NT5C2 expression in children with acute leukemia and its clinical significance / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the expression level and analyze the clinical significance of NT5C2, which is an nucleoside analogues metabolism related gene, in children with acute leukemia (AL).</p><p><b>METHODS</b>Real-time PCR and immunohistochemistry were presented to detect the level of NT5C2 mRNA and its protein product cN- Ⅱ in bone marrow samples of 63 patients initially diagnosed with AL, 15 patients who achieved complete remission, 7 patients who relapsed and 16 non- hematologic malignancie controls. The expression of NT5C2 mRNA in different groups of AL and its relevance with clinical indicators were analyzed.</p><p><b>RESULTS</b>①The expression of NT5C2 mRNA in newly diagnosed B-ALL, TALL, AML and controls were 1.16 (0.89-2.25, 0.96 (0.74-1.25, 1.66 (0.84-3.15) and 0.88 (0.61-1.21), respectively. NT5C2 mRNA expression in AML (P<0.01) and B-ALL (P<0.05) cases were higher than that in controls; NT5C2 mRNA expression in T- ALL and in controls showed no significant difference (P>0.05). Changes of NT5C2 mRNA level were observed between preliminary diagnosis and complete remission in 15 patients. NT5C2 mRNA levels were significantly decreased in complete remission stage than that in newly diagnosis AL (P<0.01). NT5C2 mRNA levels of relapsed-refractory group were higher than that of complete remission group and controls (P<0.01). ② Immunohistochemical staining results revealed that NT5C2 protein levels were consistent with the trend of mRNA levels. ③NT5C2 mRNA levels in AML (r=0.434) and T-ALL (r=0.389) were positively correlated with risk classification (P<0.05). ④ During chemotherapy of patients with AML, the NR rate of bone marrow in NT5C2 high expression group was higher than that of low expression group after 9 days induction chemotherapy (35.2% vs 0) and before consolidation therapy (25.0% vs 0); The positive rate of minimal-residual disease (36.4% vs 14.3%) and relapse rate of AL (38.5% vs 28.6%) were increased in NT5C2 high expressed patients than that in low expressed patients, but all the differences were insignificant (P>0.05).</p><p><b>CONCLUSION</b>High expression of NT5C2 was found to be a related risk factor of AL children with unfavourable prognosis. NT5C2 promises a new target for guiding individualized chemotherapy and evaluating the prognosis of childhood acute leukemia and monitoring recurrence.</p>

Overexpression of CD73 in epithelial ovarian carcinoma is associated with better prognosis, lower stage, better differentiation and lower regulatory T cell infiltration / 부인종양

OBJECTIVE: The purpose of the current study was to evaluate survival outcome according to the expression status of CD73 in patients with epithelial ovarian cancer. METHODS: A total of 167 patients with epithelial ovarian cancer were enrolled in the current study. For each patient, a retrospective review of medical records was conducted. Immunohistochemical staining for CD73, CD8, FoxP3, and CD68 was performed using tissue microarray made with paraffin embedded tissue block. RESULTS: Among the enrolled patients, 29.9% of patients (n=50) showed negative expression for CD73, whereas 70.1% of patients (n=117) showed positive expression for CD73. The CD73 positive group showed better prognosis compared to the CD73 negative group (5-year overall survival of CD73 positive group, 73.0%; that of CD73 negative group, 50.1%; p=0.023). CD73 was more frequently expressed in mucinous adenocarcinoma and clear cell carcinoma compared to serous or endometrioid adenocarcinoma. In addition, CD73 overexpressions were more frequently detected in patients with known good prognostic factors, i.e., low stage, well/moderate differentiation, negative peritoneal cytology, no lymphovascular involvement, and no macroscopic residual tumor after debulking surgery. There was significantly more infiltration of regulatory T cells in the CD73 negative group compared to the CD73 positive group. CONCLUSION: Good prognosis in patients with overexpression of CD73 may be due to that overexpression of CD73 was more frequently observed in epithelial ovarian cancer patients with known good prognostic factors. Therefore, this result means that favorable differentiation and stage have more influence on survival outcome than adverse effect of CD73 per se.

