Increased Sensitivity To Cold Research Articles

MaHsf24, a novel negative modulator, regulates cold tolerance in banana fruits by repressing the expression of HSPs and antioxidant enzyme genes

SummaryTranscriptional regulation mechanisms underlying chilling injury (CI) development have been widely investigated in model plants and cold‐sensitive fruits, such as banana (Musa acuminata). However, unlike the well‐known NAC and WRKY transcription factors (TFs), the function and deciphering mechanism of heat shock factors (HSFs) involving in cold response are still fragmented. Here, we showed that hot water treatment (HWT) alleviated CI in harvested banana fruits accomplishing with reduced reactive oxygen species (ROS) accumulation and increased antioxidant enzyme activities. A cold‐inducible but HWT‐inhibited HSF, MaHsf24, was identified. Using DNA affinity purification sequencing (DAP‐seq) combined with RNA‐seq analyses, we found three heat shock protein (HSP) genes (MaHSP23.6, MaHSP70‐1.1 and MaHSP70‐1.2) and three antioxidant enzyme genes (MaAPX1, MaMDAR4 and MaGSTZ1) were the potential targets of MaHsf24. Subsequent electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation coupled with quantitative PCR (ChIP‐qPCR) and dual‐luciferase reporter (DLR) analyses demonstrated that MaHsf24 repressed the transcription of these six targets via directly binding to their promoters. Moreover, stably overexpressing MaHsf24 in tomatoes increased cold sensitivity by suppressing the expressions of HSPs and antioxidant enzyme genes, while HWT could recover cold tolerance, maintaining higher levels of HSPs and antioxidant enzyme genes, and activities of antioxidant enzymes. In contrast, transiently silencing MaHsf24 by virus‐induced gene silencing (VIGS) in banana peels conferred cold resistance with the upregulation of MaHSPs and antioxidant enzyme genes. Collectively, our findings support the negative role of MaHsf24 in cold tolerance, and unravel a novel regulatory network controlling bananas CI occurrence, concerning MaHsf24‐exerted inhibition of MaHSPs and antioxidant enzyme genes.

VvERF117 positively regulates grape cold tolerance through direct regulation of the antioxidative gene BAS1

Cold stress significantly threatens grape quality, yield, and geographical distribution. Although ethylene-responsive factors (ERFs) are recognized for their pivotal roles in cold stress, the regulatory mechanisms of many ERFs contributing to tolerance remain unclear. In this study, we identified the cold-responsive gene VvERF117 and elucidated its positive regulatory function in cold tolerance. VvERF117 exhibits transcriptional activity and localizes to the nucleus. VvERF117 overexpression improved cold tolerance in transgenic Arabidopsis, grape calli, and grape leaves, whereas VvERF117 silencing increased cold sensitivity in grape calli and leaves. Furthermore, VvERF117 overexpression remarkably upregulated the expression of several stress-related genes. Importantly, BAS1, encoding a 2-Cys peroxidase (POD), was confirmed as a direct target gene of VvERF117. Meanwhile, compared to the wild-type, POD activity and H2O2 content were remarkably increased and decreased in VvERF117-overexpressing grape calli and leaves, respectively. Conversely, VvERF117 silencing displayed the opposite trend in grape calli and leaves under cold stress. These findings indicate that VvERF117 plays a positive role in cold resistance by, at least in part, enhancing antioxidant capacity through regulating the POD-encoding gene VvBAS1, leading to effective mitigation of reactive oxygen species.

Intervertebral disc human nucleus pulposus cells associated with back pain trigger neurite outgrowth in vitro and pain behaviors in rats.

Low back pain (LBP) is often associated with the degeneration of human intervertebral discs (IVDs). However, the pain-inducing mechanism in degenerating discs remains to be elucidated. Here, we identified a subtype of locally residing human nucleus pulposus cells (NPCs), generated by certain conditions in degenerating discs, that was associated with the onset of discogenic back pain. Single-cell transcriptomic analysis of human tissues showed a strong correlation between a specific cell subtype and the pain condition associated with the human degenerated disc, suggesting that they are pain-triggering. The application of IVD degeneration-associated exogenous stimuli to healthy NPCs in vitro recreated a pain-associated phenotype. These stimulated NPCs activated functional human iPSC-derived sensory neuron responses in an in vitro organ-chip model. Injection of stimulated NPCs into the healthy rat IVD induced local inflammatory responses and increased cold sensitivity and mechanical hypersensitivity. Our findings reveal a previously uncharacterized pain-inducing mechanism mediated by NPCs in degenerating IVDs. These findings could aid in the development of NPC-targeted therapeutic strategies for the clinically unmet need to attenuate discogenic LBP.

