Sex-specific facilitation and reproduction of the gynodioecious cushion plant Arenaria polytrichoides on the Himalaya-Hengduan mountains,SW China

When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytrichiodes as a model species,we aimed to assess the sex-specific facilitation intensity of cushion plant by measuring the beneficiary cover ratio,and to assess the potential costs in cushion reproductive functions by measuring the flower and fruit cover ratios.The total beneficiary cover ratio was similar between females and hermaphrodites.Females produced much less flowers but more fruits than hermaphrodites.These results suggested that females and hermaphrodites possess similar facilitation intensity,and female cushion A.polytrichoides may allocate more resources saved from pollen production to seed production,while hermaphrodites possibly allocate more resources to pollen production hence reducing seed production.The surface areas covered by beneficiaries produced less flowers and fruits than areas without beneficiaries.In addition,strong negative correlations between beneficiary cover and flower cover were detected for both females and hermaphrodites,but the correlation strength were similar for these two sex morphs.However,the correlation between beneficiary cover and fruit cover was only significantly negative for females,suggesting that beneficiary plants negatively affect fruit reproduction of females while have neutral effects on hermaphrodites.All the results suggest that to facilitate other beneficiaries can induce reproductive costs on cushion A.polytrichoides,with females possibly suffering greater cost than hermaphrodites.Such differentiation in reproductive costs between sex morphs,in long-term perspective,may imply sex imbalance in population dynamics.

Asexual Reproduction of Aurelia coerulea Polyps in situ on Settling Plates in Jiaozhou Bay,China

Jellyfish blooms are increasingly prevalent coastal phenomena,with Aurelia coerulea being a significant contributor.The complex life history of jellyfish,featuring a sessile polyp stage,is a key factor in bloom formation,yet it is challenging to study in the field.This study aimed to describe the asexual reproduction of A.coerulea polyps in Jiaozhou Bay,China,and to assess their ability to form sedentary colonies and their relationship with environmental factors.Using settling plates,we observed polyps in situ and documented three asexual reproduction modes:budding,strobilation,and podocyst formation.Environmental parameters including temperature,salinity,dissolved oxygen(DO),chlorophyll a(Chl a),and the biomass of phytoplankton and zooplankton were monitored.Budding was the predominant reproductive method,featuring stolon budding in autumn and direct budding during the winter and spring seasons.Strobilation took place in the colder months,releasing ephyrae between April and May.Polyp abundance was positively correlated with seawater temperature and negatively correlated with DO concentration.Polyps at 1.0 m depth showed higher survivorship and proliferation over 8 months,whereas those at 2.0 m depth experienced a steady decline and died within 4 months.The study enhances our understanding of the life cycle and asexual reproduction strategies of A.coerulea polyps in the field,with implications for predicting and managing jellyfish blooms.The findings underscore the importance of temperature and DO in polyp survival and suggest that initial polyp population proliferation is crucial for long-term survival.

The life-history trait trade-offs mediated by reproduction and immunity in the brown planthopper,Nilaparvata lugens Stål

