Heat-stable spores of carotenoid-producing Bacillus marisflavi and non-pigmented Bacillus subtilis cooperatively promote growth, quality, and gut microbiota of white-leg shrimp

We evaluated the benefits of heat-stable carotenoid-producing Bacillus marisflavi SH8 spores individually and in combination with non-pigmented Bacillus subtilis SH23 spores on growth, colour change, nutritional content, innate immunity, and gut microbiota of white-leg shrimp. White-leg shrimp (Litopenaeus vannamei; n = 30 per tank; 2 tanks per group) were provided feed without (control group) or with SH8, SH23, or mixed spores (total, 1 × 106 cfu/g pellet) for 28 d. The SH8 and SH8-23 combination groups had significantly higher specific growth rates (9.6 and 11.0%), improved red-colour score (4 scores), astaxanthin concentration (1.8- and 2.3-fold), lipid contents (30 and 50%), and superoxidase dismutase activity (8.5 and 12.3%) than that of the control group. Analysis of shrimp's gut microbiome using 16S rRNA metagenome sequencing revealed increased abundance of four useful species and reduced abundance of four harmful species in the combination group than in the control group. Heat-stable Bacillus spore combination improved growth parameters, nutrient content, red-colour score, live counts, and abundance of useful bacteria in the gut of L. vannamei. This is the first study to show the benefits of combining highly heat-stable pigmented and non-pigmented Bacillus spores and their possible mechanisms in a shrimp model.

Testing a global standard for quantifying species recovery and assessing conservation impact

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species' viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species' recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard.

Association of body mass index with non-achievement of target low-density lipoprotein level in older patients at very high cardiovascular risk: a multicentre study

Introduction

Low-density lipoprotein cholesterol (LDL-c) is a well-established risk factor for atherosclerotic cardiovascular disease. Nonetheless, the association of body mass index (BMI) with non-achievement of target LDL-c level in older patients with type 2 diabetes (T2D) at very high cardiovascular risk is unknown.

Purpose

To investigate whether BMI is associated with non-achievement of target LDL-c level in older patients with T2D at very high cardiovascular risk.

Methods

From December 2019 to June 2020, in this multicentre prospective cross-sectional study, we enrolled 733 consecutive outpatients aged ≥60 years with T2D at very high cardiovascular risk in whom LDL-c levels could be measured after any stable lipid-lowering therapy for ≥6 months. Achievement of target lipid level was assessed based on the 2019 guidelines of the European Society of Cardiology for dyslipidaemia. Factors associated with non-achievement of target LDL-c level were determined using logistic regression analysis.

Results

Of the total cases (age, 68.6±7.2 years; men, 51.3%), 654 patients (89.2%) did not achieve an aggressive target LDL-c level of <1.4 mmol/L. Target non-high-density lipoprotein cholesterol level of <2.2 mmol/L and triglyceride level of <1.7 mmol/L were not achieved in 87.9% and 56.2% of the patients, respectively. In the multivariate model, BMI was the only factor associated with failure to achieve target LDL-c level, but not other factors such as age, sex, education level, smoking, and comorbidities. The adjusted odds ratio were 0.88 (95% confidence interval [95% CI], 0.24–3.21; P=0.84) for underweight, 1.57 (95% CI, 0.87–2.81; P=0.13) for overweight, and 2.63 (95% CI, 1.43–4.83; P=0.002) for obesity (normal weight was set as reference) status.

Conclusions

Non-achievement of target LDL-c level is highly prevalent in older patients with T2D at very high cardiovascular risk. Obesity, defined by BMI, can be a factor associated with non-achievement of the target. The findings highlight the importance of management of lipid levels in older patients with T2D.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Screening of pigmented Bacillus aquimaris SH6 from the intestinal tracts of shrimp to develop a novel feed supplement for shrimp

AIMS

To develop a novel feed supplement for shrimp using pigmented spore-forming bacterial strains isolated from their gastrointestinal tracts.