Vibration related symptoms and signs in two groups of exposed workers

The aim was to compare the prevalence of vibration related symptoms and signs in two groups of vibration exposed male workers: 36 vibration exposed patients and 33 truck mechanics. All participants answered a questionnaire, passed a structured interview about work and medical history and several neurophysiological tests. The prevalence of vibration white fingers (VWF) and neurosensory symptoms was significantly higher among the exposed patients than among the truck mechanics. One neurosensory examination method identified 46% of the exposed patients with numbness and tingling, three methods up to 85%. In the total material logistic regression showed that age and increased cold sensitivity were significant predictors of both neurosensory disturbances and vibration white fingers. Muscle cramps in arms and hands, pain in hands and age were significant predictors of reduced grip strength. The differences between the two groups were more pronounced for category variables than for continuous variables.

PhDREB1-PhZFP1-PhGolS1-1 regulator cascade contribute to cold tolerance by mediating galactinol and raffinose accumulation in petunia

The C-repeat/DRE Binding Factor (CBF/DREB1) gene, which plays a critical role in plant responses to cold stress, could positively regulate the accumulation of galactinol and raffinose, but the underlying molecular mechanisms remain elusive. We have previously confirmed that the C2H2-type zinc finger protein PhZFP1 plays a positive role in cold stress tolerance by modulating galactinol accumulation by directly regulating PhGolS1-1 in Petunia hybrida. However, whether and how CBF/DREB1 regulates PhZFP1 to mediate galactinol accumulation under cold stress remains largely unclear. Here, we report the biological and molecular characterization of PhDREB1F and PhDREB1I in petunia. We demonstrate that PhDREB1F and PhDREB1I function as nuclear transcription factors and activate PhZFP1 expression. Silencing of PhDREB1F or PhDREB1I mediated by virus-induced gene silencing (VIGS) increased the sensitivity to freezing stress in petunia plants. Besides, knocking-down of PhDREB1F or PhDREB1I decreased the expression of PhZFP1 and PhGolS1-1. Similarly, silencing of PhGolS1-1 increased cold sensitivity in petunia. And the contents of galactinol and raffinose in PhGolS1-1-VIGS plants were significantly decreased compared with those in TRV plants under chilling stress. What's more, PhDREB1F/1I, PhZFP1, and PhGolS1-1 all showed cold-induced expression patterns with different peaks. Collectively, our data indicate that PhDREB1F and PhDREB1I positively modulate cold stress tolerance through the PhDREB1s-PhZFP1-PhGolS1–1 pathway in petunia. This study provides new insights into the molecular mechanism of plant responsiveness to cold stress through CBF/DREB1 transcription factors.

Jasmonate Positively Regulates Cold Tolerance by Promoting ABA Biosynthesis in Tomato.

As a cold-sensitive species, tomato is frequently challenged by cold stress during vegetative and reproductive growth. Understanding how tomato responds to cold stress is of critical importance for sustainable tomato production. In this work, we demonstrate that jasmonate (JA) plays a crucial role in tomato response to cold stress by promoting abscisic acid (ABA) biosynthesis. It was observed that both JA and ABA levels were substantially increased under cold conditions, whereas the suppression of JA biosynthesis abated ABA accumulation. The ABA biosynthesis gene 9-CIS-EPOXYCAROTENOID DIOXYGENASE2 (NCED2) was subsequently found to be associated with JA-mediated ABA biosynthesis in tomato plants in response to cold stress. NCED2 was rapidly induced by exogenous MeJA and cold treatment. Silencing NCED2 led to a decrease in ABA accumulation that was concurrent with increased cold sensitivity. Moreover, blocking ABA biosynthesis using a chemical inhibitor impaired JA-induced cold tolerance in tomato. Furthermore, MYC2, a core component of the JA signaling pathway, promoted the transcription of NCED2, ABA accumulation and cold tolerance in tomato. Collectively, our results support that JA signaling promotes ABA biosynthesis to confer cold tolerance in tomato.

