Short Incubation Period Research Articles

Hepatic heat shock proteins, antioxidant-related genes, and immunocompetence of heat-stressed broilers in response to short periods of incubation during egg storage and thermal conditioning

Short Periods of Incubation During Egg Storage (SPIDES) approach improves chick quality and hatching rates. Also, embryonic thermal conditioning (TC) is a strategy for enhancing thermotolerance in avian species. Until now, evaluating the effect of either SPIDES or embryonic TC effects has only been separately conducted, so we hypothesized that combining TC and SPIDES may enhance the response of broilers to thermal stress. Eight hundred Ross broiler eggs were divided into two groups; the first one was kept under appropriate storage room conditions, S0 (control) The 2nd was subjected to SPIDES for 5 h at 37.8 ○C ± 0.1 three times at days 5, 10, and 15 (S1) after egg collection respectively. On the 14th day of incubation (DOI) each of the two main groups was randomly divided into two equal subgroups; the control one was left under the appropriate incubation settings (TC0) whereas the other received prenatal heat conditioning (TC1) at 39.5 ○C ± 0.1 for 6 h/d from the 14th to the 18th embryonic day (E), resulting finally in four experimental subgroups (S0TC0, S1TC0, S0TC1 & S1TC1). Resultsshowed that SPIDES treatment improved the hatchability of the stored eggs by almost 20% compared to untreated eggs. A combination of SPIDES and TC (S1TC1) increased significantly the levels of Immunoglobulin (IgG and IgM) production at hatch and heat-stressed birds. Our findings revealed that the hepatic heat shock proteins (hsp70, 90 A,90 B, 60 and hspA9), antioxidants-related genes (CAT, and SOD2), and NADPH4 were significantly downregulated in the thermally conditioned group that challenged with thermal stress conditions. As opposed to that, the SPIDES group showed a significant increase in hepatic heat shock proteins, antioxidants-related genes, and NADPH4 when subjected to thermal-stress conditions.In conclusion, the combination of SPIDES and TC has a positive effect on some pre and post-hatch traits of broiler chicks. Under heat stress challenge, thermal conditioning can modify the expression of antioxidant-related genes and Hsps, leading to the enhanced acquisition of thermotolerance as evidenced by lower expression of Hsps and NADPH4. While SPIDES does not have a significant role in thermotolerance acquisition.

Effect of short periods of incubation during egg storage (SPIDES) on hatchability of broiler breeder eggs

An experiment was conducted to evaluate the effect of Short Periods of Incubation During Egg Storage (SPIDES) on the hatchability of broiler breeder eggs. Broiler hatching eggs (500) were divided into five groups (A to E) containing 100 eggs in each and further subdivided into five replicates of 20 each. These groups were subjected to SPIDES treatment at temperature 37.50C and 55-60% relative humidity (RH) viz. control A (7 days egg storage without SPIDES and incubated on 8th day), B (10 days storage with 1 h SPIDES on 5th day and incubated on 11th day), C (10 days storage with 2 h SPIDES on 5th day and incubated on 11th day), D (15 days storage with 1 h SPIDES on 5th and 10th day and incubated on 16th day), E (15 days storage with 2 h SPIDES on 5th and 10th day and incubated on 16th day). All eggs were stored at 16-180C temperature and 65-70% RH. Egg weight loss, fertility, hatchability, embryonic mortality, hatch window, chick quality and healthy chick production were studied. SPIDES treatment in Group E restored hatchability and healthy chick production, reduced late embryonic mortality and improved day-old chick length. In conclusion, SPIDES treatment at 37.5°C and 55-60% RH for 2 h on 5th and 10th day during 15 days egg storage restored the hatchability; and improved embryonic survivability, healthy chick production and chick quality.

