Impact de la varicocélectomie chez les patients ayant une azoospermie non obstructive ou une oligozoospermie sévère

Objective

To evaluate the changes induced by retroperitoneal varicocelectomy on infertile men with nonobstructive azoospermia or severe oligozoospermia.

Patients and methods

The records were retrospectively evaluated for 46 infertile men with severe oligozoospermia (group I) and 15 infertile men with non-obstructive azoospermia (group II). The parameters of sperm before and after surgery and unassisted pregnancy rate were comparatively analysed.

Results

In the severe oligozoospermia group, the mean age of patients was 35.5 ± 6.4 (23–47 years). The mean duration of infertility was 4.9 ± 3.4 years (1–13 years). Of these patients, 41(89.1%) had bilateral varicocele and five (10.9%) had unilateral left-side varicocele. The varicocele was classified as grade I in two cases (4.3%), grade II in 39 cases (84.7%) and grade III in five cases (10.9%). After surgery, the mean sperm count increased from 1.85 ± 1.4 to 8.3 ± 10.3 millions/ml and mean sperm normal motility from 43.3 ± 21.5 to 47.6 ± 29.2%. The mean sperm abnormal morphology decreased from 65.05 ± 21.6 to 50.08 ± 26.9%. After a mean follow-up of 26.2 ± 11.6 months, the unassisted pregnancy rate in this group was 26.1%. In the non-obstructive azoospermia group (N = 15), the mean age of patients was 40.8 ± 7.2 (27–47 years). The mean duration of infertility was 6 ± 3.1 years (3–15 years). After varicocelectomy, an induction of spermatogenesis was observed in three patients (20%) with presence of motile sperm in the ejaculate. In this group, only one of the 15 men achieved unassisted pregnancy.

Conclusion

Retroperitoneal varicocele repair resulted in spermatogenesis induction with presence of motile ejaculated spermatozoa for some men with non-obstructive azoospermia. It induced spermatogenesis and fertility enhancement in men with severe oligozoospermia. Varicocele repair should be considered in men with non-obstructive azoospermia or severe oligozoospermia.     

Predictors of the paroxysmal atrial fibrillation recurrence following cryoballoon-based pulmonary vein isolation: Assessment of left atrial volume,left atrial volume index,galectin-3 level and neutrophil-to-lymphocyte ratio

Background

Cryoballoon-based pulmonary vein isolation (PVI) is a treatment option for atrial fibrillation (AF). Left atrial volume (LAV) and left atrial volume index (LAVi) are important parameters for long term success of PVI. Galectin-3 (Gal-3) and neutrophil to lymphocyte ratio (N/L ratio) are biomarkers to demonstrate the cardiac fibrosis and remodelling.

Freezability and Fertility Results with Uncentrifuged Stallion Semen

The first (1 to 3) sperm-rich fractions of the ejaculate were collected from 4 stallions using an open-ended vagina. The volume of the collected fractions was 12 ± 8 ml with a density of 475 ± 200 million spermatozoa/ml. Before freezing, the semen was diluted with a skim-milk based extender 1:1 to 1: 8 (volume of semen: volume of extender), depending on the initial sperm concentration to achieve a final concentration of 100 million/ml. The total number of spermatozoa in an insemination dose ranged from 0.7 to 1 billion spermatozoa. Within 12 h after ovulation, 48 mares were inseminated in 70 cycles. The total single-cycle pregnancy rate at day 21 was 24%, but varied from 10% to 33% per cycle among the stallions.     

Decline in seminal quality in Indian men over the last 37 years

Background

Since the first report of a decline in semen quality in 1974, there have been several reports of similar declines across populations. Despite some scattered reports of declining semen quality in the Indian sub-continent, comprehensive studies analyzing semen quality over the last few decades have not been undertaken. We undertook the present study to investigate the temporal trend in semen parameters in Indian populations over a period of 37 years (1979–2016).