Breathe and burn: Novel roles for myoglobin in thermogenesis

Breathe and burn: Novel roles for myoglobin in thermogenesis

Inhibitory Kcnip2 neurons of the spinal dorsal horn control behavioral sensitivity to environmental cold

Proper sensing of ambient temperature is of utmost importance for the survival of euthermic animals, including humans. While considerable progress has been made in our understanding of temperature sensors and transduction mechanisms, the higher-order neural circuits processing such information are still only incompletely understood. Using intersectional genetics in combination with circuit tracing and functional neuron manipulation, we identified Kcnip2-expressing inhibitory (Kcnip2GlyT2) interneurons of the mouse spinal dorsal horn as critical elements of a neural circuit that tunes sensitivity to cold. Diphtheria toxin-mediated ablation of these neurons increased cold sensitivity without affecting responses to other somatosensory modalities, while their chemogenetic activation reduced cold and also heat sensitivity. We also show that Kcnip2GlyT2 neurons become activated preferentially upon exposure to cold temperatures and subsequently inhibit spinal nociceptive output neurons that project to the lateral parabrachial nucleus. Our results thus identify a hitherto unknown spinal circuit that tunes cold sensitivity.

In Vitro Pain Assay Using Human iPSC-Derived Sensory Neurons and Microelectrode Array.

Drug-induced peripheral neuropathy occurs as an adverse reaction of chemotherapy. However, a highly accurate method for assessing peripheral neuropathy and pain caused by compounds has not been established. The use of human-induced pluripotent stem cell (hiPSC)-derived sensory neurons does not require animal experiments, and it is considered an effective method that can approach extrapolation to humans. In this study, we evaluated the response to pain-related compounds based on neural activities using in vitro microelectrode array (MEA) measurements in hiPSC-derived sensory neurons. Cultured sensory neurons exhibited gene expression of the Nav1.7, TRPV1, TRPA1, and TRPM8 channels, which are typical pain-related channels. Channel-dependent evoked responses were detected using the TRPV1 agonist capsaicin, a TRPA1 agonist, allyl isothiocyanate (AITC), and TRPM8 agonist menthol. In addition, the firing frequency increased with an increase in temperature from 37°C to 46°C, and temperature sensitivity was observed. In addition, the temperature of the peak firing rate differed among individual neurons. Next, we focused on the increase in cold sensitivity, which is a side effect of the anticancer drug oxaliplatin, and evaluated the response to AITC in the presence and absence of oxaliplatin. The response to AITC increased in the presence of oxaliplatin in a concentration-dependent manner, suggesting that the increased cold sensitivity in humans can be reproduced in cultured hiPSC-derived sensory neurons. The in vitro MEA system using hiPSC-derived sensory neurons is an alternative method to animal experiments, and it is anticipated as a method for evaluating peripheral neuropathy and pain induced by compounds.

Net photosynthesis acclimates to low growth temperature in cotton seedlings by shifting temperature thresholds for photosynthetic component processes and respiration

Temperatures between 10 °C and 25 °C limit seedling growth and reversibly inhibit net assimilation (AN) in cold-sensitive plants. Because AN represents multiple component processes operating in a highly concerted manner, quantifying the cold sensitivities of each constituent would provide targets for improving cold tolerance. To address this, Gossypium hirsutum (cotton) seedlings grown under sub-optimal temperatures (20/15 °C) exhibited substantial declines in plant growth, AN, and nearly every thylakoid process assessed, relative to optimal conditions (30/20 °C). In contrast, energy dissipation by photosystem II (PSII) increased under low temperature concomitant with a rise in carotenoid content, hydrogen peroxide production, and ascorbate peroxidase activity. Temperature response experiments defined the temperature needed for 50% reductions in activity for a given process (T50). Respiration (RD) was the most cold-sensitive process followed by thylakoid-dependent processes and gross photosynthesis (AG), whereas AN was the most-cold tolerant process evaluated. AN-Ci experiments revealed that carboxylation was more cold-sensitive than RuBP regeneration. Maximum quantum yield of photosystem II was insensitive to low incubation temperature (Fv/Fm), and T50 could not be estimated. Low temperature-grown plants also exhibited a 1.5 °C increase in T50 for RD, a 2.5 °C decrease in T50 for thylakoid-dependent processes and AG, and a 3.4 °C decrease in T50 for AN. Thus, the current study defines the relative cold sensitivities of the underlying processes driving AN. Additionally, it is concluded that AN acclimates to low growth temperature more than any other process evaluated due to increased cold sensitivity of RD and increased cold tolerance of thylakoid dependent processes and AG.