Human skin biofilm model: translational impact on swabbing and debridement

Objective: Wound biofilms are one of the greatest challenges in the therapy of hard-to-heal (chronic) wounds, as potent antimicrobial substances fail to eradicate bacteria within short incubation periods. Preclinical investigations using novel model systems that closely mimic the human wound environment and wound biofilm are required to identify new and effective therapeutic options. This study aims to identify bacterial colonisation patterns that are relevant for diagnosis and therapy. Method: In this study, a recently established human plasma biofilm model (hpBIOM) was incorporated into a wound within human dermal resectates after abdominoplasty. The interaction of the biofilm-forming bacteria meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa with the skin cells was investigated. Possible effects on wound healing processes in correlation with the persistence of the biofilm in the wound environment were analysed in patients with leg ulcers of different aetiologies and biofilm burden. Results: Using haematoxylin and eosin staining, species-dependent infiltration modes of the bacteria into the wound tissue were determined for the pathogens MRSA and Pseudomonas aeruginosa. The spreading behaviour correlated with clinical observations of the spatial distributions of the bacteria. In particular, the clinically prominent Pseudomonas aeruginosa-specific distension of the wound margin was identified as epidermolysis due to persistent infiltration. Conclusion: The hpBIOM applied in this study represents a potential tool for preclinical analyses dealing with approval processes for new antimicrobial applications. In terms of clinical practice, a microbiological swabbing technique including the wound margin should be routinely applied to prevent wound exacerbation.

Improving the consistency of experimental swine dysentery inoculation strategies

Swine dysentery (SD) caused by pathogenic Brachyspira spp. is an economic challenge for the swine industry. In research settings, experimental reproduction of swine dysentery typically relies on intragastric inoculation which has shown variable success. This project aimed to improve the consistency of the experimental inoculation protocol used for swine dysentery in our laboratory. Over six experiments, we evaluated the influence of group housing in inoculated pigs using a frozen-thawed broth culture of strongly hemolytic B. hyodysenteriae strain D19 (Trial A), compared the relative virulence of B. hyodysenteriae strains D19 and G44 (Trial B), compared inoculum volumes (50 mL vs 100 mL) for G44 and B. hampsonii 30446 (Trial C), and performed three independent trials evaluating intragastric inoculation using different oral inoculation methods: oral feed balls (Trial D), and oral syringe bolus of 100 mL (Trial E) or 300 mL (Trial F). Intragastric inoculation with a fresh broth culture of B. hyodysenteriae strain G44 resulted in a shorter incubation period and a higher proportionate duration of mucohemorrhagic diarrhea (MMHD) compared to D19. Intragastric inoculation with either 50 or 100 mL of B. hampsonii 30446 or B. hyodysenteriae (G44) were statistically equivalent. Oral inoculation with 100 mL or 300 mL also yielded similar results to intragastric inoculation but was more expensive due to the additional work and supplies associated with syringe training. Our future research will use intragastric inoculation with 100 mL of a fresh broth culture containing B. hyodysenteriae strain G44 as it yields a high incidence of mucohaemorrhagic diarrhea with a reasonable cost.

Viral emissions into the air and environment after SARS-CoV-2 human challenge: a phase 1, open label, first-in-human study