METHODS AND RESULTS

Eight pigmented Bacillus strains were selected from the isolates based on high production of heat-stable spores, typical UV-Vis spectra of produced carotenoids (400-550 nm), and free radical scavenging activity of their extracts. Of the eight strains, the red-orange pigmented Bacillus aquimaris SH6 was selected because it showed the highest abundance in shrimp guts (70% population). Whiteleg shrimp (n = 30 per group) fed with SH6 spores, at >3 × 10⁶  CFU g^-1  pellet for 4 weeks had redder colour (score of 21-23 vs 20-22), 2·7-fold higher astaxanthin level (0·69 vs 0·25 μg g^-1 shrimp), 34% higher weight gain (7·18 vs 5·32 g shrimp^-1 ), and 85% higher phenoloxidase activity (OD490  = 0·265 vs 0·143) than shrimp in the control group.

CONCLUSIONS

The result supports the potential use of B. aquimaris SH6 as a feed supplement for promoting the colourization and weight gain, and for enhancing innate immunity of whiteleg shrimp.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates that carotenoids produced by B. aquimaris SH6 can be successfully absorbed and converted to astaxanthin in whiteleg shrimp.

Deficiency of PdxR in Streptococcus mutans affects vitamin B6 metabolism, acid tolerance response and biofilm formation

Streptococcus mutans, a key etiological agent of the human dental caries, lives primarily on the tooth surface in tenacious biofilms. The SMU864 locus, designated pdxR, is predicted to encode a member of the novel MocR/GabR family proteins, which are featured with a winged helix DNA-binding N-terminal domain and a C-terminal domain highly homologous to the pyridoxal phosphate-dependent aspartate aminotransferases. A pdxR-deficient mutant, TW296, was constructed using allelic exchange. PdxR deficiency in S. mutans had little effect on cell morphology and growth when grown in brain heart infusion. However, when compared with its parent strain, UA159, the PdxR-deficient mutant displayed major defects in acid tolerance response and formed significantly fewer biofilms (P < 0.01). When analyzed by real-time polymerase chain reaction, PdxR deficiency was found to drastically reduce expression of an apparent operon encoding a pyridoxal kinase (SMU865) and a pyridoxal permease (SMU866) of the salvage pathway of vitamin B6 biosynthesis. In addition, PdxR deficiency also altered the expression of genes for ClpL protease, glucosyltransferase B and adhesin SpaP, which are known to play important roles in stress tolerance and biofilm formation. Consistently, PdxR-deficiency affected the growth of the deficient mutant when grown in defined medium with and without vitamin B6 . Further studies revealed that although S. mutans is known to require vitamin B6 to grow in defined medium, B6 vitamers, especially pyridoxal, were strongly inhibitory at millimolar concentrations, against S. mutans growth and biofilm formation. Our results suggest that PdxR in S. mutans plays an important role in regulation of vitamin B6 metabolism, acid tolerance response and biofilm formation.

Negative regulation of signal transducer and activator of transcription-3 signalling cascade by lupeol inhibits growth and induces apoptosis in hepatocellular carcinoma cells

Background:

Constitutive activation of signal transducer and activator of transcription signalling 3 (STAT3) has been linked with survival, proliferation and angiogenesis in a wide variety of malignancies including hepatocellular carcinoma (HCC).

Methods:

We evaluated the effect of lupeol on STAT3 signalling cascade and its regulated functional responses in HCC cells.

Results:

Lupeol suppressed constitutive activation of STAT3 phosphorylation at tyrosine 705 residue effectively in a dose- and time-dependent manner. The phosphorylation of Janus-activated kinases (JAKs) 1 and 2 and Src was also suppressed by lupeol. Pervanadate treatment reversed the downregulation of phospho-STAT3 induced by lupeol, thereby indicating the involvement of a phosphatase. Indeed, we observed that treatment with lupeol increased the protein and mRNA levels of SHP-2, and silencing of SHP-2 abolished the inhibitory effects of lupeol on STAT3 activation. Treatment with lupeol also downregulated the expression of diverse STAT3-regulated genes and decreased the binding of STAT3 to VEGF promoter. Moreover, the proliferation of various HCC cells was significantly suppressed by lupeol, being associated with substantial induction of apoptosis. Depletion of SHP-2 reversed the observed antiproliferative and pro-apoptotic effects of lupeol.