First Report of Apple rubodvirus 2 Infecting Pear (Pyrus communis) in South Africa.

Apple rubbery wood virus 2 (ARWV-2; Rott et al., 2018) belong to the species Apple rubodvirus 2, a member of the genus Rubodvirus (family Phenuiviridae; Kuhn et al 2020). ARWV-2 was first identified in apples and is associated with apple rubbery wood disease (ARWD) that is characterized by unusual flexibility of stems and branches, reduced growth, shortened internodes and increased cold sensitivity (Jakovljevic et al., 2017, Rott et al., 2018). ARWD was first reported in 1935 in England on apple and has since been found on quince and pear (Jakovljevic et al., 2017; Rott et al., 2018). In January 2021, leaves were collected from a pear tree (Pyrus communis cv. Forelle, F514) in a commercial orchard near Villiersdorp, South Africa. The tree displayed no foliar or tree branch symptoms, except for malformed fruits potentially due to insect feeding damage or pear stony pit disease previously associated with infection of apple stem pitting virus (ASPV) (Paunovic et al. 1999). Leaf petioles (one gram) were used for total RNA extraction, using a modified CTAB extraction protocol (Ruiz-García et al. 2019). A sequencing library was constructed (Illumina TruSeq Stranded Total RNA with plant Ribo-Zero) and sequenced on an Illumina HiseqX instrument (Macrogen, South Korea). A total of 30,709,182 paired-end reads (100 nt) were obtained and trimmed for quality with Trimmomatic (SLIDINGWINDOW:3:20, MINLEN:20) (Bolger et al. 2014). De novo assembly, using default parameters of CLC Genomics Workbench 11.0.1 (Qiagen), resulted in 97,294 contigs. BLASTn analysis identified 17 viral contigs, with 14 contigs having high nucleotide identity to ASPV and three to ARWV-2. The latter contigs included all three segments of ARWV-2. The L contig was 7371 nts, M was 1289 nts and S was 1463 nts in length, generated with 7341, 626 and 9161 reads for segment L, M and S, respectively. Segment S had the highest read coverage (524.87x), followed by segment L (88.07x) and M (36.60x). The ARWV-2 GenBank accessions with the highest percentage identity to the contigs were MF062128.1 from United States of America (98.2% to segment L), MN163134.1 from China (97.5% to segment M) and NC_055535.1 from Germany (93.5% to segment S). The contigs spanned 100%, 80.92% and 100% of these accessions of segments L, M and S, respectively and were deposited in GenBank as accessions MZ593725- MZ593727. Reverse transcription polymerase chain reaction (RT-PCR) was used to validate the presence of ARWV-2 in sample F514, using primers directed at segments L (con708_178F/con708_666R), M (ARWaV-2S1_38F/ARWaV-2S1_682R) and S (ARWaV-2M567F/ARWaV-2M1342R) (Rott et al., 2018). Amplicon sequences (510 bp (L), 645 bp (M) and 799 bp (S)) were confirmed with bi-directional Sanger sequencing. Fifty-nine additional pear samples were surveyed in 2021 for ARWV-2 using the M segment assay as mentioned above. The survey included the Koue Bokkeveld and Elgin areas, and cultivars Bosc (22 samples), Abate (10 samples), Rosemarie (3 samples), Forelle (9 samples), Packham's Triumph (12 samples) and Early Bon Chretien (3 samples). A total of 27 samples (11 samples from the Koue Bokkeveld region and 16 samples from the Elgin region) tested positive for ARWV-2, demonstrating the common presence of this virus in pears in South Africa. This is the first report of ARWV-2 infecting pear in South Africa. Although no association with disease symptoms were observed, this study expands the data on the incidence and distribution of this virus in South Africa.