Overexpression of CD73 in epithelial ovarian carcinoma is associated with better prognosis, lower stage, better differentiation and lower regulatory T cell infiltration / 부인종양

OBJECTIVE: The purpose of the current study was to evaluate survival outcome according to the expression status of CD73 in patients with epithelial ovarian cancer. METHODS: A total of 167 patients with epithelial ovarian cancer were enrolled in the current study. For each patient, a retrospective review of medical records was conducted. Immunohistochemical staining for CD73, CD8, FoxP3, and CD68 was performed using tissue microarray made with paraffin embedded tissue block. RESULTS: Among the enrolled patients, 29.9% of patients (n=50) showed negative expression for CD73, whereas 70.1% of patients (n=117) showed positive expression for CD73. The CD73 positive group showed better prognosis compared to the CD73 negative group (5-year overall survival of CD73 positive group, 73.0%; that of CD73 negative group, 50.1%; p=0.023). CD73 was more frequently expressed in mucinous adenocarcinoma and clear cell carcinoma compared to serous or endometrioid adenocarcinoma. In addition, CD73 overexpressions were more frequently detected in patients with known good prognostic factors, i.e., low stage, well/moderate differentiation, negative peritoneal cytology, no lymphovascular involvement, and no macroscopic residual tumor after debulking surgery. There was significantly more infiltration of regulatory T cells in the CD73 negative group compared to the CD73 positive group. CONCLUSION: Good prognosis in patients with overexpression of CD73 may be due to that overexpression of CD73 was more frequently observed in epithelial ovarian cancer patients with known good prognostic factors. Therefore, this result means that favorable differentiation and stage have more influence on survival outcome than adverse effect of CD73 per se.

Genetic detection and enzymatic analyses in α-thalassaemia patients with pyrimidine 5' nucleotidase deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the clinical significance of genetic detection and changes of red cell enzyme activities of pyrimidine 5' nucleotidase (P5'N), pyruvate kinase (PK) and glucose-6-phosphate dehydrogenase (G-6-PD) in patients with α-thalassaemia (α-thal).</p><p><b>METHODS</b>Three α-thal patients were further processed to gene detection by PCR-trans-dot blot and gap-PCR, and red cell enzymes activities by absorbance at 260 and 280 nm (A) for P5'N and fluorescence spot test for PK and G-6-PD.</p><p><b>RESULTS</b>Red cells in 3 α-thal cases were microcytic hypochromic with obvious augmented target cells and basophilic stippling erythrocytes. Two patients had anemia, splenomegaly, hyperbilirubinemia and augmented LDH. HbH was positively identified by hemoglobin electrophoresis and hemoglobin cellulose acetate membrane electrophoresis; the other patient had no such abnormalities. Genotypes of 3 patients were of (-α(3.7)/--(SEA)), (αα(QS)/--(SEA))and (--(SEA)), respectively. The activity of P5'N (but not for PK and G-6-PD) in red cell reduced.</p><p><b>CONCLUSIONS</b>This is the first documented α-thal with P5'N deficiency. Genetic detection might be clinical significant for the diagnosis and pedigree screening of α-thal.</p>

Rapid Isolation of Adipose Tissue-Derived Stem Cells by the Storage of Lipoaspirates

PURPOSE: This study examined a rapid isolation method decreasing the time and cost of the clinical application of adipose tissue-derived stem cells (ASCs). MATERIALS AND METHODS: Aliquots (10 g) of the lipoaspirates were stored at 4degrees C without supplying oxygen or nutrients. At the indicated time points, the yield of mononuclear cells was evaluated and the stem cell population was counted by colony forming unit-fibroblast assays. Cell surface markers, stem cell-related transcription factors, and differentiation potentials of ASCs were analyzed. RESULTS: When the lipoaspirates were stored at 4degrees C, the total yield of mononuclear cells decreased, but the stem cell population was enriched. These ASCs expressed CD44, CD73, CD90, CD105, and HLA-ABC but not CD14, CD31, CD34, CD45, CD117, CD133, and HLA-DR. The number of ASCs increased 1x1014 fold for 120 days. ASCs differentiated into osteoblasts, adipocytes, muscle cells, or neuronal cells. CONCLUSION: ASCs isolated from lipoaspirates and stored for 24 hours at 4degrees C have similar properties to ASCs isolated from fresh lipoaspirates. Our results suggest that ASCs can be isolated with high frequency by optimal storage at 4degrees C for 24 hours, and those ASCs are highly proliferative and multipotent, similar to ASCs isolated from fresh lipoaspirates. These ASCs can be useful for clinical application because they are time- and cost-efficient, and these cells maintain their stemness for a long time, like ASCs isolated from fresh lipoaspirates.

