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Fulltext Mechanisms of sex determination and transmission ratio distortion in Aedes aegypti

Hoang KP, Teo TM, Ho TX, Le VS

Parasit Vectors, 2016 Jan 28;9:49.
PMID: 26818000 DOI: 10.1186/s13071-016-1331-x

BACKGROUND: More effective mosquito control strategies are urgently required due to the increasing prevalence of insecticide resistance. The sterile insect technique (SIT) and the release of insects carrying a dominant lethal allele (RIDL) are two proposed methods for environmentally-friendly, species-targeted population control. These methods may be more suitable for developing countries if producers reduce the cost of rearing insects. The cost of control programs could be reduced by producing all-male mosquito populations to circumvent the isolation of females before release without reducing male mating competitiveness caused by transgenes.
RESULTS: An RNAi construct targeting the RNA recognition motif of the Aedes aegypti transformer-2 (tra-2) gene does not trigger female-to-male sex conversion as commonly observed among dipterous insects. Instead, homozygous insects show greater mortality among m-chromosome-bearing sperm and mm zygotes, yielding up to 100% males in the subsequent generations. The performance of transgenic males was not significantly different to wild-type males in narrow-cage competitive mating experiments.
CONCLUSION: Our data provide preliminary evidence that the knockdown of Ae. aegypti tra-2 gene expression causes segregation distortion acting at the level of gametic function, which is reinforced by sex-specific zygotic lethality. This finding could promote the development of new synthetic sex distorter systems for the production of genetic sexing mosquito strains.

Matched MeSH terms: Reproduction
Medicinal plants: conception / contraception

Chaing HS, Merino-chavez G, Yang LL, Wang FN, Hafez ES

Adv Contracept Deliv Syst, 1994;10(3-4):355-63.
PMID: 12287843
Matched MeSH terms: Reproduction
Fulltext Menstrual food restrictions and taboos: A qualitative study on rural, resettlement and urban indigenous Temiar of Malaysia

Syed Abdullah SZ

PLoS One, 2022;17(12):e0279629.
PMID: 36574445 DOI: 10.1371/journal.pone.0279629

Menstruation is arguably the first stage in a woman's reproductive cycle. Among the Temiar, as in many other traditional societies, menstruation represents a time during which a woman is considered to be vulnerable or polluted and there may be food or behavior avoidances and restrictions. The Temiar is one of the eighteen indigenous sub-ethnic groups in Peninsular Malaysia. The objective of this study was to examine the food restrictions and taboos imposed on menstruating Temiar women. A total of 38 participants from four different locations took part in five focus group discussions which represents different lifestyle experiences of the Temiar sub-ethnic group. The findings unfolds many practices: foods to be avoided and spirit in the landscape in order to protect the menstruating woman; isolating the menstruating woman in order to protect the community; consequences of not observing the menstruation food taboos and maintenance of the menstrual taboos. The menstruating women in all locations were prohibited from consuming salt, cooking oils, wild or domesticated animals, and Monosodium glutamate to protect themselves from the excessive flow of menstrual blood and future ill-health. They must eat separately from others because they are deemed polluted and dangerous to the community. The study concludes that the taboos directed towards the menstruating women often do have a caring and protective intention. Menstrual restrictions function not only to protect the menstruating women and the community but also to keep intact the symbolic boundary between human and the non-human world from which disease and weakness comes.

Matched MeSH terms: Reproduction
Fulltext Microalgae associated with Leptoconops breeding sites in selected sandy beaches of Malaysia

Rohani A, Khadri MS, Lee HL

Trop Biomed, 2006 Dec;23(2):164-71.
PMID: 17322818 MyJurnal

A study was carried out to investigate correlation between presence of specific microalgal species and Leptoconops biting midge larvae in its breeding habitats. Sand samples containing microalgae were collected from the beach where the midges were most commonly biting and from sand beaches which are potential as breeding habitats of Leptoconops. The survey covered sand beaches from 12 seperate islands. At all sites, the Bacillariophyta constituted the largest representatives of the microalgae community with the majority from the Naviculaceae family. A total of 24 microalgal species were identified from the sand samples collected from the study sites. Sand samples from Kentot Kecil Island had the highest number of algal species (11.0) and the highest algae species diversity ( Shanon-Weiner Diversity Index, H' = 0.884). Besar Island (Johor) had the lowest number of algal species (2.0) whereas Tengol A Island had the lowest algae species diversity (H'=0.234). Highest similarity index was recorded between sand samples collected from Tengol A Island and Tengol B Island (75.0%) followed by Besar Island (Melaka) and Tengol B Island (62.0 %). The variation between other islands were relatively high. Virtually many kinds of algae were found where Leptoconops were breeding but Fragilaria intermedia, Mastigloia minuta and Navicula advena were particularly common.