Efficacy of targeted muscle reinnervation is directly affected by timing of intervention in a neuropathic pain model

Purpose Targeted muscle reinnervation (TMR) coapts amputated nerves to small motor nerves to power a prosthetic limb. Additionally, clinical studies have shown TMR performed within 3 months of major limb amputation prevents or reduces phantom and residual limb pain. However, TMR delayed over 3 months is much less effective. We have previously shown that TMR performed 3 weeks following SNI returned pain behaviors to baseline. This study examined the effect of TMR performed at the time of TMR versus a delay of 12 weeks following SNI to determine whether this model reflects clinical findings. SNI was performed in male rats and interventions were applied at the time of SNI, 3 weeks, and 12 weeks following SNI. Pain behaviors were assessed with von Frey threshold, pin testing, dynamic brush testing and acetone testing prior to intervention and at 1, 3, 6, and 12 weeks following intervention. Simple neuroma excision (NE) was used as a control intervention. TMR performed immediately at the time of SNI prevented the development of a pain phenotype. Animals tested 3 and 12 weeks following SNI showed a robust pain phenotype: increased hyperalgesic responses, reduced Von Frey thresholds, and increased cold sensitivity. TMR at 3 weeks following SNI successfully reversed the pain behaviors to baseline. In contrast, if TMR or NE was delayed 12 weeks after SNI, the pain behaviors persisted. The neuropathic pain phenotype generated by SNI can be treated with TMR performed immediately and 3 weeks following development of a pain phenotype. In contrast, delayed TMR provides no relief of pain behaviors. This model closely corresponds to clinical experience in patients with limb amputation and will facilitate further understanding of the mechanisms behind TMR and how the intervention may be modified to help chronic amputation-related pain. Medical College of Wisconsin Neurosciences Research Center Plastic Surgery Foundation- American Association for Hand Surgery Pilot Grant 628811.

The phytochrome-interacting transcription factor CsPIF8 contributes to cold tolerance in citrus by regulating superoxide dismutase expression

As one of the subtropical and tropical fruit trees, Citrus sinensis is sensitive to cold stress. However, most transcription factors (TFs) that regulate cold tolerance in citrus have not yet been reported. A phytochrome-interacting transcription factor (PIF) gene (CsPIF8) in citrus was significantly upregulated under cold stress. Overexpression of CsPIF8 increased cold tolerance in transgenic tomato plants and grapefruit callus, whereas virus-induced gene silencing-mediated suppression of PIF8 increased cold sensitivity in seedlings of Poncirus trifoliata. Superoxide dismutase (SOD) reduces the superoxide anion (O2−) level to enhance cold tolerance in plants. Chromatin immunoprecipitation combined with high-throughput sequencing, yeast one hybrid, electrophoretic mobility shift and dual luciferase assays showed that CsPIF8 directly bound the E-box (CANNTG) of CsSOD promoter and activated the promoter of CsSOD. Furthermore, the expression level of CsSOD and CsSOD activity were significantly increased, whereas the level of O2− was significantly reduced in the transgenic lines. The Poncirus trifoliata seedlings with VIGS-mediated suppression of PIF8 exhibited the opposite effects. These results have shown that CsPIF8 improved cold tolerance in citrus through regulating the expression level of SOD and SOD activity. These findings may provide novel insights into the regulation of PIF8 in the response to cold stress in citrus.

Association of quantitative sensory testing parameters with clinical outcome in patients with lumbar radiculopathy undergoing microdiscectomy.

Background/AimThis study aimed to establish the somatosensory profile of patients with lumbar radiculopathy at pre‐and post‐microdiscectomy and to explore any association between pre‐surgical quantitative sensory test (QST) parameters and post‐surgical clinical outcomes.MethodsA standardized QST protocol was performed in 53 patients (mean age 38 ± 11 years, 26 females) with unilateral L5/S1 radiculopathy in the main pain area (MPA), affected dermatome and contralateral mirror sites and in age‐ and gender‐,and body site‐matched healthy controls. Repeat measures at 3 months included QST, the Oswestry Disability Index (ODI) and numerous other clinical measures; at 12 months, only clinical measures were repeated. A change <30% on the ODI was defined as ‘no clinically meaningful improvement’.ResultsPatients showed a significant loss of function in their symptomatic leg both in the dermatome (thermal, mechanical, vibration detection p < .002), and MPA (thermal, mechanical, vibration detection, mechanical pain threshold, mechanical pain sensitivity p < .041) and increased cold sensitivity in the MPA (p < .001). Pre‐surgical altered QST parameters improved significantly post‐surgery in the dermatome (p < .018) in the symptomatic leg and in the MPA (p < .010), except for thermal detection thresholds and cold sensitivity. Clinical outcomes improved at 3 and 12 months (p < .001). Seven patients demonstrated <30% change on the ODI at 12 months. Baseline loss of function in mechanical detection in the MPA was associated with <30% change on the ODI at 12 months (OR 2.63, 95% CI 1.09–6.37, p = .032).ConclusionMicrodiscectomy resulted in improvements in affected somatosensory parameters and clinical outcomes. Pre‐surgical mechanical detection thresholds may be predictive of clinical outcome.SignificanceThis study documented quantitative sensory testing (QST) profiles in patients with lumbar radiculopathy in their main pain area (MPA) and dermatome pre‐ and post‐microdiscectomy and explored associations between QST parameters and clinical outcome. Lumbar radiculopathy was associated with loss of function in modalities mediated by large and small sensory fibres. Microdiscectomy resulted in significant improvements in loss of function and clinical outcomes in 85% of our cohort. Pre‐surgical mechanical detection thresholds in the MPA may be predictive of clinical outcome.