Characteristics and clinical significance of CD73 expression in subtypes of leukemia / 中国实验血液学杂志

The study was purposed to investigate the expression of CD73 on bone marrow nucleated cells (BMMNC) in various leukemia subtypes and its relationship with cell differentiation of leukemia. Immunocytochemistry staining and Wright-Giemsa staining of BMMNC from 75 cases of leukemia, 11 cases of myelodysplastic syndrome (MDS), 13 cases of non-leukemic patients and 9 healthy adults were performed, and the CD73(+) ratio in BMMNC and its relationship with differentiation of leukemia cells were analyzed. The results showed that the ratios of CD73(+) in BMMNC of com-B ALL, pre-B ALL and PLL were significantly higher than those in B-CLL (p < 0.05). CD73(+) ratios in AML subtypes of M(1), M(2a), t (8; 21), t (15; 17), M(4) and M(5) were markedly higher than those in MDS respectively, but in M(6) and MDS were lower and had no statistical difference between them. CD73(+) ratios in T-ALL, B-CLL, M(6), MDS, non-leukemia patients and healthy adults were close to each other and all of them were lower than those in B-ALL and other AML subtypes. It is concluded that the expression of CD73 is associated with leukemia subtype, differentiation and development. The higher differentiation of leukemia cells, the lower of CD73 expression in myeloid and B lymphoid leukemia, but T-ALL does not meet this pattern.

Role of PKC in regulation of CD73 by lysophosphatidylcholine in human endothelial cells / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To discuss the effect of protein kinase C (PKC) on regulation of ecto-5'-nucleotidase activity by lysophosphatidylcholine(LPC) in human umbilical endothelial cells (HUVEC).</p><p><b>METHODS</b>Experiments were conducted in HUVEC grown on dishes which were divided into 4 groups (n=15): (1) Control group in which only eAMP (5 micromol/L) was added; (2) LPC group in which HUVEC were incubated with LPC (10 micromol/L) before eAMP was added; (3) Chelerythrine group in which cells were pre-incubated with the PKC inhibitor chelerythrine (100 micromol/L) before LPC and eAMP were added; (4) alpha, beta-Methyladenosine-5'-Diphosphate (AOPCP) group in which cells were incubated with AOPCP (10 micromol/L) before eAMP was added. Etheno-adenosine production was detected at 15th, 30th, 45th min with high performance liquid chromatography(HPLC) respectively.</p><p><b>RESULTS</b>Comparing to the control group LPC significantly increased etheno-adenosine production at three time points respectively (P < 0.05). Furthermore, PKC inhibitor chelerythrine abolished this effect of LPC and the ethenoadenosine production at three time points were at the same level of control group (P > 0.05). CD73 inhibitor AOPCP significantly decreased the etheno-adenosine production compared to the other three groups (P < 0.01).</p><p><b>CONCLUSION</b>Ecto-5'-nucleotidase can be modulated within minutes following exposure of HUVEC to LPC and this response may be mediated by PKC in HUVEC.</p>

Ultrastructural analysis of 5' nucleotides distribution in acute myeloid leukemia subtypes / 中国实验血液学杂志

5' nucleotides (5'NT), a purine degradative enzyme, is capable of hydrolyzing nucleotide and acting as a phosphotransferase simultaneously. It has critical role in maintaining nucleotide metabolism balance. The present study was aimed to investigate the expression of 5'NT in bone marrow granulocytes (BMGs) from patients with acute myeloid leukemia (AML) and healthy donors comparatively. The BMGs were isolated from bone marrow of 33 patients with AML and 6 healthy donors by using lymphocyte isolating solution. The reactivity of 5'NT was detected by electron microscope and cytochemistry of cytidine monophosphate (CMP). The positive BMG ratio and their index were calculated on the base of ultrastructural observation semiquantitatively. The results indicated that electron microscopy revealed plasma membrane reacting pattern of CMP. Most BMGs from normal donors were CMP negative or exhibited lower active degree. All cases of M(0), M(1), M(2) and t (8; 21) showed high positive percentages and high indexes of BMGs, but no statistic differences between them. APL of t (15; 17) shared lower percentages and indexes than other subtypes. There was no significant difference between APL and normal donors statistically. In conclusions, the results suggested the expression of 5'NT may be associated with BMG differentiation in AML, and APL of t (15; 17) may be a highly differentiated leukemia subtype.