Conclusions:

Lupeol exhibited its potential anticancer effects in HCC through the downregulation of STAT3-induced pro-survival signalling cascade.

Transcriptome analysis of LuxS-deficient Streptococcus mutans grown in biofilms

We previously reported that LuxS in Streptococcus mutans is involved in stress tolerance and biofilm formation. In this study, flowcells and confocal laser scanning microscopy were used to further examine the effects of LuxS-deficiency on biofilm formation. Similar to the wild-type strain (UA159), a strain deficient in LuxS (TW26D) bound efficiently to the flowcells and formed microcolonies 4 h after inoculation. Unlike UA159, which accumulated and formed compact, evenly distributed biofilms after 28 h, TW26D showed only loose, sporadic, thin biofilms. DNA microarray analysis revealed alterations in transcription of more than 60 genes in TW26D biofilms by at least 1.5-fold (P < 0.001). Among the upregulated genes were those for sugar-specific enzymes II of the phosphotransferase (PTS) system and the atp operon, which codes for the proton-pumping F-ATPase. Of the downregulated genes, several encode proteins with putative functions in DNA repair. Mutation of selected genes caused severe defects in the ability of the mutants to tolerate low pH and oxidative stress. These results provide additional proof that LuxS-deficiency causes global alterations in the expression of genes central to biofilm formation and virulence of S. mutans, including those involved in energy metabolism, DNA repair and stress tolerance.

A simple purification method and morphology and component analyses for carotovoricin Er, a phage-tail-like bacteriocin from the plant pathogen Erwinia carotovora Er

Carotovoricin Er has been isolated as a phage-tail-like bacteriocin from the plant pathogen Erwinia carotovora Er [Kamimiya, S. et al., (1977), Agric. Biol. Chem. 41, 911-912]. However, the fine morphology and structural composition of carotovoricin Er remained to be studied because a large amount of contracted carotovoricin Er were present in the bacteriocin preparations so far obtained. To obtain intact carotovoricin Er and its major parts, we developed simple and efficient purification methods including the use of sucrose density gradient centrifugation in the presence of 10-20% (v/v) ethanol. Electron microscopy for the purified carotovoricin Er showed the presence of a novel antenna-like structure at the proximal end of the phage-tail-like particle, which consisted of a sheath-and-core part, a baseplate, and tail fibers. Contracted sheath and inner core were purified as hollow cylindrical structures with longitudinal lengths of 69 and 174 nm, respectively, and tail fibers were purified as a fibrous structure with length of 63 nm. SDS-polyacrylamide gel electrophoresis showed the presence of single major proteins of 50, 20, and 68 kDa in the isolated sheath, core, and tail fiber, respectively. Three other minor proteins of 46, 44, and 35 kDa were also identified as the structural proteins of carotovoricin Er, which may be the candidate proteins for the antenna-like and the base plate structures. Thus carotovoricin Er consists of at least 6 protein components.

An alternative approach: antegrade catheter-directed thrombolysis in a case of phlegmasia cerulea dolens

Phlegmasia cerulea dolens is an uncommon sequela of severe deep venous thrombosis of the lower extremities. Characterized by massive edema, arterial and venous compromise, and threats to limb and life, this clinical entity is a clear indication for thrombolytic therapy. We report an innovative approach to conventional thrombolysis via a lesser saphenous vein cut-down. This simple technique is a safe, reliable alternative to present methods of achieving deep venous access. Hence, it should be considered as an addition to the treatment armamentarium for massive deep venous thrombosis of the lower extremity.

The wandering coronary stent. Case report

Complications associated with coronary stent placement have decreased in recent years. One of the complications involved with this procedure is the possibility that the stent is stripped from the delivery catheter prior to deployment and is lost systemically. This paper reports a rare complication which resulted in vascular insufficiency necessitating surgical intervention.

[Diagnosis of cardiac failure]

The mere recognition of cardiac failure should not be the sole diagnostic aim. Diagnosis must also include the search for the underlying cause of cardiac failure and for its precipitating causes, as well as the assessment of its severity. Each step is essential because it contributes to the choice of an appropriate treatment. Full diagnosis take into account disease history, physical examination, electrocardiogram and chest X-ray; in addition, informations provided by cardiac echography play an increasing role in the assessment of cardiac failure.

