Application of multiplex PCR approaches for shark molecular identification: feasibility and applications for fisheries management and conservation in the Eastern Tropical Pacific

Here we describe the application of new and existing multiplex PCR methodologies for shark species molecular identification. Four multiplex systems (group ID, thresher sharks, hammerhead sharks and miscellaneous shark) were employed with primers previously described and some designed in this study, which allow for species identification after running PCR products through an agarose gel. This system was implemented for samples (bodies and fins) collected from unidentified sharks landed in the port of Buenaventura and from confiscated tissues obtained from illegal fishing around the Malpelo Island Marine Protected Area, Pacific Coast of Colombia. This method has allowed reliable identification, to date, of 407 samples to the genus and/or species levels, most of them (380) identified as the pelagic thresher shark (Alopias pelagicus). Another seven samples were identified as scalloped hammerhead sharks (Sphyrna lewini). This is an easy-to-implement and reliable identification method that could even be used locally to monitor shark captures in the main fishing ports of developed and developing countries.     

Movements of brown smoothhounds, <Emphasis Type="Italic">Mustelus henlei</Emphasis>, in Tomales Bay,California

Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and five female brown smoothhounds and tracked during the period of 29 June to 15 July 2004. Coarse-scale tracking consisted of locating all tagged individuals multiple times during a single session, while fine-scale tracking consisted of following a single individual continuously during a session. Coarse-scale tracking suggested movement toward the inner bay with incoming and high tides and toward the outer bay with outgoing and low tides (P = 0.01), whereas the diel cycle had no apparent effect on their movement directions. Mean shark movement rate was 0.09 m s⁻¹ (range: 0.01–0.34 m s⁻¹), with diel and tidal cycles both having significant effects on their rates of movement (P = 0.02 and P < 0.01), respectively. We tracked two female sharks on a fine scale over three tracking sessions in July 2004. Both individuals exhibited higher rates of movement during the night compared to the day (P < 0.01). While one shark’s rate of movement was not significantly affected by tidal stage, the other’s was (P < 0.001).     

Discovery of a multispecies shark aggregation and parturition area in the Ba Estuary,Fiji Islands

Population declines in shark species have been reported on local and global scales, with overfishing, habitat destruction and climate change posing severe threats. The lack of species‐specific baseline data on ecology and distribution of many sharks, however, makes conservation measures challenging. Here, we present a fisheries‐independent shark survey from the Fiji Islands, where scientific knowledge on locally occurring elasmobranchs is largely still lacking despite the location's role as a shark hotspot in the Pacific. Juvenile shark abundance in the fishing grounds of the Ba Estuary (north‐western Viti Levu) was assessed with a gillnet‐ and longline‐based survey from December 2015 to April 2016. A total of 103 juvenile sharks identified as blacktip Carcharhinus limbatus (n = 57), scalloped hammerhead Sphyrna lewini (n = 35), and great hammerhead Sphyrna mokarran (n = 11) sharks were captured, tagged, and released. The condition of umbilical scars (68% open or semihealed), mean sizes of individuals (±SD) (C. limbatus: 66.5 ± 3.8 cm, S. lewini: 51.8 ± 4.8 cm, S. mokarran 77.4 ± 2.8 cm), and the presence of these species over recent years (based on fishermen interviews), suggest that the Ba Estuary area is a critical habitat for multiple species that are classified as “Near Threatened” or “Endangered.” Specifically, the area likely acts as a parturition ground over the studied period, and potentially as a subsequent nursery area. We identified subareas of high abundance and found that temperature, salinity and depth acted as small‐scale environmental drivers of shark abundance. The data suggests a tendency for species‐specific spatial use, both horizontally (i.e., between sampling areas) and vertically (i.e., across the water column). These results enhance the understanding of shark ecology in Fiji and provide a scientific basis for the implementation of local conservation strategies that contribute to the protection of these threatened species.     

