 26-50 (AR), or Days 1-50 (RR) postpartum. Subjects were mated when 91-95 days old. Litter sizes and survivorship (= % litters within a treatment that contained at least one pup), sex ratio (= % males), and pup weights in the next generation were recorded every fifth day from parturition until Day 25 postpartum. Control litters contained significantly more offspring at birth than did RR litters. Sex ratio was significantly higher at birth for AA litters than for the other treatments. Postpartum sex ratio within each group remained similar to that recorded at birth. RR litters contained significantly fewer pups compared to the other three treatments from Days 5-25. RR female pups weighed significantly more at birth than their counterparts in the other treatments. Weights of males at birth were similar in all treatments. By Day 25, both male and female RR pups weighed significantly less than control, AR, and RA pups. Food restriction early in life may have long-term consequences on sex ratio and pup growth in golden hamsters.     

Habitat suitability,corridors and dispersal barriers for large carnivores in Poland

Carnivores are often particularly sensitive to landscape fragmentation. Ecological corridors may help to connect local populations, ensuring gene flow and retaining viable meta-populations. We aimed to establish habitat suitability models for two large carnivores in Poland, the grey wolf Canis lupus Linnaeus, 1758 and the Eurasian lynx Lynx lynx Linnaeus, 1758, based on ecological niche factor analysis (ENFA). Secondly, we calculated least cost paths (LCPs) based on cost values obtained from ENFA. Thirdly, we determined structures that might act as barriers, thus diminishing the value of the corridor unless appropriate conservation measures are taken. We compared some of the results with actual dispersal data of four lynx in eastern Poland. Results indicate that both species are highly marginalised. Less habitat that is currently available in Poland is suitable for lynx than for wolves. We determined a total of 76 LCPs. Comparison of these theoretical corridors with actual dispersal routes suggests that the traits of calculated LCPs are mostly within the range of those of real routes. We highlight a variety of features that might act as barriers, such as major roads (including planned highways), urbanized areas, and large un-forested areas. We give suggestions where concerted conservation efforts (eg wildlife passages) might be particularly well-directed.     

Effect of polymer brush architecture on antibiofouling properties

Polymer brushes show great promise in next-generation antibiofouling surfaces. Here, we have studied the influence of polymer brush architecture on protein resistance. By carefully optimizing reaction conditions, we were able to polymerize oligoglycerol-based brushes with sterically demanding linear or dendronized side chains on gold surfaces. Protein adsorption from serum and plasma was analyzed by surface plasmon resonance. Our findings reveal a pronounced dependence of biofouling on brush architecture. Bulky yet flexible side chains as in dendronized brushes provide an ideal environment to repel protein-possibly through formation of a hydration layer, which can be further enhanced by presenting free hydroxyl groups on the polymer brushes. A deeper understanding of how brush architecture influences protein resistance will ultimately enable fabrication of surface coatings tailored to specific requirements in biomedical applications.     

Subunit composition of α5-containing nicotinic receptors in the rodent habenula

Gene association studies in humans have linked the α5 subunit gene CHRNA5 to an increased risk for nicotine dependence. In the CNS, nicotinic acetylcholine receptors (nAChRs) that contain the α5 subunit are expressed at relatively high levels in the habenulo-interpeduncular system. Recent experimental evidence furthermore suggests that α5-containing receptors in the habenula play a key role in controlling the intake of nicotine in rodents. We have now analysed the subunit composition of hetero-oligomeric nAChRs in the habenula of postnatal day 18 (P18) C57Bl/6J control mice and of mice with deletions of the α5, the β2, or the β4 subunit genes. Receptors consisting of α3β4* clearly outnumbered α4β2*-containing receptors not only in P18 but also in adult mice. We found low levels of α5-containing receptors in both mice (6%) and rats (2.5% of overall nAChRs). Observations in β2 and β4 null mice indicate that although α5 requires the presence of the β4 subunit for assembling (but not of β2), α5 in wild-type mice assembles into receptors that also contain the subunits α3, β2, and β4.     

Genbank accession #: AF139098

Plant Molecular Biology -     

RNA-dependent synthesis of ergosteryl-3β-O-glycine in Ascomycota expands the diversity of steryl-amino acids

A wide range of bacteria possess virulence factors such as aminoacyl-tRNA transferases (ATTs) that are capable of rerouting aminoacyl-transfer RNAs away from protein synthesis to conjugate amino acids onto glycerolipids. We recently showed that, although these pathways were thought to be restricted to bacteria, higher fungi also possess ergosteryl-3β-O-L-aspartate synthases (ErdSs), which transfer the L-Asp moiety of aspartyl-tRNA^Asp onto the 3β-OH group of ergosterol (Erg), yielding ergosteryl-3β-O-L-aspartate (Erg-Asp). Here, we report the discovery, in fungi, of a second type of fungal sterol-specific ATTs, namely, ergosteryl-3β-O-glycine (Erg-Gly) synthase (ErgS). ErgS consists of a freestanding DUF2156 domain encoded by a gene distinct from and paralogous to that of ErdS. We show that the enzyme only uses Gly-tRNA^Gly produced by an independent glycyl-tRNA synthetase (GlyRS) to transfer glycine onto the 3β-OH of Erg, producing Erg-Gly. Phylogenomics analysis also show that the Erg-Gly synthesis pathway exists only in Ascomycota, including species of biotechnological interest, and more importantly, in human pathogens, such as Aspergillus fumigatus. The discovery of a second type of Erg-aa not only expands the repertoire of this particular class of fungal lipids but suggests that Erg-aa synthases might constitute a genuine subfamily of lipid-modifying ATTs.     

Activation and route of administration both determine the ability of bone marrow-derived dendritic cells to accumulate in secondary lymphoid organs and prime CD8<Superscript>+</Superscript> T cells against tumors

Aims

To examine the effects of route of administration and activation status on the ability of dendritic cells (DC) to accumulate in secondary lymphoid organs, and induce expansion of CD8⁺ T cells and anti-tumor activity.

Methods

DC from bone marrow (BM) cultures were labeled with fluorochromes and injected s.c. or i.v. into naïve mice to monitor their survival and accumulation in vivo. Percentages of specific CD8⁺ T cells in blood and delayed tumor growth were used as readouts of the immune response induced by DC immunization.

Results

The route of DC administration was critical in determining the site of DC accumulation and time of DC persistence in vivo. DC injected s.c. accumulated in the draining lymph node, and DC injected i.v. in the spleen. DC appeared in the lymph node by 24 h after s.c. injection, their numbers peaked at 48 h and declined at 96 h. DC that had spontaneously matured in vitro were better able to migrate compared to immature DC. DC were found in the spleen at 3 h and 24 h after i.v. injection, but their numbers were low and declined by 48 h. Depending on the tumor cell line used, DC injected s.c. were as effective or more effective than DC injected i.v. at inducing anti-tumor responses. Pre-treatment with LPS increased DC accumulation in lymph nodes, but had no detectable effect on accumulation in the spleen. Pre-treatment with LPS also improved the ability of DC to induce CD8⁺ T cell expansion and anti-tumor responses, regardless of the route of DC administration.

Conclusions

Injection route and activation by LPS independently determine the ability of DC to activate tumor-specific CD8⁺ T cells in vivo.