Endothelial cells derived from mesenchymal stem cells harbor immunoregulatory effects / 中国实验血液学杂志

This study was purposed to investigate the immunoregulatory effect of endothelial cells derived from mesenchymal stem cells (MSC). The human MSC was induced to differentiate into endothelial cells for one week. The phenotypes were evaluated by flow cytometry, the cell morphologic feature was observed by invert phase-contrast microscope and analysis of capillary formation was performed by using the in vitro angiogenesis kit. The immunoregulatory effect was detected by lymphocyte transformation test. The result indicated that during the differentiation cells grew fast and there was no significant change in the phenotypes, i.e. CD73, CD105, HLA-ABC were positive and CD34, CD80, CD86, HLA-DR, CD31 were negative. Immunofluorescence analysis showed typical expression of the von Willebrand factor. Differentiated MSCs formed capillary-like structure. Endothelial cells derived from MSC also revealed immunosuppressive effect on T cell proliferation in a dose-dependent manner. It is concluded that endothelial cells derived from MSC also harbor immunoregulatory effect on T lymphocytes.

A modified method to isolate and identify the adult mesenchymal stem cells from human bone marrow / 中国实验血液学杂志

The study was aimed to establish a protocol of isolating and culturing adult mesenchymal stem cells (MSC) from human bone marrow aspirate and identify them by surface antigen analysis and committed differentiation in order to provide an experimental foundation for achieving a therapeutic benefit in applying MSC in hematopoietic stem cell transplantation. MSCs were obtained from fresh human bone marrow aspirate by gradient centrifugation with Percoll (1.073 g/ml) and anchoring culture in L-DMEM with 10% fetal bovine serum by a full medium exchange every 3 days. The MSC surface antigens, including CD34, CD45, CD73, CD105, CD166, were analyzed on FACScan flow cytometer. Under culture in conditioned medium for osteogenesis (the hormone cocktail containing 0.1 micromol/L dexamethasone, 10 mmol/L glycerol-2-phosphate and 50 micromol/L ascorbic acid) and adipogenesis (the cocktail containing 1 micromol/L dexamethasone, 5 mg/L insulin, 0.5 mmol/L 1-methyl-3-isobutylxanthine and 60 micromol/L indomethacin), MSCs committedly differentiated into osteoblasts and adipocytes. The differentiated mesenchymal stem cells were identified by morphological observation and immunohistochemical staining. The results showed that by gradient centrifugation and adhesion culture, MSCs could be isolated and culture-expanded from human bone marrow aspirate. These cells were uniformly negative for CD34, CD45 and positive for CD73, CD105 and CD166. The osteogenic differentiated cells were positive for alkaline phosphatase (ALP) and the adipogenic differentiated cells displayed accumulation of lipid vacuoles, as detected by oil red O. It is concluded that MSC can be isolated and expand-cultured from adult human bone marrow aspirate and committedly differentiate into osteoblasts and adipocytes. MSC primary identification can be accomplished by flow cytometry and induced differentiation. The set of methods in current experiment shows somewhat practical value for basic research and clinical application.

Comparative study on the activity of 5'-nucleotidase 5-nt and gamma glutamyl transferase [GGT] in some tissues of donkeys, calves and goats [the effect of freezing and thawing] [with one table and 2 figures]

5'-nucleotidase [5'-NT] and Gamma glutamyl transferase [GGT] activity was measured in the tissues of four 2-6 years old donkeys; four 6-9 month old castrated male goats and four 6-9 month old male calves. In donkeys the lung is the richest source of the enzyme 5'-NT, whereas in goats the liver contains a higher activity of the enzyme compared with other species. Generally the values of 5'-NT activities in tissues of calves and goats are higher than those of donkeys. GGT is mainly located in the kidneys, pancreas and liver of all the species studied. 20-25% loss in activity of GGT occurred after thawing and freezing of tissues for 2 weeks whereas more than 50% loss in activity of the enzyme occurred in four weeks period. The fall in the activity of 5'-NT in tissues was not consistent in all tissues during the first two weeks, but after four weeks period 50% loss of activity was observed