Low Birth Weight and Normal Birth Weight Newborns of Kolkata, India: Comparison of Some Maternal Risk Factors

This study compared several maternal risk factors of low birth weight (LBW) between 204 normal birth weight (NBW) and 133 LBW newborns from Kolkata, India. Based on their birth weight (BW), newborns were classified as LBW (BW < 2.5 kg) and NBW (BW ≥ 2.5 kg). Results revealed that means for maternal age (MA, p < 0.05), gestational age (GA, p < 0.01), hemoglobin (Hb) concentration (p < 0.05), and per capita daily income (PCDI, p < 0.05) were significantly higher among mothers of NBW. Correlation analyses revealed that MA (r = 0.119, p < 0.05), GA (r = 0.583, p < 0.01), PCDI (r = 0.118, p < 0.05), and Hb (r = 0.138, p < 0.05) were significantly positively correlated with BW; PCDI was also significantly positively correlated (r = 0.142, p < 0.01) with Hb. Stepwise regression analyses with BW as the dependent variable revealed that GA (t = 7.915, p < 0.001) and Hb (t = 2.057, p < 0.05) were the most important predictive variables. The effect of Hb, independent of GA, was statistically significant (change in F = 4.231, p < 0.05). Because GA is not modifiable in pregnant women, there is a need to increase Hb levels among pregnant mothers. Most importantly, appropriately targeted preventive strategies, including iron supplementation, need to be implemented for health promotion.     

Vulnerability to longline fisheries of three hammerhead shark Sphyrna species in the south‐western and equatorial Atlantic Ocean

Catch and effort data from 29 418 longline sets from Brazilian tuna longline vessels operating in the south‐western and equatorial Atlantic Ocean between 2004 and 2011 were analysed to investigate the distribution, catch rate and size of three species of hammerhead sharks (Sphyrna lewini, Sphyrna mokarran and Sphyrna zygaena). During that period, 6172 hammerhead sharks were caught. Among the elasmobranchs, the highest percentage of hammerhead sharks were caught in 2007, when they accounted for 3·90% of the group, while the lowest value of 0·40% was recorded in 2010. In general, the spatial distribution of the mean catch per unit effort (CPUE) by years and quarters showed a trend of higher catches near the equatorial region and in southern Brazil. The nominal mean CPUE was 0·12 Sphyrna spp. 1000⁻¹ hooks, with the highest value being recorded in 2007 (0·30 Sphyrna spp. 1000⁻¹ hooks). The standardized yearly CPUE estimated by a generalized linear model assuming a zero inflated negative binomial (ZINB) distribution were not much different from nominal values. Of the 205 sexed specimens, 117 were females and 88 were males, resulting in a sex ratio with a predominance of females (1·30:1·00), although not statistically significant. The total length of females ranged from 1200 to 2800 mm and of males from 1100 to 3100 mm. Juvenile hammerhead sharks represented 82 and 54% of the sexed female and male specimens, respectively.     

Performance Traits and Metabolic Responses in Goats (<Emphasis Type="Italic">Capra hircus)</Emphasis> Supplemented with Inorganic Trivalent Chromium

The effects of supplemental chromium (Cr) as chromic chloride hexahydrate in incremental dose levels (0, 0.5, 1.0, and 1.5 mg/day for 240 days) on metabolism of nutrients and trace elements were determined in dwarf Bengal goats (Capra hircus, castrated males, average age 3 months, n = 24, initial mean body weight 6.4 ± 0.22 kg). Live weight increased linearly (p < 0.05) with the level of supplemental Cr. Organic matter and crude protein digestibility, intake of total digestible nutrients, and retention of N (g/g N intake) increased (p < 0.05) in a dose-dependent linear manner. Serum cholesterol and tryacylglycerol concentrations changed inversely with the dose of supplemental Cr (p < 0.01). Supplemental Cr positively influenced retention of copper and iron (p < 0.05) causing linear increase (p < 0.01) in their serum concentrations. It was concluded that Cr supplementation may improve utilization of nutrients including the trace elements and may also elicit a hypolidemic effect in goats. However, further study with regards to optimization of dose is warranted.     

Identification of young‐of‐the‐year great hammerhead shark Sphyrna mokarran in northern Florida and South Carolina

Two sharks, visually identified in the field as young‐of‐the‐year (YOY) scalloped hammerhead Sphyrna lewini, were identified as great hammerhead Sphyrna mokarran based on nuclear‐encoded single nucleotide polymorphisms (SNP) and sequences of mtDNA. Individuals were captured and released in Bulls Bay, SC, and Saint Joseph Bay, FL, in 2013 and 2014, respectively. These findings indicate S. mokarran may be pupping in or around these areas and highlight new regions that may be a productive focus for future research on early life history of S. mokarran.     