Matched MeSH terms: Reproduction/physiology
Fulltext Mixed Mating System Are Regulated by Fecundity in Shorea curtisii (Dipterocarpaceae) as Revealed by Comparison under Different Pollen Limited Conditions

Tani N, Tsumura Y, Fukasawa K, Kado T, Taguchi Y, Lee SL, et al.

PLoS One, 2015;10(5):e0123445.
PMID: 25938512 DOI: 10.1371/journal.pone.0123445

The maintenance of mixed mating was studied in Shorea curtisii, a dominant and widely distributed dipterocarp species in Southeast Asia. Paternity and hierarchical Bayesian analyses were used to estimate the parameters of pollen dispersal kernel, male fecundity and self-pollen affinity. We hypothesized that partial self incompatibility and/or inbreeding depression reduce the number of selfed seeds if the mother trees receive sufficient pollen, whereas reproductive assurance increases the numbers of selfed seeds under low amounts of pollen. Comparison of estimated parameters of self-pollen affinity between high density undisturbed and low density selectively logged forests indicated that self-pollen was selectively excluded from mating in the former, probably due to partial self incompatibility or inbreeding depression until seed maturation. By estimating the self-pollen affinity of each mother tree in both forests, mother trees with higher amount of self-pollen indicated significance of self-pollen affinity with negative estimated value. The exclusion of self-fertilization and/or inbreeding depression during seed maturation occurred in the mother trees with large female fecundity, whereas reproductive assurance increased self-fertilization in the mother trees with lower female fecundity.

Matched MeSH terms: Reproduction/physiology
Fulltext Mixed breeding of Aedes aegypti (L.) and Aedes albopictus Skuse in four dengue endemic areas in Kuala Lumpur and Selangor, Malaysia

Chen CD, Nazni WA, Lee HL, Seleena B, Mohd Masri S, Chiang YF, et al.

Trop Biomed, 2006 Dec;23(2):224-7.
PMID: 17322826 MyJurnal

Ovitrap surveillance was conducted in four dengue endemic areas in Kuala Lumpur and Selangor, Malaysia to determine the distribution and percentage of mixed breeding of both Aedes aegypti and Aedes albopictus. The percentage of mixed breeding in all study sites both indoors and outdoors accounted for 10 to 32 % from the total ovitraps collected. Ae. aegypti was found at a higher frequency than Ae. albopictus in these ovitraps. This study again indicates that ovitrap is a sensitive tool to attract gravid females of more than one mosquito species to oviposit in the container.

Matched MeSH terms: Reproduction/physiology
Fulltext Modelling infectious diseases with herd immunity in a randomly mixed population

Law KB, M Peariasamy K, Mohd Ibrahim H, Abdullah NH

Sci Rep, 2021 10 18;11(1):20574.
PMID: 34663839 DOI: 10.1038/s41598-021-00013-2

The conventional susceptible-infectious-recovered (SIR) model tends to magnify the transmission dynamics of infectious diseases, and thus the estimated total infections and immunized population may be higher than the threshold required for infection control and eradication. The study developed a new SIR framework that allows the transmission rate of infectious diseases to decline along with the reduced risk of contact infection to overcome the limitations of the conventional SIR model. Two new SIR models were formulated to mimic the declining transmission rate of infectious diseases at different stages of transmission. Model A utilized the declining transmission rate along with the reduced risk of contact infection following infection, while Model B incorporated the declining transmission rate following recovery. Both new models and the conventional SIR model were then used to simulate an infectious disease with a basic reproduction number (r0) of 3.0 and a herd immunity threshold (HIT) of 0.667 with and without vaccination. Outcomes of simulations were assessed at the time when the total immunized population reached the level predicted by the HIT, and at the end of simulations. Further, all three models were used to simulate the transmission dynamics of seasonal influenza in the United States and disease burdens were projected and compared with estimates from the Centers for Disease Control and Prevention. For the simulated infectious disease, in the initial phase of the outbreak, all three models performed expectedly when the sizes of infectious and recovered populations were relatively small. As the infectious population increased, the conventional SIR model appeared to overestimate the infections even when the HIT was achieved in all scenarios with and without vaccination. For the same scenario, Model A appeared to attain the level predicted by the HIT and in comparison, Model B projected the infectious disease to be controlled at the level predicted by the HIT only at high vaccination rates. For infectious diseases with high r0, and at low vaccination rates, the level at which the infectious disease was controlled cannot be accurately predicted by the current theorem. Transmission dynamics of infectious diseases with herd immunity can be accurately modelled by allowing the transmission rate of infectious diseases to decline along with the reduction of contact infection risk after recovery or vaccination. Model B provides a credible framework for modelling infectious diseases with herd immunity in a randomly mixed population.