Effectively implementing strategies to curb SARS-CoV-2 transmission requires understanding who is contagious and when. Although viral load on upper respiratory swabs has commonly been used to infer contagiousness, measuring viral emissions might be more accurate to indicate the chance of onward transmission and identify likely routes. We aimed to correlate viral emissions, viral load in the upper respiratory tract, and symptoms, longitudinally, in participants who were experimentally infected with SARS-CoV-2. In this phase 1, open label, first-in-human SARS-CoV-2 experimental infection study at quarantine unit at the Royal Free London NHS Foundation Trust, London, UK, healthy adults aged 18-30 years who were unvaccinated for SARS-CoV-2, not previously known to have been infected with SARS-CoV-2, and seronegative at screening were recruited. Participants were inoculated with 10 50% tissue culture infectious dose of pre-alpha wild-type SARS-CoV-2 (Asp614Gly) by intranasal drops and remained in individual negative pressure rooms for a minimum of 14 days. Nose and throat swabs were collected daily. Emissions were collected daily from the air (using a Coriolis μ air sampler and directly into facemasks) and the surrounding environment (via surface and hand swabs). All samples were collected by researchers, and tested by using PCR, plaque assay, or lateral flow antigen test. Symptom scores were collected using self-reported symptom diaries three times daily. The study is registered with ClinicalTrials.gov, NCT04865237. Between March 6 and July 8, 2021, 36 participants (ten female and 26 male) were recruited and 18 (53%) of 34 participants became infected, resulting in protracted high viral loads in the nose and throat following a short incubation period, with mild-to-moderate symptoms. Two participants were excluded from the per-protocol analysis owing to seroconversion between screening and inoculation, identified post hoc. Viral RNA was detected in 63 (25%) of 252 Coriolis air samples from 16 participants, 109 (43%) of 252 mask samples from 17 participants, 67 (27%) of 252 hand swabs from 16 participants, and 371 (29%) of 1260 surface swabs from 18 participants. Viable SARS-CoV-2 was collected from breath captured in 16 masks and from 13 surfaces, including four small frequently touched surfaces and nine larger surfaces where airborne virus could deposit. Viral emissions correlated more strongly with viral load in nasal swabs than throat swabs. Two individuals emitted 86% of airborne virus, and the majority of airborne virus collected was released on 3 days. Individuals who reported the highest total symptom scores were not those who emitted most virus. Very few emissions occurred before the first reported symptom (7%) and hardly any before the first positive lateral flow antigen test (2%). After controlled experimental inoculation, the timing, extent, and routes of viral emissions was heterogeneous. We observed that a minority of participants were high airborne virus emitters, giving support to the notion of superspreading individuals or events. Our data implicates the nose as the most important source of emissions. Frequent self-testing coupled with isolation upon awareness of first symptoms could reduce onward transmissions. UK Vaccine Taskforce of the Department for Business, Energy and Industrial Strategy of Her Majesty's Government.

Cellular Internalization and Exiting Behavior of Zwitterionic 4-Armed Star-Shaped Polymers.

The zwitterionic phospholipid polymer poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) is amphiphilic copolymer, and it has been reported to directly penetrate cell membranes and have good cytocompatibility. Conventional PMBs are linear-type random copolymers that are polymerized by a free radical polymerization technique. In contrast, star-shaped polymers, or simple branched-type polymers, have unique properties compared to the linear types, for example, a viscosity based on the effect of the excluded volume. In this study, a branched architecture was introduced into a PMB molecular structure, and a 4-armed star-shaped PMB (4armPMB) was synthesized by an atom transfer radical polymerization (ATRP) technique known as living radical polymerization. Linear-type PMB was also synthesized using ATRP. The effects of the polymer architecture on cytotoxicity and cellular uptake were investigated. Both 4armPMB and LinearPMB were successfully synthesized, and these polymers were verified to be water soluble. Pyrene fluorescence in the polymer solution indicated that the architecture had no effect on the behavior of the polymer aggregates. In addition, these polymers caused no cytotoxicity or cell membrane damage. The 4armPMB and LinearPMB penetrated into the cells after a short incubation period, with similar rates. In contrast, the 4armPMB showed a quicker back-diffusion from the cells than that of LinearPMB. The 4armPMB showed fast cellular internalization and exiting behaviors.

Active sampling of volatile chemicals for non-invasive classification of chicken eggs by sex early in incubation.

According to industry estimates, approximately 7 billion day-old male chicks are disposed of annually worldwide because they are not of use to the layer industry. A practical process to identify the sex of the egg early in incubation without penetrating the egg would improve animal welfare, reduce food waste and mitigate environmental impact. We implemented a moderate vacuum pressure system through commercial egg-handling suction cups to collect volatile organic compounds (VOCs). Three separate experiments were set up to determine optimal conditions to collect eggs VOCs to discriminate male from female embryos. Optimal extraction time (2 min), storage conditions (short period of incubation during egg storage (SPIDES) at days 8-10 of incubation), and sampling temperature (37.5°C) were determined. Our VOC-based method could correctly differentiate male from female embryos with more than 80% accuracy. These specifications are compatible with the design of specialized automation equipment capable of high-throughput, in-ovo sexing based on chemical sensor microchips.