Trace Elements Analysis of Urine and Hair in Tuberculous Pleurisy

In this study, copper, zinc, magnesium, manganese, selenium, and iron of urine and hair were measured in the patients with tuberculous (TB) pleurisy (n = 24) and in the control group (n = 20). Selenium, magnesium, and zinc of hair were found to be significantly lower in TB pleurisy cases than those in the control group (p < 0.05, p < 0.001, and p < 0.01, respectively). On the contrary, selenium and magnesium of urine were found to be significantly elevated in TB pleurisy cases than those in the control group (p < 0.05 and p < 0.001, respectively). There was no significant difference in the value of manganese and iron between TB pleurisy and the control group (p > 0.05). Copper level were significantly increased in hair and decreased in urine of the patients (p < 0.01). The occurrence of these abnormalities constitutes new information regarding trace elements in TB pleurisy patients. These results may provide an additional disease correlate for assessing TB pleurisy risk.     

Iodine Deficiency Among Hypothyroid Patients Living in Jeddah

The objective was to determine the prevalence of iodine deficiency among hypothyroid patients and the effect of dietary goitrogens on indices of iodine and thyroid status. This is a case-control study of 106 subjects who were recruited from King Abdulaziz University Hospital, Jeddah. Blood and urine were collected for serum thyroid hormones, thyroid autoantibodies, thyroglobulin (Tg) and urinary iodine concentration (UIC). Dietary iodine and goitrogenic food intake were assessed by questionnaire. Using World Health Organization (WHO) cutoff values for UIC, both controls and cases were iodine deficient (85% and 83%, respectively). Furthermore, dietary iodine was deficient in 23% of controls and 36% of cases. In cases, there was a positive association between UIC levels and serum thyroid stimulating hormone (r = 0.405, p < 0.01) and a negative association with serum fT₄ (r = −0.358, p < 0.01). Serum Tg antibody titers were also positively associated with dietary iodine (r = 0.328, p < 0.05). Patients with elevated serum autoantibodies had lower UIC and dietary iodine than those with normal serum autoantibodies. UIC was associated with dietary goitrogens including turnip (r = 0.280, p < 0.05) and pine (r = 0.289, p < 0.05) among cases. Iodine deficiency is common and the consumption of dietary goitrogens is high among euthyroid and hypothyroid subjects living in Jeddah.     

Relationship Between Serum Calcium and Magnesium Concentrations and Metabolic Syndrome Diagnostic Components in Middle-Aged Korean Men

It is thought that calcium and magnesium may be related to metabolic disorders such as obesity and metabolic syndrome; however, to date, there have been few studies investigating the association between serum calcium and magnesium levels and metabolic syndrome in middle-aged male adults. We aimed to investigate the association between serum calcium and magnesium levels and metabolic syndrome in Korean middle-aged male adults. Study subjects included 213 men aged 30∼60 years. MetS risk score is determined by adding the number of risk factors, waist circumference, triacylglyceride (TG), HDL cholesterol, glucose, and blood pressure (BP). The study population was divided into three groups according to the MetS risk score: group I (MetS risk score ≤1; n = 106), group II (MetS risk score = 2; n = 51), and group III (MetS risk score ≥3; n = 56). The serum Ca, according to increase of MetS risk score, was significantly higher (p < 0.001), and there was no significant difference in serum Mg concentration among the three groups. Subjects with high TG and high BP had higher serum calcium levels than those without such abnormalities. Subjects with higher glucose had lower serum magnesium levels than those without such abnormality. The correlation analysis indicated that the serum Ca had positive correlations with the MetS risk score (r = 0.1769, p < 0.01), serum TG (r = 0.2516, p < 0.001), and DBP (r = 0.2246, p < 0.01). The correlation analysis indicated that the serum Mg had an inverse relationship with serum glucose (r = −0.2404, p < 0.001). In conclusion, serum Ca had positive association with TG and BP, while serum Mg had negative association with serum glucose after adjusting age and BMI among the middle-aged Korean male adults.     

