Enhancing microbial diversity as well as multi-organ health in hind-limb unloaded mice

During space travel, the gut microbiota is changed which can lead to health-related issues. Previously, we utilized the hind-limb unloaded (HU) mouse, which is an established ground-based in-vivo model of microgravity and observed altered gut microbiota. In this study, we evaluated the beneficial effects of novel bacterial conditioned media in HU mice to understand if they can offset the effects of unloading in the HU mouse model. We aimed to explore the influence of bacterial conditioned media on diversity and quantity of intestinal microbes in HU mice, and investigated the microarchitecture of mice retinas and kidneys to evaluate the potential systemic effects of bacterial conditioned media in HU mice. Four-month-old, male C57/Bl6 mice were separated into groups: including the ground-based control group, the HU group mice fed with vehicle as placebo (HU-placebo mice), and the HU group fed with bacterial conditioned media (HU-CP mice) and kept under controlled environmental conditions for three weeks. Next, mice were sacrificed; gut dissections were conducted, and metagenomic analysis of bacterial species was performed via DNA extraction and 16S rRNA analysis. The results revealed an HU-induced reduction in intestinal microbial diversity, and an increase in pathogenic bacteria dominated by Firmicutes (45%). In contrast, supplementation with bacterial conditioned media for three weeks led to a significant increase in gut microbial diversity with noticeable changes in the OTUs abundance in the HU mice. Additionally, HU-induced muscle weakness and structural abnormalities in the retina and kidney were partially prevented with bacterial conditioned media. Moreover, a greater diversity of several bacteria in the HU-CP was observed including, Bacteriodota, Firmicutes, Proteobacteria, Actionobacteriota, Verrucomicorbiota, Cyanobacteria, Gemmatimonadota, Acidobacteriota, Chloroflexi, Myxococcota, and others. Prospective research involving molecular mechanistic studies are needed to comprehend the systemic effects of bacterial metabolites conditioned media on experimental animal models under chronic stress.

P-390 Serum homocysteine and uterine artery Doppler ultrasound in combination has better predictive accuracy in women with preeclampsia: useful tool for early screening in everyday practice

Study question

Is serum homocysteine combined with uterine-artery Doppler were effective in predicting preeclampsia (≥140mmHg/≥90mmHg blood pressure) in singleton pregnancy during 11–15 weeks of gestation?

Summary answer

Combination of serum homocysteine levels with uterine-artery Doppler is superior to individual presence of biochemical/ultrasound marker/s making the duo effective for early screening in preeclampsia.

What is known already

American College of Obstetricians and Gynecologists and National Institute for Care and Health Excellence recommend identifying patients who are at high risk of developing preeclampsia based on medical history. Recently, biochemical and ultrasound markers were investigated for prediction of preeclampsia, but none of them were predictably reliable, valid, and suitable for routine clinical use. Increased levels of homocysteine in 1st-trimester, seems to signal onset of preeclampsia later in pregnancy portraying severity of the disease as well. We aimed to identify predictive value of serum homocysteine combined with uterine-artery Doppler in singleton pregnancy during 11–15 weeks of gestation for preeclampsia.

Study design, size, duration

One hundred forty-two consented singleton pregnant women (28-45 years) at gestational age of 11–15 weeks, recruited between January to December 2021 from Institute of Reproductive Medicine, Kolkata were enrolled in the study. Women who used aspirin as a prophylaxis for preeclampsia or were diagnosed to have fetal, structural or chromosomal abnormalities were excluded from the study (n = 7). Maternal age, weight and height, mean arterial pressure, parity, and obstetric history were documented.

Participants/materials, setting, methods

Uterine-artery Doppler ultrasound and serum homocysteine levels were performed transabdominally and using ELISA respectively. Pregnancy outcomes were recorded. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) at optimal cut-off values were determined to predict preeclampsia. Optimal cut-off values for homocysteine levels were calculated using receiver operator characteristic curve (ROC). Chi-square test, Fisher’s exact test, unpaired t test, and Mann–Whitney U test were used when appropriate. P-value <0.05 was considered statistically significant.