Matched MeSH terms: Basic Reproduction Number
Fulltext Modelling the Effect of a Novel Autodissemination Trap on the Spread of Dengue in Shah Alam and Malaysia

Liang Y, Ahmad Mohiddin MN, Bahauddin R, Hidayatul FO, Nazni WA, Lee HL, et al.

Comput Math Methods Med, 2019;2019:1923479.
PMID: 31481976 DOI: 10.1155/2019/1923479

In this paper, we will start off by introducing the classical Ross-Macdonald model for vector-borne diseases which we use to describe the transmission of dengue between humans and Aedes mosquitoes in Shah Alam, which is a city and the state capital of Selangor, Malaysia. We will focus on analysing the effect of using the Mosquito Home System (MHS), which is an example of an autodissemination trap, in reducing the number of dengue cases by changing the Ross-Macdonald model. By using the national dengue data from Malaysia, we are able to estimate λ, which represents the initial growth rate of the dengue epidemic, and this allows us to estimate the number of mosquitoes in Malaysia. A mathematical expression is also constructed which allows us to estimate the potential number of breeding sites of Aedes mosquitoes. By using the data available from the MHS trial carried out in Section 15 of Shah Alam, we included the potential effect of the MHS into the dengue model and thus modelled the impact MHS has on the spread of dengue within the trial area. We then extended our results to analyse the effect of the MHSs on reducing the number of dengue cases in the whole of Malaysia. A new model was constructed with a basic reproduction number, R0,MalaMHS, which allows us to identify the required MHSs coverage needed to achieve extinction in Malaysia. Numerical simulations and tables of results were also produced to illustrate our results.

Matched MeSH terms: Basic Reproduction Number/statistics & numerical data
Fulltext Modelling the effect of temperature change on the extrinsic incubation period and reproductive number of Plasmodium falciparum in Malaysia

Chua TH

Trop Biomed, 2012 Mar;29(1):121-8.
PMID: 22543612 MyJurnal

According to the report of the Intergovernmental Panel on Climate Change (IPCC), Malaysia will experience an increase of 3-5°C in the future. As the development of the malaria parasite, Plasmodium falciparum, is sensitive to temperature, we investigated, using computer models, the effect of increase of 3º and 5ºC on the possible changes in the epidemiology of malaria transmission of P. falciparum in Malaysia. Four environmentally different locations were selected: Kuala Lumpur (KL), Cameron Highlands (CH), Kota Kinabalu (KK) and Kinabalu Park (KP). The extrinsic incubation period (EIP) was estimated using hourly temperatures and the mean daily temperatures. The EIP values estimated using the mean daily temperature were lower than those computed from hourly temperatures in warmer areas (KL, KK), but higher in the cooler areas (CH, KP). The computer simulations also indicated that the EIP will be decreased if the temperature was raised by 3º or 5ºC, with the effect more pronounced for the greater temperature increase, and for the cooler places. The vector cohort that is still alive at a time to transmit malaria (s(EIP)) also increased when the temperature was raised, with the increase more pronounced in the cooler areas. This study indicates an increase in temperature will have more significant effect in shortening the EIP in a cooler place (eg CH, KP), resulting in a greater s(EIP), and consequently increasing the transmission intensity and malaria risk. A temperature increase arising from the global climate change will likely affect the epidemiology of malaria in Malaysia, especially in the cooler areas.