Comparison of Hypoglycemic Activity of Trace Elements Absorbed in Fermented Mushroom of <Emphasis Type="Italic">Coprinus comatus</Emphasis>

The effect of fermented mushroom of Coprinus comatus rich in trace elements, including vanadium, chromium, zinc, magnesium, copper, iron, and nickel, on glycemic metabolism was studied in this paper. Alloxan-induced hyperglycemic mice were used in the study. The blood glucose, glycohemoglobin, and glycogen synthesis of the mice were analyzed, respectively. At the same time, the gluconeogenesis of the normal mice was also determined. After the mice were administered (ig) with C. comatus rich in vanadium (CCRV), the blood glucose and the glycohemoglobin of alloxan-induced hyperglycemic mice decreased (p < 0.05, p < 0.01), glycogen synthesis of alloxan-induced hyperglycemic mice elevated (p < 0.01), the gluconeogenesis of the normal mice was inhibited (p < 0.01), and the sugar tolerance of the normal mice was improved. However, the same result did not occur in other groups. Vanadium at lower doses in combination with C. comatus induced significant effect on glycemic metabolism in mice.     

Hypoglycemic Activity of <Emphasis Type="Italic">Grifola frondosa</Emphasis> Rich in Vanadium

The hypoglycemic activity of fermented mushroom of Grifola frondosa rich in vanadium (GFRV) was studied in this paper. Alloxan- and adrenalin-induced hyperglycemic mice were used in the study. The blood glucose and the HbA1c of the mice were analyzed respectively. After the mice were administered (ig) with GFRV, the blood glucose and the HbA1c of alloxan-induced hyperglycemic mice decreased (p < 0.05, p < 0.01) and ascension of blood glucose induced by adrenalin was inhibited (p < 0.01). Also, the bodyweight of the alloxan-induced hyperglycemic mice was increased gradually. In the fermented mushroom of G. frondosa, vanadium at lower doses in combination with G. frondosa induced significant decreases of the blood glucose and HbA1c levels in hyperglycemic mice.     

The biology and conservation status of the large hammerhead shark complex: the great,scalloped, and smooth hammerheads

Hammerhead sharks are among the most intriguing yet imperiled groups of large sharks globally. Until recently, our understanding of their biology, movements, diet, and life histories was challenged by a lack of studies. In recent years there has been a surge of published studies on this group of sharks, incorporating new information on age and growth, behavior, and the threats they face. Here we summarize and compare what is known on the biology and conservation of the three largest species of hammerhead sharks: the great hammerhead (Sphyrna mokarran), the scalloped hammerhead (Sphyrna lewini), and the smooth hammerhead (Sphyrna zygaena). We chose these species since they are the most well-studied of the hammerheads, and also because they are commonly captured in target and non-target fisheries worldwide. Thus, we also discuss population trends and the vulnerabilities of each species, and make recommendations for future studies on these fascinating and complex elasmobranch fishes.     

Influence of Therapy with Metformin on the Concentration of Certain Divalent Cations in Patients with Non-insulin-Dependent Diabetes Mellitus

Research was performed on a group of 30 patients with non-insulin-dependent diabetes mellitus (NIDDM), who never received antidiabetic medication before, and on a group of 17 healthy adults. The patients were administered treatment with metformin, 1,000 mg/day. Plasmatic and urinary concentration of magnesium have been measured, copper and zinc along with the concentrations of glucose, HDL, LDL, cholesterol, tryglicerides, HbA1c, and total erythrocyte magnesium, in advance and after 3 months of treatment. Data showed significant differences in the NIDDM group vs the control group: for plasma magnesium—1.95 ± 0.19 vs 2.20 ± 0.18 mg/dl, p < 0.001; urine magnesium—237.28 ± 34.51 vs 126.25 ± 38.22 mg/24 h, p < 0.001; erythrocyte magnesium—5.09 ± 0.63 vs 6.38 ± 0.75 mg/dl, p < 0.001; plasma zinc—67.56 ± 6.21 vs 98.41 ± 20.47 μg/dl, p < 0.001; urine zinc—1,347.54 ± 158.24 vs 851.65 ± 209.75 μg/24 h, p < 0.001; plasma copper—111.91 ± 20.98 vs 96.33 ± 8.56 μg/dl, p < 0.001; and urine copper—51.70 ± 23.79 vs 36.00 ± 11.70 μg/24 h, p < 0.05. Treatment with metformin for 3 months modified significant erythrocyte magnesium—5.75 ± 0.61 vs 5.09 ± 0.63 mg/dl, p < 0.001 and urine magnesium—198.27 ± 27.07 vs 237.28 ± 34.51 mg/24 h, p < 0.001, whereas it did not modify significant the plasmatic and urinary concentration of the other cations. The erythrocyte magnesium concentration was inversely correlated with HbA1c (r = −0.438, p = 0.015). The plasma level of copper was positively correlated with HbA1c (r = 0.517, p < 0.003), tryglicerides (r = 0.534, p < 0.003), and cholesterol (r = 0.440, p < 0.05), and the plasma level of zinc was inversely correlated with glycemia (r = −0.399, p = 0.029). Our data show a significant action of metformin therapy, by increasing the total intraerythrocyte magnesium concentration and decreasing the urinary magnesium elimination, positively correlated with the decrease of glycemia and HbA1c in NIDDM patients.     