Main results and the role of chance

16 cases had preeclampsia (11.26%) of whom 9 had early-onset preeclampsia (6.33%). Baseline characteristics including maternal-age (>35 or<), parity, body-mass- index, and gestational-age at measurement were not significantly different between two groups excepting higher (p < 0.001) mean arterial blood pressure (mmHg) at first trimester (97.2±6.4 vs. 81.1±7.2) in preeclampsia. Preeclamptic women had significantly higher (p < 0.001) serum homocysteine levels (μmol/l) (26.1±3.5 vs 10.2± 5.6) than normotensive pregnant women (n = 119). No difference in mean pulsatility (PI) of uterine-artery was observed (1.78±0.64 vs. 1.72±0.48) excluding significantly high (p > 0.02) in women with early-onset preeclampsia than control (2.11±0.81 vs. 1.39±0.92). However, lower (p < 0.01) gestational age (weeks) (35.4±2.1 vs. 37.6±1.4), and neonatal birth weight (gms) (2937.3±578.2 vs. 3227.6±421.5) with higher (p < 0.001) preterm delivery (25% vs 5.04%), low birth weight (25% vs 5.04%) and neonatal respiratory distress syndrome (12.5% vs. 0.84%) was documented in preeclampsia than control/s. The optimal cut-off value of serum homocysteine with PI levels, from ROC (AUC=0.735, p < 0.001) was superior to individual ROC (AUC=0.451; AUC=0.268). The sensitivity, specificity, PPV, and NPV were 67.7%, 70.5%, 1.7%, and 98.5%, respectively using a combination of abnormal serum homocysteine levels with abnormal uterine artery Doppler PI (above 95th percentile) and used as a predictive value for preeclampsia.

Limitations, reasons for caution

The limitation of this study was that there were small cases of early-onset preeclampsia. Additional studies with a larger sample size of early-onset preeclampsia and other models using serum homocysteine, combined with uterine artery Doppler, and maternal characteristic risk factors should be conducted.

Wider implications of the findings

Early screening of preeclampsia by using combination of serum homocysteine and uterine artery Doppler during first trimester (11–15 weeks) at the same visit may be more effective and allows the timing for using early low-dose aspirin prophylaxis in order to prevent preeclampsia.

Trial registration number

Not applicable

Viral Metagenomics Revealed a Novel Cardiovirus in Feces of Wild Rats

BACKGROUND/AIMS

Cardiovirus is a genus of viruses belonging to the family Picornaviridae. Here, we used viral metagenomic techniques to detect the viral nucleic acid in the fecal samples from wild rats in Zhenjiang city in China.

METHOD

Fecal samples were collected from 20 wild rats and pooled into four sample pools and then subjected to libraries construction which were then sequenced on Illumina MiSeq platform. The sequenced reads were analyzed using viral metagenomic analysis pipeline.

RESULTS

A novel cardiovirus from feces of a wild rat was identified, named amzj-2018, of which the complete genome was acquired. Phylogenetic analysis based on the complete amino acid sequence of polyprotein revealed that amzj-2018 formed a separate branch located between clusters of Saffold virus and Rat Theilovirus 1 (RTV-1). Phylogenetic analysis based on different regions of the polyproteins, including P1, P2, P3, and P2+P3, respectively, showed discordant trees, where the tree based on P3 region indicated that amzj-2018 clustered separately between Theiler's murine encephalomyelitis virus and RTV-1.

CONCLUSION

The complete genome of a cardiovirus was determined from the feces of wild rats which belonged to a novel type of cardiovirus based on phylogenetic analysis. Whether it is associated with disease needs further investigation.

Determination of heavy metal contents in water, sediments, and fish tissues of Shizothorax plagiostomus in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan

The present study was conducted to investigate the contamination of water, sediments, and fish tissues with heavy metals in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan. Water, sediments, and fish (Shizothorax plagiostomus) samples were collected from September 2012 to January 2013 at three different sites (upstream site at Sharigut, sewage site at Timergara, and downstream site at Sadoo) of river Panjkora. The concentrations of heavy metals in water were in the order Zn > Cu ≈ Pb > Ni ≈ Cd with mean values of 0.30, 0.01, 0.01, 0.0 and 0.0 mg/l, respectively, which were below the maximum permissible limits of WHO for drinking water. In sediments, heavy metals were found in the order Cu > Zn > Ni > Pb > Cd with mean concentrations of 50.6, 38.7, 9.3, 8, and 0.4 mg/kg, respectively. Ni and Cd were not found in any fish tissues, but Zn, Cu, and Pb were detected with the mean concentration ranges of 0.04-1.19, 0.03-0.12, and 0.01-0.09 μg/g, respectively. The present study demonstrates that disposal of waste effluents causes a slight increase in the concentration of heavy metals in river Panjkora as revealed by variation in metal concentrations from upstream to downstream site. Sewage disposal was also found to change physicochemical characteristics of Panjkora water. At present, water and fish of river Panjkora are safe for human consumption, but the continuous sewage disposal may create problems in the future.