Resolution of Hypothyroidism Restores Cold-Induced Thermogenesis in Humans.

Background: Hypothyroidism is a frequent endocrine disorder with common symptoms of increased cold sensitivity and unintended weight gain, indicating changes in energy expenditure (EE) and response to cold exposure. Thyroid hormones (TH) play an important role for proper function of brown adipose tissue (BAT) and cold-induced thermogenesis (CIT) in rodents, but the role of hypothyroidism on CIT in humans is uncertain.Methods: This was a prospective observational study. Forty-two patients presenting with subclinical or overt hypothyroidism in whom TH replacement was planned were recruited. Thirty-three patients completed the study. Thermogenesis was measured by indirect calorimetry during warm conditions and after a mild cold stimulus of 90 minutes, both during the hypothyroid state and after at least three months of sufficient TH replacement. CIT was determined as the difference between EE during mildly cold and warm conditions. The primary endpoint was the change of CIT between the hypothyroid and euthyroid state.Results: EE during warm conditions increased from a median of 1330 (interquartile range [IQR] 1251–1433) kcal/24 hours in the hypothyroid state to a median of 1442 (IQR 1294–1579) kcal/24 hours in the euthyroid state (+8.5%; p = 0.0002). EE during mild cold exposure increased from 1399 (IQR 1346–1571) kcal/24 hours to 1610 (IQR 1455–1674) kcal/24 hours (+15%; p < 0.0001). The median CIT was 55 (IQR 1–128) kcal/24 hours at the baseline visit, after restoration of euthyroidism CIT increased by 102% to a median of 111 (IQR 15.5–200) kcal/24 hours (p = 0.011). Serum levels of free thyroxine at the respective visit and mean outdoor temperature during the preceeding 30 days were significantly associated with CIT (p = 0.021 and p = 0.001, respectively).Conclusion: Restoring euthyroidism significantly increases CIT in hypothyroid humans.

Sex Differences in a Rodent Model of HIV-1-Associated Neuropathic Pain.

Worldwide, women account for approximately 51% of human immunodeficiency virus-1 (HIV) seropositive individuals. The prevalence of neuropathic pain among individuals with HIV and a lack of preclinical data characterizing sex differences prompted us to address this knowledge gap. C57BL/6 male and female mice received multiple intrathecal injections of HIV-glycoprotein 120 (gp120), followed by determination of mechanical allodynia and thermal hypersensitivity for four weeks. The influence of ovarian hormones in the gp120 pain model was evaluated by comparison of ovariectomized (OVX) mice versus sham control. We found that gp120-induced neuropathic pain-like behaviors are sex-dependent. Female mice showed both increased mechanical allodynia and increased cold sensitivity relative to their male counterparts. The OVX mice showed reduced pain sensitivity compared to sham, suggesting a role of the ovarian hormones in sex differences in pain sensitivity to gp120. Gp120-induced neuropathic pain caused a shift in estrous cycle toward the estrus phase. However, there is a lack of clear correlation between the estrous cycle and the development of neuropathic pain-like behaviors during the four week recording period. This data provided the first evidence for sex differences in a rodent model of HIV-related neuropathic pain, along with a potential role of ovarian hormones.