Reproduction and immune defense are costly functions,and they are expected to tradeoff with each other to drive evolution.The brown planthopper(BPH),Nilaparvata lugens Stål(Hemiptera,Delphacidae),is a global superpest that mostly damages rice crops.Yeast-like symbionts(YLS)exist in the abdominal fat body tissue and are tightly associated with the development,growth,and reproduction of BPH.Our previous research demonstrated that mating behavior promotes the release of YLS from the fat body into the hemolymph in the BPH,thereby triggering an immune response.Additionally,the fitness costs related to life-history traits of BPH(such as survival rate)have a strong dependence on the relative abundance of YLS.However,the possible relationship between reproduction and the immune response in BPH has not been identified.In this study,an omics-based approach was used to analyze the transcriptome of fat body tissues in mated and unmated BPH at 72 h post-eclosion,from which two antimicrobial peptide genes,NlDefensin A(NlDfA)and NlDefensin B(NlDfB),were selected since they were highly expressed in mated BPH.Subsequently,the full-length cDNA sequences of the NlDfA and NlDfB genes were cloned and analyzed.qPCR results showed up-regulation of the NlDfA and NlDfB genes in mated BPH when compared to unmated BPH.Spatial-temporal expression analysis indicated that the NlDfA and NlDfB genes were expressed in all tissues and developmental stages,and they were most highly expressed in the fat body at 24 h post-eclosion.Moreover,the symbionts in BPH were significantly inhibited by the in vitro expression of the NlDfA and NlDfB proteins.Furthermore,RNA interference(RNAi)-mediated suppression of NlDfA and NlDfB dramatically increased the relative abundance of YLS in the fat body,while YLS in the hemolymph decreased significantly.These BPHs also displayed some fitness disadvantages in survival,fecundity,hatchability,and possibly the vertical transmission of YLS from hemolymph to egg.Our results indicated that mating could heighten the immunity of BPH by upregulating the expression of the NlDfA and NlDfB genes,which protect the host from pathogen challenges during reproduction.However,the reduced content of YLS may act as a fitness disadvantage in dictating the life-history traits of BPH.This work has significant theoretical and practical implications for the precise green control technology that involves crucial gene targeting,as well as for the“endosymbionts for pest control”strategy in insects.

Tissue distribution of cadmium and its effect on reproduction in Spodoptera exigua

Vegetable fields are often contaminated by heavy metals,and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding.In this study,cadmium accumulation in the tissues of S.exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated.Under the stress of different concentrations of cadmium(0.2,3.2,and 51.2 mg kg^(-1)),the cadmium content in each tissue of S.exigua increased in a dose-dependent manner.At the larval stage,the highest cadmium accumulation was found in midgut in all three cadmium treatments,but at the adult stage,the highest cadmium content was found in fat body.In addition,the cadmium content in ovaries was much higher than in testes.When F1S.exigua was stressed by cadmium and the F_(2)generation was not fed a cadmium-containing diet,the larval survival,pupation rate,emergence rate and fecundity of the F_(2)generation were significantly reduced in the 51.2 mg kg^(-1)treatment compared to the corresponding F1generation.Even in the F_(2)generation of the 3.2 mg kg^(-1)treatment,the fecundity was significantly lower than in the parental generation.The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg^(-1)cadmium exposure levels.When only mothers were stressed at the larval stage,the fecundity of the F_(2)generation was significantly lower than that of the F1generation in the 51.2 mg kg^(-1)treatment,and it was also significantly lower than in the 3.2 and 0.2 mg kg^(-1)treatments.The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution.

ISSUES AND MEASURES ON ASSISTED REPRODUCTION BY ACUPUNCTURE ABROAD

As the application of acupuncture has been increased year by year in the field of overseas reproduction, it has become crucial to give a scientific and objective evaluation of the safety and efficacy of acupuncture in the field of assisted reproduction, which attaches great importance to the sustainable development of acupuncture in the field of reproduction. This article aims to introduce the current situation of overseas clinical study in the field of assisted reproduction, analyze the existing issues profoundly and put forward measures to solve them, in order to enhance the level of international clinical study of acupuncture.

Research on Development Mode of Solid Ancient Towns Based on Cultural Reproduction——A Case Study of Zouma Ancient Town in China

The paper had pointed out hollow ancient town was the result of urbanization and desire; and analyzed that hollowness made ancient towns degenerate in nature, economy and social function, seriously blocking the sustainable development of economic society of ancient towns. Based on the connotation and idea of cultural reproduction, in terms of application of basic theories of cultural ecology and restoration ecology, it had established tourism development of solid ancient towns, which had been analyzed specifically from the perspectives of representation of ancient towns'scene, cultural realization and cultural promotion. By taking Zouwa Ancient Town in the west of the main urban area of Chongqing City for example, it had discussed tourism development practice of ancient towns, emphasized making Zouma scene reappear from the aspects of pattern protection, restoration and treatment of ecological environment, ancient towns' protection and cultural facilities' construction, experiencing and publicizing Zouma culture. It also highlighted taking historical and cultural heritages as the theme of tourist products, and proposed development mode of solid ancient towns, realizing reproduction of cultural heritage.

