Naive animals, always starting from the same location in the maze (the “south” arm), were trained to selleck chemical find

a fixed target site (in the “east” arm) (Training I in Figure 6A). In order to facilitate developing habit-based navigation, the north and the west arms were both closed. It has been shown that under this paradigm, normal mice would learn to search the target using spatial reference memory after moderate training but would switch to habitual navigation after extensive training ( Packard and McGaugh, 1996). Probe trials, during which the start location switched from the “south” arm to the “north” arm, were given at different time points to allow dissociation of the spatial and habitual strategies. Thus, mice using the “habit strategy” were predicted to turn right (into the “west” arm), whereas the “spatial” mice, guided by distal spatial cues, were predicted to go to the “east” arm, where the target resided during training. All mice were trained in ten trials per day for 5 consecutive

days before the first probe trial on day 6 (Probe 1 in Figure 6A). During this probe trial the DA-NR1-KO group and control mice showed Selleckchem SCH 900776 similar preferences (χ2 [3, n = 43] = 0.346; p = 0.951) for the “spatial” strategy, opting to turn left toward the “east” arm (Figure 6B), suggesting that they had similarly acquired the spatial memory and that they shared comparable

motivation. All mice were then trained for 10 additional days before the second probe trial (Probe 2 in Figure 6A) on day 17. During this probe trial no significant differences were found among the three control groups (χ2 [2, n = 29] = 0.499; p = 0.779). As a group, control mice opted to “turn right” (and into the “west” arm) significantly more on day 17 than on day 6 (χ2 [1, n = 29] = 22.587; p = 0.00000201), indicating a learned “habit”-based searching strategy. In contrast, less than 10% of the DA-NR1-KO mice (compared with 80% of control mice) (mutants versus controls: χ2 = 7.244; p = 0.007) opted to turn “right” on day 17 (Figure 6B), suggesting that they failed to learn the “habit”-based strategies and, instead, kept using the “spatial” strategy. To confirm that the deficits in the plus maze tasks were indeed Cell press from habit learning, right after the second probe trial, mice were further challenged in a “relearn after 90° rotation” procedure (Training II, Figure 6A), three trials a day for 2 days within the exact same maze and surrounding cues. During the training, both the west and south arms were blocked. The start box was placed in the “east” arm, and the food rewards were in the “north” arm. Mice were tested in a rotation test on day 19, and accuracies to locate the food were scored. Mice started from the “east” arm with all arms open during the test (Figure 6A).

, 2002 and Schiller, 1993). In contrast, V4 lesions produce striking deficits in more complex perceptual tasks.

For example, V4 lesions lead to loss of ability to discriminate images of 3D objects (Merigan and Pham, 1998), loss of color constancy (Walsh et al., 1993), and deficits in the ability to select relatively less salient objects from an array, or to generalize 3-deazaneplanocin A across different stimulus configurations (Schiller, 1993, De Weerd et al., 1996 and De Weerd et al., 1999). A very large number of neurophysiological experiments on V4 have focused on attention. In fact it would not be an exaggeration to say that much of our understanding of the neural mechanisms mediating attention has been informed by neurophysiological studies in monkey V4. Note that, while under natural behavioral conditions primates foveate objects of attention, most neurophysiological studies have been conducted in extrafoveal regions of V4 in monkeys performing covert attention tasks (e.g., attending to nonfoveal stimuli while maintaining fixation on a central location). Development of fMRI over the past 15 years has dramatically advanced our understanding of human V4 and indicates that, to a large extent, human V4 is organizationally

and functionally analogous to macaque V4. The retinotopic organization of area V4 and nearby visual areas appears JAK inhibitor similar in humans (Sereno et al., 1995 and Hansen et al., 2007) and macaques (Fize et al., 2003 and Gattass et al., 1988). That is, humans appear to possess an inferior field representation of V4 dorsally and a superior field representation ventrally (Hansen et al., 2007). However, some others report a complete hemifield representation within ventral human V4 and conclude that no dorsal V4 exists in humans (Wade et al., 2002, Winawer et al., 2010 and Goddard et al., 2011). Beyond retinotopy, many fMRI studies of V4 are broadly consistent with what would be expected based on neurophysiological studies