Photo gallery. Rare dermatoses. Part I

Orphan dermatoses are caused by both genetic causes and a number of autoimmune, inflammatory and infectious processes in the body. Congenital giant nevus is associated with serious complications: malignant melanoma, CNS lesions (neurocutaneous melanosis). Multiple epidermoid cysts are often a component of Gardner's syndrome. Angiolymphoid hyperplasia with eosinophilia, a vascular tumor formation with proliferation of histiocytoid endothelial cells, with severe lymphocytic and eosinophilic infiltration, recurs in 1/3 of cases. Morbigan's disease is persistent erythema and swelling of the middle third and upper part of the face. Skin mastocytosis in children is prone to spontaneous resolution during puberty. Squamous cell skin cancer accounts for 20% of all skin cancers and has a high risk of recurrence, metastasis, and death. Buschke's scleroderma is a scleroderma-like disease that causes progressive fibrous-mucinous thickening of the skin affecting the neck, shoulders, proximal upper extremities, and face. Fulminant (lightning) acne is a sharply exacerbated form of acne vulgaris, characterized by an acute onset and the appearance of confluent abscesses. Cases of acne fulminans have been observed during treatment with isotretinoin. Norwegian (crustose) scabies is associated with a compromised immune response, which allows the mites to multiply and can number in the millions. Pretibial myxedema (thyroid dermopathy) is a rare extrathyroid manifestation of Graves' disease along with thyrotoxicosis, thyroid hypertrophy, ophthalmopathy, and acropachy. Porokeratosis Mibelli predisposing factors of development are immunosuppressive conditions, malignancy is possible. Osteomas are formations from bone tissue in the dermis or subcutaneous fat as a result of metaplasia of fibroblasts into osteoblasts, or differentiation of primitive mesenchymal cells into osteoblasts and their migration to an ectopic site. Sarcoidosis of the skin is characterized by a variety of clinical forms, rarely observed before 40 years. Xanthomas with histiocytosis X ― a violation of lipid metabolism. The rural type of leishmaniasis (acute necrotizing) has a short incubation period, a significant spread of rashes and healing with the formation of scar tissue. The giant condyloma of BuschkeLevenshtein is characterized by progressive growth, large size and recurrent course, it can transform into squamous cell carcinoma. Degos disease ― malignant atrophic papulosis ― a rare disease caused by blockage of the arteries and veins.

Long-term prediction of the COVID-19 epidemics induced by Omicron-virus in China based on a novel non-autonomous delayed SIR model

Since the outbreak of COVID-19, the severe acute respiratory syndrome coronavirus 2 genome is still mutating. Omicron, a recently emerging virus with a shorter incubation period, faster transmission speed, and stronger immune escape ability, is soaring worldwide and becoming the mainstream virus in the COVID-19 pandemic. It is especially critical for the governments, healthcare systems, and economic sectors to have an accurate estimate of the trend of this disaster. By using different mathematical approaches, including the classical susceptible-infected-recovered (SIR) model and its extensions, many investigators have tried to predict the outbreaks of COVID-19. In this study, we employed a novel model which is based upon the well-known susceptible-infected-removed (SIR) model with the time-delay and time-varying coefficients in our previous works. We aim to predict the evolution of the epidemics effectively in nine cities and provinces of China, including A City, B City, C City, D City, E City, F City, G City, H City and I Province. The results show it is effective to model the spread of the large-scale and sporadic COVID-19 induced by Omicron virus by the novel non-autonomous delayed SIR compartment model. The significance of this study is that it can provide the management department of epidemic control with theoretical references and subsequent evaluation of the prevention, control measures, and effects.

Understanding the reaction balances behind the viability PCR protocols based on photoreactive dyes

Viability-PCR (vPCR) protocols are mainly based on photo-reactive dyes impermeant to intact cell membranes. The absence of cell barriers allows the reagent's interaction with the genetic material after a short incubation period. By light-induced reaction, DNA becomes the unsuitable mould for the polymerases and thus cannot be amplified and detected by PCR. General rules and consensus exist on critical aspects of successful vPCR protocol development. However, the understanding of the vPCR reaction concerning how much reagent is really effective or the proper amount of light has been poorly studied. The convenience of using 600 times more dye than bases pairs exist suggests that although these dyes are DNA intercalating reagents, many organic molecules can adsorb it. Concerning light, no exact references exist about how much energy is needed to activate the azide group of reagents such as propidium monoazide. Therefore, it cannot be calculated in terms of energy how much light needs a vPCR protocol. The general rule is to provide reagents and energy in excess.This work provides different responses (based on experimental results) to both questions, which can contribute to a better understanding of the theoretical basis of vPCR protocols.

