Research Progress on Species Identification of Sarcosaprophagous Flies

Abstract

Estimation of postmortem interval （PMI） has always been one of the difficult problems for forensic scientists. It is especially hard to estimate the PMI of highly decomposed corpses in the wild or in secluded houses with conventional methods. Therefore, application of insect evidence at the scene is usually required for estimation. Sarcosaprophagous flies of different species have totally different developmental rates. In actual cases, direct measurement of the body length of the larvae, calculation of accumulated temperature and succession stages without species identification, or calculation based on incorrect species identification would often lead to a large deviation between the calculated results and the real PMI. This mistake would also mislead the case investigation. Therefore, accurate species identification should be implemented before any PMI estimation of decomposed corpses with forensic entomological methods. This article reviews the general and ultramicroscopic species identification and molecular biological species identification methods of different stages of sarcosaprophagous flies, in order to provide new ideas and methods for related research and practice, and provide reference for the application and promotion of forensic entomology in the front line of public security.

[The application of neuroimaging reconstruction technique in evaluating the relationship between skeletal musculature tumors and nerves nearby]

Objective: To analyze the relationship between tumors of the musculoskeletal system and adjacent nerves by reconstructing images of peripheral nerves, and explore its value in surgical treatment. Methods: From May 2016 to April 2019, a total of 27 patients were collected in Department of Imaging,Shougang Hospital, who were with skeletal muscle system tumors, including 15 primary soft tissue tumors, 9 primary bone tumors, 3 metastatic tumors, all of them were closely related to nerves. There were 17 males and 10 females, aged 13-67 years, with an average age of 34 years. Before the operation, CT volume scanning was performed, and curved planar reconstruction (CPR) was used to reconstruct the peripheral nerves. All patients were operated within 2 weeks after the examination. According to the image characteristics before the operation, the nerve invasion was judged. The sensitivity, characteristic, positive predictive value and negative predictive value of the tumor invasion (compression) nerve were calculated according to the intraoperative findings as the gold standard. Result: Of the 27 cases, 25 cases (25/27, 92.6%) could show the relationship between the tumors and the adjacent nerves at the same level, and 22 cases (22/25, 88.0%) had the same preoperative image judgments as the intraoperative findings. In the reconstructed images, the peripheral nerve was a continuous strip-like structure on the same level with the tumor. The invaded nerve became thicker and the edge was blurred. Enhanced scan showed enhancement. The sensitivity, specificity, positive predictive value and negative predictive value of neuroimaging reconstruction were 100.0%, 89.5%, 75.0% and 100.0% respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the nerve compression were 92.3%, 100.0%, 100.0% and 80.0% respectively. Conclusions: Neurological reconstructed images can help clinicians evaluate the relationship between lesions and adjacent nerves quickly and intuitively. They can guide the selection of surgical methods, reduce the risk of intraoperative nerve injury, and have high sensitivity and specificity for nerves invasion.

Analysis of 28S rRNA and COⅠ Gene Sequence of Nine Necrophagous Calliphorid Flies from Luoyang

Abstract

Objective To assess the feasibility of using 28S ribosomal RNA （28S rRNA） and mitochondrial cytochrome c oxidase subunit Ⅰ （COⅠ） gene sequences of nine necrophagous Calliphorid flies for the identification of common necrophagous Calliphorid flies, and to provide technical support for postmortem interval （PMI） estimation. Methods Twenty-three Calliphorid flies were collected and identified morphologically, and DNA were extracted from legs. The gene fragments of 28S rRNA and COⅠ were amplified and sequenced, then the sequence alignment was performed with BLAST. The composition of obtained sequences was analyzed and evolutionary divergence rate between species and intraspecies were established. The phylogeny tree was constructed with neighbor-joining method. Results The 23 necrophagous Calliphorid flies were identified to 9 species of 5 genera. The 715 bp from 28S rRNA and 637 bp from COⅠ gene were obtained and the online BLAST result showed more than 99% of similarity. The phylogeny tree showed that the necrophagous flies could cluster well into 9 groups, which was consistent with morphological identification results. The intraspecific difference in 28S rRNA was 0 and the interspecific difference was 0.001-0.033. The intraspecific difference in COⅠ was 0-0.008 and the interspecific difference was 0.006-0.101. Conclusion Combined use of 28S rRNA and COⅠ gene sequence fragments can effectively identify the nine Calliphorid flies in this study. However, for closely related blowfly species, more genetic markers should be explored and used in combination in future.

