[Characteristics of Pollution and Microbial Community Structure in the Antimony Mining Area of Longnan, Gansu Province].

Antimony （Sb） is a major pollutant that poses a serious threat to the environment in the mining and processing of nonferrous metals, coexisting with sulfide and oxide of arsenic （As）. Microorganisms play an important role in the migration, transformation, and repair of metals in soil. The ecological effects of bioavailable Sb and As on the microbial community in antimony mining areas（mining and smelting areas）are still poorly understood. The Wenzel method and high-throughput 16S rDNA amplicon were used to characterize soil pollution characteristics in different functional areas, and the relationship between the bacterial community and bioavailable concentrations have been investigated comprehensively. The results showed that： Chemical speciation of Sb and As were amorphous, and poorly crystalline hydrous oxides of Fe and Al （F3） > well-crystallized hydrous oxides of Fe and Al （F4） > residual phases （F5） > specifically adsorbed （F2） > non-specifically adsorbed （F1）. According to the estimation of the potential ecological risk index （RI） and geo-accumulation index （Igeo）, the Sb pollution degree was： smelting area > mining area > contrast area, in which the smelting area showed serious pollution, and the mining area showed moderate to severe pollution. The As pollution degree was： mining area > smelting area > contrast area, in which the mining area and smelting area showed moderate to severe pollution. High-throughput 16S rDNA amplicon showed that Proteobacteria was the most abundant phylum in mining and smelting areas； Kaistobacter, Pseudomonas, Sphingomonas, and Lysobacter were the most abundant microbial genera； Geobacter and Luteolibacter had a high LDA score in mining areas； and Thiobacillus had a high LDA score in antimony-contaminated areas. Spearman correlation analysis, variation partitioning analysis （VPA）, and random forest （RF） analysis showed that Sb, As, bioavailable antimony [Sb （Bio）], and bioavailable arsenic [As （Bio）]were the main factors affecting the microbial community structure in different functional areas of antimony ore. Redundancy analysis （RDA） indicated that Sb and its bioavailable concentrations showed uniformly negative associations with the relative abundance of bacteria Nitrospirae and showed a significant positive correlation with Thiobacillus （P<0.05）. The in-depth research on the ecological effects of bioavailable Sb and As on the bacterial community provides references and new perspectives for environmental monitoring and management.

Quarantine Disinfestation of Papaya Mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae) Using Gamma and X-rays Irradiation.

Paracoccus marginatus is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade should undergo phytosanitary treatment, and irradiation is recommended as a viable alternative to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-day-old eggs and gravid females of P. marginatus using the X-ray radiation doses of 15-105 Gy with an interval of 15 Gy. Radiotolerance was compared using ANOVA, fiducial overlapping and lethal dose ratio (LDR) test, resulting in no significant difference among treatments, except for the overall mortality and LDR at LD90 (a dose causing 90% mortality at 95% confidence level). The estimated dose for LD99.9968 was 176.5-185.2 Gy, which was validated in the confirmatory tests. No nymphs emerged from a total of 60,386 gravid females exposed to a gamma radiation dose range of 146.8-185.0 Gy in the confirmatory tests. The largest dose in confirmatory tests should be the minimum threshold for phytosanitary treatment, consequently, a minimum dose of 185 Gy is recommended for the phytosanitary irradiation treatment of papaya mealybug-infested commodities, ensuring a treatment efficacy of ≥99.9950% at 95% confidence level.

Phytosanitary irradiation treatment of the aerial root mealybug, Pseudococcus baliteus (Hemiptera: Pseudococcidae).