Impact of acute mental stress on sympathetic nerve activity and regional blood flow in advanced heart failure: implications for 'triggering' adverse cardiac events

BACKGROUND

Evidence is accumulating that specific "triggers," such as intense psychological stress, may precipitate myocardial infarction and sudden death. Patients with advanced heart failure have increased resting sympathoexcitation, which has been directly related to increased mortality. The impact of triggers on sympathetic nerve activity and regional blood flow in heart failure has not been examined in patients with heart failure.

METHODS AND RESULTS

Twenty-seven patients with heart failure (NYHA functional class III or IV) and 26 age-matched normal control subjects were studied. Muscle sympathetic nerve activity, heart rate, mean arterial pressure, forearm blood flow, and renal blood flow were measured during mental stress testing with mental arithmetic and Stroop color word test. Patients with heart failure had elevated levels of resting muscle sympathetic nerve activity and heart rate. Mental stress significantly increased muscle sympathetic nerve activity and heart rate in both patients with heart failure and control subjects, although the magnitude of increases tended to be blunted in patients with heart failure. Nevertheless, absolute levels of sympathetic activity in patients with heart failure remained significantly higher than levels in control subjects during mental stress. The decrease in renal blood flow in patients with heart failure was similar to that of control subjects, despite greater resting renal vasoconstriction. The increase in forearm blood flow during mental stress testing in patients with heart failure was blunted compared with that of control subjects.

CONCLUSIONS

Patients with heart failure do not have augmented muscle sympathetic nerve activity responses to mental stress, despite elevated resting levels of sympathetic activity, but they do have markedly higher absolute levels of sympathetic nerve activity during mental stress as well as at rest.

Modulation of renal cortical blood flow during static exercise in humans

During static exercise, several reflex systems that increase sympathetic nerve activity, heart rate, arterial pressure, and cardiac output are activated. At rest, the renal circulation receives the most blood flow per tissue weight of any organ in the body. However, the renal circulatory response to static exercise has not been studied in humans because of technical limitations in methods for measuring rapid changes in renal blood flow. The aim of this study was to determine the renal blood flow response to static exercise in healthy humans and, specifically, to clarify the reflex mechanisms underlying this response. Renal cortical blood flow was measured using dynamic positron emission tomography and the blood flow agent oxygen-15 water. Graded handgrip exercise, posthandgrip circulatory arrest, and administration of intra-arterial adenosine were performed to clarify the mechanisms controlling renal blood flow during static exercise. The major new findings in this study are that in healthy humans (1) renal cortical blood flow decreases (basal versus handgrip, 4.4 +/- 0.1 versus 3.5 +/- 0.1 mL.min-1.g-1; P = .008) and renal cortical vascular resistance increases (basal versus handgrip, 17 +/- 1 versus 26 +/- 2 U; P = .01) in response to static handgrip exercise; (2) central command and/or the mechanoreflex contributes importantly to the early decrease in renal blood flow (basal versus handgrip, 4.2 +/- 0.2 versus 3.5 +/- 0.3 mL.min-1.g-1; P = .04) and to the increase in renal cortical vascular resistance (basal versus handgrip, 20 +/- 1 versus 25 +/- 2 U; P = .04); (3) the muscle metaboreflex contributes to further decreases in renal blood flow (basal versus posthandgrip circulatory arrest, 4.3 +/- 0.1 versus 3.5 +/- 0.2 mL.min-1.g-1; P = .002) and increases in renal cortical vascular resistance (basal versus handgrip, 18 +/- 1 versus 25 +/- 3 U; P = .002); and (4) exogenous adenosine activates the muscle metaboreflex producing reflex renal vasoconstriction and decreased renal blood flow, which may implicate endogenous adenosine generated during ischemic exercise as a potential activator of the muscle metaboreflex during ischemic handgrip exercise.