[Molecular Identification of Sarcosaphagous Flies in Luoyang Based on 28S rRNA Gene Sequence]

OBJECTIVES

To detect 715 bp sequence of 28S rRNA in sarcosaphagous flies, and to identify their common species for solving the problem of morphological identification, as well as providing technical support for postmortem interval （PMI） estimation.

METHODS

Twenty-nine common sarcosaphagous flies were collected in Luoyang and classified by morphological characteristics. The DNA was extracted from the fly's legs by Chelex-100 method and then the fragments of 28S rRNA were amplified and sequenced. The results were compared with twenty-eight corresponding fly species of GenBank and EMBL databases. All the sequences were analyzed by MEGA7.0 software, and sequence alignment was performed by the searching in BLAST. The nucleotide composition was analysed, and the intraspecific and interspecific genetic distance and phylogenetic tree were established.

RESULTS

Twenty-nine sarcosaphagous flies were classified into 6 species of 5 genera, 3 families by morphological characteristics. In the obtained 715 bp sequence of 28S rRNA, the comparison result of online BLAST showed that the similarity was 100%. Five species were well clustered by a phylogenetic tree. Between different groups, the interspecific and intraspecific differences ranged from 0.007 to 0.045 and 0 to 0.001, respectively.

CONCLUSIONS

The 28S rRNA target gene sequences shows a good identification capability, which can be a new genetic marker for the identification of sarcosaphagous flies.

[DNA Extraction from Old Bones by AutoMate Express™ System]

OBJECTIVES

To establish a method for extracting DNA from old bones by AutoMate Express™ system.

METHODS

Bones were grinded into powder by freeze-mill. After extraction by AutoMate Express™, DNA were amplified and genotyped by Identifiler®Plus and MinFiler™ kits.

RESULTS

DNA were extracted from 10 old bone samples, which kept in different environments with the postmortem interval from 10 to 20 years, in 3 hours by AutoMate Express™ system. Complete STR typing results were obtained from 8 samples.

CONCLUSIONS

AutoMate Express™ system can quickly and efficiently extract DNA from old bones, which can be applied in forensic practice.

Serum concentrations of resistin and adiponectin and their relationship to insulin resistance in subjects with impaired glucose tolerance

OBJECTIVES

This study measured the serum concentrations of resistin and adiponectin in Chinese subjects with impaired glucose tolerance (IGT) and investigated their association with insulin resistance, metabolic parameters and circulating inflammatory markers.

METHODS

A total of 124 subjects participated in the study (44 with IGT and 80 with normal glucose tolerance [NGT]). Fasting serum concentrations of lipids, glucose, insulin and adipocytokines (resistin, adiponectin, leptin, tumour necrosis factor-α [TNF-α], interleukin-6 and C-reactive protein) were measured.

RESULTS

Serum resistin concentrations were similar in the IGT and NGT groups but were significantly higher in overweight/ obese IGT subjects than in those of normal weight. Serum adiponectin concentrations were significantly lower in the IGT group than in the NGT group. In the IGT group, resistin was positively correlated with age, body mass index and TNF-α, and adiponectin was correlated positively with high-density lipoprotein cholesterol and negatively with TNF-α and waist/hip ratio.

CONCLUSIONS

Circulating resistin is unlikely to be a major mediator of glucose tolerance in humans but it may have an inflammatory role in IGT. The data support the theory that circulating adiponectin has an anti-inflammatory and anti-insulin resistance function.

