Computational infrared and Raman spectra by hybrid QM/MM techniques: a study on molecular and catalytic material systems.

Vibrational spectroscopy is one of the most well-established and important techniques for characterizing chemical systems. To aid the interpretation of experimental infrared and Raman spectra, we report on recent theoretical developments in the ChemShell computational chemistry environment for modelling vibrational signatures. The hybrid quantum mechanical and molecular mechanical approach is employed, using density functional theory for the electronic structure calculations and classical forcefields for the environment. Computational vibrational intensities at chemical active sites are reported using electrostatic and fully polarizable embedding environments to achieve more realistic vibrational signatures for materials and molecular systems, including solvated molecules, proteins, zeolites and metal oxide surfaces, providing useful insight into the effect of the chemical environment on the signatures obtained from experiment. This work has been enabled by the efficient task-farming parallelism implemented in ChemShell for high-performance computing platforms.  This article is part of a discussion meeting issue 'Supercomputing simulations of advanced materials'.

Multiscale QM/MM modelling of catalytic systems with ChemShell.

Hybrid quantum mechanical/molecular mechanical (QM/MM) methods are a powerful computational tool for the investigation of all forms of catalysis, as they allow for an accurate description of reactions occurring at catalytic sites in the context of a complicated electrostatic environment. The scriptable computational chemistry environment ChemShell is a leading software package for QM/MM calculations, providing a flexible, high performance framework for modelling both biomolecular and materials catalysis. We present an overview of recent applications of ChemShell to problems in catalysis and review new functionality introduced into the redeveloped Python-based version of ChemShell to support catalytic modelling. These include a fully guided workflow for biomolecular QM/MM modelling, starting from an experimental structure, a periodic QM/MM embedding scheme to support modelling of metallic materials, and a comprehensive set of tutorials for biomolecular and materials modelling.

Laparoscopic and robot-assisted suture versus mesh hysteropexy: a retrospective comparison.

INTRODUCTION AND HYPOTHESIS: Our study was aimed at comparing the outcomes of laparoscopic and robot-assisted laparoscopic suture-based hysteropexy (SutureH) versus sacral hysteropexy using mesh (MeshH) for bothersome uterine prolapse. Our hypothesis is that MeshH is more successful and provides better uterine support than SutureH. METHODS: A retrospective cohort study of 228 consecutive women who underwent re-suspension of the uterus using uterosacral ligaments (SutureH n=97) or a "U-shaped" mesh from the sacral promontory (MeshH, n=132). Surgery was performed by laparoscopy or robot-assisted laparoscopy. Subjects were assessed at baseline, 1 year, and beyond 1 year. The null hypothesis, that SutureH and MeshH have similar success, was based on a composite outcome ("composite success"), and that they provide the same level of uterine support, was based on POP-Q point C at 1 year. "Composite success" was defined as: POP-Q point C above the hymen; absence of a vaginal bulge; no repeat uterine prolapse surgery or pessary placement. Other outcomes included improvement in symptomology using Patient Global Impression of Improvement, POP-Q point C change and complications. RESULTS: Follow-up data were available for 191 out of 228 women. "Composite success" was not significantly different between MeshH and SutureH groups (81.7% vs 84.5%, p=0.616). MeshH provided better elevation of the uterus than SutureH (point C change: -7.38cm vs -6.99cm; p<0.001). Similar symptom improvement and low complications occurred in both groups. CONCLUSIONS: Laparoscopic and robot-assisted laparoscopic suture hysteropexy and mesh sacral hysteropexy provide women with minimally invasive, durable surgical options for uterine preservation. "Composite success" was similar in the two groups, but MeshH provided better uterine support than SutureH. However, SutureH gives women an effective mesh-free option.

The structural pathway from its solvated molecular state to the solution crystallisation of the α- and ß-polymorphic forms of para amino benzoic acid.

