Genome-wide analysis of ATP-binding cassette (ABC) transporter in Penaeus vannamei and identification of two ABC genes involved in immune defense against Vibrio parahaemolyticus by affecting NF-κB signaling pathway.

The ATP-binding cassette (ABC) transporters have crucial roles in various biological processes such as growth, development and immune defense in eukaryotes. However, the roles of ABC transporters in the immune system of crustaceans remain elusive. In this study, 38 ABC genes were systematically identified and characterized in Penaeus vannamei. Bioinformation analysis revealed that PvABC genes were categorized into ABC A-H eight subfamilies with 17 full-transporters, 11 half transporters and 10 soluble proteins, and multiple immunity-related cis-elements were found in gene promoter regions. Expression analysis showed that most PvABC genes were widely and highly expressed in immune-related tissues and responded to the stimulation of Vibrio parahaemolyticus. To investigate whether PvABC genes mediated innate immunity, PvABCC5, PvABCF1 and PvABCB4 were selected for dsRNA interference experiment. Knockdown of PvABCF1 and PvABCC5 not PvABCB4 increased the cumulative mortality of P. vannamei and bacterial loads in hepatopancreas after infection with V. parahaemolyticus. Further analysis showed that the PvABCF1 and PvABCC5 knockdown decreased expression levels of NF-κB pathway genes and antimicrobial peptides (AMPs). Collectively, these findings indicated that PvABCF1 and PvABCC5 might restrict V. parahaemolyticus challenge by positively regulating NF-κB pathway and then promoting the expression of AMPs, which would contribute to overall understand the function of ABC genes in innate immunity of invertebrates.

Constraints on the maintenance of wild Taxus cuspidata populations based on regression conservation.

To clarify the key factors constraining the maintenance of wild Taxus cuspidata populations and to develop conservation strategies and technical links for current populations, we investigated the renewal status and distribution patterns of wild T. cuspidata populations in the main distribution areas of China. We analyzed the effects of stand factors and human disturbance on population renewal and maintenance. The results showed that the overall regeneration of wild T. cuspidata populations was poor. The basal diameter and height class structure of renewed individuals showed an unhealthy state. 19% of the area was well regenerated. There were three types of regeneration, including poor regeneration with few adult trees, poor regeneration with many adult trees, and good regeneration with few adult trees. The communities in which T. cuspidata was found could be classified into Abies nephrolepis + Tilia amurensis forest, spinney forest, and Picea jezoensis var. microsperma + A. nephrolepis forest. The renewal number of A. nephrolepis + T. amurensis forest was significantly higher than that of spinney forest. Increased stand density and moderate human disturbance contributed to the regeneration of T. cuspidata. The regenerating T. cuspidata seedlings increased significantly when stand density increased from low to medium. The number of regenerating populations in moderately disturbed habitats was significantly higher than those in lightly disturbed habitats. Human disturbance and habitat were currently critical constraints to maintaining and regenerating wild T. cuspidata populations. The conservation of T. cuspidata should consider current status of population regeneration in each habitat patch to develop corresponding in situ conservation and regression conservation measures and focus on the influence of critical factors such as disturbances and habitat conditions.

The variation on structure and immunomodulatory activity of polysaccharide during the longan pulp fermentation.

In the current study, the effects of fermentation manners on the structure and immunomodulatory activity of polysaccharide in longan wine or vinegar were investigated. Compared to longan polysaccharide (CP1), polysaccharide in longan wine (CP2) or vinegar (CP3 and CP4) had smaller molecular weights, and was consisted of more mannose, arabinose, rhamnose, galactose and less glucose. After purification, the major fraction (P1-P4) was obtained from CP1-CP4, respectively. The structures and immunoregulatory activities of P1-P4 were characterized. Fermentation and purification were favorable to increase the immunoregulatory activities of P2-P4, which were contributed to their different structural features. The structure-activity relationship analysis indicated that molecular weight, mannose, rhamnose, glucuronic acid, glucose and arabinose were significantly associated with the cytokines secretion. Compared with other polysaccharides, P3 displayed better immunomodulatory activity due to its lower molecular weight, lower contents of rhamnose and glucose, and higher levels of mannose and arabinose by activating MAPK and PI3K/Akt signaling pathways.

Integrated analysis of physiological, transcriptomic and metabolomic responses and tolerance mechanism of nitrite exposure in Litopenaeus vannamei.

Nitrite accumulation in aquatic environments is a potential risk factor that disrupts multiple physiological functions in aquatic animals. In this study, the physiology, transcriptome and metabolome of the control group (LV-C), nitrite-tolerance group (LV-NT) and nitrite-sensitive group (LV-NS) were investigated to identify the stress responses and mechanisms underlying the nitrite tolerance of Litopenaeus vannamei. After LV-NT and LV-NS were subjected to nitrite stress, the hemocyanin contents were significantly decreased, and hepatopancreas showed severe histological damage compared with LV-C. Likewise, the antioxidant enzymes were also significantly changed after nitrite exposure. The transcriptome data revealed differentially expressed genes associated with immune system, cytoskeleton remodeling and apoptosis in LV-NT and LV-NS. The combination of transcriptomic and metabolomic analysis revealed nitrite exposure disturbed metabolism processes in L. vannamei, including amino acid metabolism, nucleotide metabolism and lipid metabolism. The multiple comparative analysis implicated that higher nitrite tolerance of LV-NT than LV-NS may be attributed to enhanced hypoxia inducible factor-1α expression to regulate energy supply and gaseous exchange. Moreover, LV-NT showed higher antioxidative ability, detoxification gene expression and enhanced fatty acids contents after nitrite exposure in relative to LV-NS. Collectively, all these results will greatly provide new insights into the molecular mechanisms underlying the stress responses and tolerance of nitrite exposure in L. vannamei.