Methods

Publications providing semen analysis details for fertile and infertile men from the Indian sub-continent were collected by a thorough literature search. Semen quality data for 6466 normal fertile or presumptive normal men (from 119 studies/data sets) and 7020 infertile men (from 63 studies/data sets) published between 1979 and 2016 were retrieved. We undertook systematic review and quantitative analysis of mean sperm count, motility, normal morphology and other available parameters. Data were analyzed to estimate semen parameters reference values for Indian men and to assess temporal trends in infertile, fertile and all subjects.

Results

Seminal quality shows a decreasing temporal trend and the decrease is higher in infertile than fertile males. In pooled analysis for all individuals, significant (p?<?0.05 or?<?0.001) declines in sperm concentration and normal morphology are observed; however, isolated analysis for each group shows declines without statistical significance. The mean (± SD) semen volume, sperm concentration, total motility, rapid linear progressive motility, normal sperm morphology and sperm viability for Indian fertile men are 2.88?±?0.77 ml, 81.08?±?29.21 million/ml, 66.37?±?10.95%, 52.64?±?15.78%, 56.68?±?20.23% and 72.63?±?8.31%, respectively, whereas in infertile these are 3.07?±?1.27 ml, 37.94?±?26.41 million/ml, 40.22?±?13.76%, 26.79?±?15.47%, 36.41?±?21.66% and 55.25?±?11.99%, respectively. The mean seminal parameter values were significantly lower (p?<?0.001) in infertile as compared to fertile men, except semen volume.

Conclusions

Semen parameters in Indian men have declined with time and the deterioration is quantitatively higher in the infertile group. The study also provides reference values for semen parameters in Indian men.

     

Keynote Symposium

The developmental potency of pre-implant parthenogentic goat embryos were compared under two chemical activation protocols in three different culture media groups. The in vitro matured oocytes were chemically activated by two protocols viz. P1 (CB-CHX-6DMAP) and P2 (Ca-CHX-6DMAP). The activated oocytes under both the protocols were developed in three culture media, viz. modified synthetic oviductal fluid (mSOF), research vitro cleave medium (RVCL), and RVCL-Blast. While comparing the developmental potential of activated oocytes, it was observed that the oocytes activated under P2 protocol pooled over three culture media group producing significantly higher mean cleavage rate (43.2?±?0.9 vs 40.6?±?1.5), blastocyst development (16.4?±?1.1 vs 12.6?±?0.8), and blastomere count (120.7?±?4.7 vs 113.2?±?4.1) as compared to P1 protocol. The comparison of effect of culture media pooled over protocol groups revealed that the mean cleavage rate observed under RVCL-Blast (44.8?±?1.3) and RVCL (45.3?±?0.5) were significantly higher (P?≤?0.01) than mSOF (35.8?±?1.2). However, the mean blastocyst development observed under RVCL-Blast group (18.8?±?3.2) was significantly higher than RVCL (14.0?±?0.8) and mSOF (10.8?±?0.4). Similarly, the mean blastomere count under RVCL-Blast group (136.0?±?3.7) was significantly higher (P?≤?0.01) than RVCL (114.7?±?1.0) and mSOF (100.2?±?0.5) groups. The semiquantitative RT PCR analysis showed the expression of pro-apoptotic caspase 3 gene in P1 and anti-apoptotic Mcl-1 gene in P2. This study concludes that the activation protocol P2 and embryo cultured under RVCL-Blast group were optimum for chemical activation and culture medium, respectively.     

Effects of long-term microgravity exposure in space on circadian rhythms of heart rate variability