Biomechanical response of the human foot when standing in a natural position while exposed to vertical vibration from 10–200 Hz

Exposure to foot-transmitted vibration (FTV) can lead to pain and numbness in the toes and feet, increased cold sensitivity, blanching in the toes, and joint pain. Prolonged exposure can result in a clinical diagnosis of vibration-induced white foot (VIWFt). Data on the biomechanical response of the feet to FTV is limited; therefore, this study seeks to identify resonant frequencies for different anatomical locations on the human foot, while standing in a natural position. A laser Doppler vibrometer was used to measure vertical (z-axis) vibration on 21 participants at 24 anatomical locations on the right foot during exposure to a sine sweep from 10–200 Hz with a peak vertical velocity of 30 mm/s. The most notable differences in the average peak frequency occur between the toes (range: 99–147 Hz), midfoot (range: 51–84 Hz) and ankle (range: 16–39 Hz).Practitioner Summary: The biomechanical response of the human foot exposed to foot-transmitted vibration, when standing in a natural position, was measured for 21 participants. The foot does not respond uniformly; the toes, midfoot, and ankle regions need to be considered independently in future development of isolation strategies and protective measures.

The OsMYB30 Transcription Factor Suppresses Cold Tolerance by Interacting with a JAZ Protein and Suppressing β-Amylase Expression.

Cold stress is one of the major limiting factors for rice (Oryza sativa) productivity. Several MYB transcriptional factors have been reported as important regulators in the cold stress response, but the molecular mechanisms are largely unknown. In this study, we characterized a cold-responsive R2R3-type MYB gene, OsMYB30, for its regulatory function in cold tolerance in rice. Functional analysis revealed that overexpression of OsMYB30 in rice resulted in increased cold sensitivity, while the osmyb30 knockout mutant showed increased cold tolerance. Microarray and quantitative real-time polymerase chain reaction analyses revealed that a few β-amylase (BMY) genes were down-regulated by OsMYB30. The BMY activity and maltose content, which were decreased and increased in the OsMYB30 overexpression and osmyb30 knockout mutant, respectively, were correlated with the expression patterns of the BMY genes. OsMYB30 was shown to bind to the promoters of the BMY genes. These results suggested that OsMYB30 exhibited a regulatory effect on the breakdown of starch through the regulation of the BMY genes. In addition, application of maltose had a protective effect for cell membranes under cold stress conditions. Furthermore, we identified an OsMYB30-interacting protein, OsJAZ9, that had a significant effect in suppressing the transcriptional activation of OsMYB30 and in the repression of BMY genes mediated by OsMYB30. These results together suggested that OsMYB30 might be a novel regulator of cold tolerance through the negative regulation of the BMY genes by interacting with OsJAZ9 to fine-tune the starch breakdown and the content of maltose, which might contribute to the cold tolerance as a compatible solute.

Effects of Macrophage Depletion on Sleep in Mice.

The reciprocal interaction between the immune system and sleep regulation has been widely acknowledged but the cellular mechanisms that underpin this interaction are not completely understood. In the present study, we investigated the role of macrophages in sleep loss- and cold exposure-induced sleep and body temperature responses. Macrophage apoptosis was induced in mice by systemic injection of clodronate-containing liposomes (CCL). We report that CCL treatment induced an immediate and transient increase in non-rapid-eye movement sleep (NREMS) and fever accompanied by decrease in rapid-eye movement sleep, motor activity and NREMS delta power. Chronically macrophage-depleted mice had attenuated NREMS rebound after sleep deprivation compared to normal mice. Cold-induced increase in wakefulness and decrease in NREMS, rapid-eye movement sleep and body temperature were significantly enhanced in macrophage-depleted mice indicating increased cold sensitivity. These findings provide further evidence for the reciprocal interaction among the immune system, sleep and metabolism, and identify macrophages as one of the key cellular elements in this interplay.

Regions 1.2 and 3.2 of the RNA Polymerase σ Subunit Promote DNA Melting and Attenuate Action of the Antibiotic Lipiarmycin

Initiation of RNA synthesis by bacterial RNA polymerase (RNAP) requires melting of promoter DNA, which is nucleated by the σ subunit during formation of the “open” promoter complex (RPo). The antibiotic lipiarmycin (Lpm) inhibits promoter melting by blocking access of the template DNA strand to the RNAP active-site cleft. Here we show that Escherichia coli RNAP holoenzymes containing either housekeeping σ70, with a deletion in the region 3.2, or the stationary phase σS subunits exhibited hypersensitivity to Lpm and increased cold sensitivity of RPo formation. Similar effects were produced by mutation located ~60Å away from the Lpm binding site within σ70 region 1.2, controlling −10 promoter element recognition. Our data suggested that template strand single-stranded DNA competes with Lpm for binding to RNAP and that σ70 regions 1.2 and 3.2 attenuate Lpm action by promoting DNA duplex opening.