Ascertaining the life history and thermal preferences and tolerances of the hot spring snailPhysella wrightiTe and Clarke (Gastropoda: Physidae)

Physella wrighti Te and Clarke, 1985 is an Endangered freshwater snail endemic to the Liard Hot Springs. The thermal characteristics of its environment suggest that water temperature (WT) is essential for the snail’s survival. Initially, Physella wrighti’s preferred WT was assessed, with 23 °C preferred. To determine if WT influenced the snail, the activity level, behaviour, survivability, number of egg masses (EMs) produced, number of eggs per mass (EPM), egg volume, EM viability, and incubation period (IP) were examined in 13 °C, 23 °C (preferred WT), and 33 °C water. No differences were found in activity level, but snails in 33 °C left the water more frequently, experienced total mortality, had the shortest survival length, produced the fewest EMs, however, had the shortest IP. Snails in 13 °C survived the longest, produced the most EPM, but had the lowest viability. Snails in 23 °C produced the most EMs and had the greatest viability, EPM did not differ from 33 °C, and IP was between 13 °C and 33 °C. These data indicate that Physella wrighti benefits more from WTs in the lower range of its habitat and has implications for its ecology and conservation.

Reduced levels of NGF shift astrocytes toward a neurotoxic phenotype.

Nerve growth factor (NGF) is critical for neuronal physiology during development and adulthood. Despite the well-recognized effect of NGF on neurons, less is known about whether NGF can actually affect other cell types in the central nervous system (CNS). In this work, we show that astrocytes are susceptible to changes in ambient levels of NGF. First, we observe that interfering with NGF signaling in vivo via the constitutive expression of an antiNGF antibody induces astrocytic atrophy. A similar asthenic phenotype is encountered in an uncleavable proNGF transgenic mouse model (TgproNGF#72), effectively increasing the brain proNGF levels. To examine whether this effect on astrocytes is cell-autonomous, we cultured wild-type primary astrocytes in the presence of antiNGF antibodies, uncovering that a short incubation period is sufficient to potently and rapidly trigger calcium oscillations. Acute induction of calcium oscillations by antiNGF antibodies is followed by progressive morphological changes similar to those observed in antiNGF AD11 mice. Conversely, incubation with mature NGF has no effect on either calcium activity nor on astrocytic morphology. At longer timescales, transcriptomic analysis revealed that NGF-deprived astrocytes acquire a proinflammatory profile. In particular, antiNGF-treated astrocytes show upregulation of neurotoxic transcripts and downregulation of neuroprotective mRNAs. Consistent with that data, culturing wild-type neurons in the presence of NGF-deprived astrocytes leads to neuronal cell death. Finally, we report that in both awake and anesthetized mice, astrocytes in layer I of the motor cortex respond with an increase in calcium activity to acute NGF inhibition using either NGF-neutralizing antibodies or a TrkA-Fc NGF scavenger. Moreover, in vivo calcium imaging in the cortex of the 5xFAD neurodegeneration mouse model shows an increased level of spontaneous calcium activity in astrocytes, which is significantly reduced after acute administration of NGF. In conclusion, we unveil a novel neurotoxic mechanism driven by astrocytes, triggered by their sensing and reacting to changes in the levels of ambient NGF.