We evaluated their circadian rhythms using data from electrocardiographic records and examined the change in circadian period related to normal RR intervals for astronauts who completed a long-term (≥6-month) mission in space. The examinees were seven astronauts, five men and two women, from 2009 to 2010. Their mean?±?SD age was 52.0?±?4.2 years (47–59?yr). Each stayed in space for more than 160 days; their average length of stay was 172.6?±?14.6 days (163–199 days). We conducted a 24-h Holter electrocardiography before launch (Pre), at one month after launch (DF1), at two months after launch (DF2), at two weeks before return (DF3), and at three months after landing (Post), comparing each index of frequency-domain analysis and 24-h biological rhythms of the NN intervals (normal RR intervals). Results show that the mean period of Normal Sinus (NN) intervals was within 24?±?4?h at each examination. Inter-individual variability differed among the stages, being significantly smaller at DF3 (Pre versus DF1 versus DF3 versus Post?=?22.36?±?2.50 versus 25.46?±?4.37 versus 22.46?±?1.75 versus 26.16?±?7.18?h, p?<?0.0001). The HF component increased in 2 of 7 astronauts, whereas it decreased in 3 of 7 astronauts and 1 was remained almost unchanged at DF1. During DF3, about 6 months after their stay in space, the HF component of 5 of 7 astronauts recovered from the decrease after launch, with prominent improvement to over 20% in 3 astronauts. Although autonomic nervous functions and circadian rhythms were disturbed until one month had passed in space, well-scheduled sleep and wake rhythms and meal times served as synchronizers.     

In vitro fertilizing characteristics of bovine spermatozoa with multiple nuclear vacuoles: A case study

A study was designed to determine the in vitro fertilizing characteristics of bovine semen with a high percentage of spermatozoa with multiple nuclear vacuoles. In Experiment 1, a total of 620 oocytes was divided into 2 groups and inseminated with spermatozoa from 1 of 2 different bulls at a concentration of 2 × 10⁵/ml. After Percoll washes, 73.5 ± 3.0% of spermatozoa from Bull A contained multiple nuclear vacuoles, while no sperm cells from Bull B contained vacuoles. After 19.5 ± 0.5 h of co-incubation of oocytes with spermatozoa, loosely attached sperm cells were removed by washing, and the oocytes were fixed between 2 poly-l-lysine coated glass slides. Mean (±SD) percentage of fertilization was significantly lower (P < 0.05) in Bull A (19.7 ± 7.0%) than in Bull B (67.6 ± 4.5%). In one-third of the oocytes fertilized by spermatozoa from Bull A, sperm head decondensation was incomplete and normal male pronucleus formation did not occur. All oocytes fertilized by Bull B had normally decondensed sperm heads. Although fewer (P < 0.05) spermatozoa from Bull A were bound to the zona pellucida than from Bull B, the percentage of vacuolated sperm cells bound to the zona pellucida (73.3 ± 7.8%) did not differ from that in the inseminate. The mean number of sperm cells binding to fertilized oocytes was higher than to unfertilized oocytes for both bulls (P < 0.05). In Experiment 2, 748 salt-stored oocytes (zonae) were inseminated with semen from the same 2 bulls to determine the ability of spermatozoa to penetrate the zona pellucida. The percentage of zonae penetrated by spermatozoa from Bull A (69.9 ± 3.5%; a mean of 2.4 ± 2.3 spermatozoa) was lower (P < 0.05) than from Bull B (96.5 ± 14.7%; a mean of 11.3 ± 9.9). Although the proportion of vacuolated sperm cells from Bull A that bound to the zona pellucida did not differ from that in the inseminate, the proportion of those penetrating the zona pellucida (52.7%) was lower (P < 0.05). In summary, vacuolated sperm cells apparently gained access to the oocyte and bound to the zona pellucida, but they penetrated the zona pellucida at a lower rate and apparently did not form normal male pronuclei.     

Reproductive characteristics of female Bengal tigers,in Ranthambhore Tiger Reserve,India

Reproductive characteristics of tigers (Panthera tigris) are important to understand population viability. We studied the reproductive parameters of female Bengal tigers (P. t. tigris) in a dry, tropical, deciduous habitat in Ranthambhore Tiger Reserve (RTR), western India, from April 2005 to March 2010. We monitored tigers by direct observation and with cameras placed throughout their habitat. The potential breeding population included 13 adult females. The average age at first reproduction was 3.3 years; 34 cubs were born during the study period (6.2?±?0.82 per year). Sixty-six percent of the births occurred between October and December. Mean litter size was 2.26?±?0.52 (n?=?13, range?=?1–3). The sex ratio of 32 cubs was 1.29 M:1.00 F. The survival rate of cubs (<12 months) was 85 % (95 % CI?=?0.68–0.94), whereas that of juveniles (12–24 months), and subadults (24–36 months) was 79 % (95 % CI?=?0.61–0.91). All breeding females were >3 years old. Only 2 of the 13 females reproduced twice during the 5 years of the study. The birth interval was 33.4?±?3.7 months (range 24–65 months). The mean reproductive rate was 0.59?±?0.23 cubs/female/year. Our study indicates that tiger populations can grow rapidly if the habitat provides adequate protection, an adequate population of prey, and minimal to no poaching.     