in monkey V4. However, this comparison is difficult to make because interpretation of GPX6 fMRI results in terms of the underlying neural mechanisms is problematic (Buxton et al., 2004 and Logothetis and Wandell, 2004). In any case, from a comparative evolutionary viewpoint, it is likely that many commonalities exist between monkey V4 and human V4, but there may also be specializations in the human that are not present in the monkey. There have long been suggestions that V4 contains functional compartments. The original evidence for this idea comes from anatomical studies in which retrograde tracer injections in V4 labeled either predominantly thin stripes (associated with color) or pale stripes (associated with form) in area V2 and did not label thick stripes (associated with depth) (DeYoe et al., 1994). Furthermore, tracer injections in inferotemporal areas (PITv and PITd) result in interdigitated segregated label in V4 (DeYoe et al., 1994), indicating some degree of continued functional streaming in the ventral pathway.

, 2002 and Manglapus et al., 2004): Mash1+

GBCs are destroyed by the MeBr, but they reappear in increased numbers SCH 900776 cost two days after the MeBr. Ngn1/NeuroD+ cells are also lost with MeBr damage, but are present 3 days after the damage ( Guo et al., 2010) and precede production of new receptor neurons, which appear by 4 days postlesion. Hes1 is expressed by the sustentacular cells in the normal epithelium, but after MeBr, GBCs also express Hes1, and some of these go on to differentiate into sustentacular cells. Since the olfactory epithelium displays such robust regeneration it begs the question as to why we lose olfactory sensation as we age. The loss of sensory perception can result from changes in the sensory epithelia or, alternatively, from changes in the brain critical for processing the sensory information. There is evidence, however, that the number of receptor cells declines with age in humans. Moreover, in rats and mice, the density A-1210477 of proliferating (BrdU+) cells in the epithelium declines as the size of the epithelium grows (Weiler and Farbman, 1997); thus, while the overall number of proliferating cells does not decline by very much, the turnover of the receptor neurons, as indicated by the number of BrdU/OMP+ cells, declines with age (Kondo et al., 2010). This decline is also seen in the vomeronasal organ of mice, where Brann and Firestein (2010) reported that

the number of proliferating cells declines with age. Taken together, these studies suggest that the production of new receptor cells may not be able to keep pace with the increased loss of these cells that accompanies

increasing age. Some of the first evidence for regeneration of hair cells came from studies of the lateral line organs in fish and amphibia. The lateral line organs of fish and amphibia consist of mechanosensory neuromasts distributed along the body surface. In urodeles, after amputation of the tip of the tail, new neuromasts are generated in the lateral line organ at the stump and migrate to form new organs as the tail regenerates (Stone, 1937). Studies by Jones and because Corwin demonstrated that a low level of ongoing hair cell production is dramatically upregulated after hair cells in the lateral line are destroyed with a laser (Jones and Corwin, 1993 and Jones and Corwin, 1996). Direct time-lapse recordings demonstrated that the regenerated hair cells arose from support cells (Jones and Corwin, 1993). A similar increase in mitotic proliferation in the support cells occurs in zebrafish after various types of ototoxic damage (Hernández et al., 2007, Ma et al., 2008 and Williams and Holder, 2000), and the proliferating support cells go on to replace the hair cells within 48 hr of the insult. Hair cell regeneration has also been extensively studied in both auditory and vestibular sensory organs.

First, the rate of increase in inhibitory activity with increasing competitor strength was steeper in the presence of reciprocal inhibition ( Figure S3B, solid magenta versus dashed magenta lines). This increase in steepness reflected, as expected, an iterative amplification of the difference in activity between the two inhibitory units, due to the inhibitory feedback motif. Second, when another CRP was obtained with a different RF stimulus (14°/s), the steady-state inhibitory activity of inhibitory unit 2 FG-4592 datasheet was conspicuously shifted to the right ( Figure S3B, solid blue versus solid

magenta), in contrast to the results from the feedforward circuit ( Figure S2E). This rightward shift in the steady-state inhibitory activity predicted that, following a change in the strength of the RF stimulus, output unit