SARS-CoV-2 incubation period across variants of concern, individual factors, and circumstances of infection in France: a case series analysis from the ComCor study

The incubation period of SARS-CoV-2 has been estimated for the known variants of concern. However, differences in study designs and settings make comparing variants difficult. We aimed to estimate the incubation period for each variant of concern compared with the historical strain within a unique and large study to identify individual factors and circumstances associated with its duration. In this case series analysis, we included participants (aged ≥18 years) of the ComCor case-control study in France who had a SARS-CoV-2 diagnosis between Oct 27, 2020, and Feb 4, 2022. Eligible participants were those who had the historical strain or a variant of concern during a single encounter with a known index case who was symptomatic and for whom the incubation period could be established, those who reported doing a reverse-transcription-PCR (RT-PCR) test, and those who were symptomatic by study completion. Sociodemographic and clinical characteristics, exposure information, circumstances of infection, and COVID-19 vaccination details were obtained via an online questionnaire, and variants were established through variant typing after RT-PCR testing or by matching the time that a positive test was reported with the predominance of a specific variant. We used multivariable linear regression to identify factors associated with the duration of the incubation period (defined as the number of days from contact with the index case to symptom onset). 20 413 participants were eligible for inclusion in this study. Mean incubation period varied across variants: 4·96 days (95% CI 4·90-5·02) for alpha (B.1.1.7), 5·18 days (4·93-5·43) for beta (B.1.351) and gamma (P.1), 4·43 days (4·36-4·49) for delta (B.1.617.2), and 3·61 days (3·55-3·68) for omicron (B.1.1.529) compared with 4·61 days (4·56-4·66) for the historical strain. Participants with omicron had a shorter incubation period than participants with the historical strain (-0·9 days, 95% CI -1·0 to -0·7). The incubation period increased with age (participants aged ≥70 years had an incubation period 0·4 days [0·2 to 0·6] longer than participants aged 18-29 years), in female participants (by 0·1 days, 0·0 to 0·2), and in those who wore a mask during contact with the index case (by 0·2 days, 0·1 to 0·4), and was reduced in those for whom the index case was symptomatic (-0·1 days, -0·2 to -0·1). These data were robust to sensitivity analyses correcting for an over-reporting of incubation periods of 7 days. SARS-CoV-2 incubation period is notably reduced in omicron cases compared with all other variants of concern, in young people, after transmission from a symptomatic index case, after transmission to a maskless secondary case, and (to a lesser extent) in men. These findings can inform future COVID-19 contact-tracing strategies and modelling. Institut Pasteur, the French National Agency for AIDS Research-Emerging Infectious Diseases, Fondation de France, the INCEPTION project, and the Integrative Biology of Emerging Infectious Diseases project.

Development of a New Analytical Method for Estimation of Trifluoperazine-HCl in Pharmaceutical Formulation

Background: Coronavirus disease 2019 (COVID-19) has spread worldwide and poses a serious public health-threat. High IL-6 levels were associated with the severity of COVID-19 and del to the use of anti-IL-6 Tocilizumab during the pandemic. Therefore, this case-control study was conducted to evaluate the role of Tocilizumab on the mortality rate among severe and critically ill COVID-19 patients. Method: A case-control study relied on the use of an electronic data collection sheet; the data were collected from February to May 2022. The study was performed on adult patients with critical COVID-19 at three major hospitals in the Gaza Strip, Palestine where patients were treated in the intensive care units (ICUs). Patients from the hospitals were included and divided into two groups by simple random sampling technique. Results: Of the 202 patients with critical COVID-19 admitted to ICUs of three hospitals, 102 (50.5%) were treated with Tocilizumab. A total of 58 (56.9%) patients in the Tocilizumab group were cured, and 44 (43.1%) died. In the control group, only 26 (26.0%) were cured and 72.0% died. There was no statistically significant effect of Tocilizumab on total hospital stay and ventilation periods. Patients treated with Tocilizumab had a longer stay in the ICU (14.02 ±8.796 days compared to 10.52 ± 9.596 days in the control group, P = 0.027), but shorter incubation periods were observed in the same group (3.25 ±1.137 days in Tocilizumab group compared to 7.38 ±3.376 days in the control group P = 0.036). Conclusion: This study found that administration of Tocilizumab can improve clinical outcomes, reduce risk of mortality, and frequency of intubation in patients severely infected with COVID-19. However, there was no significant difference between the two groups in terms of hospitalization times and mechanical ventilation needs. Based on the current report, healthcare specialists should consider Tocilizumab with the updated treatment guidelines for critically ill COVID-19 patients.