The effects of high temperature and roof modification on physiological responses of swamp buffalo (Bubalus bubalis) in the tropics

The objective of the experiments reported here was to measure the effects of cooling techniques (Modified roof vs Normal roof) on the performance and physiology of 12 young male buffaloes with a similar live weight of 160 kg. The study was conducted at Chainat Agriculture and Technology College, Chainat Province, Thailand. The animals were divided randomly into two groups, each group comprising six buffaloes, and the two groups were studied to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects’ physiological responses to heat stress under hot humid conditions. The modified roof resulted in lowered heat stress in buffaloes compared to those under a standard roof. The difference was shown by the buffaloes having a significantly lower mean rectal temperature (39.14?±?0.07 vs 40.00?±?0.10°C) and plasma cortisol (2.14?±?0.24 vs 3.38?±?0.37 ng/ml). The average daily water consumption was significantly lower in the MR group (MR, 29.71?±?0.86 vs NR, 34.14?±?1.06 L head ^?1 day^?1), while there was a tendency for the roughage intake to be higher in the MR group compared to that of the NR group (MR, 5.88?±?0.18 vs NR, 6.44?±?0.19 kg head-1 ^?1 day^?1; P?=?0.0508). It was concluded that roof modification facilitated a reduction in heat load from roof re-radiation, and was an effective means of alleviating thermal stress in young buffaloes.     

Calcium ion supplementation increases brook trout Salvelinus fontinalis spermatozoa activation at the end of the spawning season

The role of environmental ion composition and osmolality in calcium ion (Ca²⁺) signalling of spermatozoa activation over the course of the spawning period of brook trout Salvelinus fontinalis was investigated. Motility at the end of spawning was low (mean ± s.d. of 5 ± 2% motile spermatozoa with curvilinear velocity of 25 ± 8 µm s^?1). Addition of 10 mM Ca²⁺ to the activation medium resulted in values similar to those recorded during the middle of the spawning period (mean ± s.d. of 95 ± 6% motile spermatozoa with curvilinear velocity of 130 ± 15 µm s^?1).     

Optimisation of the spray drying process of formulating the post-harvest biocontrol agent Meyerozyma caribbica

In this study, conditions of the spray-drying process of Meyerozyma caribbica were optimised using response surface methodology (RSM). The effect of three parameters (protective agent, inlet air temperature and protective agent concentration) on the cell viability of Meyerozyma caribbica was evaluated. Each parameter was evaluated at three levels. All of the evaluated factors presented an effect on the viability of the control agent. According to RSM, optimal conditions include the use of trehalose with a concentration of 7.75% (w/v) and inlet air temperature of 112.5°C. The validation of the optimal spray-drying conditions allows obtaining a formulation of M. caribbica with 95.41?±?0.93% viability, 5?±?0.37% humidity and a_w of 0.33?±?0.11. Storage for six months at 4°C presented a 5% loss in cell viability.     

Right ventricular size and function under riociguat in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (the RIVER study)

Background

Riociguat is a soluble guanylate cyclase stimulator approved for pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTPEH). The objective of this study was to evaluate right heart size and function assessed by echocardiography during long term treatment with riociguat.

Methods

Patients who started riociguat treatment (1.0–2.5?mg tid) within the trials phase II, PATENT, PATENTplus, EAS, CHEST and continued treatment for 3–12?months were included in this study. Echocardiography was analysed off-line at baseline, after 3, 6 and 12?months by investigators who were blinded to clinical data. Last and baseline observation carried forward method (LOCF, BOCF) were performed as sensitivity analysis.