Role of RAS2 in recovery from chronic stress: effect on yeast life span

The replicative life span of Saccharomyces cerevisiae was previously shown to be modulated by the homologous signal transducers Ras1p and Ras2p in a reciprocal manner. We have used thermal stress as a life span modulator in order to uncover functional differences between the RAS genes that may contribute to their divergent effects on life span. Chronic exposure of cells throughout life to recurring heat shocks at sublethal temperatures decreased their replicative life span. ras2 mutants, however, suffered the largest decrease compared to wild-type and ras1 mutant cells. The decrease was correlated with a substantial delay in resumption of budding upon recovery from these heat shocks, indicating an impaired renewal of cell cycling. Detailed analysis of gene expression showed that, during recovery, ras2 mutants were selectively impaired in down-regulation of stress-responsive genes and up-regulation of growth-promoting genes. Our results suggest that one of the functions of RAS2 in maintaining life span, for which RAS1 does not substitute, is to ensure renewal of growth and cell division after bouts of stress that cells encounter during their life. This activity of RAS2 is effected by the cyclic AMP pathway. Overexpression of RAS2, but not RAS2(ser42) which is deficient in the activation of adenylate cyclase, completely reversed the effect of chronic stress on life span. Thus, RAS2 is limiting for longevity in the face of chronic stress. Since RAS2 is known to down-regulate stress responses, this demonstrates that for longevity the ability to recover from stress is at least as important as the ability to mount a stress response.

Heat stress-induced life span extension in yeast

The yeast Saccharomyces cerevisiae has a limited life span that can be measured by the number of times individual cells divide. Several genetic manipulations have been shown to prolong the yeast life span. However, environmental effects that extend longevity have been largely ignored. We have found that mild, nonlethal heat stress extended yeast life span when it was administered transiently early in life. The increased longevity was due to a reduction in the mortality rate that persisted over many cell divisions (generations) but was not permanent. The genes RAS1 and RAS2 were necessary to observe this effect of heat stress. The RAS2 gene is consistently required for maintenance of life span when heat stress is chronic or in its extension when heat stress is transient or absent altogether. RAS1, on the other hand, appears to have a role in signaling life extension induced by transient, mild heat stress, which is distinct from its life-span-curtailing effect in the absence of stress and its lack of involvement in the response to chronic heat stress. This distinction between the RAS genes may be partially related to their different effects on growth-promoting genes and stress-responsive genes. The ras2 mutation clearly hindered resumption of growth and recovery from stress, while the ras1 mutation did not. The HSP104 gene, which is largely responsible for induced thermotolerance in yeast, was necessary for life extension induced by transient heat stress. An interaction between mitochondrial petite mutations and heat stress was found, suggesting that mitochondria may be necessary for life extension by transient heat stress. The results raise the possibility that the RAS genes and mitochondria may play a role in the epigenetic inheritance of reduced mortality rate afforded by transient, mild heat stress.

The translational cis-regulatory element of mammalian ribosomal protein mRNAs is recognized by the plant translational apparatus

The translational efficiency of mammalian ribosomal protein mRNAs correlates with the growth status of the cells and its control is mediated through a 5' terminal oligopyrimidine tract (5' TOP) common to all these mRNAs. In the present study, we demonstrate that the plant translational apparatus, as represented by wheat-germ extract, discriminates against mammalian mRNAs containing this motif to the same extent as do quiescent mammalian cells. Moreover, mutations in the 5' TOP, which abolish the growth-dependent translational control of the respective mRNAs in mammalian cells, render these mRNAs refractory to discrimination in the plant cell-free system. This selective discrimination reflects neither the specific instability of 5' TOP-containing mRNAs during the incubation in vitro nor a lower competitive potential for the cap-binding protein. The lower in vitro translational efficiency of these mRNAs is an inherent feature which is independent of whether they were derived from polysomes or messenger ribonucleoprotein particles of the transfected mammalian cells. The conservation of the discriminatory property of the translational apparatus between the animal and plant kingdoms is discussed from mechanistic and evolutionary points of view.