CRPs would also shift adaptively. We tested this prediction below. For subsequent simulations, we chose the reciprocal-inhibitory parameter values as follows: rin = 0.84 (which yielded the maximum rightward shift of the inhibitory activity; Figure S3C) and rout = 0.01 ( Figure S3D). We asked whether a circuit with reciprocal inhibition of feedforward lateral inhibition could produce the two response signatures critical for categorization in the OTid. To Crenolanib test whether this circuit model can produce switch-like CRPs at the output (OTid) units, we simulated output unit CRPs and, as before (Figure 3B), plotted their transition ranges as a function of each of the

parameters of the inhibitory-response function (Figure 5B). For these plots, the values of din and dout and the values of Histone demethylase the fixed inhibitory parameters were chosen to be the same as those used previously in testing circuit 1 ( Figure 3B). We found that large enough values of the saturation parameter k and small enough values of the half-maximum response loom speed (S50) yielded switch-like CRPs ( Figure 5B). An example of a switch-like CRP, obtained with the same values of the inhibitory parameters used for circuit 1 ( Figure 3C), is shown in Figure 5C. As expected by the steeper inhibitory-response function ( Figure S3B, solid versus dashed magenta), this CRP at the output unit is also steeper (compare with Figure 3C). Next, we tested whether this circuit can produce adaptive shifts in the CRP switch value. As before, we asked whether any combination of input and output divisive inhibition (din and dout, respectively; (2) and (3)) could produce a shift in the CRP switch value with a 6°/s increase in the RF stimulus strength. The strength of reciprocal inhibition was unchanged from before (rin = 0.84 and rout = 0.01). A plot of model CRP shift ratios (ratio of switch-value shift to change in RF stimulus strength) as a function of din and dout shows that a large set of (din, dout) values successfully produced adaptive shifts in the switch value (shift ratio near 1; Figure 5D and Figure S4A).

Interestingly, the dGcn5 HAT is not important for ddaC dendrite pruning,

despite its role in facilitating ecdysone signaling and the onset of metamorphosis ( Carré et al., 2005). No pruning defects were observed in dGcn5 RNAi knockdown ddaC neurons (data not shown) or in the MARCM ddaC clones of two dGcn5 null/strong alleles (n = 5; Figure S3D; Table S3). Thus, CBP, but not dGcn5, is required for ddaC dendrite pruning during early metamorphosis. To further verify the requirement of CBP Selleck Ibrutinib for pruning, we overexpressed the dominant-negative form of CBP, which lacks the C-terminal transactivation domain (CBP-ΔQ; Kumar et al., 2004), in ddaC neurons. A strong dendrite-pruning defect was observed with an average of 8.3 primary and secondary dendrites attached in CBP-ΔQ-expressing ddaC neurons (n = 26; Figures 3E, 3E′, and 3F), resembling the CBP RNAi phenotype. We did not recover MARCM ddaC clones using several CBP null/strong

hypomorphic alleles, which was consistent with a previous finding that CBP is essential for cell viability in the eye discs ( Kumar et al., 2004). Further, overexpression of the first exon of mutant Huntingtin (Httex1), with an expanded polyglutamine repeat (Httex1p-Q93; Steffan et al., 2001) that has been reported to sequestrate CBP protein and abolish its HAT activity in both flies and mammals, also resulted in a strong pruning defect (n = 7; Figure S3B) and loss of CBP VRT752271 mw protein (n = 13; Figure S3C) in ddaC neurons. About 13.8 primary and secondary dendrites remained connected in Httex1p-Q93-overexpressing ddaC neurons, whereas all dendrites were pruned in the Httex1p-Q20-overexpressing control ( Figure S3B). Similar to Brm, CBP appears to not be crucial for the development of major larval ddaC dendrites, because RNAi knockdown of CBP did not obviously affect the number of their primary and secondary dendrites of WP ddaC neurons

( Figures 3B–3D). CBP null mutant (nej3) ddaC neurons exhibited normal outgrowth of their embryonic dendrites at 17–18 hr APF (n = 24) and normal major dendrites with slightly simple terminals at 18–19 hr APF (n = 23), compared to the controls (n = 26 and n = 28, respectively; Figure S3E). The expression levels of Thymidine kinase Cut and Knot (n = 4 and n = 7, respectively; Figure S3F) were not affected in CBP RNAi ddaC neurons. Finally, CBP knockdown did not affect regrowth of ddaC dendrites at 76 hr APF (n = 11; Figure S3G). However, the involvement of CBP in dendritic morphology/connectivity of adult ddaCs remains unknown. In summary, CBP appears to be a specific HAT required for ddaC dendrite pruning during the larval-to-pupal transition. Both dendrite pruning of ddaD/E neurons and apoptosis of ddaF neurons are also dependent on EcR-B1 and Sox14 functions (Kirilly et al., 2009 and Williams and Truman, 2005a).