In vitro biological characteristics of mesenchymal stem cells from patients with myelodysplastic syndrome and their support to hematopoiesis / 中国实验血液学杂志

To study the biological characteristics of mesenchymal stem cells (MSC) from patients with myelodysplastic syndrome (MDS) and their supportive capacity for hematopoiesis in vitro, MSCs from bone marrow samples of MDS patients were isolated, cultured and expanded. Morphology, immunophenotype, osteoblasts differentiative and proliferative property of MSC and colony forming unit-fibroblast (CFU-F) were measured and analyzed. Mononuclear cells (MNC) of cord blood were plated onto a feeder layer formed by MSC of MDS patient, cells count and CFU-GM production were observed. The results showed that the culture-expanded cells from MDS patients presented a typical fibroblast-like morphology. Cells were positive for SH2 (CD105), SH3 (CD73), Thy-1 (CD90), but negative for CD34 and CD45. After induction, these cells could differentiate into osteoblasts. Their proliferative capacity and CFU-F number were similar to those of MSC from healthy donors. The total cell count and CFU-GM yield in supernatants after culture for 2 weeks were significantly lower than those of control in hematopoiesis supportive experiments in vitro (P < 0.05). It is concluded that the biological characteristics of MSC from bone marrow of MDS patients are not different from those of MSC isolated from bone marrow of normal donors, however, their capacity of hematopoiesis support in vitro are significantly weaker.

Withdrawal effect of codeine and phenobarbitone on the brain and cardiac function enzymes and glucose metabolism in adult albino rats

This study is to elucidate the withdrawal of codeine and phenobarbiton and their effects on some brain, cardiac activity and glucose-insulin-glucagone relations. This may help to clarify the side effect and metabolic changes which may occur as a result of drug administration. For this aim forty adult albino rats were randomly divided to 5 groups each of eight animals. First group was kept as control. Second and third group received codeine orally in therapeutic and double therapeutic dose. Forth and fifth group were given phenobarbiton intramuscular in therapeutic and double therapeutic dose. Drugs were administered day after day for four consecutive weeks. Alterations in serum Monoamine oxidase [MAO] activities, Cholinesterase [ChE] activities, whereas 5' nucleotidase [5'NT] and creatine kinase [CK] activity lactate dehydrogenase [LDH], Aspartat-aminotransferase [AST], glucose, insulin and glucagon were recorded. Such alterations were discussed in relation to doses and levels of drugs in urine of rats that actually stopped drug and exhibited that the analgesic effects symptoms of the drugs are expression of changes of functioning enzymes

Diagnostic value of 5' Nucleotidase on kala - Azar patients

5'-Nucleotidase activity was measured in the sera of [67] Kala-azar patients before treatment and at different stages of treatment with pentostam as well as in [30] age matcher normal children. The changes in 5'-NT isoenzyme profile were also followed among the above cases. A change of the activity of the enzyme with the progress of the disease was observed. Our result suggest also that there are changes in the 5'-NT isoenzyme profile with the severity of the disease

Influence of capparis spinosa and acacia arabica on certain biochemical haemolymph parameters of Biomphalaria alexandrina

This work investigated the molluscicidal potency of dried Capparis spinosa and Acacia arabica leaves on some selected biochemical parameters of Biomphalaria alexandrina, in order to render them, physiologically, unsuitable for S. mansoni infection or at least disturb the lifecycle of the parasite within its respective snail host. The effect of the two plants on lactate dehydrogenase [LDH], 5'-nucleotidase, acid phosphatase [AP], aspartate and alanine aminotransferases [AST and ALT], alkaline phosphatase [ALP] and glucose content were studied. This work was extended to evaluate the effect of these two plants on protein profile as well as total protein [TP] content of snail's in hemolymph after 24 hours and 1 week of snails plants feeding. The study revealed that both plants induced a marked alteration in all measured parameters, where LC50 of C. spinosa after feeding at one week showed the most potent effect