Matched MeSH terms: Basic Reproduction Number
Molecular, cellular, morphological, physiological and behavioral aspects of gonadotropin-inhibitory hormone

Ubuka T, Son YL, Tsutsui K

Gen Comp Endocrinol, 2016 Feb 1;227:27-50.
PMID: 26409890 DOI: 10.1016/j.ygcen.2015.09.009

Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that was isolated from the brains of Japanese quail in 2000, which inhibited luteinizing hormone release from the anterior pituitary gland. Here, we summarize the following fifteen years of researches that investigated on the mechanism of GnIH actions at molecular, cellular, morphological, physiological, and behavioral levels. The unique molecular structure of GnIH peptide is in its LPXRFamide (X=L or Q) motif at its C-terminal. The primary receptor for GnIH is GPR147. The cell signaling pathway triggered by GnIH is initiated by inhibiting adenylate cyclase and decreasing cAMP production in the target cell. GnIH neurons regulate not only gonadotropin synthesis and release in the pituitary, but also regulate various neurons in the brain, such as GnRH1, GnRH2, dopamine, POMC, NPY, orexin, MCH, CRH, oxytocin, and kisspeptin neurons. GnIH and GPR147 are also expressed in gonads and they may regulate steroidogenesis and germ cell maturation in an autocrine/paracrine manner. GnIH regulates reproductive development and activity. In female mammals, GnIH may regulate estrous or menstrual cycle. GnIH is also involved in the regulation of seasonal reproduction, but GnIH may finely tune reproductive activities in the breeding seasons. It is involved in stress responses not only in the brain but also in gonads. GnIH may inhibit male socio-sexual behavior by stimulating the activity of cytochrome P450 aromatase in the brain and stimulates feeding behavior by modulating the activities of hypothalamic and central amygdala neurons.

Matched MeSH terms: Reproduction/physiology*
Fulltext Monosodium glutamate induced oxidative stress in accessory reproductive organs of male sprague-dawley rats

Erni Norfardila Abu Hanipah, Nor Janna Yahya, Esther Mathias Ajik, Nur Afizah Yusoff, Izatus Shima Taib

Jurnal Sains Kesihatan Malaysia, 2018;16(101):67-73.
MyJurnal

Monosodium glutamate (MSG) is widely used as a food additive but its excessive intake leads to oxidative stress of several organs. However, the oxidative effect of MSG on male accessory reproductive organs remains unclear. Therefore, the aim of this study was to evaluate the effect of MSG on the status of oxidative stress and morphological alterations in the male accessory reproductive organs such as epididymis, prostate glands and seminal vesicle of Sprague-Dawley rats. A total of 24 male Sprague-Dawley rats were randomly divided into three groups with 8 rats per group. Control group received distilled water (1 ml/kg) while MSG60 and MSG120 received 60 mg/kg and 120 mg/kg of MSG, respectively. All the substances were administered via force feed oral for 28 consecutive days. At the end of the study, the rats were sacrificed to obtain the accessory organs for biochemical analysis and histological observations. The SOD activity in the epididymis showed a significant increase in MSG60 and MSG120 compared to control (p < 0.05). The GSH levels in the epididymis of MSG 120 showed a significant reduction (p < 0.05) compared to the control group. The levels of MDA and PC in the epididymis and prostate gland of MSG60 and MSG120 showed a significant increased (p < 0.05) compared to the control group. Histological alterations were found in the epididymis and prostate gland of MSG treated rats. In conclusion, MSG at both doses induced oxidative stress in the epididymis and prostate gland of experimental rats.

Matched MeSH terms: Reproduction
Fulltext Morphological Evidence for Functional Crosstalk Between Multiple GnRH Systems in the Male Tilapia, Oreochromis niloticus

Ogawa S, Parhar I

Front Endocrinol (Lausanne), 2020;11:586.
PMID: 32982977 DOI: 10.3389/fendo.2020.00586