Para amino benzoic acid (PABA) has two well-characterised α- and ß-polymorphic forms and, whilst both crystallise in the monoclinic space group P21/n, they have quite different crystal chemistry and crystallisability behaviour. Previous work has shown that the molecular conformation deformation energy in the crystalline state is higher for the ß-form than for the α-form and that the lattice energy for the former converges more slowly than for the latter overall. This suggests that not only is there a higher barrier to crystallisation for the ß-form but also that low solution supersaturations might be needed for it to preferentially nucleate. Additionally, solute cluster propensity and solute solvation energetic analysis highlight the importance of an aqueous solvation environment in inhibiting the α-form's strong OH⋯O carboxylic acid hydrogen bond (H-bond) dimer. Despite this, the detailed molecular-scale pathway from solvated molecules to 3D crystallographic structure still remains unclear, most notably regarding how the nucleation process is activated and how, as a result, this mediates the preferential formation of either of the two polymorphic forms. Molecular dynamics (MD) simulations coupled with FTIR studies and intermolecular synthon analysis address this issue through characterisation of the propensity of the incipient bulk synthons that are important in the crystallisation of the two polymorphic forms within the solution state. MD molecular trajectory analysis within crystallisation solutions reveals a greater propensity for OH⋯O synthons (both single H-bonds and homodimers) typical of the α-form and NH⋯O synthons found in both the α- and ß-forms when compared to aqueous solution but much lower propensities for the ß-form's "fingerprinting" OH⋯N and π-π stacking synthons. In contrast, data from the aqueous solution environment reveals a much greater propensity for the ß-form's π-π interaction synthons. IR dilution studies in acetonitrile in the carbonyl region reveal the presence of two CO vibrational stretching bands, whose relative intensities vary as a function of solution dilution. These were assigned to the solvated PABA monomer and a COOH dimer of PABA. Similar data in ethanol shows a main CO stretching band with a shoulder peak suggesting a similar monomer vs. dimer speciation may exist in this solvent. The IR data is consistent with the organic solvent MD data, albeit the corresponding analysis for the aqueous solution was precluded due to the latter's strong OH vibrational mode which restricted validation in aqueous solutions.

Polyguluronate simulations shed light onto the therapeutic action of OligoG CF-5/20.

Chronic mucoid P. aeruginosa cystic fibrosis (CF) lung infections are associated with the development of a biofilm composed of anionic acetylated exopolysaccharide (EPS) alginate, electrostatically stabilised by extracellular Ca2+ ions. OligoG CF-5/20, a low molecular weight guluronate rich oligomer, is emerging as a novel therapeutic capable of disrupting mature P. aeruginosa biofilms. However, its method of therapeutic action on the mucoid biofilm EPS is not definitively known at a molecular level. This work, utilising molecular dynamics (MD) and Density-Functional Theory (DFT), has revealed that OligoG CF-5/20 interaction with the EPS is facilitated solely through bridging Ca2+ ions, which are not liberated from their native EPS binding sites upon OligoG CF-5/20 dispersal, suggesting that OligoG CF-5/20 does not cause disruptions to mature P. aeruginosa biofilms through breaking EPS-Ca2+-EPS ionic cross-links. Rather it is likely that the therapeutic activity arises from sequestering free Ca2+ ions and preventing further Ca2+ induced EPS aggregation.

Combining quasielastic neutron scattering and molecular dynamics to study methane motions in ZSM-5.

Quasi-elastic neutron scattering (QENS) and molecular dynamics (MD) simulations are applied in combination to investigate the dynamics of methane in H-ZSM-5 zeolite catalysts used for methanol-to-hydrocarbons reactions. Methane is employed as an inert model for the methanol reaction feedstock, and studies are made of the fresh catalyst and used catalysts with varying levels of coke buildup to investigate the effect of coking on reactant mobility. Measurements are made in the temperature range from 5 to 373 K. Methane mobility under these conditions is found to be extremely high in fresh ZSM-5, with the majority of movements occurring too fast to be resolved by the QENS instrument used. A small fraction of molecules undergoing jump diffusion on QENS time scales is identified and found to correspond with short-range jump diffusion within single zeolite pores as identified in MD simulations. Agreement between QENS and MD mobility measurements is found to be within 50%, validating the simulation approach employed. Methane diffusion is found to be minimally affected by moderate levels of coke buildup, while highly coked samples result in the confinement of methane to single pores within the zeolite with minimal long-range diffusion.