An elegant study has identified glycogen synthase kinase 3β (GSK3β) as a proline-directed kinase that controls phosphorylation- and proteolytic cleavage-induced turnover of gephyrin (Figure 5A) (Tyagarajan et al., 2011). Using tandem mass spectrometry of gephyrin, the authors identified

Idelalisib cost S270 as a residue that is basally phosphorylated in brain tissue. Transfection of cultured neurons with phosphorylation-deficient gephyrinS270A increased the density of gephyrin clusters and the amplitude and frequency of GABAergic mIPSCs, indicating that gephyrin clustering is limited by phosphorylation at S270. However, mutations of S270 had no effect on cluster size. Using kinase-specific inhibitors in in vitro phosphorylation assays the authors identified GSK3β as an important kinase for S270. To address the mechanism by which phosphorylation might increase gephyrin turnover they focused on calpain-1. This Ca2+-dependent cysteine protease was previously shown to cleave gephyrin and to produce a stable C-terminal gephyrin fragment of 48–50 kDa (Kawasaki et al., 1997). Transfection of neurons with the natural calpain-1

inhibitor calpastatin increased the gephyrin cluster density (Tyagarajan et al., 2011). Moreover, this effect was enhanced in the presence of the phosphomimetic mutant gephyrinS270E as a substrate, indicating that calpain-1-mediated degradation of gephyrin is triggered by phosphorylation

of S270. Lastly, the authors showed that S270 phosphostate-dependent clustering of gephyrin is enhanced mTOR inhibitor drugs by chronic treatment of cultured neurons or mice with Li+, a potent inhibitor of GSK3β used as mood-stabilizing agent for the no treatment of bipolar disorder. The findings strongly suggest that Li+-induced enhancement of GABAergic synaptic transmission contributes to the mood-stabilizing effects of Li+ in patients (Tyagarajan and Fritschy, 2010). GSK3β is inhibited as a downstream target of both the canonical Wnt signaling pathway (Inestrosa and Arenas, 2010) and the insulin receptor signaling pathway. Both pathways promote the postsynaptic clustering of GABAARs by additional, gephyrin-independent mechanisms, as detailed further below. Gephyrin forms a stable complex with affinity-purified glycine receptors (Pfeiffer et al., 1982). By contrast, GABAARs in detergent-solubilized membrane extracts do not stably associate with gephyrin (Meyer et al., 1995). Moreover, a major subset of GABAARs comprising α1βγ2 receptors can accumulate and cluster at synapses independently of gephyrin (Kneussel et al., 2001 and Lévi et al., 2004). Nevertheless, in brain gephyrin serves as a reliable postsynaptic marker for all GABAergic synapses (Sassoè-Pognetto et al., 1995, Essrich et al., 1998 and Sassoè-Pognetto and Fritschy, 2000).

“
“The influential

two-process model of sleep regulation posits that sleep pressure (i.e., the internal drive to sleep) is regulated by the interaction of circadian and homeostatic processes (Borbély, 1982). In this model, the circadian process synchronizes sleep drive to the 24 hr day-night cycle, while the homeostatic process steadily builds sleep pressure in response to wakefulness, then dissipates this pressure during sleep. Normally working in concert, the homeostatic process can be decoupled from the circadian process by sleep deprivation; as wakefulness is extended beyond normal physiological amounts, sleep pressure will also continue to build until it is homeostatically “reset” by subsequent rebound sleep. Although the mechanisms for coupling the circadian process to downstream sleep output remain murky, work in Drosophila and rodents over the past 40 years has painted a detailed picture this website of both the core molecular machinery (e.g., interlocking feedback loops among circadian clock proteins) as well as the critical pacemaker neurons (e.g., lateral

neurons in Drosophila, Tofacitinib datasheet the suprachiasmatic nucleus in mammals). Meanwhile, the homeostatic regulation of sleep is still shrouded in mystery. What aspects of prolonged waking drive sleep need? What are the molecular substrates by which this signal is transmitted? Where in the brain do these signals work to drive changes in sleep behavior? Some progress see more has been made in identifying critical sleep-wake circuits. In the mammalian hypothalamus, sleep-active GABAergic neurons