Gonadotropin-releasing hormone (GnRH) is a reproductive neuropeptide, which controls vertebrate reproduction. In most vertebrates, there are more than two GnRH orthologs in the brain. In cichlid fish, the Nile tilapia (Oreochromis niloticus), GnRH1 is the primary hypophysiotropic hormone, while GnRH2 and GnRH3 are non-hypophysiotropic but neuromodulatory in function. Hypophysiotropic GnRH neurons are thought to inter-communicate, while it remains unknown if hypophysiotropic and non-hypophysiotropic GnRH systems communicate with each other. In the present study, we examined interrelationship between three GnRH types using specific antibodies raised against their respective GnRH associated peptide (GAP) sequence. Double-immunofluorescence labeling coupled with confocal microscopy revealed that in sexually mature males, GnRH-GAP1-immunoreactive (-ir) processes are in proximities of GnRH-GAP3-ir cell somata in the terminal nerve, while GnRH-GAP1-ir cell somata were also accompanied by GnRH-GAP3-ir processes in the preoptic area. However, such interaction was not seen in immature males. Further, there was no interaction between GnRH-GAP2 and GnRH-GAP1 or GnRH-GAP3 neurons. Single cell gene expression analysis revealed co-expression of multiple GnRH receptor genes (gnrhr1 and gnrhr2) in three GnRH-GAP cell types. In mature males, high levels of gnrhr2 mRNA were expressed in GnRH-GAP1-ir cells. In immature males, gnrhr1 and gnrhr2 mRNAs are highly expressed in GnRH-GAP3-ir cells. These results suggest heterologous interactions between the three GnRH-GAP cell types and their potential functional interaction during different reproductive stages.

Matched MeSH terms: Reproduction/physiology
Mutual compensation of the effects of religious and ethnic homogamy on reproduction

Huber S, Fieder M

Am J Hum Biol, 2018 01;30(1).
PMID: 28960565 DOI: 10.1002/ajhb.23064

OBJECTIVES: Homogamy, mating based on similarity, has been demonstrated for a great variety of traits such as age, education, religion, and physical and psychological traits. Recently, pro-fertile effects of religious as well as educational homogamy have been reported. We investigate whether ethnic homogamy also has a pro-fertile effect and whether ethnic and religious homogamy interact in their putative effects on reproduction (in terms of average number of offspring).
METHODS: We analyzed the association between ethnic as well as religious homogamy and woman's average number of offspring based on census data from ten countries provided by IPUMS international, encompassing a total of 1,485,433 married women aged 46-60 years (who have thus completed or almost completed reproduction) and their spouses.
RESULTS: We find a clear pro-fertile but nonadditive effect of both ethnic and religious homogamy, which is most pronounced in the case of double homogamy. Our results further indicate that homogamy for one trait may compensate for heterogamy of the other, albeit countries differ regarding which trait compensates for the other.
CONCLUSIONS: We suggest that the interaction between ethnic homogamy, religious homogamy, and reproduction provides an interesting example for gene-culture co-evolution.

Matched MeSH terms: Reproduction*
Fulltext Neighbouring-group composition and within-group relatedness drive extra-group paternity rate in the European badger (Meles meles)

Annavi G, Newman C, Dugdale HL, Buesching CD, Sin YW, Burke T, et al.

J Evol Biol, 2014 Oct;27(10):2191-203.
PMID: 25234113 DOI: 10.1111/jeb.12473

Extra-group paternity (EGP) occurs commonly among group-living mammals and plays an important role in mating systems and the dynamics of sexual selection; however, socio-ecological and genetic correlates of EGP have been underexplored. We use 23 years of demographic and genetic data from a high-density European badger (Meles meles) population, to investigate the relationship between the rate of EGP in litters and mate availability, mate incompatibility and mate quality (heterozygosity). Relatedness between within-group assigned mothers and candidate fathers had a negative quadratic effect on EGP, whereas the number of neighbouring-group candidate fathers had a linear positive effect. We detected no effect of mean or maximum heterozygosity of within-group candidate fathers on EGP. Consequently, EGP was associated primarily with mate availability, subject to within-group genetic effects, potentially to mitigate mate incompatibility and inbreeding. In badgers, cryptic female choice, facilitated by superfecundation, superfoetation and delayed implantation, prevents males from monopolizing within-group females. This resonates with a meta-analysis in group-living mammals, which proposed that higher rates of EGP occur when within-group males cannot monopolize within-group females. In contrast to the positive meta-analytic association, however, we found that EGP associated negatively with the number of within-group assigned mothers and the number of within-group candidate fathers; potentially a strategy to counter within-group males committing infanticide. The relationship between the rate of EGP and socio-ecological or genetic factors can therefore be intricate, and the potential for cryptic female choice must be accounted for in comparative studies.