Trichuris Burdens in Zoo-Housed Colobus guereza

Trichuris spp. infect the majority of captive primate species along with an estimated 1049 million people worldwide, making it an important zoonosis [Stephenson, L. S., Holland, C. V., & Cooper, E. S. Parasitology, 121(Suppl.), S73–S95, 2000]. We investigated the efficacy of methods used to evaluate the prevalence of Trichuris spp. in 2 groups (n = 12) of socially housed Abyssinian colobus (Colobus guereza kikuyensis) at Paignton Zoo Environmental Park and the factors that may affect density. We collected individual and group fecal samples over 6 mo and estimated burden (egg counts/g of feces) of Trichuris spp. via the McMaster technique. Shedding was significantly higher in the afternoon than in the morning (matched-pairs t-test: t _[5] = −4.46, p < 0.01) and in dominant adult male colobus (Spearman rank: r _[5] = −0.94, p < 0.01; age: r _[5] = 0.89, p < 0.05). Parasitological studies of zoo-housed primates can be a useful tool to explore factors that may affect burdens of Trichuris spp. in them.     

Prediction of the heterosis of <Emphasis Type="Italic">Laminaria</Emphasis> hybrids with the genetic distance between their parental gametophyte clones

Eighteen microsatellite markers were used to determine the genetic distances between the parental gametophyte clones of 14 Laminaria hybrids, which were then used to establish a linear relationship with the heterosis (hybrid vigor) of economic traits including yield, mean blade try weight, mean blade fresh weight, blade length, blade width and mean blade thickness using regression analysis. Significant regression was found between the genetic distance (x) and the heterosis (y) of yield (y = 115.10x − 77.97, r = 0.8151, p = 0.00038), mean blade dry weight (y = 115.23x  −77.97, r = 0.8154, p = 0.00038), mean blade fresh weight (y = 100.08x − 57.85, r = 0.7306, p = 0.0030) and blade length (y = 204.11x − 46.77, r = 0.6963, p = 0.00566). The prediction of the heterosis of Laminaria hybrids with the genetic distance between parental gametophyte clones will facilitate the selection of elite Laminaria hybrids by avoiding the time-consuming and labor-intensive trait evaluation of a large number of hybridization combinations.     

SHBG,plasma, and urinary androgens in weight lifters after a strength training

Previous studies with different results have suggested that total and bioavailable testosterone levels are modified by physical exercise. Such changes may be related to modifications in cortisol levels and could be reflected in some urine androgens. To determine how weight lifting training may affect serum and urinary androgens, we measured total serum testosterone (T), cortisol, sex hormone binding globulin (SHBG) and urinary testosterone, epitestosterone, androsterone, and etiocholanolone, in a group of 19 elite weight lifters after 20 weeks of training. SHBG increased (from 27.5 ± 9.5 to 34.7 ± 8.1 nM, p < 0.05) whereas T/SHBG decreased significantly (from 1.10 ± 0.4 to 0.85 ± 0.3, p < 0.05). Serum total testosterone and cortisol did not change significantly. In urine, androsterone and etiocholanolone decreased significantly, whereas testosterone and epitestosterone remained unchanged. Changes in T/SHBG were related positively with changes in urinary androgens (r = 0.680, p < 0.01), and changes in SHBG were negatively related with changes in urinary androgens (r = −0.578, p < 0.01). These results suggest that intense physical activity may have an influence on the elimination of androgenic hormones due mainly to changes in their transporting protein SHBG.     