Dynamics of muscle sympathetic nerve activity in advanced heart failure patients

Muscle sympathetic nerve activity (MSNA) is increased in patients with heart failure compared with healthy subjects. We applied spectral and correlation techniques to determine if qualitative as well as quantitative differences in MSNA differentiate heart failure patients from healthy subjects. We recorded MSNA, heart rate, and respiration in 11 heart failure patients and 10 healthy humans. Our results are as follows. 1) Statistically significant low-frequency modulation of MSNA at 0.029 +/- 0.002 Hz (mean +/- SE; range 0.026-0.038 Hz) was found in 10 of 11 heart failure patients but in only 2 of 10 healthy controls (differences between groups, P < 0.01; chi 2 test). 2) Heart rate and respiration also demonstrated significant low-frequency modulation in a similar range. 3) Spectral and correlation techniques revealed that low-frequency modulation of MSNA was highly correlated with low-frequency modulation of respiration in heart failure patients, but not in healthy subjects. In contrast, low-frequency modulation of MSNA did not correlate well with low-frequency modulation of heart rate. In summary, low-frequency modulation of respiration is coupled to low-frequency modulation of MSNA in heart failure patients, but not in normal subjects. We speculate that this low-frequency modulation of respiration may represent subclinical Cheyne-Stokes breathing, which has marked qualitative effects on MSNA in patients with heart failure.

Venous hemodynamics during impulse foot pumping

PURPOSE

This study was designed to measure the effect of intermittent pneumatic compression of the plantar venous plexus on popliteal vein (PV) and common femoral vein (CFV) velocities measured by duplex ultrasound scanning.

METHODS

Thirty lower limbs in 15 healthy volunteers had venous duplex scanning measurement of PV and CFV velocities before and during foot pumping with an arteriovenous impulse foot pump system. Venous velocities were measured at two pump pressure settings (100 mm Hg, 200 mm Hg) and during two pump impulse durations (short = 1 second, normal = 3 seconds). All limbs were examined with the subjects in the supine position, and then measurements were repeated with subjects in the 15-degree reverse Trendelenburg position. The mean maximum venous velocity (MVV) produced by foot pumping was compared with resting venous velocity at each anatomic location and for each technologic variable.

RESULTS

Impulse foot pumping produced a statistically significant increase in MVV in both the PV and the CFV compared with resting velocities. This significant increase was observed for both pressure settings and both impulse durations, and no differences produced by these two individual variables could be detected. The increase in MVV produced by foot pumping was similar for limbs in the supine position and those examined in the reverse Trendelenburg position. The percentage increase in MVV produced by foot pumping was significantly higher in the PV than in the CFV.

CONCLUSIONS

Intermittent pneumatic compression of the plantar venous plexus produces measurable increases in venous outflow from the lower limbs of normal subjects. This study seems to justify further evaluation of the effectiveness of this technique for mechanical deep venous thrombosis prophylaxis in selected high-risk patient groups.

Model control of image processing: pupillometry

Smart instruments require on-line computers, special purpose hardware, or both. A pupillometer is described that relies only on a general purpose microcomputer with a frame grabber to process infrared video camera pictures of the human eye. An essential feature of the instrument is that a top-down model controls the image processing algorithms. The model generates regions of interest, ROIs, positioned from knowledge of anatomy and optics of the eye and information from previously analyzed frames. Within these adaptively controlled ROIs, fast, run-time algorithms automatically calculate local thresholds, area measurements, moments for centroid position information, and use pyramiding to shorten calculation time for large pupils. Outputs are precise measurements of pupil size and eye position in real time, with adequate bandwidth for most purposes.

DNA modification induced during infection of Bacillus subtilis by phage phi 3T

The DNA of the Bacillus subtilis temperate phage phi 3T is not susceptible to cleavage by the restriction endonuclease HaeIII, although it is cut by many other restriction enzymes. The host DNA from uninfected cells is cut by HaeIII. We show that phi 3T DNA propagated in a restriction-modification-defective Escherichia coli cell can be digested by HaeIII. Thus, phi 3T DNA does contain the nucleotide recognition sequence of HaeIII. We suggest that this phage induces the modification of its own DNA. In support of this mechanism we show that extracts prepared from phi 3T-infected cells contain an activity which in the presence of S-adenosyl-L-methionine (SAM) can modify lambda DNA against cleavage by HaeIII. The same in vitro-modified DNA is still susceptible to cleavage by other restriction endonucleases.