The effect of storage periods and SPIDES on embryonic mortality, hatching characteristics, and quality of newly hatched chicks in broiler eggs

sEgg storage duration can affect embryo mortality, hatching characteristics, hatching time, and post-hatch chick quality. In order to assess these effects, the impact of storage duration (5 days, 10 days, 15 days) and short incubation period during egg storage (SPIDES) investigated further 18, 900 eggs of broiler breeder (ROSS 308) in 3 × 2 factorial arrangement design. In the SPIDES treatment, the egg shell temperature was raised from its storage temperature (18 °C) and held at 100 °F for 3.5 h. Storage periods could significantly (P < 0.05) influence on embryo mortality (total, early, middle, and late), hatchability of both the total eggs and fertile eggs. The SPIDES treatment had a significant (P < 0.05) impact on a lower embryonic death rate and improved egg hatchability. Eggs stored for 5 days and eggs treated with SPIDES significantly (P < 0.001) shorten hatching time, batch’s 90% hatching time (T 90% H), mean hatching time (MHT), maximal hatching period (MHP), and hatching window (HW). Chick quality was also determined, whereas storing eggs for 5 days and using the SPIDES treatment resulted in enhanced (P < 0.001) chick weight relative to egg weight (CW/EW), activity (AC), and chick quality score (CQS). The residual yolk sac weight (RYSW), unhealed navel (UHN %), and dirty feather (DF%) recorded the lowest (P < 0.001) values compared to long storage periods and control group. Finally, stored for 5 days treated by SPIDES positively affected the hatchability characteristics, the shortening hatching time, and the quality of chicks. Regarding the results, it was confirmed that using the SPIDES treatment to prevent the harmful effects of broiler eggs being stored for an extended period of time is a viable option.

Chitosan Grafted with Thermoresponsive Poly(di(ethylene glycol) Methyl Ether Methacrylate) for Cell Culture Applications

Chitosan is a polysaccharide extracted from animal sources such as crab and shrimp shells. In this work, chitosan films were modified by grafting them with a thermoresponsive polymer, poly(di(ethylene glycol) methyl ether methacrylate) (PMEO2MA). The films were modified to introduce functional groups useful as reversible addition-fragmentation chain transfer (RAFT) agents. PMEO2MA chains were then grown from the films via RAFT polymerization, making the chitosan films thermoresponsive. The degree of substitution of the chitosan-based RAFT agent and the amount of monomer added in the grafting reaction were varied to control the length of the grafted PMEO2MA chain segments. The chains were cleaved from the film substrates for characterization using 1H NMR and a gel permeation chromatography analysis. Temperature-dependent contact angle measurements were used to demonstrate that the hydrophilic-hydrophobic nature of the film surface varied with temperature. Due to the enhanced hydrophobic character of PMEO2MA above its lower critical solution temperature (LCST), the ability of PMEO2MA-grafted chitosan films to serve as a substrate for cell growth at 37 °C (incubation temperature) was tested. Interactions with cells (fibroblasts, macrophages, and corneal epithelial cells) were assessed. The modified chitosan films supported cell viability and proliferation. As the temperature is lowered to 4 °C (refrigeration temperature, below the LCST), the grafted chitosan films become less hydrophobic, and cell adhesion should decrease, facilitating their removal from the surface. Our results indicated that the cells were detached from the films following a short incubation period at 4 °C, were viable, and retained their ability to proliferate.

BF.7 Omicron subvariant in India and China: a raising concern - correspondence.

BF.7 Omicron subvariant in India and China: a raising concern - correspondence.

Dynamics of disease characteristics and viral RNA decay in patients with asymptomatic and mild infections during the Omicron wave in Shanghai, China: A retrospective cohort study