Advances in Small RNAs and Sexual Reproduction in Plants

Small RNAs are non-coding RNA molecules with 20-30 nucleotides （nt） in length that mainly play regulatory roles in gene expression at the post-transcription level by directly cutting target mRNA or inhibiting its translation. Small RNAs play regulatory roles in the growth and development process of plants at the core of gene regulatory networks, which has been widely studied and confirmed in sporophyte generation of plants. However, few researches have been conducted on small RNAs and gametophyte generation. It is reported that small RNAs play important roles in floral organ development, gametogenesis, fertilization, and early zygotic development of plants. In addition, various small RNAs also play roles in controlling genetic integrity, cell differentiation and functions during the sexual reproduction process of plants. However, most of the specific functions of small RNAs in the sexual reproduction process are unknown yet. This study mainly aimed to introduce small RNAs in plants, summarize the latest advances in researches of small RNAs and plant sexual reproduction, and make prospect on its future.

Study on Flowering, Cultivation, and Reproduction of Agave americana Var. Marginata Hort. (Agavaceae)

Agave americana Var. Marginata Hort. （Agavaceae） is a perennial herb. This paper summarized its classification, distribution, morphological characteristics, habit, flowering and fruiting, cultivation and reproduction, as well as multiple uses in daily life, which provided references for the exploitation and utilization of Agave americana Vat. Marginata Hort. （Agavaceae）.

The role of dietary fibre in pig production,with a particular emphasis on reproduction

Fibres from a variety of sources are a common constituent of pig feeds. They provide a means to utilise locallyproduced plant materials which are often a by-product of the food or drink industry. The value of a high fibre diet in terms of producing satiety has long been recognised. However the addition of fibre can reduce feed intake, which is clearly detrimental during stages of the production cycle when nutrient needs are high, for example in growing piglets and during lactation. More recently, fibre has been found to promote novel benefits to pig production systems,particularly given the reduction in antimicrobial use world-wide, concern for the welfare of animals fed a restricted diet and the need to ensure that such systems are more environmentally friendly. For example, inclusion of dietary fibre can alter the gut microbiota in ways that could reduce the need for antibiotics, while controlled addition of certain fibre types may reduce nitrogen losses into the environment and so reduce the environmental cost of pig production.Of particular potential value is the opportunity to use crude fibre concentrates as ’functional’ feed additives to improve young pig growth and welfare. Perhaps the greatest opportunity for the use of high fibre diets is to improve the reproductive efficiency of pigs. Increased dietary fibre before mating improves oocyte maturation, prenatal survival and litter size; providing a consumer-acceptable means of increasing the amount of saleable meat produced per sow. The mechanisms responsible for these beneficial effects remain to be elucidated. However, changes in plasma and follicular fluid concentrations of key hormones and metabolites, as well as effects of the hypothalamic satiety centre on gonadotrophin secretion and epigenetic effects are strong candidates.

Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River

Silver carp(Hypophthalmichthys molitrix),bighead carp(Aristichthys nobilis),grass carp(Ctenopharyngodon idella),and black carp(Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China.Reproduction of these carp has declined since the construction of the Three Gorges Dam(TGD) due to an altered water flow and thermal regime in the Changjiang(Yangtze) River.However,details of the changes in reproduction of the four species are not well understood.To assess the impact of the TGD on reproduction of the four carp,we investigated their eggs and larvae at Yidu City,which is 80 km below the TGD,during 2005-2012.We examined differences in larval abundance of the four species in the Jianli section(350 km downstream of the TGD) before(1997-2002)and after(2003-2012) construction of the TGD.Based on these observations,the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed.Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million,which were significant decreases since the 1980 s.Moreover,larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction(ANCOVA,P<0.05).The observed larval abundance accounted for only 24.66%of the predicted value in 2003 when the dam was first inundated.The present spawning grounds between the TGD and Yidu section of the river are very similar to those described in the 1980 s,and some spawning grounds exist upstream of the TGD.Large free-flowing stretches upstream of the TGD and the creation of artificially flooded downstream reaches are needed to stimulate spawning and effectively conserve these four major Chinese carps species.