White shrimp Litopenaeus vannamei that have received mixtures of heat-killed and formalin-inactivated Vibrio alginolyticus and V. harveyi exhibit recall memory and show increased phagocytosis and resistance to Vibrio infection.

Heat-killed Vibrio alginolyticus (HVa), formalin-inactivated V. alginolyticus (FVa), heat-killed Vibrio harveyi (HVh), formalin-inactivated V. harveyi (FVh), live V. alginolyticus (LVa), and live V. harveyi (LVh) were used in this study. White shrimp Litopenaeus vannamei receiving two mixtures (HVa + FVa) or four mixtures (HVa + FVa + HVh + FVh) served as primary exposure, and shrimp receiving LVa or LVh afterward served as secondary exposure. Shrimp receiving marine saline and then receiving either LVa or LVh served as controls. Phagocytic activity and clearance efficiency were examined in shrimp that received two mixtures after 1-8 weeks and then received LVa. Both the phagocytic activity and clearance efficiency of shrimp receiving two mixtures were significantly higher than in control shrimp after 1-8 weeks. In another experiment, phagocytic activity and clearance efficiency were examined in shrimp that received four mixtures after 1-8 weeks and then received LVa and LVh, respectively. The phagocytic activity of shrimp receiving four mixtures was significantly higher than in control shrimp after 1-8 weeks post exposure to LVa and LVh. The clearance efficiency of shrimp receiving four mixtures was significantly higher than in control shrimp after 1-6 weeks post exposure to LVa, and 1-7 weeks post exposure to LVh. In the other experiment, the survival rate of shrimp that received four mixtures after five weeks were challenged with LVa at 6.4 × 107 colony-forming units (cfu) shrimp-1 and LVh at 4.4 × 106 cfu shrimp-1. Shrimp that received marine saline for five weeks and then challenged with LVa and LVh at a same dose served as challenged controls. The survival rate of shrimp that received four mixtures was significantly higher (90%) than that of control shrimp (67%), and significantly higher (73%) than that of control shrimp (53%) after 3-7 days post challenge with LVa and LVh. It is concluded that the mixtures have feature of adjuvant and antigen, and shrimp receiving mixtures of heat-killed and formalin-inactivated V. alginolyticus and V. harveyi even after 5-8 weeks exhibit memory recall and show increased phagocytosis and resistance to Vibrio infections.

Determinants of Newly-Diagnosed Raised Blood Pressure: The Malaysian Context.

BACKGROUND: Raised blood pressure, also known as hypertension (HPT), has been a distressing health concern among Malaysians. An upward trend is found on the prevalence of newly-diagnosed HPT, contributing to the high number of overall hypertensive patients in Malaysia. To understand the cause and reduce the economic burden caused by HPT, current research aims to examine the dependency among sociodemographic and behavioural determinants of newly-diagnosed HPT among Malaysians. METHODS: The current study uses secondary data from the Fifth National Health and Morbidity Survey (NHMS V) 2015, a population based cross-sectional study. This study uses the Bayesian Network (BN) modelling to design and build a 'causal' model and identify potential determinants and their respective conditional probability on the prevalence of newly-diagnosed HPT among Malaysians. RESULTS: This study shows that Malaysians with newly-diagnosed HPT are directly affected by the age and body mass index (BMI). Additionally, household income, sex, marital status, ethnicity, strata, education levels, occupation, fruit intake, vegetable intake, smoking status, physical activity and plain water intake indirectly affect the incidence of the newly-diagnosed HPT. CONCLUSION: These results may be helpful in implementing appropriate policies to prevent and monitor the increasing prevalence of newly-diagnosed HPT among adults in Malaysia.

Nutritional and bone health status in young men with mild-to-moderate intellectual disability and without intellectual disability residing in community setting in Malaysia.