Protective Effects of Selenium and Vitamin E Combination on Experimental Colitis in Blood Plasma and Colon of Rats

Ulcerative colitis increases oxidative damage accompanied by production of free oxygen radicals. Selenium (Se) and vitamin E are two natural antioxidants. The present study was undertaken to investigate the possible protective role of Se and vitamin E combination in experimental colitis induced by acetic acid (AA) in rats. This study was carried out on three groups, namely the first (control), the second (experimental colitis group, 2 ml 5% acetic acid), and the third groups (2 ml 5% acetic acid, vitamin E (100 mg/kg body weight (bw)) plus Se (0.2 mg/kg bw)). The activities of catalase (CAT), prolidase (PRS), myeloperoxidase (MPO), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), total thiol (T-SH) were determined in plasma and colon samples. Macroscopic and microscopic damages in colon were increased by AA treatment (p < 0.01 and p < 0.01, respectively), whereas they were decreased by selenium and vitamin E treatment (p < 0.05 and p < 0.01, respectively). The activities of CAT and PRS in the plasma and colon were significantly affected (p < 0.05 and p < 0.01) by treatment of AA, Se, and vitamin E. MPO activity in colon was increased (p < 0.01) by AA treatment and decreased (p < 0.05) by Se and vitamin E administration. The values of TOS and OSI in plasma were increased (p < 0.5) by AA. The TAC and T-SH in colon were decreased (p < 0.05) by AA and increased (p < 0.05) by Se and vitamin E. Based upon these results, Se and vitamin E may play an important role in preventive indication of the oxidative damage associated by acetic acid caused inflammation.     

Stomach content analysis of juvenile, scalloped hammerhead shark Sphyrna lewini captured off the coast of Mazatlán, Mexico

We quantified the diet of juvenile, scalloped hammerhead shark Sphyrna lewini in the area off Mazatlan, Sinaloa, Mexico, to understand their feeding ecology this shark. The prey species of Sphyrna lewini were identified and quantified from stomach content analysis. In addition, we determined the variations between genders. During two fishing seasons (2000–2001 and 2001–2002), we analyzed 232 stomachs, of which 85% contained food. The trophic spectrum was composed of three species of cephalopods, six of crustaceans and 19 species of fish from mainly pelagic and benthic habitats. According to the Index of Relative Importance (%IRI), the cephalopod Loliolopsis diomedeae with IRI = 18%, fish of the family Carangidae IRI = 25% and family Synodontidae IRI = 19% constituted the main prey in general. The trophic niche width was <0.4, which indicated that S. lewini juveniles in this area feed on a wide range of prey items, though they showed a preference for a few prey items.     

Comparison of metabolite levels in callus of <Emphasis Type="Italic">Tecoma stans</Emphasis> (L.) Juss. ex Kunth. cultured in photoperiod and darkness

Tecoma stans is a tropical plant from the Americas. Antioxidant activity and both phenolic compound and flavonoid total content were determined for callus tissue of T. stans cultured in either a set photoperiod or in darkness. Callus lines from three explant types (hypocotyls, stem, and leaf) were established on B5 culture medium supplemented with 0.5 μM 2,4-D and 5.0 μM kinetin. While leaf-derived callus grew slower under a 16-h photoperiod (specific growth rate, μ = 0.179 d⁻¹, t _D = 3.9 d) than in darkness (μ = 0.236 d⁻¹, t _D = 2.9 d), it accumulated the highest amount (p < 0.05) of both phenolics (86.6 ± 0.01 mg gallic acid equivalents/g) and flavonoids (339.6 ± 0.06 mg catechin equivalents/g). Similarly, antioxidant activity was significantly higher (p < 0.05) when callus was cultured in period light than when grown in extended darkness. Antioxidant activity measured with a 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS)-based assay was 350.5 ± 15.8 mmol Trolox/g extract for callus cultured under a defined photoperiod compared to 129.1 ± 7.5 mmol Trolox/g extract from callus cultured in darkness. Content of phenolic compounds and flavonoids was in agreement with a better antioxidant power (EC₅₀ = 450 μg extract/mg 1,1-diphenyl-2-picrylhydrazyl) and antiradical efficiency. Results of the present study show that calli of T. stans are a source of compounds with antioxidant activity that is favored by culture under a set photoperiod.