Effect of temperature and irradiance on the growth and reproduction of Enteromorpha prolifera J.Ag.(Chlorophycophyta,Chlorophyceae)

Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.

Impact of brine acidification on hatchability, survival and reproduction of Artemia parthenogenetica and Artemia franciscana in salt ponds, Bohai Bay, China

We studied the effect of pH （pH 5, 6, 7 and 8） on the hatching percentage, survival and reproduction of Artemia strains in Bohai Bay salt ponds. Strains included parthenogenetic Artemia from Bohai Bay （BHB）, Artemiafranciscana from San Francisco Bay, and A. franciscana artificially produced in salt ponds in Vietnam. The latter was included as a potential inoculum for biological management of salt ponds. The hatching percentage of cysts after 24 h and the survival rate of the tested Artemia strains were significantly reduced when exposed to a culture medium at pH 5 for 18 d （P〈0.05）. The tolerance of Artemia to 48 h acid exposure varied with developmental stage, increasing in the following order： juvenile, nauplii, pre-adult, with maximum tolerance in adults. All strains of Artemia tested could not reproduce at pH 5. At pH levels from pH 6-8, a higher pH generally resulted in a shorter brood interval and enhanced ovoviviparity. Hence, we suggest that brine acidification has a negative impact on Artemia populations in the Bohai Bay saltworks. Inoculation of Artemia with either local parthenogenetic Artemia or exotic A. franeiscana should be feasible at pH 7-8.

The type, position and age effect on the cutting reproduction of Picea crassifolia and its rooting mechanism in the Qilian Mountains

Picea crassifolia Kom, a perennial arbor spe- cies is recognized as one of the most adaptable plants found to date in Qilian Mountains. To explore the cutting reproduction technology of P. crassifolia and reveal its rooting mechanism, cuttings of P. crassifolia with different cutting types （softwood, hardwood and root）, positions （top, upper, middle and bottom） and ages （7, 10, 15, 20, 25 year-old） were cultivated in a field experiment. One- year old softwood and hardwood cuttings were collected from 7-, 10-, 15-, 20-, and 25 year-old healthy ortets to analyze the changes from endogenous hormones and organic nutrients. Results indicate that the softwood cut- tings （0.5-1.0 cm in diameter） from upper branches of 15 year-old ortets shows better growth performance by improving rooting indexes, including a significant increasein rooting rate and a decrease in basal rot rate. Concomi- tantly, increasing rooting quantity and root length also increased. It is noteworthy that the high rooting rate of P. crassifolia cuttings due to its ability to accumulate high concentrations of indole-3-acetic acid （IAA） and total carbon （TC） rather than abscisic acid （ABA） and total nitrogen （TN）. The rooting rate was mainly regulated by the IAA/ABA and TC/TN ratio. In summary, our results suggest that the softwood cuttings （0.5-1.0 cm in diameter） from upper branches of 15 year-old P. crassifolia can be considered as an effective strategy to improve cutting rooting rate, and the IAA/ABA and TC/TN ratio was one of the main factors limiting the cutting rooting rate of P. crassifolia.

Adult nutrition affects reproduction and flight performance of the invasive fall armyworm,Spodoptera frugiperda in China

Floral resources,such as carbohydrate-rich nectar or pollen,can bolster fitness and raise reproductive output of adult lepidopterans.Here,we used laboratory experiments to assess how those plant-derived foods impact adult fecundity,reproductive physiology and flight performance of an invasive strain of the fall armyworm,Spodoptera frugiperda(FAW;Lepidoptera:Noctuidae)in China.More specifically,supplementary feeding on bee pollen and honey enhanced FAW flight duration,testis size,ovarian development,longevity and adult fecundity.FAW adults attained the longest pre-oviposition(10.8 days)and oviposition period(6.8 days)and longevity(19.2 days)on 5%acacia honey.Upon access to 2.5%acacia honey and 2.5‰pine pollen,S.frugiperda attained the highest mating rate(79.7%),fecundity(644.9 eggs/female)and egg hatching rate(82.3%).Feeding on honey further delayed decay of male testes,while ovarian development was enhanced when female moths were allowed access to 2.5%honey and 2.5‰pine pollen.Upon feeding on 5%honey solution,S.frugiperda engaged in flight over the longest duration(9.5 h),distance(29.9 km)and speed(3.1 km h-1).Honey had a comparatively greater effect on the above parameters than pollen.Our findings help decipher FAW invasion patterns and population dynamics,facilitate the development of nutritional attractants,and contribute to integrated pest management of this newly-invasive pest in eastern Asia.