of the ventrolateral preoptic area (VLPO) form reciprocal inhibitory connections with a diverse set of wake-promoting neurons, known as the ascending arousal system (Saper et al., 2010). These circuits are considered critical drivers of sleep and wake, as ablation of the VLPO in rodents leads to insomnia, while pharmacological or optogenetic activation of components of the ascending arousal system promote waking (Rihel and Schier, 2013). An analogous sleep-wake circuit has recently been discovered in Drosophila. When directly activated by temperature-sensitive Trp channels, a set of neurons that project to the dorsal fan-shaped body (FB) induce sleep ( Donlea et al., 2011). These neurons are directly connected to and inhibited by wake-promoting, FB-projecting dopaminergic neurons via the dopamine receptor DopR. Curiously, both the mammalian VLPO and the Drosophila FB sleep neurons are sensitive to the anesthetic isoflurane, and, at least in flies, this sensitivity is increased with sleep deprivation ( Rihel and Schier, 2013). Given the central role that these neurons play as drivers of sleep/wake behavior, a natural hypothesis is that they will ultimately be sensitive, directly or indirectly, to the signal(s) of homeostatic sleep pressure.

Our in vivo experiment delivers CO2 in a physiological context, and indicates that proper localization of the RTN to the highly vascularized ventral brainstem surface (where chemosensitive Dabrafenib concentration astrocytes reside) ( Gourine et al., 2010) is critical for adult chemoresponsiveness. Whether the blunted chemosensitivity in the adult mouse is due to cell-autonomous deficits in RTN neurons and/or their displacement away from the ventral surface vascular bed and chemosensitive astrocytes is unknown. Furthermore, it is interesting to note that adult mice conditionally expressing the CCHS-causing PHOX2B mutation in the Egr-2 domain also show a partially impaired

hypercapnic response and hypersensitivity to hypoxia due to increased synaptic input from the carotid bodies ( Ramanantsoa et al., 2011). This crosstalk between central and peripheral chemosensory systems warrants further investigation, as disturbance in blood gas homeostasis and failure to arouse from sleep are serious detriments to health. Several bHLH transcription factors have emerged as disease-defining genes or genetic modifiers for neonatal respiratory disorders. Mutations in the transcription factor 4 (TCF4, an Atoh1-interacting bHLH factor) cause Pitt-Hopkins syndrome, which manifests SCH-900776 with infantile-onset hyperventilation ( Amiel et al., 2007). Heterozygous nucleotide substitutions

in human achaete-scute homolog-1 of CCHS patients have been uncovered and might impair noradrenergic neural development Cytidine deaminase ( de Pontual et al., 2003). Both TCF4 and achaete-scute homolog-1 null mice die during the newborn period because of unknown breathing and feeding defects ( Guillemot et al., 1993; Zhuang et al., 1996). In light of these dramatic phenotypes, studying conditional mutants of these bHLH factors will facilitate the identification of additional neuronal structures that ensure proper respiratory activity in the

early postnatal life. In sum, we provide direct evidence that the expression of Atoh1 in the postmitotic RTN neurons during fetal hindbrain development serves as an intrinsic signal that guides proper neuronal migration and projection, which is a critical step to stimulate inspiratory rhythm at birth. Selective loss of paramotor Atoh1 expression compromises neonatal breathing and adult hypercapnic response. These findings provide an example of how transient expression of a bHLH transcription factor shapes the physiological function of postmitotic neurons and provide insights into the developmental assembly of respiratory network that might be altered in neonatal respiratory disorders. Moreover, these data suggest that early developmental abnormalities, if survived, have an impact on physiological responses and respiratory health in adults. Animal housing, husbandry, and euthanasia were conducted under the guidelines of the Center for Comparative Medicine, Baylor College of Medicine.

As NotI digests were typically used during the former era of EST discovery, the 5′ end of this transcript was likely created during its cloning. To identify the extent of the antisense transcript, we performed strand-specific RT-PCR and 5′ RACE, and mapped the TSS to intron 4 (Figure 2A). We named this antisense transcript SCAANT1 for “spinocerebellar ataxia-7 antisense noncoding transcript 1.” To delineate the regulatory region responsible for transcription of SCAANT1, we cloned a series of human ataxin-7 CAG10 genomic fragments into a luciferase reporter construct in antisense orientation Selleckchem Alpelisib ( Figure 2A) and transfected the different ataxin-7 antisense genomic fragment—luciferase

constructs into primary cerebellar astrocytes. We noted that a short stretch of DNA 5′ to the SCAANT1 TSS was required for transactivation, while a sizable sequence 3′ to the SCAANT1 TSS was needed to achieve robust