Sperm immobilization activity of Allium sativum L. and other plant extracts / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To identify possible spermicidal agents through screening a number of edible medicinal plants with antimicrobial activity.</p><p><b>METHODS</b>Initial screening was made on the basis of ram cauda epididymal sperm immobilization immediately after addition of extracts. The most potent extract was selected and was evaluated on both ram and human spermatozoa. To unravel its mode of action several sperm functional tests were carried out, namely viability of cells, hypo-osmotic swelling test for membrane integrity and assays of membrane-bound enzyme 5'-nucleotidase and acrosomal marker enzyme acrosin.</p><p><b>RESULTS</b>The crude aqueous extract of the bulb of Allium sativum L. showed the most promising results by instant immobilization of the ram epididymal sperm at 0.25 g/mL and human ejaculated sperm at 0.5 g/mL. Sperm immobilizing effects were irreversible and the factor of the extract responsible for immobilization was thermostable up to 90 deg. On boiling at 100 deg for 10 minutes, this activity was markedly reduced. Moreover, this extract was able to cause aggregation of ram sperms into small clusters after 30 minutes of incubation at 37 deg. However this property was not found in human spermatozoa. More than 50 % reduction in sperm viability and hypo-osmotic swelling occurred in treated sperm as compared with the controls, indicating the possibility of plasma membrane disintegration which was further supported by the significant reduction in the activity of membrane bound 5'-nucleotidase and acrosomal acrosin.</p><p><b>CONCLUSION</b>The crude aqueous extract of A. sativum bulb possesses spermicidal activity in vitro.</p>

Microsequencing, analysis of molecular weight and amino acid composition for pyrimidine 5'-nucleotidase I of human erythrocytes / 中国实验血液学杂志

To further explore the mechanism of congenital pyrimidine 5'-nuleotidase I (P5'N-I) deficiency, on the basis of purification of the protein, the molecular weight and amino acid composition were analysed by mass-spectrograph and amino-acid analyzer, microsequencing and bioinformation analysis of P5'N-I were performed after it was hydrolysed by trypsin. The results showed that three fractions were found in the purified P5'N-I and their molecular weights were 26,952.9, 55,476 and 110,938, respectively. The sequence from one of the peptide fragments was I-E-G-P-T-I-R-Q-I-E. The homologous sequence was not found after comparision with the ten-amino-acid sequence in GenBank by blast procedure. Amino acid analysis indicated that P5'N-I was composed of 18 amino acids at least, and 243 amino acid residues. In conclusion, the enzyme might be an allosteric enzyme, there might be homologous dimer or tetramer in physiological status of normal human erythrocyte, the microsequence could be designed as the probe for fishing the genes of interest. The composition of amino acid might be an important information in determination of its protein primary structure.

Expression of adenosine deaminase and 5'-nucleotidase in artificially induced deciduoma in rat and hamster.

Enzymes adenosine deaminase (ADA) and 5-nucleotidase (5-'NT) are known to play active role in tissue/cell proliferation and differentiation. To validate this the two enzymes were studied in artificially induced deciduoma of rat and hamster. The deciduoma was induced by traumatizing one of the uterine horns of progesterone primed animals. Non traumatized horn served as control. The animals were later maintained on progesterone, given alone (Gr.I) or conjointly with estrogen (Gr.II). The weight of each uterine horn was recorded to determine the formation of deciduoma. There was no marked difference between the weights of traumatized and control horn on day 2 post-traumatization (PT), but a progressive rise was noticed after this day in both species. The ADA activity however differed, day and species wise. While in the rats of Gr.I it was low in the traumatized horn on all the days, in the hamsters it was remarkably high from day 2 to 6 PT. In the rats of Gr.II also the activity though was low in the traumatized horn, but on day 2 and 4 only; on day 6 and 7 PT it increased markedly. In hamster, on the contrary, again the enzyme activity was remarkably high on all the three days. The 5'-NT activity, however, did not show any marked difference between the two horns under Gr.I and II in both species. It was rather high in the control horn of each group. The results suggest: (I) the progesterone alone though produces a significant rise in the uterine weight of traumatized horn in both species, the ADA activity increases only in hamster, (2) under the conjoint treatment also the enzyme activity remains high in hamster; and (3) the activity of enzyme 5'-NT does not alter during the deciduoma formation in both the species.