Joint action of phoxim and fenvalerate on reproduction in male rats

Aim: To evaluate the joint action of phoxim and fenvalerate on the reproductive function in male Sprague-Dawley rats. Methods: The 2×2 factorial analysis experiment was used in the study. The pesticides were orally given at daily doses of phoxim (Pho) 8.2 nig/kg, fenvalerate (Fen) 3.3 mg/kg and Pho 8.2+Fen 3,3 mg/kg (Pho:Fen = 5:2), 5 days a week for 60 days. Sperm motility was measured with computer-assisted sperm motility analysis (CASA) and daily sperm production estimated. Immunoenzymatic method and electron microscopy were used to evaluate the serum testosterone and the testicular morphology, respectively. Results: There were significant decreases in sperm motility parameters in the treated animals, including straight line velocity (VSL), beat cross frequency (BCF), linearity (LIN) and straightness (STR). After treated with Fen, significant decreases in VSL, LIN and STR were demonstrated. Significant decreases of daily sperm production were seen in animals treated with Pho and Pho+Fen in comparison with the controls. Serum testosterone levels were not significantly changed in the treated groups. Factorial ANOVA showed that no significant interactions were noted between Pho and Fen in sperm motility, sperm production and serum testosterone. Both the single and mixed pesticides caused various degrees of testicular lesions, involving vacuolation of endoplasmic reticulum and necrosis of Sertoli cells. Conclusion: The pesticides may cause sperm motility changes and testicular lesions in male rats. The action of Pho and Fen may be additive.

How cushion communities are maintained in alpine ecosystems： A review and case study on alpine cushion plant reproduction

Cushion species occur in nearly all alpine environments worldwide. In past decades, the adaptive and ecosystem-engineering roles of such highly specialized life forms have been well studied. However, the adaptive strategies responsible for cushion species reproductive success and maintenance in severe alpine habitats remain largely unclear. In this study, we reviewed the current understanding of reproductive strategies and population persistence in alpine cushion species. We then present a preliminary case study on the sexual reproduction of Arenaria polytrichoides(Caryophyllaceae), a typical cushion species inhabiting high elevations of the Himalaya Hengduan Mountains, which is a hotspot for diversification of cushion species. Finally, we highlight the limitations of our current understanding of alpine cushion species reproduction and propose future directions for study.

The impact of male overweight on semen quality and outcome of assisted reproduction

It is well-documented that male overweight and obesity causes endocrine disorders that might diminish the male reproductive capacity; however, reports have been conflicting regarding the influence of male body mass index （BMI） on semen quality and the outcome of assisted reproductive technology （ART）. The aim of this study was to investigate whether increased male BMI affects sperm quality and the outcome of assisted reproduction in couples with an overweight or obese man and a non-obese partner. Data was prospectively collected from 612 infertile couples undergoing ART at a Danish fertility center. Self-reported information on paternal height and weight were recorded and BMI was calculated. The men were divided into four BMI categories： underweight BMI 〈 20 kgm^-2, normal BMI 20-24.9 kg m^-2, overweight BMI 25-29.9 kgm^-2 and obese BMI 〉 30 kgm^-2. Conventional semen analysis was performed according to the World Health Organization guideline and sperm DNA integrity was analyzed by the Sperm Chromatin Structure Assay （SCSA）. No statistically significant effect of male BMI was seen on conventional semen parameters （sperm concentration, total sperm count, seminal volume and motility） or on SCSA-results. Furthermore, the outcome of ART regarding fertilization rate, number of good quality embryos （GQE）, implantation and pregnancy outcome was not influenced by the increasing male BMIo