A new experimental system for study on adaptive mutations

A super-repressed mutant of purR (purR(S)), which encodes a repressor protein controlling expression of purine biosynthetic genes inSalmonella typhimurium, grew very slowly on NCE medium with 10 mug/mL Ade and lactose as sole carbon source (cannot form colonies). However, a phenomenon of late-arising mutations was observed when purR(S) mutants were spread on NCE+lactose plates and subjected to a prolonged non-lethal selection. The reconstruction experiments of revertants showed that the late-arising "lac(+)" mutants are not slow growing mutants. Statistical analysis indicated that the distribution of late-arising mutants is Poisson distribution, showing that reversion occurred after plating. The result of co-transductional analysis preliminarily showed that late-arising mutation occurred at selected genepurR or 16 bp PUR box,cis element of structural genepurD. The above results suggest that the phenomenon of late-arising mutation observed by our system is a result of adaptive mutations which are different from random mutations. This is the first time to extend target genes at which adaptive mutations could occur from structural genes involved in carbon metabolism and amino acid biosynthesis totrans regulatory gene coding repressor protein. Our results have provided not only a new proof for generality of adaptive mutations but also a new system for study on adaptive mutations.

Real-time detection of dental calculus by blue-LED-induced fluorescence spectroscopy

Successful periodontal therapy requires sensitive techniques to discriminate dental calculus from healthy teeth. The aim of the present study was to develop a fluorescence-based procedure to enable real-time detection and quantification of dental calculus. Thirty human teeth--15 teeth with sub- and supragingival calculus and 15 healthy teeth--covered with a layer of physiological saline solution or blood were illuminated by a focused blue LED light source of 405 nm. Autofluorescence spectra recorded along a randomly selected line stretching over the crown-neck-root area of each tooth were utilized to evaluate a so called calculus parameter R, which was selected to define a relationship between the integrated intensities specific for healthy teeth and for calculus in the 477-497 nm (S(A)) and 628-685 nm (S(B)) wavelength regions, respectively. Statistical analysis was performed and a cut-off threshold of R=0.2 was found to distinguish dental calculus from healthy teeth with 100% sensitivity and specificity under various experimental conditions. The results of the spectral evaluation were confirmed by clinical and histological findings. Automated real-time detection and diagnostics for clinical use were implemented by a corresponding software program written in Visual Basic language. The method enables cost-effective and reliable calculus detection, and can be further developed for imaging applications.

Specific heat of single-crystal PrMnO3

The specific heat of single-crystal PrMnO₃ was investigated from 2 to 200 K under different magnetic fields up to 8 T. A Schottky-like anomaly observed at low temperature was gradually shifted to higher temperatures by magnetic fields. The first four singlets of the Pr^3+ 3H₄ ground multiplet in PrMnO₃ are given for the first time by fitting the specific heat of Pr³⁺ ions below 40 K under zero field. By analysing the field dependence of the first singlet of Pr³⁺ ions, the Pr-Mn exchange field is found to be negligible, which is consistent with the magnetic anisotropy of Pr³⁺ ions revealed in the magnetic measurement. At T_N, the cooperative antiferromagnetic ordering of Mn³⁺ spins shows up as λ-shaped anomaly, which is lowered and broadened in magnetic fields. The magnetic entropy near T_N is estimated by subtracting the contributions to specific heat from Pr³⁺ ions and lattice vibrations. It was found that the fraction of entropy above T_N in the total entropy increases with the fields due to the enhancement of spin fluctuations by magnetic field.

Ecology. Giant pandas in a changing landscape

The giant panda has been restricted to several disjunct montane forest populations, and habitat loss and fragmentation are the primary threats to its survival. For pandas to survive, conservation efforts must focus on larger landscapes rather than individual nature reserves. China recently initiated several policies, including the Natural Forest Conservation Program and Grain-to-Green Policy, which provide a historic opportunity to integrate panda conservation into national policies. Simultaneously, China is promoting the Western China Development Program, which calls for substantial infrastructure and hydropower development and economic investments. Integrating panda conservation into these development policies will be a critical challenge.