Results

Seventy-one patients (45% PAH, 55% CTEPH; 53.5% female; 60?±?13?years, mean pulmonary arterial pressure 46?±?10?mmHg, mean PVR 700?±?282dynes·sec·cm-5) were included. After 6?months, RA and RV area, RV thickness tricuspid regurgitation velocity showed a significant reduction. After 12?months, patients receiving riociguat therapy showed a significant reduction in right atrial (??2.6?±?4.4?cm2, 95% CI -3.84, ??1.33; p?<?0.001, n?=?49) and right ventricular (RV) area (??3.5?±?5.2?cm2, 95% CI -5.1, ??1.9; p?<?0.001; n?=?44), RV thickness (??0.76?±?2.2?mm, 95% CI -1.55, 0.03; n?=?32), and a significant increase in TAPSE (2.95?±?4.78?mm, 95% CI 1.52, 4.39; n?=?45) and RV fractional area change (8.12?±?8.87?mm, 95% CI 4.61, 11.62; n?=?27).Both LOCF and BOCF showed similar results but lower effect sizes.

Conclusion

Patients under long-term treatment with riociguat show significantly reduced right heart size and improved RV function in PAH and CTEPH. Further controlled prospective studies are needed to confirm these results.

     

Sperm losses during deep-freeze processing of bull semen

Ejaculates collected from 12 bulls were split and processed either by normal deep-freeze procedure including cooling to 4°C prior to glycerolisation and equilibration or by a modified procedure where glycerolisation and equilibration were carried out at ambient temperature (18°C). Semen from both treatments was packed into 0.25-ml French straws and frozen on horizontal racks in liquid nitrogen vapour. The concentration of spermatozoa recovered from straws from each treatment had a mean difference of 12.6 ± 2.7 million per millilitre (p<0.001). The 11% lower concentration of spermatozoa in the normally processed frozen semen was associated with sperm adhering to cold glassware.     

PARADOXICAL POST-EXERCISE RESPONSES OF ACYLATED GHRELIN AND LEPTIN DURING A SIMULATED NIGHT SHIFT

Approximately 10% of employees undertake night work, which is a significant predictor of weight gain, possibly because responses to activity and eating are altered at night. It is known that the appetite-related hormone, acylated ghrelin, is suppressed after an acute bout of exercise during the day, but no researcher has explored whether evening exercise alters acylated ghrelin and other appetite-related outcomes during a subsequent night shift. Six healthy men (mean?±?SD: age 30?±?8 yrs, body mass index 23.1?±?1.1?kg/m²) completed two crossover trials (control and exercise) in random order. Participants fasted from 10:00?h, consumed a test meal at 18:00?h, and then cycled at 50% peak oxygen uptake or rested between 19:00–20:00?h. Participants then completed light activities during a simulated night shift which ended at 05:00?h. Two small isocaloric meals were consumed at 22:00 and 02:00?h. Venous blood samples were drawn via cannulation at 1?h intervals between 19:00–05:00?h for the determination of acylated ghrelin, leptin, insulin, glucose, triglyceride, and non-esterified fatty acids concentrations. Perceived hunger and wrist actimetry were also recorded. During the simulated night shift, mean?±?SD acylated ghrelin concentration was 86.5?±?40.8 pg/ml following exercise compared with 71.7?±?37.7 pg/ml without prior exercise (p?=?0.015). Throughout the night shift, leptin concentration was 263?±?242 pg/ml following exercise compared with 187?±?221 pg/ml without prior exercise (p?=?0.017). Mean levels of insulin, triglyceride, non-esterified fatty acids, and wrist actimetry level were also higher during the night shift that followed exercise (p?<?0.05). These data indicate that prior exercise increases acylated ghrelin and leptin concentrations during a subsequent simulated night shift. These findings differ from the known effects of exercise on acylated ghrelin and leptin during the day, and therefore have implications for energy balance during night work. (Author correspondence: c.j.morris@2006.ljmu.ac.uk).     