Matched MeSH terms: Reproduction*
Fulltext No evidence for successful interspecific cross-mating of transgenic Aedes aegypti (L.) and wild type Aedes albopictus Skuse

Lee HL, Aramu M, Nazni WA, Selvi S, Vasan S

Trop Biomed, 2009 Dec;26(3):312-9.
PMID: 20237445

The natural and artificial mating of laboratory bred Aedes albopictus and transgenic Aedes aegypti RIDL-513A-Malaysian strain was conducted. The experiment consisted of crossmating of homologous Ae. aegypti RIDL female symbol X Ae. aegypti RIDL male symbol and reciprocal Ae. aegypti RIDL female symbol X Ae. albopictus WT male symbol. The other set comprised homologous Ae. albopictus WT female symbol X Ae. albopictus WT male symbol and reciprocal Ae. albopictus WT female symbol X Ae. aegypti RIDL male symbol. This study demonstrated that reproductive barriers exist between these two species. Cross insemination occurred between A. albopictus male and Ae. aegypti female and their reciprocals. There was 26.67% and 33.33% insemination rate in Ae. aegypti RIDL female cross-mating with A. albopictus WT male and Ae. albopictus female cross-mating with Ae. aegypti RIDL male, respectively. There was 0% hatchability in both directions of the reciprocals. There was also no embryonation of these eggs which were bleached. Although none of the female Ae. albopictus WT was inseminated in the cross-mating with Ae. albopictus WT female symbol X Ae. aegypti RIDL male symbol, a total of 573 eggs were obtained. The homologous mating was very productive resulting in both high insemination rate and hatchability rates. Generally there was a significantly higher insemination rate with artificial mating insemination of homologous than with artificial mating of reciprocal crosses. Interspecific mating between Ae. aegypti RIDL and Ae. albopictus wild type was not productive and no hybrid was obtained, indicating absence of horizontal transfer of introduced RIDL gene in Ae. aegypti to Ae. albopictus.

Matched MeSH terms: Reproduction
No evidence of carbon storage usage for seed production in 18 dipterocarp masting species in a tropical rain forest

Igarashi S, Yoshida S, Kenzo T, Sakai S, Nagamasu H, Hyodo F, et al.

Oecologia, 2024 Mar;204(3):717-726.
PMID: 38483587 DOI: 10.1007/s00442-024-05527-w

Most canopy species in lowland tropical rain forests in Southeast Asia, represented by Dipterocarpaceae, undergo mast reproduction synchronously at community level during a general flowering event. Such events occur at irregular intervals of 2-10 years. Some species do not necessarily participate in every synchronous mast reproduction, however. This may be due to a lack of carbohydrate resources in the trees for masting. We tested the hypothesis that interspecific differences in the time required to store assimilates in trees for seed production are due to the frequency of masting and/or seed size in each species. We examined the relationship between reproductive frequency and the carbon accumulation period necessary for seed production, and between the seed size and the period, using radiocarbon analysis in 18 dipterocarp canopy species. The mean carbon accumulation period was 0.84 years before seed maturation in all species studied. The carbon accumulation period did not have any significant correlation with reproductive frequency or seed size, both of which varied widely across the species studied. Our results show that for seed production, dipterocarp masting species do not use carbon assimilates stored for a period between the masting years, but instead use recent photosynthates produced primarily in a masting year, regardless of the masting interval or seed size of each species. These findings suggest that storage of carbohydrate resources is not a limiting factor in the masting of dipterocarps, and that accumulation and allocation of other resources is important as a precondition for participation in general flowering.

Matched MeSH terms: Reproduction
Fulltext Non-density dependent pollen dispersal of Shorea maxwelliana (Dipterocarpaceae) revealed by a Bayesian mating model based on paternity analysis in two synchronized flowering seasons

Masuda S, Tani N, Ueno S, Lee SL, Muhammad N, Kondo T, et al.

PLoS One, 2013;8(12):e82039.
PMID: 24391712 DOI: 10.1371/journal.pone.0082039

Pollinator syndrome is one of the most important determinants regulating pollen dispersal in tropical tree species. It has been widely accepted that the reproduction of tropical forest species, especially dipterocarps that rely on insects with weak flight for their pollination, is positively density-dependent. However differences in pollinator syndrome should affect pollen dispersal patterns and, consequently, influence genetic diversity via the mating process. We examined the pollen dispersal pattern and mating system of Shorea maxwelliana, the flowers of which are larger than those of Shorea species belonging to section Mutica which are thought to be pollinated by thrips (weak flyers). A Bayesian mating model based on the paternity of seeds collected from mother trees during sporadic and mass flowering events revealed that the estimated pollen dispersal kernel and average pollen dispersal distance were similar for both flowering events. This evidence suggests that the putative pollinators - small beetles and weevils - effectively contribute to pollen dispersal and help to maintain a high outcrossing rate even during sporadic flowering events. However, the reduction in pollen donors during a sporadic event results in a reduction in effective pollen donors, which should lead to lower genetic diversity in the next generation derived from seeds produced during such an event. Although sporadic flowering has been considered less effective for outcrossing in Shorea species that depend on thrips for their pollination, effective pollen dispersal by the small beetles and weevils ensures outcrossing during periods of low flowering tree density, as occurs in a sporadic flowering event.