BACKGROUND: This study aimed to compare the nutritional and bone health status between young men with mild-to-moderate intellectual disability and those without intellectual disability and to determine predictors for their bone health status. METHOD: A total of 95 men (47 men with intellectual disability; 48 men without intellectual disability), aged 20-39 years, participated in this study. Anthropometric profile, dietary intake, physical activity level and calcaneal speed of sound (SOS) were collected. RESULTS: The men with intellectual disability had moderate diet quality whilst the men without intellectual disability had poor diet quality. More participants with intellectual disability (97.9%) were inactive compared with their counterparts (10.4%). The SOS value was similar between groups and was lower than the reference. Increasing age and low physical activity level were negative predictors for bone health status. CONCLUSION: Both young men with and without intellectual disability have suboptimal nutritional and bone health status. Strategies to improve their nutritional and bone health status are warranted.

Scalable Graphene-Based Membranes for Ionic Sieving with Ultrahigh Charge Selectivity.

Nanostructured graphene-oxide (GO) laminate membranes, exhibiting ultrahigh water flux, are excellent candidates for next generation nanofiltration and desalination membranes, provided the ionic rejection could be further increased without compromising the water flux. Using microscopic drift-diffusion experiments, we demonstrated the ultrahigh charge selectivity for GO membranes, with more than order of magnitude difference in the permeabilities of cationic and anionic species of equivalent hydration radii. Measuring diffusion of a wide range of ions of different size and charge, we were able to clearly disentangle different physical mechanisms contributing to the ionic sieving in GO membranes: electrostatic repulsion between ions and charged chemical groups; and the compression of the ionic hydration shell within the membrane's nanochannels, following the activated behavior. The charge-selectivity allows us to rationally design membranes with increased ionic rejection and opens up the field of ion exchange and electrodialysis to the GO membranes.

A QM/MM Study of Nitrite Binding Modes in a Three-Domain Heme-Cu Nitrite Reductase.

Copper-containing nitrite reductases (CuNiRs) play a key role in the global nitrogen cycle by reducing nitrite (NO2-) to nitric oxide, a reaction that involves one electron and two protons. In typical two-domain CuNiRs, the electron is acquired from an external electron-donating partner. The recently characterised Rastonia picketti (RpNiR) system is a three-domain CuNiR, where the cupredoxin domain is tethered to a heme c domain that can function as the electron donor. The nitrite reduction starts with the binding of NO2- to the T2Cu centre, but very little is known about how NO2- binds to native RpNiR. A recent crystallographic study of an RpNiR mutant suggests that NO2- may bind via nitrogen rather than through the bidentate oxygen mode typically observed in two-domain CuNiRs. In this work we have used combined quantum mechanical/molecular mechanical (QM/MM) methods to model the binding mode of NO2- with native RpNiR in order to determine whether the N-bound or O-bound orientation is preferred. Our results indicate that binding via nitrogen or oxygen is possible for the oxidised Cu(II) state of the T2Cu centre, but in the reduced Cu(I) state the N-binding mode is energetically preferred.

Decolorization and mineralization of Amaranth dye using multiple zoned aerobic and anaerobic baffled constructed wetland.

The objective of this study is to determine the reduction efficiency of Chemical Oxygen Demand (COD) as well as the removal of color and Amaranth dye metabolites by the Aerobic-anaerobic Baffled Constructed Wetland Reactor (ABCW). The ABCW reactor was planted with common reed (Phragmite australis) where the hydraulic retention time (HRT) was set to 1 day and was fed with synthetic wastewater with the addition of Amaranth dye. Supplementary aeration was supplied in designated compartments of the ABCW reactor to control the aerobic and anaerobic zones. After Amaranth dye addition the COD reduction efficiency dropped from 98 to 91% while the color removal efficiency was 100%. Degradation of azo bond in Amaranth dye is shown by the UV-Vis spectrum analysis which demonstrates partial degradation of Amaranth dye metabolites. The performance of the baffled unit is due to the longer pathway as there is the up-flow and down-flow condition sequentially, thus allowing more contact of the wastewater with the rhizomes and micro-aerobic zones.

DL_ANALYSER Notation for Atomic Interactions (DANAI): A Natural Annotation System for Molecular Interactions, Using Ethanoic Acid Liquid as a Test Case.