Direct effect of estradiol-17β on progesterone accumulation by ovarian granulosa cells from rhesus monkeys

We have previously demonstrated that estradiol-17β (E₂) administered in vivo induces atresia of the dominant ovarian follicle (DF). Whether this effect is exerted directly at the ovarian level or by central mediation has not been confirmed. The present study was designed to assess whether E₂ in amounts similar to those found in monkey follicular fluid (FF) directly alters in vitro progesterone (P) accumulation by granulosa cells (GC) aspirated from follicles in cycling rhesus monkeys. Follicular contents were aspirated from three to five animals on each of days 8–13 of the cycle. GC were plated at a density of 50,000 viable GC/0.5 ml medium; GC were incubated with 0 or 2–2,000 ng/ml E₂, and cultures were maintained for 72 h. P accumulation by GC collected on day 8 and treated with 2 ng/ml E₂ was augmented 37.5 ± 5.5% (X ± S. E. M.; P<.05) over controls but was diminished significantly at 20 ng/ml ( ?55 ± 18% with respect to controls), 200 ng/ml ( ?73.7 ± 13.2%), and 2,000 ng/ml ( ?77.3 ± 18.4%). A similar dose-response relationship was noted on other cycle days. At a concentration of 2,000 ng/ml, E₂ significantly reduced P 91.5 ± 8.5% (day 10), 81.5 ± 18.5% (day 11), 84.3 ± 4.7% (day 12), and 53.7 ± 15.8% (day 13). We conclude that E₂ at concentrations found in FF can inhibit P output by monkey GC through a direct action.     

Effects of times and storage conditions of Duddingtonia flagrans chlamydospores in sodium alginate pellets on its nematode predatory ability

This study aimed to determine the effects of Duddingtonia flagrans contained in sodium alginate pellets on trichostrongylide larvae under different storage conditions and durations. The in vitro predatory activity of D. flagrans in pellets against trichostrongylide larvae in sheep faeces were assessed at 0, 1, 3, 6, 9, and 12 months after the pellet was stored under four different conditions (i.e. ?20, 4°C, outdoors, and indoors). These results revealed that the numbers of larvae in faeces of sheep treated with pellets containing chlamydospores (treatment groups) were significantly lower than those in the control groups (without chlamydospores) for all trial months under four storage conditions for different durations (p?<?.05). The obtained reduction rates of the infective larvae (L3) in the four treatment groups ranged from 45.62% to 96.73% throughout the entire experiment. The overall mean L3 reduction percentages were 89.22%?±?3.74%, 88.97%?±?1.33%, 68.60%?±?14.31%, and 75.45%?±?13.18% for 4°C refrigeration, ?20°C refrigeration, indoor, and outdoor conditions, respectively. The pellets stored under these storage conditions for a year were provided to sheep for ingestion (in vivo test), and the results showed that the number of recovered larvae in sheep faeces at 24?h after ingestion were significantly lower than that before ingestion. For in vivo test, the L3 reduction percentage in the faeces was 90.99% (?20°C), 74.81% (outdoor), 83.53% (4°C), and 65.60% (indoor). Under the four storage conditions, D. flagrans spores contained in the pellets can maintain their survival ability to a varying degree in a year.     

Synthesis,Acoustic Stability,and Pharmacologic Activities of Papaverine-Loaded Echogenic Liposomes for Ultrasound Controlled Drug Delivery