Immune Responses to Gram-Negative Bacteria in Hemolymph of the Chinese Horseshoe Crab, Tachypleus tridentatus.

Chinese horseshoe crab, Tachypleus tridentatus, is an ancient marine arthropod with a long evolutionary history. As a kind of living fossil species, the pathogen defenses of horseshoe crabs entirely depend on the innate immune system. Although, there are abundant immune molecules found in the horseshoe crab hemolymph, the biological mechanisms underlying their abilities of distinguishing and defending against invading microbes are still unclear. In this study, we used high-throughput sequencing at mRNA and protein levels and bioinformatics analysis methods to systematically analyze the innate immune response to Gram-negative bacteria in hemolymph of Chinese horseshoe crab. These results showed that many genes in the complement and coagulation cascades, Toll, NF-κB, C-type lectin receptor, JAK-STAT, and MAPK signaling pathways, and antimicrobial substances were activated at 12 and 24 h post-infection, suggesting that Gram-negative bacteria could activate the hemolymph coagulation cascade and antibacterial substances release via the above pathways. In addition, we conjectured that Toll and NF-κB signaling pathway were most likely to participate in the immune response to Gram-negative bacteria in hemolymph of horseshoe crab through an integral signal cascade. These findings will provide a useful reference for exploring the ancient original innate immune mechanism.

[Modified reconstruction of the cistern magna for treatment of syringomyelia with Chiari malformation: clinical analysis of 35 cases].

OBJECTIVE: To explore the surgical approaches, microsurgical techniques and therapeutic effect of modified cistern magna reconstruction for treating of syringomyelia with Chiari malformations. METHODS: The clinical data of 35 patients with syringomyelia complicated by Chiari malformations were retrospectively reviewed, and the patients' chief complaints, presenting symptoms, neurological and radiographic findings, surgical approaches, outcomes, and complications were analyzed. RESULTS: The radiographs revealed type I Chiari in 18 and type II Chiari malformations in these patients. Surgical treatment resulted in symptomatic improvements in 29 patients, and 6 patients showed no obvious changes in the symptoms after the surgery; 3 patients received subarachnoid shunting for syringomyelia. During the follow-up for a mean of 2 years, 32 patients showed obvious clinical improvement, and magnetic resonance imaging demonstrated complete spontaneous resolution of syringobulbia in 25 patients. CONCLUSION: Modified cistern magna reconstruction relieves brainstem compression and restores the pulsatile flow of the cerebrospinal fluid at the cervicomedullary junction. Cerebellar tonsil reduction is performed chiefly by electric coagulation and cauterization combined with subpial resection, and the integrity of the pia mater should be maintained as much as possible to avoid potential adhesion and recurrence. The median foramens and Luschka of the fourth ventricle have to be opened to recover normal CSF circulation. Arachnoidal suspension and placement of a patulous dural graft are also important. Modified reconstruction of the cistern magna can be a good option for treatment of syringomyelia complicated by Chiari malformations.

[Whole-range encirclement method versus conventional method for microvascular decompression for treatment of hemifacial spasm].

OBJECTIVE: To compare the efficacy and micromanipulation techniques of microvascular decompression with whole-range encirclement method and the conventional method in 65 cases of hemifacial spasm. METHODS: The data of 65 surgically managed cases of hemifacial spasm were retrospectively analyzed for intraoperative findings, surgical techniques, and the patients' outcomes. Microvascular decompression with the conventional approach was performed in 30 patients (group A), and whole-range encircling method was used in the other 35 patients (group B). The patients were also divided into group C (below 40 years, n=27) and group D (above 40 years, n=38) according to the onset age of the symptom. RESULTS: In these patients, 4 patterns of facial nerve compression were identified: simple contact, contact and indentation, adhesion and encasement, and unidentified offending vessels. The offending vessels included the arteries, veins, and vascular loops. In most patients in group C, the arachnoid membrane around the facial nerve thickened and encircled the offending ve;ssel; in group D, the characteristic changes of the vasculature occurred in the offending artery, resulting in its displacement. In groups A and B, the overall efficacy rate was 80% and 97.1%, with recurrence rates of 13.3% and 2.9%, respectively. The major permanent complications in group A included hearing impairment (10.0%) and ataxia (6.7%), whose incidences in group B were 2.9% and 2.9%, respectively. CONCLUSION: Microvascular decompression with whole-range encircling method is a safe approach associated with high cure rate, in which careful avoidance of injuries to the cranial nerves and the penetrating vessels from the root entry/exit zone and the pons ensure good outcome and minimize the likeliness of recurrence and complications.