Matched MeSH terms: Reproduction/genetics; Reproduction/physiology
Fulltext Numerical study of tides in the Malacca Strait with a 3-D model

Haditiar Y, Putri MR, Ismail N, Muchlisin ZA, Ikhwan M, Rizal S

Heliyon, 2020 Sep;6(9):e04828.
PMID: 32939416 DOI: 10.1016/j.heliyon.2020.e04828

Malacca Strait (MS) has an important role and potential for many countries. It is a major transportation route for oil and commodities across continents. In addition, various activities such as shipping, fishing, aquaculture, oil drilling, and energy are also carried out in MS. Tides strongly affect the MS environment so that it becomes a major parameter in MS management. This paper is the first study, which presents MS tidal hydrodynamics based on a baroclinic and nonhydrostatic approach. Tidal hydrodynamics in MS and the surrounding waters were assessed using tidal forces, temperature, salinity, and density. This study analyzes the amplitude, phase, current ellipses, and semi-major axis of the tides. These variables are obtained from the simulation results of the three-dimensional numerical models of M2 tides and combined tides (M2, S2, N2, K1, and O1) with nonhydrostatic models. Then the results obtained are verified by observation data. Amplitude and phase of the tidal wave in MS originate from two directions, namely the northern part of MS (Andaman Sea) and the South China Sea (SCS). Tides from the north of MS propagate into the MS, while tides from the SCS travel to Singapore Waters (SW) and the south of MS. This causes a complex residual flow in SW and shoaling in the middle of MS. Shoaling in the middle of MS is characterized by a large amplitude and semi-major, as in B. Siapiapi. The results of this analysis show that tidal waves are dominated by semidiurnal types rather than diurnal types. The M2 current ellipse has dominantly anticlockwise rotation along the west of the MS, while along the east of MS, it has generally a clockwise rotation.

Matched MeSH terms: Reproduction
Fulltext Nutritional anemia in pregnancy: a study at the maternity hospital, Kuala Lumpur

Tee ES, Kandiah M, Ali J, Kandiah V, Zahari MR, Kuladevan R, et al.

Malays J Reprod Health, 1984 Jun;2(1):32-50.
PMID: 12267519

The study presents recent data on the prevalence and pattern of nutritional anemia in the Maternity Hospital, Kuala Lumpur. A total of 309 pregnant women in their third trimester, of Malay, Chinese and Indian origin from the lower socio-economic strata were randomly selected for the study. Hematological indices (including Hb, PCV, MCHC, and TRBC), serum iron, transferrin saturation and ferritin, serum folate as well as protein and albumin were determined. Based on Hb and PCV values, 30-40 percent of the women could be considered anemic; approximately 50 percent of them presented with unsatisfactory serum iron, transferrin saturation and ferritin values; 60.9 percent had low serum folate levels; and about 30 percent may be considered to be of poor protein nutriture. Anemia in the study population was seen to be related mostly to iron and to a lesser extent, folate deficiency. Hematological, iron, folate and protein status was observed to be the poorest amongst the Indian women, better in the Malay group and generally the best amongst the Chinese women. Birth records of 169 of these women revealed that all of them had live births. Nearly all the infants were delivered by normal vaginal delivery (NVD) The mean gestational age was 38.6 weeks. One of the infants had a birth weight of <2.0 kg; incidence of low birth weight, <2.5 kg, was 8.3 percent. Although there was a trend of deteriorating hematological, iron and protein status of women from the 0, 1 -3 and >=4 parity groups, these differences were not statlstlcally significant.

Matched MeSH terms: Reproduction
Observations on Banteng cattle in Sabah

Copland RS

Trop Anim Health Prod, 1974 May;6(2):89-94.
PMID: 4414876
Matched MeSH terms: Reproduction

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