Background: development of encapsulated therapeutics that could be released upon ultrasound exposure has strong implications for enhancing drug effects at the target site. We have developed echogenic liposomes (ELIP) suitable for ultrasound imaging of blood flow and ultrasound-mediated intravascular drug release. Papaverine was chosen as the test drug because its clinical application requires high concentration in the target vascular bed but low concentration in the systemic circulation. Methods: the procedure for preparation of standard ELIP was modified by including Papaverine hydrochloride in the lipid hydration solution, followed by three freeze-thaw cycles to increase encapsulation of the drug. Sizing and encapsulation pharmacokinetics were performed using a Coulter counter and a phosphodiesterase activity assay. Stability of Papaverine-loaded ELIP (PELIP) was monitored with a clinical diagnostic ultrasound scanner equipped with a linear array transducer at a center frequency of 4.5 MHz by assessing the mean digital intensity within a region of interest over time. The stability of PELIP was compared to those of standard ELIP and Optison?. Results: relative to standard ELIP, PELIP were larger (median diameter?=?1.88?±?0.10 μm for PELIP vs 1.08?±?0.15 μm for ELIP) and had lower Mean Gray Scale Values (MGSV) (92?±?24.8 for PELIP compared to 142.3?±?10.7 for ELIP at lipid concentrations of 50 μg/ml). The maximum loading efficiency and mean encapsulated concentration were 24%?±?7% and 2.1?±?0.7 mg/ml, respectively. Papaverine retained its phosphodiesterase inhibitory activity when associated with PELIP. Furthermore, a fraction of this activity remained latent until released by dissolution of liposomal membranes with detergent. The stability of both PELIP and standard ELIP were similar, but both are greater than that of Optison?. Conclusions: our results suggest that PELIP have desirable physical, biochemical, biological, and acoustic characteristics for potential in vivo administration and ultrasound-controlled drug delivery.     

Mangrove rehabilitation on Carey Island,Malaysia: an evaluation of replanting techniques and sediment properties

We assess the suitability of conventional replanting techniques of Rhizophora mucronata and the relationship with soil properties, and compare the differences between rehabilitation and non-rehabilitation sites, on Carey Island, Malaysia. The average survival rate of planted seedlings at the rehabilitation site was 46% in the first six months, gradually reducing to complete mortality after one year, while no survival was recorded at the non-rehabilitation site from the beginning. Over the short period, survival of the clumped planting technique yielded the highest survival rate (75%) compared with random (33%) and uniform (30%) techniques; with a height increment of 2.48?±?1.87?cm/month, diameter increment of 0.49?±?0.81?mm/month, leaf increment of 2.05?±?2.80 and chlorophyll content of 32.08?±?5.80 SPAD (= Soil Plant Analysis Development values). Fifteen new recruits of Avicennia spp. with a 60% survival rate were recorded in the rehabilitation site at the end of the study. Soil texture changed significantly at the rehabilitation site from sandy loam (clay, 2.85%; silt 33.93%; sand, 63.21%) to silty loam (clay, 1.88%; silt 60.74%; sand, 37.38%). Soil nutrients: carbon (C), nitrogen (N) and potassium (K) were significantly higher in the top 40?cm at the rehabilitation site while phosphorus (P) was lower. We argue that nutrient differences between the rehabilitation and non-rehabilitation sites affected the health of both planted and wild seedlings and ultimately the success of the rehabilitation effort. As the soil condition improves at the rehabilitation site, natural recruitment would be the best available option in this restoration process.     

Laboratory assessment of the antifouling potential of a soluble-matrix paint laced with the natural compound polygodial

Polygodial is a potent and selective inhibitor of ascidian metamorphosis that shows promise for controlling fouling by ascidians in bivalve aquaculture. The current study examined the potency of, and associated effects of seawater exposure on, a rosin-based soluble-matrix paint laced with 0.08–160?ng?polygodial?g^?1 wet paint matrix. Paint-coated surfaces were soaked in seawater for 0, 2, 4 or 12?weeks prior to screening for antifouling activity using a bioassay based on the nuisance ascidian Ciona savignyi Herdman. Mortality was greater (mean 50% lethal concentration: 5?±?2?ng?g^?1; mean 75% lethal concentration: 17?±?4?ng?g^?1) and metamorphosis was inhibited (mean 50% anti-metamorphic concentration: 2?±?0.4?ng?g^?1; mean 75% anti-metamorphic concentration: 15?±?10?ng?g^?1) in C. savignyi larvae exposed to polygodial-laced soluble-matrix paints, relative to control paints without polygodial. Soaking in seawater prior to testing reduced the efficacy of the formulation up to nearly 12-fold, but even after soaking for 12?weeks paints laced with polygodial at 160?ng?g^?1 wet paint matrix prevented ?90% of the larvae of C. savignyi from completing metamorphosis. The outcome of this experiment provides a positive first step in evaluating the suitability of polygodial-laced soluble-matrix paints for use in aquaculture.