[Research and application of drug controlled release technique in tissue engineering]

OBJECTIVE

To investigate protection of biological activity and controlled release of growth factor by means of drug controlled release technique in tissue engineering.

METHODS

Using drug controlled release technique that to embed or microcapsulate the biological drug with biodegradable polymer.

RESULTS

The aliphatic polylactone could be used as drug carrier for each drug including the biological matter. And the release behavior of the drug could be controlled by adjusting the molecular structure of the carrier and the controlled release method. The successful example, that to realize regeneration of rat's sciatic nerve with 5, 10, 15 and 20 mm of gap by using polylactide as nerve guide and the embedding growth factor, had been obtained.

CONCLUSION

It is possible to realize protection of biological activity and sustained release of growth factor by using aliphatic polylactone as drug carrier.

[Differential regulation of sodium pump alpha-subunit isoform gene by ouabain and digoxin in myocardium of rats]

OBJECTIVE

To compare the effects of ouabain and digoxin on both the systolic blood pressure (SBP) and sodium pump alpha-subunit expression in myocardium of rats.

METHODS

Normal Sprague-Dawley (SD) rats were injected with ouabain, digoxin or normal saline (NS) everyday and indirect SBP was recorded once a week. Six weeks later, all the rats were killed and sodium pump alpha1-, alpha2-, and alpha3-subunit were detected in the left ventricular myocardium with RT-PCR method and immunohistochemical assay at mRNA and protein levels.

RESULTS

At the end of six weeks SBP of rats infused with ouabain increased significantly (132.6 +/- 9.0 vs 115.7 +/- 8.2 mm Hg, P < 0.01), while no difference of SBP was found between digoxin group and NS group. The effects of ouabain and digoxin on sodium pump alpha-subunit isoform expression in myocardium were also different: both ouabain and digoxin stimulated expression of alpha3-isoform whereas alpha2-isoform unchanged at both mRNA and protein levels. alpha1-isoform was decreased in ouabain group and alpha1-isoform unchanged in digoxin group at both mRNA and protein levels.

CONCLUSION

It is suggested that both ouabain and digoxin could regulate sodium pump alpha-subunit isoform expression, which might be related to the physiological roles of endogenous ouabain and might be responsible for the difference between the pharmacological and toxicological effects of ouabain and digoxin, including their effects on blood pressure.

Simulation of biomass gasification with a hybrid neural network model

Gasification of several types of biomass has been conducted in a fluidized bed gasifier at atmospheric pressure with steam as the fluidizing medium. In order to obtain the gasification profiles for each type of biomass, an artificial neural network model has been developed to simulate this gasification processes. Model-predicted gas production rates in this biomass gasification processes were consistent with the experimental data. Therefore, the gasification profiles generated by neural networks are considered to have properly reflected the real gasification process of a biomass. Gasification profiles identified by neural network suggest that gasification behavior of arboreal types of biomass is significantly different from that of herbaceous ones.

[Regulating effects of transforming growth factor-beta (TGF-beta) on gene expression of collagen type II in human intervertebral discs]

OBJECTIVE

To assess the regulating effects of TGF-beta on gene expression of collagen type II in the human intervertebral discs.

METHODS

In situ hybridization was used to investigate the effect of TGF-beta1 on collagen mRNA in confluent primary and passaged monolayer cell cultures of annulus fibrosus (AF) as well as nucleus pulposus (NP). The mean photodensitometry of cell smears as semi-quantitative analysis was evaluated by VIDAS software.

RESULTS

In primary cultures, 1 ng/ml and 10 ng/ml TGF-beta1 inhibited the collagen type II mRNA levels by 74.6% and 60.2% respectively in AF; they also inhibited the mRNA levels by 69.6% and 55.5% respectively in NP. In passaged cultures in which the notochordal cells and chondrocytes were in dedifferentiation status, 1 ng/ml and 10 ng/ml TGF-beta1 increased the collagen type II mRNA levels by 151% and 166% respectively in AF and also increased the mRNA levels by 145% and 198% respectively in NP.