The DL_ANALYSER Notation for Atomic Interactions, DANAI, is the notation syntax to describe interactions between molecules. This notation can annotate precisely the detailed atomistic interactions without having to resolve to diagrammatic illustrations, and yet can be interpreted easily by both human users and computational means. By making use of the DL_F Notation, a universal atom typing scheme for molecular simulations, DANAI contains the expression of atomic species in a natural chemical sense. It is implemented within DL_ANALYSER, a general analysis software program for DL_POLY molecular dynamics simulation software. By making references to the molecular dynamics simulations of pure ethanoic acid liquid, it is shown that DL_ANALYSER can identify and distinguish a variety of hydrogen bond and hydrophobic contact networks through the use of the DANAI expression. It was found that the carboxylic groups preferentially orientated in a "head-to-tail" conformation to form hydrogen bonds between the carbonyl oxygen and hydroxyl hydrogen, resulting in a series of linear structures that intertwined with pockets of methyl clusters.

Descriptions and Implementations of DL_F Notation: A Natural Chemical Expression System of Atom Types for Molecular Simulations.

DL_F Notation is an easy-to-understand, standardized atom typesetting expression for molecular simulations for a range of organic force field (FF) schemes such as OPLSAA, PCFF, and CVFF. It is implemented within DL_FIELD, a software program that facilitates the setting up of molecular FF models for DL_POLY molecular dynamics simulation software. By making use of the Notation, a single core conversion module (the DL_F conversion Engine) implemented within DL_FIELD can be used to analyze a molecular structure and determine the types of atoms for a given FF scheme. Users only need to provide the molecular input structure in a simple xyz format and DL_FIELD can produce the necessary force field file for DL_POLY automatically. In commensurate with the development concept of DL_FIELD, which placed emphasis on robustness and user friendliness, the Engine provides a single-step solution to setup complex FF models. This allows users to switch from one of the above-mentioned FF seamlessly to another while at the same time provides a consistent atom typing that is expressed in a natural chemical sense.

Posterior vaginal compartment repairs: Where are the main anatomical defects?

INTRODUCTION AND HYPOTHESIS: Traditionally, it has been believed that posterior vaginal compartment prolapse was largely due to defects in the rectovaginal fascia, with surgical repairs concentrating on addressing this defect. We aimed to determine the relative size of defects at the different vaginal levels (I-III) following a large number of posterior vaginal compartment repairs (PRs) to determine whether this traditional viewpoint is still appropriate. METHODS: In a cross-sectional study of 300 consecutive PRs, mostly following prior or concomitant hysterectomy, two sets of markers of posterior compartment prolapse were used to measure anatomical defects at levels I-III: (i) from Pelvic Organ Prolapse Quantification (POP-Q) system points C, Ap, Bp, and genital hiatus (GH), and from Posterior Repair Quantification (PR-Q) perineal gap (PG), posterior vaginal-vault descent (PVVD), midvaginal laxity (MVL)-vault undisplaced, and rectovaginal fascial laxity (RVFL). RESULTS: The largest defects were found at level I (PVVD: mean 6.0 cm; point C, mean minus 0.9 cm), and level III (PG, mean 2.9 cm; GH, mean 3.7 cm). Level II defects (MVL-vault undisplaced, mean 1.3 cm; RVFL, mean 1.1 cm; points Ap, Bp, both mean 1.0 cm) were relatively small. CONCLUSIONS: This study suggests that the defects found at surgery for posterior vaginal compartment prolapse were more frequent at the vaginal vault (level I) and vaginal introitus (level III) than at midvagina (level II). These findings should have implications for surgical planning.

Posterior Circulation Ischemic Stroke Caused by Arterial Dissection: Characteristics and Predictors of Poor Outcomes.