Growth and Reproduction of Artificially Fed Cnaphalocrocis medinalis

The growth and reproduction of rice leaffolder,Cnaphalocrocis medinalis,fed on an artificial diet were studied.The results showed that the larvae were able to grow and pupate on the artificial diet.The durations of larvae and pupas of C.medinalis on the artificial diet were 28.1 d and 10.1 d,postponed 4.9 d and 1.7 d respectively,compared with those reared with rice leaves.The number of ovipositions was 41.6 per female,26.2% higher than that fed on rice leaves.Survival rate curve of larvae was a descent function of mortality-age,with no significant differences from the curve of larvae fed on rice leaves.The net reproductive rate （Ro）,intrinsic rate of increase （rm） and finite rate of increase （λ） of the population fed on diet were 17.6928,0.0884 and 1.0924,respectively,and the mean generation time （T） and double time （td） were prolonged 4.9 d and 1.3 d in comparison with the treatment of rice leaves.Population trend index （I） was 3.26,indicating a growing number of the population of C.medinalis fed on artificial diet.

The effects of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus(Copepoda:Calanoida)

DDT （dichloro-diphenyl-trichloroethane） as a type of organochlorine pesticides, is an important compo nent of pesticides pollution whose impact on the marine ecosystem is urgently to be evaluated. To investi gate the biological effects of DDT on the marine ecosystem, copepods being the main contributor of sec ondary productivity in the marine ecosystem, were selected as target animals. The influence of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus （S. tenellus） was analyzed and the antioxidant enzymes activities in the individuals were measured under different exposure concentrations of DDT. The 48 h median lethal concentration （LC50） and 96 h LC50 of DDT to S. tenellus were 5.44 and 2.50 pg/dma, respectively. The filtration rates, grazing rates, and respiration of S. tenellus decreased apparently with increased DDT concentrations. Under lower concentration （〈625 ng/dm3） of DDT, the activities of the antioxidant enzymes, including superoxide dismutase and catalase in the animals increased significantly compared with those in the animals without any exposure to DDT, which suggested that the antioxidant enzymes can protect the animals from oxidative damage. However, the activity of the antioxidant enzyme decreased when the animals were exposed to higher concentration （1250-2 500 ng/dma） of DDT. The sur-vival rate of both females and males was reduced when they were exposed to DDT less than 250 ng/dm3, but females showed higher survival rate than males when they are under the same concentration. The hatching ratio and the egg diameters of S. tenellus decreased significantly when they were exposed to DDT with a concentration of 25 and 250 ng/dm3, however, the cumulative egg production did not show any significant variation when the animals were exposed to the above DDT concentration. These data in the preset study suggested that exposure to DDT can cause the variation of the species composition of copepods, and further affect the marine ecosystem.

Can Helicobacter pylori infection influence human reproduction?

Helicobacter pylori (H. pylori) infection could be associated with extra-digestive diseases. Here, we report the evidences concerning the decrease in reproductive potential occurring in individuals infected by H. pylori, especially by strains expressing CagA. This infection is more prevalent in individuals with fertility disorders. Infected women have anti-H. pylori antibodies in cervical mucus and follicular fluid that may decrease sperm motility and cross react immunologically with spermatozoa, conceivably hampering the oocyte/sperm fusion. Infection by CagA positive organisms enhances the risk of preeclampsia, which is a main cause of foetus death. These findings are supported by the results of experimental infections of pregnant mice, which may cause reabsorption of a high number of foetuses and alter the balance between Th1 and Th2 cell response. Infected men have decreased sperm motility, viability and numbers of normally shaped sperm and augmented systemic levels of inflammatory cytokines, such as tumor necrosis factor-&#x003b1;, which may damage spermatozoa. In countries where parasitic infestation is endemic, detrimental effects of infection upon spermatozoa may not occur, because the immune response to parasites could determine a switch from a predominant Th1 type to Th2 type lymphocytes, with production of anti-inflammatory cytokines. In conclusion, the evidences gathered until now should be taken into consideration for future studies aiming to explore the possible role of H. pylori infection on human reproduction.