CONCLUSIONS

The regulation effect of TGF-beta on collagen type II gene expression is dependent on whether the cells are fully differentiated or undergoing phenotype loss, and TGF-beta may play an important role in the repair process during early disc degeneration, especially in nucleus pulposus.

[Influence of isoflurane and sevoflurane on metabolism of oxygen free radicals in cardiac valve replacement]

To investigate effects of isoflurane and sevoflurane on the levels of lipid peroxides (LPO) in plasma and superoxide dismutase (SOD) in red blood cells during myocardial ischemia/reperfusion, and to study myocardial protection of these two volatile anesthetcs, 30 patients undergoing cardiac valve replacement were randomly divided into isoflurane (Group I), sevoflurane (Group S), and controlled group (Group C). Patients of Group I were anesthetized with isoflurane mainly, Group S with sevoflurane, and Group C with fentanyl. LPO and SOD levels were measured at five points before and during the operation. The results were as follows: SOD levels in all groups did not change significantly. LPO levels in Group C increased during the operation, while in other two groups didn't. Rates of automatical rebeating of hearts in Group C were lower than that of hearts in other two groups. It is suggested that isoflurane and sevoflurane can inhibit increasing of LPO levels to attenuate myocardial ischemia/reperfusion injuries mediated by oxygen free radicals during open-heart surgery.

[Ultra trace determination of platinum, palladium, gold and rhodium in minerals]

Our work studied the minerals dissolved in aqua regia. The trace Pt(II), Pd(II) Au (III) and Rh(I) complexes were loaded by the mixed carbon powder which carried diphenyl thiourea when aqua regia or hydrochloric acid media as well as stannous chloride were present. We added some carbon powder in ashen loader and determined the elements with atomic emission spectrometry. The determination sensitivity counted with 10 grams of samples is 1 x 10(-9). The RSD for 0.05 x 10(-6) standard Pt, Pd, Au and Rh solutions are 6.0%, 5.1%, 8.5% and 11.4%, respectively. The method is simple and operation is easy. The results satisfy our requirement.

[Detection of CD59(-) blood cells in patients with aplastic anemia]

OBJECTIVE

To detect paroxysmal nocturnal hemoglobinuria (PNH) clone in aplastic anemia (AA) patients.

METHODS

Flow cytometric technique along with antibodies against CD59 was used to estimate the amount of GPI-P deficient cells, characteristic of PNH abnormalities.

RESULTS

Among 23 cases of AA studied, 13 possessed no excessive percentage of CD59(-) cells in peripheral PMNs and RBCs. Eight of these 13 cases underwent bone marrow examination, and no increase of CD59(-) mononuclear cell (MNC) was found either. Three other AA patients had slightly increased amount (> 5%) of CD59(-) cells in both peripheral blood and bone marrow. In seven cases, percentages of CD59(-) cells were normal in peripheral RBCs and PMNs but increased in bone marrow MNCs.

CONCLUSION

Measurement of CD59(-) cells in periperal blood and bone marrow by flow cytometry may serve as the best way of detecting PNH clone in AA, and thus could be used for the early diagnosis of AA-PNH syndrome.

Alterations of cardiac and lymphocyte beta- adrenoceptors in rat with chronic heart failure

The alterations of cardiac and lymphocyte beta-adrenoceptors were observed in the rats with chronic heart failure produced by constriction of both abdominal aorta and renal artery. The results showed that beta(1)-adrenoceptor density and mRNA levels were increased, whereas these levels remained unchanged for beta(2). The concentrationcontractile response curve for isoproterenol was shifted m the right in cardiac atrium, whereas the concentration-CAMP accumulation response curve for isoproterenol in myocardium was not changed. The number of beta-adrenoceptom in blood lymphocyte was markedly reduced. Thus in the heart-failure rats the density of cardiac beta-adrenoceptor was increased accompanying reduced beta-adrenoceptormediated positive inotropic response, suggesting a post adenylate cyclase dysfunction or impaired contractile components. In contrast, the alteration of beta-adrenoceptor in lymphocyte is consistent with the reduced beta-adrenoceptor-mediated inotropic response in heart.