Overexpression of initiation factor eIF-4E does not relieve the translational repression of ribosomal protein mRNAs in quiescent cells

Translation of ribosomal protein (rp) mRNA is selectively repressed in mouse erythroleukemia (MEL) cells, which cease to proliferate upon differentiation, and in NIH 3T3 cells, for which growth is arrested by either serum starvation, contact inhibition, or treatment with the DNA polymerase inhibitor, aphidicolin. The efficiency of translation of rp mRNAs correlates with the expression of the gene encoding the cap binding protein, eIF-4E, as indicated by the fact that the abundance of the corresponding mRNA and protein also fluctuates in a growth-dependent manner. To examine the hypothesis that eIF-4E plays a role in regulation of the translation efficiency of rp mRNAs, we utilized an NIH 3T3-derived eIF-4E-overexpressing cell line. These cells overproduce eIF-4E to the extent that even under conditions of growth arrest, the abundance of the respective protein in its active (phosphorylated) form is higher than that found in exponentially growing NIH 3T3 cells. Nevertheless, this surplus amount of eIF-4E does not prevent the translational repression of rp mRNAs when the growth of these cells is arrested by blocking DNA synthesis with aphidicolin or hydroxyurea. In complementary experiments we used an in vitro translation system to compare the competitive potential of mRNAs, containing the translational cis-regulatory element (5' terminal oligopyrimidne tract) and mRNAs lacking such a motif, for the cap binding protein. Our results demonstrate that both types of mRNAs, regardless of their translational response to growth arrest, exhibit similar sensitivity to the cap analogue m7G(5')ppp(5')G. It appears, therefore, that the presence of the regulatory sequence at the 5' terminus of rp mRNAs does not lessen its competitive potential for the cap binding protein and that the growth-dependent decrease in the activity of eIF-4E does not play a key role in the repression of translation of rp mRNAs.

Vertebrate mRNAs with a 5'-terminal pyrimidine tract are candidates for translational repression in quiescent cells: characterization of the translational cis-regulatory element

The translation of mammalian ribosomal protein (rp) mRNAs is selectively repressed in nongrowing cells. This response is mediated through a regulatory element residing in the 5' untranslated region of these mRNAs and includes a 5' terminal oligopyrimidine tract (5' TOP). To further characterize the translational cis-regulatory element, we monitored the translational behavior of various endogenous and heterologous mRNAs or hybrid transcripts derived from transfected chimeric genes. The translational efficiency of these mRNAs was assessed in cells that either were growing normally or were growth arrested under various physiological conditions. Our experiments have yielded the following results: (i) the translation of mammalian rp mRNAs is properly regulated in amphibian cells, and likewise, amphibian rp mRNA is regulated in mammalian cells, indicating that all of the elements required for translation control of rp mRNAs are conserved among vertebrate classes; (ii) selective translational control is not confined to rp mRNAs, as mRNAs encoding the naturally occurring ubiquitin-rp fusion protein and elongation factor 1 alpha, which contain a 5' TOP, also conform this mode of regulation; (iii) rat rpP2 mRNA contains only five pyrimidines in its 5' TOP, yet this mRNA is translationally controlled in the same fashion as other rp mRNAs with a 5' TOP of eight or more pyrimidines; (iv) full manifestation of this mode of regulation seems to require both the 5' TOP and sequences immediately downstream; and (v) an intact translational regulatory element from rpL32 mRNA fails to exert its regulatory properties even when preceded by a single A residue.

Atypical erysipelas caused by group G streptococci in a patient with cured Hodgkin's disease

Erysipelas developed in a young woman whose condition had been in remission for ten years after treatment of stage IIIA Hodgkin's disease. The erysipelas was atypical both in its clinical manifestation and its causative organism. The patient had an erythematous, macular eruption on both buttocks and thighs. Group G streptococci, a rare cause of erysipelas, were isolated from both blood cultures and a skin biopsy specimen. The unusual clinical manifestation of the disease when the patient was initially seen may have been the result of a group G streptococcal bacteremia, coupled with impairment of the lymphatic drainage of the involved area from a partial thoracic duct obstruction and a restrictive cardiomyopathy, both secondary to previous irradiation treatment.