ObjectivesAsymptomatic infections and mild diseases were more common during the Omicron outbreak in Shanghai, China in 2022. This study aimed to assess the characteristics and viral RNA decay between patients with asymptomatic and mild infections. MethodsA total of 55,111 patients infected with SARS-CoV-2 who were quarantined in the National Exhibition & Convention Center (Shanghai) Fangcang shelter hospital within 3 days after diagnosis from April 9 to May 23, 2022 were enrolled. The kinetics of cycle threshold (Ct) values of reverse transcription-polymerase chain reaction were assessed. The influencing factors for disease progression and the risk factors for the viral RNA shedding time (VST) were investigated. ResultsOn admission, 79.6% (43,852/55,111) of the cases were diagnosed with asymptomatic infections, and 20.4% were mild diseases. However, 78.0% of initially asymptomatic subjects developed mild diseases at the follow-up. The final proportion of asymptomatic infections was 17.5%. The median time of symptom onset, the duration of symptoms, and the VST were 2 days, 5 days, and 7 days, respectively. Female, age 19-40 years, underlying comorbidities with hypertension and diabetes, and vaccination were associated with higher risks of progressing to mildly symptomatic infections. In addition, mildly symptomatic infections were found to be associated with prolonged VST compared with asymptomatic infections. However, the kinetics of viral RNA decay and dynamics of Ct values were similar among asymptomatic subjects, patients with asymptomatic-to-mild infection, and patients with mild infection. ConclusionA large proportion of initially diagnosed asymptomatic Omicron infections is in the presymptomatic stage. The Omicron infection has a much shorter incubation period and VST than previous variants. The infectivity of asymptomatic infections and mildly symptomatic infections with Omicron is similar.

Dark-induced chloroplast relocation depends on actin filaments in the liverwort Apopellia endiviifolia along with the light- and cold-induced relocations.

Chloroplasts move to the periclinal walls of cells under weak light to harness light energy for photosynthesis and to anticlinal walls to avoid strong light. These responses involve the cytoskeleton components microtubules and/or actin filaments. In the dark, chloroplasts move to the anticlinal cell walls bordering neighbouring cells (dark-positioning response), but this response in various plants normally requires a prolonged dark incubation period, which has hampered analysis. However, we recently demonstrated the dark-positioning response that can be induced after a short period of dark incubation in the liverwort Apopellia endiviifolia. Here, we investigated whether the cytoskeleton components function in the dark-positioning response of A. endiviifolia cells. Microtubules and actin filaments were fluorescentlyvisualised in A. endiviifolia cells and were disrupted following treatment with the microtubule and actin filament polymerisation inhibitors. The dark-positioning response was unaffected in the cells with disrupted microtubules. By contrast, the dark-positioning response was inhibited by the disruption of actin filaments. The disruption of actin filaments also restricted chloroplast mobility during light- and cold-dependent chloroplast movements in A. endiviifolia. Therefore, the dark-positioning response of A. endiviifolia depends solely on an actin filament-associated motility mechanism, as do the light- and cold-dependent chloroplast responses.

Ground nesting in passerine birds: evolution, biogeography and life history correlates

Nest location is one of the key components of avian reproduction and sharp transitions between different nest location strategies may have profound ecological and evolutionary consequences. Here, we used a phylogenetically‐informed comparative framework to reconstruct the evolution of ground nesting behaviour in passerine birds, quantify its biogeographical and habitat variation, and test for its associations with life history traits. Our dataset comprised over 1600 species distributed worldwide and representing ca 90% of all extant passerine families. Our analyses revealed a scattered phylogenetic distribution and moderate phylogenetic signal in the occurrence of ground nesting in passerines. We also found relatively high forward and backward transitions rates between character states of ground and non‐ground nesting, indicating strong evolutionary lability. Non‐ground nesting was identified as a likely ancestral state at the root of passerine phylogeny. Occurrence of ground nesting was clearly associated with habitat variation, as open habitats generally supported greater proportion of ground nesting species than non‐open habitats (forests). Within the major habitat categories we found greater proportion of ground nesters in boreal and temperate than subtropical and tropical zones. This reflected a general latitudinal gradient in the occurrence of ground nesting, with higher proportion of ground nesting species at higher latitudes (especially at the northern hemisphere). Ground nesting was also associated with fast life histories, as ground nesters had larger clutches, shorter incubation periods and faster chick development rates than non‐ground nesters. This variation was possibly driven by higher predation rates on nestlings and adult birds in ground nesting species. Our study lays a foundation for a comprehensive understanding of mechanisms and processes that have driven macroevolution of ground nesting behaviour in the most species‐rich extant avian lineage.