High expression of synthetic human interferon-gamma cDNA in E. coli

Human interferon-gamma (IFN-gamma) cDNA was synthesized, and it makes the usage of favorable codons in E. coli. The authors got 9 different expression plasmids which contain the synthetic IFN-gamma-cDNA and have different spaces between SD sequence and ATG. The free energies G0f298 in the formation of stable secondary structure in the translation initiation region (TIR) are different in various expression plasmids. One of them, pLY4-gamma 5, can highly yield INF-gamma which will be about 60%-80% of the total bacterial proteins, such a high expression was hardly noted in literature. The reasons of high expression in this work are optimal spaces between SD and ATC, favorable delta G0f298, favourable condons usage for E. coli.

[Post-operative radiotherapy of glioma in the cerebral hemisphere in adult--a retrospective study of 326 cases]

Three hundred twenty-six cases of adult patients with glioma in the cerebral hemisphere treated by post-operative radiotherapy at the General Hospital, Tianjin Medical University from 1976 through 1990 were reviewed. The 1-, 3-, 5- and 10-year survival rate was 76.8%, 62%, 55.7% and 42.1%, respectively in low grade gliomas and the 1-, 3-, and 5-year survival rate was 44.3%, 35% and 27.1% respectively in high grade gliomas. In this study, patients' age, performance status before radiotherapy and histopathologic type of the tumor are important factors influencing the treatment outcome. There is no correlation between radiation dose and survival rate. Since 1988, combined photon and electron beams from linear accelerator have been used with a total dose of 65-70Gy to the target area.

Aging of nucleolar organizer region in rat basal forebrain neurons related to learning and memory

The nucleolar organizer of rat basal forebrain neurons was studied with histochemical and morphometrical techniques, in order to analyze quantitatively the morphological correlate of activity as it changes during learning and aging of the brain. The learning abilities of adult (2 months) and senile (30 months) rats were tested with a conditioned response learning paradigm. Four groups of rats were defined: one group consisted of untrained adults, a second group consisted of trained adults, and the senile rats were subdivided into one group, which was able to learn and another group which was not able to perform the test. Frozen sections through the basal nucleus were silver stained to visualize the nucleolar organizer and the area of its profile was measured. The data showed that the nucleolar organizer in both the trained adult and the senile rats who were able to learn, was much larger than that in the untrained adults and the senile rats who were not able to learn. In the latter groups the nucleolar organizers were of equal size. An additional finding was, that the senile rats who could not be trained, showed a lower neuronal density in the basal nucleus compared with that of the trainable senile and adult rats. The changes in the size of the nucleolar organizer are interpreted as a morphological sign of learning-induced increases in transcription and synthesis of ribosomal RNA.

[Protective effect of panaxatriols on function of reproductive endocrine axis in radiation-injured rats]

After whole body irradiation with X-ray 5 Gy (radiation condition: 0.31 Gy.min-1, 200 kV, 10 mA, 0.5 mm Cu and 1.0 mm Al), the male rats were given ip panaxatriols 5 mg.d-1 24 h before and after irradiation for 14 d. The results showed that hypothalamic leu-enkephalin (165 +/- 12 vs 131 +/- 14 pg.mg-1), pituitary beta-endorphin (2.3 +/- 0.5 vs 1.6 +/- 0.3 ng.mg-1) contents, and serum testosterone (1.66 +/- 0.15 vs 0.82 +/- 0.23 ng.ml-1) level were decreased, while serum FSH (1.34 +/- 0.10 vs 1.99 +/- 0.10 ng.ml-1) level increased in irradiation group vs normal control. These indices approached to control levels in irradiation + panaxatriols group. These suggest that panaxatriols have protective effects on reproductive endocrine axis and promote their recovering course from the radiation injuries.