Screening Library order transactivation ( Figure 2B). As the two CTCF binding sites lie within the regulatory domain mapped by the luciferase reporter assays, we derived another set of luciferase reporter constructs, based upon our most potent construct 2R, in which we mutated either of the CTCF binding sites ( Figure 2A). When we measured the transactivation competence of the 2R-m2 and 2R-m1 constructs, we observed marked reductions in luciferase activity ( Figure 2B), suggesting that CTCF binding site integrity is required for maximal SCAANT1 expression. We also derived an ataxin-7 antisense construct carrying a CAG92 repeat expansion (2R-exp), and when we measured its transactivation competence, we documented a significant reduction in luciferase activity ( Figure 2B). The existence of an ∼1.4 kb antisense noncoding transcript overlapping Thalidomide a potentially strong sense promoter at the human ataxin-7 locus suggested that their transcription regulation might be linked. As CTCF binding site integrity was required for SCAANT1

transcription, we derived two ataxin-7 minigene constructs that contain the sense P2A promoter and SCAANT1, flanked by ∼5 kb of DNA 5′ to this region and ∼8 kb of DNA 3′ to this region (Figure S2). Within this 13.5 kb human ataxin-7 genomic fragment reside two CTCF binding sites, known as CTCF-I and CTCF-II. To understand the regulatory relationship between SCAANT1 and ataxin-7 transcription from promoter P2A, we introduced an 11 nucleotide substitution mutation at the 3′ CTCF-I binding site (Figure S2). The location of the mutation was based upon DNA footprinting analysis, and validation of abrogated CTCF binding was achieved by electrophoretic mobility shift assays, as we have shown (Libby et al., 2008). In this way, we derived two distinct ataxin-7 genomic fragment constructs with an expanded CAG repeat tract: SCA7-CTCF-I-wt and SCA7-CTCF-I-mut (Figure S2).

0.6–1.5 log10 CFU/g mL in general experimental conditions. Microbial reduction by ultrasound is very important from the stand point of green decontamination and the hurdle concept of inhibition and elimination methods for food ISRIB datasheet preservation technologies in fruits and vegetables. Additionally, from existing literature we concluded that

these results could be helpful for estimating the decontamination effect of ultrasound and the possible use of ultrasound technology in different processes instead of antimicrobial chemical agents in fruits and vegetable washing processes. Until today, the results obtained from different studies carried out using decontamination washing treatments combined with ultrasound applications are variable. Findings from different studies are also difficult to compare because they use different parameters such as ultrasound frequency, efficiency, acoustic energy density, time of treatment, temperature, water/sample ratios, agitation-washing protocol, species and strains of test organisms such as E. coli O157:H7, S. typhimurium, L. monocytogenes, and type of fruits and vegetables. There are a lot of parameters and factors which are not interpreted the same in all experimental conditions. Because of these differences, the harmonization of the results Screening Library clinical trial of

the ultrasound applications may be very difficult. As a result, finding the best conditions, doses, and combination of treatments for different hurdle decontamination technologies is a further challenge for the commercial adaptation of ultrasound. Future studies are needed to use ultrasound technology for decontamination purposes in the commercial food industry in place, for the purpose of scale up and optimization. These realistic studies are the only way to determine the best operating conditions. It was also shown that, ultrasound applied by itself and with the chemical agents chlorine, peroxyacetic acid, and acidic electrolyzed water showed no significant microbial reduction (approx. 1 log CFU/g) between the two processes. In light of this knowledge,

future research is necessary to determine the antimicrobial effects using ultrasound or chemicals in order to compare the results for decontamination washing processes Terminal deoxynucleotidyl transferase in the fruit and vegetable industries. “
“Many foods form ideal substrates for the growth of fungi, both yeasts and moulds, due to their carbohydrate, protein and vitamin content. If left untreated, fungal growth will result in spoilage, due to alterations in visual appearance, texture, taste, aroma, and the formation of fungal biomass and in some cases, a variety of mycotoxins. In order to prevent microbial spoilage, many foods are sterilised using heat, while others are treated with preservatives of proven safety of which the great majority are weak-acids. Soft drinks may contain limited concentrations of sorbic acid (2,4-hexadienoic acid) or benzoic acid (Anon.