BACKGROUND: Posterior circulation ischemic stroke (PCS) caused by arterial dissection (AD-PCS) was rarely discussed. The present study aimed to evaluate the clinical characteristics and predictors of poor outcomes in AD-PCS patients. METHODS: A total of 286 PCS patients were recruited from Taipei Veterans General Hospital Stroke Registry (between January 1, 2012 and February 28, 2014). Clinical/image data of recruited PCS patients were reviewed by stroke specialists who reached a consensus on the stroke etiologies. Data of AD-PCS patients were analyzed. RESULTS: Seventy-four patients (65.8 ± 15.6 years, 56 (75.7%) men) were determined as AD-PCS. Headache and neck pain at admission were only presented in 18.9 and 6.8% of patients, respectively. The location of AD was initiated in the vertebral artery (66.2%), basilar artery (27.0%), posterior inferior cerebellar artery (5.4%) and posterior cerebral artery (1.4%). The involvement of intracranial arteries was present in the majority of patients (97.3%). Of the patients, 9.5% died, and 29.7% had poor functional outcomes (modified Rankin Scale ≥4) at 3-month. Conscious change independently predicted mortality at 3 months. Quadriparesis, National Institutes of Health Stroke Scale (NIHSS) score >8 and infarct lesions involving >1 category were independent predictors for poor functional outcomes at 3 months. CONCLUSION: AD is an important etiology of PCS. Physicians should be more vigilant in recognizing AD-PCS. Intracranial arteries are more important in AD-PCS; very few patients of AD-PCS had dissection solely in extracranial arteries. Short-term outcomes of AD-PCS were not favorable. Conscious change, quadriparesis, NIHSS score >8 and infarct lesions involving >1 category were independent predictors for poor outcomes. Patients presenting these factors should be monitored closely.

Activation of immunity, immune response, antioxidant ability, and resistance against Vibrio alginolyticus in white shrimp Litopenaeus vannamei decrease under long-term culture at low pH.

The growth, activation of immunity, immune parameters, and transcript levels of cytMnSOD, mtMnSOD, ecCuZnSOD, glutathione peroxidase (GPx), catalase, lysozyme, and penaeidin 3a were examined in white shrimp Litopenaeus vannamei reared at pH 6.8 and 8.1 after 24 weeks. No significant difference in growth was observed between the two groups. An in vitro study indicated that phenoloxidase activity and respiratory bursts (RB, release of the superoxide anion) were significantly higher in the haemocytes of pH 8.1 shrimp (shrimp reared at pH 8.1) than in pH 6.8 shrimp (shrimp reared at pH 6.8). An in vivo study indicated that the levels of immune parameters of pH 8.1 shrimp were significantly higher than in pH 6.8 shrimp, and the transcript levels of cytMnSOD, ecCuZnSOD, glutathione peroxidase, lysozyme, and penaeidin 3a were down-regulated in pH 6.8 shrimp. In another experiment, shrimp reared at pH 6.8 and 8.1 for 24 weeks were challenged with Vibrio alginolyticus. The mortality rate of pH 6.8 shrimp was significantly higher than in pH 8.1 shrimp over 12-168 h. Phagocytic activity, phagocytic index, and clearance efficiency to V. alginolyticus were significantly lower in pH 6.8 shrimp. We concluded that shrimp under long-term culture at pH 6.8 exhibited decreased resistance against V. alginolyticus as evidenced by reductions in the activation of immunity and immune parameters together with decreased transcript levels of cytMnSOD, ecCuZnSOD, GPx, lysozyme, and penaeidin 3a.

Crowding of white shrimp Litopenaeus vananmei depresses their immunity to and resistance against Vibrio alginolyticus and white spot syndrome virus.