The aerial root mealybug, Pseudococcus baliteus Lit (Hemiptera: Pseudococcidae), is an important invasive and quarantine pest that poses a potential threat to fruits, vegetables, and ornamental plants. As a result, phytosanitary treatments are necessary to ensure the commodities of international trade are free from these pests. To determine the minimum absorbed dose required for phytosanitary irradiation (PI) application, irradiation dose-response and large-scale confirmatory tests were conducted. Eggs that were 2, 4, and 6 days old and late gravid females (containing 0-day-old eggs) of P. baliteus were X-ray irradiated with doses of 10, 20, 40, 60, 80, 100, and 120 Gray (Gy). The efficacy of preventing egg-hatching (mortality) was compared using two-way ANOVA, 95% confidence interval overlapping and lethal dose ratio test in probit analysis. The radiotolerance sequence of mealybugs egg was found to be 0 < 2 ≈ 4 < 6-day-old eggs, and their estimated LD99.9968 values with 95% confidence interval were 132.0 (118.9-149.5), 137.6 (125.2-153.7), 145.5 (134.5-159.1), and 157.4 (144.6-173.6) Gy, respectively. Subsequently, target doses of 135 and 145 Gy were used in the confirmatory gamma radiation treatments. No F1 generation neonates developed from a total of 47,316 late females irradiated at the measured dose of 107.7-182.5 Gy, resulting in the treatment efficiency of 99.9937% at the 95% confidence level. Therefore, the highest dose of 183 Gy measured in the confirmatory tests is recommended as the minimum absorbed dose in PI treatment of P. baliteus for establishing national and international standards.

Combination of Modified Atmosphere and Irradiation for the Phytosanitary Disinfestation of Trogoderma granarium Everts (Coleoptera: Dermestidae).

The khapra beetle, Trogoderma granarium Everts, is defined as one of the most important quarantine pests globally, and fumigation with methyl bromide, an ozone-depleting substance, is a common phytosanitary measure currently used. The modified atmosphere (MA), irradiation, and their combination treatments of T. granarium larvae and adults were performed at room temperature (24-26 ℃) to develop an ecofriendly phytosanitary disinfestation measure and to shorten the exposure time and overcome treatment disadvantages of irradiation. Late-stage larvae are determined as the most tolerant stage resulted in large LT99.9968 values of 32.6 (29.2-37.5) and 38.0 (35.1-41.7) days treated under 1% and 2% O2 (with N2 balance) atmosphere, respectively. Ionizing radiation was used to enhance the effect of MA and the mortality was highly significantly affected by all the interaction effects, indicating that the synergistic effects present in all the combined treatments. The synergistic ratios, which is defined as the estimated lethal time for MA treatment (LD90, LD99, and LD99.9968), divided by that of combined treatment, were between 1.47 and 2.47. In the confirmatory tests, no individuals recovered from a sum of 111,366 late-stage larvae treated under 1% O2 atmosphere for 14- or 15-d after 200 Gy irradiation, which resulted in validating the probit estimations and achieving an efficacy of 99.9973% mortality at 95% confidence level. Therefore, these treatment schedules are recommended to disinfest T. granarium infecting commodities for phytosanitary purposes under the warehouse, MA packaging, or in combination with international transportation by train or sea container.

A genetic link between CXCR5 and IL2RA gene polymorphisms and susceptibility to multiple sclerosis.

OBJECTIVES: Multiple sclerosis (MS) is a T-cell-mediated disease of the central nervous system that develops in individuals possessing a complex susceptibility trait. We explored relationship between gene polymorphisms in MS. METHODS: To identify the associations of CXCR5 and IL2RA gene polymorphisms with susceptibility to MS, we recruited 263 MS patients from the Han nationality and 138 from the Hui nationality as MS group and 284 healthy volunteers from the Han nationality and 156 from the Hui nationality as controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was employed to test gene polymorphisms of IL2RA (rs2104286 and rs12722489). Sequenom MassARRAY system was applied to analyze genotyping of CXCR5 (rs3922). RESULTS: The genotypes and allele frequency distributions at the loci of IL2RA rs2104286 and rs12722489 showed significant differences between the MS and control groups. The gene polymorphisms at the loci of IL2RA rs2104286 and rs12722489 may increase the onset risk of MS. IL2RA-rs2104286 showed a positive relationship with CXCR5-rs3922. The same relationship was also observed between IL2RA-rs12722489 and CXCR5-rs3922. The genotypes and allele frequencies of loci of rs2104286 and rs12722489 were significantly different in MS clinical subtypes and severity (EDSS score). Additionally, CAC and TGC haplotype at rs3922-rs12722489-rs2104286 may reduce the risk of MS, while CGT and TGT haplotypes increase the risk. CONCLUSION: The gene polymorphisms at the loci of IL2RA rs2104286 and rs12722489 are closely associated with susceptibility to MS in the Han and Hui nationalities.