Immunity parameters and the expression levels of several immune-related proteins, including lipopolysaccharide and ß-glucan binding protein (LGBP), peroxinectin (PX), intergin ß (IB), prophenoloxidase (proPO) I, proPO II, α2-macroglobulin (α2-M), cytosolic mangangese superoxide dismutase (cytMnSOD), mitochondria manganese superoxide dismutase (mtMnSOD), catalase, glutathione peroxidase (GPx), lysozyme, and penaeidin 3a were examined in white shrimp Litopenaeus vannamei reared at stocking densities of 2, 10, 20, 30, and 40 shrimp L(-1) after 3, 6, and 12 h. All immune parameters including haemocyte count, phenoloxidase (PO) activity, respiratory burst (RB), superoxide dismutase (SOD) activity, lysozyme activity, and haemolymph protein were negatively related to density and time. The PO activity, SOD activity, and lysozyme activity of shrimp reared at 10 shrimp L(-1) after 12 h significantly decreased. The transcript levels of these immune-related proteins were down-regulated in shrimp reared at 20, 30, and 40 shrimp L(-1) after 12 h. Phagocytic activity and clearance efficiency to Vibrio alginolyticus were significantly lower in shrimp reared at 30 and 40 shrimp L(-1) after 12 h. The mortality rates of shrimp reared at 20 and 40 shrimp L(-1) were significantly higher than shrimp reared at 2 shrimp L(-1) over 12-144 h and 12-48 h, respectively. Shrimp reared at high densities (>10 shrimp L(-1)) exhibited decreased resistance against pathogens as evidenced by reductions in immune parameters together with decreased expression levels of immune-related proteins, indicating perturbations of the immune system.

White Shrimp Litopenaeus vannamei That Have Received Gracilaria tenuistipitata Extract Show Early Recovery of Immune Parameters after Ammonia Stressing.

White shrimp Litopenaeus vannamei immersed in seawater (35‰) containing Gracilaria tenuistipitata extract (GTE) at 0 (control), 400, and 600 mg/L for 3 h were exposed to 5 mg/L ammonia-N (ammonia as nitrogen), and immune parameters including hyaline cells (HCs), granular cells (GCs, including semi-granular cells), total hemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, lysozyme activity, and hemolymph protein level were examined 24~120 h post-stress. The immune parameters of shrimp immersed in 600 mg/L GTE returned to original values earlier, at 96~120 h post-stress, whereas in control shrimp they did not. In another experiment, shrimp were immersed in seawater containing GTE at 0 and 600 mg/L for 3 h and examined for transcript levels of immune-related genes at 24 h post-stress. Transcript levels of lipopolysaccharide and ß-1,3-glucan binding protein (LGBP), peroxinectin (PX), cytMnSOD, mtMnSOD, and HSP70 were up-regulated at 24 h post-stress in GTE receiving shrimp. We concluded that white shrimp immersed in seawater containing GTE exhibited a capability for maintaining homeostasis by regulating cellular and humoral immunity against ammonia stress as evidenced by up-regulated gene expression and earlier recovery of immune parameters.

Shrimp that have received carrageenan via immersion and diet exhibit immunocompetence in phagocytosis despite a post-plateau in immune parameters.

The effect of carrageenan on the immune response of white shrimp Litopenaeus vannamei, was studied in vitro and in vivo. Shrimp haemocytes receiving carrageenan at 1 mg ml⁻¹ experienced change in cell size, reduction in cell viability, increase in PO activity, serine proteinase activity, and RB in vitro. Shrimp received carrageenan via immersion at 200, 400 and 600 mg L⁻¹ after 3 h and orally at 0.5, 1.0 and 2.0 g kg⁻¹ after 3 weeks showed higher proliferation of haematopoietic tissues (HPTs) together with increases in haemocyte count and other immune parameters. Shrimp that fed a diet containing carrageenan at 0.5 g kg⁻¹ after 3 weeks significantly up-regulated gene expressions of several immune-related proteins. The immune parameters of shrimp that received carrageenan via immersion and orally increased to a plateau after 3 h and after 3 weeks, but decreased after 5 h and 6 weeks, respectively. Phagocytosis and clearance of Vibrio alginolyticus remained high in shrimp that had received carrageenan via immersion after 5 h and orally after 6 weeks, respectively. Resistances of shrimp against V. alginolyticus and white spot syndrome virus were higher over 24-144 h and 72-144 h, respectively in shrimp that received carrageenan at 600 mg L⁻¹ via immersion after 3 and 5 h. It was concluded that carrageenan effectively triggers an innate immunity in vitro, and increases mitotic index of HPT, immune parameters, gene expressions and resistance against pathogens in vivo. Shrimp received carrageenan via immersion and orally exhibited immunocompetence in phagocytosis and clearance of V. alginolyticus, and resistance to pathogen despite the trend in immune parameters to recover to background values.